David L. Cull

Bariatric Surgery Is Associated with a Reduction in Major Macrovascular and Microvascular Complications in Moderately to Severely Obese Patients with Type 2 Diabetes Mellitus

BACKGROUNDnBariatric surgery (BAR) has been established as an effective treatment for type 2 diabetes mellitus (T2DM) in obese patients. However, few studies have examined the mid- to long-term outcomes of bariatric surgery in diabetic populations. Specifically, no comparative studies have broadly examined major macrovascular and microvascular complications in bariatric surgical patients vs similar, nonbariatric surgery controls.nnnSTUDY DESIGNnWe conducted a large, population-based, retrospective cohort study of adult obese patients with T2DM, from 1996 to 2009, using UB-04 administrative data and vital records. Eligible patients undergoing bariatric surgery (BAR [n = 2,580]) were compared with nonbariatric surgery controls (CON [n = 13,371]) for the outcomes of any first major macrovascular event (myocardial infarction, stroke, or all-cause death) or microvascular event (new diagnosis of blindness, laser eye or retinal surgery, nontraumatic amputation, or creation of permanent arteriovenous access for hemodialysis), assessed in combination and separately, as well as other vascular events (carotid, coronary or lower extremity revascularization or new diagnosis of congestive heart failure or angina pectoris).nnnRESULTSnBariatric surgery was associated with favorable unadjusted 5-year event-free survival estimates for the combined primary outcome (95% ± 1% vs 81% ± 1%, log-rank p < 0.01) and each secondary outcome (log-rank p < 0.01). Multivariate-adjusted and propensity-based relative risk estimates showed BAR to be associated with a 60% to 70% reduction (adjusted hazard ratio [HR] 0.36, 95% CI 0.27 to 0.47) in the combined primary outcome and 60% to 80% risk reductions for each secondary outcome (macrovascular events [adjusted HR 0.39, 95% CI 0.29 to 0.51]; microvascular events [adjusted HR 0.22, 95% CI 0.09 to 0.49]; and other vascular events [adjusted HR 0.25, 95% CI 0.19 to 0.32]).nnnCONCLUSIONSnBariatric surgery is associated with a 65% reduction in major macrovascular and microvascular events in moderately and severely obese patients with T2DM.

Comparison of Interventional Outcomes According to Preoperative Indication: A Single Center Analysis of 2,240 Limb Revascularizations

BACKGROUNDnOutcomes after lower extremity revascularization are usually reported according to the level of peripheral arterial disease (PAD, aortoiliac or infrainguinal) or the method of treatment (open or endovascular surgery). Outcomes stratified by indication, ie, claudication or critical limb ischemia (rest pain and tissue loss), have not been well studied. The purpose of this study was to compare postoperative outcomes according to the preoperative indications.nnnSTUDY DESIGNnOutcomes of 2,240 consecutive limb revascularizations in 1,732 patients from January 1998 through December 2005 were stratified and examined according to preoperative indication: claudication (n=999 limbs), ischemic rest pain (n=464 limbs), or tissue loss (n=777 limbs). End points measured included primary and secondary interventional or operative patency, limb salvage, survival, amputation-free survival, maintenance of ambulation, maintenance of independence, and resolution of presenting symptoms.nnnRESULTSnThe proportion of medical comorbidities and the severity of disease increased significantly by cohort from claudication to rest pain to tissue loss. With a mean followup of 1,089 days (range 0 to 3,689 days), overall outcomes performance declined consistently according to indication for all end points measured at 5 years (claudication, rest pain, tissue loss, p value): secondary reconstruction patency (93%, 80%, 66%, respectively; p < 0.001), limb salvage (99%, 81%, 68%, respectively; p < 0.001), survival (78%, 46%, 30%, respectively; p < 0.001), amputation-free survival (78%, 42%, 25%, respectively; p < 0.001), maintenance of ambulation (96%, 78%, 68%, respectively; p < 0.001), maintenance of independence (98%, 85%, 75%, respectively; p < 0.001), and resolution of presenting symptoms (79%, 61%, 42%, respectively; p < 0.001).nnnCONCLUSIONSnThere is a declining spectrum of outcomes performance from claudication to rest pain to tissue loss. These findings question the accuracy of all previously published data for critical limb ischemia, for which rest pain and tissue loss are usually blended and reported as a single outcomes value.

