Outcomes and predictors of amputation-free survival in patients undergoing below-knee popliteal-distal bypass.

OBJECTIVE: The infrageniculate popliteal artery is a potential source for inflow in lower extremity bypass surgery in patients with isolated tibial artery disease. The objective of our study was to assess the short- and long-term outcomes of popliteal-distal bypasses using data from the Vascular Quality Initiative (VQI). METHODS: The VQI registry was queried between 2003 and 2021 for patients undergoing surgical revascularizations with the below-knee popliteal artery serving as inflow. Demographics, comorbidities, intraoperative characteristics, and postoperative complications were analyzed. Kaplan-Meier models were used to estimate amputation-free survival, survival, and freedom from amputation. Cox regression analysis was conducted to determine factors associated with major amputation or death. RESULTS: A total of 1884 procedures were analyzed. The mean age of the included patients was 67.7 years. The most frequently observed preoperative comorbidities included insulin-dependent diabetes (52.3%), coronary disease (32.4%), and end-stage renal disease (14.4%). Of all the patients, 670 (35.6%) had a history of ipsilateral endovascular intervention. The procedures were performed for a variety of indications, including tissue loss (84.3%), rest pain (10.9%), and claudication (4.8%). Intraoperatively, the outflow targets were the dorsalis pedis (31.4%), the posterior tibial (24.4%), and the anterior tibial arteries (15.6%). Vein conduit was used in 92.1% of cases. The rate of perioperative myocardial infarction (MI) was 2.4%, and the 30-day mortality was 1.9%. The median length of follow up was 371 days. Amputation-free survival was found to be 85.6% (95% confidence interval [CI], 84.0%-87.2%) at 6 months and 78.6% (95% CI, 76.6%-80.4%) at 12 months. Survival was found to be 93.4% (95% CI, 92.2%-94.5%) at 6 months and 88.6% (95% CI, 87.1%-90.0%) at 12 months. Freedom from amputation was found to be 92.0% (95% CI, 90.7%-93.3%) at 6 months and 89.0% (95% CI, 87.3%-90.4%) at 12 months. Cox regression analysis demonstrated that age greater than 65 years, congestive heart failure, coronary artery disease, and end-stage renal disease were associated with a higher risk of major amputation or death (P < .05). CONCLUSIONS: Below-knee popliteal-distal bypass is a safe and effective approach to treat severe tibial vessel occlusive disease in this challenging patient cohort. Patients exhibited low perioperative complication rates and good amputation-free survival at 1 year.

A comparison of endovascular repair to medical management for acute vs subacute uncomplicated type B aortic dissections.

