Lower Extremity Bypass Surgery Research Articles

Anthrax Toxin Receptor 1 Is Essential for Arteriogenesis in a Mouse Model of Hindlimb Ischemia.

Anthrax toxin receptor 1/tumor endothelial marker 8 (Antxr1 or TEM8) is up-regulated in tumor vasculature and serves as a receptor for anthrax toxin, but its physiologic function is unclear. The objective of this study was to evaluate the role of Antxr1 in arteriogenesis. The role of Antxr1 in arteriogenesis was tested by measuring gene expression and immunohistochemistry in a mouse model of hindlimb ischemia using wild-type and ANTXR1-/- mice. Additional tests were performed by measuring gene expression in in vitro models of fluid shear stress and hypoxia, as well as in human muscle tissues obtained from patients having peripheral artery disease. We observed that Antxr1 expression transiently increased in ischemic tissues following femoral artery ligation and that its expression was necessary for arteriogenesis. In the absence of Antxr1, the mean arterial lumen area in ischemic tissues decreased. Antxr1 mRNA and protein expression was positively regulated by fluid shear stress, but not by hypoxia. Furthermore, Antxr1 expression was elevated in human peripheral artery disease requiring lower extremity bypass surgery. These findings demonstrate an essential physiologic role for Antxr1 in arteriogenesis and peripheral artery disease, with important implications for managing ischemia and other arteriogenesis-dependent vascular diseases.

Circulation : Clinical Summaries

<i>Circulation</i> : Clinical Summaries

The Contemporary Safety and Effectiveness of Lower Extremity Bypass Surgery and Peripheral Endovascular Interventions in the Treatment of Symptomatic Peripheral Arterial Disease

Treatment for symptomatic peripheral artery disease includes lower extremity bypass surgery (LEB) and peripheral endovascular interventions (PVIs); however, limited comparative effectiveness data exist between the 2 therapies. We assessed the safety and effectiveness of LEB and PVI in patients with symptomatic claudication and critical limb ischemia. In a community-based clinical registry at 2 large integrated healthcare delivery systems, we compared 883 patients undergoing PVI and 975 patients undergoing LEB between January 1, 2005 and December 31, 2011. Rates of target lesion revascularization were greater for PVI than for LEB in patients presenting with claudication (12.3±2.7% and 19.0±3.5% at 1 and 3 years versus 5.2±2.4% and 8.3±3.1%, log-rank P<0.001) and critical limb ischemia (19.1±4.8% and 31.6±6.3% at 1 and 3 years versus 10.8±2.5% and 16.0±3.2%, log-rank P<0.001). However, in comparison with PVI, LEB was associated with increased rates of complications up to 30 days following the procedure (37.1% versus 11.9%, P<0.001). There were no differences in amputation rates between the 2 groups. Findings remained consistent in sensitivity analyses by using propensity methods to account for treatment selection. In patients with symptomatic peripheral artery disease, in comparison with LEB, PVI was associated with fewer 30-day procedural complications, higher revascularization rates at 1 and 3 years, and no difference in subsequent amputations.

Unplanned return to operating room after lower extremity arterial bypass is an independent predictor for hospital readmission

