Reduction of Coronary Flow Velocity Reserve as the Main Driver of Prognostically Beneficial Coronary Revascularization

Background: Regional wall motion abnormality (RWMA) can be absent during stress echocardiography (SE) in patients with chronic coronary syndromes (CCS) and angiographically significant coronary artery disease (CAD) despite a reduction of coronary flow velocity reserve (CFVR). Objectives: To assess the value of a physiology-driven approach,based on CFVR, to coronary revascularization in patients with physiologically and anatomically significant disease of the left anterior descending (LAD) coronary artery. Methods: In a 3-center, observational study with retrospective analysis of prospectively acquired data, 749 patients with CCS, CFVR of the LAD <2.0, and ≥50% diameter stenosis of the LAD were enrolled. All patients were evaluated with dipyridamole (0.84 mg/kg in 6') SE. Patients were followed for 6.4±4.5 years for the outcome of all-cause death. Results: Inducible RWMA was present in 295 patients (39%). CFVR was lower in patients with inducible RWMA compared to those without (1.51±0.28 vs 1.65±0.25; p<00001). Coronary revascularization was performed in 514 (69%) patients (388 with percutaneous coronary intervention, 126 with coronary artery bypass surgery). Of them, 226 exhibited inducible RWMA and 288 isolated reduction of CFVR. During the follow-up, 185 (25%) deaths occurred. The 10-year survival in the entire study population was 70%. The survival at 10 years was markedly lower in conservatively treated patients compared to invasively treated patients (53 vs 76%; p<0.0001), with no significant difference between those with solitary reduction of CFVR and reduction of CFVR accompanied by concurrent inducible RWMA. Propensity Score weighted all-cause mortality risk resulted to be significantly higher for conservative than for invasive strategy (Propensity Score adjusted: HR 2.12, 95% CI 1.51-2.96; p<0.0001). Conclusions: In patients with CCS and physiologically and anatomically significant LAD disease, coronary revascularization driven by a reduction in CFVR is accompanied by a prognostic benefit independently of the presence of inducible RWMA.