Challenges of hemodialysis access for high risk patients: Impact of mesenteric vein bioprosthetic graft.

OBJECTIVE: The purpose of this study is to compare in a prospective fashion the performance of a new bioprosthesis, the mesenteric vein bioprosthesis (MVB), in patients who have had multiple failed ePTFE grafts. Performance measures include primary patency rates, assisted-primary patency rates, secondary patency rates, complications, and the number of interventions required to maintain graft patency. STUDY: From October 1999 to February 2002, 276 hemodialysis access grafts were implanted in a multicenter study. Of those grafts, 74 were placed in patients with a prior history of 3 failed prosthetic grafts (mean = 3.5 grafts, range = 3-6 grafts). Fifty-nine grafts were constructed with MVB, and 15 grafts with ePTFE as a concomitant control. Mean follow-up was 11.5 months. In the MVB group, 79.7% were African-Americans, 61% were females, and 23.7% were hypercoagulable. Of the ePTFE group, 86.7% were African-Americans, 46.7% were female, and 13.2% were hypercoagulable. Results : Per Kaplan-Meier curves, the primary patency rate of the MVB group at 12 months was 33% vs the ePTFE group of 18% (p=0.120); the assisted-primary patency rates at 12 months were 45% MVB vs 18% ePTFE (p=0.011). The secondary patency rates at 12 and 24 months for the MVB group were 67% and 59%, respectively, vs 45% and 15% for the ePTFE group (p=0.006). During the follow-up time period, 80% of the ePTFE grafts were abandoned compared to 34% of the MVB group. Infection and thrombosis rates in the MVB group were lower than the ePTFE group. The infection rate for the MVB group requiring intervention was 0.07 events/graft year (gt/y) compared to 0.30 events/gt-y for ePTFE (p=0.04). A thrombosis rate of 0.69 events/gt-y occurred in the MVB group whereas 2.50 events/gt-y presented in the ePTFE group (p<0.01). CONCLUSION: In this study, high-risk patients (defined as those having multiple failed prosthetic grafts for hemodialysis) in whom the MVB conduit for hemoaccess was implanted, showed significant improvement in assisted-primary and secondary patency rates compared to the ePTFE cohort. The MVB group, however, did not have a statistically better primary patency rate compared to the ePTFE group. The MVB patient also had fewer thrombotic and infectious events and an overall reduction in the number of interventions while maintaining a permanent access site. This new bioprosthesis should be the conduit of choice in the complex group of patients as it offers assisted-primary and secondary patency rates similar to those commonly experienced by patients without a history of multiple graft failures.

Screening and preoperative imaging of candidates for carotid endarterectomy.

Randomized clinical trials have provided us with clinical guidelines regarding the indications for performing carotid endarterectomy in patients who have symptomatic and asymptomatic disease. Logically, any patient with a history of transient ischemic attacks, amaurosis fugax, or stroke should be evaluated for extracranial carotid artery occlusive disease. In asymptomatic patients, however, carotid artery surveillance may be helpful in identifying those at risk before neurological events. Patients at particularly high risk include those identified with (1) manifestations of systemic atherosclerotic disease (peripheral vascular disease, coronary artery disease, renovascular disease); (2) presence of a carotid bruit; (3) advanced age (> 65 years); and (4) ABI less than 0.7. Duplex ultrasonography remains the best and most widely used noninvasive screening method, but its accuracy is highly technologist dependent. A high-quality duplex study may, in itself, be adequate to determine whether the severity of extracranial carotid occlusive disease warrants surgical intervention. Catheter-based arteriography may be used as an adjunct to validate duplex results, but its invasive nature and risk of complications has popularized alternative imaging methods. Of these, magnetic resonance angiography (MRA) and spiral computed tomographic angiography (CTA) show excellent promise as noninvasive imaging techniques for the evaluation of extracranial carotid artery occlusive disease.

Systemic treatment of venous leg ulcers with high doses of pentoxifylline: efficacy in a randomized, placebo-controlled trial.

