Current Outcomes of Blunt Vertebral Artery Injuries.

BACKGROUND: There is no consensus on the treatment of blunt vertebral artery injuries, and studies are limited to small case series. We assessed the natural history and current management of these injuries. METHODS: We performed a retrospective study of a prospectively collected registry at a level I trauma center over a 5-year period. Additional information was gathered from patient charts and imaging review from electronic medical records. We analyzed demographics, mechanism of injury, Glasgow Coma Score, mortality, length of stay, associated injuries, Denver grading scale, neurological findings, level and laterality of injury, delay in diagnosis, treatment, and follow-up imaging. RESULTS: There were 13,080 trauma admissions during this time period yielding 141 patients with blunt vertebral artery injuries from 2013 to 2018 (1.1% incidence). Mean injury severity score (ISS) was 22 with a 30-day mortality of 14 (9.9%). An ISS of greater than 15 is associated with polytrauma and increased mortality. There were 112 (79.4%) associated cervical fractures. C6 and C7 were both equally the most common locations. There was one symptomatic injury manifesting as a cerebellar ischemic infarct. The degree of arterial injury was classified by the Denver grading scale. There were 61 (43.3%) instances of Denver grade I injuries, followed by grade IV at 36 (25.5%), grade II at 34 (24.1%), grade III at 8 (5.7%), and grade V at 1 (0.7%). The level of injury was recorded as follows: V2 = 67 (47.5%), V3 = 56 (39.7%), V1 = 48 (34%), V4 = 14 (9.9%). Medical therapy included aspirin in 93 patients (66%), 31 patients (22%) received systemic anticoagulation with heparin drip, and 2 patients (1%) were administered therapeutic Lovenox. A total of 15 patients (11%) received no medical treatment. There was one intervention in our series. Our only grade V injury was coil embolized. A total of 118 patients (84%) had follow-up imaging. Seventy-eight patients (96%) with grade I and grade II injuries did not worsen, and complete radiographic resolution was found in 50 patients (62%). Grade IV injuries persisted in 22 patients (75.9%). Median time to resolution for grade I and grade II injuries was 7 and 8 days, respectively. Most follow-up scans for grade I and II injuries occurred within 50 days. CONCLUSIONS: Posterior circulation stroke due to blunt vertebral artery injury is rare. In our experience, the natural course of blunt vertebral artery injury was benign and neither delay in medical treatment nor choice of antithrombotic had a significant impact on outcomes. In our series, only 3 (3.7%) grade I and II injuries worsened and were without any clinical sequelae. We suggest that routine serial imaging in grade I and II blunt vertebral injuries is not warranted.

Impact of sarcopenia on long-term mortality following endovascular aneurysm repair.

Sarcopenia, also known as a reduction of skeletal muscle mass, is a patient-specific risk factor for vascular and cancer patients. However, there are no data on abdominal aortic aneurysm (AAA) patients treated with endovascular aneurysm repair (EVAR) who have sarcopenia. To determine the impact of sarcopenia on mortality following EVAR, we retrospectively reviewed 200 patients treated with EVAR by estimating muscle mass on abdominal computed tomography (CT) scans. Mortality was analyzed according to its presence (n=25) or absence (n=175). Sarcopenia was more common in women than men (32.0% vs 9.7%; p=0.005). Patients with sarcopenia had an increased risk of mortality compared to those without (76% vs 48%; p=0.016). Of note, the overall mortality rate was 51% with a median follow up of 8.4 years (interquartile range, 5.3-11.7). In conclusion, the presence of sarcopenia on a CT scan is an important predictor of long-term mortality in patients treated for AAA with EVAR. Pending further study, these data suggest that sarcopenia may aid in pre-procedural long-term survival assessment of patients undergoing EVAR.

Influence of Clinically Relevant Mechanical Forces on Vascular Smooth Muscle Cells Under Chronic High Glucose: An In Vitro Dynamic Disease Model.

