The additional prognostic power of diabetes mellitus on coronary flow reserve in patients with suspected coronary artery disease.

Aims: The aim of the present study was to assess the relative prognostic value of coronary flow reserve (CFR) and diabetes mellitus (DM) in patients with suspected coronary artery disease (CAD).

Methods: We prospectively studied 347 inhospital patients with chest pain. Coronary angiography was performed in 281 patients (81%). All patients underwent a transthoracic echocardiographic study to evaluate left ventricular function and a stress vasodilator transoesophageal echocardiographic study to evaluate simultaneously CFR and the degree of aortic atherosclerosis (AA). The primary outcome of the study was cardiovascular mortality.

Results: During a mean follow-up of 41+/-12 months, 22 patients suffered cardiovascular death. Diabetic patients had a significantly higher AA grade and tended to have a lower CFR and more often significant CAD. Patients with normal CFR had less often significant CAD and tended to have less often DM. Significant univariable predictors of cardiovascular survival were DM, LV end-diastolic diameter, CFR and AA grade. Multivariable regression analysis showed that only CFR (hazard ratio (HR) 2.9, P=0.01) and diabetes (HR 3.1, P=0.01) were independent predictors of cardiovascular survival.

Conclusions: CFR and DM evaluations offer complementary information during vasodilator stress TEE testing. Patients with reduced CFR (impaired microcirculatory function) and DM have the worst prognosis.