Several small studies have indicated that the systemic administration of pentoxifylline may accelerate healing of venous leg ulcers. The goal of this study was to further evaluate these findings in a larger scale placebo controlled trial and to explore the effect of the dose of pentoxifylline on healing. The study used a prospective, randomized, double-blind, parallel group placebo controlled design in a multicenter outpatient setting. Patients with one or more venous ulcer were enrolled, with all patients receiving standardized compression bandaging for treatment for their ulcers. Patients were also randomized to receive either pentoxifylline 400 mg, pentoxifylline 800 mg (two 400 mg tablets), or placebo tablets three times a day for up to 24 weeks. The main outcome measure was time to complete healing of all leg ulcers, using life table analysis. The study was completed as planned in 131 patients. Patients receiving 800 mg three times a day of pentoxifylline healed faster than placebo (p = 0.043, Wilcoxon test). The median time to complete healing was 100, 83, and 71 days for placebo, pentoxifylline 400 mg, and pentoxifylline 800 mg three times a day, respectively. Over half of all patients were ulcer free at week 16 (placebo) and at week 12 in both pentoxifylline groups. Whereas the placebo group had only achieved complete healing in half of the cases by week 16, all of the subjects remaining in the group receiving the high dose of pentoxifylline had healed completely. Treatment with pentoxifylline was well tolerated with similar drop-out rates in all three treatment groups. Complete wound closure occurred at least 4 weeks earlier in the majority of patients treated with pentoxifylline by comparison to placebo. A higher dose of pentoxifylline (800 mg three times a day) was more effective than the lower dose. We conclude that pentoxifylline is effective in accelerating healing of leg ulcers.

Preoperative testing before carotid endarterectomy: a survey of vascular surgeons' attitudes.

Traditional surgical practice and published consensus statements from major vascular surgery specialty societies have considered contrast arteriography to be a routine part of the diagnostic evaluation prior to carotid endarterectomy (CEA). However, some surgeons now omit routine preoperative arteriography if a technically adequate carotid duplex scan is performed and indications for CEA are clear. To better establish current practice patterns and to characterize vascular surgeons' opinions about the role of preoperative arteriography, the Peripheral Vascular Surgery Society membership was surveyed by mail. Eighty-six percent of the members responded (430 of 502). Ninety-three percent of all patients considered for CEA are evaluated with duplex scanning; 82% with arteriography. While the majority of surgeons typically obtain both a duplex scan and an arteriogram, 70% have performed CEA without a preoperative arteriogram. Brain imaging studies (CT or MRI) are obtained in 26% and MR angiograms in 10% of cases. Seventy-five percent of the surgeons agreed with the statement that CEA without preoperative arteriography is an acceptable practice if appropriate indications for surgery are present. Furthermore, one third believed that CEA without a preoperative arteriogram is generally acceptable (acceptable more than half the time). Respondents were stratified by surgical experience time in practice and practice type. No significant differences in responses were found, suggesting the acceptance of CEA without preoperative arteriography is broad-based. This survey demonstrates changing attitudes among practicing vascular surgeons regarding the necessity for routine arteriography prior to CEA. Carotid endarterectomy on the basis of duplex scanning and clinical assessment should be considered an accepted alternative.

Stent deformation and intimal hyperplasia complicating treatment of a post-carotid endarterectomy intimal flap with a Palmaz stent.

We report a case of common carotid artery Palmaz stent placement for treatment of an intimal flap after surgical endarterectomy. Despite technical success with an excellent immediate result, a significant stenosis detected by duplex sonographic examination developed at 10 months. This stenosis, the result of stent compression and intimal hyperplasia, illustrates the previously theoretic risk associated with placement of the balloon-expandable stent in a compressible site such as the cervical carotid artery. In addition, we demonstrate that significant intimal hyperplasia may occur after carotid artery stent placement, potentially limiting long-term patency.

Utility of routine carotid duplex screening in patients who have claudication.

