Effect of Intravenous Dipyridamole on Coronary Flow Parameters in Patients with Isolated Coronary Artery Ectasia: Assessment by Transesophageal Echocardiography

Background: In a prospective study design, we sought to assess the effect of dipyridamole on coronary flow parameters in patients with isolated coronary artery ectasia (CAE) as compared to subjects with normal coronaries. Methods: We enrolled 30 patients with ectasia of the left anterior descending (LAD) artery (study group), and 10 subjects with normal coronaries (control group). All subjects underwent transesophageal echocardiography to record flow velocities in the proximal LAD coronary artery, and velocity time integrals were calculated. The diameter of the proximal LAD coronary artery was measured and flow was calculated. Dipyridamole (0.56 mg/kg) was administered intravenously and measurements were repeated 5 minutes later. Results: At baseline, systolic and diastolic velocities, systolic, diastolic, and total velocity time integrals were significantly higher in the control group (P < 0.05 for all), yet, systolic, diastolic, and total coronary flow were significantly higher in the study group (P < 0.05 for all). Following dipyridamole administration, systolic, diastolic, and total coronary flow were still significantly higher in the study group (P < 0.05 for all), yet, there was no significant difference between the two groups regarding the other parameters, and regarding coronary reserve values (P > 0.05 for all). Conclusions: We concluded that patients with isolated CAE have a higher resting coronary flow as compared to control subjects with normal coronaries. Intravenous dipyridamole administration in these patients maintained a significantly higher coronary flow, with a coronary flow reserve similar to controls. (Echocardiography 2011;28:350-357).