Abstract 4234: Prognostic Implication of the Continuous Prognostic Spectrum of Coronary Flow Reserve in Patients with and without Angiographically Obstructive Coronary Artery Disease
Dual imaging of wall motion and coronary flow reserve (CFR) on left anterior descending (LAD) artery is now the state-of-the art technique for vasodilator stress echo. The additive prognostic value of CFR over regional wall motion has been established, but there is more than a binary (normal-abnormal ) response in CFR, which can be continuously titrated.
Objectives. To assess the prognostic value of Doppler echocardiographic derived CFR in patients with and without angiographically obstructive coronary artery disease (CAD). 1244 patients (785 men, age 64±11 yy) with known or suspected CAD underwent dipyridamole (up to 0.84 mg/kg over 6′) stress echo with CFR evaluation of left anterior descending artery by Doppler and coronary angiography. Patients were followed-up for a median of 17 months. Mean CFR in the entire population was 2.25±0.64. During follow-up, there were 227 events (26 deaths, 55 STEMI, and 146 NSTEMI). Patients (n=384) undergoing revascularization were censored. Using the Kaplan-Meier method, the lowest quartile of CFR (<1.80) was associated with a significantly (p<0.0001) worst event rate than other quartiles (Figure⇓), both considering the group with (83 vs 53%, p<0.0001) and without (53 vs 12%, p<0.0001) obstructive CAD at angiography. CFR is a strong and independent prognostic predictor in patients with known or suspected CAD, but the spectrum of prognostic stratification is expanded if the response is titrated according to a continuous scale rather than artificially dichotomized.