Trends, complications, and mortality in peripheral vascular surgery

Beta-adrenergic blockers for perioperative cardiac risk reduction in people undergoing vascular surgery

BACKGROUND

People undergoing major vascular surgery have an increased risk of postoperative cardiac complications. Beta-adrenergic blockers represent an important and established pharmacological intervention in the prevention of cardiac complications in people with coronary artery disease. It has been proposed that this class of drugs may reduce the risk of perioperative cardiac complications in people undergoing major non-cardiac vascular surgery.

OBJECTIVES

To review the efficacy and safety of perioperative beta-adrenergic blockade in reducing cardiac or all-cause mortality, myocardial infarction, and other cardiovascular safety outcomes in people undergoing major non-cardiac vascular surgery.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (January 2014) and the Cochrane Central Register of Controlled Trials (CENTRAL; 2013, Issue 12). We searched trials databases and checked reference lists of relevant articles.

SELECTION CRITERIA

We included prospective, randomised controlled trials of perioperative beta-adrenergic blockade of people over 18 years of age undergoing non-cardiac vascular surgery.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection and data extraction. We resolved disagreements through discussion. We performed meta-analysis using a fixed-effect model with odds ratios (ORs) and 95% confidence intervals (CIs).

MAIN RESULTS

We included two studies in this review, both of which were double-blind, randomised controlled trials comparing perioperative beta-adrenergic blockade (metoprolol) with placebo, on cardiovascular outcomes in people undergoing major non-cardiac vascular surgery. We included 599 participants receiving beta-adrenergic blockers (301 participants) or placebo (298 participants). The overall quality of studies was good. However, one study did not report random sequence generation or allocation concealment techniques, indicating possible selection bias, and the other study did not report outcome assessor blinding and was possibly underpowered. It should be noted that several of the outcomes were only reported in a single study and neither of the studies reported on vascular patency/graft occlusion, which reduces the quality of evidence to moderate. There was no evidence that perioperative beta-adrenergic blockade reduced all-cause mortality (OR 0.62, 95% CI 0.03 to 15.02), cardiovascular mortality (OR 0.34, 95% CI 0.01 to 8.32), non-fatal myocardial infarction (OR 0.83, 95% CI 0.46 to 1.49; P value = 0.53), arrhythmia (OR 0.70, 95% CI 0.26 to 1.88), heart failure (OR 1.71, 95% CI 0.40 to 7.23), stroke (OR 2.67, 95% CI 0.11 to 67.08), composite cardiovascular events (OR 0.87, 95% CI 0.55 to 1.39; P value = 0.57) or re-hospitalisation at 30 days (OR 0.86, 95% CI 0.48 to 1.52). However, there was strong evidence that beta-adrenergic blockers increased the odds of intra-operative bradycardia (OR 4.97, 95% CI 3.22 to 7.65; P value < 0.00001) and intra-operative hypotension (OR 1.84, 95% CI 1.31 to 2.59; P value = 0.0005).

AUTHORS' CONCLUSIONS

This meta-analysis currently offers no clear evidence that perioperative beta-adrenergic blockade reduces postoperative cardiac morbidity and mortality in people undergoing major non-cardiac vascular surgery. There is evidence that intra-operative bradycardia and hypotension are more likely in people taking perioperative beta-adrenergic blockers, which should be weighed with any benefit.

Trend, Risk Factors, and Costs of Clostridium difficile Infections in Vascular Surgery

BACKGROUND

Starting in December 2013, the Hospital Inpatient Quality Reporting Program included Clostridium difficile infection (CDI) rates as a new publically reported quality measure. Our goal was to review the trend, hospital variability in CDI rates, and associated risk factors and costs in vascular surgery.

METHODS

The rates of CDI after major vascular procedures including aortic abdominal aneurysm (AAA) repair, carotid endarterectomy or stenting, lower extremity revascularization (LER), and LE amputation were identified using Nationwide Inpatient Sample database for 2000-2011. Risk factors associated with CDI were analyzed with hierarchical multivariate logistic regression. Extra costs, length of stay (LOS), and mortality were assessed for propensity-matched hospitalizations with and without CDI.

RESULTS

During the study period, the rates of CDI after vascular procedures had increased by 74% from 0.6 in 2000 to 1.05% in 2011, whereas the case fatality rate was stable at 9-11%. In 2011, the highest rates were after ruptured aortic abdominal aneurysm (rAAA) repair (3.3%), followed by lower extremity amputations (2.3%) and elective open AAA (1.3%). The rates of CDI increased after all vascular procedures during the 12 years. The highest increase was after endovascular LER (151.8%) and open rAAA repair (135.7%). In 2011, patients who had experienced CDI had median LOS of 15 days (interquartile range, 9-25 days) compared with 8.3 days for matched patients without CDI, in-hospital mortality 9.1% (compared with 5.0%), and $13,471 extra cost per hospitalization. The estimated cost associated with CDI in vascular surgery in the United States was ∼$98 million in 2011. Hospital rates of CDI varied from 0 to 50% with 3.5% of hospitals having infection rates ≥5%. Factors associated with CDI included multiple chronic conditions, female gender, surgery type, emergent and weekend hospitalizations, hospital transfers, and urban locations.

CONCLUSIONS

Despite potential reduction of infection rates as evidenced by the experience of hospitals with effective interventions, CDI is increasing among vascular surgery patients. It is associated with prolonged LOS, increased mortality, and higher costs.

Contemporary treatment for critical ischemia: the evidence for interventional radiology or surgery

This article is a review of the evidence regarding the management of patients with critical limb ischemia. The aim of the study is to discuss the definition, incidence, and clinical importance of critical limb ischemia, as well as the aims of treatment in terms of quality of life and limb salvage. Endovascular and surgical treatments should not be viewed as competing therapies. In fact, these are complementary techniques each with strengths and weaknesses. The authors will propose a strategy based on the available evidence for deciding the optimal approach to management of patients with critical limb ischemia.

The in vivo characterization of electrospun heparin-bonded polycaprolactone in small-diameter vascular reconstruction

Objective

To evaluate the possibility of using heparin-bonded polycaprolactone grafts to replace small-diameter arteries.

Methods

Polycaprolactone was bonded with heparin. The activated partial thromboplastin time of heparin-bonded polycaprolactone grafts was determined in vitro. Small-diameter grafts were electrospun with heparin-bonded polycaprolactone and polycaprolactone and were implanted in dogs to substitute part of the femoral artery. Angiography was used to investigate the patency and aneurysm of the grafts after transplantation. After angiography, the patent grafts were explanted for histology analysis. The degradation of the grafts and the collagen content of the grafts were measured.

Results

Activated partial thromboplastin time tests in vitro showed that heparin-bonded polycaprolactone grafts exhibit obvious anticoagulation. Arteriography showed that two heparin-bonded polycaprolactone and three polycaprolactone grafts were obstructed. Other grafts were patent, without aneurysm formation. Histological analysis showed that the tested grafts degraded evidently over the implantation time and that the luminal surface of the tested grafts had become covered by endothelial cells. Collagen deposition in heparin-bonded polycaprolactone increased with time. There were no calcifications in the grafts. Gel permeation chromatography showed the heparin-bonded polycaprolactone explants at 12 weeks lose about 32% for Mw and 24% for Mn. The collagen content on the heparin-bonded polycaprolactone grafts increased over time.

Conclusion

This preliminary study demonstrates that heparin-bonded polycaprolactone is a suitable graft for small artery reconstruction. However, heparin-bonded polycaprolactone degrades more rapidly than polycaprolactone in vivo.

4-French-compatible endovascular material is safe and effective in the treatment of femoropopliteal occlusive disease: results of the 4-EVER trial

PURPOSE

To report the 1-year results of a prospective multicenter trial to evaluate the safety and efficacy of treating symptomatic femoropopliteal occlusive disease using 4-F-compatible materials and no closure device.

