Aorto-uni-iliac endograft for complex aortoiliac aneurysms compared with tube/bifurcation endografts: results of the EVT/Guidant trials.

OBJECTIVE: Our objective was to present the results of the multicenter EVT/Guidant aorto-uni-iliac trial and to compare them with the tube, bifurcated graft, and open control series in regard to patient demographics, medical comorbidity, 30-day morbidity/mortality, and outcome at 1 year. METHODS: One hundred twenty-one patients not eligible for tube or bifurcated endografts were entered into the aorto-uni-iliac trial (A-I). These were compared with 153 patients in a tube (T) group, 268 patients in a bifurcated endograft (BI) group, and 111 patients in an open control (C) group. All data were audited and independently analyzed for presentation to the Food and Drug Administration. RESULTS: Group demographics were similar with the following exceptions. Aneurysm diameter was significantly less in the T group (51.2 mm) but similar for the A-I (57 mm), BI (54.6 mm), and C (55.6 mm) groups (P < .001). There were more male patients in all endograft groups (A-I 92.6%, BI 89.5%, T 85.6% vs 76.6% for C, P = .002). Peripheral arterial occlusion was present more frequently in the A-I group (25.6% vs 13.8% BI, 10.5% T, and 10.8% C, P = .003). However, no differences were found in mean age, incidence of coronary artery disease, and American Society of Anesthesiologists III/IV classification. Implantation was achieved in 94.2% of the A-I group, 90.3% of the BI group, and 92% of the T group. No significant difference was seen in the operative mortality rate (4.2% A-I, 2.6% BI, O% T, 2.7% C). Postoperative cardiac complications were similar for the A-I (22%) and C (20.7%) groups but significantly less for the BI and T groups (13.4% and 10.5%, P = .019), whereas pulmonary problems were significantly reduced in all endograft groups (A-I 11.9%, BI 10.1%, and T 7.2% vs 22.5% for C, P = .002). Transient renal dysfunction occurred in 6.8% of the A-I group and 8.2% of the BI group but in only 3.3% of the T group and 1.8% of the C group (P = .028). Operating time was significantly longer for the A-I group than for the BI, T, or C groups (258 minutes vs 156, 179, and 174 minutes). Median blood loss, intensive care unit use, and hospital stays were markedly and significantly reduced in all endograft groups compared with the control group. The incidences of type I endoleak at 1 year were 2.4% A-I, 2.3% BI, and 3.8% T, and no ruptures occurred in any of the patients treated with endografts. No femoral-femoral graft thromboses occurred in the A-I group. CONCLUSION: Despite the fact that patients with combined aortic and iliac aneurysms have a more complex repair requirement and have an increased rate of comorbidity, the results are competitive with endovascular repair of aortic aneurysm by tube and bifurcated graft systems and are associated with a lower morbidity than open operation.

Endovascular treatment of abdominal aortic aneurysms.

Abdominal aortic aneurysms (AAA) may now be treated by endovascular placement of an arterial graft. These grafts are inserted through the femoral artery and then secured to the aorta above and below the aneurysm. The procedure reduces the risk of many perioperative complications and reduces hospital costs and length of stay. Several FDA-approved clinical trials are currently in progress with a variety of different devices. None is available for general use at this time. Overall, more than 800 grafts have now been placed, with a primary success rate of greater than 80%. Several complications have been reported, but the incidence of complications has generally decreased as proficiency has improved. The most troublesome problem has been leak of blood around the graft with continued risk of aneurysm rupture; therefore, follow-up CT scans and clinical examinations are mandatory to allow for appropriate treatment. Future modifications of current devices and techniques for delivery can be expected to reduce the incidence of currently identified problems. Endovascular grafting for AAA offers important potential advantages over conventional repair and may become increasingly important in the management of patients who have an abdominal aortic aneurysm.

Clinical and CT evaluation of a new stretch polytetrafluoroethylene aortic graft.