PURPOSE: The recently published Asymptomatic Carotid Atherosclerosis Study (ACAS) demonstrated the benefit of performing carotid endarterectomy in selected asymptomatic patients who have > 60% carotid stenoses. It therefore becomes clinically important to identify the subgroups of patients who have a sufficiently high incidence of high-grade carotid stenosis to warrant routine carotid duplex screening. METHODS: To determine the incidence of asymptomatic carotid disease in patients who had a chief complaint of claudication, we evaluated 188 patients who had claudication and no history of cerebrovascular symptoms. After a complete history was taken and a physical examination performed, patients underwent standard lower-extremity noninvasive vascular laboratory studies and carotid duplex scanning. Carotid duplex findings were interpreted by the Strandness criteria. Associated atherosclerotic risk factors were assessed (patient age, male sex, diabetes, hypertension, smoking history, lipid levels, history of coronary artery disease, coronary or vascular surgery, and family history of cerebrovascular disease). Presence of a carotid bruit was also noted. Univariate analysis, logistic regression, and odds ratios were performed to identify subgroups of patients that had an increased incidence of significant carotid disease. RESULTS: Of the 188 patients with claudication who were screened, 8% had an internal carotid artery stenosis of 16% to 49%, 21.8% had a stenosis that exceeded 50%, and 2.7% had an occluded internal carotid artery. The presence of a carotid bruit on physical examination was predictive of a > or = 50% internal carotid artery stenosis (p = 0.027). The ankle-brachial index was highly predictive of the presence of carotid stenoses in an inverse relationship (p = 0.001). Patient age approached significance (p = 0.143). Patients older than 65 years of age who had claudication, an ankle-brachial index less than 0.7, and a carotid bruit had a 45% incidence of significant carotid disease. The atherosclerotic risk factors of male sex, diabetes, hypertension, hyperlipidemia, smoking history, coronary history, previous coronary or vascular surgical history, and family history were not predictive of the presence of a > 50% carotid stenosis. CONCLUSIONS: In patients who seek medical attention with the chief complaint of claudication and who have no cerebrovascular symptoms, there is a 24.5% incidence of a > 50% internal carotid artery stenosis or occlusion on duplex examination. Select subsets of these patients have upwards of a 45% incidence of significant asymptomatic carotid disease. All patients who seek medical attention with claudication should therefore undergo routine carotid duplex screening to detect asymptomatic high-grade stenosis.

Surgical methods for renal revascularization.

The availability of newer treatment alternatives for patients with renovascular disease has resulted in many patients being referred for surgical intervention in a delayed fashion. As a result of these changes in the type of patients being referred to surgery with more advanced renovascular hypertension and renal excretory dysfunction, vascular surgeons need to be well versed in the variety of surgical renal revascularization techniques. Each of the procedures has its own advocates, but many of these techniques are not applicable in all patients. Familiarity with the various techniques allows the surgeon to have a choice in the method of renal revascularization appropriate for a given clinical situation. Ultimately, the efficacy of any interventional procedure must be considered along with its associated morbidity, mortality, and long-term clinical outcome. All become important factors when considering the optimal primary surgical procedure to treat the patient with renovascular hypertension or renal excretory dysfunction.

The utility and durability of vein bypass grafts originating from the popliteal artery for limb salvage.

BACKGROUND: Short vein grafts originating from sites distal to the common femoral artery have been reported to be useful in selected patients with tibial artery disease. From 1987 to 1993, we performed 504 consecutive infrainguinal vein bypass grafts, of which 56 (11%) originated from the popliteal artery, 25 above and 31 below the knee. PATIENTS AND METHODS: The patients were 16 women and 37 men, with a mean age of 62.4 years. Eighty-seven percent were diabetic, 57% had clinically obvious coronary artery disease, and 28% had end-stage renal disease (ESRD). The indication for surgery was ulceration or gangrene in 93% of cases. We preferentially used reversed greater saphenous vein harvested from the thigh to optimize conduit quality and avoid lower leg wound complications. The outflow artery sites were: dorsal pedal (17), posterior tibial (14), peroneal (10), anterior tibial (8), lateral or medial plantar (5), and sequential tibial (2). All patients were followed postoperatively with serial duplex surveillance. The mean follow-up was 12.5 months (range 1 to 66). RESULTS: In-hospital mortality was 5.4%. Mortality at 24 months was 19% overall and 38% in patients with ESRD. Limb salvage was 77% at 3 years, 92% in patients with normal renal function versus 59% in those with ESRD (P < 0.003). Primary graft patency by life-table analysis was 94% at 1 month and 84% at 3 years. Five patients with patent grafts required amputation, 4 early and 1 late. Eight months after surgery, 1 patient (1.8%) developed superficial femoral artery stenosis which was diagnosed by duplex surveillance and successfully treated by percutaneous transluminal balloon angioplasty. CONCLUSIONS: Vein bypass grafts originating from the popliteal artery are effective and durable. Proximal disease progression rarely poses a significant threat to long-term graft patency. Patients with ESRD, blind tibial outflow tracts, and extensive forefoot lesions appear to be at increased risk of limb loss even with continued graft patency.