OBJECTIVE: Thoracic endovascular aortic repair (TEVAR) has emerged as a viable option of treatment for uncomplicated type B aortic dissection (UTBAD) due to the potential for inducing favorable aortic remodeling. The aim of this study is to compare outcomes of UTBAD treated medically or with TEVAR in either the acute (1 to 14 days) or subacute period (2 weeks to 3 months). METHODS: Patients with UTBAD between 2007 and 2019 were identified using the TriNetX Network. The cohort was stratified by treatment type (medical management; TEVAR during the acute period; TEVAR during the subacute period). Outcomes including mortality, endovascular reintervention, and rupture were analyzed after propensity matching. RESULTS: Among 20,376 patients with UTBAD, 18,840 were medically managed (92.5%), 1099 patients were in the acute TEVAR group (5.4%), and 437 patients were in the subacute TEVAR group (2.1%). The acute TEVAR group had higher rates of 30-day and 3-year rupture (4.1% vs 1.5%; P < .001; 9.9% vs 3.6%; P < .001) and 3-year endovascular reintervention (7.6% vs 1.6%; P < .001), similar 30-day mortality (4.4% vs 2.9%; P < .068), and lower 3-year survival compared with medical management (86.6% vs 83.3%; P = .041). The subacute TEVAR group had similar rates of 30-day mortality (2.3% vs 2.3%; P = 1), 3-year survival (87.0% vs 88.8%; P = .377) and 30-day and 3-year rupture (2.3% vs 2.3%; P = 1; 4.6% vs 3.4%; P = .388), with significantly higher rates of 3-year endovascular reintervention (12.6% vs 7.8%; P = .019) compared with medical management. The acute TEVAR group had similar rates of 30-day mortality (4.2% vs 2.5%; P = .171), rupture (3.0% vs 2.5%; P = .666), significantly higher rates of 3-year rupture (8.7% vs 3.5%; P = .002), and similar rates of 3-year endovascular reintervention (12.6% vs 10.6%; P = .380) compared with the subacute TEVAR group. There was significantly higher 3-year survival (88.5% vs 84.0%; P = .039) in the subacute TEVAR group compared with the acute TEVAR group. CONCLUSIONS: Our results found lower 3-year survival in the acute TEVAR group compared with the medical management group. There was no 3-year survival benefit found in patients with UTBAD who underwent subacute TEVAR compared with medical management. This suggests the need for further studies looking at the necessity for TEVAR when compared with medical management for UTBAD as it is non-inferior to medical management. Higher rates of 3-year survival and lower rates of 3-year rupture in the subacute TEVAR group compared with the acute TEVAR group suggest superiority of subacute TEVAR. Further investigations are needed to determine the long-term benefit and optimal timing of TEVAR for acute UTBAD.

A Propensity-Matched Analysis of Endovascular Intervention versus Open Nonautologous Bypass as Initial Therapy in Patients with Chronic Limb-Threatening Ischemia.

OBJECTIVES: Endovascular therapies are increasingly used in patients with complex multilevel disease and chronic limb-threatening ischemia (CLTI). Infrageniculate bypass with autologous vein conduit is considered the gold standard in these patients. However, many patients often lack optimal saphenous vein, leading to the use of nonautologous prosthetic conduit. We compared limb salvage and survival rates for patients with CLTI undergoing first time revascularization with either open nonautologous conduit or endovascular intervention. METHODS: We retrospectively reviewed consecutive patients undergoing first time endovascular or open surgical revascularization at our institution between 2009 and 2016. Patients were divided into endovascular intervention or open bypass with nonautologous conduit (NAC) cohorts. Primary endpoints were amputation-free survival (AFS), freedom from reintervention, primary patency, and overall survival. Propensity scoring was used to construct matched cohorts. Outcomes were evaluated using Kaplan-Meier and Cox Proportional Hazards models. RESULTS: A total of 125 revascularizations were identified. There were 65 endovascular interventions and 60 NAC bypasses. In unmatched analysis, there was an elevated risk of perioperative MI (7% vs. 0%, P = 0.05) and amputation (10% vs. 2%, P = 0.04) for the NAC groups compared to the endovascular group. In matched analysis, endovascular patients had a lower incidence of 30-day amputation (1.5% vs. 10% P = 0.04) and length of stay (median days, 1 vs. 9, P < 0.01) compared to the open cohort. While not statistically significant, the endovascular group trended towards increased rates of two-year AFS (76% vs. 65%, P = 0.07) compared to the NAC group. There was no significant difference in overall survival when the endovascular cohort was compared to NAC (85% vs. 77%, P = 0.29) patients. In matched Cox analysis, nonautologous conduit use was associated with an increased risk of limb loss (HR 2.03, 95% CI 0.94-4.38, P = 0.07) compared to endovascular revascularization. CONCLUSIONS: An "endovascular first" approach offers favorable perioperative outcomes and comparable AFS compared to NAC and may be preferable when autologous conduit is unavailable.

Primary Patency of Long-Segment Femoropopliteal Artery Lesions in Patients with Peripheral Arterial Occlusive Disease Treated with Paclitaxel-Eluting Technology.