Hospital readmissions after surgical operations are considered serious complications and have an impact on health care-associated costs. The Centers for Medicare and Medicaid Services strongly encourage identification and ramification of factors associated with hospital readmissions after operations. Despite advances in endovascular surgery, lower extremity arterial bypass remains the "gold standard" treatment for severe, symptomatic peripheral arterial disease. The purpose of this study was to retrospectively review the factors associated with hospital readmission after lower extremity bypass surgery. The 2013 lower extremity revascularization-targeted American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database and generalized 2013 general and vascular surgery NSQIP Participant Use Data File were used for this study. Patient, diagnosis, and procedure characteristics of patients undergoing lower extremity bypass surgery were assessed. Multivariate logistic regression analysis was used to determine independent risk factors for hospital readmission within 30 days after surgery. A total of 2646 patients (65% male, 35% female) were identified in the NSQIP database who underwent lower extremity open revascularization during the year 2013. Indications for operations included tissue loss (39%), rest pain (32%), and severe claudication (25%). Preoperative ankle-brachial indices were 0.4 to 0.9 (32%) and <0.4 (16.5%). A total of 425 patients (16%) were readmitted within 30 days of index operation. Risk factors associated with readmission included wound complication (odds ratio [OR], 8.54; 95% confidence interval [CI], 6.68-10.92; P < .001), need for reoperation (OR, 5.95; 95% CI, 4.45-7.97; P < .001), postoperative myocardial infarction (OR, 2.19; 95% CI, 1.25-3.83; P = .006), wound dehiscence (OR, 8.45; 95% CI, 4.54-15.71; P < .001), organ or space surgical site infection (OR, 7.62; 95% CI, 2.89-20.14; P < .001), postoperative pneumonia (OR, 2.66; 95% CI, 1.28-5.52; P = .009), progressive renal insufficiency (OR, 4.12; 95% CI, 1.52-11.11; P = .005), superficial surgical site infection (OR, 7.37; 95% CI, 5.31-10.23; P < .001), urinary tract infection (OR, 2.67; 95% CI, 1.42-5.01; P = .002), and deep wound infection (OR, 14.0; 95% CI, 7.62-24.80; P < .001). Readmission after lower extremity bypass surgery is a serious complication. Various factors put a patient at high risk for readmission. Return to the operating room, wound infection, amputation, deep venous thrombosis, and major reintervention on bypass are independent risk factors for hospital readmission. Return to the operating room is associated with a 5.95-fold increase in hospital readmission.

Comparison of risk factors for length of stay and readmission following lower extremity bypass surgery

Recent initiatives to improve health care quality have focused attention on length of stay (LOS) and readmission rates for surgical patients, yet these two outcomes may be inversely related. This study was designed to elucidate the risk factors for both outcomes and to clarify the relationship between them in patients undergoing lower extremity bypass (LEB). Peripheral arterial disease (PAD) patients who underwent LEB were identified from the 2007-2010 California State Inpatient Database. LOS and risk factors were analyzed using Poisson regression. Risk factors for 30-day readmission were analyzed using logistic regression. There were 6307 patients who underwent LEB, and 1291 (20%) were readmitted. The average index LOS was 8.3days for those who were readmitted and 5.5days for those who were not (P< .0001) and was an independent risk factor for 30-day readmission. The significant factors with the largest effect estimates for increased LOS reflected disease severity and postoperative complications: emergency department admission; advanced PAD; postoperative pneumonia, respiratory failure, urinary tract infection, wound/graft infection, graft complication, and discharge to a nursing facility. Independent predictors of readmission, other than LOS, reflected underlying patient factors: advanced PAD, chronic lung disease, diabetes, renal failure, postoperative congestive heart failure, and discharge status. Age, Medicaid or private insurance, and low income were protective. Of the 1291 readmissions, 453 (35%) were for definitive complications. In patients undergoing LEB, LOS is primarily associated with the occurrence of postoperative complications, whereas 30-day readmission is largely explained by underlying patient illness. Additionally, increased LOS is an independent risk factor for readmission. These findings suggest that efforts to reduce both LOS and readmission will be complementary. Furthermore, they support the notion that both LOS and 30-day readmission rates should be risk-adjusted.

