Aims: The aim of the study was to evaluate the prognostic value of Doppler echocardiographic-derived coronary flow reserve (CFR) over regional wall motion in patients with known or suspected coronary artery disease (CAD) undergoing dipyridamole echocardiography test (DET).
Methods and results: In a prospective, multicentre, observational study, we evaluated 1145 patients (702 males; 64 +/- 11 years) who underwent high-dose dipyridamole (0.84 mg/kg over 6 min) stress echo with CFR evaluation of LAD by Doppler. DET was positive for regional wall motion abnormalities in 291 (25%) and negative in 854 (74%) patients. Mean CFR was 2.2 +/- 0.5. At individual patient analysis 702 patients had normal (CFR > 2.0) and 443 had abnormal CFR on LAD. During a median follow-up of 27 months, 109 events occurred: 16 deaths, 17 non-fatal myocardial infarctions, 76 re-hospitalizations for unstable angina. The 30 months infarction-free survival showed the best outcome for those patients with negative DET by wall motion criteria and normal CFR and the worst outcome for patients with positive DET by wall motion and abnormal CFR (99 vs. 68%, P < 0.001). At multivariable analysis, CFR on LAD [hazard ratio (HR) 2.4, 95% CI 1.1-5.4, P = 0.030], medical therapy at time of testing (HR 2.8, 95% CI 1.2-6.6, P = 0.022), DET positivity for regional wall motion abnormalities (HR 3.6, 95% CI 1.5-8.7, P = 0.000), and angina on effort (HR 6.3, 95% CI 2.7-14.8, P = 0.000) were independent prognostic predictors of hard cardiac events.
Conclusion: In patients with known or suspected CAD, DET result by wall motion criteria and CFR are additive and complementary for the identification of patients at risk of experiencing hard events.