BACKGROUND: In this study, we subjected vascular smooth muscle cells (VSMC) to acute and chronic high glucose conditions under physiologically relevant levels of cyclic strain and low wall shear forces to compare phenotypic modulation and thus conceptualize a dynamic-disease test model which captures cellular response more accurately in comparison with static cultures. METHODS: P2-P6 rat aortic smooth muscle cells were seeded on type I collagen-coated silicone membranes and subjected to 0-7% cyclic strain at 1 Hz and 0.3 dynes/cm(2) shear stress from flow for 24 hr under acute (25 mM d-glucose, 84 hr) and chronic high glucose conditions (25 mM d-glucose, 3-4 weeks). Samples were analyzed for cell proliferation, percent apoptosis, cellular hypertrophy, and expression levels of smooth muscle contractile state-associated markers with 0.05 level of significance. RESULTS: Concomitant application of cyclic strain and flow shear resulted in an overall increase in proliferation of VSMCs under both acute and chronic high glucose conditions as compared with normal glucose control (P < 0.0001). Application of both cyclic strain and cyclic strain shear resulted in a significant increase in percent apoptosis with chronic high glucose treatment in comparison with both normal glucose controls (P < 0.0001) and acute high glucose (P < 0.0001). Cellular hypertrophy as estimated by measuring cell area and aspect ratio revealed a significantly altered morphology due to concomitant loading under chronic high glucose conditions with significantly higher cell area (P < 0.0001) and lower aspect ratio (P < 0.0001) indicative of a relatively rounded morphology as compared with normal glucose controls. Western blot analysis demonstrated reduced expression of SM α-actin (P < 0.0001), calponin (P < 0.0001), and SM22α (P = 0.0008) for concomitant loading under chronic high glucose treatment as compared with normal glucose controls. CONCLUSIONS: Concomitant application of cyclic strain and low wall shear stress resulted in greater phenotypic modulation of VSMCs due to chronic high glucose treatment as compared with normal glucose controls, thus implicating cellular-response differences which may impact progression of in-stent restenosis in diabetic patients with poorly controlled hyperglycemia. Similarity of VSMC response from our study to existing preclinical models of diabetes and reports of altered phenotype of VSMCs isolated from diabetic patients substantiate the relevance of our dynamic disease test model.

An early validation of the Society for Vascular Surgery lower extremity threatened limb classification system.

OBJECTIVE: The Society for Vascular Surgery (SVS) recently established the Lower Extremity Threatened Limb Classification System, a staging system using Wound characteristic, Ischemia, and foot Infection (WIfI) to stratify the risk for limb amputation at 1 year. Although intuitive in nature, this new system has not been validated. The purpose of the following study was to determine whether the WIfI system is predictive of limb amputation and wound healing. METHODS: Between 2007 and 2010, we prospectively obtained data related to wound characteristics, extent of infection, and degree of postrevascularization ischemia in 139 patients with foot wounds who presented for lower extremity revascularization (158 revascularization procedures). After adapting those data to the WIfI classifications, we analyzed the influence of wound characteristics, extent of infection, and degree of ischemia on time to wound healing; empirical Kaplan-Meier survival curves were compared with theoretical outcomes predicted by WIfI expert consensus opinion. RESULTS: Of the 158 foot wounds, 125 (79%) healed. The median time to wound healing was 2.7 months (range, 1-18 months). Factors associated with wound healing included presence of diabetes mellitus (P = .013), wound location (P = .049), wound size (P = .007), wound depth (P = .004), and degree of ischemia (P < .001). The WIfI clinical stage was predictive of 1-year limb amputation (stage 1, 3%; stage 2, 10%; stage 3, 23%; stage 4, 40%) and wound nonhealing (stage 1, 8%; stage 2, 10%; stage 3, 23%; stage 4, 40%) and correlated with the theoretical outcome estimated by the SVS expert panel. CONCLUSIONS: The theoretical framework for risk stratification among patients with critical limb ischemia provided by the SVS expert panel appears valid. Further validation of the WIfI classification system with multicenter data is justified.

The influence of a Vascular Surgery Hospitalist program on physician and patient satisfaction, resident education, and resource utilization.

A number of surgery practice models have been developed to address general and trauma surgeon workforce shortages and on-call issues and to improve surgeon satisfaction. These include the creation of acute or urgent care surgery services and "surgical hospitalist" programs. To date, no practice models corresponding to those developed for general and trauma surgeons have been proposed to address these same issues among vascular surgeons or other surgical subspecialists. In 2003, our practice established a Vascular Surgery Hospitalist program. Since its inception nearly a decade ago, it has undergone several modifications. We reviewed hospital administrative databases and surveys of faculty, residents, and patients to evaluate the program's impact. Benefits of the Vascular Surgery Hospitalist program include improved surgeon satisfaction, resource utilization, timeliness of patient care, communication among referring physicians and ancillary staff, and resident teaching/supervision. Elements of this program may be applicable to a variety of surgical subspecialty settings.

Technical strategy for the endovascular management of ascending aortic pseudoaneurysm.

