CALCULATION OF AORTIC REGURGITANT VOLUME BY A NEW DIGITAL DOPPLER COLOR-FLOW MAPPING METHOD - AN ANIMAL STUDY WITH QUANTIFIED CHRONIC AORTIC REGURGITATION

Objectives. The aim of the present study was to quantitate aortic regu rgitant volume and regurgitant fraction in a chronic animal model with surgically created aortic regurgitation using a new semiautomated col or Doppler flow calculation method. Background. The conventional nonin vasive methods for evaluating the severity of aortic regurgitation hav e not been accepted widely nor compared with truly quantitative refere nce standards, Methods. Eight to 20 weeks after aortic regurgitation w as surgically induced in six sheep, a total of 22 hemodynamic states w ere studied, Electromagnetic how probes and meters provided reference flow data, Epicardial color Doppler echocardiographic studies were pet -formed to image left ventricular outflow tract forward and aortic reg urgitant blood flows, The new method digitally integrated spatial and temporal color flow velocity data for left ventricular outflow tract f orward flow and ascending aortic regurgitant flow, The pulsed Doppler method using the velocity-time integral was also used to obtain regurg itant volumes and regurgitant fractions. Results. Regurgitant volumes and regurgitant fractions by the new method agreed well with those obt ained electromagnetically, whereas the pulsed Doppler method overestim ated these reference data (mean [+/- SD] difference 0.23 +/- 2.9 ml vs , 11 +/- 5.8 ml, p < 0.0001 for regurgitant volume; mean difference 1. 2 +/- 7.6% vs. 19 +/- 13%, p < 0.0001 for regurgitant fraction). Concl usions. This animal study, using strictly quantified aortic regurgitan t volumes, demonstrated that the digital color Doppler method provides accurate aortic regurgitant volumes and regurgitant fractions without cumbersome measurements. (C) 1997 by the American College of Cardiolo gy.