Using transthoracic Doppler echocardiography to diagnose reduced coronary flow velocity reserve in the posterior descending coronary artery in children with elevated right ventricular pressure

Abstract

Background: Advances in transthoracic Doppler echocardiography enable noninvasive measurements of coronary flow velocity and coronary flow velocity reserve (CFVR) in the posterior descending coronary artery (PD). Methods and Results: To evaluate CFVR in the PD of children with elevated right ventricular (RV) pressure, 19 children with RV pressure overload and 13 age-matched controls with normal RV pressure were studied using transthoracic Doppler echocardiography. Average peak flow velocity (APV) was measured at rest and in hyperemic conditions (intravenous administration of adenosine of 0.16 mg·kg-1·min-1). Compared with controls, the PD CFVR was significantly reduced in the patients with elevated RV pressure (1.87±0.42 vs 2.49±0.55, p<0.01) because their mean baseline APV was significantly greater (27±6 vs 19±4cm/s, p<0.01), although hyperemic APV was not significantly different (49±10 vs 48±14 cm/s, p=NS). Conclusions: PD CFVR is limited in patients with elevated RV pressure because of elevation of the baseline resting flow velocity.