We present two cases of ascending aortic pseudoaneurysm exclusion with off-the-shelf aortic stent grafts. The right common carotid artery was used for access to facilitate graft delivery. Control of graft deployment was aided using a compliant right atrial occlusion balloon to lower cardiac output at the time of deployment. Transesophageal echocardiography facilitated the sizing and positioning of the right atrial balloon and was used to survey the heart and ascending aorta on successful exclusion of the pseudoaneurysm. These simple maneuvers made an uncommon procedure straight forward, predictable, and successful.

Influence of topography of an endovascular stent material on smooth muscle cell response.

The phenotypic shift of smooth muscle cells (SMCs) from contractile to synthetic phenotype after endovascular stenting has been deemed to be the predominant cause of restenosis. Although substrate topography has been shown to affect SMC response for a variety of polymers, effect of topography on phenotype of SMCs has not been well studied for endovascular stent materials. Thus, the objective of the present study was to evaluate SMC phenotype, manifested in morphology, proliferation, and contractile marker smooth muscle α-actin expression, as a function of 316L stainless steel topography. Results of this study showed that the cells grown on micro-grooved surface (groove depth: 13 µm) were significantly more elongated than those on the electropolished surface. Ascertained by repeated proliferation studies, cells grown on micro-grooved surface demonstrated a significantly lower proliferation rate relative to the electropolished surface. An enhanced expression of smooth muscle α-actin grown on micro-grooved surface was also found near confluence. Furthermore, cells on electropolished surface demonstrated a substantial loss of smooth muscle α-actin between days 1 and 4. Therefore, given the favorable SMC response reported in this study, our findings suggest that a micro-grooved topography might prove beneficial for endovascular stent applications.

Increased synthetic phenotype behavior of smooth muscle cells in response to in vitro balloon angioplasty injury model.

Restenosis remains a common problem following balloon angioplasty, and it has been speculated that changes in the mechanical environment due to endovascular interventions are correlated with shifts in smooth muscle cell (SMC) phenotype. In order to study SMC response to forces similar to those exerted during balloon angioplasty, an in vitro concurrent shear and tensile forces simulator has been developed. After 24 hr of exposure to cyclic tension (5%) and shear (0.1-0.5 dynes/cm(2)) following simulated angioplasty injury (12% stretch), rat aortic SMCs exhibited significant synthetic behavior. These responses included increased cell proliferation, apoptosis, and cell hypertrophy compared to cells exposed to strain alone. While all SMCs exposed to dynamic stimuli (strain, strain+balloon injury, strain+balloon injury+shear) demonstrated a decrease in contractile protein expression, the injury group also exhibited significantly greater expression of the synthetic marker vimentin. These in vitro findings agree with in vivo events following balloon angioplasty and present a refined dynamic model to be implemented for better understanding of SMC activation and prevention of responses through pharmacological treatment.

The impact of isolated tibial disease on outcomes in the critical limb ischemic population.

BACKGROUND: Most patients with critical limb ischemia (CLI) have multilevel infrainguinal peripheral arterial disease (M-PAD). One-third of CLI patients will have isolated tibial disease (ITD). The treatments for multilevel disease or ITD differ depending on whether open or endovascular procedures are used, but we questioned whether outcomes from these procedures differ. We evaluated outcomes of CLI patients after open and/or endovascular revascularization for CLI and assessed the impact of disease distribution. METHODS: Four hundred forty-six CLI patients (Rutherford 4-6) who underwent revascularization from 2001 to 2005 were evaluated arteriographically and followed after revascularization with noninvasive testing. Based on arteriographic data, all patients with ITD (occlusions in one or more tibial arteries) were compared with patients with occlusive femoropopliteal disease with or without concomitant tibial occlusions (M-PAD). Patients with disease solely above the inguinal ligament were excluded. Clinical data (survival, amputation-free survival, primary patency, secondary patency, limb salvage, maintenance of ambulation, and maintenance of living status) were acquired from a prospective vascular database, allowing the comparison of revascularization outcomes according to disease distribution. RESULTS: In this study, 36% of patients had ITD and 64% presented with M-PAD. The severity of ischemia at presentation was rest pain (28.5%), ulceration (42.3%), and gangrene (29.1%). In this study, 92% presented exclusively with infrainguinal disease, and 8% presented with both suprainguinal and infrainguinal disease. Risk factors included diabetes mellitus (61.2%), smoking (61.0%), coronary artery disease (57.9%), hypertension (84.3%), hyperlipidemia (40.4%), obesity (15.5%), and chronic obstructive pulmonary disease (19.3%). In comparing the ITD and M-PAD groups, there was no difference in primary patency at 2 years. All other outcomes were statistically different out to 3 years including survival (50.4% vs. 62.6%; p=0.0026, hazard ratio [HR] 0.669); amputation-free survival (35.1% vs. 50.2%; p=0.0062; HR 0.595); limb salvage (65.2% vs. 74.4%; p=0.0062; HR 0.595); maintenance of ambulation (68.9% vs. 76.9%; p=0.0352; HR 0.644); maintenance of living status (79.0% vs. 84.8%; p=0.0403; HR 0.599); and secondary patency (66.8% vs. 74.8%; p=0.0309; HR 0.665). Multivariate analyses reveal that ITD is not an independent predictor of outcome after controlling for confounding factors, of which tissue loss and end-stage renal disease correlate most consistently with poor clinical outcomes. CONCLUSION: After revascularization for CLI, ITD carries a worse prognosis (amputation-free survival, limb salvage, survival, maintenance of ambulation, and independent living status) compared with patients with M-PAD, despite the "greater" disease burden in M-PAD patients. ITD patients are more likely to have confounding factors such as diabetes mellitus, renal disease, and worse ischemia at presentation than those with M-PAD. The recognition of ITD may be helpful in identifying high-risk patients but is not an independent risk factor for poor outcomes.

