Professional Education

  • Doctor of Medicine, Osaka University (2006)
  • Bachelor of Pharmacy, Kyoto University (1999)

Stanford Advisors

All Publications

  • Time based versus strain based myocardial performance indices in hypertrophic cardiomyopathy, the merging role of left atrial strain. European heart journal cardiovascular Imaging Kobayashi, Y., Moneghetti, K. J., Bouajila, S., Stolfo, D., Finocchiaro, G., Kuznetsova, T., Liang, D., Schnittger, I., Ashley, E., Wheeler, M., Haddad, F. 2018


    Aims: The myocardial performance index (MPI) is a time-based index of global myocardial performance. In this study, we sought to compare the prognostic value of the MPI with other strain and remodelling indices in hypertrophic cardiomyopathy (HCM).Methods and results: We enrolled 126 patients with HCM and 50 age- and sex-matched controls. Along with traditional echocardiographic assessment, MPI, left ventricular global longitudinal strain (LVGLS), E/e' ratio, and total left atrial (LA) global strain (LAS) were also measured. Time-based MPI was calculated from flow or tissue-based pulse wave Doppler (PWD and TDI) as the (isovolumic-relaxation and contraction time)/systolic-time. We used hierarchical clustering and network analysis to better visualize the relationship between parameters. The primary endpoint was the composite of all-cause death, heart transplantation, left ventricular assist device implantation, and clinical worsening. Left ventricular outflow tract (LVOT) obstruction was present in 56% of patients. Compared with controls, patients with HCM had worse LVGLS (-14.0±3.4% vs. -19.6±1.5%), higher E/e' (12.9±7.2 vs. 6.1±1.5), LA volume index (LAVI) (36.4±13.8ml/m2 vs. 25.6±6.7ml/m2), and MPI (0.55±0.17 vs. 0.40±0.11 for PWD and 0.59±0.22 vs. 0.46±0.09 for TDI) (all P<0.001). During a median follow-up of 55months, 47 endpoints occurred. PWD or TDI-based MPI was not associated with outcome, while LAVI, LAS, LVGLS, and E/e' were (all P<0.01). On multivariable analysis, LVOT obstruction (P<0.001), LAS (P<0.001), and E/e' (P=0.02) were retained as independent associates. They were in different clusters suggesting complemental relationship between them.Conclusion: Time-based index is less predictive of outcome than strain or tissue Doppler indices. LAS may be a promising prognostic marker in HCM.

    View details for DOI 10.1093/ehjci/jey097

    View details for PubMedID 30060097

  • Long-term prognostic value of invasive and non-invasive measures early after heart transplantation. International journal of cardiology Kobayashi, Y., Kobayashi, Y., Yang, H. M., Bouajila, S., Luikart, H., Nishi, T., Choi, D. H., Schnittger, I., Valantine, H. A., Khush, K. K., Yeung, A. C., Haddad, F., Fearon, W. F. 2018; 260: 31–35


    Invasively assessed coronary microvascular resistance early after heart transplantation predicts worse long-term outcome; however, little is known about the relationship between microvascular resistance, left ventricular function and outcomes in this setting.A total of 100 cardiac transplant recipients had fractional flow reserve (FFR) and the index of microcirculatory resistance (IMR) measured in the left anterior descending artery and echocardiographic assessment of left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) at 1 year after heart transplantation. The primary endpoint was the composite of death and retransplantation occurring beyond the first post-operative year.The mean FFR, IMR, LVEF, and GLS values at 1 year were 0.87 ± 0.06, 21.3 ± 17.3, 60.4 ± 5.4%, and 14.2 ± 2.4%, respectively. FFR and IMR had no significant correlation with LVEF and GLS. During a mean follow-up of 6.7 ± 4.2 years, the primary endpoint occurred in 24 patients (24.0%). By ROC curve analysis, IMR = 19.3 and GLS = 13.3% were the best cutoff values for predicting death or retransplantation. Cumulative event-free survival was significantly lower in patients with higher IMR (log-rank p = 0.02) and lower GLS (log-rank p < 0.001). Cumulative event-free survival can be further stratified by the combination of IMR and GLS (long-rank p < 0.001). By multivariable Cox proportional hazards model, higher IMR and lower GLS were independently associated with long-term death or retransplantation (elevated IMR, hazard ratio = 2.50, p = 0.04 and reduced GLS, hazard ratio = 3.79, p = 0.003, respectively).Invasively assessed IMR does not correlate with GLS at 1 year after heart transplantation. IMR and GLS determined at 1 year may be used as independent predictors of late death or retransplantation.

    View details for DOI 10.1016/j.ijcard.2018.01.070

    View details for PubMedID 29622448

  • Dynamic changes in aortic impedance after transcatheter aortic valve replacement and its impact on exploratory outcome. international journal of cardiovascular imaging Kobayashi, Y., Kim, J. B., Moneghetti, K. J., Kobayashi, Y., Zhang, R., Brenner, D. A., O'Malley, R., Schnittger, I., Fischbein, M., Miller, D. C., Yeung, A. C., Liang, D., Haddad, F., Fearon, W. F. 2017


    Valvulo-arterial impedance (Zva) has been shown to predict worse outcome in medically managed aortic stenosis (AS) patients. We aimed to investigate the association between Zva and left ventricular (LV) adaptation and to explore the predictive value of Zva for cardiac functional recovery and outcome after transcatheter aortic valve replacement (TAVR). We prospectively enrolled 128 patients with AS who underwent TAVR. Zva was calculated as: (systolic blood pressure + mean transaortic gradient)/stroke volume index). Echocardiographic assessment occurred at baseline, 1-month and 1-year after TAVR. The primary endpoints were to investigate associations between Zva and global longitudinal strain (GLS) at baseline as well as GLS change after TAVR. The secondary was to compare all-cause mortality after TAVR between patients with pre-defined Zva (=5 mmHg m(2)/ml), stroke volume index (=35 ml/m(2)), and GLS (=-15%) cutoffs. The mean GLS was reduced (-13.0 ± 3.2%). The mean Zva was 5.2 ± 1.6 mmHg*m(2)/ml with 55% of values ≥5.0 mmHg*m(2)/ml, considered to be abnormally high. Higher Zva correlated with worse GLS (r = -0.33, p < 0.001). After TAVR, Zva decreased significantly (5.1 ± 1.6 vs. 4.5 ± 1.6 mmHg*m(2)/ml, p = 0.001). A reduction of Zva at 1-month was associated with GLS improvement at 1-month (r = -0.31, p = 0.001) and at 1-year (r = -0.36 and p = 0.001). By Kaplan-Meier analysis, patients with higher Zva at baseline had higher mortality (Log-rank p = 0.046), while stroke volume index and GLS did not differentiate outcome (Log-rank p = 0.09 and 0.25, respectively). As a conclusion, Zva is correlated with GLS in AS as well as GLS improvement after TAVR. Furthermore, a high baseline Zva may have an additional impact to traditional parameters on predicting worse mortality after TAVR.