METHODS

The non-randomized 4-EVER trial (4-F endovascular treatment approach to infrainguinal disease) was conducted at 5 European hospitals (ClinicalTrials.gov identifier NCT01413139). The protocol mandated the use of only 4-F sheaths, self-expanding nitinol stents (Astron Pulsar or Pulsar-18 stent), and balloons from a single manufacturer. Between June 2010 and June 2011, 120 symptomatic patients (82 men; mean age 71±9.7 years, range 47-90), primarily claudicants, treated for 120 femoropopliteal lesions (>90% TASC A/B) were enrolled. The mean lesion length was 71.0±45.9 mm. Follow-up evaluations were scheduled on day 1 and at 1, 6, 12, and 24 months. A duplex ultrasound was performed on all follow-up visits to determine vessel patency (primary outcome measure at 1 year), and biplanar radiography was performed at 12 and 24 months to assess stent fracture.

RESULTS

Stents were successfully implanted in all patients: an Astron Pulsar stent in 70 (58.3%) lesions and a Pulsar-18 stent in 46 (38.3%); 4 (3.3%) patients had both stents implanted for flow-limiting dissection after predilation. No closure devices were used; the mean manual compression time was 8.1 minutes (2-15). Four (3.3%) patients developed significant hematoma at the puncture site, but none required surgical repair. The overall 12-month primary patency rate was 81.4%: 85.2% for the Astron Pulsar and 73.4% for the Pulsar-18 (p=0.236). Freedom from target lesion revascularization at 12 months for the entire cohort was 89.3%.

CONCLUSION

Compared to published historical data for superficial femoral artery type A/B lesion stenting using 6-F devices, the 4-F devices applied in this trial showed similar patency at 12 months, fewer access site complications, and shorter manual compression times, supporting the supposition that 4-F endovascular treatment is safe and effective.

Chronic kidney disease predicts long-term mortality after major lower extremity amputation

Background:

Despite low peri-operative mortality after major lower extremity amputation, long-term mortality remains substantial. Metabolic syndrome is increasing in incidence and prevalence at an alarming rate in the USA.

Aim:

This study was to determine whether metabolic syndrome predicts outcome after major lower extremity amputation.

Patients and Methods:

A retrospective review of charts between July 2005 and June 2010.

Results:

Fifty-four patients underwent a total of 60 major lower extremity amputations. Sixty percent underwent below-knee amputation and 40% underwent above-knee amputation. The 30-day mortality was 7% with no difference in level (below-knee amputation, 8%; above-knee amputation, 4%; P = 0.53). The mean follow-up time was 39.7 months. The 5-year survival was 54% in the whole group, and was independent of level of amputation (P = 0.24) or urgency of the procedure (P = 0.51). Survival was significantly decreased by the presence of underlying chronic kidney disease (P = 0.04) but not by other comorbidities (history of myocardial infarction, P = 0.79; metabolic syndrome, P = 0.64; diabetes mellitus, P = 0.56).

Conclusion:

Metabolic syndrome is not associated with increased risk of adverse outcomes after lower extremity amputation. However, patients with chronic kidney disease constitute a sub-group of patients at higher risk of postoperative long-term mortality and may be a group to target for intervention.

Postoperative ICU management of vascular surgery patients

Critical care management of vascular surgical patients poses significant challenges owing to patients' comorbidities and the magnitude of the surgical procedures. The primary goals of the anesthesiologist and intensivist are reestablishing preoperative homeostasis, optimizing hemodynamics until return of normal organ function, and managing postoperative complications promptly and effectively. Postoperative critical care management demands a detailed knowledge of the various vascular surgical procedures and the potential postoperative complications. In this review, the authors describe the postoperative complications related to the major specific vascular surgical procedures and their perioperative management.

Fenestrated endovascular repair of complex aortic aneurysms

BACKGROUND

Fenestrated endovascular aneurysm repair (FEVAR) provides an endovascular solution for patients with large abdominal aortic aneurysms and challenging neck anatomy in addition to repair of endoleaks and pseudoaneurysms. This article reports the midterm outcomes of FEVAR from a single-tertiary referral centre in Ireland.

METHODS

From 2006 to 2012, nine consecutive asymptomatic patients with neck anatomy unfavourable for standard EVAR underwent endovascular repair with a customised fenestrated Zenith stent graft. An additional three patients had fenestrated grafts for repair of pseudoaneurysms (n = 2) following open AAA repair and a type I endoleak (n = 1). All patients were prospectively enrolled in a computerised database. Outcomes including mortality, morbidity, renal function, target vessel patency, endoleak and reintervention were analysed.

FINDINGS

The mean age and aneurysm size in the primary repair group were 74 years (65-84 years) and 6 cm (5-8.3 cm), respectively, and in the secondary repair group, the mean age was 66 years (61-75 years). No procedures required open conversion, and no visceral arteries were lost. On completion angiography, two patients in group 1 had a type I endoleak and one had a type III endoleak. There were no endoleaks in the secondary repair group. Follow-up ranged from 30 days to 6 years. There was one death within 30 days (8 %) and two deaths at 3 years from non-aneurysm-related causes. Six patients required secondary interventions. Three patients had a transient post-operative creatinine rise of >30 %.

CONCLUSION

Our study supports FEVAR as a feasible and effective therapy in the management of patients with complex aortic aneurysms.

Endovascular treatment of abdominal aortic aneurysms

Patients with abdominal aortic aneurysms (AAAs) are usually treated with endovascular aneurysm repair (EVAR), which has become the standard of care in many hospitals for patients with suitable anatomy. Clinical evidence indicates that EVAR is associated with superior perioperative outcomes and similar long-term survival compared with open repair. Since the randomized, controlled trials that provided this evidence were conducted, however, the stent graft technology for infrarenal AAA has been further developed. Improvements include profile downsizing, optimization of sealing and fixation, and the use of low porosity fabrics. In addition, imaging techniques have improved, enabling better preoperative planning, stent graft placement, and postoperative surveillance. Also in the past few years, fenestrated and branched stent grafts have increasingly been used to manage anatomically challenging aneurysms, and experiments with off-label use of stent grafts have been performed to treat patients deemed unfit or unsuitable for other treatment strategies. Overall, the indications for endovascular management of AAA are expanding to include increasingly complex and anatomically challenging aneurysms. Ongoing studies and optimization of imaging, in addition to technological refinement of stent grafts, will hopefully continue to broaden the utilization of EVAR.

National variation in the utilization of alternative imaging in peripheral arterial disease

OBJECTIVE

The value and cost-effectiveness of less invasive alternative imaging (AI) modalities (duplex ultrasound scanning, computed tomography angiography, and magnetic resonance angiography) in the care of peripheral arterial disease (PAD) has been reported; however, there is no consensus on their role. We hypothesized that AI utilization is low compared with angiography in the United States and that patient and hospital characteristics are both associated with AI utilization.

METHODS

The Nationwide Inpatient Sample (2007-2010) was used to identify patients with an International Classification of Diseases-Ninth Edition diagnosis of claudication or critical limb ischemia (CLI) as well as PAD treatment (surgical, endovascular, or amputation). Patients with AI and those with angiography or expected angiography (endovascular procedures without imaging codes) were selected and compared. Multivariable logistic regression was performed for receiving AI stratified by claudication and CLI and adjusting for patient and hospital factors.

RESULTS

We identified 290,184 PAD patients, of whom 5702 (2.0%) received AI. Patients with AI were more likely to have diagnosis of CLI (78.8% vs 48.6%; P < .0001) and receive open revascularizations (30.4% vs 18.8%; P < .0001). Van Walraven comorbidity scores (mean [standard error] 5.85 ± 0.22 vs 4.10 ± 0.05; P < .0001) reflected a higher comorbidity burden in AI patients. In multivariable analysis for claudicant patients, AI was associated with large bed size (odds ratio [OR], 3.26, 95% confidence interval [CI], 1.16-9.18; P = .025), teaching hospitals (OR, 1.97; 95% CI, 1.10-3.52; P = .023), and renal failure (OR, 1.52; 95% CI, 1.13-2.05; P = .006). For CLI patients, AI was associated with black race (OR, 1.53; 95% CI, 1.13-2.08; P = .006) and chronic heart failure (OR, 1.29; 95% CI, 1.04-1.60; P = .021) and was negatively associated with renal failure (OR, 0.80; 95% CI, 0.67-0.95; P = .012). The Northeast and West regions were associated with higher odds of AI in claudicant patients (OR, 2.41; 95% CI, 1.23-4.75; P = .011; and OR, 2.59; 95% CI, 1.34-5.02; P = .005, respectively) and CLI patients (OR, 4.31; 95% CI, 2.20-8.36; P < .0001; and OR, 2.18; 95% CI, 1.12-4.22; P = .021, respectively). Rates of AI utilization across states were not evenly distributed but showed great variability, with ranges from 0.31% to 9.81%.