Combinatorial therapy of sirolimus and heparin by nanocarrier inhibits restenosis after balloon angioplasty ex vivo.

Aim: To develop poly(lactide-co-glycolide)-graft-polyethylenimine (PgP) as a dual drug-delivery carrier for sirolimus (SR) and heparin (Hep) to inhibit restenosis after balloon angioplasty. Materials & methods: SR was loaded in the hydrophobic core and negatively charged Hep complexed with the positively charged hydrophilic shell of PgP. SR- and Hep-loaded PgP was tested on rat aortic smooth muscle cells in vitro and injured porcine coronary arteries after balloon angioplasty ex vivo. Results & conclusion: SR and Hep loading efficiency in PgP were approximately 37 and 82%, respectively. SR- and Hep-loaded PgP treatment decreased smooth muscle cell proliferation up to 14 days post-treatment and decreased proliferation, collagen deposition and neointimal thickness and increased patency in porcine coronary arteries after balloon angioplasty ex vivo.

Clinical success using patient-oriented outcome measures after lower extremity bypass and endovascular intervention for ischemic tissue loss.

INTRODUCTION: Successful outcome after lower extremity revascularization is usually measured by physician-oriented terms such as graft patency and amputation-free survival. It has been increasingly appreciated that these criteria do not necessarily translate into success from the prospective of the patient. The purpose of this study, therefore, is to retrospectively examine success after lower extremity revascularization for tissue loss using patient-oriented measures and to include patients who underwent both open surgical bypass and endovascular therapy. METHODS: Between 1998 and 2005, 677 patients (316 endovascular and 361 open surgery) underwent revascularization for ischemic tissue loss. The method of revascularization (endovascular or open surgery) was left to the discretion of the surgeon. Revascularization was considered to be clinically successful if each of the following occurred: reconstruction patency until wound healing, limb salvage for 1 year, maintenance of ambulation for 1 year, and survival for 6 months. The influence of 20 intrinsic patient factors, including type of revascularization (open vs endo) was examined using the chi(2) test. Significant factors in bivariate analysis were included in a logistic regression model to determine independent predictors and probability of failure. RESULTS: Overall clinical success was achieved in 277 (40.9%) patients. Success for open surgical and endovascular cohorts was 44.3% and 37.0%, respectively (P = .06). Type of intervention was not a significant factor in either bivariate or logistic regression analysis. Independent predictors of failure (odds ratio [OR]; 95% confidence interval [CI]) regardless of treatment type included impaired ambulatory status at the time of presentation (OR 3.24; CI 2.14, 4.90), diabetes (OR 1.62; CI 1.14, 2.32), endstage renal disease (ESRD) (OR 1.55; CI 1.07, 2.23), presence of gangrene (OR 2.0; CI 1.42, 2.82), and prior vascular intervention (OR 1.46; CI 1.02, 2.10). Paradoxically, hyperlipidemia (OR 0.70; CI 0.50, 0.98) was a predictor for success. Probability of failure was 35.4% (OR 1.0) if no independent predictors were present and increased with the addition of each adverse predictor. For instance, diabetic patients with impaired ambulatory status and gangrene had an 85.2% (OR 10.5) probability of failure. In the worst case scenario, a diabetic patient with ESRD, impaired ambulatory status, gangrene, and a prior vascular intervention was considered, probability of failure was a dismal 92.8% (OR 23.7). CONCLUSION: Clinical success after lower extremity revascularization for ischemic tissue loss is determined by intrinsic patient factors and not by method of revascularization. These data reiterate that future investigation efforts should be focused less on the method of revascularization and more on identification of patient cohorts at risk for failure regardless of treatment.

