Clinical Focus

  • Internal Medicine

Education & Certifications

  • Medical Education:Case Western Reserve School of Medicine (2011) OH
  • Board Certification: Internal Medicine, American Board of Internal Medicine (2014)
  • Residency:Stanford University Hospital -Clinical Excellence Research Center (2014) CA

2017-18 Courses

All Publications

  • Reply to "heart failure and breast cancer: emerging controversies regarding some cardioprotective strategies". Journal of cardiac failure Witteles, R. M., Thakur, A. 2014; 20 (6): 457-?

    View details for DOI 10.1016/j.cardfail.2014.04.015

    View details for PubMedID 24747785

  • Usefulness of elevated urine neopterin levels in assessing cardiac dysfunction and exercise ventilation inefficiency in patients with chronic systolic heart failure. American journal of cardiology Shao, Z., Zhang, R., Shrestha, K., Borowski, A. G., Schuster, A., Thakur, A., Hazen, S. L., Tang, W. H. 2014; 113 (11): 1839-1843


    Neopterin is synthesized by macrophages upon stimulation with gamma-interferon, and high neopterin production is associated with cellular immune activation and increased production of reactive oxygen species (oxidant stress), but the clinical utility of urine neopterin levels in patients with heart failure (HF) has not been explored. Fifty-three ambulatory patients with chronic systolic HF (left ventricular [LV] ejection fraction ≤40%) underwent comprehensive echocardiographic evaluation and cardiopulmonary exercise testing. Urine neopterin levels were quantified by liquid chromatography with tandem mass spectrometric analyses and corrected to urine creatinine (Cr) levels. In our study cohort, median urine neopterin level was 60 μmol/mol Cr (interquartile range 40 to 86). There were modest correlations between urine neopterin levels and abnormalities in cardiac structure and function by echocardiography: LV ejection fraction (r = -0.33, p = 0.017), indexed LV end-diastolic volume (r = 0.31, p = 0.029), indexed LV end-systolic volume (r = 0.32, p = 0.024), and E/septal Ea (r = 0.28, p = 0.041). Although there was no significant correlation between urine neopterin and maximal oxygen uptake (peak VO2: r = -0.25, p = 0.07), there was a modest correlation between urine neopterin and maximal ventilation/carbon dioxide production ratio (VE/VCO2 max: r = 0.38, p = 0.005). In conclusion, increase in urine neopterin levels tracks with disease severity in patients with chronic systolic HF.

    View details for DOI 10.1016/j.amjcard.2014.03.016

    View details for PubMedID 24837262

  • Cancer therapy-induced left ventricular dysfunction: interventions and prognosis. Journal of cardiac failure Thakur, A., Witteles, R. M. 2014; 20 (3): 155-158


    For multiple chemotherapeutics, cardiotoxicity is dose limiting and can lead to substantial morbidity and mortality. Early cardiac intervention has the potential to positively affect clinical course.We reviewed 247 consecutive patients referred to the Stanford cardiology clinic for cancer therapy-associated cardiac abnormalities from 2004 to 2012. A comprehensive review of records was performed, with documentation of baseline characteristics, cardiac imaging, medications, and clinical course. Seventy-nine patients who had left ventricular ejection fraction (LVEF) declines temporally associated with cancer therapy were included. The most common malignancies were breast (46%) and hematologic (35%); 71% of the patients were female, and overall mean age was 52 years. The primary cancer therapeutics associated with LVEF decline included anthracyclines, trastuzumab, and tyrosine kinase inhibitors. The mean LVEF was 60% before cancer therapy and 40% after cancer therapy. The most common cardiac interventions included beta-blockers (84%) and angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (83%). Mean LVEF after cardiac intervention rose to 53%; 77% of patients had LVEF recovery to ≥50%, and 68% of these patients had recovery within 6 months of starting cardiac therapy; 76% of patients were able to continue their planned cancer therapy.With appropriate cardiac intervention, the majority of patients with LVEF decline from cancer therapy can achieve LVEF recovery and complete their cancer therapy.

    View details for DOI 10.1016/j.cardfail.2013.12.018

    View details for PubMedID 24378722

  • Increased Exhaled Nitric Oxide Levels After Exercise in Patients With Chronic Systolic Heart Failure With Pulmonary Venous Hypertension JOURNAL OF CARDIAC FAILURE Schuster, A., Thakur, A., Wang, Z., Borowski, A. G., Thomas, J. D., Tang, W. H. 2012; 18 (10): 799-803


    Fractional exhaled nitric oxide (eNO) is recognized as a marker of pulmonary endothelial function. Oxidative stress is associated with systemic endothelial nitric oxide production, but its correlation with eNO in heart failure (HF) patients has not been described. Previous studies have reported increased eNO levels after exercise in symptomatic HF patients but decreased levels with pulmonary arterial hypertension. Our objective was to prospectively examine the potential myocardial and functional determinants of exercise-induced rise of eNO in HF.Thirty-four consecutive ambulatory patients with chronic systolic HF (left ventricular ejection fraction [LVEF] ≤45%) underwent symptom-limited cardiopulmonary stress testing and echocardiography. eNO was determined immediately after exercise. Systemic endothelial dysfunction was assessed by asymmetric dimethylarginine (ADMA) and the L-arginine/ADMA ratio. In our study cohort (mean age 53 ± 13 years, 76% male, median LVEF 31%, interquartile range [IQR] 25%-40%), the mean eNO was 23 ± 9 ppb. eNO levels were higher in patients with diastolic dysfunction stages 2 or 3 than stage 1 or normal diastology (26.1 ± 9 vs 19.5 ± 7 ppb; P = .013). eNO had a positive correlation with estimated systolic pulmonary artery pressure (r = 0.57; P = .0009) and indexed left atrium volume (r = 0.43; P = .014), but it did not correlate with cardiopulmonary exercise test parameters, ADMA, or symptom score.In contrast to earlier reports, the increase in postexercise eNO observed in stable chronic systolic HF patients may be attributed to the presence of underlying pulmonary venous hypertension probably secondary to advanced diastolic dysfunction.

    View details for DOI 10.1016/j.cardfail.2012.08.356

    View details for Web of Science ID 000310179900008

    View details for PubMedID 23040116