Long‐Term Prognostic Significance of Coronary Flow Velocity Reserve in Patients with Significant Coronary Artery Disease Not Involving the Left Anterior Descending Coronary Artery (Results from the SZEGED Study)

OBJECTIVE: Coronary flow velocity reserve (CFR) by pulsed Doppler echocardiography is a useful hemodynamic index to evaluate the coronary microcirculatory dysfunction in the left anterior descending coronary artery (LAD). The present study was designed to evaluate the long-term predictive value of CFR for mortality in patients with right (RC) and/or left circumflex coronary artery (CX) stenosis without epicardial LAD disease. METHODS: A total of 49 patients with significant RC and/or CX stenosis were enrolled in this prospective follow-up study. All patients had undergone coronary angiography demonstrating significant RC and/or CX stenosis without LAD disease and dipyridamole stress transoesophageal echocardiography as CFR measurement. RESULTS: The success rate of follow-up was 43 out of 49 (88%). During a mean follow-up of 97 +/- 29 months, 14 patients suffered cardiovascular deaths (12 sudden cardiac deaths and 2 strokes), and 1 patient died of pulmonal tumor. Patients who died during the follow-up had significantly lower CFR values (1.85 +/- 0.43 vs. 2.31 +/- 0.57, P < 0.05). Using ROC analysis, CFR <2.09 had the highest accuracy in predicting cardiovascular survival (sensitivity 80%, specificity 57%, area under the curve 73%, P = 0.003). The logistic regression model identified only CFR as an independent predictor of survival (hazard ratio [HR] 6.26, 95% CI of HR 1.23-19.61, P = 0.024). CONCLUSIONS: Long-term prognostic significance of CFR for the prediction of mortality has been demonstrated during a 9-year follow-up in patients with significant coronary artery disease not involving the LAD.