Chronic mesenteric ischemia: clinical practice guidelines from the Society for Vascular Surgery

Chronic mesenteric ischemia (CMI) results from the inability to achieve adequate postprandial intestinal blood flow, usually from atherosclerotic occlusive disease at the origins of the mesenteric vessels. Patients typically present with postprandial pain, food fear, and weight loss, although they can present with acute mesenteric ischemia and bowel infarction. The diagnosis requires a combination of the appropriate clinical symptoms and significant mesenteric artery occlusive disease, although it is often delayed given the spectrum of gastrointestinal disorders associated with abdominal pain and weight loss. The treatment goals include relieving the presenting symptoms, preventing progression to acute mesenteric ischemia, and improving overall quality of life. These practice guidelines were developed to provide the best possible evidence for the diagnosis and treatment of patients with CMI from atherosclerosis. The Society for Vascular Surgery established a committee composed of vascular surgeons and individuals experienced with evidence-based reviews. The committee focused on six specific areas, including the diagnostic evaluation, indications for treatment, choice of treatment, perioperative evaluation, endovascular/open revascularization, and surveillance/remediation. A formal systematic review was performed by the evidence team to identify the optimal technique for revascularization. Specific practice recommendations were developed using the Grading of Recommendations Assessment, Development, and Evaluation system based on review of literature, the strength of the data, and consensus. Patients with symptoms consistent with CMI should undergo an expedited workup, including a computed tomography arteriogram, to exclude other potential causes. The diagnosis is supported by significant arterial occlusive disease in the mesenteric vessels, particularly the superior mesenteric artery. Treatment requires revascularization with the primary target being the superior mesenteric artery. Endovascular revascularization with a balloon-expandable covered intraluminal stent is the recommended initial treatment with open repair reserved for select younger patients and those who are not endovascular candidates. Long-term follow-up and surveillance are recommended after revascularization and for asymptomatic patients with severe mesenteric occlusive disease. Patient with recurrent symptoms after revascularization owing to recurrent stenoses should be treated with an endovascular-first approach, similar to the de novo lesion. These practice guidelines were developed based on the best available evidence. They should help to optimize the care of patients with CMI. Multiple areas for future research were identified.

Contribution of the Southern Association for Vascular Surgery to the scientific literature.

The Southern Association for Vascular Surgery (SAVS) has played a significant role in the development and evolution of vascular surgery. This study was designed to document the contribution to the scientific literature and to highlight the important publications from the annual meetings of the SAVS on its 25th anniversary. A total of 413 (73%) of the 569 "free papers" presented at the SAVS Annual Meeting were published in journals that are identified in MEDLINE, and most (71%) were published in the Journal of Vascular Surgery. Carotid/cerebrovascular disease, leg ischemia, and basic considerations were the most common subject matters overall, although there has been a recent decrease in the percentage of articles about basic considerations and aortic aneurysms while there has been an increase in those about endovascular therapy, vascular laboratory/imaging, and visceral/renal artery disease. The 413 papers were cited a mean of 18 +/- 20 (+/- SD) times (range 0-143) with 32 papers cited more than 39 times and 17 papers cited more than 59 times. A panel of three reviewers identified 42 significant articles, among which 8 were considered seminal by 2 of the 3 reviewers. The papers presented at the annual meeting of the SAVS have made a significant contribution to the scientific literature in terms of both quantity and quality. These efforts have laid the foundation for the next quarter century and have raised the level of expectation.

The outcome in the United States after thoracoabdominal aortic aneurysm repair, renal artery bypass, and mesenteric revascularization.