BACKGROUND: The aim of this study is to evaluate the performance and predictors of failure of paclitaxel drug-eluting stents and paclitaxel-coated balloons in the treatment of long-segment femoropopliteal disease. We report a retrospective cohort analysis of patients treated with paclitaxel-eluting stents and paclitaxel-coated balloons in lesions >100 mm, which were not included in any of the pivotal trials. METHODS: Ninety-seven patients with peripheral vascular disease (Rutherford III-VI) underwent long-segment (≥100 mm) femoropopliteal drug-eluting stent (DES) implantation or angioplasty with drug-coated balloons (DCB). Patients were followed after their initial procedure for target lesion restenosis, defined as a reduction in lumen diameter by greater than 50% as measured by duplex ultrasonography (ratio >2). RESULTS: The median length of the affected arterial segments was 110 mm (interquartile range [IQR] 100-150, absolute range 100-260) using up to 4 overlapping stents. During the median 13-month follow-up (IQR 7-16), no early thrombotic occlusions occurred within 30 days, but 28 (29%) patients developed a target lesion restenosis after 1 year. Cumulative primary patency at 6 and 12 months was 87% and 71% overall, respectively. The cumulative patency during the same follow-up periods varied between patients treated with different paclitaxel modalities with 88% and 80% primary patency in patients treated with DES (n = 63) versus 81% and 49% in patients treated with DCB (n = 21) (adjusted hazard ratio 2.46, P = 0.03). Lesion length, concurrent tibial intervention, and recurrent target lesions were not associated with restenosis. CONCLUSIONS: Short-term outcomes in patients treated with paclitaxel-eluting stents and paclitaxel-coated balloons in long lesions, mirror results from the clinical trials. The primary patency observed in patients treated with DES was significantly higher than in patients treated with DCB.

Amputation-free Survival in Patients with Critical Limb Ischemia Treated with Paclitaxel-eluting Stents and Paclitaxel-coated Balloons.

OBJECTIVE: The aim of this study was to evaluate the performance of paclitaxel-eluting stents (PESs) and paclitaxel-coated balloons (PCBs) on amputation-free survival in patients with critical limb ischemia (CLI). METHODS: A retrospective review of all patients with Rutherford stage 5 and 6 limb ischemia undergoing endovascular revascularization with paclitaxel-related technology, both PES and PCB, was carried out over a 4-year period. Clinical grading was determined by Rutherford classification and the Society for Vascular Surgery's Wound, Ischemia, and foot Infection (WIfI) scoring system. Clinical and angiographic follow-up was reviewed based on intention-to-treat analysis. The primary endpoint of this study was amputation-free survival at 12 months. Secondary endpoints included wound healing, freedom from target lesion revascularization, and patency of target vessels at 12 months. Follow-up occurred at 3, 6, and 12 months postoperatively. Target lesion patency was defined as <50% stenosis, based on a duplex velocity ratio of less than or equal to 2. Postoperative ankle-brachial index (ABI) and duplex ultrasound were performed to verify successful treatment. Outcomes were evaluated using Kaplan-Meier and Cox proportional-hazards models. RESULTS: A total of 88 limbs were revascularized in 88 patients. Drug-eluting stent (DES) was used as the sole drug technology in 56 patients (60.7% men, median age 70.5 years) and drug-coated balloon (DCB) was used as the sole drug technology in 32 patients (46.9% men, median age 66 years). Baseline demographics were well matched except for a higher prevalence of occluded target lesions in the DES group (41.1% vs. 12.5%; P = 0.004). Limbs were treated for Rutherford stage 5 CLI in 71.6% and stage 6 CLI in 28.4%. Univariate analysis identified no dependent factors affecting limb salvage, except for the use of DCBs. After 12 months of follow-up, amputation-free survival was significantly higher in the DES group than in the DCB group (88.5% vs. 71.1%; P = 0.0443). Wound healing rates after 1 year were also higher in the DES group (83.9% vs. 59.4%; P = 0.0198). Freedom from target lesion revascularization was no different between patients treated with DESs and patients treated with DCBs (90.6% vs. 85.7%; P = 0.518). Primary patency at 12 months in patients treated with DESs was significantly higher than in patients treated with PCBs (80.4% vs. 58.1%; P = 0.0255). CONCLUSIONS: Overall, drug technology represents a viable option for patients with CLI; a cohort not represented in major randomized trials. In our experience, femoropopliteal lesions treated with DESs have higher primary patency rates than those treated with DCBs. This was found to support higher amputation-free survival rates in patients treated with paclitaxel DESs than those treated with paclitaxel DCB. The use of paclitaxel DESs for CLI was also associated with significantly improved wound healing compared with DCBs. Our data suggest improved outcomes with DESs compared with DCBs; however, these patients represent a nonrandomized, heterogenous group that were treated with the operator's best judgment.

