Abstract 17976: Functional Correlates and Prognostic Value of Coronary Flow Velocity Reserve by Vasodilator Stress Echocardiography in Hypertrophic Cardiomyopathy
Background: A reduction in coronary flow velocity reserve (CFVR) n is a major mechanism for ischemia in hypertrophic cardiomyopathy (HCM).
Hypothesis: To assess the functional correlates and prognostic value of CFVR during vasodilator stress echocardiography (SE)
Methods: We enrolled 113HCM patients (age 53±15 years, 62 male) studied with dipyridamole (n=68) or adenosine (n=45) SE and CFVR assessment using pulsed wave Doppler sampling on left anterior descending coronary artery. We defined SE positivity as reduction of CFVR (<2.0). All patients completed the clinical follow-up.
Results: Positive SE for reduction in CFVR occurred in 41/113 patients (36%). During a median follow-up of 27 months, 34 events occurred: 3 deaths, 14 acute heart failure, 2 sustained ventricular tachycardias and 15 atrial fibrillations. Events occurred in 26/41 patients with abnormal and in 8/72 of those with normal CFVR (63 vs 11% p<.0001), with a relative risk of 5.71 (CI: 2.85-11.4). The prognostic separation was striking with CFVR-based criterion (X2: 32.018, p<0.0001). When sequential chi-square models for the prediction of events were used, SE CFVR-related criteria showed significant incremental prognostic value over clinical and resting echocardiography parameters (+53%, Figure, left panel). When the CFVR response was titrated as a continuous rather than binary variable, patients in the lowest tertile showed the worse prognosis (Figure, right panel).
Conclusions: In HCM patients, vasodilator SE positivity with reduction in CFVR occurs in about 1 out of 3 patients, is unrelated to resting left ventricular outflow tract gradient or maximal wall thickness, and is associated to a clearly worse outcome. The prognostic value of reduced CFVR is additive over standard clinical and echocardiographic predictors. The spectrum of prognostic stratification is expanded if the response is titrated according to a continuous scale rather than artificially dichotomized.
Author Disclosures: Q. Ciampi: None. L. Cortigiani: None. M. Tesic: None. B. Beleslin: None. F. Rigo: None. A. Djorkievic-Dikic: None. E. Picano: None.
- © 2016 by American Heart Association, Inc.