OBJECTIVES: The purpose of this study was to determine outcome and identify predictors of death after thoracoabdominal aortic aneurysm (TAA) repair, renal artery bypass (RAB), and revascularization for chronic mesenteric ischemia (CMI). PATIENTS AND METHODS: In this retrospective analysis, data were obtained from the Nationwide Inpatient Sample, a 20% all-payer stratified sample of hospitals in the United States during 1993 to 1997. Patients were identified by the presence of a diagnostic or procedure code from the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). The main outcomes we examined were death, ICD-9-CM -based complications, length of stay, hospital charges, and disposition. A multivariate model was constructed to predict death. RESULTS: A total of 2934 patients were identified (TAA, 540; RAB, 2058; CMI, 336) in the database. The mean age was comparable (TAA, 69 +/- 9 years; RAB, 66 +/- 12 years; CMI, 66 +/- 11 years), but the breakdown between the sexes varied by procedure (male: TAA, 53%; RAB, 55%; CMI, 24%). The mortality rate (TAA, 20.3%; RAB, 7.1%; CMI, 14.7%), complication rate (TAA, 62.2%; RAB, 37.4%; CMI, 44.6%), and the percentage of patients discharged to another institution (TAA, 21.2%; RAB, 9.3%; CMI, 12.0%) were clinically significant for all procedures. The mortality rate for RAB was greater when performed concomitant with an aortic reconstruction (4.4% vs 8.3%). All three procedures were resource intensive as reflected by the median length of stay (TAA, 14 days; RAB, 9 days; CMI, 14 days) and median hospital charges (TAA, $64,493; RAB, $36,830; CMI, $47,390). The multivariate model identified several variables for each procedure that had an impact on the predicted mortality rate (TAA, 14%-76%; RAB, < 1%-46%; CMI, < 2%-87%). CONCLUSIONS: The operative mortality rates across the United States for patients undergoing TAA repair and RAB are greater than commonly reported in the literature and mandate reexamining the treatment strategies for these complex vascular problems.

Limb salvage surgery with vascular reconstruction.

Vascular reconstruction and limb salvage surgery has been the authors' preferred approach when malignancy involves major vessels of the extremities. Treatment of 16 patients involved resection, with vascular grafting in 14 patients and rotationplasty in two patients. The major vessels were surrounded by tumor in six patients, nearly encased in three patients, invaded by tumor in four patients, and widely contaminated by intralesional surgery in three patients. The tumor stage included one Stage IB, 12 Stage IIB, two Stage IIIB sarcomas, and one multiply recurrent carcinoma. The largest average tumor dimension was 9.5 cm, and the length of grafting was 14 cm. Major nerves were sacrificed in eight (50%) patients, flaps or muscle transfers were done in seven (44%), chemotherapy was administered in nine (56%), radiation therapy was used in four (25%), and pulmonary metastasectomy was done in two (12%). At a mean followup of 56 months, 50% (eight of 16) of patients were alive without disease. Local recurrence was 12% (two of 16 patients), and infection was 12% (two of 16 patients). Limb salvage was achieved in 88% (14 of 16 patients), and functional status was judged good or excellent in 81% (13 of 16 patients). The complication rate observed in this subset of patients is significant, yet local control and the incidence of major complications was acceptable. Results observed from this series and data gathered from the literature clearly indicate that patients can avoid amputation, despite malignant involvement of major vessels to their extremities.

External-beam radiation therapy for improved dialysis access patency: feasibility and early safety.

Rectenwald, J. E., Pretus, H. A., Seeger, J. M., Huber, T. S., Mendenhall, N. P., Zlotecki, R. A., Palta, J. R., Li, Z. F., Hook, S. Y., Sarac, T. P., Welborn, M. B., Klingman, N. V., Abouhamze, Z. S. and Ozaki, C. K. External-Beam Radiation Therapy for Improved Dialysis Access Patency: Feasibility and Early Safety. Radiat. Res. 156, 53-60 (2001).Prosthetic dialysis access grafts fail secondary to neointimal hyperplasia at the venous anastomosis. We hypothesized that postoperative single-fraction external-beam radiation therapy to the venous anastomosis of hemodialysis grafts can be used safely in an effort to improve access patency. Dogs (n = 8) underwent placement of expanded polytetrafluoroethylene grafts from the right carotid artery to the left jugular vein. Five dogs received single-fraction external-beam photon irradiation (8 Gy) to the venous anastomosis after surgery. Controls were not irradiated. Shunt angiograms were completed 3 and 6 months postoperatively. Anastomoses, mid-graft, and the surrounding tissues were analyzed. Immunohistochemistry for smooth muscle cell alpha-actin, proliferating cellular nuclear antigen (PCNA), and apoptosis was performed. Incisions healed well, though all animals developed wound seromas. One control suffered graft thrombosis 4 months postoperatively. Angiography/histology confirmed severe neointimal hyperplasia at the venous anastomosis. The remaining seven dogs developed similar amounts of neointimal hyperplasia. PCNA studies showed no accelerated fibroproliferative response at irradiated anastomoses compared to controls. Skin incisions and soft tissues over irradiated anastomoses revealed no radiation-induced changes or increase in apoptosis. Thus we conclude that postoperative single-fraction external-beam irradiation of the venous anastomosis of a prosthetic arteriovenous graft that mimics the situation in humans is feasible and safe with regard to early wound healing.

