- Pediatric Pulmonology
Clinical Assistant Professor, Pediatrics - Pulmonary Medicine
Fellowship: Stanford University Pulmonary and Critical Care Fellowship (2023) CA
Board Certification: American Board of Pediatrics, Pediatrics (2020)
Residency: Stanford University Pediatric Residency at Lucile Packard Children's Hospital (2020) CA
Medical Education: Stanford University School of Medicine (2017) CA
Clinical use of shear-wave elastography for detecting liver fibrosis in children and adolescents with cystic fibrosis.
Complications from liver cirrhosis are a leading cause of death in children with cystic fibrosis. Identifying children at risk for developing liver cirrhosis and halting its progression are critical to reducing liver-associated mortality.Quantitative US imaging, such as shear-wave elastography (SWE), might improve the detection of liver fibrosis in children with cystic fibrosis (CF) over gray-scale US alone. We incorporated SWE in our pediatric CF liver disease screening program and evaluated its performance using magnetic resonance (MR) elastography.Ninety-four children and adolescents with CF underwent 178 SWE exams, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT) and platelet measurements. Of these, 27 children underwent 34 MR elastography exams. We evaluated SWE performance using 6-MHz and 9-MHZ point SWE, and 9-MHz two-dimensional (2-D) SWE.The 6-MHz point SWE was the only method that correlated with MR elastography (r=0.52; 95% confidence interval [CI] 0.20-0.74; P=0.003). SWE of 1.45 m/s distinguished normal from abnormal MR elastography (79% sensitivity, 100% specificity, 100% positive predictive value [PPV], 55% negative predictive value [NPV], area under the receiver operating characteristic [AUROC] curve 0.94). SWE of 1.84 m/s separated mild-moderate (3.00-4.77 kPa) from severe (>4.77 kPa) MR elastography (88% sensitivity, 86% specificity, 78% PPV, 93% NPV, AUROC 0.79). Elevations of AST, ALT, GGT and thrombocytopenia were associated with higher SWE. AST-to-platelet ratio index of 0.42, fibrosis-4 of 0.29, and GGT-to-platelet ratio of 1.43 all had >95% NPV for SWE >1.84 m/s.Given its correlation with MR elastography, SWE might be a clinically useful predictor of liver fibrosis. We identified imaging criteria delineating the use of SWE to identify increased liver stiffness in children with CF. With multicenter validation, these data might be used to improve the detection and monitoring of liver fibrosis in children with CF.
View details for DOI 10.1007/s00247-021-05015-w
View details for PubMedID 33759025
New Algorithm for the Integration of Ultrasound Into Cystic Fibrosis Liver Disease Screening.
Journal of pediatric gastroenterology and nutrition
2019; 69 (4): 404–10
Liver nodularity occurs across the spectrum of cystic fibrosis liver disease (CFLD), from regenerative nodules to cirrhosis, and can occur without liver enzyme abnormalities. Our aims were to determine if incorporating abdominal ultrasound (US) with annual laboratory testing improves the detection of CFLD and establish CF-specific thresholds for liver screening labs.CF patients at least 6 years old who were exocrine pancreatic-insufficient had an US with Doppler and shear wave elastography. Patients were divided into Normal, Echogenic, or Nodular groups, based on US findings. Results were compared with aspartate aminotransferase (AST), alanine aminotransferase (ALT), platelets, AST to platelet ratio index (APRI), Fibrosis 4 (FIB-4), and gamma-glutamyl transferase (GGT) to platelet ratio (GPR). Receiver operator curve, sensitivity, specificity, positive predictive value, negative predictive value, and optimal cut-off with Youden Index were calculated.From 82 patients, incorporation of US identified more nodular livers than using labs alone. The Nodular group had significantly greater median AST (44), ALT (48), GGT (46), APRI (0.619), FIB-4 (0.286), GPR (1.431). Optimal cut-offs to detect liver nodularity in CF were AST >33, ALT >45, GGT >21, Platelets <230, APRI >0.367, FIB-4 >0.222, GPR >0.682. Using GGT, APRI, and GPR, we generated an algorithm to direct the use of US in CFLD screening.Using modified serum lab thresholds, addition of liver fibrosis indices, and/or abdominal US can increase detection of liver nodularity in CF. A combination of GGT, GPR, and APRI can help direct which CF children should undergo US evaluation. These tools may improve earlier identification of fibrosis and/or cirrhosis in CF patients.
View details for DOI 10.1097/MPG.0000000000002412
View details for PubMedID 31181020
- beta 1-Subunit of the calcium-sensitive potassium channel modulates the pulmonary vascular smooth muscle cell response to hypoxia AMERICAN JOURNAL OF PHYSIOLOGY-LUNG CELLULAR AND MOLECULAR PHYSIOLOGY 2018; 315 (2): L265–L275
Disrupted BKCa Channel beta 1 Subunit Gene Contributes to Vascular Dysfunction in Pulmonary Hypertension
FEDERATION AMER SOC EXP BIOL. 2017
View details for Web of Science ID 000405461402450
Anti-MDA5-Positive Dermatomyositis Presenting as Fever of Unknown Origin
JOURNAL OF GENERAL INTERNAL MEDICINE
2016; 31 (12): 1530-1536
Dermatomyositis is a chronic systemic autoimmune disease characterized by inflammatory infiltrates in the skin and muscle. The wide variability in clinical and serologic presentation poses a diagnostic challenge for the internist. Appreciation of the clinical variants of dermatomyositis allows for expedient diagnosis and avoidance of diagnostic error. We illustrate these challenges with the case of a 51-year-old Vietnamese-American man who initially presented with fever of unknown origin in the absence of overt skin and muscle manifestations. The diagnosis of dermatomyositis was not evident on several clinical encounters due to the absence of these hallmark symptoms. We review the variable clinical manifestations of a subtype of dermatomyositis associated with an autoantibody against melanoma differentiation-associated protein 5 (anti-MDA5) and suggest consideration of dermatomyositis as a diagnosis in patients presenting with systemic illness and markedly elevated ferritin, even in the absence of elevated muscle enzymes and classic autoantibodies.
View details for DOI 10.1007/s11606-016-3769-0
View details for Web of Science ID 000389626600028
View details for PubMedID 27350281
View details for PubMedCentralID PMC5130943
KCNMB1(-/-) Mice as a Model of Pulmonary Arterial Hypertension
FEDERATION AMER SOC EXP BIOL. 2016
View details for Web of Science ID 000406444001556
- Pulmonary artery smooth muscle cell endothelin-1 expression modulates the pulmonary vascular response to chronic hypoxia AMERICAN JOURNAL OF PHYSIOLOGY-LUNG CELLULAR AND MOLECULAR PHYSIOLOGY 2015; 308 (4): L368-L377