Underutilization of Nonopioid Pain Medication in Patients Undergoing Abdominal Aortic Aneurysm Repair.

BACKGROUND: With increased focus on the opioid crisis, it was our goal to describe rates and risk factors for postoperative use of opioids in patients undergoing abdominal aortic aneurysm (AAA) repair as well as identify pain modalities that are underutilized. METHODS: We retrospectively analyzed perioperative analgesic prescriptions for endovascular (EVAR) and open AAA repair between January 1, 2010 and January 1, 2018. Patients' baseline opioid use, demographics, and medical comorbidities were obtained. The EVAR group was further subdivided into percutaneous (pEVAR) and cutdown (cEVAR) groups. Primary outcomes were postoperative and discharge pain medication prescriptions. Relative rates of opioid prescribing were obtained through the electronic medical record and normalized into morphine milligram equivalents (MMEs). RESULTS: Of the 128 patients analyzed in the entire cohort, 21.8% (n = 28) underwent open repair and 78.12% (n = 100) underwent EVAR (46 pEVAR, 54 cEVAR). As expected, open repair had increased postoperative pain reported compared to EVAR (2.67 ± 0.75 vs. 0.96 ± 0.19, P < 0.01). Adjunctive epidural reduced postoperative pain for open repair (0.77 ± 0.48 vs. 3.50 ± 0.96, P < 0.01). EVAR had less postoperative opioid prescriptions compared to open repair (35.0% vs. 77.3%, P < 0.01). In the endovascular group, there was no difference between postoperative opioid prescription based on access, pEVAR versus cEVAR (65.8% vs. 80.1%, P = 0.11). When stratifying patients by number of cutdowns, patients with bilateral cutdown as opposed to a single cutdown received more opioid prescriptions than pEVAR patients (84.44% vs. 65.8%, P = 0.036). Of those receiving opioids, the average MME for open repair was 320.94 mg compared to 28.82 mg for EVAR (P < 0.01). Those undergoing percutaneous repair had significantly less MME use during hospitalization compared to femoral cutdown (17 ± 3.52 vs. 31.90 ± 5.43 mg, P < 0.01). Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and ketorolac, were rarely used in the postoperative period for open or EVAR (8.3% vs 1.1%). Percutaneous EVAR patients reported less pain at discharge compared to cEVAR patients (0.18 ± 0.12 vs. 0.88 ± 0.29, P = 0.036). Open and EVAR had comparable low rates of NSAID and acetaminophen prescriptions at discharge. Open patients had longer postoperative length of stay compared to EVAR patients (9.82 ± 1.27 vs. 3.86 ± 0.47, P < 0.01). pEVAR had a shorter length of postoperative course compared to cEVAR (3.2 ± 0.26 vs. 4.12 ± 0.30, P < 0.01). Patients undergoing EVAR with use of pain medications amounting to <20 MME had a significantly shorter length of stay. CONCLUSIONS: This single institutional retrospective study evaluated pain prescription patterns for patients undergoing AAA repair. AAA patients are predominantly treated with opioid pain medications with few adjunctive therapies. Intraoperative epidural and pEVAR may aid in decreasing the total MME used; however, the total number of opioids prescribed is similar for pEVAR and cEVAR despite the difference in approach. Clinicians must consider alternative nonopioid based pain management strategies.