Experience in the United States with intact abdominal aortic aneurysm repair.

OBJECTIVES: The purpose of this study was to determine the current outcome in the United States and to identify predictors of mortality and "bad outcome" after open, intact abdominal aortic aneurysm (AAA) repair. METHODS: In a retrospective analysis, data were obtained from the Nationwide Inpatient Sample during 1994-1996. The Nationwide Inpatient Sample is a 20% all-payer stratified sample of nonfederal United States hospitals. Patients older than 49 years were identified by the presence of primary diagnostic (441.4-intact AAA) and procedure (38.44-resection of abdominal aorta with replacement) codes of the International Classification of Diseases, Ninth Revision (ICD-9 ). In-hospital mortality rate, discharge disposition, bad outcome (death or discharge to an institution), complications (ICD-9 postoperative codes), length of stay, and charges were determined. The mortality rate and bad outcome were analyzed by the use of patient demographics (age, sex, race), patient comorbidities (ICD-9 diagnostic codes), calendar year, and hospital characteristics (size, location, teaching status) with univariate and multivariate analyses. RESULTS: We identified 16,450 intact AAAs repairs during the study years. The mean patient age was 72 +/- 7 (+/- SD) years, and most patients were male (79.7%) and white (94.6%). Most repairs were performed at large (67.3%), urban (92.5%), and nonteaching (66.7%) institutions. The in-hospital mortality rate was 4.2%, the overall complication rate was 32.4%, and 91.2% of patients were discharged home, whereas the bad outcome rate was 12.6%. The median length of stay was 8 days (mean, 10.0 +/- 8.1), and median hospital charges were $28,052 (mean, $35,681 +/- $33,006) in 1996 dollars. Multivariate analysis showed that the mortality rate (P <.05) increased with age (70-79 years, 1.8 odds ratio [OR] [95% CI, 1.4-2.3], > 79 years, 3.8 OR [95% CI, 2.9-4.9]), sex (female, 1.6 OR [95% CI, 1.3-1.9]), cerebral vascular occlusive disease (1.8 OR [95% CI, 1.3-2.5]), preoperative renal insufficiency (9.5 OR [95% CI, 7.7-11.7]), and more than three comorbidities (11.2 OR [95% CI, 3.6-35.4]). Multivariate analysis also showed that bad outcome was associated with the same variables in addition to hospital size (small/medium), year of procedure (1996), chronic obstructive pulmonary disease, and two to three comorbidities. CONCLUSIONS: Outcome after open repair of intact AAA across the United States is quite good. Older, sicker patients may benefit from nonoperative treatment or the potentially lower risk endovascular approaches.

Direct evidence for cytokine involvement in neointimal hyperplasia.

BACKGROUND: Tumor necrosis factor-alpha (TNF-alpha) and interleukin 1 (IL-1) are proximal inflammatory cytokines that stimulate expression of adhesion molecules and induce synthesis of other proinflammatory cytokines. In addition, TNF-alpha and IL-1 influence vascular smooth muscle cell migration and proliferation in vitro. In view of the inflammatory nature of neointimal hyperplasia (NIH), we tested the hypothesis that endogenous TNF-alpha and IL-1 modulate low shear stress-induced NIH. METHODS AND RESULTS: Mice underwent unilateral common carotid artery (CCA) ligation. Low shear stress in the patent ligated CCA has previously been shown to result in remodeling and NIH. Reverse transcriptase-polymerase chain reaction for TNF-alpha and IL-1alpha mRNA demonstrated both TNF-alpha and IL-1alpha mRNA in ligated CCAs, whereas normal and sham-operated CCAs had none. Mice lacking functional TNF-alpha (TNF-/-) developed 14-fold less neointimal area than WT controls (P:<0.05). p80 IL-1 type I receptor knockout (IL-1RI-/-) mice tended to develop less (7-fold, P:>0.05) neointimal area than WT controls. Furthermore, no IL-1alpha mRNA expression was detected in CCAs from TNF-/- mice; however, TNF-alpha mRNA expression was found in the IL-1RI-/- mice. Mice that overexpress membrane-bound TNF-alpha but produce no soluble TNF-alpha display an accentuated fibroproliferative response to low shear stress (P:<0.05). CONCLUSIONS: These results directly demonstrate that TNF-alpha and IL-1 modulate NIH induced by low shear stress. NIH can proceed by way of soluble TNF-alpha-independent mechanisms. Specific anti-TNF-alpha and anti-IL-1 therapies may lessen NIH.