Changing indications and outcomes for open abdominal aortic aneurysm repair since the advent of endovascular repair.

The indications for open abdominal aortic aneurysm (AAA) repair have changed with the development of endovascular techniques. The purpose of this study is to clarify the indications and outcomes for open repair since endovascular aneurysm repair (EVAR) and to compare contemporary AAA repair with the pre-EVAR era. Patients undergoing open AAA repair were identified; the demographics, outcomes, and indications for open repair were reviewed. Outcomes were compared based on indication for open repair in the EVAR era and between the pre-EVAR and EVAR eras. Open indications in the EVAR era included: age younger than 65 years with minimal comorbidities (AGE, n = 24 [9.8%]), unfavorable anatomy (ANAT, n = 146 [59.3%]), aortoiliac occlusive disease (AIOD, n = 38 [15.4%]), and miscellaneous (OTHER, n = 38 [15.4%]). Mortality (30-day and 5-year) was affected by indication: AGE = 0 and 0 per cent, ANAT = 4.1 and 49.7 per cent, AIOD = 13.5 and 32.3 per cent, and OTHER = 5.3 and 41.8 per cent. Age, sex, race, coronary artery disease, and peripheral artery disease were similar between the pre-EVAR and EVAR eras. EVAR-era patients had more diabetes mellitus, hypertension, and hyperlipidemia and longer operative time. Mortality was not different, but complication rates were lower in the pre-EVAR era (23.7 vs 43.5%, P = 0.025). Patients undergoing open AAA repair in the EVAR era have more comorbidities, longer operative times, and more complications. Outcomes for EVAR-era patients are affected by the indication for open repair. A preference for open repair in younger patients with minimal comorbidities is justified.

Evaluation of the diameter of the proximal descending thoracic aorta with age: implications for thoracic aortic stent grafting.

BACKGROUND: Long-term anatomical changes of the thoracic aorta which may affect long-term outcome of blunt aortic injuries treated with endovascular stent grafts are unknown. The purpose of this study was to examine the natural history of thoracic aortic diameter with progressing age. METHODS: One thousand consecutive thoracic computed tomographic scans performed for nonthoracic aortic pathology on patients aged 15-99 (mean 59.4) were examined, and thoracic aortic diameter immediately adjacent to the left subclavian artery was measured. Factors possibly influencing diameter, including age by decade of life, race, gender, history of hypertension (HTN), diabetes mellitus (DM), chronic obstructive pulmonary disease (COPD), and tobacco use, were examined. Factors were compared using Student's t-test. RESULTS: The differences in mean diameters of the thoracic aorta by gender (male=27.1 vs. female=26.0, p=0.87), race (Caucasian=26.6 vs. non-Caucasian=26.3, p=0.10), presence of HTN (yes=25.8 vs. no=24.9, p=0.36), COPD (yes=26.3 vs. no=25.4, p=0.21), DM (yes=26.1 vs. no=25.3, p=0.12), and tobacco use (yes=26.3 vs. no=25.0, p=0.18) were not significant. However, differences in mean diameter increased significantly over time with age. Patients under 40 years old had mean aortic diameters of 22.92 mm compared to 27.09 mm (p<0.001) for patients over 40. The mean aortic isthmus diameter showed an approximately 1cm increase when comparing octogenarians to teenagers. CONCLUSION: The diameter of the aortic isthmus increases substantially with age. These findings suggest that long-term surveillance is warranted for trauma patients with aortic stent grafts, to monitor the natural history and to assess for possible late complications.

The utility of the StarClose arterial closure device in patients with peripheral arterial disease.