CONCLUSIONS

National utilization of AI for PAD is low and shows great variation among institutions in the United States. Patient and hospital factors are both associated with receiving AI in PAD care, and AI utilization is subject to significant regional variation. These findings suggest differences in systems of care or practice patterns and call for a clearer understanding and a more unified approach to imaging strategies in PAD care.

Growing impact of restenosis on the surgical treatment of peripheral arterial disease

Background

Patients with peripheral arterial disease often experience treatment failure from restenosis at the site of a prior peripheral endovascular intervention (PVI) or lower extremity bypass (LEB). The impact of these treatment failures on the utilization and outcomes of secondary interventions is poorly understood.

Methods and Results

In our regional vascular quality improvement collaborative, we compared 2350 patients undergoing primary infrainguinal LEB with 1154 patients undergoing secondary infrainguinal LEB (LEB performed after previous revascularization in the index limb) between 2003 and 2011. The proportion of patients undergoing secondary LEB increased by 72% during the study period (22% of all LEBs in 2003 to 38% in 2011, P<0.001). In‐hospital outcomes, such as myocardial infarction, death, and amputation, were similar between primary and secondary LEB groups. However, in both crude and propensity‐weighted analyses, secondary LEB was associated with significantly inferior 1‐year outcomes, including major adverse limb event‐free survival (composite of death, new bypass graft, surgical bypass graft revision, thrombectomy/thrombolysis, or above‐ankle amputation; Secondary LEB MALE‐free survival = 61.6% vs primary LEB MALE‐free survival = 67.5%, P=0.002) and reintervention or amputation‐free survival (composite of death, reintervention, or above‐ankle amputation; Secondary LEB RAO‐free survival = 58.9% vs Primary LEB RAO‐free survival 64.1%, P=0.003). Inferior outcomes for secondary LEB were observed regardless of the prior failed treatment type (PVI or LEB).

Conclusions

In an era of increasing utilization of PVI, a growing proportion of patients undergo LEB in the setting of a prior failed PVI or surgical bypass. When caring for patients with peripheral arterial disease, physicians should recognize that first treatment failure (PVI or LEB) affects the success of subsequent revascularizations.

Improved efficiency and safety for EVAR with utilization of a hybrid room

OBJECTIVE

Access to a hybrid endovascular suite is touted as a necessity for advanced endovascular aneurysm repair (EVAR) to improve imaging accuracy and safety. Yet there remain little data documenting this intuitive advantage of a hybrid setup versus a traditional operating room (OR) utilizing a portable fluoroscopic unit (C-arm) for imaging. We hypothesized that standard elective EVAR performed in a hybrid suite would improve procedural efficiency and accuracy, as well minimize patient exposure to both contrast and radiation.

METHODS

We retrospectively reviewed a single attending surgeon's EVAR practice, which encompassed the transition to a hybrid endovascular suite (opened July 2010). Only consecutive abdominal aneurysms were included in the analysis to attempt to create a homogenous cohort. All emergent, aorto-uni-iliac (AUI), snorkel, fenestrated, or hybrid procedures were excluded. Standard variables evaluated and compared between the two study subgroups included fluoroscopy time, operative time, contrast use, stent-graft component utilization, complication rates, and short-term endoleaks.

RESULTS

From January 2008 to August 2012, we performed 213 EVAR procedures for abdominal aortic aneurysms. After excluding emergent, AUI, snorkel, or hybrid procedures, we analyzed 109 routine EVARs. Fifty-eight consecutive cases were done in the OR with a C-arm until July 2010, and the last 51 cases were done in the hybrid room. Both groups were well matched in terms of demographics, aneurysm morphology, and procedural characteristics. No difference was found in terms of complication rates or operative mortality, although there was a trend towards decreased fluoroscopy time, type I/III endoleaks, and a number of additional endograft components utilized. Compared with patients repaired in the OR/C-arm, EVAR done in the hybrid room resulted in less total OR time and contrast usage (p < .05).

CONCLUSIONS

Routine EVAR performed in a hybrid fixed-imaging suite affords greater efficiency and less harmful exposure of contrast and possible radiation to the patient. Accurate imaging quality and deployment is associated with less need for additional endograft components, which should lead to improved cost efficiency. Confirmation of these findings might be necessary in a randomized control trial to fully justify the capital expenditure necessary for hybrid endovascular suites.

Presentation, treatment, and outcome differences between men and women undergoing revascularization or amputation for lower extremity peripheral arterial disease

OBJECTIVE

Prior studies have suggested treatment and outcome disparities between men and women for lower extremity peripheral arterial disease after surgical bypass. Given the recent shift toward endovascular therapy, which has increasingly been used to treat claudication, we sought to analyze sex disparities in presentation, revascularization, amputation, and inpatient mortality.

METHODS

We identified individuals with intermittent claudication and critical limb ischemia (CLI) using International Classification of Diseases, Ninth Revision codes in the Nationwide Inpatient Sample from 1998 to 2009. We compared presentation at time of intervention (intermittent claudication vs CLI), procedure (open surgery vs percutaneous transluminal angioplasty or stenting vs major amputation), and in-hospital mortality for men and women. Regional and ambulatory trends were evaluated by performing a separate analysis of the State Inpatient and Ambulatory Surgery Databases from four geographically diverse states: California, Florida, Maryland, and New Jersey.

RESULTS

From the Nationwide Inpatient Sample, we identified 1,797,885 patients (56% male) with intermittent claudication (26%) and CLI (74%), who underwent 1,865,999 procedures (41% open surgery, 20% percutaneous transluminal angioplasty or stenting, and 24% amputation). Women were older at the time of intervention by 3.5 years on average and more likely to present with CLI (75.9% vs 72.3%; odds ratio [OR], 1.21; 95% confidence interval [CI], 1.21-1.23; P < .01). Women were more likely to undergo endovascular procedures for both intermittent claudication (47% vs 41%; OR, 1.27; 95% CI, 1.25-1.28; P < .01) and CLI (21% vs 19%; OR, 1.14; 95% CI, 1.13-1.15; P < .01). From 1998 to 2009, major amputations declined from 18 to 11 per 100,000 in men and 16 to 7 per 100,000 in women, predating an increase in total CLI revascularization procedures that was seen starting in 2005 for both men and women. In-hospital mortality was higher in women regardless of disease severity or procedure performed even after adjusting for age and baseline comorbidities (.5% vs .2% after percutaneous transluminal angioplasty or stenting for intermittent claudication; 1.0% vs .7% after open surgery for intermittent claudication; 2.3% vs 1.6% after percutaneous transluminal angioplasty or stenting for CLI; 2.7% vs 2.2% after open surgery for CLI; P < .01 for all comparisons).

CONCLUSIONS

There appears to be a preference to perform endovascular over surgical revascularization among women, who are older and have more advanced disease at presentation. Percutaneous transluminal angioplasty or stenting continues to be popular and is increasingly being performed in the outpatient setting. Amputation and in-hospital mortality rates have been declining, and women now have lower amputation but higher mortality rates than men. Recent improvements in outcomes are likely the result of a combination of improved medical management and risk factor reduction.

Cardiac Risk Assessment, Morbidity Prediction, and Outcome in the Vascular Intensive Care Unit

Objectives:

The aim of this study is to examine the predictive value of the Lee revised cardiac risk index (RCRI) for a standard vascular intensive care unit (ICU) population as well as assessing the utility of transthoracic echocardiography and the impact of prior coronary artery disease (CAD) and coronary revascularization on patient outcome.