Repair of Isolated Innominate Artery Pathology with a Modified Endovascular Graft.

Innominate artery pathology is traditionally treated with open surgical repair and is associated with significant morbidity. No dedicated endovascular solution exists for this anatomic location. We report a series of 3 cases of successful management of innominate artery injuries using an off-label, modified Zenith ESLE stent graft (Cook Medical, Bloomington, IN). Two patients presented with pseudoaneurysms after attempted central venous catheterization, and 1 patient developed a tracheo-innominate fistula. Access was obtained in a retrograde fashion via the right common carotid artery in 2 cases, and via the right axillary artery in the other. Additional anatomic considerations included a prior sternotomy in 2 cases and a bovine arch in 2 cases. Due to the emergent nature of the cases, no cerebral protection maneuvers were taken. The ESLE limbs are of uniform diameter with 3 Z-stent wireforms and measure 55 mm in length. Removal of the distal stent reduces the length to 38 mm. Fourteen- to 18-mm diameter grafts were used. All 3 cases resulted in technical success with complete exclusion of the defect. There were no new neurologic deficits and all patients recovered uneventfully. This approach represents an effective off-label solution for what frequently presents as an emergent problem. In 2 cases, it obviated the need for a complicated redo sternotomy and facilitated endovascular repair in a vessel for which there was no indicated off-the-shelf conduit. Modification of existing devices successfully addressed the need for a nontapered graft of short length and moderate vessel diameter and allowed for minimally invasive treatment of anatomically complex pathology.

Factors Associated with Ipsilateral Limb Ischemia in Patients Undergoing Femoral Cannulation Extracorporeal Membrane Oxygenation.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is an important life-saving modality for patients with cardiopulmonary failure. Vascular complications, including clinically significant limb ischemia, may occur as a result of femoral artery cannulation for venoarterial (VA) ECMO. This study examines our institutional experience with femoral VA ECMO and the development of ipsilateral limb ischemia. METHODS: We performed a retrospective review of all consecutive patients undergoing femoral VA ECMO between 2011 and 2016. The primary endpoint was clinical evidence of limb-threatening ischemia. Multivariate logistic regression analysis was used to identify predictors for limb ischemia after cannulation. RESULTS: Between March 2011 and September 2016, 154 patients underwent femoral cannulation for VA ECMO. Overall in-hospital mortality was 59.7%. Clinically significant ipsilateral limb ischemia occurred in 34 (22%) patients; 7 required four-compartment fasciotomy, and 3 of these patients required amputation. On univariate analysis, a history of pulmonary disease, peripheral arterial disease, and stroke or transient ischemic attack was significantly associated with clinical limb ischemia. On multivariate analysis, younger age (odds ratio [OR], 0.96; 95% confidence interval [CI], 0.93-0.99), diabetes (OR, 2.77; 95% CI, 1.08-7.12), pulmonary disease (OR, 3.86; 95% CI, 1.38-10.78), and peripheral arterial disease (OR, 13.68; CI, 2.75-68.01) were associated with limb ischemia. Lack of prophylactic distal perfusion catheter and arterial cannula size were not independently associated with limb ischemia. CONCLUSIONS: Femoral ECMO cannulation can be associated with significant limb ischemia necessitating surgical intervention. Younger patients, as well as those with a history of diabetes, pulmonary disease, and peripheral arterial disease, may be at increased risk for this complication.

Risk factors for unplanned readmission and stump complications after major lower extremity amputation.

