Objectives: The purpose of this study was to investigate coronary blood flow properties in patients with diffuse coronary artery ectasia (CAE) associated with exercise-induced myocardial ischemia.
Methods: Seventeen patients with diffuse CAE and without coexisting coronary artery stenosis were enrolled in the study (CAE group). CAE was defined as luminal dilatation 1.5 to 2 times that of the adjacent normal coronary artery segment or the diameter of the corresponding coronary artery of the control group when there was no normal segment. The age- and sex-matched control group (n = 20) comprised patients with normal epicardial coronary arteries. Coronary blood flow velocities were obtained invasively by use of Doppler scanning flow wire. Coronary flow reserve (CFR) was measured by administration of intracoronary papaverine as the hyperemic stimulus. Volumetric coronary blood flow was estimated by multiplying the velocity time integral of coronary blood flow with the cross-sectional area of the coronary artery and the heart rate.
Results: Fifteen patients with CAE, but none of the patients in the control group, had electrocardiographic signs of myocardial ischemia at peak exercise on ergometry. Baseline average peak velocities (APVs) of coronary blood flow were similar in the 2 groups. Peak hyperemic APVs of coronary blood flow were lower in the CAE group than in the control group (17.5 +/- 7.4 cm/s vs 41.5 +/- 12.6 cm/s, respectively, P <.001). Volumetric coronary blood flow was significantly higher in the CAE group than in the control group, both at rest and at hyperemia (146.3 +/- 71.2 cm3/min vs 45.1 +/- 16.1 cm3/min, respectively, P <.001, and 202 +/- 87.3 cm3/min vs 104.1 +/- 37.6 cm3/min, respectively, P <.003). The mean CFR of the CAE group was significantly reduced compared with that of the control group (1.51 +/- 0.31 vs 2.67 +/- 0.52, respectively, P <.001).
Conclusions: The CFR is significantly reduced in patients with diffuse CAE compared to a matched control group. Although volumetric coronary blood flow is significantly higher in CAE, microcirculatory dysfunction that is reflected as depressed CFR may be the underlying cause of exercise-induced myocardial ischemia.