Return to Operating Room After Lower Extremity Arterial Bypass Is an Independent Predictor for Hospital Readmission

Hospital readmissions after surgical operations are considered as serious complications and affect health care associated costs. The Centers for Medicare and Medicaid services (CMS) strongly encourages identification and ramification of factors associated with hospital readmissions after operations. Despite advances in endovascular surgery, lower extremity arterial bypass remains the gold standard treatment for severe, symptomatic peripheral arterial disease (PAD). The purpose of this study was to retrospectively review the factors associated with hospital readmission after lower extremity bypass surgery. The 2013 lower extremity revascularization-targeted American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database and generalized 2013 general and vascular surgery ACS-NSQIP Participant Use File were used for this study. Patient, diagnosis, and procedure characteristics of patients undergoing lower extremity bypass surgery were assessed. Multivariate logistic regression analysis was used to determine independent risk factors for hospital readmission ≤30 days after surgery. A total of 2646 patients (males, 35%; females, 65%) underwent lower extremity revascularization during 2013. Indications for operations included tissue loss (39%), rest pain (32%), and severe claudication (25%). Preoperative ankle-brachial indices were 0.4 to 0.9 in 32% and <.4 in 16.5%. A total of 425 patients (16%) were readmitted ≤30 days of the index operation. Risk factors associated with readmission included return to operation room (odds ratio [OR], 9.2), wound infection (OR, 8.5), limb amputation (OR, 5.4), postoperative deep vein thrombosis (OR, 3.8), and major reintervention on bypass (OR, 3.4; P < .05; Fig). Readmission after lower extremity bypass surgery is a serious complication. Various factors put a patient at a high risk for readmission. Return to the operating room, wound infection, amputation, deep vein thrombosis, and major reintervention on bypass are independent risk factors for hospital readmission. Return to the operating room is associated with a ninefold increase in hospital readmission.

PC138. Revised Cardiac Risk Index: An Effective Prognostic Tool for Vascular Postoperative Outcomes

The Revised Cardiac Risk Index (RCRI) is a tool clinicians use for preoperative risk stratification and predicting the likelihood of cardiac complications. This study looked at the role of the RCRI for postoperative outcomes in vascular patients undergoing lower extremity bypass surgery. National Surgical Quality Improvement Program data from 2005 to 2011 of patients undergoing lower extremity revascularization based on Current Procedural Terminology codes were analyzed looking at demographics, revised cardiac risk index variables (coronary heart disease, congestive heart failure, creatinine >2, insulin-dependent diabetes, high-risk surgery, cerebrovascular disease), and outcomes including operative time, days until graft failure, hospital length of stay (LOS), return to operating room, and death. Data were analyzed using single and multivariable linear and logistical regression. A total of 70,440 patients were included, with 25,176 female and 45,264 male patients. Of the 70,400 patients 40,893 (58%) were aged >65 years, with 27,576 (39%) aged between 46 and 65 years. Linear regression showed that with each point increase of the RCRI, operative time increases 5.4 minutes (P < .0001), LOS increases 3.23 days (P < .0001), and graft patency decreases by 0.5 days (P < .05). Through logistic regression, with each point increase in the RCRI the risk of returning to operating room increases 1.4 times (odds ratio, 1.449; 95% confidence interval, 1.412-1.486) and the risk of death increases 1.97 times (odds ratio, 1.972; 95% confidence interval, 1.867-2.083). Using a large retrospective national database, preoperative RCRI can be a useful measure for predicting postoperative outcomes in patients undergoing lower extremity bypass surgery.

Use of completion imaging during infrainguinal bypass in the Vascular Quality Initiative

The purpose of this study was to examine the practice patterns of intraoperative completion imaging (CI) for lower extremity bypass (LEB) in the Vascular Quality Initiative (VQI). A retrospective review of all LEB procedures in the VQI database from January 2003 to October 2013 was performed. Regions with fewer than 200 LEB procedures were excluded from the regional analysis. The modality of CI was defined as duplex ultrasound, angiography, or both. A total of 14,140 LEBs were captured, with the rate of CI being 43%. After exclusion of three regions for insufficient volume (<200 LEBs), 13,945 LEB operations across 13 regions were available for regional analysis. Use of any type of intraoperative CI varied across regions from a low of 8% to a high of 70%, with angiography being performed most frequently. When CI was performed, the type of imaging modality varied between regions from a high of 99% for angiography to a high of 75% for duplex ultrasound. CI was more common in male patients (44% of male patients vs 42% of female patients; P = .032), diabetics (44% of diabetic patients vs 42% of nondiabetic patients; P = .026), and patients with coronary artery disease (45% of patients with coronary artery disease vs 42% of patients with no coronary artery disease; P = .0015). CI was performed less frequently in LEB using single-segment great saphenous vein vs LEB using lesser saphenous, arm, or composite vein (48% vs 57%; P < .0001). CI was used in 51% of LEBs with a tibial or pedal target vessel vs 38% of LEBs with a more proximal target vessel (P < .0001). Patients with an indication of critical limb ischemia underwent CI in 45% of LEBs vs 39% with an indication other than critical limb ischemia (P < .0001). Within the VQI database, considerable practice pattern variation exists in the use of CI. Currently, CI is most commonly employed for patients with critical limb ischemia, infrageniculate target vessel, and disadvantaged venous conduit. Further study is required to standardize and to define the appropriate use of CI for LEBs.