The StarClose (Abbott Vascular, Redwood City, CA) arterial closure device utilizes an extraluminal nitinol clip to establish hemostasis. The purpose of this study was to determine the safety and efficacy of StarClose from a prospective peripheral arterial disease (PAD) registry. Over an 18-month time interval, 500 StarClose devices were used in 378 consecutive patients with symptomatic PAD after diagnostic and/or therapeutic endovascular cases. Patient demographics along with objective criteria including duplex ultrasound images, common femoral artery flow velocities, and ankle-brachial indexes (ABIs) were analyzed before and after StarClose placement. All outpatients received prophylactic antibiotic (one dose), periprocedural heparin (without protamine reversal), and antiplatelet therapy. Aspirin and clopidogrel (Plavix) was used for all patients undergoing therapeutic intervention. There were 378 patients who underwent procedures for aortoiliac or infrainguinal PAD, 99 of which were bilateral. Of the 500 arteriotomy closures, 296 were therapeutic interventions with sheath sizes of 6-8 F in the common femoral artery. The diagnostic studies (n = 204 arteriotomies) were performed with a 5F sheath. The technical success in achieving hemostasis was 97.2%; only 14 devices had a deployment problem requiring prolonged manual compression. Median length of stay was 157 min for patients done on an outpatient basis. Eleven of 260 (4.2%) on duplex follow-up had a doubling of the peak systolic velocity, only one of which was symptomatic. Late follow-up showed 42 of 360 (11.7%) with a drop in ABI >0.10. Nine major complications (2.0%) were identified in follow-up. The StarClose closure device has a low major complication rate and is safe and efficacious in patients with PAD, although stenosis at the arteriotomy site may occur. The device has achieved rapid hemostasis without need for anticoagulant reversal and requires significantly less time to ambulation than manual compression.

Contemporary outcomes of iliofemoral bypass grafting for unilateral aortoiliac occlusive disease: a 10-year experience.

Current treatment of complex aortoiliac occlusive disease (AIOD) includes the aortobifemoral bypass or the femoral-femoral bypass. However, because of bilateral groin exposure and associated risks, there is a significant morbidity associated with these procedures. In appropriate patients with unilateral AIOD, the iliofemoral bypass graft (IFBPG) via a lower abdominal retroperitoneal incision can be an acceptable alternative. The purpose of this study is to review the safety and efficacy as well as long-term outcomes of IFBPG in patients with unilateral AIOD. From July 1997 through June 2006, 40 patients (64.3 +/- 11.2-years-old, range 41-89-years-old, 57.5% critical limb ischemia, 70% male, 95% smokers) with unilateral AIOD were treated with IFBPG. Perioperative complications and symptom resolution were measured and Kaplan-Meier life table analysis was used to analyze outcomes of primary and secondary patency, survival, limb salvage, contralateral intervention, and maintenance of ambulation and independent living status. The perioperative complication rate was 12.5 per cent (n = 5) including one patient who developed atrial-fibrillation and one who developed acute renal failure. Both patients experienced resolution of these symptoms before discharge. Other complications included one limb thrombosis and two wound infections. There were no perioperative deaths. Secondary patency was 97.5 per cent and 93.3 per cent at 1 and 5 years. Limb salvage in patients with critical limb ischemia (CLI) was 85.1 per cent and 79.1 per cent at 1 and 5 years. Limb amputation occurred due to infection (n = 2), or failed IFBPG (n = 2). Thirty-one patients (77.5%) experienced symptom resolution including 15 (88.2%) of the patients treated for claudication. Two patients (5%) required contralateral iliac intervention. Patient survival was 97.5 per cent and 64.5 per cent at 1 and 5 years. Greater than 90 per cent of patients maintained their functional independence at 5 years. IFBPG achieved excellent technical and functional outcomes, particularly in patients treated for vasculogenic claudication. This procedure is relatively safe and efficacious in a population of patients with complex unilateral AIOD and can be an acceptable alternative to the aortobifemoral bypass or fem-fem procedure.

Critical analysis of clinical success after surgical bypass for lower-extremity ischemic tissue loss using a standardized definition combining multiple parameters: a new paradigm of outcomes assessment.

BACKGROUND: Success after surgical revascularization of the lower extremities, traditionally defined by graft patency or limb salvage, fails to consider other intuitive measures of importance. The purpose of the study was to construct a more comprehensive definition of clinical success and to identify clinical predictors of failure. STUDY DESIGN: For the purpose of this study, clinical success was defined as achieving all of the following criteria: graft patency to the point of wound healing; limb salvage for 1 year; maintenance of ambulatory status for 1 year; and survival for 6 months. Between 1998 and 2004, 331 consecutive patients undergoing bypass for Rutherford III critical limb ischemia were measured for clinical success. Bivariate and logistic regression analyses were performed to determine demographic differences between success and failure. RESULTS: Despite achieving acceptable graft patency (72.7% at 36 months) and limb salvage (73.3% at 36 months), clinical success combining all 4 defined parameters was only 44.4%. Independent predictors of failure included impaired ambulatory status at presentation (odds ratio [OR] = 6.44), presence of infrainguinal disease (OR = 3.93), end-stage renal disease (OR = 2.48), presence of gangrene (OR = 2.40), and hyperlipidemia (OR = 0.56). Probability of failure in patients possessing every predictor except hyperlipidemia at presentation was 97% (OR = 150.6). CONCLUSIONS: Despite achieving acceptable graft patency and limb salvage, fewer than half of the patients achieved success when using a definition combining multiple parameters. A reappraisal of our current approach to critical limb ischemia in certain high-risk patients is warranted.