    View details for DOI 10.1007/s10554-017-1155-6

    View details for PubMedID 28516313

  • Left ventricular myocardial function assessed by three-dimensional speckle tracking echocardiography in Takotsubo cardiomyopathy. Echocardiography (Mount Kisco, N.Y.) Kobayashi, Y., Okura, H., Kobayashi, Y., Fukuda, S., Hirohata, A., Yoshida, K. 2017


    We aimed to investigate left ventricular (LV) functional recovery in Takotsubo cardiomyopathy (TC) using three-dimensional (3D) speckle tracking echocardiography.Twenty-one patients with TC who underwent routine and 3D echocardiography as well as electrocardiography were enrolled. 3D images were analyzed to measure 3D radial strain and area tracking (area change of each LV segment). Postsystolic shortening (PSS) or thickening (PST) was defined as a further shortening or thickening occurred after the end-systole. 3D echocardiography and ECG were repeated at 4 weeks and 6 months later.Mean age was 70.9±11.1 years, and 18 (86%) patients were female. All patients presented classical type of TC with apical ballooning. LV ejection fraction (EF) improved from 49.9±7.2 to 64.9±6.0% (P<.001) at 4 weeks without segmental wall-motion abnormality. However, PSS or PST still existed in 43% of LV segments, and electrocardiographic abnormality was also observed in 51% at 4 weeks and disappeared at 6 months. Mean 3D radial strain decreased from baseline to 6 months at base (36.1±19.6 vs 28.0±12.6%, P=.04), whereas it increased at mid (16.2±7.2 vs 28.7±9.1%, P=.03) and the apex (8.0±4.4 vs 21.2±7.9%, P<.001). Mean area tracking increased from baseline to 6 months at mid and apex (-28.5±9.5 vs -44.5±9.6%, P<.001 for mid, and -24.2±13.0 vs -42.9±16.8%, P=.002 for the apex), while it did not change at base (-37.0±8.9 vs -41.9±9.6%, P=NS).Patients with TC show abnormal wall motion during acute phase. Even after LV wall-motion recovery, subtle abnormalities of regional LV function appear to persist at 4 weeks followed by normalization at 6 months.

    View details for DOI 10.1111/echo.13492

    View details for PubMedID 28266731

  • Incremental Value of Deformation Imaging and Hemodynamics Following Heart Transplantation: Insights From Graft Function Profiling. JACC. Heart failure Kobayashi, Y., Sudini, N. L., Rhee, J. W., Aymami, M., Moneghetti, K. J., Bouajila, S., Kobayashi, Y., Kim, J. B., Schnittger, I., Teuteberg, J. J., Khush, K. K., Fearon, W. F., Haddad, F. 2017; 5 (12): 930–39


    This study investigated to define graft dysfunction and to determine its incremental association with long-term outcome after heart transplantation (HT).Although graft failure is an established cause of late mortality after HT, few studies have analyzed the prognostic value of graft dysfunction at 1- and 5-year follow-up of HT.Patients who underwent HT and completed their first annual evaluation with right heart catheterization and echocardiography at Stanford University between January 1999 and December 2011 were included in the study. Hierarchical clustering was used to identify modules to capture independent features of graft dysfunction at 1 year. The primary endpoint for analysis consisted of the composite of cardiovascular mortality, re-transplantation, or heart failure hospitalization within 5 years of HT. The study further explored whether changes in graft dysfunction between 1 and 5 years were associated with 10-year all-cause mortality.A total of 215 HT recipients were included in the study. Using hierarchical clustering, 3 functional modules were identified; among them, left ventricular global longitudinal strain (LVGLS), stroke volume index, and right atrial pressure (RAP) or pulmonary capillary wedge pressure (PCWP) captured key features of graft function. Graft dysfunction based on pre defined LVGLS in absolute value <14%, stroke volume index <35 ml/m2, RAP >10 mm Hg, or PCWP >15 mm Hg were present in 41%, 36%, and 27%, respectively. The primary endpoint at 5 years occurred in 52 patients (24%), whereas 10-year all-cause mortality occurred in 30 (27%) of 110 patients alive at 5 years. On multivariate analysis, RAP (standardized hazard ratio: 1.63), LVGLS (standardized hazard ratio: 1.39), and a history of hemodynamically compromising rejection within 1 year (hazard ratio: 2.18) were independent predictors of 5-year outcome. RAP at 5 years, as well as change in RAP from 1 to 5 years, was predictive of 10-year all-cause mortality.RAP and LVGLS at the first annual evaluation provide complementary prognostic information in predicting 5-year outcome after HT.

    View details for DOI 10.1016/j.jchf.2017.10.011

    View details for PubMedID 29191301

  • Challenging the complementarity of different metrics of left atrial function: insight from a cardiomyopathy-based study. European heart journal cardiovascular Imaging Kobayashi, Y., Moneghetti, K. J., Boralkar, K., Amsallem, M., Tuzovic, M., Liang, D., Yang, P. C., Narayan, S., Kuznetsova, T., Wu, J. C., Schnittger, I., Haddad, F. 2016


    Left ventricular (LV) strain provides incremental values to LV ejection fraction (LVEF) in predicting outcome. We sought to investigate if similar relationship is observed between left atrial (LA) emptying fraction and LA strain.In this study, we selected 50 healthy subjects, 50 patients with dilated, 50 hypertrophic, and 50 infiltrative (light-chain (AL) amyloidosis) cardiomyopathy (CMP). Echocardiographic measures included LVEF and LA emptying fraction as well as LV and LA longitudinal strain (LVLS and LALS). After regression analysis, comparison of least square means of LA strain among aetiologies was performed. Intraclass correlation coefficient (ICC) and coefficient of variation (COV) were used in the assessment of variability and reproducibility of LV and LA metrics. The mean LVLS and all LA metrics were impaired in patients with all CMP compared with healthy subjects. In contrast to the moderate relationship between LVEF and LVLS (r = -0.51, P < 0.001), there was a strong linear relationship between LA emptying fraction and LA strain (r = 0.87, P < 0.001). In multiple regression analysis, total LA strain was associated with LVLS (β = -0.48, P < 0.001), lateral E/e' (β = -0.24, P < 0.001), age (β = -0.21, P < 0.001), and heart rate (β = -0.14, P = 0.02). The least square mean of LA strain adjusted for the parameters was not different among aetiologies (ANOVA P = 0.82). The ICC (>0.77) and COV (<13) were acceptable.In contrast to LV measures, there is a strong linear relationship between volumetric and longitudinal deformation indices of left atrium irrespective of CMP aetiology. Either LA emptying fraction or LA strain could be used as an important parameter in predictive models.

    View details for PubMedID 27638850

  • Assessment of Atrial Synchrony in Paroxysmal Atrial Fibrillation and Impact of Pulmonary Vein Isolation for Atrial Dyssynchrony and Global Strain by Three-Dimensional Strain Echocardiography JOURNAL OF THE AMERICAN SOCIETY OF ECHOCARDIOGRAPHY Kobayashi, Y., Okura, H., Kobayashi, Y., Okawa, K., Banba, K., Hirohata, A., Tamada, T., Obase, K., Hayashida, A., Yoshida, K. 2014; 27 (11): 1193-1199
  • Cytokines profile of reverse cardiac remodeling following transcatheter aortic valve replacement. International journal of cardiology Kim, J. B., Kobayashi, Y., Kuznetsova, T., Moneghetti, K. J., Brenner, D. A., O'Malley, R., Dao, C., Wu, J. C., Fischbein, M., Craig Miller, D., Yeung, A. C., Liang, D., Haddad, F., Fearon, W. F. 2018; 270: 83–88


    OBJECTIVE: Previous studies have suggested that cytokines and growth factors may predict ventricular recovery following aortic valve replacement (AVR). The primary objective of this study was to identify cytokines that predict ventricular recovery following transcatheter AVR (TAVR).METHODS: We prospectively enrolled 121 consecutive patients who underwent TAVR. Standard echocardiographic assessment at baseline, 1-month and 1-year after TAVR included left ventricular (LV) mass index (LVMI) and global longitudinal strain (GLS). Blood samples were obtained at the time of the procedure to measure cytokines using a 63-plex Luminex platform. Partial least squares-discriminant analysis was performed to identify cytokines associated with ventricular remodeling and function at baseline as well as 1 year after TAVR.RESULTS: The mean age was 84 ± 9 years, with a majority of male subjects (59%), a mean LVMI of 120.4 ± 45.1 g/m2 and LVGLS of -13.0 ± 3.2%. On average, LV mass decreased by 8.1% and GLS improved by 20.3% at 1 year following TAVR. Among cytokines assayed, elevated hepatocyte growth factor (HGF) emerged as a common factor significantly associated with worse baseline LVMI and GLS as well as reduced ventricular recovery (p < 0.005). Other factors associated with ventricular recovery included a select group of vascular growth factors, inflammatory mediators and tumor necrosis factors, including VEGF-D, ICAM-1, TNFbeta, and IL1beta.CONCLUSION: We identified a network of cytokines, including HGF, that are significantly correlated with baseline LVMI and GLS, and ventricular recovery following TAVR.

