Coronary Flow Velocity Reserve in Patients with Ascending Aorta Aneurysm

Abstract

Ascending aorta aneurysms (AAA) are one of the leading causes of morbidity and mortality. Impairment in coronary flow may contribute to cardiovascular consequences in AAA patients. Coronary flow velocity reserve (CFVR) has been considered an important diagnostic index of the functional capacity of coronary arteries noninvasively. The aim of this study was to evaluate, by noninvasive CVFR, whether patients with AAA demonstrate significant coronary microvascular dysfunction in the absence of coronary artery disease (CAD). We prospectively included 44 patients with thoracic AAA in the absence of concomitant CAD (30 men, 14 women; mean age 57.5±8.4years). A total of 36 patients without aortic dilatation (mean age 55.2±9.9years) were selected as the control group. Coronary flow velocities in the distal left anterior descending (LAD) artery were measured using transthoracic echocardiography. CFVR was calculated as the hyperemic to resting coronary diastolic peak velocities ratio. Compared with controls, patients with AAA had higher baseline LAD peak diastolic coronary flow velocities (28.3±5.8 vs. 25.2±4.5cm/sec, P=0.01), lower hyperemic LAD flow velocities (54.0±10.3 vs. 57.2±12.7cm/sec, P=0.220), and consequently lower CFVR (1.9±0.3 vs. 2.3±0.5, P<0.001). Multivariate linear regression analysis showed that CFVR was independently associated only with aortic systolic diameter (AoSD) (β=-0.679, P=<0.001). Our study demonstrates that noninvasive CFVR is significantly reduced in patients with AAA and AoSD is the most important determinant of impaired CFVR.