Design:

This is a retrospective review of prospectively maintained Vascubase and prospectively collected ICU data.

Materials and Methods:

Data from 363 consecutive vascular ICU admissions were collected. Findings were used to calculate the RCRI, which was then correlated with patient outcomes. All patients were on optimal medical therapy (OMT) in the form of cardioselective β-blocker, aspirin, statin, and folic acid.

Results:

There was no relationship found between a reduced ejection fraction and patient outcome. Mortality was significantly increased for patients with left ventricular hypertrophy (LVH) as identified on echo (14.9% vs 6.5%, P = .028). The overall complication rates were significantly elevated for patients with valvular dysfunction. Discrimination for the RCRI on receiver–operating characteristic analysis was poor, with an area under the receiver–operating characteristic curve of .621. Model calibration was reasonable with an Hosmer-Lemeshow Ĉ statistic of 2.726 ( P = .256). Of those with known CAD, 41.22% of the patients receiving best medical treatment developed acute myocardial infarction (AMI) compared to 35.3% of those who previously underwent percutaneous cardiac intervention and 23.5% of those who had undergone coronary artery bypass grafting. There was 3-fold increase in major adverse clinical events in patients with troponin rise and LVH.

Conclusions:

The RCRI’s discriminatory capacity is low, and this raises difficulties in assessing cardiac risk in patients undergoing vascular intervention. The AMI is highest in the OMT group without prior cardiac intervention, which mandates protocols to identify patients requiring cardiac intervention prior to vascular procedures.

Utilization trends of cervical artificial disc replacement during the FDA investigational device exemption clinical trials compared to anterior cervical fusion

While anterior cervical discectomy and fusion (ACDF) is the gold standard surgical treatment for cervical disc disease, concerns regarding adjacent segment degeneration lead to the development of cervical disc arthroplasty (CDA). This study compares the utilization trends of CDA versus ACDF during the period of the Food and Drug Administration Investigational Device Exemption clinical trials from 2004 to 2007. The Healthcare Cost and Utilization Project Nationwide Inpatient Sample database was used to identify CDA and ACDF procedures performed in the USA between 2004 and 2007. The prevalence of CDA and ACDF procedures was estimated and stratified by age, sex, diagnosis, census region, payor class, and hospital characteristics. The average length of hospital stay, total charges, and costs were also estimated. The number of CDA surgeries significantly increased annually from 2004 to 2007 and mostly took place at urban non-teaching hospitals. There were no regional differences between CDA and ACDF utilization. There was no difference between sex or admission type between CDA and ACDF patients. ACDF patients were older and had more diabetes, hypertension, and chronic obstructive pulmonary disease. CDA patients were more likely to be discharged home and had shorter hospital stays but had a higher rate of deep venous thrombosis than ACDF patients. Significantly more CDA patients had private insurance while more ACDF patients had Medicare. The average cost was higher for ACDF than CDA. While ACDF dominated surgical intervention for cervical disc disease during the trial period, CDA utilization increased at a significantly greater rate suggesting rapid early adoption.

Fate of the contralateral limb after lower extremity amputation

OBJECTIVE

Lower extremity amputation is often performed in patients where both lower extremities are at risk due to peripheral arterial disease or diabetes, yet the proportion of patients who progress to amputation of their contralateral limb is not well defined. We sought to determine the rate of subsequent amputation on both the ipsilateral and contralateral lower extremities following initial amputation.

METHODS

We conducted a retrospective review of all patients undergoing lower extremity amputation (exclusive of trauma or tumor) at our institution from 1998 to 2010. We used International Classification of Diseases-Ninth Revision codes to identify patients and procedures as well as comorbidities. Outcomes included the proportion of patients at 1 and 5 years undergoing contralateral and ipsilateral major and minor amputation stratified by initial major vs minor amputation. Cox proportional hazards regression analysis was performed to determine predictors of major contralateral amputation.

RESULTS

We identified 1715 patients. Mean age was 67.2 years, 63% were male, 77% were diabetic, and 34% underwent an initial major amputation. After major amputation, 5.7% and 11.5% have a contralateral major amputation at 1 and 5 years, respectively. After minor amputation, 3.2% and 8.4% have a contralateral major amputation at 1 and 5 years while 10.5% and 14.2% have an ipsilateral major amputation at 1 and 5 years, respectively. Cox proportional hazards regression analysis revealed end-stage renal disease (hazard ratio [HR], 3.9; 95% confidence interval [CI], 2.3-6.5), chronic renal insufficiency (HR, 2.2; 95% CI, 1.5-3.3), atherosclerosis without diabetic neuropathy (HR, 2.9; 95% CI, 1.5-5.7), atherosclerosis with diabetic neuropathy (HR, 9.1; 95% CI, 3.7-22.5), and initial major amputation (HR, 1.8; 95% CI, 1.3-2.6) were independently predictive of subsequent contralateral major amputation.

CONCLUSIONS

Rates of contralateral limb amputation are high and predicted by renal disease, atherosclerosis, and atherosclerosis with diabetic neuropathy. Physicians and patients should be alert to the high risk of subsequent amputation in the contralateral leg. All patients, but particularly those at increased risk, should undergo close surveillance and counseling to help prevent subsequent amputations in their contralateral lower extremity.

Controlled Reperfusion Versus Conventional Treatment of the Acutely Ischemic Limb

Background—

Amputation rates and mortality in patients with severe acute limb ischemia remain high. The protective effect of controlled reperfusion (CR) on tissue damage because of local and systemic reperfusion injury is unclear.

Methods and Results—

A total of 174 patients from 14 centers were randomized between conventional treatment (CT) by thrombembolectomy and normal blood reperfusion and thrombembolectomy followed by CR. The primary end point was amputation-free survival (AFS) after 4 weeks (CT, 82.4%; CR, 82.6%). Secondary end points were AFS (CT, 62.4%; CR, 63.1%) and overall survival (CT, 71.6%; CR, 76.3%) after 1 year. Analysis of the prognostic effects of preoperative factors revealed a strong adverse effect of bilateral involvement on AFS. In the subgroup with unilateral ischemia (n=160), age >80 years and central localization of the occlusion had independent negative prognostic effects on AFS. In the per-protocol population of 104 patients with unilateral ischemia, treatment per protocol, and successful revascularization, amputation or death within 4 weeks occurred in only 8% as compared with 33% in patients not fulfilling these criteria. No differences between treatment groups CT and CR were found, neither overall nor in the per-protocol population nor in patient subgroups defined by other pre- and intraoperative factors.

Conclusions—

Similar AFS in patients with CT or with CR was observed in this large randomized multicenter trial.

Clinical Trial Registration—

URL: http://www.drks.de . Unique identifier: DRKS00000579.

Preoperative inferior mesenteric artery embolization before endovascular aneurysm repair: decreased incidence of type II endoleak and aneurysm sac enlargement with 24-month follow-up

PURPOSE

To review the effect of preoperative embolization of the inferior mesenteric artery (IMA) before endovascular aneurysm repair (EVAR) on subsequent endoleaks and aneurysm growth.

MATERIALS AND METHODS

Between August 2002 and May 2010, 108 patients underwent IMA embolization before EVAR. Coil embolization was performed in all patients in whom the IMA was successfully visualized and accessed during preoperative conventional angiography. In this cohort, the incidences of type II endoleak, aneurysm sac volume enlargement at 24 months, and repeat intervention were compared with a group of 158 consecutive patients with a patent IMA on preoperative computed tomography angiography but not on conventional angiography, who therefore did not undergo preoperative embolization.

RESULTS

The incidence of type II endoleak was significantly higher in patients not treated with embolization (49.4% [78 of 158] vs 34.3% [37 of 108]; P = .015). The incidence of secondary intervention for type II endoleak embolization was also significantly higher in those who did not undergo embolization (7.6% [12 of 158] vs 0.9% [one of 108]; P = .013). At 24 months, an increase in aneurysm sac volume was observed in 47% of patients in the nonembolized cohort (21 of 45), compared with 26% of patients in the embolized cohort (13 of 51; P = .03). No aneurysm ruptures or aneurysm-related deaths were observed in either group. One patient in the embolization group developed mesenteric ischemia and ultimately died.