OBJECTIVE: The unplanned 30-day readmission rate is a marker of quality of patient care across many disciplines. Data regarding risk factors for unplanned readmission after major lower extremity amputation (LEA) are limited. We evaluated predictors of readmission at our institution after major LEA. METHODS: We conducted a retrospective review of all patients undergoing above-knee amputation (AKA) or below-knee amputation (BKA) between November 2009 and November 2014. Patient demographic variables were collected. Predictors of unplanned 30-day readmission and stump complications were determined by multivariable logistic regression. RESULTS: A total of 811 patients were identified (AKA, 325; BKA, 486). Of these, 739 patients were included in the final analysis after excluding 30-day decedents without readmission. The overall 30-day readmission rate was 28.8% (AKA 27.9%; BKA 29.4%; P = .730). Stump complications accounted for 28.6% of readmissions (16.5% of AKA; 35.8% of BKA; P = .004). Other common diagnoses included nonsurgical site infection (33.8%), exacerbation of congestive heart failure (7.0%), and diabetes-related complications (6.1%). Surgical intervention was performed on 61% of stump complications (35.9% of AKA readmitted with stump complications; 68.7% of BKA readmitted with stump complications). BKA stump complications were converted to AKAs in 34.1% of cases (3.2% of the total BKA). None of the AKA stump complications required a higher level of amputation (ie, hip disarticulation). Independent predictors of all 30-day readmission included coronary artery disease and end-stage renal disease. American Society of Anesthesiologists class 3 as compared with class 4 was protective. Independent predictors of 30-day readmission for stump complications included rest pain and BKA. Patients who underwent BKA, rest pain as an indication for amputation, and having an occluded bypass graft were predictors of having a stump complication requiring surgery. CONCLUSIONS: The 30-day readmission rate after major LEA is high, with wound infections accounting for a significant proportion of these readmissions. There was no difference in readmission rates based on level of amputation. Those undergoing BKA were more likely to present with stump complications requiring a surgical intervention, and often a higher level of amputation. Identification of high-risk patients may play a role in reducing postoperative readmissions and stump complications.

Statin use and other factors associated with mortality after major lower extremity amputation.

OBJECTIVE: Above-knee amputations (AKAs) and below-knee amputations (BKAs) are associated with high postoperative mortality rates. In this study, we examined factors associated with 30-day, 90-day, and 1-year mortality in patients who underwent a major lower extremity amputation. METHODS: We queried a prospectively collected institutional database for all patients who underwent AKA or BKA with primary or secondary closure, during a 5-year period, between November 2009 and November 2014. Predictors of 30- and 90-day mortality were determined by multivariable logistic regression, and risk indexes for 1-year mortality were determined with Cox proportional hazards model. RESULTS: We identified 811 patients who underwent AKA (n = 325) or BKA (n = 486). The 30-day mortality was 8.4% (AKA, 13.5%; BKA, 4.9%; P < .001) and 90-day mortality was 15.4% (AKA, 24.3%; BKA, 9.45%; P < .001). Predictors of 30-day mortality included AKA (odds ratio [OR], 3.09; 95% confidence interval [CI], 1.76-5.53), emergency operation (OR, 2.86; 95% CI, 1.56-5.14), chronic obstructive pulmonary disease (OR, 3.09; 95% CI, 1.07-7.81), end-stage renal disease (ESRD) on hemodialysis (HD; OR, 2.35; 95% CI, 1.24-4.33), and chronic kidney disease stages 3 (OR, 1.84; 95% CI, 1.00-3.37) and 4 (OR, 2.33; 95% CI, 1.01-4.98). Predictors of 90-day mortality included age (OR, 1.02; 95% CI, 1.00-1.04), ESRD on HD (OR, 2.56; 95% CI, 1.55-4.22), AKA (OR, 2.61; 95% CI, 1.70-4.05), history of coronary artery bypass grafting (OR, 2.04; 95% CI, 1.06-3.87), and medium-intensity or high-intensity statin (OR, 0.46; 95% CI, 0.29-0.73). One-year survival for the overall cohort was 73.7% (95% CI, 70.8%-76.8%). Predictors of 1-year mortality included AKA (hazard ratio [HR], 2.07; 95% CI, 1.54-2.77), coronary artery bypass grafting (HR, 1.57; 95% CI, 1.07-2.32), age >70 years (HR, 1.39; 95% CI, 1.02-1.88), gangrene (HR, 1.44; 95% CI, 1.07-1.94), ESRD on HD (HR, 1.96; 95% CI, 1.42-2.70), chronic obstructive pulmonary disease (HR, 2.54; 95% CI, 1.52-4.25), Caucasian race (HR, 1.62; 95% CI, 1.18-2.22), history of open lower extremity revascularization (HR, 0.71; 95% CI, 0.51-1.00) and undergoing bilateral amputations (HR, 2.10; 95% CI, 1.06-4.15). In the year after amputation, medium-intensity statin (HR, 0.64; 95% CI, 0.47-0.87) and high-intensity statin (HR, 0.56; 95% CI, 0.33-0.95) conferred a mortality benefit. Low-intensity statins did not confer protection from mortality. At 1 year after amputation, only 44.7% of patients were receiving appropriate statin therapy. CONCLUSIONS: AKA and BKA have historically been associated with high mortality rates. Medium-intensity and high-intensity statin therapies were associated with a mortality benefit at 1 year. We have identified initiation of statin therapy in this high-risk population as a gap in patient care.