The relationship between visceral ischemia, proinflammatory cytokines, and organ injury in patients undergoing thoracoabdominal aortic aneurysm repair.

OBJECTIVES: Plasma proinflammatory, anti-inflammatory cytokine, and soluble tumor necrosis factor (TNF) receptor concentrations were examined in hospitalized patients after abdominal and thoracoabdominal aortic aneurysm (TAAA) repair, with and without left atrial femoral bypass. Changes in plasma cytokine concentrations were related to the duration of visceral ischemia and the frequency rate of postoperative, single, or multiple system organ dysfunction (MSOD). DESIGN: Prospective, observational study. SETTING: Two academic referral centers in the United States and The Netherlands. PATIENTS: We included 16 patients undergoing TAAA repair without left atrial femoral bypass, 12 patients undergoing TAAA repair with left atrial femoral bypass, and nine patients undergoing infrarenal aortic aneurysm repair. MEASUREMENTS AND MAIN RESULTS: Timed, arterial blood sampling for proinflammatory and anti-inflammatory cytokine and soluble TNF receptor concentrations (p55 and p75), and prospective assessment of postoperative single and MSOD. Plasma appearance of TNF-alpha, interleukin (IL)-6, IL-8, and IL-10 peaked 1 to 4 hrs after TAAA repair, and concentrations were significantly elevated compared with infrarenal abdominal aortic aneurysm repair (p < .05). Left atrial femoral bypass significantly reduced the duration of visceral ischemia (p < .05) and the systemic TNF-alpha, p75, and IL-10 responses (p < .05). Plasma TNF-alpha concentrations >150 pg/mL were more common in patients with extended visceral ischemia times (>40 mins). Additionally, patients with early peak TNF-alpha concentrations >150 pg/mL and IL-6 levels >1,000 pg/mL developed MSOD more frequently than patients without these elevated plasma cytokine levels (both p < .05). CONCLUSIONS: Thoracoabdominal aortic aneurysm repair results in the increased plasma appearance of TNF-alpha, IL-6, IL-8, IL-10, and shed TNF receptors. The frequency and magnitude of postoperative organ dysfunction after TAAA repair is associated with an increased concentration of the cytokines, TNF-alpha, and IL-6 and the increased plasma levels of these cytokines appear to require extended visceral ischemia times.

Laparotomy prevents lethal endotoxemia in a murine sequential insult model by an IL-10-dependent mechanism.

Multiple organ dysfunction and death are common sequelae after mesenteric ischemia-reperfusion injury as seen with mesenteric revascularization and thoracoabdominal aortic aneurysm repair. A second insult such as bacterial pneumonia occurring subsequent to the ischemia-reperfusion injury may contribute to these untoward effects. We hypothesized the sequential visceral/lower torso ischemia-reperfusion and endotoxemia in a murine model would increase the magnitude of the proinflammatory cytokine response and decrease survival. C57BL/6 mice underwent 20 min of supraceliac occlusion (IR), sham laparotomy (LAP), or no initial insult (CTRL) followed by intraperitoneal injection of a lethal dose of endotoxin (LPS [lipopolysaccharide 50 mg/kg] or saline vehicle at 24 h. Serum cytokine levels were measured by enzyme-linked immunosorbent assay (IL-10, IL-6) or WEHI bioassay [tumor necrosis factor (TNF)], and survival was determined at 5 days. The role of IL-10 on the TNF response and survival was examined in a subset of mice given mouse anti IL-10 IgM (25 mg/kg intraperitoneally) 2 h prior to the initial insult. Survival after LPS was significantly different (P < 0.05) among the treatment groups (IR, 64%; LAP, 55%; CTRL, 11%) and appeared to trend directly with the magnitude of the initial operation. The serum IL-10 levels in the IR and LAP groups were significantly increased 4 h after the initial insult and remained elevated at 24 h. Peak serum TNF levels after LPS were significantly lower in the IR and LAP groups. Administration of anti IL-10 IgM resulted in uniform mortality and a significant increase in the peak TNF levels after LPS administration for all initial treatment groups. Endogenous production of IL-10 following laparotomy down-regulates the TNF response and improves survival after endotoxemia.

Long-term outcome after treatment of aortic graft infection with staged extra-anatomic bypass grafting and aortic graft removal.

