CONGRESS ABSTRACT

Background. A low coronary diastolic-systolic flow velocity ratio in resting condition (DSVR) is associated with functionally significant coronary artery disease (CAD), but whether it is associated with cardiovascular outcome is not known. While commonly perceived as an exclusively invasive measurement, DSVR is in fact also incidentally measured during stress echocardiography (SE), when coronary flow velocity reserve (CFVR) Doppler measurement in the left anterior descending coronary artery is performed.   Objectives. We assessed whether DSVR on rest echocardiography is associated with cardiovascular outcome and all-cause mortality.   Methods. We recruited 1433 patients with suspected CAD (median age 68 years, 38% females), referred to two centers for SE. Clinical, rest echocardiography variables, including DSVR, and SE parameters were recorded. Cardiovascular death or non-fatal myocardial infarction was the primary composite endpoint; all-cause mortality was the secondary endpoint. Propensity-score matching was also used to reduce the bias from confounding variables.   Results. The positivity rate of reduced DSVR (≤1.5) was 32%. During a mean follow-up of 4.9 years, 93 unique primary endpoints (6.5%) were recorded: 49 nonfatal myocardial infarctions (3.4%) and 50 cardiovascular deaths (3.5%). Among risk factors and rest echocardiography variables, age, diabetes mellitus, known CAD, left ventricle ejection fraction, rest diastolic velocity and DSVR were associated with the primary endpoint and also with all-cause mortality at multivariable analysis. A reduced DSVR ratio more than doubled the risk of cardiovascular events, also after correction with propensity score matching. DSVR remained associated also after stress variables (CFVR and reversible ischemia) were added to the rest model.   Conclusions. Reduced DSVR, a measurement performed on rest echocardiography, is independently and strongly associated with cardiovascular outcome and all-cause mortality and maintains the association in all subgroups of clinical interest, such as diabetics or patients with normal CFVR at SE. DSVR and CFVR appear to be independent and synergistic in their association with the primary cardiovascular endpoint and all-cause mortality.