    View details for DOI 10.1016/j.ijcard.2018.05.020

    View details for PubMedID 30219541

  • Forgotten No More: A Focused Update on the Right Ventricle in CardiovascularDisease. JACC. Heart failure Amsallem, M., Mercier, O., Kobayashi, Y., Moneghetti, K., Haddad, F. 2018


    In the last decade, there has been renewed interest in the study of the right ventricle. It is now well established that right ventricular function is a strong predictor of mortality, not only in heart failure but also in pulmonary hypertension, congenital heart disease, and cardiothoracic surgery. The right ventricle is part of a cardiopulmonary unit with connections to the pulmonary circulation, venous return, atria, and left ventricle. In this context, ventriculoarterial coupling, interventricular interactions, and pericardial constraint become important to understand right ventricular adaptation to injury or abnormal loading conditions. This state-of-the-art review summarizes major advances that occurred in the field of right ventricular research over the last decade. The first section focuses on right ventricular physiology and pulmonary circulation. The second section discusses the emerging data on right ventricular phenotyping, highlighting the importance of myocardial deformation (strain) imaging and assessment of end-systolic dimensions. The third section reviews recent clinical trials involving patients at risk for or with established right ventricular failure, focusing on beta blockade, phosphodiesterase inhibition, and mechanical support of the failing right heart. The final section presents a perspective on active areas of research that are most likely to translate in clinical practice in the next decade.

    View details for DOI 10.1016/j.jchf.2018.05.022

    View details for PubMedID 30316939

  • Optimizing right ventricular focused four-chamber views using three-dimensional imaging, a comparative magnetic resonance based study. The international journal of cardiovascular imaging Amsallem, M., Lu, H., Tang, X., Do Couto Francisco, N. L., Kobayashi, Y., Moneghetti, K., Shiran, H., Rogers, I., Schnittger, I., Liang, D., Haddad, F. 2018


    Obtaining focused right ventricular (RV) apical view remains challenging using conventional two-dimensional (2D) echocardiography. This study main objective was to determine whether measurements from RV focused views derived from three-dimensional (3D) echocardiography (3D-RV-focused) are closely related to measurements from magnetic resonance (CMR). A first cohort of 47 patients underwent 3D echocardiography and CMR imaging within 2h of each other. A second cohort of 25 patients had repeat 3D echocardiography to determine the test-retest characteristics; and evaluate the bias associated with unfocused RV views. Tomographic views were extracted from the 3D dataset: RV focused views were obtained using the maximal RV diameter in the transverse plane, and unfocused views from a smaller transverse diameter enabling visualization of the tricuspid valve opening. Measures derived using the 3D-RV-focused view were strongly associated with CMR measurements. Among functional metrics, the strongest association was between RV fractional area change (RVFAC) and ejection fraction (RVEF) (r=0.92) while tricuspid annular plane systolic excursion moderately correlated with RVEF (r=0.47), all p<0.001. Among RV size measures, the strongest association was found between RV end-systolic area (RVESA) and volume (r=0.87, p<0.001). RV unfocused views led on average to 10% underestimation of RVESA. The 3D-RV-focused method had acceptable test-retest characteristics with a coefficient of variation of 10% for RVESA and 11% for RVFAC. Deriving standardized RV focused views using 3D echocardiography strongly relates to CMR-derived measures and may improve reproducibility in RV 2D measurements.

    View details for DOI 10.1007/s10554-018-1356-7

    View details for PubMedID 29654480

  • Value of Circulating Cytokine Profiling During Submaximal Exercise Testing in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Scientific reports Moneghetti, K. J., Skhiri, M., Contrepois, K., Kobayashi, Y., Maecker, H., Davis, M., Snyder, M., Haddad, F., Montoya, J. G. 2018; 8 (1): 2779


    Myalgic Encephalomyelitis or Chronic Fatigue Syndrome (ME/CFS) is a heterogeneous syndrome in which patients often experience severe fatigue and malaise following exertion. Immune and cardiovascular dysfunction have been postulated to play a role in the pathophysiology. We therefore, examined whether cytokine profiling or cardiovascular testing following exercise would differentiate patients with ME/CFS. Twenty-four ME/CFS patients were matched to 24 sedentary controls and underwent cardiovascular and circulating immune profiling. Cardiovascular analysis included echocardiography, cardiopulmonary exercise and endothelial function testing. Cytokine and growth factor profiles were analyzed using a 51-plex Luminex bead kit at baseline and 18 hours following exercise. Cardiac structure and exercise capacity were similar between groups. Sparse partial least square discriminant analyses of cytokine profiles 18 hours post exercise offered the most reliable discrimination between ME/CFS and controls (κ = 0.62(0.34,0.84)). The most discriminatory cytokines post exercise were CD40L, platelet activator inhibitor, interleukin 1-β, interferon-α and CXCL1. In conclusion, cytokine profiling following exercise may help differentiate patients with ME/CFS from sedentary controls.

    View details for DOI 10.1038/s41598-018-20941-w

    View details for PubMedID 29426834

    View details for PubMedCentralID PMC5807550

  • Athletic Remodeling in Female College Athletes, the "Morganroth Hypothesis" Revisited. Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine Kooreman, Z., Giraldeau, G., Finocchiaro, G., Kobayashi, Y., Wheeler, M., Perez, M., Moneghetti, K., Oxborough, D., George, K. P., Myers, J., Ashley, E., Haddad, F. 2018


    There is limited data regarding ventricular remodeling in college female athletes, especially when appropriate scaling of cardiac dimensions to lean body mass (LBM) is considered. Moreover, it is not well established whether cardiac remodeling in female athletes is a balanced process with proportional increase in left ventricular (LV) mass and volume or the right and LV size.During the preparticipation competitive screening, 72 female college athletes volunteered to undergo dual energy x-ray absorptiometry scan for quantification of LBM and comprehensive 2D echocardiography including assessment of longitudinal myocardial strain. The athletes were divided in 2 groups according to the intensity of the dynamic and static components of their sport categories, ie, a higher intensity dynamic and resistive group (n = 37 participating in rowing, water polo and lacrosse) and a lower intensity group (n = 35, participating in short distance running, sailing, synchronized swimming, and softball). In addition, we recruited a group of 31 age-matched nonathlete controls.The mean age of the study population was 18.7 ± 1.0 years. When scaled to body surface area, the higher intensity group had 17.1 ± 3.6% (P < 0.001) greater LV mass when compared with the lower intensity group and 21.7 ± 4.0% (P < 0.001) greater LV mass than the control group. The differences persisted after scaling to LBM with 14.2 ± 3.2% (P < 0.001) greater LV mass in the higher intensity group. By contrast, there was no difference in any of the relative remodeling indices including the LV mass to volume ratio, right to LV area ratio, or left atrial to LV volume ratio (P > 0.50 for all). In addition, no significant difference was noted among the 3 groups in LV ejection fraction (P = 0.22), LV global longitudinal strain (P = 0.55), LV systolic strain rate (P = 0.62), or right ventricular global longitudinal strain (P = 0.61).Female collegiate athletes participating in higher intensity dynamic and resistive sports have higher indexed LV mass even when scaled to LBM. The remodeling process does however appear to be a balanced process not only at the intraventricular level but also at the interventricular and atrioventricular levels.

