Poster Session: Aortic Stenosis

Background: Patients with left main coronary artery (LMCA) stenosis are considered to be vulnerable population that requires reliable assessment of functional significance of lesions observed on coronary angiography.The aim of this study was to determine the prognostic value of noninvasively measured coronary flow reserve (CFR) in patients with angiographically assessed intermediate LMCA stenosis during long-term follow up.Methods: Ninety eight patients, 60.2+9.1 years of age, 83 (84.7%) patients male, having LMCA stenosis assessed by coronary angiography to be ≤50% (diameter stenosis) and without significant left anterior descending artery (LAD) stenosis, were enrolled in this prospective study.Single vessel disease was present in 45 (45.9%) patients.Transthoracic Doppler echocardiography was used to obtain CFR values.All measurements were performed for the medial segment of LAD in baseline conditions, and after the hyperemic stimuli that was induced with adenosine (at infusion rate 140 mcg/kg/min).CFR values were calculated as the ratio between hyperemic maximal flow velocity and resting (baseline) flow velocity.Participants, who were referred to coronary artery by-pass based on CFR ≤ 2, were excluded from further analysis.Patients were followed for the mean period of 14.7 +9.9 months for the occurrence of composite end point including cardiovascular death, myocardial infarction, hospitalization due to unstable angina and clinically guided revascularization.Results: Mean CFR value was 2.3+0.5.Twenty eight patients had CFR ≤2 (28.6%), while 70 patients had CFR .2(71.4%).Mean CFR value of 1.9+0.5 for patients having events was significantly lower, compared to those who were free of events where mean CFR value was 2.4+0.5 (p=0.027).Patients with lower CFR values (CFR≤2) had a statistically significant higher event rate (7 pts, 25%) compared to those whit CFR . 2 (5 pts, 7%), (p,0.05) during follow-up.By Kaplan-Meier analysis and log rank test, it was shown that patients having CFR.2 had a significantly higher survival rate (P ,0.001).Value of the coronary flow reserve (CFR) ≤2 was associated with a significant risk increase of experiencing events of the composite end point (P=0.017).Conclusion: CFR measured by transthoracic Doppler echocardiography provides reliable and precise, yet non-invasive tool for the assessment of functional severity of LMCA disease that carries significant prognostic information in long-term follow-up.