Additional prognostic value of coronary flow reserve in diabetic and nondiabetic patients with negative dipyridamole stress echocardiography by wall motion criteria.

Objectives The aim of this prospective, multicenter, observational study was to compare the prognostic value of Doppler echocardiographic-derived coronary flow reserve (CFR) in diabetic and nondiabetic patients with known or suspected coronary artery disease and negative dipyridamole stress echocardiography. Background The prognostic value of CFR in diabetic patients with negative stress echocardiography remains unknown. Methods The study group consisted of 1,130 patients (207 diabetics) with known (n = 418) or suspected (n = 712) coronary artery disease and negative stress echocardiography by wall motion criteria. All underwent dipyridamole (up to 0.84 mg/kg over 6 min) echocardiography with CFR evaluation of left anterior descending artery by Doppler. A value of CFR <=2.0 was considered abnormal. Results Coronary flow reserve was abnormal in 309 (27%) patients. During a median follow-up of 16 months, 98 events (8 deaths, 24 ST-segment elevation myocardial infarctions, and 66 non-ST-segment elevation myocardial infarctions) occurred. In addition, 101 patients underwent revascularization and were censored. Multivariable prognostic indicators were abnormal CFR (p < 0.0001), anti-ischemic therapy at the time of testing (p = 0.002), age (p = 0.02), and resting wall motion abnormality (p = 0.05). The event rate was markedly higher (p < 0.0001) for both diabetic and nondiabetic patients with abnormal CFR as compared with diabetic and nondiabetic patients with normal CFR. Of note, a preserved CFR off therapy identified diabetic and nondiabetic patients with better survival and comparable yearly event rates (2.2% vs. 2.0%, p = 0.80). Conclusions Coronary flow reserve provides independent prognostic information in diabetic and nondiabetic patients with known or suspected coronary artery disease and negative dipyridamole stress echocardiography. In particular, a normal CFR off therapy is associated with better and similar survival in the 2 populations.