An early validation of the Society for Vascular Surgery Lower Extremity Threatened Limb Classification System

OBJECTIVEnThe 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.nnnMETHODSnBetween 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.nnnRESULTSnOf 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.nnnCONCLUSIONSnThe 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.

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

INTRODUCTIONnSuccessful 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.nnnMETHODSnBetween 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.nnnRESULTSnOverall 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).nnnCONCLUSIONnClinical 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.

Open versus endovascular intervention for critical limb ischemia: a population-based study.

BACKGROUNDnEndovascular techniques are considered by many as the first-line treatment for critical limb ischemia (CLI). The purpose of this study is to assess the impact of endovascular therapy on CLI and amputation in South Carolina during the past decade.nnnSTUDY DESIGNnThis is a retrospective, comparative analysis of treatment outcomes for CLI in the pre-endovascular era and the endovascular era. The South Carolina Office of Research and Statistics database was reviewed using ICD-9 diagnosis and procedure codes to identify patients who underwent limb revascularization in 1996 (pre-endovascular era) and 2005 (endovascular era) for CLI and to determine those who required subsequent limb amputation and additional revascularization.nnnRESULTSnThe index limb revascularization procedures increased 33% from 571 in 1996 (420 [74%] open; 151 [26%] endovascular) to 758 in 2005 (373 [49%] open; 385 [51%] endovascular). The demographics and comorbidities for patients who underwent revascularization in 1996 were similar to those in 2005. The amputation rate for patients who underwent a revascularization procedure was 34% at 1 year and 43% at 3 years in 1996, compared with 34% at 1 year and 40% at 3 years in 2005 (p = NS). The percentage of patients who required an additional revascularization in the same calendar year increased from 8% in 1996 to 19% in 2005 (p < 0.001).nnnCONCLUSIONSnAlthough there has been an absolute increase in the number of revascularization procedures for CLI, with a clear shift toward endovascular therapy, the amputation rates for these patients have not changed. However, the shift to endovascular interventions has increased the number of secondary procedures required to maintain limb-salvage rates equivalent to those of the pre-endovascular era.

Comparison of Arteriovenous Fistulas and Arteriovenous Grafts in Patients with Favorable Vascular Anatomy and Equivalent Access to Health Care: Is a Reappraisal of the Fistula First Initiative Indicated?

BACKGROUNDnInitiatives to increase arteriovenous fistula (AVF) use are based on studies that show that AVFs require fewer interventions and have better patency than arteriovenous grafts (AVGs). Because patients who receive AVFs typically have more favorable vascular anatomy and are referred earlier for access placement than those who receive AVGs, the advantages of AVF might be overestimated. We compared outcomes for AVFs and AVGs in patients with equivalent vascular anatomy who were on dialysis via catheter at the time of vascular access placement.nnnSTUDY DESIGNnThe study included patients who underwent placement of a first-time AVF or AVG between 2006 and 2009, who were on dialysis via catheter at the time of access placement, and who had favorable arterial and venous (>3 mm) anatomy. Outcomes for AVF and AVG were compared.nnnRESULTSnEighty-nine AVF and 59 AVG patients met study inclusion criteria. Similar secondary patency was achieved by AVG and AVF at 12 (72% vs 71%) and 24 months (57% vs 62%), respectively (p = 0.96). The number of interventions required to maintain patency for AVF (n = 1; range 0 to 10) and AVG (n = 1; range 0 to 11) were not different (p = 0.36). However, the number of catheter days to first access use was more than doubled in the AVF group (median 81 days) compared with the AVG group (median 38 days; p < 0.001).nnnCONCLUSIONSnFor patients who are receiving dialysis via catheter at the time of access placement, the maturation time, risk of nonmaturation, and interventions required to achieve a functional AVF can negate its benefits over AVG. A fistula first approach might not always apply to patients who are already on dialysis when referred for chronic access placement.