Effect of in-hospital physical activity on cardiovascular prognosis in lower extremity bypass for claudication.

[Purpose] This study aimed to evaluate the effect of in-hospital physical activity on patient prognosis after lower extremity bypass surgery for peripheral arterial disease. [Subjects and Methods] A total of 13 patients (16 limbs; 11 males and 2 females; mean age [standard deviation], 72.8 [5.9] years) who underwent lower extremity bypass surgery for Fontaine stage 2 peripheral arterial disease were included in this study and assigned to either an active group (n = 6) to perform increased physical activity after surgery or an inactive group (n = 7) to perform decreased physical activity after surgery. Daily in-hospital physical activity levels were measured continuously with a triaxial accelerometer. The occurrence of adverse cardiovascular events within a 2 year follow-up period was compared between groups. [Results] At discharge, the patients in the active group were able to walk more steps daily than those in the inactive group. The incidence of adverse events was 16.7% in the active group and 71.4% in the inactive group. [Conclusion] A higher in-hospital physical activity level was associated with a better long-term prognosis after lower extremity bypass surgery in patients with peripheral arterial disease.

The impact of infrainguinal endovascular interventions on the results of subsequent femoro-tibial bypass procedures: A retrospective cohort study

Background: Endovascular recanalization has become the accepted first-line treatment strategy for most lower extremity arterial occlusions, especially in patients with critical limb ischemia (Rutherford 4–6). Prior endovascular interventions have been described as risk factors for the outcome of subsequent lower extremity bypass surgery. The effect on subsequent tibial and peroneal bypasses is controversial. We analyzed the impact of prior endovascular lower extremity revascularization procedures on the short- and mid-term results of femoro-tibial and femoro-peroneal bypasses. Methods: A retrospective analysis was conducted of all patients who had undergone tibial or peroneal bypass surgery after prior endovascular interventions (PEI-Group, n = 40) of the same extremity in our department from October 2007 to October 2012. We compared this group with a group of patients who had received a tibial or peroneal bypass as primary revascularization procedure (BF-Group, n = 93) during the same period of time because primary endovascular therapy had been deemed unfeasible in those cases. Indication in all cases was critical limb ischemia; the median age was 78 years (range 50–90 years), 45.1% were diabetics, and 42.9% were female. The graft material was autologous vein in 80 cases and HePTFE in 53 cases. Endpoints of the analysis were primary and secondary patency rates, limb salvage and survival at 2 years postoperatively. Results: At 2 years overall primary patency was 68.4%, secondary patency was 69.5%, limb salvage was 83.6% and survival was 62.6%. Primary patency for the BF-Group was 74.3% vs. 55.1% for the PEI-Group (P = .310) at 2 years; secondary patency was 74.6% vs. 59.1% (P = .268). Prior endovascular intervention did not have any significant effects on limb salvage (83.7% vs. 83.6%; P = .470) or survival rates (61.0% vs. 65.0%; P = .258) at the 2-year mark, either. There were no significant differences in graft occlusion, death and major amputation rates within the first 30 postoperative days. Except for male gender, there were no significant differences in risk factors and indications between the two groups. Conclusions: Prior endovascular intervention of femoro-tibial vessels does not have a negative impact on the outcome of subsequent tibial or peroneal bypass surgery in patients with critical limb ischemia.