A new stretch polytetrafluoroethylene (PTFE) aortic graft became available for clinical use in early 1991. We prospectively evaluated our first 107 stretch aortic PTFE grafts by means of serial CT imaging and compared them with a cohort of concurrently placed Dacron grafts. Stretch PTFE requires no preclotting and is claimed to resist long-term dilation and conform well to anastomoses. Consecutive patients undergoing placement of stretch PTFE grafts were seen at least yearly. Within the first 2 years after implantation, contrast-enhanced CT scans of the abdomen and pelvis were obtained. Caliper measurements were made of the native arteries and the body and any limbs of the aortic grafts. Graft elongation was assessed by noting distortions from the normally circular or minimally ovoid configuration of the grafts on transverse CT images. Indications for grafting were elective repair of abdominal aortic aneurysm in 60 patients, aortoiliac occlusive disease in 31, both aneurysm and occlusive disease in eight, and ruptured abdominal aortic aneurysm in eight. The overall operative mortality rate was 6.5%. There were two early postoperative graft limb thromboses resulting from hypercoagulable states, and there was one graft infection. Mean follow-up was 14.1 months (range 1 to 34 months). CT scans were obtained from 61 patients with stretch PTFE grafts and 10 with concomitantly placed Dacron grafts. Ten patients had two or more postoperative CT scans. Primary stretch PTFE patency was 98% and secondary patency, 100%. There was significantly less dilation of both the graft body and limbs in the stretch PTFE group (body mean 16.5%, range 6.3% to 28.1%; limb mean 19.3%, range 10% to 43%) compared to the Dacron group (body mean 33%, range 22% to 78%; limb mean 62%, range 12.5% to 88.9%) (p < 0.01, unpaired t test).(ABSTRACT TRUNCATED AT 250 WORDS)

Application of computed tomography for surveillance of aortic grafts.

BACKGROUND: This study was undertaken to assess the application of computed tomography (CT) for surveillance of aortic grafts. METHODS: Demographics, operative technique, and graft type and size at the time of implantation of aortic grafts in 178 patients were recorded. CT measurements of graft diameters were made with calipers. Data were analyzed by analysis of variance, multiple regression, and chi-squared methods. RESULTS: One hundred twenty-eight (72%) bifurcated grafts and 50 (28%) tube grafts were placed for aneurysmal disease (49%), aortoiliac occlusive disease (47%), ruptured aneurysm (2.3%), anastomotic aneurysm (1%), and graft aneurysm (0.6%). Mean implant time was 43.3 +/- 3.2 months. A total of 143 Dacron prostheses (74 woven, 69 knitted) and 35 polytetrafluoroethylene prostheses were placed. Mean percentage dilation was 49.2 +/- 4.0 for knitted prostheses, 28.5 +/- 3.0 for woven prostheses, and 20.6 +/- 1.9 for polytetrafluoroethylene prostheses compared with the graft implant size. A significant correlation was seen between graft dilation (more than 50%) and graft construction with knitted prostheses (p < 0.01, Tukey's range test). Complications detected by CT occurred in 24 (13.5%) patients including supragraft aneurysms (seven), distal anastomotic aneurysms (five), proximal anastomotic aneurysms (three), graft infections (two), perigraft fluid collections (two), graft aneurysm with thrombus and distal embolization (two), and nonvascular complications (three). CONCLUSIONS: CT is a useful modality for postoperative imaging of aortic prostheses. Routine surveillance may detect complications before they become clinically apparent.

Aortofemoral graft occlusion: strategy and timing of reoperation.

