Comparison of major adverse event rates after elective endovascular aneurysm repair in New England using a novel measure of complication severity.

OBJECTIVE: Major adverse event (MAE) rates are used as an outcome measure after surgical procedures. Although MAE rates summarize the occurrences of adverse events, they do not reflect differences in severity of these events. We propose that a measure of complication severity could provide a more accurate assessment about the quality of care. We aimed to analyze and to describe the regional variation in elective endovascular aneurysm repair (EVAR) MAE rates across centers in the Vascular Study Group of New England and to create an index for describing complication severity. METHODS: Patients undergoing elective EVAR (n = 4731) at 30 Vascular Study Group of New England centers between 2003 and 2016 were studied. The MAE composite end point was defined as the occurrence of any of the following postoperative events: myocardial infarction, dysrhythmia, congestive heart failure, leg ischemia, renal insufficiency, bowel complication, reoperation, surgical site infection, stroke, respiratory complication, and no home discharge. An adjustment factor (complication severity index) was calculated as a ratio of length of stay for complicated to uncomplicated cases. Multivariate logistic regression was used to calculate predicted MAE rates. The observed and predicted MAE rates as well as complication severity index rates were compared among centers and across quintiles of center volume. RESULTS: Observed MAE rates varied widely, ranging from 0% to 39%. Multivariate predictors of MAE included abdominal aortic aneurysm diameter >6 cm (odds ratio [OR], 2.1; 95% confidence interval [CI], 2.0-2.3), female sex (OR, 2.0; 95% CI, 1.8-2.2), chronic renal insufficiency (OR, 1.9; 95% CI, 1.7-2.1), age >75 years (OR, 1.9; 95% CI, 1.8-2.1), congestive heart failure (OR, 1.7; 95% CI, 1.5-1.9), chronic obstructive pulmonary disease (OR, 1.5; 95% CI, 1.4-1.6), diabetes (OR, 1.4; 95% CI, 1.1-1.7), positive stress test result (OR, 1.2; 95% CI, 1.1-1.4), preoperative beta blocker (OR, 1.2; 95% CI, 1.1-1.3), and no preoperative statin (OR, 1.2; 95% CI, 1.1-1.3). Predicted MAE rates had little variation (range, 21%-29%). In comparing observed MAE rates and complication severity, there was an inverse relation between the two, suggesting that although certain centers had a greater number of MAEs, the complications were less severe. CONCLUSIONS: MAE rates after elective EVAR vary widely. However, centers with higher MAE rates tended to have less severe complications, suggesting that observed MAE rates may not be a good measure of outcomes assessment after elective EVARs.

Behavioral Risk Factors and Regional Variation in Cardiovascular Health Care and Death.

INTRODUCTION: Reducing the burden of death from cardiovascular disease includes risk factor reduction and medical interventions. METHODS: This was an observational analysis at the hospital service area (HSA) level, to examine regional variation and relationships between behavioral risks, health services utilization, and cardiovascular disease mortality (the outcome of interest). HSA-level prevalence of cardiovascular disease behavioral risks (smoking, poor diet, physical inactivity) were calculated from the Behavioral Risk Factor Surveillance System; HSA-level rates of stress tests, diagnostic cardiac catheterization, and revascularization from a statewide multi-payer claims data set from Maine in 2013 (with 606,260 patients aged ≥35 years), and deaths from state death certificate data. Analyses were done in 2016. RESULTS: There were marked differences across 32 Maine HSAs in behavioral risks: smoking (12.4%-28.6%); poor diet (43.6%-73.0%); and physical inactivity (16.4%-37.9%). After adjustment for behavioral risks, rates of utilization varied by HSA: stress tests (28.2-62.4 per 1,000 person-years, coefficient of variation=17.5); diagnostic cardiac catheterization (10.0-19.8 per 1,000 person-years, coefficient of variation=17.3); and revascularization (4.6-6.2 per 1,000 person-years; coefficient of variation=9.1). Strong HSA-level associations between behavioral risk factors and cardiovascular disease mortality were observed: smoking (R2=0.52); poor diet (R2=0.38); and physical inactivity (R2=0.35), and no association between revascularization and cardiovascular disease mortality after adjustment for behavioral risk factors (R2=0.02). HSA-level behavioral risk factors were also strongly associated with all-cause mortality: smoking (R2=0.57); poor diet (R2=0.49); and physical inactivity (R2=0.46). CONCLUSIONS: There is substantial regional variation in behavioral risks and cardiac utilization. Behavioral risk factors are associated with cardiovascular disease mortality regionally, whereas revascularization is not. Efforts to reduce cardiovascular disease mortality in populations should focus on prevention efforts targeting modifiable risk factors.