Does infrapopliteal arterial runoff predict success for popliteal artery aneurysmorrhaphy?

BACKGROUND: A 6-year experience with surgical management of popliteal artery aneurysms (PAAs) was examined to determine the influence of infrapopliteal outflow vessel patency on the long-term success of popliteal artery aneurysmorrhaphy. METHODS: Arteriograms were reviewed to characterize the anatomy of the infrapopliteal arterial runoff. Regular clinical evaluation and prospective serial duplex scan surveillance assessed graft patency. RESULTS: A total of 28 patients underwent 45 popliteal aneurysmorrhaphies. Elective repair was performed in 32 limbs (71%); emergency treatment was needed for 13 limbs (29%) because of acute limb-threatening ischemia. All patients were managed with PAA exclusion and reversed saphenous vein grafting. Only 20 limbs (44%) had a patent trifurcation with three continuous vessels to the ankle, 13 (29%) had two continuous tibial vessels, 10 (22%) had one patent runoff artery, and 2 (4%) had no vessel continuous to the foot. With a mean follow-up of 19.1 months, the 5-year primary graft patency by life-table analysis was 95 +/- 12.3%, with a 5-year assisted primary patency of 97 +/- 10.0%. One vein graft underwent elective secondary revision. Another graft thrombosed, requiring a secondary bypass. Outcome did not correlate with the status of the runoff anatomy. Limb salvage was 100%. CONCLUSION: The use of autologous reversed vein grafting and attention to technical details yielded normal graft hemodynamics and excellent long-term patency and limb salvage despite the suboptimal runoff anatomy associated with PAAs.

The juxtarenal abdominal aortic aneurysm. A more common problem than previously realized?

OBJECTIVE: To determine the incidence and treatment outcome of juxtarenal infrarenal aneurysmectomy in a vascular practice minimally biased by tertiary referral. DESIGN: A 5-year retrospective review of all aortic operations from our vascular registry was performed, and a case series of juxtarenal aneurysmectomies was analyzed. PATIENTS: Of 174 infrarenal aortic aneurysmectomies performed, 27 (15.5%) (95% confidence interval, 10.5% to 21.8%) involved the juxtarenal aorta. INTERVENTIONS: Juxtarenal involvement was unsuspected but found by aortography in 25 (93%) of 27 cases. Resection was performed transabdominally in 20 cases (74%) and retroperitoneally in seven cases (26%). MAIN OUTCOME MEASURES: Incidence, operative technique, morbidity, and mortality were analyzed and compared with those of historical controls. RESULTS: The incidence of juxtarenal aneurysmectomy was 15.5%. No operative deaths occurred, but there was a 19% incidence of surgical morbidity (including a 7% incidence of transient renal failure). The late survival rate was 89% (follow-up, 1 to 53 months; mean, 18 months). CONCLUSIONS: Juxtarenal aortic aneurysms are not uncommon. Successful management is possible, even outside the large referral center.

Vascular grafts in head and neck reconstructive surgery.

The best management of advanced head and neck tumors invading the carotid artery utilizes a collaborative, anticipatory approach. Preoperative characterization of the anatomy and extent of tumor involvement, coupled with the physiologic assessment of the cerebrovascular circulation through the variety of adjunctive studies, facilitates operative planning. Careful preoperative evaluation allows the surgeon to make the most informed decision regarding extracranial carotid artery reconstruction, should carotid artery resection be required for adequate tumor removal. When the preoperative evaluation indicates that adequate cerebral perfusion or collateral reserve will not be maintained with carotid artery occlusion, carotid artery reconstruction needs to accompany any resection of this vessel. Autogenous saphenous vein remains the graft conduit of choice, but prosthetic materials may be used. Graft patency and healing require appropriate concomitant soft-tissue coverage of any overlying mucosal or cutaneous defects.