Clinical outcome after infrapopliteal bypass surgery in chronic hemodialysis patients with critical limb ischemia

Lower extremity bypass surgery has been widely performed to treat critical limb ischemia (CLI) in patients on hemodialysis (HD). However, the clinical outcome still remains unclear. We investigated the limb salvage rate after infrapopliteal bypass surgery in HD patients with CLI. From April 2006 to January 2013, 226 patients with 236 limbs who electively underwent bypass surgery for treatment of CLI due to infrapopliteal disease were enrolled. Patients were grouped by those who were on HD (n = 177) and those who were not (n = 49). They were monitored for 5 years or until December 2013 if the follow-up period was <5 years. Amputation-free survival, defined as freedom from major amputation or all-cause death, was primarily evaluated. Incidence of reintervention was also analyzed. Ulcer/gangrene was present in 206 patients (91.2%), and 233 limbs (98.7%) were treated using autogenous vein. Age was younger (67 ± 9 vs 72 ± 9 years; P = .0011) and ulcer/gangrene was more prevalent (93.8% vs 81.6%, P = .0080) in HD patients than in non-HD patients. During the follow-up period (median, 28 months), 33 (14.6%) major amputations and 28 reinterventions (12.4%) occurred, and 65 patients (28.8%) died. The 5-year amputation-free survival rate was significantly lower in HD patients than in non-HD patients (43.6% vs 78.8%, P = .0033), and the adjusted hazard ratio (HR) for amputation or death for HD patients was 2.36 (95% confidence interval [CI], 1.13-4.92; P = .022). Compared with non-HD patients, the status of HD was similarly an independent risk of major amputation (72.4% vs 92.5%; adjusted HR, 4.36; 95% CI, 1.04-18.3; P = .045) and mortality (56.9% vs 83.2%; adjusted HR, 2.81; 95% CI, 1.30-6.09; P = .0085). However, freedom from reintervention was comparable between the two groups (84.3% vs 86.8%; P = .89). In HD patients, body mass index (HR, 0.86; 95% CI, 0.76-0.96; per 1 kg/m(2) increase; P = .014) and C-reactive protein (HR, 1.06; 95% CI, 1.01-1.11; P = .014) independently predicted major amputation. Elevated C-reactive protein levels were also associated with death (HR, 1.04; 95% CI, 1.01-1.09; P = .047). The clinical outcome after infrapopliteal bypass surgery was poorer in HD patients with CLI compared with non-HD patients. Malnutrition or chronic inflammation was associated with poor outcome in HD patients with CLI due to infrapopliteal occlusive disease.

TCT-545 Contemporary Safety and Effectiveness of Peripheral Endovascular Interventions and Lower Extremity Bypass Surgery in the Treatment of Symptomatic Peripheral Arterial Disease

Treatment for symptomatic peripheral arterial disease (PAD) includes peripheral endovascular interventions (PVI) and lower extremity bypass surgery (LEB). Limited comparative effectiveness data exists between the two therapies. 1858 patients from two large integrated healthcare systems undergoing

Endoscopic Vein Harvesting in Lower Extremity Arterial Bypass: A Systematic Review