CONCLUSIONS

Preoperative embolization of the IMA was associated with reduced incidences of type II endoleak, aneurysm sac volume enlargement at 24 months, and secondary intervention.

Perioperative statin therapy for improving outcomes during and after noncardiac vascular surgery

BACKGROUND

Patients undergoing vascular surgery are a high-risk population with widespread atherosclerosis, an adverse cardiovascular risk profile and often multiple co-morbidities. Postoperative cardiovascular complications, including myocardial infarct (MI), are common. Statins are the medical treatment of choice to reduce high cholesterol levels. Evidence is accumulating that patients taking statins at the time of surgery are protected against a range of perioperative complications, but the specific benefits for patients undergoing noncardiac vascular surgery are not clear.

OBJECTIVES

We examined whether short-term statin therapy, commenced before or on the day of noncardiac vascular surgery and continuing for at least 48 hours afterwards, improves patient outcomes including the risk of complications, pain, quality of life and length of hospital stay. We also examined whether the effect of statin therapy on these outcomes changes depending on the dose of statin received.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 7), MEDLINE via Ovid SP (1966 to August 2012), EMBASE via Ovid SP (1966 to August 2012), CINAHL via EBSCO host (1966 to August 2012) and ISI Web of Science (1946 to July 2012) without any language restriction. We used a combination of free text search and controlled vocabulary search. The results were limited to randomized controlled clinical trials (RCTs). We conducted forwards and backwards citation of key articles and searched two clinical trial Websites for ongoing trials (www.clinicaltrials.gov and http://www.controlled-trials.com).

SELECTION CRITERIA

We included RCTs that had compared short-term statin therapy, either commenced de novo or with existing users randomly assigned to different dosages, in adult participants undergoing elective and emergency noncardiac arterial surgery, including both open and endovascular procedures. We defined short-term as commencing before or on the day of surgery and continuing for at least 48 hours afterwards.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data, including information on adverse events. We contacted study authors for additional information. We performed separate analyses for the comparisons of statin with placebo/no treatment and between different doses of statin. We presented results as pooled risk ratios (RRs) with 95% confidence intervals (CIs) based on random-effects models (inverse variance method). We employed the Chi(2) test and calculated the I(2) statistic to investigate study heterogeneity.

MAIN RESULTS

We identified six eligible studies in total. The six Included studies were generally of high quality, but the largest eligible study was excluded because of concerns about its validity. Study populations were statin naive, which led to a considerable loss of eligible participants.Five RCTs compared statin use with placebo or standard care. We pooled results from three studies, with a total of 178 participants, for mortality and non-fatal event outcomes. In the statin group, 7/105 (6.7%) participants died within 30 days of surgery, as did 10/73 (13.7%) participants in the control group. Only one death in each group was from cardiovascular causes, with an incidence of 0.95% in statin participants and 1.4% in control participants, respectively. All deaths occurred in a single study population, and so effect estimates were derived from one study only. The risk ratio (RR) of all-cause mortality in statin users showed a non-significant decrease in risk (RR 0.73, 95% CI 0.31 to 1.75). For cardiovascular death, the risk ratio was 1.05 (95% CI 0.07 to 16.20). Non-fatal MI within 30 days of surgery was reported in three studies and occurred in 4/105 (3.8%) participants in the statin group and 8/73 (11.0%) participants receiving placebo, for a non-significant decrease in risk (RR 0.47, 95% CI 0.15 to 1.52). Several studies reported muscle enzyme levels as safety measures, but only three (with a total of 188 participants) reported explicitly on clinical muscle syndromes, with seven events reported and no significant difference found between statin users and controls (RR 0.94, 95% CI 0.24 to 3.63). The only participant-reported outcome was nausea in one small study,with no significant difference in risk between groups.Two studies compared different doses of atorvastatin, with a total of 145 participants, but reported data were not sufficient to allow us to determine the effect of higher doses on any outcome.

AUTHORS' CONCLUSIONS

Evidence was insufficient to allow review authors to conclude that statin use resulted in either a reduction or an increase in any of the outcomes examined. The existing body of evidence leaves questions about the benefits of perioperative use of statins for vascular surgery unanswered. Widespread use of statins in the target population means that it may now be difficult for researchers to undertake the large RCTs needed to demonstrate any effect on the incidence of postoperative cardiovascular events. However, participant-reported outcomes have been neglected and warrant further study.

Critical limb ischemia: reporting outcomes and quality

The impetus to pursue quality in limb salvage is high in the current economic environment. This has been spurred on by the diffusion of multiple technologies, the lack of well-defined cost-effectiveness benchmarks, and the paucity of process and structure benchmarks. Furthermore, no national database exists to capture current activity and trends, and lead structure and process changes that could analyze outcomes and improve standards in peripheral interventions for limb salvage. This manuscript examines the challenges in measuring outcomes and quality in limb salvage and explores the components necessary for ensuring quality in limb salvage interventions.

Cardiovascular events are not associated with MTHFR polymorphisms, but are associated with methotrexate use and traditional risk factors in US veterans with rheumatoid arthritis

OBJECTIVE

C677T and A1298C polymorphisms in the enzyme methylenetetrahydrofolate reductase (MTHFR) have been associated with increased cardiovascular (CV) events in non-rheumatoid arthritis (RA) populations. We investigated potential associations of MTHFR polymorphisms and use of methotrexate (MTX) with time-to-CV event in data from the Veterans Affairs Rheumatoid Arthritis (VARA) registry.

METHODS

VARA participants were genotyped for MTHFR polymorphisms. Variables included demographic information, baseline comorbidities, RA duration, autoantibody status, and disease activity. Patients' comorbidities and outcome variables were defined using International Classification of Diseases-9 and Current Procedural Terminology codes. The combined CV event outcome included myocardial infarction (MI), percutaneous coronary intervention, coronary artery bypass graft surgery, and stroke. Cox proportional hazards regression was used to model the time-to-CV event.

RESULTS

Data were available for 1047 subjects. Post-enrollment CV events occurred in 97 patients (9.26%). Although there was a trend toward reduced risk of CV events, MTHFR polymorphisms were not significantly associated with time-to-CV event. Time-to-CV event was associated with prior stroke (HR 2.01, 95% CI 1.03-3.90), prior MI (HR 1.70, 95% CI 1.06-2.71), hyperlipidemia (HR 1.57, 95% CI 1.01-2.43), and increased modified Charlson-Deyo index (HR 1.23, 95% CI 1.13-1.34). MTX use (HR 0.66, 95% CI 0.44-0.99) and increasing education (HR 0.87, 95% CI 0.80-0.95) were associated with a lower risk for CV events.

CONCLUSION

Although MTHFR polymorphisms were previously associated with CV events in non-RA populations, we found only a trend toward decreased association with CV events in RA. Traditional risk factors conferred substantial CV risk, while MTX use and increasing years of education were protective.

Endovascular Versus Open Repair of Popliteal Artery Aneurysms

Objective:

The management of popliteal artery aneurysms (PAAs) has undergone significant transition from open surgery to endovascular graft placement with few longitudinal data evaluating outcomes.

Methods:

The Centers of Medicare & Medicaid Services Inpatient claims (2005-2007) were queried with a diagnosis of lower extremity artery aneurysm in association with elective Current Procedural Terminology codes for open (OPEN group) and endovascular (ENDO group) repair.

Results:

A total of 2962 patients were identified. Endovascular interventions significantly increased over the time of the study (11.7% vs 23.6%, P < .0001). Overall complication rates for OPEN and ENDO groups did not differ significantly (11.3% vs 9.3%; P = .017). No differences in the 30- and 90-day mortality rates were found between OPEN versus ENDO groups. The ENDO group had greater 30- and 90-day reinterventions (4.6% vs 2.1%, P = .001 and 11.8% vs 7.4%, P = .0007, respectively). Length of stay (4.5 days vs 2.5 days, P < .0001) and charges ($43 180 vs $35 540, P < .0001) were greater for OPEN group.

