Pulsed Doppler velocity patterns produced by arterial anastomoses.

Centerstream velocity waveforms produced by end-to-end and end-to-side anastomoses constructed in the dog illeofemoral arterial system were studied with a 20 MHz pulsed Doppler velocimeter combined with spectral analysis. Flow disturbance was identified by changes in spectral width during the systolic phase of the cardiac cycle. Measurement of the maximum frequency and the spectral width at peak systole was used to quantify the magnitude of flow disturbance at varying locations proximal and distal to the anastomoses. Disruption of the normal laminar flow pattern observed in the unoperated dog artery was evident distal to both anastomotic configurations. An increase in spectral width reflecting disturbed flow was maximal during the deceleration phase of systole. Flow disturbance was localized to a zone within one diameter distal to the anastomosis and dissipated rapidly downstream. The velocity spectrum changes observed downstream of an anastomosis resemble the flow disturbances produced by low grade, nonpressure reducing arterial stenoses. This study suggests that spectral analysis of pulsed Doppler waveforms is a potentially useful method of anastomosis assessment both to rule out major flow disruption produced by technical error, and to provide insight into the role of turbulence in the development of anastomotic intimal hyperplasia.