Endoscopic vein harvesting (EVH) for arterial bypass surgery may be associated with lower wound complication rates than open vein harvesting (OVH), but other long-term outcomes remain controversial, and there are concerns that graft patency may be poorer after EVH compared with OVH. We conducted a systematic review of all available evidence for EVH in lower extremity arterial bypass (LEAB). A literature search of Medline, Embase, Ovid and Cochrane databases between 1996 and 2013 was performed using the terms “endoscopic vein harvesting”, “minimally invasive vein harvest”, “peripheral bypass surgery”, and “lower extremity bypass surgery”, and detailed in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Primary outcomes were graft patency and overall wound complication rates. Secondary outcomes were wound infection, length of hospital stay, and cost-effectiveness. Summary estimates were calculated by random effects meta-analysis if sufficient data were available. We identified 18 cohort studies and case series, with considerable clinical heterogeneity, including 2,343 patients. Meta-analysis of six studies revealed a significantly reduced rate of primary patency after EVH (hazard ratio 1.29, 95% confidence interval [CI] 1.03-1.63), with no significant difference between EVH and OVH with respect to wound infection in 12 studies (odds ratio 0.81, 95% CI 0.61-1.08). There was a lack of strong evidence to support the secondary outcomes of EVH. EVH reduces primary patency rates after LEAB, but does not demonstrate an advantage with respect to postoperative wound complications. However, the available data are heterogeneous, and uncertainty is introduced by both evolution in technology and increasing technical experience. EVH should be used with caution and in the context of formal research.

Composite Measures for Profiling Hospitals on Surgical Morbidity

Although risk-adjusted morbidity is widely used as a surgical quality indicator, it may not always be a reliable indicator of hospital quality. In this study, we assess the value of a novel composite measure for improving the reliability of hospital morbidity rankings. Using data from the American College of Surgeons' National Surgical Quality Improvement Program (ACS-NSQIP), we studied all patients undergoing 4 surgical procedures (2008-2009): colectomy, ventral hernia repair, abdominal aortic aneurysm repair, and lower extremity bypass surgery. For these procedures, we created a composite measure by combining quality indicators from several distinct domains of quality: morbidity, reoperation, length of stay, and morbidity with other potentially related procedures. We empirically weighted each measure and adjusted for reliability using empirical Bayes techniques. To validate this approach, we assessed how well composite measures from 1 year (2008) predict morbidity in the next year (2009) compared with the standard ACS-NSQIP approach for assessing hospital rates of risk-adjusted morbidity. For all 4 operations, the composite measures explained a higher proportion of hospital-level variation in morbidity than the standard approach: ventral hernia repair (58% for the composite vs 8% for the standard approach), colon resection (33% vs 14%), abdominal aortic aneurysm repair (51% vs 38%), and lower extremity bypass surgery (32% vs 3%). When evaluating the ability to discriminate future performance, the composite approach performed best for ventral hernia repair. For this procedure, the bottom 20% of hospitals based on the composite approach had nearly threefold higher (odds ratio: 2.65; 95% confidence interval: 1.83-3.85) morbidity rates than the top 20% of hospitals. However, when using the standard approach, there was only a 1.3-fold difference (odds ratio: 1.30; 95% confidence interval: 0.87-1.96). Although the differences were smaller in magnitude, the composite measure also outperformed the standard approach for the other 3 procedures. Composite measures better reflect hospital quality than simple rates of risk-adjusted morbidity. In the context of ACS-NSQIP, composite measures would give hospitals a better sense of where they stand and help identify truly exemplary hospitals for benchmarking.

Outcomes following lower extremity bypass surgery among octogenarians

Outcomes following lower extremity bypass surgery among octogenarians

The impact of diabetes on postoperative outcomes following lower-extremity bypass surgery