Carotid Reconstruction with Bovine Carotid Heterograft after En Bloc Resection of Squamous Cell Carcinoma with Direct Internal Carotid Invasion.

We report a novel use of Artegraft (North Brunswick, NJ) bovine heterograft for carotid reconstruction after resection of a neck squamous cell carcinoma (SCC). A 65-year-old man presented with a large left neck SCC encasing and invading the cervical internal carotid artery (ICA). Computed tomography angiography revealed an incomplete Circle of Willis, and no viable vein conduit on duplex mapping. The patient underwent en bloc resection including portion of the cervical ICA followed by reconstruction with Artegraft which was well tolerated. This represents the first case report of tumor invasion of the ICA reconstructed using Artegraft as conduit.

Strategies for Hemodialysis Access: A Vascular Surgeon's Perspective.

Problems related to hemodialysis access are a significant cause of morbidity and mortality in patients with end-stage renal disease. Physicians of all specialties who are involved in the placement and maintenance of vascular access for hemodialysis must have a long-term strategy for sequential placement of autogenous fistulas, transpositions, and prosthetic grafts to preserve access sites and to avoid long-term use of tunneled dialysis catheters. The Fistula First and KDOQI initiatives have provided strategies and algorithms for access placement in patients with chronic kidney disease. Preservation of veins should begin before dialysis access is necessary to achieve the goal of creating a primary arteriovenous (AV) fistula or transposition suitable for cannulation when dialysis is initiated. Prosthetic and biologic grafts offer reasonable alternatives when autogenous access is not feasible. Newer graft materials and conduits are under evaluation to improve long-term outcomes. Use of tunneled dialysis catheters should be discouraged and they should be considered a last resort for long-term access. We present a strategy from the perspective of a vascular surgeon for the sequential placement of AV fistulas, venous transpositions, and AV grafts in these challenging patients. We also discuss specific concerns regarding hemodialysis access in difficult patient populations such as the elderly patient and the morbidly obese patient.

Bilateral intracranial electrodes for lateralizing intractable epilepsy: efficacy, risk, and outcome.