Effect of adjunct femoral endarterectomy in lower extremity bypass on perioperative and 1-year outcomes.

BACKGROUND: Isolated common femoral endarterectomy was recently reported to have a 30-day mortality of 3.4%. The effect of adjunctive femoral endarterectomy at the time of lower extremity bypass is not well described, and therefore, the purpose of this study was to determine its associated perioperative and long-term risk. METHODS: Vascular Study Group of New England registry data were used to identify patients undergoing initial lower extremity bypass from 2003 to 2015. After univariate analysis, multivariable logistic regression was used to identify the independent association of endarterectomy with adverse perioperative events. Kaplan-Meier and Cox hazard models were used for the 1-year analysis. RESULTS: After exclusions, 4496 patients were identified as undergoing infrainguinal bypass (33% with endarterectomy). There was no difference in the proportion with chronic limb-threatening ischemia (CLI; 68% vs 67%; P = .24) or tissue loss of those with CLI (65% vs 63%; P = .34) between the adjunctive endarterectomy group and bypass alone, respectively. Patients undergoing adjunctive endarterectomy were older (mean 68 years vs 67 years; P = .02), more likely white (95% vs 93%; P = .02), smokers (91% vs 87%; P = .001), and more often had prior coronary artery bypass grafting/percutaneous coronary intervention (34% vs 31%; P = .02). The endarterectomy cohort had similar 30-day mortality (CLI: 2.6% vs 2.9%; P = .60; claudication: 0.2% vs 0.4%; P = 1.0) despite a longer operative time (median, 268 minutes vs 210 minutes; P < .001) and increased blood loss (median, 250 mL vs 180 mL; P < .001). Patients with CLI undergoing adjunctive endarterectomy had more in-hospital myocardial infarctions (MIs; 6.2% vs 3.8%; P = .003) and transfusions (11% vs 6.8%; P < .001). At 1-year, this group had a suggestion of improved freedom from major amputation (91% vs 87%; P = .049) and amputation-free survival (80% vs 76%; P = .03) that did not reach significance after adjustment. For patients with claudication and adjunctive endarterectomy, rates of MI (2.4% vs 0.9%; P = .02), renal dysfunction (3.6% vs 1.4%; P = .01), surgical site infection (SSI; 5.0% vs 2.6%; P = .02), and transfusion (4.6% vs 1.8%; P = .002) were higher. After adjustment, all patients undergoing adjunctive endarterectomy were at increased risk of MI (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.1-2.2), SSI (OR, 1.5; 95% CI, 1.1-2.0), and bleeding requiring transfusion (OR, 1.8; 95% CI, 1.4-2.3). There were no differences in 1-year survival for CLI or claudication groups and no difference in all 1-year end points for patients with claudication. CONCLUSIONS: Adjunctive femoral endarterectomy with bypass is safe, with no difference in perioperative or 1-year mortality compared with bypass. However, surgeons should be aware that adjunctive endarterectomy is associated with an increased risk of bleeding, SSI, and MI, likely from these patients' disease burden and presumed more extensive atherosclerosis.

Predicting Mortality of Ruptured Abdominal Aortic Aneurysms in the Era of Endovascular Repair.