OBJECTIVE: The purpose of this study was to determine long-term outcome in patients with infected prosthetic aortic grafts who were treated with extra-anatomic bypass grafting and aortic graft removal. METHODS: Between January 1989 and July 1999, 36 patients were treated for aortic graft infection with extra-anatomic bypass grafting and aortic graft removal. Extra-anatomic bypass graft types were axillofemoral femoral (5), axillofemoral (26; bilateral in 20), axillopopliteal (3; bilateral in 1) and axillofemoral/axillopopliteal (2). The mean follow-up was 32.3 +/- 4. 8 months. RESULTS: Four patients (11%) died in the postoperative period, and two patients died during follow-up as a direct consequence of extra-anatomic bypass grafting and aortic graft removal (one died 7 months after extra-anatomic bypass graft failure, one died 36 months after aortic stump disruption). One additional patient died 72 months after failure of a subsequent aortic reconstruction, so that the overall treatment-related mortality was 19%, whereas overall survival by means of life table analysis was 56% at 5 years. No amputations were required in the postoperative period, but four patients (11%) required amputation during follow-up. Twelve patients (35%) had extra-anatomic bypass graft failure during follow-up, and six patients underwent secondary aortic reconstruction (thoracobifemoral [2], iliofemoral [2], femorofemoral [2]). However, with the exclusion of patients undergoing axillopopliteal grafts (primary patency 0% at 7 months), only seven patients (25%) had extra-anatomic bypass graft failure, and only two patients required amputation (one after extra-anatomic bypass graft removal for infection, one after failure of a secondary aortic reconstruction). Furthermore, primary and secondary patency rates by means of life table analysis were 75% and 100% at 41 months for axillofemoral femoral grafts and 64% and 100% at 60 months for axillofemoral grafts. Only one patient required extra-anatomic bypass graft removal for recurrent infection, and only one late aortic stump disruption occurred. CONCLUSIONS: Staged extra-anatomic bypass grafting (with axillofemoral bypass graft) and aortic graft removal for treatment of aortic graft infection are associated with acceptable early and long-term outcomes and should remain a primary approach in selected patients with this grave problem.

Anticytokine therapies for acute inflammation and the systemic inflammatory response syndrome: IL-10 and ischemia/reperfusion injury as a new paradigm.

The results of recent anticytokine trials for sepsis syndrome have been disappointing. Several Phase II and Phase III clinical trials have shown a modest benefit in various subsets of patients; however, there has been no reported benefit in the primary endpoint of 28-day all-cause mortality. The failure of these trials is clearly multifactorial, and causes include the overall complexity of the inflammatory response, heterogeneity of the patient populations, absence of a hypercytokine response at the time of drug treatment, and the relatively short half-life of the administered drugs. The failure of anticytokine therapies may represent inadequate application of the treatment modality rather than any inherent weakness of the treatment itself. We have recently initiated a Phase I clinical trial examining the role of the anti-inflammatory cytokine IL-10 during surgical repair of a thoracoabdominal aortic aneurysm. This study may overcome some of the-design limitations of previous anticytokine trials in sepsis, and serve as a paradigm for future anticytokine therapy trials. Although the incidence of thoracoabdominal aortic aneurysms is relatively low, the patient population is homogeneous and the surgical injury associated with its repair reproducible. Additionally, postoperative mortality and morbidity rates are significant. Most importantly, the operative repair is associated with an obligatory visceral ischemia and reperfusion injury that appears to be associated with a proinflammatory cytokine response and postoperative organ dysfunction. IL-10 is a pleuripotent anti-inflammatory cytokine that both inhibits TNFalpha and IL-1 synthesis, and antagonizes their actions through upregulation of cytokine antagonists. Furthermore, IL-10 administration has been associated with only minimal adverse side effects during Phase I and Phase II trials.

Use of superficial femoral vein for hemodialysis arteriovenous access.

Maintaining hemodialysis access in the expanding number of patients with end-stage renal disease is a difficult and challenging problem. Published guidelines outline the initial recommendations for hemodialysis access; however, there is little consensus about the most appropriate options for the subset of patients with repeated access failures and/or unsuitable veins. Two case reports are presented describing the use of composite saphenous-superficial femoral vein autogenous accesses placed in the upper and lower extremities. The function of the autogenous accesses appeared to be similar to a mature arteriovenous fistula in the short-term, although further longitudinal studies are required. The superficial femoral vein may be a useful hemodialysis access conduit for patients with limited access options.

Financial impact of tertiary care in an academic medical center.