Is incidental renal arteriography justified in a population of patients with symptomatic peripheral arterial disease?

Renal artery stenosis is a consequence of generalized atherosclerosis and many specialists perform routine selective renal angiography to detect and treat renal artery stenosis. The incidence of clinically important renal artery stenosis is not well defined in patients with symptomatic peripheral arterial disease. The purpose of this study was to better delineate the incidence of and the risk factors associated with renal artery stenosis, renovascular hypertension, and ischemic nephropathy incidentally discovered during angiography for symptomatic peripheral arterial disease. Two hundred consecutive patients undergoing angiographic evaluation of symptomatic lower extremity peripheral arterial disease were studied retrospectively. Angiograms were reviewed for the presence of renal artery stenosis (defined as >or= 25% diameter reduction in either renal artery) and findings were then correlated to the clinical diagnosis of renovascular hypertension (> 50% renal artery stenosis and >or= 3-drug resistive hypertension) and ischemic nephropathy (defined as > 50% bilateral renal artery stenosis, 3-drug hypertension, and creatinine >or= 1.5). Angiographic findings were also correlated with risk factors to determine if a relationship correlated to the presence of and degree of renal artery stenosis. Data were analyzed using the Student's t test, Chi-square model, and multiple logistic regression analysis. The overall incidence of any degree of renal artery stenosis in this study population was 26% (52 patients). Only 24 (12%) patients had an incidental finding of >or= 50% stenosis in either renal artery. Six (3%) of these patients were found to have associated renovascular hypertension. Additionally, 9 (4.5%) patients had coexistent renal insufficiency and significant renal artery stenosis; five with end-stage renal disease on chronic hemodialysis. Only one patient with end-stage renal disease had poorly controlled 3-drug hypertension. Thus definitive ischemic nephropathy was present in only one (0.5%) patient. Statistically significant risk factors associated with the presence of renal artery stenosis include hypertension (P < .001), coronary disease (P = .024), female gender (P = .010), diabetes (P = .039), aorto-iliac disease (P = .031), multiple levels of peripheral arterial disease (P < .001), and age over 60 ( P < .001). While the incidence of renal artery stenosis in patients being evaluated for symptomatic peripheral arterial disease is similar to that reported in the cardiology literature, the incidence of renovascular hypertension and ischemic nephropathy is exceedingly low (3% and 0.5%, respectively)-findings similar to data reported in the general hypertensive population. These data suggest that incidental selective renal angiography is not justified in patients with symptomatic peripheral arterial disease.

Is surgical thrombectomy to salvage failed autogenous arteriovenous fistulae worthwhile?

The Dialysis Outcomes Quality Initiatives guidelines emphasize placement of autogenous arteriovenous (AV) fistulae for patients on hemodialysis. This recommendation is based on studies that demonstrate enhanced patency for AV fistulae compared with grafts. However, closer review of the data demonstrates that although primary patency of AV fistulae is superior to grafts, the secondary patency rates are equivalent. This suggests that secondary procedures to maintain fistula patency are inferior to those performed on arteriovenous grafts. Surgical thrombectomy of AV fistulae can be challenging. It is often difficult to completely remove thrombus adjacent to the anastomosis of the fistula, and pseudoaneurysms within the fistula can prevent passage of the thrombectomy catheter and complete removal of thrombus from the fistula. Consequently, some surgeons simply abandon thrombosed AV fistulae and place a new access. We have developed a method for completely clearing thrombus from failed AV fistulae by locating the fistulotomy close to the arterial anastomosis and using a technique to manually extract thrombus from the fistula before passing a thrombectomy catheter. The purpose of this study was to review our results with this procedure. Between 2001 and 2004, 10 patients with a previously functioning AV fistula presented with thrombosis. There were seven brachiocephalic fistulae and three radiocephalic fistulae. All patients underwent surgical thrombectomy and fistulography. Five patients underwent balloon angioplasty of a venous stenosis and one patient underwent surgical revision of an arterial stenosis. Technical success, defined as being able to completely clear thrombus from the fistula and treat the cause for fistula failure, was achieved in 70 per cent (7/10) of cases. Technical failure was caused by vein rupture during the balloon angioplasty in two cases and a central venous occlusion that could not be treated in one case. The 6-month primary and secondary patency for cases that were technically successful was 51 and 69 per cent, respectively. Our conclusion was that surgical thrombectomy can significantly extend fistula functionality in patients who present with thrombosis.

