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Pelvic blood flow following aortobifemoral bypass with proximal end-to-side anastomosis
S E O'Connor1, D B Walsh, R M Zwolak
1Section of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03756.
Insights
End-to-side aortobifemoral bypasses often result in distal aortic occlusion, yet patients typically remain asymptomatic. Preoperative assumptions about blood flow requirements for preventing pelvic ischemia are frequently not met post-surgery.
Area of Science:
- Vascular Surgery
- Medical Imaging
- Hemodynamics
Background:
- End-to-side aortobifemoral bypass is a common surgical procedure.
- Pelvic ischemia is a potential complication following this surgery.
- Assumptions exist regarding the necessity of antegrade iliac flow to prevent ischemia.
Purpose of the Study:
- To investigate the source of pelvic blood flow after end-to-side aortobifemoral bypass.
- To assess distal aortic patency and iliac artery flow patterns in the first year post-surgery.
- To evaluate the validity of preoperative assumptions regarding pelvic perfusion.
Main Methods:
- Color duplex imaging was used to study nine patients.
- Patients were assessed in the first year after end-to-side aortobifemoral bypass.
- Preoperative arteriograms were analyzed for predictive factors.
Main Results:
- Six out of nine patients developed distal aortic occlusion within a mean of 4.4 months.
- Various patterns of retrograde or absent iliac blood flow were observed.
- No patient exhibited clinical signs of postoperative pelvic ischemia despite altered flow dynamics.
Conclusions:
- Distal aortic patency is not consistently maintained after end-to-side aortobifemoral bypass.
- Pelvic ischemia did not develop in patients with occluded distal aortas or altered flow.
- Preoperative assumptions about the necessity of antegrade flow for pelvic perfusion are often inaccurate.
Abstract:
Nine patients with end-to-side aortobifemoral bypasses were studied in the first year after surgery using color duplex imaging to determine the source of pelvic blood flow. No patient had clinical evidence of postoperative pelvic ischemia. Six of nine patients were found to have occluded distal aortas by duplex studies performed at a mean of 4.4 months postoperatively (range 0.8-8.2 months). Of those six patients, postoperative duplex examination demonstrated two with no common or external iliac blood flow, two with bilateral retrograde external iliac flow, and two with unilateral retrograde external iliac flow. Of the three patients with patent distal aortas, two had no demonstrable external iliac blood flow, while the third had continued antegrade flow through one external iliac and retrograde flow through the other. Analysis of preoperative arteriograms failed to reveal accurate predictors of postoperative distal aortic patency or retrograde iliac blood flow. Despite the preoperative assumption that prograde common iliac artery blood was required to prevent pelvic ischemia, distal aortic patency was maintained in only three of nine patients. In the six patients with prograde iliac blood flow, no ischemic symptoms were present, including two patients with complete absence of antegrade aortic or retrograde external iliac blood flow. Our observations indicate that assumptions which underlie the decision to perform end-to-side aortic anastomoses are often not borne out in the months following aortobifemoral bypass.