OBJECTIVE: To analyze the financial impact of three complex vascular surgical procedures to both an academic hospital and a department of surgery and to examine the potential impact of decreased reimbursements. SUMMARY BACKGROUND DATA: The cost of providing tertiary care has been implicated as one potential cause of the financial difficulties affecting academic medical centers. METHODS: Patients undergoing revascularization for chronic mesenteric ischemia, elective thoracoabdominal aortic aneurysm repair, and treatment of infected aortic grafts at the University of Florida were compared with those undergoing elective infrarenal aortic reconstruction and carotid endarterectomy. Hospital costs and profit summaries were obtained from the Clinical Resource Management Office. Departmental costs and profit summary were estimated based on the procedural relative value units (RVUs), the average clinical cost per RVU ($33.12), surgeon charges, and the collection rate for the vascular surgery division (30.2%) obtained from the Faculty Group Practice. Surgeon work effort was analyzed using the procedural work RVUs and the estimated total care time. The analyses were performed for all payors and the subset of Medicare patients, and the potential impact of a 15% reduction in hospital and physician reimbursement was analyzed. RESULTS: Net hospital income was positive for all but one of the tertiary care procedures, but net losses were sustained by the hospital for the mesenteric ischemia and infected aortic graft groups among the Medicare patients. In contrast, the estimated reimbursement to the department of surgery for all payors was insufficient to offset the clinical cost of providing the RVUs for all procedures, and the estimated losses were greater for the Medicare patients alone. The surgeon work effort was dramatically higher for the tertiary care procedures, whereas the reimbursement per work effort was lower. A 15% reduction in reimbursement would result in an estimated net loss to the hospital for each of the tertiary care procedures and would exacerbate the estimated losses to the department. CONCLUSIONS: Caring for complex surgical problems is currently profitable to an academic hospital but is associated with marginal losses for a department of surgery. Economic forces resulting from further decreases in hospital and physician reimbursement may limit access to academic medical centers and surgeons for patients with complex surgical problems and may compromise the overall academic mission.

Surgical decision making for carotid endarterectomy and contemporary magnetic resonance angiography.

BACKGROUND: Benefit from carotid endarterectomy (CEA) centers on patient selection and percent stenosis as determined by cerebral angiography. However, angiography remains expensive and poses risks. Validated carotid duplex ultrasonography has proven to be an accurate tool for selecting patients for CEA. However, the role of another noninvasive test-magnetic resonance angiography (MRA)-remains uncertain. Because of recent advances in MRA hardware and software, we hypothesized that clinically appropriate patients could be accurately selected for CEA based on MRA alone. METHODS: Fifty-four carotid arteries in 29 patients (with and without symptoms) underwent both three-dimensional time-of-flight MRA (1.5 Tesla) with multiple overlapping thin slab acquisition and biplanar intra-arterial digital subtraction angiography. All patients undergoing both tests over a 24-month period were included. The majority of these patients did not undergo carotid duplex ultrasound owing to the clinical practice of the hospital's neurosurgery service. Staff radiologists interpreted each study. The accuracy of patient selection based on MRA was calculated using angiography as the standard (NASCET method). Since operative thresholds vary depending on clinical history, we considered four commonly used ranges of percent stenosis for CEA. RESULTS: Patient selection accuracy of MRA alone was low, but increased as percent stenosis increased. Out of 10 occluded arteries by angiography, 5 were interpreted as patent with stenosis (70% to 99%) by MRA. One patent artery was misread as occluded on MRA. CONCLUSION: Reliance solely on contemporary MRA for surgical decision making cannot be justified in view of low accuracy, which leads to high rates of error in patient selection for CEA.

Impact of race on the treatment for peripheral arterial occlusive disease.