Conclusion:

Despite a significant increase in the utilization of endovascular repair of PAAs, endovascular repair was associated with greater reinterventions over time and did not offer a mortality or cost benefit.

Haemodynamic optimisation in lower limb arterial surgery: room for improvement?

BACKGROUND

Goal-directed therapy has been proposed to improve outcome in high-risk surgery patients. The aim of this study was to investigate whether individualised goal-directed therapy targeting stroke volume and oxygen delivery could reduce the number of patients with post-operative complications and shorten hospital length of stay after open elective lower limb arterial surgery.

METHODS

Forty patients scheduled for open elective lower limb arterial surgery were prospectively randomised. The LiDCO™plus system was used for haemodynamic monitoring. In the intervention group, stroke volume index was optimised by administering 250 ml aliquots of colloid intraoperatively and during the first 6 h post-operatively. Following surgery, fluid optimisation was supplemented with dobutamine, if necessary, targeting an oxygen delivery index level ≥ 600 ml/min(/) m(2) in the intervention group. Central haemodynamic data were blinded in control patients. Patients were followed up after 30 days.

RESULTS

In the intervention group, stroke volume index, and cardiac index were higher throughout the treatment period (45 ± 10 vs. 41 ± 10 ml/m(2), P < 0.001, and 3.19 ± 0.73 vs. 2.77 ± 0.76 l/min(/) m(2), P < 0.001, respectively) as well as post-operative oxygen delivery index (527 ± 120 vs. 431 ± 130 ml/min(/) m(2), P < 0.001). In the same group, 5/20 patients had one or more complications vs. 11/20 in the control group (P = 0.05). After adjusting for pre-operative and intraoperative differences, the odds ratio for ≥ 1 complications was 0.18 (0.04-0.85) in the intervention group (P = 0.03). The median length of hospital stay did not differ between groups.

CONCLUSION

Perioperative individualised goal-directed therapy may reduce post-operative complications in open elective lower limb arterial surgery.

Predictors and outcomes of restenosis following tibial artery endovascular interventions for critical limb ischemia

OBJECTIVE

Restenosis following tibial artery endovascular interventions (TAEIs) is thought to be benign but is not well characterized. This study examines the consequences and predictors of recurrent stenosis of TAEIs for critical limb ischemia.

METHODS

All TAEIs for critical limb ischemia performed between 2004 and 2010 were retrospectively reviewed. Restenosis was detected by noninvasive imaging and angiography when indicated. Restenoses were identified and the limb outcomes recorded. Tibial reinterventions were performed only for persistent, worsening, or recurrent tissue loss or rest pain with evidence of recurrence on duplex ultrasound or hemodynamic imaging. The χ test and logistic regression were applied as indicated. One-year patency rates were calculated using the Kaplan-Meier method.

RESULTS

A total of 235 limbs in 210 patients were treated for critical limb ischemia (70% tissue loss, 30% rest pain). Tissue loss included gangrene (49%) and ulcers (51%), and involved the forefoot (80%), the heel (14%), or both (6%). Seventy-eight percent of limbs had Trans-Atlantic InterSociety Consensus C/D lesions, with mean preoperative runoff score of 12. Interventions were isolated tibial (45%) or multilevel (55%) (including tibial). Mean postoperative runoff score improved to 6.6, but restenosis occurred in 96 limbs (41%) at a mean of 4 months. The 1-year primary patency was 59% with a mean follow-up of 9 months. Restenosis presented with a persistent wound (32%), worsened wound (42%), rest pain (16%), or no symptoms (10%). A repeat TAEI was performed in 42 (44%), major amputation in 26 (27%), open bypass in 20 (21%), and observation in eight (8%). The overall amputation rate was 13%, but limb loss was significantly higher in patients with restenosis (n = 26 [27%]) than in patients with no restenosis (n = 5 [4%]; P < .001). Patients with restenosis and tissue loss were more likely to have presented with gangrene (63% vs 38%; P = .0003) but had comparable wound distribution (P = NS). There was a trend toward a higher restenosis rate in patients with renal insufficiency (odds ratio, 5.57; P = .08), but this was unaffected by diabetes, statin therapy, or smoking (P = NS). The rate of repeat intervention after the first reintervention was 36%, with an 87% overall limb salvage rate.

CONCLUSIONS

TAEIs can be used successfully to treat patients with critical limb ischemia with acceptable limb salvage rates. Special attention should be given to patients with extensive tissue loss or gangrene because they are at risk for early restenosis and subsequent limb loss. Strict wound and hemodynamic surveillance, wound care, and timely reinterventions are crucial to achieve successful outcomes in this patient population. Amputation or alternative revascularization options, when feasible, should be considered in patients with restenosis and tissue loss given the high rate of limb loss with tibial reinterventions.

Lower-limb amputee rehabilitation in Australia: analysis of a national data set 2004 - 10

Objective. Examine demographics, clinical characteristics and rehabilitation outcomes of lower-limb amputees, using the Australasian Rehabilitation Outcomes Centre (AROC) database. Methods. Lower-limb amputee rehabilitation separations between 2004 and 2010 were identified using AROC impairment codes 5.3–5.7.1 Analysis was conducted by year, impairment code, Australian National Sub-acute and Non-Acute Patient (AN-SNAP) classification (S2–224, Functional Independence Measure (FIM) motor(Mot) score 72–91; S2–225, FIM (Mot) score 14–71) and states of Australia. Results. Mean length of stay (LOS) for all lower-limb amputee episodes was 36.1 days (95% confidence interval (CI): 35.4–36.9). Majority of episodes were unilateral below knee (63.6%), males (71.8%) with a mean age of 67.9 years (95% CI: 67.6–68.3). Year-on-year analysis revealed a trend for increasing LOS and decreasing age. Analysis by impairment code demonstrated no significant difference in rehabilitation outcomes. Analysis by AN-SNAP found that LOS was 16.2 days longer for S2–225 than for S2–224 (95% CI: 14.7–17.8, P < 0.001), and FIM (Mot) change was 12.0 points higher for S2–225 than for S2–224 (95% CI: 11.5–12.6, P < 0.001). Analysis by states revealed significant variation in LOS, FIM (Mot) change and FIM (Mot) efficiency which may be associated with variations in organisation of rehabilitation services across states. Conclusion. Although amputees represented a comparatively small proportion of all rehabilitation episodes in Australia, their LOS was significant. Unlike many other rehabilitation conditions, there was no evidence of decreasing LOS over time. AN-SNAP classes were effective in distinguishing rehabilitation outcomes, and could potentially be used more effectively in planning rehabilitation programs. What is known about the topic? Literature reporting on the rehabilitation outcomes of cohorts of lower-limb amputees in Australia is limited to individual sites. No previous literature was identified that reported national data. What does this paper add? This study investigates amputee rehabilitation at a national level over a 7-year observation period (2004–10) and comprises 6588 episodes. It reports the national demographics, clinical characteristics and rehabilitation outcomes, with the aim of identifying findings that have implications for practitioners. What are the implications for practitioners? Although only a small proportion of all episodes in the AROC database, this subset of lower-limb amputee episodes has provided a useful snapshot of the current state of amputee rehabilitation in Australia. We believe these findings have significant implications for practitioners in delivery of amputee rehabilitation services across Australia. Practitioners may benefit from adjusting service delivery based upon the decreasing age of lower limb amputees. Findings from this study also indicate that AN-SNAP classifications are effective in discriminating amputee rehabilitation outcomes and may be used to streamline rehabilitation services and provide a more efficient and effective rehabilitation service to prevent further increases in LOS.

Using risk models to improve patient selection for high-risk vascular surgery

Vascular surgeons frequently perform procedures aimed at limiting death, stroke, or amputation on patients who present with diseases such as aortic aneurysms, carotid atherosclerosis, and peripheral arterial occlusive disease. However, now more than ever surgeons must balance the potential benefits associated with these interventions with the risks of physiologic insult for these elderly patients, who often have significant comorbidity burdens and the potential for costly complications. In this paper, we highlight how regional and national datasets can help surgeons identify which patients are most likely to benefit from vascular operations and which patients are most likely to suffer complications in the postoperative period. By using these guidelines to improve patient selection, our risk models can help patients, physicians, and policymakers improve the clinical effectiveness of surgical and endovascular treatments for vascular disease.