Does arterial inflow failure cause distal vein graft thrombosis? A prospective analysis of 450 infrainguinal vascular reconstructions.

Classically, inadequate arterial inflow, diseased runoff, and poor bypass conduit quality have all been cited as causes of infrainguinal vein graft failure. To examine the role of arterial inflow failure as a specific cause of vein graft thrombosis, we prospectively analyzed 450 consecutive infrainguinal vascular reconstructions by means of a strict duplex scan surveillance protocol at three teaching institutions from 1986 to 1993. Sixteen incidences of arterial inflow failure (11 occlusions and five high-grade stenoses) above previously placed infrainguinal vein grafts were identified in 14 patients and confirmed by arteriography. Despite these inflow failures, all 14 autogenous vein infrainguinal reconstructions remained patent on arteriography. These inflow failures were observed from 2 to 72 months (mean 16 months) after infrainguinal reconstruction. Immediate successful inflow repair was performed in 13 of the 16 failures. Conversely, among 450 grafts followed, 37 acute graft occlusions occurred-all with arteriographically or noninvasively documented normal inflow. Thus no graft in the series has yet failed as a result of inflow occlusion (mean follow-up 22 months; range 1 to 78 months). We thus conclude that properly constructed infrainguinal saphenous vein bypass grafts with an intact endothelium often remain patent through low-flow collateral vessels despite total arterial inflow occlusion. These data thus challenge the premise that arterial inflow disease is a major cause of infrainguinal vein bypass occlusion.

Iliac vein compression syndrome: an unusual cause of varicocele.

Iliac vein compression syndrome is the phenomenon of nonthrombotic iliac vein obstruction caused by compression of left iliac vein between the right iliac artery and fifth lumbar vertebra. Affected patients usually present with unilateral leg edema. The condition is most often seen in women, in whom it may also be a cause of vulvar varicosities. Presented here is a case of idiopathic iliac vein obstruction associated with an ipsilateral varicocele in a young man. This varicocele was caused by multiple collateral venous channels and was resistant to surgical high ligation. This case illustrates an unusual cause of varicocele formation and an anatomic reason for failure of standard surgical therapy.

The role of the deep femoral artery as an inflow site for infrainguinal revascularization.

PURPOSE: Although the deep femoral artery (DFA) is well acknowledged as an outflow vessel for inflow reconstruction, data are lacking concerning the suitability of the DFA as an inflow site for distal bypass. METHODS: From 1986 to 1992 we performed 268 consecutive infrainguinal reversed vein bypasses, of which 56 (21%) originated from the middle or distal DFA. The indications for DFA-origin grafts included inadequate vein length, need for concomitant extended profundaplasty, and avoidance of groin scarring from previous reconstruction or infection. The surgical approach to the DFA (standard, posteromedial, or lateral) was tailored to the patient. All grafts were monitored with serial duplex scanning surveillance. RESULTS: Primary and secondary patency rates of DFA origin grafts were 78% and 96% at 3 years. These patency rates were no different from those grafts originating from the common femoral artery (66%; 89%), the superficial femoral artery (69%; 87%), or the popliteal artery (66%; 87%). Hemodynamic failure was detected in seven DFA-origin grafts, but only one resulted from disease in the common femoral artery or DFA proximal to the origin of the vein graft. CONCLUSIONS: Direct lateral and posteromedial approaches to the DFA were used extensively in repeat operative situations, avoiding dissection in a scarred groin and shortening the length of vein required to perform an autogenous bypass. We conclude that in appropriately selected patients, the DFA origin technique increases the versatility of lower extremity vein bypass grafting without sacrificing durability.

Combined coronary artery bypass and abdominal aortic aneurysmectomy: appropriate management in selected cases.