The authors' experience with 46 patients treated over 8.5 years was reviewed to determine the optimal secondary revascularization procedure after occlusion of a unilateral aortobifemoral graft limb. A total of 64 procedures was performed on these patients to restore and maintain graft patency. Repetitive operations for reocclusion were needed in 14 patients (30%). Transcatheter thrombolytic therapy was used in 14 patients, four as sole therapy and 10 in conjunction with operation. The mean time from aortofemoral grafting to presentation with graft limb occlusion was 59.4 months. Rest pain or severe ischemia was present in 85%, and severe claudication in the remainder. Some 78% had urgent operation after diagnostic angiography and catheter-directed thrombolytic therapy was attempted in 22%. The etiology of graft thrombosis was outflow obstruction in 78.2% of cases. Inflow was obtained by surgical thrombectomy in 35 and by lytic therapy in 13. Extra-anatomic inflow was used in 11 and intra-abdominal thrombectomy or redo aortofemoral grafting in five. Outflow procedures, mainly profundaplasty, were performed in all but five cases (four urokinase and one surgical). Infrainguinal bypass was needed in 10 cases in addition to the groin reconstruction. Catheter-directed thrombolysis was successful in 13 of 14 instances; however, in nine of these residual stenosis was disclosed in the outflow requiring surgical repair. Ultimately, 12 of 14 cases treated with thrombolysis required surgical intervention. Cumulative patency for all procedures was 68%. Complications were seen in 14% of cases. Operative mortality was 5%, and limb salvage was obtained in 85%.(ABSTRACT TRUNCATED AT 250 WORDS)

MR angiography of the foot and ankle.

To better understand the use of magnetic resonance angiography (MRA) in evaluating peripheral vascular disease, the authors studied arteries in the foot and ankle. Twenty patients with arterial occlusive disease of the lower extremity were studied with two-dimensional time-of-flight MRA, and the results were compared with those of 10 conventional x-ray arteriograms, four digital subtraction arteriograms, and three intraoperative arteriograms. The studies were reviewed and rated by three radiologists blinded to the patients' clinical history. Also, the first 16 patients were examined with MRA before and after intravenous injection of gadopentetate dimeglumine. The mean confidence levels for the reviewers' interpretations of the MRA studies were significantly higher than those for the conventional arteriograms for the medial plantar, lateral plantar, and plantar arch arteries of the feet (P < or = .005). Postcontrast MRA images were inferior to precontrast images because of overlapping of veins and arteries. Time-of-flight MRA without gadolinium can serve as a useful complementary study for evaluating patients with peripheral vascular disease in the foot and ankle.

Popliteal vascular compression in a normal population.

PURPOSE: Positional popliteal artery obstruction is believed to be an important factor contributing to popliteal artery entrapment syndromes. This study was undertaken to define the positional anatomy and physiologic condition of the vessels in the popliteal fossa in groups of highly trained and normally active young men and women. We postulate that at least some symptom-free individuals can occlude the popliteal artery with leg positioning. METHODS: Seventy-two limbs were evaluated in 36 subjects. Symptom-free subjects were recruited in four groups: normally active men, normally active women, male competitive runners, and female competitive runners. All subjects underwent noninvasive testing that included resting segmental limb pressures and Doppler waveforms and color-flow duplex imaging with the leg in the neutral position and then with knee extension with active and passive dorsiflexion and plantar flexion of the foot. Subjects unable to occlude the popliteal artery with positioning were then exercised, and studies were repeated. Magnetic resonance imaging, with magnetic resonance angiography, was conducted on 14 subjects, with each leg studied in the neutral position and with active positioning. RESULTS: Positional popliteal arterial occlusion occurred in 38 of 72 limbs (53%). No intergroup comparisons were statistically significant. The response of each leg was symmetric in 89% of subjects. No subject who could not occlude the popliteal artery at rest was able to do so with exercise. Magnetic resonance imaging disclosed normal anatomy in all subjects and showed the location of popliteal occlusion to be at the level of the soleal sling, with positional compression by the soleus muscle, the lateral head of the gastrocnemius, the plantaris, and popliteus muscles. CONCLUSION: Popliteal arterial occlusion can be induced in 53% of subjects with simple leg positioning caused by myofascial compression. This must be considered when evaluating patients for intervention on the basis of physiologic testing of the popliteal vessels.

Aortic graft infection due to Pasteurella haemolytica and group C beta-hemolytic streptococcus.