The effects of normalizing hyperhomocysteinemia on clinical and operative outcomes in patients with critical limb ischemia

PURPOSE

To assess the outcome of patients with medically treated hyperhomocysteinemia (HHC) requiring intervention for critical limb ischemia (CLI).

METHODS

A parallel observational study was conducted to compare the clinical and revascularization outcomes of CLI patients who received standardized treatment for HHC preoperatively (folic acid and vitamin B12) vs. contemporaneous patients with normal homocysteine levels. The threshold for HHC diagnosis was 13.0 μmol/L. From 2009 to 2011, 169 patients underwent revascularization procedures for CLI. Of these, all 66 patients (40 men; mean age 69.6 ± 11.2 years) with HHC (mean 17.3 μmol/L, range 13.5-34.9) were treated to normalize the homocysteine level prior to lower limb revascularization. The remaining 103 patients (58 men; mean age 72.7±8.1 years) had normal homocysteine levels (8.2 μmol/L, range 5-12.3) before revascularization. The primary endpoint was symptomatic and hemodynamic improvement in the treated HHC group. The secondary endpoints were all-cause survival, binary restenosis, reintervention, amputation-free survival, and major adverse events. The treated HHC cohort was compared to an age/sex-matched historical group of patients with untreated HHC from 2002 to 2006 before HHC pretreatment became routine. All interventions (endovascular, hybrid, and open) were performed by the same surgeon, and the groups were evenly matched.

RESULTS

Patients with HHC were treated for a mean 12.2 days, which significantly reduced their mean homocysteine level after 3 weeks to 10.1 μmol/L (range 6.2-14.4, p<0.05). After revascularization, immediate clinical improvement was similar between normal homocysteine and medically corrected HHC groups. There was no significant difference in time to binary restenosis (p=0.822). Secondary endpoints and all-cause mortality were similar. Multivariate logistic regression showed that untreated HHC was a significant factor for graft occlusion and limb loss (p<0.0001), but medically corrected HHC was no longer predictive of adverse operative outcome.

CONCLUSION

Patients with medically corrected HHC have similar outcomes compared to those with normal homocysteine levels. Thus, aggressively treating HHC with folic acid and vitamin B12 may help enhance the clinical outcome of CLI patients undergoing revascularization.

Changes in abdominal aortic aneurysm rupture and short-term mortality, 1995-2008: a retrospective observational study

OBJECTIVE

To examine the modern epidemiology of abdominal aortic aneurysm (AAA) rupture and short-term AAA-related mortality after the introduction of endovascular aneurysm repair (EVAR).

BACKGROUND

Previous epidemiologic studies have demonstrated stable rates of AAA repair, repair mortality, and AAA rupture. Recently, EVAR has been introduced as a less invasive treatment method, and its use has expanded to more than 75% of elective AAA repairs.

METHODS

We identified Medicare beneficiaries undergoing AAA repair and those hospitalized with a ruptured AAA during the period 1995 to 2008 and calculated standardized annual rates of AAA-related deaths due to either elective repair or rupture.

RESULTS

A total of 338,278 patients underwent intact AAA repair during the study period. There were 69,653 patients with AAA rupture, of whom 47,524 underwent repair. Intact repair rates increased substantially in those older than 80 years (57.7-92.3 per 100,000, P < 0.001) but decreased in those 65 to 74 years old (81.8-68.9, P < 0.001). A decline in ruptures with and without repair was seen in all age groups. By 2008, 77% of all intact repairs and 31% of all rupture repairs were performed with EVAR (P < 0.001). Operative mortality declined during the study period for both intact (4.9%-2.4%, P < 0.001) and ruptured (44.1%-36.3%, P < 0.001) AAA repair. Short-term AAA-related deaths decreased by more than half (26.1-12.1 per 100,000, P < 0.001), with the greatest decline occurring in those older than 80 years (53.7-27.3, P < 0.001).

CONCLUSIONS

A recent decline in AAA rupture and short-term AAA-related mortality is demonstrated and likely related in part to the introduction and expansion of EVAR. This is due to decreased deaths from ruptures (with and without repair) and decreased mortality with intact repairs, particularly in patients older than 80 years.

Causes and implications of readmission after abdominal aortic aneurysm repair

OBJECTIVE

To determine the frequency, causes, predictors, and consequences of 30-day readmission after abdominal aortic aneurysm (AAA) repair.

BACKGROUND DATA

Centers for Medicare & Medicaid Services (CMS) will soon reduce total Medicare reimbursements for hospitals with higher-than-predicted 30-day readmission rates after vascular surgical procedures, including AAA repair. However, causes and factors leading to readmission in this population have never before been systematically analyzed.

METHODS

We analyzed elective AAA repairs over a 2-year period from the CMS Chronic Conditions Warehouse, a 5% national sample of Medicare beneficiaries.

RESULTS

A total of 2481 patients underwent AAA repair--1502 endovascular aneurysm repair (EVAR) and 979 open aneurysm repair. Thirty-day readmission rates were equivalent for EVAR (13.3%) and open repair (12.8%). Although wound complication was the most common reason for readmission after both procedures, the relative frequency of other causes differed-eg, bowel obstruction was common after open repair, and graft complication after EVAR. In multivariate analyses, preoperative comorbidities had a modest effect on readmission; however, postoperative factors, including serious complications leading to prolonged length of stay and discharge destination other than home, had a profound influence on the probability of readmission. The 1-year mortality in readmitted patients was 23.4% versus 4.5% in those not readmitted (P < 0.001).

CONCLUSIONS

Early readmission is common after AAA repair. Adjusting for comorbidities, postoperative events predict readmission, suggesting that proactively preventing, detecting, and managing postoperative complications may provide an approach to decreasing readmissions, with the potential to reduce cost and possibly enhance long-term survival.

Anesthesia-based evaluation of outcomes of lower-extremity vascular bypass procedures

BACKGROUND

This report examines the effects of regional versus general anesthesia for infrainguinal bypass procedures performed in the treatment of critical limb ischemia (CLI).

METHODS

Nonemergent infrainguinal bypass procedures for CLI (defined as rest pain or tissue loss) were identified using the 2005 to 2008 American College of Surgeons National Surgical Quality Improvement Program database using International Classification of Disease, ninth edition, and Current Procedure Terminology codes. Patients were classified according to National Surgical Quality Improvement Program data as receiving either general anesthesia or regional anesthesia. The regional anesthesia group included those specified as having regional, spinal, or epidural anesthesia. Demographic, medical, risk factor, operative, and outcomes data were abstracted for the study sample. Individual outcomes were evaluated according to the following morbidity categories: wound, pulmonary, venous thromboembolic, genitourinary, cardiovascular, and operative. Length of stay, total morbidity, and mortality were also evaluated. Associations between anesthesia types and outcomes were evaluated using linear or logistic regression.

RESULTS

A total of 5,462 inpatient hospital visits involving infrainguinal bypasses for CLI were identified. Mean patient age was 69 ± 12 years; 69% were Caucasian; and 39% were female. In all, 4,768 procedures were performed using general anesthesia and 694 with regional anesthesia. Patients receiving general anesthesia were younger and significantly more likely to have a history of smoking, previous lower-extremity bypass, previous amputation, previous stroke, and a history of a bleeding diathesis including the use of warfarin. Patients receiving regional anesthesia had a higher prevalence of chronic obstructive pulmonary disease. Tibial-level bypasses were performed in 51% of procedures, whereas 49% of procedures were popliteal-level bypasses. Cases performed using general anesthesia demonstrated a higher rate of resident involvement, need for blood transfusion, and operative time. There was no difference in the rate of popliteal-level and infrapopliteal-level bypasses between groups. Infrapopliteal bypass procedures performed using general anesthesia were more likely to involve prosthetic grafts and composite vein. Mortality occurred in 157 patients (3%). The overall morbidity rate was 37%. Mean and median lengths of stay were 7.5 days (± 8.1) and 6.0 days (Q1: 4.0, Q3: 8.0), respectively. Multivariate analyses demonstrated no significant differences by anesthesia type in the incidence of morbidity, mortality, or length of stay.

