ABSTRACT
INTRODUCTION: Angina, myocardial ischemia, and coronary artery physiology in hypertrophic cardiomyopathy (HCM) are poorly understood. However, coronary computed tomography angiography (CCTA) with fractional flow reserve from CT (FFRCT) analysis offers a non-invasive method for evaluation of coronary artery volume to myocardial mass ratio (V/M) that may provide insight into such mechanisms. Thus, we sought to investigate changes in V/M in HCM. METHODS: A retrospective analysis was performed on 37 HCM patients and 37 controls matched for age, sex, and cardiovascular risk factors; CCTA-derived coronary artery lumen volume (V) and myocardial mass (M) were used to determine V/M. FFRCT values were calculated for the left anterior descending (LAD), left circumflex (LCx) and right coronary (RCA) arteries as well as the 3-vessel cumulative FFRCT values. RESULTS: HCM patients had significantly increased myocardial mass (176⯱â¯84 vs. 119⯱â¯27â¯g, pâ¯<â¯0.0001) and total coronary artery luminal volume (4112⯱â¯1139 vs. 3290⯱â¯924â¯mm3, pâ¯<â¯0.0001) that resulted from increases in segmented luminal volumes of both the left and right coronary artery systems. However, HCM patients had significantly decreased V/M (23.8⯱â¯5.9 vs. 26.5⯱â¯5.3â¯mm3/g; pâ¯=â¯0.026) which was further decreased when restricting V/M analysis to those HCM patients with septal hypertrophy (22.4â¯mm3/g, pâ¯=â¯0.01) that was mild-moderately predictive of HCM (AUCâ¯=â¯0.68). HCM patients also showed significantly lower nadir FFRCT values in the LCx (0.87⯱â¯0.06 vs. 0.91⯱â¯0.06, pâ¯=â¯0.02), and cumulative 3-vessel FFRCT values (2.58⯱â¯0.18 vs. 2.63⯱â¯0.14, pâ¯=â¯0.006). CONCLUSIONS: HCM patients demonstrate significantly greater coronary volume. Despite this, HCM patients suffer from decreased V/M. Further prospective studies evaluating the relationship between V/M, angina, and heart failure in HCM are needed.