Noninvasive assessment of flow velocity and flow velocity reserve in the right gastroepiploic artery graft by transcutaneous Doppler echocardiography: comparison with an invasive technique.

Background: The measurement of flow velocity (FV) in coronary artery bypass grafts using a Doppler guidewire has provided useful clinical and physiologic information. The recently developed transcutaneous Doppler echocardiography is a noninvasive technique to measure FV and FV reserve (FVR) in the right gastroepiploic artery (GEA) graft. The purpose of this study was to evaluate whether transcutaneous Doppler echocardiography accurately measures FV and FVR in the right GEA graft in a clinical setting.

Methods: In 33 patients who underwent graft angiography for the assessment of the right GEA graft, FV in the right GEA graft was measured by transcutaneous Doppler echocardiography under the guidance of color flow Doppler imaging at the time of examination using a Doppler guidewire. FV in the midportion of the right GEA graft was measured at baseline and during hyperemic conditions using both transcutaneous Doppler echocardiography and a Doppler guidewire.

Results: There were excellent correlations between the value of FV obtained by transcutaneous Doppler echocardiography and those obtained with the Doppler guidewire (averaged peak velocity: y = 0.95 x + 1.46, r = 0.98, standard error of the estimate [SEE] = 2.94 cm/s; averaged systolic peak velocity: y = 0.94 x + 1.18, r = 0.97, SEE = 3.15 cm/s; diastolic peak velocity: y = 0.97 x + 1.62, r = 0.98, SEE = 4.40 cm/s; averaged diastolic peak velocity: y = 0.95 x + 1.75, r = 0.98, SEE = 3.60 cm/s). The FVR as determined by transcutaneous Doppler echocardiography showed a good correlation with that determined using the Doppler guidewire method (y = 0.90 x + 0.21, r = 0.92, SEE = 0.31).

Conclusions: Transcutaneous Doppler echocardiography proved to be an accurate noninvasive method to measure FV and FVR in the right GEA graft.