Acute Infrarenal Aortic Thrombosis During Aortoiliac ...

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A 61-year-old diabetic woman was admitted to the. Peter Bent Brigham Hospital because of claudication in her right calf. Two years previously, she had under-.
Acute Infrarenal Aortic Thrombosis During Aortoiliac Reconstruction Douglas P. Grey, M.D.* Richard Shemin, M.D. Nathan Couch, M.D.

A ORTOILIAC occlusive disease is a common enthat is slowly progressive, permitting the development of collateral circulation. In contrast, acute infrarenal aortic thrombosis is a rare catastrophic event in the total spectrum of vascular problems. The process precludes adequate collateral compensation, leads to severe lower extremity ischemia, and requires prompt surgical intervention.1-4 Case Reports

IAJL tity

Tzwio patietnts developed acuite infrar-enal aortic thl-ontibosis wh ile under-goinlg ao-toiliac reconstr-uctioni. Thlis conditioni was suspected when ther-e was a sluddetn loss of aortic piulsationis that were previolusly pr-esent. On1ce di'agniosed, a pr omlpt and a,gg-essize sultgical approach was necessary, as described in this report.

Case 1 A 61-year-old diabetic woman was admitted to the Peter Bent Brigham Hospital because of claudication in her right calf. Two years previously, she had undergone bilateral femoral popliteal saphenous vein bypass grafts for severe bilateral claudication. Eighteen months postoperatively, claudication recurred in her left leg. At the time of admission, she had a blood pressure of 2 10/100, absent femoral and distal pulses in her right leg, and weakly present pulses in her left leg. Angiography disclosed severe mid-aortic stenosis, patent internal iliac arteries, high-grade stenosis at the origin of the right external iliac artery, and patency of both femoral popliteal vein grafts. Intraoperatively, after dissection of the infrarenal aorta, there was sudden loss of common iliac and distal aortic pulses. The patient was given 6,000 units of heparin intravenously, and the blood pressure From the Department of Surgery, Peter BenttBrigham Hospital, Boston, Massach usetts.

*Presently a resident in Thoracic Surgery, Texas Heart Instituite, Houiston, Texas. Address for- reprints: Doluglas P. Grey, Division of Cardiovascular Suirgery, P.O. Box 20345, Houistoni,

Texas

77225.

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dropped from 180/90 to 80/50 shortly thereafter. The external iliac arteries were mobilized. The proximal anastomosis of the aorto-bi-iliac bypass graft was performed. Fogarty catheter thrombectomies were then performed through the external iliac arteriotomies. On the right, fresh clot was evacuated from the femoral system. On the left, newly formed thrombus was retrieved on both proximal and distal catheterizations. The distal anastomoses were completed and femoral pulses were present bilaterally after flow was again reestablished. Because popliteal peripheral pulses were not present, bilateral common femoral arteriotomies and thrombectomy of the superficial and profunda femoral arteries along with saphenous vein grafts were performed. Fresh clots were retrieved from all vessels. The right dorsalis pedis pulse returned, but the left foot remained pulseless. Intraoperative angiography revealed occlusion of the left saphenous vein graft at the mid-popliteal level, and thrombectomy of the left popliteal and anterior tibial arteries allowed the retrieval of fresh clot. The tibial peroneal trunk was free of thrombus. Repeat angiogram showed a patent left anterior tibial artery. Postoperatively, the patient had sensory and motor loss in both legs, most marked at L5 on the left and S2 on the right. The first and second toes on her right foot were cyanotic, and there was a large area of skin necrosis over her left buttock. Ten days postoperatively, she developed acute peritonitis and free air underneath the diaphragm. Exploratory laparatomy disclosed necrosis of the dome of an anterior wall of the bladder and an ileal-vesicle fistula. Bladder debridement and ileal resection was followed by bladder repair, insertion of ureteral stents, and creation of an ileostomy. After removal of the ureteral stents and closure of the ileostomy, the patient convalesced without further complications. She still has a permanent sensory motor loss in her left lower extremity and is unable to ambulate.