    View details for DOI 10.1097/JSM.0000000000000501

    View details for PubMedID 29369833

  • Left atrial function and phenotypes in asymmetric hypertrophic cardiomyopathy. Echocardiography (Mount Kisco, N.Y.) Kobayashi, Y., Wheeler, M., Finocchiaro, G., Ariyama, M., Kobayashi, Y., Perez, M. V., Liang, D., Kuznetsova, T., Schnittger, I., Ashley, E., Haddad, F. 2017


    Few studies have analyzed changes in left atrial (LA) function associated with different phenotypes of asymmetric hypertrophic cardiomyopathy (HCM). We sought to demonstrate the association of impairments in LA function with disease phenotype in patients with obstructive and nonobstructive HCM.From Stanford Cardiomyopathy Registry, we randomly selected 50 age-/sex-matched healthy controls, 35 patients with nonobstructive HCM (HCM 1), 35 patients with obstructive HCM (HCM 2), and 35 patients with obstructive HCM requiring septal reduction therapy (HCM 3). Echocardiography was performed to evaluate left ventricular (LV) strain as well as LA function including LA emptying fraction and LA strain.The mean age was 51±14 years and 57% were male. LA volume index differed among all four predefined groups (25.6±6.7 mL/m(2) in controls, 32.2±13.3 mL/m(2) in HCM 1, 42.0±12.9 mL/m(2) in HCM 2, 52.4±15.2 mL/m(2) for HCM 3, and P<.05 all between groups). All measurement of LA function was impaired in patients with HCM than controls. Total and passive LA function was further impaired in HCM 2 or 3 compared with HCM 1, while active LA function was not different among the three groups. Among LV strains, only septal longitudinal strain differed among all groups (-18.5±1.9% in controls, -14.5±1.9% in HCM 1, -13.3±1.8% in HCM 2, -11.6±2.3% in HCM 3, and P<.05 all between groups).LA function was impaired in patients with HCM even in minimally symptomatic nonobstructive phenotype. Total and passive LA function was further impaired in patients with obstructive HCM.

    View details for DOI 10.1111/echo.13533

    View details for PubMedID 28370331

  • Additive value of nicorandil on ATP for further inducing hyperemia in patients with an intermediate coronary artery stenosis. Coronary artery disease Kobayashi, Y., Okura, H., Neishi, Y., Higa, T., Kobayashi, Y., Uemura, S., Yoshida, K. 2017; 28 (2): 104-109


    The induction of hyperemia is of importance to precisely assess the functional significance of coronary artery lesions with fractional flow reserve (FFR). Adenosine or ATP alone is used widely in this setting; however, little is known about the additive value of nicorandil, which acts as a nitrate and a K-ATP channel opener, to induce further hyperemia.A total of 183 intermediate native coronary artery lesions from 112 patients were prospectively enrolled into this study. FFR was measured using a coronary pressure wire during an intravenous ATP infusion alone (150 mcg/kg/min) (FFRATP) and repeated after an adjunctive intracoronary nicorandil injection (2.0 mg) (FFRATP+Nico).Physiologic measurements were completed without any severe adverse effects from ATP and nicorandil in all patients. FFRATP and FFRATP+Nico had a strong linear correlation (R=0.79, P<0.001). The FFR value became significantly lower with an adjunctive intracoronary nicorandil injection compared with ATP alone [FFRATP vs. FFRATP+Nico, 0.87 (interquartile range: 0.81-0.92) vs. 0.85 (0.79-0.90), P<0.001]. A total of 18 lesions out of 183 (9.8%) were reclassified after a nicorandil injection (12 from FFR>0.80 to ≤0.80 vs. six from FFR≤0.80 to >0.80, P=0.26). The adjunctive effect of nicorandil was accentuated with each increment of FFRATP strata (per 0.05 increase, P for trend<0.001), but with minimal effect around the borderline FFR zone.An adjunctive intracoronary nicorandil injection is safe, but appears to have little effect in inducing further hyperemia. Therefore, its effect on the clinical scenario is limited.

    View details for DOI 10.1097/MCA.0000000000000433

    View details for PubMedID 27611876

  • Incremental value of right heart metrics and exercise performance to well-validated risk scores in dilated cardiomyopathy. European heart journal cardiovascular Imaging Moneghetti, K. J., Giraldeau, G., Wheeler, M. T., Kobayashi, Y., Vrtovec, B., Boulate, D., Kuznetsova, T., Schnittger, I., Wu, J. C., Myers, J., Ashley, E., Haddad, F. 2017


    Risk stratification in heart failure (HF) relies on several established clinical risk scores, however, myocardial deformation, right heart metrics, and exercise performance have not usually been considered. This study sought to assess the incremental value of advanced echocardiographic and cardiopulmonary exercise testing (CPX) parameters to validated risk scores in HF.The Meta-Analysis Global Group in Chronic Heart Failure (MAGGIC) and Metabolic Exercise Test Data Combined with Cardiac and Kidney Indexes (MECKI) scores were applied to 208 ambulatory patients with dilated cardiomyopathy (DCM) who completed echocardiography in conjunction with CPX as part of the Stanford Exercise Testing registry. Patients were followed for the composite end point of death, heart transplant, left ventricular device implantation, and hospitalization for acute HF. Mean age, left ventricular ejection fraction (LVEF), and left ventricular global longitudinal strain (LVGLS) were 47 ± 13 years, 33 ± 13%, and -10.6 ± 4.4%, respectively, while right ventricular free-wall longitudinal strain was -18.8 ± 5.5%. Partial correlation mapping identified strong correlations between LVEF, LVGLS, and LV systolic strain rate, with a moderate correlation between these metrics and peak VO2. Over a median follow up of 5.3 years, the composite end point occurred in 60 patients. Cox proportional hazards identified MAGGIC score [hazard ratio (HR) (2.04 [1.39-3.01], P < 0.01], peak VO2 HR (0.52 [0.28-0.97], P = 0.04), and right atrial volume indexed (RAVI) HR (1.31 [1.07-1.61], P < 0.01) as independent correlates of outcome. RAVI remained an independent correlate when combined with the MECKI score (2.21 [1.59-3.07]), P < 0.01, RAVI, 1.33 [1.06-1.67], P = 0.01).Our study demonstrates that RAVI is complementary to well-validated HF risk scores and highlights the importance of exercise performance in DCM.

    View details for DOI 10.1093/ehjci/jex187

    View details for PubMedID 28977353

  • Value of Strain Imaging and Maximal Oxygen Consumption in Patients With Hypertrophic Cardiomyopathy. The American journal of cardiology Moneghetti, K. J., Stolfo, D., Christle, J. W., Kobayashi, Y., Finocchiaro, G., Sinagra, G., Myers, J., Ashley, E. A., Haddad, F., Wheeler, M. T. 2017; 120 (7): 1203–8


    Longitudinal strain (LS) has been shown to be predictive of outcome in hypertrophic cardiomyopathy (HC). Percent predicted peak oxygen uptake (ppVO2), among other cardiopulmonary exercise testing (CPX) metrics, is a strong predictor of prognosis in HC. However, there has been limited investigation into the combination of LS and CPX metrics. This study sought to determine how LS and parameters of exercise performance contribute to prognosis in HC. One hundred and thirty-one consecutive patients with HC who underwent CPX and stress echocardiography were included. Global, septal, and lateral LS were assessed at rest and stress. Eighty matched individuals were used as controls. Patients were followed for the composite end point of death and worsening heart failure. All absolute LS components were lower in patients with HC than in controls (global 14.3 ± 4.0% vs 18.8 ± 2.2%, p <0.001; septal 11.9 ± 4.9% vs 17.9 ± 2.7%, p <0.001; lateral 16.0 ± 4.7% vs 19.4 ± 3.1%, p = 0.001). Global strain reserve was also reduced in patients with HC (13 ± 5% vs 19 ± 8%, p = 0.002). Over a median follow-up of 56 months (interquartile range 14 to 69), the composite end point occurred in 53 patients. Global LS was predictive of outcome on univariate analysis (0.55 [0.41 to 0.74], p <0.001). When combined with CPX metrics, lateral LS was the only strain variable predictive of outcome along with indexed left atrial volume (LAVI) and ppVO2. The worst outcomes were observed for patients with lateral LS <16.1%, LAVI >52 ml/m2, and ppVO2 <80%. The combination of lateral LS, LAVI, and ppVO2 presents a simple model for outcome prediction.