Although infection is a rare complication of aortic bypass grafting, we treated a 50-year-old patient who developed aortic graft infection due to Pasteurella haemolytica and group C beta-hemolytic streptococcus. The source of the infection could not be verified; however, after removal of the infected graft and administration of a 6-week course of intravenous ampicillin, he recovered fully. We discuss the etiology and pathogenesis of this rare infection.

Critical carotid artery stenosis: diagnosis, timing of surgery, and outcome.

PURPOSE: Patients with critical carotid artery stenoses have been considered to be at high risk for carotid artery occlusion necessitating urgent or emergency endarterectomy once the stenosis is identified. Included in this group of patients are those with carotid string sign or atheromatous pseudoocclusion (APO). This review was conducted to determine the impact of the severity of stenosis including APO on the treatment and outcome of patients undergoing carotid endarterectomy. METHODS: The records of 203 consecutive carotid endarterectomies performed in 197 patients were reviewed in detail. Patients were stratified into a critical stenosis group (80% to 99% diameter) and noncritical stenosis group based on noninvasive vascular laboratory and carotid arteriography results. Comparisons were performed of demographic data, atherosclerotic risk factors, carotid artery disease presentation, interval between arteriography and endarterectomy, operative details, and surgical results between the critical and noncritical groups and between patients in the critical group with and without APO. RESULTS: Carotid endarterectomies were performed on 91 critical carotid artery stenoses and 112 noncritical stenoses. The groups did not differ significantly with regards to demographics, risk factors, carotid artery disease presentation, mean back pressure, and operative use of shunt or patch closure. For the critical group the interval between arteriography and endarterectomy was 8.63 +/- 2.38 days compared with 9.64 +/- 2.14 days for the noncritical group (mean +/- SEM, p = 0.75). No patient in either group progressed to occlusion in the interval between arteriography and endarterectomy. Perioperative strokes occurred in two patients (2%) in the critical group and four patients (3.6%) in the noncritical group (p = 0.09). Likewise, no significant difference was demonstrated in these variables when comparing patients with critical carotid artery stenosis and APO with those without APO. CONCLUSIONS: The presence of a critical carotid artery stenosis including APO did not impact on the treatment or outcome of patients requiring endarterectomy nor did it imply the need for emergency intervention to prevent thrombosis. Surgical intervention can proceed after evaluation and optimization of comorbid conditions without undue concern for interval thrombosis.

The effects of improved hemodynamics on aortic dimensions in patients undergoing heart transplantation.

PURPOSE: Retrospective studies have demonstrated an accelerated growth rate of abdominal aortic aneurysms in heart transplant patients. This prospective study was undertaken to define the relationship between cardiac hemodynamics and posttransplant aortic dilation. METHODS: Sixty-eight patients undergoing heart (n = 60) or heart-lung (n = 8) transplantation were prospectively evaluated with abdominal ultrasonography before transplantation and annually after transplantation. Risk factors implicated in aneurysm growth, including age, indication for transplantation, immunosuppression, posttransplantation hypertension, and abdominal aortic dimension before transplantation were recorded. All patients underwent annual coronary artery catheterization and multiple gated acquisition scanning. RESULTS: Thirty-seven patients (54%) had no change in aortic diameter after transplantation (pretransplantation and posttransplantation diameter = 1.8 +/- 0.3 cm), over a mean follow-up period of 28 +/- 14 months. In the remaining 31 (46%) patients, aortic diameter increased by 0.5 +/- 0.6 cm over 31 +/- 15 months (p < 0.05). Four (6%) of these 31 patients had abdominal aortic aneurysms (mean aortic diameter = 5.0 +/- 0.8 cm). The mean increase in aortic diameter among these 4 patients was 1.8 +/- 0.2 cm (annual rate of growth = 0.96 +/- 0.3 cm/year). Patients experiencing an increase in aortic dimension after transplantation had significantly lower (p < 0.005) pretransplantation ejection fractions (17.1% +/- 10.5% vs 28.6% +/- 18.1%) and, as a consequence, significantly greater (p < 0.05) increases in their ejection fractions after transplantation compared with patients with stable aortic dimensions (42.7% +/- 12.6% vs 31.8% +/- 18.0%). CONCLUSIONS: Of 68 heart transplant patients prospectively evaluated, aortic diameter increased in 31 (46%); new aneurysms developed in four of these patients. Greater incremental increases in cardiac ejection fraction were significant correlates with aortic enlargement.

