Noninvasive assessment of coronary flow velocity and coronary flow velocity reserve in the right coronary artery by transthoracic Doppler echocardiography: comparison with intracoronary Doppler guidewire.

The aim of this study was to evaluate whether coronary flow velocity (CFV) and coronary flow velocity reserve (CFVR) in the posterior descending right coronary artery can be reliably measured by transthoracic Doppler echocardiography (TTDE). In 17 patients, CFV in the posterior descending right coronary artery was measured with TTDE at the time of Doppler guidewire examination. CFV was measured by both methods at baseline and under hyperemic conditions. TTDE data were obtained for 12 patients. CFV and CFVR by TTDE show a good correlation with those obtained by the Doppler guidewire method (average diastolic peak velocity: r = 0.98, y = 0.85x + 5.26; diastolic peak velocity: r = 0.97, y = 0.94x + 3.39; CFVR: r = 0.97, y = 0.87x + 0.56). CFV and CFVR in the posterior descending right coronary artery obtained noninvasively by TTDE accurately reflect these values obtained by the invasive Doppler guidewire method.