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Case 2 A 63-year-old woman who had undergone a right femoropopliteal saphenous vein bypass graft 3 years previously, was admitted to the hospital with ischemic rest pain in her left foot. On admission, physical examination showed a blood pressure of 150/80 and femoral and distal pulses present on the right side, but absent on the left. Her left foot was cool, dark, and exquisitely tender. Angiography disclosed severe atherosclerotic aortoiliac stenosis with occlusion of both internal iliac arteries. After mobilization of the infrarenal aorta, the absence of previously present aortic and proximal common iliac pulses was observed. The patient was systemically anticoagulated with 7,000 units of intravenous heparin, and the blood pressure fell from 150/90 to 110/70 during the operation. The femoral arteries were exposed, and Fogarty thrombectomy enabled the retrieval of fresh thrombus from the common iliac, superficial femoral, profunda, and saphenous vein graft on the right. Forward runoff was obtained from the common iliac and back-bleeding from the femoral vessels. The distal vessels were then flushed with heparinized saline. On the left, forward flow from the iliac and back-bleeding from the superficial femoral and profunda were present prior to Fogarty thrombectomy, which did not retrieve any fresh thrombus. The distal vessels were flushed with heparinized saline. An aortobifemoral bypass graft was then performed. Intraoperative Doppler studies revealed bilateral popliteal pulses but absent pedal pulses. I ntraoperative femoral arteriograms showed flow through the trifurcation of the popliteal artery on the left and patency of the right femoral popliteal bypass graft without distal residual thrombus. By the second postoperative day, both legs appeared normal. All peripheral pulses could be palpated. The patient is currently ambulating without claudication but has required amputation of the first and fourth toes on her left foot.

Vol. 9, No. 1, March 1982

Discussion

Progressive atherosclerotic stenosis of arterial segments eventually results in central luminal thrombosis, completing the occlusive process. This rarely occurs in the aortoiliac region before the lumen has been narrowed by greater than 80% of the crosssectional area. Adequate collaterals usually develop with time. The terminal thrombosis is well tolerated and often clinically silent. In contrast, should the thrombosis occur prior to the development of adequate collateral circulation, sudden and severe ischemia develops. Acute thrombosis prior to terminal atherosclerotic narrowing develops in the setting of low cardiac output, sudden hypotension, or hypercoagulability. There is little clinical experience with acute aortic thrombosis. A prompt and aggressive surgical approach is necessary. The development of acute intraoperative aortic thrombosis during aortoiliac reconstructive surgery has not been previously reported. The condition should be suspected when there is a sudden loss of previously present aortic pulsations. The mechanism is related to a change in the blood flow characteristics in an atherosclerotic, critically stenotic aorta. Successful intraoperative management requires minimal delay from the time of thrombosis to recognition. This necessitates careful monitoring of the aortic pulse during the aortic dissection and mobilization. When the diagnosis is suspected, the patient should be systemically heparinized immediately. The common femoral vessels should then be exposed and Fogarty thrombectomy performed both antegrade and retrograde. The presence of backbleeding should indicate the adequacy of thrombectomy. Heparinized saline should then be flushed into all major vessels. Hypogastric thrombectomy should be per-

Texas Heart Institute Journal

formed in patients who have had preoperative patency of these vessels. Prior to completion of distal anastomoses, backbleeding should again be assessed and repeat thrombectomy performed if necessary. After flow to the lower extremities is reestablished, peripheral pulses should be assessed by palpation or Doppler recording. The use of intraoperative arteriography can show the presence of residual thrombus and patency of peripheral vessels to ensure extremity viability. Postoperatively, the patient should be carefully monitored for the possibility of visceral ischemia. In conclusion, acute infrarenal aortic thrombosis can be a catastrophic complication during aortoiliac reconstructive surgery. Evaluation of the aortic and iliac pulses prior to dissection along with frequent pulse evaluation should minimize the delay in diagnosis. Careful attention should be paid to factors that may lower blood flow or promote intravascular thrombosis. When acute thrombosis occurs, the patient should be systemically heparinized and Fogarty thrombectomy of the femoral and hypogastric vessels performed. Heparinized saline irrigation of all vessels should be done prior to clamping. After the reconstructive procedure is completed and flow to the extremities reestablished, intraoperative arteriography should be performed.

References 1. BellJW. Acute thrombosis of the subrenal abdominal aorta. Arch Surg 1967; 95:68 1. 2. Danto LA, Fry WVJ, Kraft RO. Acute aortic throm-

bosis. Arch Surg 1972; 104:569. 3. Matolo NMN, Cheung L, Albo D, Lazarus HM. Acute occlusion of the infrarenal aorta. Am J Surg 1973; 126:788. 4. Drager SB, Riles TS, Imparato AM. Management of acute aortic occlusion. AmJ Surg 1979; 138:293.

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