PURPOSE: The purpose of this study was to determine the impact of race on the treatment of peripheral artery occlusive disease (PAOD) and to examine the role of access to care and disease distribution on the observed racial disparity. METHODS: The study was performed as a retrospective analysis of hospital discharge abstracts from 1992 to 1995 in 202 non-federal, acute-care hospitals in the state of Florida. The subjects were patients older than 44 years of age who underwent major lower extremity amputation or revascularization (bypass grafting or angioplasty) for PAOD. The main outcome measures were incidence of intervention, incidence per demographic group, multivariate predictors of amputation versus revascularization, multivariate predictors of amputation versus revascularization among those patients with access to sophisticated care (hospital with arteriographic capabilities), and multivariate predictors of surgical bypass graft type (aortoiliac vs infrainguinal). RESULTS: A total of 51,819 procedures (9.1 per 10,000 population) were performed for PAOD during the study period and included 15,579 major lower extremity amputations (30.1%) and 36,240 revascularizations (69.9%). Although the incidence of a procedure for PAOD was comparable between African Americans and whites (9.0 vs 9.6 per 10, 000 demographic group), the incidence of amputation (5.0 vs 2.5 per 10,000 demographic group) was higher and the incidence of revascularization (4.0 vs 7.1 per 10,000 demographic group) was lower among African Americans. Furthermore, multivariate analysis results showed that African Americans (odds ratio, 3.79; 95% confidence interval [CI], 3.34 to 4.30) were significantly more likely than whites to undergo amputation as opposed to revascularization. The secondary multivariate analyses results revealed that African Americans (odds ratio, 2.29; 95% CI, 1.58 to 3. 33) were more likely to undergo amputation among those patients (n = 9193) who underwent arteriography during the procedural admission and to undergo infrainguinal bypass grafting (odds ratio, 2.00; 95% CI, 1.48 to 2.71) among those patients (n = 27,796) who underwent surgical bypass grafting. CONCLUSION: There is a marked racial disparity in the treatment of patients with PAOD that may be caused in part by differences in the severity of disease or disease distribution.

Potential predictors of outcome in patients with tissue loss who undergo infrainguinal vein bypass grafting.

PURPOSE: Aggressive attempts at limb salvage in patients with ischemic tissue loss are justified by favorable initial results in most patients. The identification of patients whose conditions will not benefit from attempted revascularization remains difficult. METHODS: This study was designed as a retrospective review of prospectively collected clinical data. The subjects were 210 consecutive patients who underwent infrainguinal vein bypass grafting for ischemic tissue loss in the setting of an academic medical center. Bypass grafting was to the popliteal artery in 56 patients, to the infrapopliteal arteries in 131 patients, and to the pedal arteries in 23 patients. The follow-up examination was complete in 209 of 210 patients. One hundred twenty-five patients underwent blinded review of duplex scan venous mapping and arteriography to determine simplified vein and run-off scores. The outcome measures were the influence of risk factors, venous conduit, and runoff on mortality, limb loss, and graft failure at the 6-month follow-up examination. RESULTS: One hundred seventy patients (81%) were alive and had limb salvage. Nineteen patients (9.1%) died, with need for a simultaneous inflow procedure and end-stage renal disease being most commonly associated with mortality. Thirty-three patients (15.8%) had undergone amputation: 18 after graft failure, and 15 for progressive tissue loss despite a patent graft. Amputation was significantly more common in patients with diabetes (P =.05) and with poor runoff scores (poor runoff, 44.4% vs good runoff, 7.4%; P <.01). Amputation despite a patent graft also correlated with runoff (poor runoff, 41.7% vs good runoff, 4.3%; P <.01). Twenty-five patients had graft failure without amputation, so that only 145 patients (69.4%) were alive, had limb salvage, and had a patent graft. Run-off score was the strongest predictor of outcome, with 70% of patients with poor run-off scores having death, amputation, or graft failure. CONCLUSION: Aggressive use of infrainguinal vein bypass grafting in patients with ischemic tissue loss results in a high rate of initial limb salvage but significant morbidity and mortality. Arteriographically determined runoff scores appear to potentially identify patients at high risk for a poor initial outcome and may provide a method of selecting patients for primary amputation.

Influence of patient characteristics and treatment options on outcome of patients with prosthetic aortic graft infection.

This study was undertaken to determine the influence of patient characteristics and treatment options on survival and limb loss after treatment of prosthetic aortic graft infection. Fifty-three patients treated for prosthetic aortic graft infection were reviewed. Twenty-three presented with groin infection, 12 with sepsis, 10 with aortoenteric fistula, 4 with limb ischemia, and 4 with pseudoaneurysm. Treatment included staged extraanatomic bypass (EAB) plus graft excision in 23 patients, simultaneous EAB and graft excision in 18, in situ graft replacement in 5, and local therapy only in 7. Axillofemoral bypass was done for revascularization in 53 limbs and axillopopliteal bypass in 16 limbs. The results of this study showed that morbidity and mortality of prosthetic aortic graft infection is influenced by the presentation and type of treatment of the infected graft. Staged axillofemoral bypass (when possible) plus graft excision appears to be associated with acceptable outcome (survival with limb salvage in 74%).

Attenuation of skeletal muscle ischemia/reperfusion injury by inhibition of tumor necrosis factor.