    View details for DOI 10.1016/j.amjcard.2017.06.070

    View details for PubMedID 28802509

  • Functional Cardiac Recovery and Hematologic Response to Chemotherapy in Patients With Light-Chain Amyloidosis (from the Stanford University Amyloidosis Registry). The American journal of cardiology Tuzovic, M., Kobayashi, Y., Wheeler, M., Barrett, C., Liedtke, M., Lafayette, R., Schrier, S., Haddad, F., Witteles, R. 2017; 120 (8): 1381–86


    Cardiac involvement is common in patients with light-chain (AL) amyloidosis and portends a poor prognosis, although little is known about the changes in cardiac mechanics after chemotherapy. We sought to explore the relation between amyloidosis staging and baseline cardiac mechanics and to investigate short-term changes in cardiac mechanics after chemotherapy. We identified 41 consecutive patients from the Stanford Amyloid Center who had echocardiograms and free light-chain values before and after chemotherapy, along with 40 age- and gender-matched controls. Echocardiographic assessment included left ventricular global longitudinal strain, E/e' ratio, and left atrial (LA) stiffness. Hematologic response to chemotherapy was defined as ≥50% reduction in the difference between the involved and the uninvolved free light chain (dFLC). The mean age was 66.9 ± 8.4 years and 66% were men. Before chemotherapy, global longitudinal strain, E/e' ratio, and LA stiffness were impaired in patients with amyloidosis compared with controls, and the severity of impairment worsened with advanced staging. After chemotherapy, hematologic response was observed in 30 (73%) patients. There was a significant association between the change in dFLC and cardiac function (E/e' ratio: r = -0.43, p = 0.01; LA stiffness: r = -0.35, p = 0.05). There was no significant improvement in cardiac mechanics in patients without a hematologic response to chemotherapy. In conclusion, amyloidosis stage correlated with noninvasive measurements of cardiac mechanics, and improvement in dFLC correlated with cardiac improvement on short-term follow-up echocardiography.

    View details for DOI 10.1016/j.amjcard.2017.07.025

    View details for PubMedID 28844519

  • Contractile reserve and cardiopulmonary exercise parameters in patients with dilated cardiomyopathy, the two dimensions of exercise testing. Echocardiography (Mount Kisco, N.Y.) Moneghetti, K. J., Kobayashi, Y., Christle, J. W., Ariyama, M., Vrtovec, B., Kouznetsova, T., Wilson, A., Ashley, E., Wheeler, M. T., Myers, J., Haddad, F. 2017


    Left ventricular (LV) contractile reserve assessed using imaging and cardiopulmonary exercise testing (CPX) has been shown to predict outcome in patients with dilated cardiomyopathy (DCM). Few clinical studies have, however, analyzed the relationship between them.A cohort of 75 ambulatory patients with DCM underwent stress treadmill echocardiography with CPX. LV contractile reserve was calculated as absolute change (ΔLVEF=LVEFpeak -LVEFrest ) and percent change (%LVEF=[(LVEFpeak -LVEFrest )/LVEFpeak) ]×100) in LVEF, circumferential and longitudinal strain (LS). Exercise capacity was measured as peak oxygen uptake (peak VO2 ) and ventilatory efficiency as the slope of minute ventilation to CO2 production (VE/VCO2 slope). Values of contractile reserve were compared to matched controls. We also explored which metric of ventricular response (absolute or percent change) was less dependent on baseline LV function.Patients with DCM had a mean age, rest and peak LVEF of 44±10 years, 42±10% and 50±12%, respectively. Among parameters of contractile reserve, peak cardiac output was the strongest parameter associated with peak VO2 (r=.63, P<.001). Along with age, sex, and BMI, it explained more than 70% of the variance in peak VO2 . In contrast, LVEF and LS were only weakly related to peak VO2 . With regard to ventilatory efficiency, the strongest parameter that emerged was right atrial volume index (r=.36, P<.001). Percent change in LVEF was more independent of baseline function than absolute change.Echocardiographic contractile reserve and CPX provide complementary information. Percent change in contractile reserve was most independent of baseline function, therefore may be preferred when analyzing the ventricular response to exercise.

    View details for DOI 10.1111/echo.13623

    View details for PubMedID 28681553

  • GDF-15 (Growth Differentiation Factor 15) Is Associated With Lack of Ventricular Recovery and Mortality After Transcatheter Aortic Valve Replacement. Circulation. Cardiovascular interventions Kim, J. B., Kobayashi, Y., Moneghetti, K. J., Brenner, D. A., O'Malley, R., Schnittger, I., Wu, J. C., Murtagh, G., Beshiri, A., Fischbein, M., Miller, D. C., Liang, D., Yeung, A. C., Haddad, F., Fearon, W. F. 2017; 10 (12)


    Recent data suggest that circulating biomarkers may predict outcome in patients undergoing transcatheter aortic valve replacement (TAVR). We examined the association between inflammatory, myocardial, and renal biomarkers and their role in ventricular recovery and outcome after TAVR.A total of 112 subjects undergoing TAVR were included in the prospective registry. Plasma levels of B-type natriuretic peptide, hs-TnI (high-sensitivity troponin I), CRP (C-reactive protein), GDF-15 (growth differentiation factor 15), GAL-3 (galectin-3), and Cys-C (cystatin-C) were assessed before TAVR and in 100 sex-matched healthy controls. Among echocardiographic parameters, we measured global longitudinal strain, indexed left ventricular mass, and indexed left atrial volume. The TAVR group included 59% male, with an average age of 84 years, and 1-year mortality of 18%. Among biomarkers, we found GDF-15 and CRP to be strongly associated with all-cause mortality (P<0.001). Inclusion of GDF-15 and CRP to the Society of Thoracic Surgeons score significantly improved C index (0.65-0.79; P<0.05) and provided a category-free net reclassification improvement of 106% at 2 years (P=0.01). Among survivors, functional recovery in global longitudinal strain (>15% improvement) and indexed left ventricular mass (>20% decrease) at 1 year occurred in 48% and 22%, respectively. On multivariate logistic regression, lower baseline GDF-15 was associated with improved global longitudinal strain at 1 year (hazard ratio=0.29; P<0.001). Furthermore, improvement in global longitudinal strain at 1 month correlated with lower overall mortality (hazard ratio=0.45; P=0.03).Elevated GDF-15 correlates with lack of reverse remodeling and increased mortality after TAVR and improves risk prediction of mortality when added to the Society of Thoracic Surgeons score.

    View details for DOI 10.1161/CIRCINTERVENTIONS.117.005594

    View details for PubMedID 29222133

  • Impact of Septal Reduction on Left Atrial Size and Diastole in Hypertrophic Cardiomyopathy ECHOCARDIOGRAPHY-A JOURNAL OF CARDIOVASCULAR ULTRASOUND AND ALLIED TECHNIQUES Finocchiaro, G., Haddad, F., Kobayashi, Y., Lee, D., Pavlovic, A., Schnittger, I., Sinagra, G., Magavern, E., Myers, J., Froelicher, V., Knowles, J. W., Ashley, E. 2016; 33 (5): 686-694