OBJECTIVE: Medically refractory epilepsy is amenable to neurosurgical intervention if the epileptogenic focus is accurately localized. If the scalp video-electroencephalography (EEG) and magnetic resonance imaging are nonlateralizing, yet a single focus is suspected, video-EEG monitoring with bilateral intracranial electrode placement is helpful to lateralize the ictal onset zone. We describe the indications, risks, and utility of such bilateral surveys at our institution. METHODS: We retrospectively reviewed 26 patients with medically refractory seizures who were treated over a 5-year period and underwent bilateral placement of intracranial electrodes. Subdural strips were used in all cases, and additional stereotactic implantation of depth electrodes into mesial temporal lobes occurred in 50%. The mean patient age was 37.7 years, and 65.4% of patients were male. RESULTS: The most common indication for bilateral invasive monitoring was bilateral ictal onsets on surface video-EEG (76.9%), followed by frequent interictal spikes contralateral to a single ictal focus (7.7%). Intracranial monitoring lasted an average of 8.2 days, with ictal events recorded in all cases. Ten patients (38.5%) subsequently underwent more extensive unilateral monitoring via implantation of subdural and depth electrodes through a craniotomy. A therapeutic procedure was performed in 17 patients (65.4%), whereas 1 patient underwent a palliative corpus callosotomy (3.8%). Nine patients underwent a resection without unilateral invasive mapping. Reasons for no therapeutic surgery (n = 8) included multifocal onsets, failing the Wada test, refusal of further treatment, and negative intraoperative electrocorticogram. There was 1 surgical complication, involving a retained electrode fragment that was removed in a separate minor procedure. Of the 26 patients, 15 (57.7%) are now seizure-free or have seizure disorders that have substantially improved (modified Engel classes I and II). Of the 17 patients who underwent a potentially curative surgery, 13 (76.5%) were Engel classes I and II. CONCLUSION: Bilateral placement of subdural strip and depth electrodes for epilepsy monitoring in patients with nonlateralizing scalp EEG and/or discordant imaging studies but clinical suspicion for focal seizure origin is both safe and effective. Given the safety and efficacy of this procedure, epileptologists should have a low threshold to consider bilateral implants for suitable patients.

Recent developments in oximetry and perfusion-based mapping techniques and their role in the surgical treatment of neocortical epilepsy.

Detailed understanding of neurovascular coupling during epilepsy is critical for the interpretation of various perfusion-based imaging techniques, such as positron emission tomography, single-photon-emission computed tomography, and functional magnetic resonance imaging, which are used to guide surgical therapy. We used high-resolution intrinsic signal- and voltage-sensitive dye imaging, as well as oxygen-sensitive electrodes, to map the precise spatiotemporal relationship between excitatory and inhibitory neuronal activity, cerebral blood volume, and oximetry during epilepsy. We observed a rapid focal decrease in tissue oxygenation and an increase in deoxygenated hemoglobin in association with both interictal and ictal events. This "epileptic dip" in oxygenation lasts several seconds following both interictal and ictal events, implying that for a period, cerebral blood flow is inadequate to meet metabolic demand. We also observed a rapid focal increase in cerebral blood volume that soon spread to adjacent nonepileptic gyri. Likewise, a diffuse decrease in deoxygenated hemoglobin, related to the blood oxygen level-dependent signal recorded with functional magnetic resonance imaging, spread to adjacent gyri and was poorly localized.

TorsinA and heat shock proteins act as molecular chaperones: suppression of alpha-synuclein aggregation.

TorsinA, a protein with homology to yeast heat shock protein104, has previously been demonstrated to colocalize with alpha-synuclein in Lewy bodies, the pathological hallmark of Parkinson's disease. Heat shock proteins are a family of chaperones that are both constitutively expressed and induced by stressors, and that serve essential functions for protein refolding and/or degradation. Here, we demonstrate that, like torsinA, specific molecular chaperone heat shock proteins colocalize with alpha-synuclein in Lewy bodies. In addition, using a cellular model of alpha-synuclein aggregation, we demonstrate that torsinA and specific heat shock protein molecular chaperones colocalize with alpha-synuclein immunopositive inclusions. Further, overexpression of torsinA and specific heat shock proteins suppress alpha-synuclein aggregation in this cellular model, whereas mutant torsinA has no effect. These data suggest that torsinA has chaperone-like activity and that the disease-associated GAG deletion mutant has a loss-of-function phenotype. Moreover, these data support a role for chaperone proteins, including torsinA and heat shock proteins, in cellular responses to neurodegenerative inclusions.