Jeremy D. Darling

Long-Term Outcomes of Abdominal Aortic Aneurysm in the Medicare Population

BACKGROUND Randomized trials and observational studies have shown that perioperative morbidity and mortality are lower with endovascular repair of abdominal aortic aneurysm than with open repair, but the survival benefit is not sustained. In addition, concerns have been raised about the long-term risk of aneurysm rupture or the need for reintervention after endovascular repair. METHODS We assessed perioperative and long-term survival, reinterventions, and complications after endovascular repair as compared with open repair of abdominal aortic aneurysm in propensity-score-matched cohorts of Medicare beneficiaries who underwent repair during the period from 2001 through 2008 and were followed through 2009. RESULTS We identified 39,966 matched pairs of patients who had undergone either open repair or endovascular repair. The overall perioperative mortality was 1.6% with endovascular repair versus 5.2% with open repair (P<0.001). From 2001 through 2008, perioperative mortality decreased by 0.8 percentage points among patients who underwent endovascular repair (P=0.001) and by 0.6 percentage points among patients who underwent open repair (P=0.01). The rate of conversion from endovascular to open repair decreased from 2.2% in 2001 to 0.3% in 2008 (P<0.001). The rate of survival was significantly higher after endovascular repair than after open repair through the first 3 years of follow-up, after which time the rates of survival were similar. Through 8 years of follow-up, interventions related to the management of the aneurysm or its complications were more common after endovascular repair, whereas interventions for complications related to laparotomy were more common after open repair. Aneurysm rupture occurred in 5.4% of patients after endovascular repair versus 1.4% of patients after open repair through 8 years of follow-up (P<0.001). The rate of total reinterventions at 2 years after endovascular repair decreased over time (from 10.4% among patients who underwent procedures in 2001 to 9.1% among patients who underwent procedures in 2007). CONCLUSIONS Endovascular repair, as compared with open repair, of abdominal aortic aneurysm was associated with a substantial early survival advantage that gradually decreased over time. The rate of late rupture was significantly higher after endovascular repair than after open repair. The outcomes of endovascular repair have been improving over time. (Funded by the National Institutes of Health.).

Routine use of ultrasound-guided access reduces access site-related complications after lower extremity percutaneous revascularization

OBJECTIVE We sought to elucidate the risks for access site-related complications (ASCs) after percutaneous lower extremity revascularization and to evaluate the benefit of routine ultrasound-guided access (RUS) in decreasing ASCs. METHODS We reviewed all consecutive percutaneous revascularizations (percutaneous transluminal angioplasty or stent) performed for lower extremity atherosclerosis at our institution from 2002 to 2012. RUS began in September 2007. Primary outcome was any ASC (bleeding, groin or retroperitoneal hematoma, vessel rupture, or thrombosis). Multivariable logistic regression was used to determine predictors of ASC. RESULTS A total of 1371 punctures were performed on 877 patients (43% women; median age, 69 [interquartile range, 60-78] years) for claudication (29%), critical limb ischemia (59%), or bypass graft stenosis (12%) with 4F to 8F sheaths. There were 72 ASCs (5%): 52 instances of bleeding or groin hematoma, nine pseudoaneurysms, eight retroperitoneal hematomas, two artery lacerations, and one thrombosis. ASCs were less frequent when RUS was used (4% vs 7%; P = .02). Multivariable predictors of ASC were age >75 years (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.1-3.7; P = .03), congestive heart failure (OR, 1.9; 95% CI, 1.1-1.3; P = .02), preoperative warfarin use (OR, 2.0; 95% CI, 1.1-3.5; P = .02), and RUS (OR, 0.4; 95% CI, 0.2-0.7; P < .01). Vascular closure devices (VCDs) were not associated with lower rates of ASCs (OR, 1.1; 95% CI, 0.6-1.9; P = .79). RUS lowered ASCs in those >75 years (5% vs 12%; P < .01) but not in those taking warfarin preoperatively (10% vs 13%; P = .47). RUS did not decrease VCD failure (6% vs 4%; P = .79). CONCLUSIONS We were able to decrease the rate of ASCs during lower extremity revascularization with the implementation of RUS. VCDs did not affect ASCs. Particular care should be taken with patients >75 years old, those with congestive heart failure, and those taking warfarin.