    Both myectomy and alcohol septal ablation (ASA) can substantially reduce left ventricular (LV) outflow obstruction, relieve symptoms, and improve outcomes in hypertrophic cardiomyopathy (HCM). It is unclear whether septal reduction decreases left atrial (LA) size and improves diastolic function. The aim of this study was to analyze the consequences of septal reduction on LA size and diastolic function in a cohort of patients with HCM.Forty patients (mean age: 50 ± 14, male sex 64%) with HCM who underwent septal reduction (myectomy or alcohol septal ablation) were studied. Retrospective analyses of echocardiograms preprocedure, postprocedure, and at 1 year of follow-up were performed.Thirty-one patients had septal myectomy and 9 ASA. The degree of reduction in rest peak LV outflow tract gradient was significant (57 ± 32 vs. 23 ± 20 mmHg at 1 year, P < 0.001). Maximal interventricular septal thickness decreased from 22 ± 6 mm preprocedure to 19 ± 4 mm postprocedure (P < 0.001); moderate-to-severe mitral regurgitation (MR) was initially present in 34% of the sample and only 2% after the procedure. Average LA volume index (LAVI) decreased from 63 ± 20 to 55 ± 20 mL/m(2) at the 1-year follow-up (P < 0.001). We did not observe a significant improvement in diastolic function at Doppler (E/A 1.2 ± 0.4 vs. 1.1 ± 0.5, P = 0.07; E' 7.6 ± 3.6 vs. 6.9 ± 3.0, P = 0.4) pre- and postprocedure, respectively). At 1 year, only 5% of the patients were severely symptomatic (NYHA III). On multivariate analysis, a significant change in the LVOT gradient during stress (Δ gradient ≥30 mmHg) was the only variable independently associated with LAVI reverse remodeling >10 mL/m(2) [OR = 6.4 (CI 95% 1.12-36.44), P = 0.04].Septal reduction is effective in the relief of LV obstruction and symptoms in patients with HCM. The hemodynamic changes result in a significant LA reverse remodeling, but not in an improvement of diastolic function in these patients.

    View details for DOI 10.1111/echo.13158

    View details for Web of Science ID 000375933100004

    View details for PubMedID 26926154

  • Regional right ventricular dysfunction in acute pulmonary embolism: relationship with clot burden and biomarker profile INTERNATIONAL JOURNAL OF CARDIOVASCULAR IMAGING Tuzovic, M., Adigopula, S., Amsallem, M., Kobayashi, Y., Kadoch, M., Boulate, D., Krishnan, G., Liang, D., Schnittger, I., Fleischmann, D., McConnell, M. V., Haddad, F. 2016; 32 (3): 389-398


    Regional right ventricular (RV) dysfunction (RRVD) is an echocardiographic feature in acute pulmonary embolism (PE), primarily reported in patients with moderate-to-severe RV dysfunction. This study investigated the clinical importance of RRVD by assessing its relationship with clot burden and biomarkers. We identified consecutive patients admitted to the emergency department between 1999 and 2014 who underwent computed tomographic angiography, echocardiography, and biomarker testing (troponin and NT-proBNP) for suspected acute PE. RRVD was defined as normal excursion of the apex contrasting with hypokinesis of the mid-free wall segment. RV assessment included measurements of ventricular dimensions, fractional area change, free-wall longitudinal strain and tricuspid annular plane systolic excursion. Clot burden was assessed using the modified Miller score. Of 82 patients identified, 51 had acute PE (mean age 66 ± 17 years, 43 % male). No patient had RV myocardial infarction. RRVD was present in 41 % of PEs and absent in all patients without PE. Among patients with PE, 86 % of patients with RRVD had central or multi-lobar PE. Patients with RRVD had higher prevalence of moderate-to-severe RV dilation (81 vs. 30 %, p < 0.01) and dysfunction (86 vs. 23 %, p < 0.01). There was a strong trend for higher troponin level in PE patients with RRVD (38 vs. 13 % in PE patients without RRVD, p = 0.08), while there was no significant difference for NT-proBNP (67 vs. 73 %, p = 0.88). RRVD showed good concordance between readers (87 %). RRVD is associated with an increased clot burden in acute PE and is more prevalent among patients with moderate-to-severe RV enlargement and dysfunction.

    View details for DOI 10.1007/s10554-015-0780-1

    View details for Web of Science ID 000370166100003

    View details for PubMedID 26428674

  • Comparison of left ventricular manual versus automated derived longitudinal strain: implications for clinical practice and research INTERNATIONAL JOURNAL OF CARDIOVASCULAR IMAGING Kobayashi, Y., Ariyama, M., Kobayashi, Y., Giraldeau, G., Fleischman, D., Kozelj, M., Vrtovec, B., Ashley, E., Kuznetsova, T., Schnittger, I., Liang, D., Haddad, F. 2016; 32 (3): 429-437


    Systolic global longitudinal strain (GLS) is emerging as a useful metric of ventricular function in heart failure and usually assessed using post-processing software. The purpose of this study was to investigate whether longitudinal strain (LS) derived using manual-tracings of ventricular lengths (manual-LS) can be reliable and time efficient when compared to LS obtained by post-processing software (software-LS). Apical 4-chamber view images were retrospectively examined in 50 healthy controls, 100 patients with dilated cardiomyopathy (DCM), and 100 with hypertrophic cardiomyopathy (HCM). We measured endocardial and mid-wall manual-LS and software-LS, using peak of average regional curve [software-LS(a)] and global ventricular lengths [software-LS(l)] according to definition of Lagragian strain. We compared manual-LS and software-LS by using Bland-Altman plot and coefficient of variation (COV). In addition, test-retest was also performed for further assessment of variability in measurements. While manual-LS was obtained in all subjects, software-LS could be obtained in 238 subjects (95 %). The time spent for obtaining manual-LS was significantly shorter than for the software-LS (94 ± 39 s vs. 141 ± 79 s, P < 0.001). Overall, manual-LS had an excellent correlation with both software-LS (a) (R(2) = 0.93, P < 0.001) and software-LS(l) (R(2) = 0.84, P < 0.001). The bias (95 %CI) between endocardial manual-LS and software-LS(a) was 0.4 % [-2.8, 3.6 %] in absolute and 3.5 % [-17.0, 24.0 %] in relative difference while it was 0.4 % [-2.5, 3.3 %] and 3.4 % [-16.2, 23.1 %], respectively with software-LS(l). Mid-wall manual-LS and mid-wall software-LS(a) also had good agreement [a bias (95 % CI) for absolute value of 0.1 % [-2.1, 2.5 %] in HCM, and 0.2 % [-2.2, 2.6 %] in controls]. The COV for manual and software derived LS were below 6 %. Test-retest showed good variability for both methods (COVs were 5.8 and 4.7 for endocardial and mid-wall manual-LS, and 4.6 and 4.9 for endocardial and mid-wall software-LS(a), respectively. Manual-LS appears to be as reproducible as software-LS; this may be of value especially when global strain is the metric of interest.

    View details for DOI 10.1007/s10554-015-0804-x

    View details for Web of Science ID 000370166100008

    View details for PubMedID 26578468

  • Addressing the Controversy of Estimating Pulmonary Arterial Pressure by Echocardiography JOURNAL OF THE AMERICAN SOCIETY OF ECHOCARDIOGRAPHY Amsallem, M., Sternbach, J. M., Adigopula, S., Kobayashi, Y., Vu, T. A., Zamanian, R., Liang, D., Dhillon, G., Schnittger, I., McConnell, M. V., Haddad, F. 2016; 29 (2): 93-102


    There is currently controversy over whether echocardiography provides reliable estimations of pulmonary pressures. The objective of this study was to determine the factors influencing the accuracy and reliability of estimating right ventricular systolic pressure (RVSP) using echocardiography in patients with advanced lung disease or pulmonary arterial hypertension.Between January 2001 and December 2012, 667 patients with advanced lung disease or pulmonary arterial hypertension underwent right heart catheterization and transthoracic echocardiography. Of those, 307 had both studies within 5 days of each other. The correlation and bias in estimating RVSP according to tricuspid regurgitation (TR) signal quality and reader expertise were retrospectively determined. Reasons for under- and overestimation were analyzed. The diagnostic performance of estimated RVSP, relative right ventricular size, eccentricity index, and tricuspid annular plane systolic excursion was compared for classifying patients with pulmonary hypertension (mean pulmonary artery pressure ≥ 25 mm Hg).Invasive mean and systolic pulmonary artery pressures were strongly correlated (R(2) = 0.95, P < .001), with mean pulmonary artery pressure = 0.60 × systolic pulmonary artery pressure + 2.1 mm Hg. Among patients undergoing right heart catheterization and transthoracic echocardiography within 5 days, level 3 readers considered only 61% of TR signals interpretable, compared with 72% in clinical reports. Overestimation in the clinical report was related mainly to not assigning peak TR velocity at the modal frequency and underestimation to overreading of uninterpretable signals. When the TR signal was interpretable, the areas under the curve for classifying pulmonary hypertension were 0.97 for RVSP and 0.98 for RVSP and eccentricity index (P > .05). When TR signals were uninterpretable, eccentricity index and right ventricular size were independently associated with pulmonary hypertension (area under the curve, 0.77).Echocardiography reliably estimates RVSP when attention is given to simple quality metrics.