The effect of diabetes type (noninsulin dependent vs insulin dependent) on outcomes after lower-extremity bypass (LEB) has not been clearly defined. Therefore, we analyzed associations between diabetes type and outcomes after LEB in patients with critical limb ischemia. We performed a retrospective analysis of 1977 infrainguinal LEB operations done for critical limb ischemia between 2003 and 2010 within the Vascular Study Group of New England. Patients were categorized as nondiabetic (ND), noninsulin-dependent diabetic (NIDD), or insulin-dependent diabetic (IDD) based on their preoperative medication regimen. Our main outcome measures were in-hospital mortality and major adverse events (MAEs)--a composite outcome, including myocardial infarction, dysrhythmia, congestive heart failure, wound infection, renal insufficiency, and major amputation. We compared crude and adjusted rates of mortality and MAEs using logistic regression across diabetes categories. Overall, 41% of patients were ND, 28% were NIDD, and 31% were IDD. Crude rates of in-hospital mortality were similar across these groups (1.7% vs 3.1% vs 2.1%; P = .211). Adjusted analyses accounting for differences in patient characteristics showed that diabetes is not associated with increased risk of in-hospital mortality. However, type of diabetes was associated with a higher risk of MAEs in both crude (15.1% for ND; 21.1% for NIDD; and 25.2% for IDD; P < .001) and adjusted analyses (odds ratio for NIDD, 1.41; 95% confidence interval, 1.2-1.7; odds ratio for IDD, 1.53; 95% confidence interval, 1.3-1.8). Diabetes is a significant contributor to the risk of postoperative complications after LEB surgery, and insulin dependence is associated with higher risk. Quality measures aimed at limiting complications after LEB may have the most impact if these initiatives are focused on patients who are IDD.

An integrated biochemical prediction model of all-cause mortality in patients undergoing lower extremity bypass surgery for advanced peripheral artery disease

Patients with advanced peripheral artery disease (PAD) have a high prevalence of cardiovascular (CV) risk factors and shortened life expectancy. However, CV risk factors poorly predict midterm (<5 years) mortality in this population. This study tested the hypothesis that baseline biochemical parameters would add clinically meaningful predictive information in patients undergoing lower extremity bypass operations. This was a prospective cohort study of patients with clinically advanced PAD undergoing lower extremity bypass surgery. The Cox proportional hazard model was used to assess the main outcome of all-cause mortality. A clinical model was constructed with known CV risk factors, and the incremental value of the addition of clinical chemistry, lipid assessment, and a panel of 11 inflammatory parameters was investigated using the C statistic, the integrated discrimination improvement index, and Akaike information criterion. The study monitored 225 patients for a median of 893 days (interquartile range, 539-1315 days). In this study, 50 patients (22.22%) died during the follow-up period. By life-table analysis (expressed as percent surviving ± standard error), survival at 1, 2, 3, 4, and 5 years, respectively, was 90.5% ± 1.9%, 83.4% ± 2.5%, 77.5% ± 3.1%, 71.0% ± 3.8%, and 65.3% ± 6.5%. Compared with survivors, decedents were older, diabetic, had extant coronary artery disease, and were more likely to present with critical limb ischemia as their indication for bypass surgery (P < .05). After adjustment for the above, clinical chemistry and inflammatory parameters significant (hazard ratio [95% confidence interval]) for all-cause mortality were albumin (0.43 [0.26-0.71]; P = .001), estimated glomerular filtration rate (0.98 [0.97-0.99]; P = .023), high-sensitivity C-reactive protein (hsCRP; 3.21 [1.21-8.55]; P = .019), and soluble vascular cell adhesion molecule (1.74 [1.04-2.91]; P = .034). Of the inflammatory molecules investigated, hsCRP proved most robust and representative of the integrated inflammatory response. Albumin, eGFR, and hsCRP improved the C statistic and integrated discrimination improvement index beyond that of the clinical model and produced a final C statistic of 0.82. A risk prediction model including traditional risk factors and parameters of inflammation, renal function, and nutrition had excellent discriminatory ability in predicting all-cause mortality in patients with clinically advanced PAD undergoing bypass surgery.

Composite Measures for Assessing Hospital Quality With Lower Extremity Bypass Surgery

Introduction: Risk-adjusted morbidity rates are widely used as surgical quality indicators for vascular surgery. However, since many hospitals have low caseloads, morbidity rates can be unreliable. We evaluated whether a novel approach for creating composite quality measures can improve the reliability of hospital morbidity reporting. Methods: Using data from ACS-NSQIP, we studied all patients undergoing major general and vascular surgery in 2008. for lower extremity bypass surgery, we created a composite measure by combining quality indicators from several distinct domains of quality: morbidity, reoperation, length of stay, and hospital morbidity with other potentially related procedures.