The effect of endovascular treatment on isolated iliac artery aneurysm treatment and mortality

OBJECTIVE Isolated iliac artery aneurysms are rare, but potentially fatal. The effect of recent trends in the use of endovascular iliac aneurysm repair (EVIR) on isolated iliac artery aneurysm-associated mortality is unknown. METHODS We identified all patients with a primary diagnosis of iliac artery aneurysm in the National Inpatient Sample from 1988 to 2011. We examined trends in management (open vs EVIR, elective and urgent) and overall isolated iliac artery aneurysm-related deaths (with or without repair). We compared in-hospital mortality and complications for the subgroup of patients undergoing elective open and EVIR from 2000 to 2011. RESULTS We identified 33,161 patients undergoing isolated iliac artery aneurysm repair from 1988 to 2011, of which there were 9016 EVIR and 4933 open elective repairs from 2000 to 2011. Total repairs increased after the introduction of EVIR, from 28 to 71 per 10 million United States (U.S.) population (P < .001). EVIR surpassed open repair in 2003. Total isolated iliac artery aneurysm-related deaths, due to rupture or elective repair, decreased after the introduction of EVIR from 4.4 to 2.3 per 10 million U.S. population (P < .001). However, urgent admissions did not decrease during this time period (15 to 15 procedures per 10 million U.S. population; P = .30). Among elective repairs after 2000, EVIR patients were older (72.4 vs 69.4 years; P = .002) and were more likely to have a history of prior myocardial infarction (14.0% vs 11.3%; P < .001) and renal failure (7.2% vs 3.6%; P < .001). Open repair had significantly higher rate of in-hospital mortality (1.8% vs 0.5%; P < .001) and complications (17.9% vs 6.7%; P < .001) and a longer length of stay (6.7 vs 2.3 days; P < .001). CONCLUSIONS Treatment of isolated iliac artery aneurysms has increased since the introduction of EVIR and is associated with lower perioperative mortality, despite a higher burden of comorbid illness. Decreasing iliac artery aneurysm-attributable in-hospital deaths are likely related primarily to lower elective mortality with EVIR rather than rupture prevention.

Management and outcomes of isolated renal artery aneurysms in the endovascular era

OBJECTIVE Isolated renal artery aneurysms are rare, and controversy remains about indications for surgical repair. Little is known about the impact of endovascular therapy on selection of patients and outcomes of renal artery aneurysms. METHODS We identified all patients undergoing open or endovascular repair of isolated renal artery aneurysms in the Nationwide Inpatient Sample from 1988 to 2011 for epidemiologic analysis. Elective cases were selected from the period 2000 to 2011 to create comparable cohorts for outcome comparison. We identified all patients with a primary diagnosis of renal artery aneurysms undergoing open surgery (reconstruction or nephrectomy) or endovascular repair (coil or stent). Patients with concomitant aortic aneurysms or dissections were excluded. We evaluated patient characteristics, management, and in-hospital outcomes for open and endovascular repair, and we examined changes in management and outcomes over time. RESULTS We identified 6234 renal artery aneurysm repairs between 1988 and 2011. Total repairs increased after the introduction of endovascular repair (8.4 in 1988 to 13.8 in 2011 per 10 million U.S. population; P = .03). Endovascular repair increased from 0 in 1988 to 6.4 in 2011 per 10 million U.S. population (P < .0001). However, there was no concomitant decrease in open surgery (5.5 in 1988 to 7.4 in 2011 per 10 million U.S. population; P = .28). From 2000 to 2011, there were 1627 open and 1082 endovascular elective repairs. Patients undergoing endovascular repair were more likely to have a history of coronary artery disease (18% vs 11%; P < .001), prior myocardial infarction (5.2% vs 1.8%; P < .001), and renal failure (7.7% vs 3.3%; P < .001). In-hospital mortality was 1.8% for endovascular repair, 0.9% for open reconstruction (P = .037), and 5.4% for nephrectomy (P < .001 compared with all revascularization). Complication rates were 12.4% for open repair vs 10.5% for endovascular repair (P = .134), including more cardiac (2.2% vs 0.6%; P = .001) and peripheral vascular complications (0.6% vs 0.0%; P = .014) with open repair. Open repair had a longer length of stay (6.0 vs 4.6 days; P < .001). After adjustment for other predictors of mortality, including age (odds ratio [OR], 1.05 per decade; 95% confidence interval [CI], 1.0-1.1; P = .001), heart failure (OR, 7.0; 95% CI, 3.1-16.0; P < .001), and dysrhythmia (OR, 5.9; 95% CI, 2.0-16.8; P = .005), endovascular repair was still not protective (OR, 1.6; 95% CI, 0.8-3.2; P = .145). CONCLUSIONS More renal artery aneurysms are being treated with the advent of endovascular techniques, without a reduction in operative mortality or a reduction in open surgery. Indications for repair of renal artery aneurysms should be re-evaluated.

