Dyeless vascular surgery

Abstract

Purpose: The morbidity associated with contrast-based diagnostics performed for preoperative evaluation prior to vascular intervention ranges from 1 to 21%. These complications range from minor hematomas to death. However, these exams are commonly felt to be a necessary step to completely evaluate the arterial tree before intervention is undertaken. Since this has varied from our experience, we reviewed our experience with repair of abdominal aortic aneurysms (AAAs), carotid endartectomy (CEA), and lower extremity revascularization performed without preoperative contrast studies.

Materials and methods: During the last 10 years, we have performed 184 elective AAA repairs with abdominal-pelvis CAT scan without intravenous contrast as a preoperative study. During this same period of time, 903 CEAs were performed in 810 patients based solely on duplex ultrasonography or in combination with magnetic resonance angiography in cases where duplex ultrasonography was inconclusive (53 cases). Finally, over the last 30 months, we have performed 485 revascularizations in the lower extremity based solely on duplex ultrasonography mapping. Direct visualization of all major arteries from the distal aorta to the pedal vessels was performed using duplex imaging. Both the carotid duplex imaging and lower extremity duplex imaging were confirmed to have greater than 95 % positive predictive value during an initial phase of 50 cases confirmed with MRA and contrast angiography respectively.

Results: All cases of venous anomalies such as retrocaval left renal vein or left sided inferior vena cava in AAA patients were accurately identified and confirmed by intraoperative findings. No cases of horseshoe kidney were identified. Despite the presence of diminished femoral pulses in six patients, aortic reconstructions were performed with only duplex imaging. The 30 day mortality of AAA patients was 5% for elective repairs. In addition, no gross differences were appreciated with intraoperative findings of CEA as compared to preoperative duplex findings. However, in 5 cases CEA could not be performed due to extension of the lesion well above the available surgical exposure. The 30 day mortality of the CEA patients was 0.7% and the incidence of postoperative stroke or transient ischemic attack was 0.7%. Finally, in two early cases of lower extremity revascularization, the distal anastomosis was placed proximal to a lesion. This was appreciated during the procedure and corrected with a jump graft in each case.

Conclusions: These data suggest that AAA repair, CEA, and lower extremity revascularization can be performed without contrast based preoperative studies and without compromise to evaluation of disease, patient safety or patency of bypass grafts.

Introduction

The morbidity associated with contrast-based diagnostics performed for preoperative evaluation prior to vascular intervention including minor and major complications ranges from 1 to 21% especially in certain subpopulations [1], [2], [3], [4].These complications range from minor hematomas to death. However, these exams are commonly felt to be a necessary step to completely evaluate the arterial tree before intervention is undertaken even though the information obtained from these angiograms may be misleading. Information obtained from angiograms may be incomplete due to psuedo-occlusions as a consequence of air bubbles or extremely low flow. Underestimation of a stenotic area with standard contrast arteriography (CA) may be due to uniplanar views and the ribbon-effect. Poor visualization of patent vessels distal to occlusions especially with retrograde filling of distal patent vessels or problems with timing of the image may also result in errors. When evaluating an abdominal aortic aneurysm (AAA), the location of renal arteries on angiography or CAT scan with contrast may not be fully assessed due to an extremely tortuous aorta or when the AAA’s anterior aspect is extending superiorly after its origin.

Furthermore, other imaging modalities have advanced to supply much of the needed information for the intended procedures and may even add additional information not available by contrast based imaging modalities. This had led some centers to explore these alternative techniques for evaluation of the arterial tree. Therefore, to characterize the alternative techniques in the preoperative evaluation of the arterial tree prior to arterial procedures at our institution, we reviewed our experience with repair of abdominal aortic aneurysms, carotid endartectomy (CEA), and lower extremity revascularization performed without preoperative contrast studies.