CONCLUSION

These results provide no evidence to support the systematic avoidance of general anesthesia for lower-extremity bypass procedures. These data suggest that anesthetic choice should be governed by local expertise and practice patterns.

Preoperative prediction of mortality within 1 year after elective thoracic endovascular aortic aneurysm repair

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) is known to have a survival benefit over open repair in patients with descending thoracic aneurysms and has become a mainstay of therapy. Because death before 1 year after TEVAR likely indicates an ineffective therapy, we have created a predictive model for death within 1 year using factors available in the preoperative setting.

METHODS

A registry of 526 TEVARs performed at the University of Florida between September 2000 and November 2010 was queried for patients with degenerative descending thoracic aneurysm as their primary pathology. Procedures with emergent or urgent indications were excluded. Preoperatively available variables, such as baseline comorbidities, anatomic-, and procedure-specific planning details, were recorded. Univariate predictors of death were analyzed with multivariable Cox proportional hazards to identify independent predictors of 30-day (death within 30 days) and 1-year mortality (death within 1 year) after TEVAR.

RESULTS

A total of 224 patients were identified and evaluated. The 30-day mortality rate was 3% (n = 7) and the 1-year mortality rate was 15% (n = 33). Multivariable predictors of 1-year mortality (hazard ratios [95% confidence interval]) included: age >70 years (5.8 [2.1-16.0]; P = .001), adjunctive intraoperative procedures (eg, brachiocephalic or visceral stents, or both, concomitant arch debranching procedures; 4.5 [1.9-10.8]; P = .001), peripheral arterial disease (3.0 [1.4-6.7]; P = .006), coronary artery disease (2.4 [1.1-4.9]; P = .02), and chronic obstructive pulmonary disease (1.9 [1.0-3.9]; P = .06). A diagnosis of hyperlipidemia was protective (0.4 [0.2-0.7]; P = .006). When patients were grouped into those with one, two, three, or four or more of these risk factors, the predicted 1-year mortality was 1%, 3%, 10%, 27%, and 54%, respectively.

CONCLUSIONS

Factors are available in the preoperative setting that are predictive of death within 1 year after TEVAR and can guide clinical decision making regarding the timing of repair. Patients with multiple risk factors, such as age ≥ 70 years, coronary artery disease, chronic obstructive pulmonary disease, and a need for an extensive procedure involving adjunctive therapies, have a high predicted mortality within 1 year and may be best served by waiting for a larger aneurysm size to justify the risk of intervention.

Temporal network based analysis of cell specific vein graft transcriptome defines key pathways and hub genes in implantation injury

Vein graft failure occurs between 1 and 6 months after implantation due to obstructive intimal hyperplasia, related in part to implantation injury. The cell-specific and temporal response of the transcriptome to vein graft implantation injury was determined by transcriptional profiling of laser capture microdissected endothelial cells (EC) and medial smooth muscle cells (SMC) from canine vein grafts, 2 hours (H) to 30 days (D) following surgery. Our results demonstrate a robust genomic response beginning at 2 H, peaking at 12-24 H, declining by 7 D, and resolving by 30 D. Gene ontology and pathway analyses of differentially expressed genes indicated that implantation injury affects inflammatory and immune responses, apoptosis, mitosis, and extracellular matrix reorganization in both cell types. Through backpropagation an integrated network was built, starting with genes differentially expressed at 30 D, followed by adding upstream interactive genes from each prior time-point. This identified significant enrichment of IL-6, IL-8, NF-κB, dendritic cell maturation, glucocorticoid receptor, and Triggering Receptor Expressed on Myeloid Cells (TREM-1) signaling, as well as PPARα activation pathways in graft EC and SMC. Interactive network-based analyses identified IL-6, IL-8, IL-1α, and Insulin Receptor (INSR) as focus hub genes within these pathways. Real-time PCR was used for the validation of two of these genes: IL-6 and IL-8, in addition to Collagen 11A1 (COL11A1), a cornerstone of the backpropagation. In conclusion, these results establish causality relationships clarifying the pathogenesis of vein graft implantation injury, and identifying novel targets for its prevention.

Outcomes and practice patterns in patients undergoing lower extremity bypass

BACKGROUND

The appropriate application of endovascular intervention vs bypass for both critical limb ischemia (CLI) and intermittent claudication (IC) remains controversial, and outcomes from large, contemporary series are critical to help inform treatment decisions. Therefore, we sought to define the early and 1-year outcomes of lower extremity bypass (LEB) in a large, multicenter regional cohort, and analyze trends in the use of LEB with or without prior endovascular interventions.

METHODS

The Vascular Study Group of New England database was used to identify all infrainguinal LEB procedures performed between 2003 and 2009. The primary study endpoint was 1-year amputation-free survival (AFS). Secondary endpoints included in-hospital mortality and morbidity, including major adverse cardiac events. Trend analyses were conducted to identify annual trends in the proportion of LEBs performed for an indication of IC, in-hospital outcomes, including mortality and morbidity, and 1-year outcomes, including AFS. Analyses were performed on the entire cohort and then stratified by indication.

RESULTS

Between 2003 and 2009, 2907 patients were identified who underwent LEBs (72% for CLI; 28% for IC). The proportion that underwent LEB for IC increased significantly over the study period (from 19% to 31%; P < .0001). There was a significant increase over time in the proportion of LEBs performed after a previous endovascular intervention among both CLIs (from 11% to 24%; P < .0001) and ICs (from 13% to 23%; P = .02). Neither in-hospital mortality nor cardiac event rates changed significantly among either group. There was no significant change in 1-year AFS in patients with IC (97% in 2003 and 98% in 2008; P for trend .63) or in patients with CLI (73% in 2003 and 81% in 2008; P = .10).

CONCLUSIONS

Over the last 7 years, significant changes in patient selection for LEBs have occurred in New England. The proportion of LEBs performed for ICs as opposed to CLIs has increased. Patients are much more likely to have undergone prior endovascular interventions before undergoing a bypass. In-hospital and 1-year outcomes after LEB for both IC and CLI have remained excellent with no significant changes in AFS.

Carotid endarterectomy and carotid artery stenting utilization trends over time

BACKGROUND

Carotid endarterectomy (CEA) has been the standard in atherosclerotic stroke prevention for over 2 decades. More recently, carotid artery stenting (CAS) has emerged as a less invasive alternative for revascularization. The purpose of this study was to investigate whether an increase in stenting parallels a decrease in endarterectomy, if there are specific patient factors that influence one intervention over the other, and how these factors may have changed over time.

METHODS

Using a nationally representative sample of US hospital discharge records, data on CEA and CAS procedures performed from 1998 to 2008 were obtained. In total, 253,651 cases of CEA and CAS were investigated for trends in utilization over time. The specific data elements of age, gender, payer source, and race were analyzed for change over the study period, and their association with type of intervention was examined by multiple logistic regression analysis.

RESULTS

Rates of intervention decreased from 1998 to 2008 (P < 0.0001). Throughout the study period, endarterectomy was the much more widely employed procedure. Its use displayed a significant downward trend (P < 0.0001), with the lowest rates of intervention occurring in 2007. In contrast, carotid artery stenting displayed a significant increase in use over the study period (P < 0.0001), with the highest intervention rates occurring in 2006. Among the specific patient factors analyzed that may have altered utilization of CEA and CAS over time, the proportion of white patients who received intervention decreased significantly (P < 0.0001). In multivariate modeling, increased age, male gender, white race, and earlier in the study period were significant positive predictors of CEA use.

CONCLUSIONS

Rates of carotid revascularization have decreased over time, although this has been the result of a reduction in CEA despite an overall increase in CAS. Among the specific patient factors analyzed, age, gender, race, and time were significantly associated with the utilization of these two interventions.