BACKGROUND: Previous risk prediction models of mortality after ruptured abdominal aortic aneurysm (rAAA) repair have been limited by imprecision, complexity, or inclusion of variables not available in the preoperative setting. Most importantly, these prediction models have been derived and validated before the adoption of endovascular aneurysm repair (EVAR) as a treatment for rAAA. We sought to derive and validate a new risk-prediction tool using only easily obtainable preoperative variables in patients with rAAA who are being considered for repair in the endovascular era. METHODS: We used the Vascular Study Group of New England (VSGNE) database to identify all patients who underwent repair of RAAA (2006-2015). Variables were entered into a multivariable logistic regression model to identify independent predictors of 30-day mortality. Linear regression was then used to develop an equation to predict risk of 30-day mortality. RESULTS: During the study period, 649 patients underwent repair of rAAA; of these, 247 (38.1%) underwent EVAR and 402 (61.9%) underwent an open repair. The overall mortality associated with rAAA was 30.7% (open, 33.4% and EVAR, 26.2%). On multivariate modeling, the primary determinants of 30-day mortality were advanced age (>76 vs. ≤76 years, odds ratio [OR] = 2.91 and CI: 2.0-4.24), elevated creatinine (>1.5 mg/dL vs. ≤1.5 mg/dL, OR = 1.57 and CI: 1.05-2.34), and lowest systolic blood pressure (SBP) (BP <70 mm Hg vs. ≥70 mm Hg, OR = 2.65 and CI: 1.79-3.92). The logistic regression model had an area under a c-statistic of 0.69. The corresponding linear model used to provide a point estimate of 30-day mortality (%) was % mortality = 14 + 22 * (age >76) + 9 * (creatinine >1.5) + 20 * (bp <70) Using this model, patients can be stratified into different groups, each with a specific estimated risk of 30-day mortality ranging from a low of 14% to a high of 65%. CONCLUSIONS: In the endovascular era where both open and endovascular treatment are offered for the treatment of rAAA three variables, easily obtained in an emergency setting, accurately predict 30-day mortality for patients operated on for rAAA. This simple risk prediction tool could be used as a point of care decision aid to help the clinician in counseling patients and their families on treatment of those presenting with rAAA.

Determinants of Follow-Up Failure in Patients Undergoing Vascular Surgery Procedures.

BACKGROUND: The Vascular Study Group of New England (VSGNE) requires documentation of follow-up for >80% of patients at least 9 months postprocedure. However, many participating groups fall short of this goal. We sought to identify factors independently associated with loss to long-term follow-up (LTF). METHODS: The VSGNE was queried from 2008 to 2012, for all carotid endarterectomy (CEA), endovascular aneurysm repair (EVAR), open abdominal aortic aneurysm repair (OPEN), infrainguinal bypass (INFRA), and suprainguinal bypass (SUPRA) procedures in patients who survived greater than 9 months postprocedure. Our primary endpoint was loss to LTF, with LTF defined as documentation of a phone call or office visit ≥9 months postprocedure. Multivariable logistic regression was used to identify independent predictors of loss to LTF. Covariates included patient and procedural characteristics, and treatment center/physician. Relative contributions of covariates to the model were assessed by evaluation of the relative model Wald chi-squared values. RESULTS: We identified 14,452 procedures (6567 CEA, 2391 EVAR, 3356 INFRA, 979 OPEN, and 1159 SUPRA). Of those, 4669 (32%) were lost to LTF. Rates of loss to LTF varied by center, and ranged from 9.8% to 100%. Independent predictors of loss to LTF were history of coronary artery disease or percutaneous coronary artery intervention (odds ratio [OR] 1.4, 95% confidence interval [CI] 1.1-1.7), procedure type (OPEN, OR 1.4, 95% CI: 1.2-1.7; CEA, OR 1.2, 95% CI: 1.1-1.4; referent, EVAR), and discharge to rehab (OR 1.2, 95% CI: 1.1-1.4; referent, home). Center variation was the strongest determinant of loss to LTF with a model χ2 over 40 times as large as the second strongest determinant. CONCLUSIONS: LTF is central to outcome reporting and is vital to the success of any registry effort. In the VSGNE experience, center variation is the strongest predictor of loss to LTF, outweighing patient and procedural factors. Other predictors of loss to LTF included history of coronary revascularization, procedure type, no prior history of congestive heart failure, and discharge location. High performing centers likely have specific process measures that decrease loss to LTF. As the Society for Vascular Surgery Vascular Quality Initiative continues to roll out nationally, high performing centers in VSGNE should be studied to document and propagate best practices for minimizing loss to LTF.