An Integrated Biochemical Prediction Model of All-Cause Mortality in Patients Undergoing Lower Extremity Bypass Surgery for Advanced Peripheral Artery Disease

Background: Patients with advanced peripheral artery disease (PAD) have a high prevalence of cardiovascular (CV) risk factors and shortened life expectancy. However, CV risk factors poorly predict midterm (<5 years) mortality in this population. This study tested the hypothesis that baseline biochemical parameters would add clinically meaningful predictive information in patients undergoing lower extremity bypass operations. Methods: This was a prospective cohort study of patients with clinically advanced PAD undergoing lower extremity bypass surgery. The Cox proportional hazard model was used to assess the main outcome of all-cause mortality. A clinical model was constructed with known CV risk factors, and the incremental value of the addition of clinical chemistry, lipid assessment, and a panel of 11 inflammatory parameters was investigated using the C statistic, the integrated discrimination improvement index, and Akaike information criterion. Results: The study monitored 225 patients for a median of 893 days (interquartile range, 539-1315 days). In this study, 50 patients (22.22%) died during the follow-up period. By life-table analysis (expressed as percent surviving standard error), survival at 1, 2, 3, 4, and 5 years, respectively, was 90.5% 1.9%, 83.4% 2.5%, 77.5% 3.1%, 71.0% 3.8%, and 65.3% 6.5%. Compared with survivors, decedents were older, diabetic, had extant coronary artery disease, and were more likely to present with critical limb ischemia as their indication for bypass surgery (P < .05). After adjustment for the above, clinical chemistry and inflammatory parameters significant (hazard ratio [95% confidence interval]) for all-cause mortality were albumin (0.43 [0.26-0.71]; P .001), estimated glomerular filtration rate (0.98 [0.97-0.99]; P .023), high-sensitivity C-reactive protein (hsCRP; 3.21 [1.21-8.55]; P .019), and soluble vascular cell adhesion molecule (1.74 [1.04-2.91]; P .034). Of the inflammatory molecules investigated, hsCRP proved most robust and representative of the integrated inflammatory response. Albumin, eGFR, and hsCRP improved the C statistic and integrated discrimination improvement index beyond that of the clinical model and produced a final C statistic of 0.82. Conclusions: A risk prediction model including traditional risk factors and parameters of inflammation, renal function, and nutrition had excellent discriminatory ability in predicting all-cause mortality in patients with clinically advanced PAD undergoing bypass surgery. (J Vasc Surg 2012;56:686-95.)

Socioeconomic Position Is Not Associated With 30-Day or 1-Year Mortality in Demographically Diverse Vascular Surgery Patients

Disparities in outcomes after surgical procedures have been attributed to race, sex, use of private insurance, and socioeconomic position (SEP). The purpose of this study was to determine the impact of SEP on mortality after lower-extremity bypass (LEB) surgery in a diverse patient population with extremes of SEP. Analysis of an electronic medical database. A tertiary care hospital in a demographically diverse section of a large metropolitan area. Six hundred nine (158 white men, 156 nonwhite men, 100 white women, and 195 non-white women) patients undergoing infrarenal lower-extremity arterial bypass surgery from July 1, 2002, to December 31, 2007. SEP was estimated using data from the 2000 US Census. The effects of race, sex, various comorbidities, the Revised Cardiac Risk Index, American Society of Anesthesiologists physical status, use of private insurance, indication for bypass surgery, and SEP on all-cause mortality was analyzed. SEP differed significantly among the 4 race-sex groups, with white men having the highest position (mean = 2.38) and non-white men having the lowest position (mean = -3.02). There was no statistically significant association in 30-day mortality among race-sex groups or with SEP. One-year mortality differed significantly between men and women for the entire cohort (13.7% and 24.1%, respectively; p < 0.01) but not among race groups or SEP. Disparities in SEP are not associated with short- or long-term mortality after LEB surgery. Other comorbid risk factors are more important when determining outcomes and should be the focus of interventions to improve outcomes.