Perioperative outcome of endovascular repair for complex abdominal aortic aneurysms

Background: As endovascular aneurysm repair (EVAR) continues to advance, eligibility of patients with anatomically complex abdominal aortic aneurysms (AAAs) for EVAR is increasing. However, whether complex EVAR is associated with favorable outcome over conventional open repair and how outcomes compare with infrarenal EVAR remains unclear. This study examined perioperative outcomes of patients undergoing complex EVAR, focusing on differences with complex open repair and standard infrarenal EVAR. Methods: We identified all patients undergoing nonruptured complex EVAR, complex open repair, and infrarenal EVAR in the American College of Surgeons National Surgical Quality Improvement Program Targeted Vascular Module. Aneurysms were considered complex if the proximal extent was juxtarenal or suprarenal or when the Zenith Fenestrated endograft (Cook Medical, Bloomington, Ind) was used. Independent risks were established using multivariable logistic regression analysis. Results: Included were 4584 patients, with 411 (9.0%) undergoing complex EVAR, 395 (8.6%) undergoing complex open repair, and 3778 (82.4%) undergoing infrarenal EVAR. Perioperative mortality was 3.4% after complex EVAR, 6.6% after open repair (P = .038), and 1.5% after infrarenal EVAR (P = .005). Postoperative acute kidney injuries occurred in 2.3% of complex EVAR patients, in 9.5% of those undergoing complex open repair (P < .001), and in 0.9% of infrarenal EVAR patients (P = .007). Compared with complex EVAR, complex open repair was an independent predictor of 30‐day mortality (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.1‐4.4), renal function deterioration (OR, 4.8; 95% CI, 2.2‐10.5), and any complication (OR, 3.7; 95% CI, 2.5‐5.5). When complex vs infrarenal EVAR were compared, infrarenal EVAR was associated with favorable 30‐day mortality (OR, 0.5; 95% CI, 0.2‐0.9), and renal outcome (OR, 0.4; 95% CI, 0.2‐0.9). Conclusions: In this study assessing the perioperative outcomes of patients undergoing repair for anatomically complex AAAs, complex EVAR had fewer complications than complex open repair but carried a higher risk of adverse outcomes than infrarenal EVAR. Further research is warranted to determine whether the benefits of EVAR compared with open repair for complex AAA treatment are maintained during long‐term follow‐up.

Results for primary bypass versus primary angioplasty/stent for lower extremity chronic limb-threatening ischemia