PURPOSE: Tumor necrosis factor alpha (TNF-alpha) has been shown to play a role in pulmonary injury after lower-extremity ischemia/reperfusion (I/R). However, its role in direct skeletal muscle injury is poorly understood. The hypothesis that endogenous TNF production contributes to skeletal muscle injury after hindlimb I/R in rats was tested. METHODS: Juvenile male Sprague-Dawley rats underwent 4 hours of bilateral hindlimb ischemia and 4 hours of reperfusion (IR) or sham operation (SHAM). A subset was treated with a soluble TNF receptor I construct (STNFRI, 10 mg/kg) 1 hour before ischemia (PRE) or at reperfusion (POST). Direct skeletal muscle injury (SMII) and muscle endothelial capillary permeability (MPI) were quantified by means of Tc99 pyrophosphate and I125 albumin uptake. Pulmonary neutrophil infiltration and hepatocellular injury were assessed by means of myeloperoxidase content (MPO) and aspartate aminotransferase (AST) concentrations, respectively. Serum TNF bioactivity was measured with the WEHI bioassay. RESULTS: Hindlimb I/R (IR vs SHAM) resulted in a significant (P <.05) increase in the SMII (0.52 +/- 0.06 vs 0.07 +/- 0.01) and MPI (0.35 +/-.04 vs 0.06 +/- 0.01). Pretreatment with STNFRI (PRE vs IR) significantly ameliorated both SMII (0.30 +/- 0.05 vs 0.52 +/- 0.06) and MPI (0.23 +/- 0.02 vs 0.35 +/- 0.04), whereas treatment at reperfusion (POST vs IR) had no effect. Hindlimb I/R (IR vs SHAM) resulted in both significant pulmonary neutrophil infiltration (MPO 16.4 +/- 1.06 U/g vs 11.3 +/- 1.4 U/g) and hepatocellular injury (AST 286 +/- 45 U/mL vs 108 +/- 30 U/mL), but neither was inhibited by pretreatment with STNFRI before ischemia. Detectable levels of TNF were measured during ischemia in a significantly higher percentage of the IR group compared with SHAM (9 of 12 vs 3 of 12), and the maximal TNF values were also significantly greater (51.1 +/- 12.6 pg/mL vs 5.5 +/- 2.9 pg/mL). No TNF was detected in any treatment group during reperfusion nor after administration of the STNFRI. CONCLUSION: Acute hindlimb IR initiates a systemic TNF response during the ischemic period that is partly responsible for the associated skeletal muscle injury.

Carotid surgery in octogenarians in Veterans Affairs medical centers.

The purpose of this study was to define outcomes after carotid surgery in octogenarians in the Veterans Affairs health care system. During fiscal years 1991-1994, 9152 patients in DRG 5 underwent extracranial vascular surgery procedures in Veterans Affairs medical centers. Those >/=80 years of age constituted 2.1% (n = 195) of such patients. In-hospital mortality rates were 1.03% (92/8957) in those <80 versus 3.08% (6/195) in those >/=80 years old (P = 0.018). Of those >/=80, 11.8% (23/195) had an ICD-9-CM-coded complication during hospitalization versus 11.2% of those <80 (1004/8957, NS). Surgical complications of the central nervous system (CNS) were present in 0.51% of octogenarians (1/195) and in 0.93% of those younger (83/8957, NS). Myocardial infarction (MI) occurred in 1.0% (2/195) of octogenarians and 0.74% (66/8967) of younger patients (NS). Patient Management Category software was used to define illness severity and resource intensity scale (RIS, a measure of resource utilization). Logistic regression analysis showed that age, illness severity, MI, and surgical complications of the CNS were associated with greater likelihood of mortality after extracranial vascular surgery. When the dichotomous variable "octogenarian status" was substituted for the continuous variable "age," in this model, there was no significant association of octogenarian status per se with mortality, though the association of illness severity, MI, and CNS complications with mortality persisted. Illness severity was greater for octogenarians (2.03 +/- 1.36) versus those younger (1.84 +/- 1.13, P < 0.05). RIS was 2.57 +/- 0.57 in octogenarians versus 2.47 +/- 0.48 for younger patients (P < 0.015). Length of stay (LOS) was a mean of 3.2 days longer for octogenarians (P < 0. 001). The risk of postoperative CNS complications was not higher in octogenarians. Mortality, resource utilization, and length of stay were, however, greater for octogenarians, but so was illness severity. Though mortality rates were greater for octogenarians in DRG 5, illness severity, MI, and postoperative CNS complications had greater impact on mortality after extracranial vascular surgery than octogenarian status per se.