Patients with aortic aneurysms frequently have concomitant coronary artery disease, which carries the potential for significantly increased perioperative morbidity. Most cases of severe surgically correctable coronary artery disease can and should be treated by a separate operation before aneurysmectomy to lower operative cardiac morbidity and enhance long-term survival. Infrequently, a patient can have both unstable coronary disease and a large symptomatic aortic aneurysm. In this situation, a single procedure combining coronary artery bypass followed by aneurysmectomy, as illustrated by this case report, is a reasonable option and should be considered in the cases of carefully selected patients.

The "blue-toe" syndrome as a harbinger of impending infrainguinal vein graft failure: a report of three cases.

Spontaneous "blue-toe" syndrome classically results from distal lower extremity microembolization of intraluminal atheromatous debris from a proximal source to the digital end arteries. During a 6-year period, 274 consecutive infrainguinal reversed vein arterial reconstructions were performed; in three patients (1.1% incidence), atypical distal microembolization originating from focal preocclusive intraluminal vein graft stenoses was identified. Sudden, spontaneous onset of ipsilateral blue-toe syndrome occurred at intervals of 4 to 11 months. Subsequent duplex scans and arteriography demonstrated patent grafts with high-grade, hemodynamically significant focal proximal short-segment sclerotic vein graft stenosis (n = 1) and midgraft valvular weblike stenoses (n = 2) with luminal irregularity. No other associated tandem lesions in the proximal or distal arterial tree were noted that would account for the microembolic phenomenon. The stenotic vein segments were excised with interposition vein graft replacement (n = 1) or with primary end-to-end reanastomoses (n = 2), resulting in complete resolution of the distal microembolic events without need for amputation. Histologic examination of these graft lesions demonstrated significant focal myointimal hyperplasia with adherent platelet aggregates and organized thrombus. The clinical presentation of distal lower extremity cutaneous digital ischemia consistent with microembolization developing ipsilateral to a previously placed vein conduit arterial bypass may signify a "failing" graft with a source from a preocclusive lesion. This finding should prompt aggressive evaluation and immediate revision to maintain assisted primary graft patency and prevention of tissue loss.

Revision of the failing vein graft: outcome of secondary operations.

Infrainguinal vein bypass continues to be widely accepted as providing effective palliation for disabling claudication and limb salvage in patients with arterial insufficiency of the lower extremity. The development of lesions that may threaten vein graft patency are presently an inevitable consequence of arterial reconstruction in the atherosclerotic patient. However, long-term patency has been sustained by detection and intervention for inflow, outflow, or intrinsic graft lesions. The excellent secondary (assisted primary) patency rates achieved for both reversed and in situ vein grafts affirm the importance of a noninvasive surveillance protocol and a low threshold for reintervention before actual graft failure.

A reevaluation of intraarterial thrombolytic therapy for acute lower extremity ischemia.

PURPOSE: This study was performed to clarify the role of intraarterial thrombolytic therapy (IATT) in the management of acute lower extremity ischemia. METHODS: A retrospective review of 77 patients undergoing 84 courses of high-dose regional urokinase IATT from July 1981 to June 1991 was performed. The group included patients with acute thrombosis of lower extremity bypass grafts (n = 48) or native arteries (n = 36), presenting with ischemic but viable limbs, minimal or no motor dysfunction, and an absence of muscle rigor or compartment syndrome. The data were then examined individually by site of thrombosis to evaluate patient selection for IATT. RESULTS: Complete lysis, complications (either distal thromboembolism or bleeding), and early limb loss occurred in 59.5%, 11%, and 6% of infusions, respectively. IATT precluded the need for operative intervention in 49% of acutely ischemic limbs. When surgery was required, successful IATT precisely localized responsible lesions and reduced the magnitude of operation. A subset of 13 patients were identified in whom either no intrinsic abnormality or poor runoff were evident after lysis and were treated with anticoagulation alone. CONCLUSIONS: These data show IATT to be especially suitable for thrombosis of native iliac or femoropopliteal arteries and infrainguinal vein grafts. IATT serves primarily as an adjunct in management of acute lower extremity ischemia. After successful IATT, subsequent therapy can be tailored to the anatomic cause of thrombosis.