    View details for DOI 10.1016/j.echo.2015.11.001

    View details for Web of Science ID 000369168700003

  • Gender Differences in Ventricular Remodeling and Function in College Athletes, Insights from Lean Body Mass Scaling and Deformation Imaging AMERICAN JOURNAL OF CARDIOLOGY Giraldeau, G., Kobayashi, Y., Finocchiaro, G., Wheeler, M., Perez, M., Kuznetsova, T., Lord, R., George, K. P., Oxborough, D., Schnittger, T., Froelicher, V., Liang, D., Ashley, E., Haddad, F. 2015; 116 (10): 1610-1616


    Several studies suggest gender differences in ventricular dimensions in athletes. Few studies have, however, made comparisons of data indexed for lean body mass (LBM) using allometry. Ninety Caucasian college athletes (mixed sports) who were matched for age, ethnicity, and sport total cardiovascular demands underwent dual-energy x-ray absorptiometry scan for quantification of LBM. Athletes underwent comprehensive assessment of left and right ventricular and atrial structure and function using 2-dimensional echocardiography and deformation imaging using the TomTec analysis system. The mean age of the study population was 18.9 ± 1.9 years. Female athletes (n = 45) had a greater fat free percentage (19.4 ± 3.7%) compared to male athletes (11.5 ± 3.7%). When scaled to body surface area, male had on average 19 ± 3% (p <0.001) greater left ventricular (LV) mass; in contrast, when scaled to LBM, there was no significant difference in indexed LV mass -1.4 ± 3.0% (p = 0.63). Similarly, when allometrically scaled to LBM, there was no significant gender-based difference in LV or left atrial volumes. Although female athletes had mildly higher LV ejection fraction and LV global longitudinal strain in absolute value, systolic strain rate and allometrically indexed stroke volume were not different between genders (1.5 ± 3.6% [p = 0.63] and 0.0 ± 3.7% [p = 0.93], respectively). There were no differences in any of the functional atrial indexes including strain or strain rate parameters. In conclusion, gender-related differences in ventricular dimensions or function (stroke volume) appear less marked, if not absent, when indexing using LBM allometrically.

    View details for DOI 10.1016/j.amjcard.2015.08.026

    View details for Web of Science ID 000365151100021

    View details for PubMedID 26456207

  • Exercise Strain Echocardiography in Patients With a Hemodynamically Significant Myocardial Bridge Assessed by Physiological Study. Journal of the American Heart Association Kobayashi, Y., Tremmel, J. A., Kobayashi, Y., Amsallem, M., Tanaka, S., Yamada, R., Rogers, I. S., Haddad, F., Schnittger, I. 2015; 4 (11)


    Although a myocardial bridge (MB) is often regarded as a benign coronary variant, recent studies have associated MB with focal myocardial ischemia. The physiological consequences of MB on ventricular function during stress have not been well established.We enrolled 58 patients with MB of the left anterior descending artery, diagnosed by intravascular ultrasound. Patients underwent invasive physiological evaluation of the MB by diastolic fractional flow reserve during dobutamine challenge and exercise echocardiography. Septal and lateral longitudinal strain (LS) were assessed at rest and immediately after exercise and compared with strain of matched controls. Absolute and relative changes in strain were also calculated. The mean age was 42.5±16.0 years. Fifty-five patients had a diastolic fractional flow reserve ≤0.76. At rest, there was no significant difference between the 2 groups in septal LS (19.0±1.8% for patients with MB versus 19.2±1.5% for control, P=0.53) and lateral LS (20.1±2.0% versus 20.0±1.6%, P=0.83). With stress, compared with controls, patients with MB had a lower peak septal LS (18.9±2.6% versus 21.7±1.6%, P<0.001) and lower absolute (-0.1±2.1% versus 2.5±1.3%, P<0.001) and relative change (-0.6±11.2% versus 13.1±7.8%, P<0.001) in septal LS, whereas there was no significant difference in lateral LS. In multivariate analysis, diastolic fractional flow reserve and length were independent determinants of lower changes in septal LS.Patients with a hemodynamically significant MB, determined by invasive diastolic fractional flow reserve, have significantly lower change in septal LS on exercise echocardiography, suggesting that septal LS may be useful for noninvasively assessing the hemodynamic significance of an MB.

    View details for DOI 10.1161/JAHA.115.002496

    View details for PubMedID 26581225

  • Prognostic utility of right atrial emptying fractions in pulmonary arterial hypertension. Pulmonary circulation Brunner, N. W., Haddad, F., Kobayashi, Y., Hsi, A., Swiston, J. R., Gin, K. G., Zamanian, R. T. 2015; 5 (3): 473-480


    Although left atrial function has been extensively studied in patients with heart failure, the determinants and clinical correlates of impaired right atrial (RA) function have been poorly studied. We investigated measures of RA function in pulmonary arterial hypertension (PAH). We identified all treatment-naive patients with World Health Organization category 1 PAH seen at our center during 2000-2011 who had right heart catheterization and 6-minute walk test (6MWT) within 1 month of initial echocardiographic examination. Atrial size was measured using the monoplane area-length method, and atrial function was quantified using total, passive, and active RA emptying fractions (RAEFs). We compared measures of RAEF with known prognostic clinical, echocardiographic, and hemodynamic parameters. For the subset of patients with follow-up echocardiographic examination/6MWT within 6-18 months, we investigated the change in RAEF. In an exploratory analysis, we investigated the association between RAEF and mortality. Our population consisted of 39 patients with treatment-naive (incident) PAH, 30 of whom had follow-up testing. The mean total, passive, and active RAEFs were 24.4% ± 15.1%, 8.5% ± 6.9%, and 17.6% ± 13.9%, respectively. Total and active RAEFs correlated with tricuspid annular plane systolic excursion (P = 0.004 and P = 0.005) and cardiac output (P = 0.02 and P = 0.01). The change in active RAEF correlated with change in 6-minute walk distance (P = 0.02). In our Cox regression analysis, low active and total RAEF were associated with mortality, with hazard ratios of 5.6 (95% confidence interval [CI], 1.2-26.2; P = 0.03) and 4.2 (95% CI, 1.1-15.5; P = 0.03), respectively. Passive RAEF was poorly reproducible and not associated with outcome. Measures of RAEF appear to have prognostic importance in PAH and warrant further study.