Catheter-directed urokinase thrombolysis: an adjunct to PTA/surgery for management of lower extremity thromboembolic disease.

Catheter-directed thrombolysis was used either alone or as an adjunct to percutaneous transluminal angioplasty (PTA) or surgery for peripheral vascular occlusion on 112 occasions in 102 patients. Symptom duration ranged from < one to > twenty-eight days. Thrombolytic therapy using urokinase plasminogen activator thrombolysis (uPAT), including intrathrombic injection when possible, was successful (> 50% lysis) in 99 procedures (88%). Technical failure (< 50% lysis) occurred in 13 procedures (12%). In 9 of the 13 failures, intrathrombic injection of urokinase was not possible, but the duration of occlusion was > twenty-eight days in all but 1. Two other failures were from embolic sources and 2 more occurred in patients with a hypercoagulable state. The uPAT was adjunctive to PTA/surgery in 56 cases (50%). PTA following uPAT was required and successfully performed in 24 of 27 cases (88.9%). Surgery followed lytic therapy in another 32 (including the 3 failed PTAs). In the remaining 56 cases (50%), no additional intervention was required. There were 20 complications (18%), minor in 16 of 20 (80%). Minor complications included small puncture site hematomas and distal embolization resolved by continued lytic therapy. Four major complications occurred. One was retroperitoneal hemorrhage directly contributing to the only death in the series. The other 3 were hematuria (2) and femoral neuropathy (1). The authors conclude that catheter-directed lytic therapy alone or as an adjunct to PTA/surgery is a valuable approach to peripheral vascular thromboembolic disease. It is less likely to succeed in chronic occlusion. The incidence of complications is moderate but acceptable.

Shoelace technique for delayed primary closure of fasciotomies.

Performing a timely fasciotomy for compartment syndrome prevents ischemic injury to muscles and nerves. Fasciotomy entails incision of the overlying skin and investing fascia of the compartment, relieving pressure and enhancing tissue perfusion. Delayed primary closure is ideal, but because of skin edge retraction, the open wound must either heal secondarily or be closed with a split-thickness skin graft. The shoelace technique involves running a silastic vessel loop through skin staples placed at the skin edge along the initial fasciotomy incision. Daily tightening of the shoelace permits gradual reapproximation of the skin edges while compartment edema resolves. Closure using a simple suture or Steri-strip (3M Surgical Products, St. Paul, Minnesota) is then possible after 5 to 10 days. The shoelace technique allows for gradual primary closure of open fasciotomy wounds, thereby avoiding the morbidity and cost associated with skin graft or secondary closure.

Management of chyloperitoneum after abdominal aortic surgery.

