Abstract 9277: Assessment of Coronary Flow Reserve for the Prediction of Long-Term Outcome in Patients with Non-Obstructive Coronary Artery Disease; Transthoracic Doppler Echocardiographic Study
Introduction. Coronary flow reserve (CFR) is dependent on microvascular blood flow which reflects the combined effects of the epicardial coronary stenosis and microvascular dysfunction. Various coronary risk factors cause impaired CFR, even in the absence of obstructive coronary artery narrowing. However, its prognostic importance for long-term outcome has not been fully discussed.
Methods. 272 patients (181 men, mean age 68 ± 12 years) with known or suspected coronary artery disease underwent transthoracic Doppler echocardiographic examination for the assessment of CFR in left anterior descending (LAD) artery. Angiolography revealed non-obstructive narrowing of LAD (<70%) in these patients. The cardiovascular events included cardiac death, myocardial infarction, unstable angina pectoris, and congestive heart failure.
Results. During a mean follow-up of 4.0 ± 1.9 years, cardiovascular events occurred in 32 patients, including cardiac death (n = 5), myocardial infarction (n = 6) and unstable angina (n = 9), congestive heart failure (n = 12). Multivariate analysis identified hemoglobin (p = 0.02), left ventricular mass index (p = 0.02), C-reactive protein (p = 0.01), and CFR (p <0.001) as significant and independent predictors of cardiovascular events. The ROC curve provided CFR <2.3 as the best cut-off value predicting late cardiovascular events (sensitivity was 0.82 and specificity was 0.69). No cardiovascular events occurred in patients with CFR ≥4.0.
Conclusions. We demonstrated that the measurement of CFR provided independent prognostic information in patients without obstructive narrowing of LAD. Close follow-up and strict control of coronary risk factors may be required in patients with CFR <2.3, even without obstructive narrowing of coronary arteries.
- © 2011 by American Heart Association, Inc.