Outcome of the Use of Stent Grafts to Salvage Failed Arteriovenous Accesses

BACKGROUNDnSince elements of the Dialysis Outcome Quality Initiative (K/DOQI) were implemented a decade ago, there has been a reduction in mortality for patients on hemodialysis. As patient longevity has increased, AV access site preservation by salvaging failed arteriovenous (AV) accesses has become increasingly important. However, efforts to salvage an AV access must be balanced against futile and expensive procedures. The Viabahn Endoprosthesis is a self-expandable stent graft (SG) that can be used to treat vein rupture or fibrotic lesions with significant elastic recoil following balloon angioplasty. The literature comprising the outcome of the use of SGs in salvaging failed AV accesses is limited. The purpose of this study is to determine the outcome of failed AV accesses treated with SGs and to identify patient or graft factors predictive of success.nnnMETHODSnThe vascular access database and office, hospital, and dialysis unit records were retrospectively reviewed to identify all patients who underwent placement of an SG for the treatment of a thrombosed AV access between September 2004 and December 2007. Mean patient follow-up was 6 months. The K/DOQI goal for patency following a surgical intervention (6 months or later) was used to determine procedure success or failure. Kaplan-Meier life-table analysis was used to determine patency. Patient demographics and graft factors (location, diameter, length) were analyzed to identify predictors of success.nnnRESULTSnFifty-five SGs were placed in 48 patients (males, 29%; mean age, 61 years; diabetes mellitus, 47%) with a failed AV access. The indications were to treat significant elastic recoil or vein rupture following balloon angioplasty (47 patients) and to treat an AV graft seroma (1 patient). Cost for the VE ranged from

Radiation safety education in vascular surgery training

2337 to

Description and outcomes of a simple surgical technique to treat thrombosed autogenous accesses

3367 per patient. The procedure was deemed successful (patent at 6 months) in 29 + or - 7% of cases. Procedure success was not influenced by AV access location, endoprosthesis size (diameter or length), or patient demographic factors (p > 0.05).nnnCONCLUSIONnUse of the SG to salvage AV accesses falls short of the current K/DOQI clinical outcome goals for successful surgical intervention in the majority of cases. Given these results and the cost of the SG, its use is indicated in cases where AV access salvage will have an impact on long-term survival such as for patients in whom there are few options for new access placement. Further studies are needed to compare the SG to less costly options, such as angioplasty alone or angioplasty with the use of bare metal stents.

Establishing patient-specific criteria for selecting the optimal upper extremity vascular access procedure.

OBJECTIVEnEndovascular volume during vascular surgery training has increased profoundly over recent decades, providing heavy exposure to ionizing radiation. The study purpose was to examine the radiation safety training and practices of current vascular surgery trainees.nnnMETHODSnAn anonymous survey was distributed to all current U.S. trainees. Responses were compared according to the presence of formal radiation safety training and also the trainees perception of their attendings adherence to As Low As Reasonably Achievable (ALARA) strategies.nnnRESULTSnThe response rate was 14%. Forty-five percent had no formal radiation safety training, 74% were unaware of the radiation safety policy for pregnant females, 48% did not know their radiation safety officers contact information, and 43% were unaware of the yearly acceptable levels of radiation exposure. Trained residents knew more basic radiation safety information, and more likely wore their dosimeter badges (P < .05). Trained residents found their radiation safety officer helpful in developing safety habits; untrained residents relied on other residents (P < .05). Trainees who felt their attendings consistently practiced ALARA strategies more likely practiced ALARA themselves (P < .05).nnnCONCLUSIONSnThe lack of formal radiation safety training in respondents may reflect an inadequate state of radiation safety education and practices among U.S. vascular surgery residents.