Age- and Gender-Specific Prognostic Cutoff Values of Coronary Flow Velocity Reserve in Vasodilator Stress Echocardiography

Abstract

Coronary flow velocity reserve (CFVR) of the left anterior descending artery is useful for risk stratification during stress echocardiography (SE) as an add-on to regional wall motion abnormalities (RWMA). We sought to provide sex- and age-specific prognostic cutoff values for CFVR. A total of 5,577 patients (2,284 women; 110 age≥85years) who underwent dipyridamole SE with evaluation of RWMA and CFVR were enrolled in a multicenter prospective SE registry. Death and myocardial infarction were the clinical end points. During 20months' median follow-up, 649 events (236 deaths, 413 infarctions) occurred: 288 in women and 38 in patients ≥85years. At receiver operating characteristics analysis, the best prognostic cutoff value for CFVR was similar for men (2.03) and women (2.02) and consistent across all age strata (<45years: 2.03; 45-54years: 2.04; 45-64years: 2.03; 65-74 and 75-84years: 2.0) except for patients >85years, who showed 1.90 as the optimal value. Independent predictors of mortality or myocardial infarction were RWMA (hazard ratio [HR]=5.42), reduced CFVR (HR=3.26), resting ejection fraction (HR=0.98), smoking habit (HR=1.41), age (HR=1.02), and prior percutaneous coronary intervention (HR=1.20) in patients age <85years; and RWMA (HR=5.42), smoking habit (HR=3.24), and resting ejection fraction (HR=0.97) in those age ≥85years. CFVR added a prognostic contribution over clinical parameters, resting ejection fraction, and stress-induced RWMA in all age and sex groups except men >85years. A sex-independent value of CFVR ≤2.0 provides the optimal prognostication across all age groups, except for those ≥85years in whom a cutoff ≤1.90 is needed. Risk stratification is more effective for all age groups when CFVR is combined with RWMA.