Clinical outcome in patients with intermediate stenosis of left anterior descending coronary artery after deferral of revascularization on the basis of noninvasive coronary flow reserve measurement.

Background: Several reports suggest that noninvasive measurements of coronary flow reserve (CFR) by use of echocardiography may support decision making in intermediate stenosis of the left anterior descending coronary artery (LAD). The aim of the present study was therefore to analyze the clinical outcome in patients with intermediate stenosis of LAD after deferral of coronary revascularization on the basis of noninvasive CFR measurement.

Methods: the study population included 280 patients with intermediate LAD stenosis (50-70% by angiography) (62.2 +/- 9.6 years). All the patients underwent transthoracic CFR assessment of LAD (after dipyridamole infusion) within 2 weeks from coronary angiography. If CFR of LAD was < or = 2, PTCA was recommended; if CFR was > 2, medical treatment was chosen. Primary end points were cardiac death, myocardial infarction, coronary revascularization procedure, and unstable angina.

Results: mean follow-up was 43 +/- 11 months (range 12-52 months). In 150 patients (53.6%) (CFR < or = 2), coronary artery revascularization was performed (PTCA group); the remaining 130 patients (46.4%) (CFR > 2) were medically treated (medical group). Survival from cardiac death was 94% in the PTCA group and 92.4% in the medical group (P = 0.56). As for all cardiac events, the Kaplan-Meier percentage survival from cardiac events was 88.3% in the PTCA group and 86.4% in the medical group (P = 0.36).

Conclusions: even if CFR as a "stand-alone" diagnostic criterion suffers from several structural limitations, a combined strategy including also other clinical and instrumental measurements before undergoing interventional procedures could improve the cost-benefit practice, in particular, for the management of patients with intermediate LAD stenosis.