The mid-thigh loop arteriovenous graft: patient selection, technique, and results.

As patient longevity on hemodialysis has increased, surgeons are increasingly challenged to provide vascular access to patients who have exhausted options for access in the upper extremity. A common operation performed on these patients has been the loop thigh arteriovenous (AV) graft based off the common femoral vessels. However, there are several disadvantages of placing prosthetic grafts in proximity to the groin. Our group has modified the thigh loop AV graft procedure by moving the anastomoses to the mid-superficial femoral artery and vein. The advantage of this location is that it preserves the proximal femoral vessels for graft revision and avoids the node-bearing tissue and overhanging panniculus of the groin. The purpose of this study was to review our technique, patient selection, and experience with the mid-thigh loop AV graft procedure. Between 2001 and 2003, 46 mid-thigh loop AV grafts were placed in 38 patients. Patient hospital, office, and dialysis clinic records were reviewed. The primary and secondary patency for AV grafts in this study by life-table was 40 per cent and 68 per cent at 1 year and 18 per cent and 43 per cent at 2 years. There were 10 infections (21%) requiring graft removal. Four patients underwent subsequent placement of a proximal loop thigh AV graft after mid-thigh graft failure. Patient survival was 86 per cent at 1 year and 82 per cent at 2 years. There were no patient deaths related to thigh graft placement. Our results with the mid-thigh loop AV graft compare favorably with published results for thigh loop AV grafts. The procedure preserves the proximal vasculature, permitting graft revision or subsequent proximal graft placement, and may be associated with fewer infectious complications. The mid-thigh loop AV graft procedure should be considered before placement of a thigh loop AV graft based off the common femoral artery and vein.

Does obesity predict functional outcome in the dysvascular amputee?

Limited information is available concerning the effects of obesity on the functional outcomes of patients requiring major lower limb amputation because of peripheral arterial disease (PAD). The purpose of this study was to examine the predictive ability of body mass index (BMI) to determine functional outcome in the dysvascular amputee. To do this, 434 consecutive patients (mean age, 65.8 +/- 13.3, 59% male, 71.4% diabetic) undergoing major limb amputation (225 below-knee amputation, 27 through-knee amputation, 132 above-knee amputation, and 50 bilateral) as a complication of PAD from January 1998 through May 2004 were analyzed according to preoperative BMI. BMI was classified according to the four-group Center for Disease Control system: underweight, 0 to 18.4 kg/m2; normal, 18.5 to 24.9 kg/m2; overweight, 25 to 29.9 kg/m2; and obese, > or = 30 kg/m2. Outcome parameters measured included prosthetic usage, maintenance of ambulation, survival, and maintenance of independent living status. The chi2 test for association was used to examine prosthesis wear. Kaplan-Meier curves were constructed to assess maintenance of ambulation, survival, and maintenance of independent living status. Multivariate analysis using the multiple logistic regression model and a Cox proportional hazards model were used to predict variables independently associated with prosthetic use and ambulation, survival, and independence, respectively. Overall prosthetic usage and 36-month ambulation, survival, and independent living status for the entire cohort was 48.6 per cent, 42.8 per cent, 48.1 per cent, 72.3 per cent, and for patients with normal BMI was 41.5 per cent, 37.4 per cent, 45.6 per cent, and 69.5 per cent, respectively. There was no statistically significant difference in outcomes for overweight patients (59.2%, 50.7%, 52.5%, and 75%) or obese patients (51.8%, 46.2%, 49.7%, and 75%) when compared with normal patients. Although there were significantly poorer outcomes for underweight patients for the parameters of prosthetic usage when compared with the remaining cohort (25%, P = 0.001) and maintenance of ambulation when compared with overweight patients (20.8%, P = 0.026), multivariate analysis adjusting for medical comorbidities and level of amputation showed that BMI was not a significant independent predictor of failure for any outcome parameter measured. In conclusion, BMI failed to correlate with functional outcome and, specifically, obesity did not predict a poorer prognosis.