    View details for DOI 10.1086/682218

    View details for PubMedID 26401248

    View details for PubMedCentralID PMC4556498

  • Direct relationship of local C-reactive protein production and lipid pool characterized by integrated backscatter intravascular ultrasound: a preliminary observation CORONARY ARTERY DISEASE Kobayashi, Y., Okura, H., Kume, T., Miyamoto, Y., Yamada, R., Kobayashi, Y., Fukuhara, K., Koyama, T., Neishi, Y., Yoshida, K. 2015; 26 (5): 425-431


    Local production of C-reactive protein (CRP) in human coronary arterial plaque was reported as a possible marker for local inflammation and vulnerable plaque. Integrated backscatter intravascular ultrasound (IB-IVUS) plaque tissue characterization may detect vulnerable plaque with high local plaque inflammation. Thus, the aim of this study was to clarify the relationship between IB-IVUS-based plaque characteristics and local high-sensitivity C-reactive protein (hs-CRP) production in stable and unstable plaque.Eighteen patients (nine unstable angina/non-ST-segment elevation myocardial infarction and nine stable angina) were prospectively enrolled. Using the microcatheter, blood samples from the proximal and distal sites of the culprit lesion were obtained to measure local CRP production. Translesional hs-CRP was defined as distal hs-CRP minus proximal hs-CRP of the culprit lesion. Gray-scale and IB-IVUS analyses were carried out at the target lesion. The translesional hs-CRP level tended to be higher in the unstable angina group than in the stable angina group (0.026±0.033 vs. 0.003±0.007 mg/dl, P=0.050). Gray-scale IVUS-derived indices did not correlate with translesional hs-CRP. However, % lipid pool area by IB-IVUS correlated positively (r=0.54, P=0.02) and % fibrosis area correlated negatively with the translesional hs-CRP level (r=-0.52, P=0.03).Lipid pool area detected by IB-IVUS is correlated positively with the translesional hs-CRP level.

    View details for DOI 10.1097/MCA.0000000000000250

    View details for Web of Science ID 000357641400010

    View details for PubMedID 25886998

  • Prevalence and Prognostic Role of Right Ventricular Involvement in Stress-Induced Cardiomyopathy JOURNAL OF CARDIAC FAILURE Finocchiaro, G., Kobayashi, Y., Magavern, E., Zhou, J. Q., Ashley, E., Sinagra, G., Schnittger, I., Knowles, J. W., Fearon, W. F., Haddad, F., Tremmel, J. A. 2015; 21 (5): 419-425


    Stress-induced cardiomyopathy (SCM) is a reversible cardiomyopathy observed in patients without significant coronary disease. The aim of this study was to assess the incidence and clinical significance of right ventricular (RV) involvement in SCM.We retrospectively analyzed echocardiograms from 40 consecutive patients who presented with SCM at Stanford University Medical Center from September 2000 to November 2010. The primary end point was overall mortality. RV involvement was observed in 20 patients (50%; global RV hypokinesia in 15 patients and focal RV apical akinesia in 5 patients). The independent correlates of RV involvement were older age (odds ratio [OR] 1.09, 95% confidence interval [CI] 1.02-1.7two, P = .01) and LVEF (per 10% decrease: OR 3.60, CI 1.77-7.32; P = .02). At a mean follow-up of 44 ± 32 months, 12 patients (30%) died (in-hospital death in 3 patients). At multivariate analysis, the presence of an RV fractional area change <35% emerged as an independent predictor of death (OR 3.6, CI 1.06-12.41; P = .04).RV involvement is a common finding in SCM, and may present as either global or focal RV apical involvement. Both older age and lower LVEF are associated with a higher risk of RV involvement, which appears to be a major predictor of death.

    View details for DOI 10.1016/j.cardfail.2015.02.001

    View details for Web of Science ID 000354420600008

    View details for PubMedID 25704104

  • Impact of Target Lesion Coronary Calcification on Stent Expansion - An Optical Coherence Tomography Study CIRCULATION JOURNAL Kobayashi, Y., Okura, H., Kume, T., Yamada, R., Kobayashi, Y., Fukuhara, K., Koyama, T., Nezuo, S., Neishi, Y., Hayashida, A., Kawamoto, T., Yoshida, K. 2014; 78 (9): 2209-2214
  • Acute myocardial infarction after Kawasaki disease. JACC. Cardiovascular interventions Kobayashi, Y., Kobayashi, Y., Hirohata, A. 2014; 7 (7): e77-8

    View details for DOI 10.1016/j.jcin.2013.10.030

    View details for PubMedID 25060031

  • Pheochromocytoma found in takotsubo cardiomyopathy patients. journal of invasive cardiology Kobayashi, Y., Kobayashi, Y., Hirohata, A. 2014; 26 (6): E76-7


    Increased level of serum catecholamines in the acute phase was reported to be a feature of takotsubo cardiomyopathy (TC). We report a TC case with pheochromocytoma, which caused a stir in the diagnosis of TC and suggests the importance of screening for a catecholamine-producing tumor. A female patient was referred to our emergency department due to ongoing chest pain. Coronary angiography showed no abnormality; however, subsequent left ventriculography showed basal hyperkinesis and apical ballooning, which completely recovered in 2 weeks. She experienced significant emotional stress on the eve of her admission, to which the diagnosis of TC was attributed. Although serum catecholamine levels on admission in our case were higher than on day 14, the value on day 14 was much higher than the normal range in our patient. The screening abdominal computed tomography scan revealed a left adrenal mass, which was diagnosed as pheochromocytoma by 24-hour urinary excretion of catecholamine and (131)I-MIBG scintigraphy. The mass was successfully resected and pathological findings supported the diagnosis. In our case, emotional stress was thought to be the direct trigger to develop TC by exceeding the threshold of catecholamine-induced cardiomyopathy. Screening for a catecholamine-producing tumor through careful history-taking and measuring catecholamines at a follow-up stage were important clinical aspects in this case and may well be for others.

    View details for PubMedID 24907091

  • Left Main Coronary Thrombotic Occlusion Due to Secondary Polycythemia in a Normal Sinus of Valsalva JOURNAL OF INVASIVE CARDIOLOGY Kobayashi, Y., Kobayashi, Y., Hirohata, A. 2013; 25 (8): 421-422


    A case of acute myocardial infarction (AMI) due to thrombus in the left coronary cusp to the ascending aorta is described. There was no clinical evidence of coagulopathy, immunodisability, or local erosive lesion of the aortic and sinus of Valsalva wall macroscopically. Secondary polycythemia, induced by heavy smoking, was the likely cause of the myocardial infarction. Although this may be a rare case, intraaortic thrombus should be considered in the differential diagnosis of the causes of AMI.

    View details for Web of Science ID 000324872700018

    View details for PubMedID 23913610

  • Effectiveness of RAAS blocker in hypertension Yakkyoku Kobayashi, Y., Shimizu, I. 2011: 3872–3876
  • Successful catheter ablation to accessory atrioventricular pathway as cardiac resynchronization therapy in a patient with dilated cardiomyopathy EUROPACE Iwasaku, T., Hirooka, K., Taniguchi, T., Hamano, G., Utsunomiya, Y., Nakagawa, A., Koide, M., Ishizu, T., Yamato, M., Sasaki, N., Yamamoto, H., Kawaguchi, Y., Mizuno, H., Koretsune, Y., Kusuoka, H., Yasumura, Y. 2009; 11 (1): 121-123


    A 55-year-old man was admitted to our hospital for further examination of the abnormalities of chest X-ray and electrocardiogram. He was diagnosed with type B Wolff-Parkinson-White syndrome concomitant with dilated cardiomyopathy. Despite the medical therapy using enalapril and carvedilol for 20 months, his cardiac performance and brain natriuretic peptide (BNP) were not so improved. Because asynchronous septal motion caused by pre-excitation through a right-sided accessory pathway (AP) might deteriorate his cardiac performance, catheter ablation to the AP was performed. Successful procedure after 17 months improved left ventricular (LV) contraction, reduced LV volume, and decreased mitral regurgitation and BNP.

    View details for DOI 10.1093/europace/eun318

    View details for Web of Science ID 000261894200025

    View details for PubMedID 19028709

  • Structure and expression of a novel human FGF, FGF-19, expressed in the fetal brain BIOCHIMICA ET BIOPHYSICA ACTA-GENE STRUCTURE AND EXPRESSION Nishimura, T., Utsunomiya, Y., Hoshikawa, M., Ohuchi, H., Itoh, N. 1999; 1444 (1): 148-151

    View details for Web of Science ID 000078601000019

    View details for PubMedID 9931477