Chyloperitoneum is a rarely reported complication of abdominal aortic surgery. From 1981 to 1992, we treated 5 cases of chylous ascites after operations on the abdominal aorta and reviewed 22 previously published cases. There were 22 men and 5 women, with a mean age of 63.8 years (range: 27 to 93 years). Twenty cases (74.7%) occurred after abdominal aortic aneurysm resection, 5 (18.5%) after aorto-femoral bypass for occlusive disease, and 2 (6.8%) after resection of infected aortic grafts, 1 for occlusive disease and the other for infrarenal aortic aneurysm. Abdominal distention was the most common presenting symptom, occurring in 26 (96.3%) of 27 patients. The mean time from aortic operation to the development of symptoms was 18.5 days (range: 7 to 120 days). Diagnosis was confirmed by paracentesis, which yielded lipemic, sterile fluid in all patients. Therapeutic paracentesis was not successful when used alone, but, when combined with a medium-chain triglyceride (MCT) diet or total parenteral nutrition (TPN), it resulted in resolution of chyloperitoneum in 8 of 14 patients (57.2%). TPN alone or with paracenteses and/or diuretics was successful in 9 of 15 (60%) patients. Peritoneovenous shunts resolved chylous ascites in four of five patients not responding to diet and/or TPN but resulted in one death due to sepsis. Operative ligation of the injured lymphatic channel was successful in all five patients treated by laparotomy when nonoperative efforts failed. Chyloperitoneum resolved in all but two (7.7%) patients. There were five (18.5%) deaths, but only three (11.5%) were directly related to chylous ascites. Treatment with TPN resolved chyloperitoneum in all five of our own patients. We reached the following conclusions: (1) Chyloperitoneum is a rare complication of aortic surgery; (2) This disorder should be considered whenever persistent abdominal distention appears after aortic surgery; (3) The diagnosis is easily confirmed by paracentesis; and (4) Surgery to close the lymph fistula should be reserved for those patients in whom conservative therapy with MCT diets or TPN has failed.

Risk factors for stroke in patients undergoing coronary artery bypass grafting.

Stroke is a significant cause of morbidity and mortality following coronary artery bypass grafting (CABG). Over a 30-month period, 245 consecutive patients undergoing elective CABG were prospectively examined to determine which risk factors might predispose to stroke following surgery. The risk factors evaluated included hypertension, diabetes, hypercholesterolemia, hypertriglyceridemia, smoking, atrial fibrillation, a history of cerebrovascular accident or transient ischemic attack, carotid artery stenosis > 60% documented by duplex scanning, severe atherosclerosis of the ascending aorta, and the presence of ventricular thrombus. Postoperative stroke occurred in five of the 245 patients (2%), four evident immediately on awakening and one on day 7 after surgery. The probable causes of the immediate strokes were atheroembolism in three patients and severe ipsilateral carotid stenosis in one. Hypertensive hemorrhage was responsible for the one case of delayed stroke. In this study, carotid artery stenosis did not presage stroke following CABG, but ventricular thrombus was highly predictive of stroke after surgery.

Hepatic ischemia, caused by celiac axis compression, complicating pancreaticoduodenectomy.

OBJECTIVE: In the course of pancreaticoduodenectomy, profound hepatic ischemia developed in two patients (one with ampullary carcinoma, the other with chronic pancreatitis). This article addresses the diagnosis and correction of the celiac axis compression responsible in this complication. SUMMARY BACKGROUND DATA: Since hepatic ischemia appeared immediately after division of the gastroduodenal--pancreaticoduodenal arcade, which provides mesenteric to celiac collateral circulation, celiac axis narrowing or occlusion was suspected. Previous reports have indicated that celiac axis disease may be present in about 10% of such patients. METHODS: Doppler flow studies, and in the second patient, intraoperative angiography were performed. The celiac axis was exposed and mobilized in both. RESULTS: Initially, no flow could be detected in the celiac axis. Dense fibrous tissue was found encasing it. Division of the entrapping tissue restored flow to the upper abdominal viscera. CONCLUSIONS: The anatomic deformation of the celiac axis predisposing to this complication is detectable on the lateral projection of a preoperative celiac angiogram. If, however, an angiogram has not been done, an initial test occlusion of the gastroduodenal artery before its division permits anticipation of the complication, correction of the celiac impingement, and hence, avoidance of hepatic ischemia.

Thrombectomy and isolated limb perfusion with urokinase in the treatment of phlegmasia cerulea dolens.

Phlegmasia cerulea dolens is a rare form of deep vein thrombosis. A patient with recurrent episodes of such thrombosis caused by protein C deficiency who developed phlegmasia cerulea dolens is reported. Limb perfusion with urokinase successfully restored venous outflow after unsuccessful attempts at thrombectomy.