Effect of chronic oral anticoagulation with warfarin on the durability and outcomes of endovascular aortic aneurysm repair.

OBJECTIVE: Endoleak after endovascular aortic aneurysm repair (EVAR) can affect the durability of the repair and lead to continued sac expansion, rupture, and the need for further endovascular or open surgical interventions. The purpose of this study was to determine whether chronic anticoagulation therapy with warfarin is associated with an increased incidence of endoleak and thus increased need for reintervention after EVAR. METHODS: We reviewed the records of 401 consecutive patients who underwent EVAR at a single institution from 2003 until 2011. Patients on warfarin were compared with a control group not on warfarin. Primary endpoints included reintervention, defined as rupture, explant, or angiography; death from any cause; and a composite outcome of reintervention or death. The presence of an endoleak at last follow-up, identified by computed tomography or ultrasound scan, and increase of more than 5 mm in aneurysm sac size were secondary endpoints. Cox proportional hazards models were used to estimate the effect of warfarin use on the primary and secondary outcomes, controlling for age, gender, obesity, specific comorbidities, antiplatelet drugs, statin use, and urgency of EVAR. RESULTS: Three hundred sixty-three patients with a median follow-up period of 29 months had sufficient data for analysis. Warfarin use was not associated with an increased risk of any of the primary endpoints. Controlling for covariates and length of observation via proportional hazards models, the effect of warfarin remained insignificant. It was found, however, on regression analysis, that adverse outcomes were more prevalent after emergency EVAR and in patients deemed unfit for open surgical repair. CONCLUSIONS: Chronic oral anticoagulation does not appear to affect the incidence of endoleak after EVAR, nor does it impact the need for reintervention or degree of sac regression. We feel that warfarin may be safely used in post-EVAR patients. It appears that adverse long-term outcomes are more likely after emergency EVAR and in patients deemed unfit for open surgery.

Endovascular stenting of ascending lumbar veins for refractory inferior vena cava occlusion.

Chronic inferior vena cava (IVC) occlusion is a debilitating disease process. Recently, endovascular techniques have been described using progressive balloon dilatation and stenting to treat IVC occlusion with reasonable success. We present two cases of endovascular dilatation and stenting of the ascending lumbar vein. This technique provided good early relief of symptoms with ulcer healing, decreased swelling, and decreased pain. To our knowledge this is the first report of endovascular therapy of IVC occlusion via stenting of the ascending lumbar vein. This technique may provide a feasible treatment option when the occluded IVC cannot be reopened.

Successful endovascular treatment of a ruptured internal iliac aneurysm.

Internal iliac artery aneurysms (IIAs) are rare but can be the source of considerable morbidity when rupture occurs. IIAs have traditionally been treated with direct surgical exclusion or ligation. More recently, the advent of endovascular techniques have been adapted to treat isolated common and IIAs in lieu of elective surgical correction. This case report describes an 81-year-old patient with multiple medical problems and a symptomatic IIA, initially diagnosed with computed tomographic scan. Arteriography results showed extravasation of contrast from a left IIA. The aneurysm was treated with endovascular exclusion, with multiple coils in the IIA followed by placement of a covered stent within the common and external iliacs to exclude the orifice of the IIA. The patient tolerated the procedure well, and at 2 months after the procedure, no endoleak was present on follow-up computed tomographic scan results. At 12 months postprocedure, the patient has remained well. This case shows that endovascular therapies may offer a good treatment option in symptomatic or ruptured IIA, particularly in a patient who is at poor operative risk.