[Blood flow dynamics and dimensions of the descending thoracic aorta in patients with intra-aortic swirling echoes: assessment by biplane transesophageal echocardiography].

To examine the blood flow dynamics in the descending thoracic aorta (DAo) where intra-aortic swirling echo contrast was observed, we analyzed the flow velocity patterns (FVP) in DAo and the DAo dimensions by biplane transesophageal echocardiography (TEE) in 9 patients with intraortic swirling echo contrast and in 25 control subjects (N). We recorded sampling volumes with pulsed Doppler echocardiograms at 3 sites: median, central, and lateral sites on longitudinal scan images and on the DAo at the level of the mitral valve. We measured systolic peak flow velocity (Vp), time from the onset of the systolic flow to Vp (acceleration time: AT), deceleration time (DT) of the systolic flow, and AT/(AT + DT) for each sampling volume in the DAo. From the M-mode echogram of DAo, we measured the maximum dimension of the aorta, which usually coincided with the mid to late systolic phase. In the normal controls, the systolic forward flow was followed by a small reversal flow in early diastole and then by a small forward flow during holodiastole. Vp was highest at the center (64 +/- 10 cm/sec), then at the median (60 +/- 11 cm/sec) and lowest in the lateral (56 +/- 9 cm/sec; p < 0.01 vs center) sites in the DAo. AT was 70 +/- 13 msec and DT 215 +/- 26 msec. This flow velocity profile in the DAo was observed in both the control and patient groups. In patients with intra-aortic swirling echoes, Vp was markedly low (33 +/- 7 cm/sec; p < 0.001 vs N) and dimension of the DAo (13 +/- 2 mm/m2 in N) was significantly enlarged (21 +/- 7 mm/m2; p < 0.001 vs N), which might be related to swirling echoes and mural thrombi at the lateral portion in the DAo. Thus, we concluded that intra-aortic swirling echoes closely related to the production of mural thrombi observed mainly at the lateral site of the significantly dilated DAo.