Background: Long‐term results comparing percutaneous transluminal angioplasty with or without stenting (PTA/S) and open surgical bypass for chronic limb‐threatening ischemia (CLTI) in patients who have had no prior intervention are lacking. Methods: All patients undergoing a first‐time lower extremity revascularization for CLTI by vascular surgeons at our institution from 2005 to 2014 were retrospectively reviewed. Outcomes included perioperative complications, wound healing, restenosis, primary patency, reintervention, major amputation, RAS events (ie, reintervention, major amputation, or stenosis), and mortality. Outcomes were evaluated using χ2, Kaplan‐Meier, and Cox regression analyses. Results: Of the 2869 total lower extremity revascularizations performed between 2005 and 2014, there were 1336 that fit our criteria of a first‐time lower extremity intervention for CLTI (668 bypass procedures and 668 PTA/S procedures). Bypass patients were younger (71 vs 72 years; P = .02) and more often male (62% vs 56%; P < .02). Total mean hospital length of stay (LOS) was significantly longer after a first‐time bypass (10 vs 8 days; P < .001), as were mean preoperative LOS (4 vs 3 days; P < .01) and postoperative LOS (7 vs 5 days; P < .001). There was no difference in perioperative mortality (3% vs 3%; P = .63). Surgical site infection occurred in 10% of bypass patients. Freedom from reintervention was significantly higher in patients undergoing a first‐time bypass procedure (62% vs 52% at 3 years; P = .04), as was freedom from restenosis (61% vs 45% at 3 years; P < .001). Complete wound healing at 6‐month follow‐up was significantly better after an initial bypass (43% vs 36%; P < .01). A Cox regression model of all patients showed that reintervention was predicted by a first‐time PTA/S (hazard ratio, 1.6; 95% confidence interval, 1.3‐2.1) and both preoperative femoropopliteal TransAtlantic Inter‐Society Consensus (TASC) C and TASC D lesions (2.0 [1.3‐3.1] and 1.8 [1.3‐2.7], respectively). Major amputation among all patients was predicted by an initial presentation of gangrene (2.5 [1.3‐5.0]), dialysis dependence (1.9 [1.3‐2.9]), diabetes (2.0 [1.1‐3.8]), and preoperative femoropopliteal TASC D lesions (2.1 [1.1‐4.0]) and was not predicted by procedure type. Conclusions: In this retrospective analysis, bypass for the primary treatment of CLTI showed improved 6‐month wound healing, higher freedom from restenosis, improved patency rates, significantly fewer reinterventions, and higher survival than PTA/S within 3 years; however, a bypass‐first approach was associated with increased total hospital LOS and wound infection. Perioperative mortality and amputation rates were similar between procedure types.

Patient selection and perioperative outcomes are similar between targeted and nontargeted hospitals (in the National Surgical Quality Improvement Program) for abdominal aortic aneurysm repair

Objective: The targeted vascular module in the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) consists of self‐selected hospitals that choose to collect extra clinical details for better risk adjustment and improved procedure‐specific outcomes. The purpose of this study was to compare patient selection and outcomes between targeted and nontargeted hospitals in the NSQIP regarding the operative management of abdominal aortic aneurysm (AAA). Methods: We identified all patients who underwent endovascular aneurysm repair (EVAR) or open AAA repair from 2011 to 2013 and compared cases by whether the operation took place in a targeted or nontargeted hospital. EVAR and open repair as well as intact and ruptured aneurysms were evaluated separately. Only variables contained in both modules were used to evaluate rupture status and operation type. All thoracoabdominal aneurysms were excluded. Univariate analysis was performed for intact and ruptured EVAR and open repair grouped by complexity, defined as visceral involvement in open repair and a compilation of concomitant procedures for EVAR. Multivariable models were developed to identify effect of hospital type on mortality. Results: There were 17,651 AAA repairs identified. After exclusion of aneurysms involving the thoracic aorta (n = 352), there were 1600 open AAA repairs at targeted hospitals (21% ruptured) and 2725 at nontargeted hospitals (19% ruptured) and 4986 EVARs performed at targeted hospitals (6.7% ruptured) and 7988 at nontargeted hospitals (5.2% ruptured). There was no significant difference in 30‐day mortality rates between targeted and nontargeted hospitals for intact aneurysms (EVAR noncomplex, 1.8% vs 1.4% [P = .07]; open repair noncomplex, 4.2% vs 4.5% [P = .7]; EVAR complex, 5.0% vs 3.2% [P = .3]; open repair complex, 8.0% vs 6.0% [P = .2]). For ruptured aneurysms, again there was no difference in mortality between the targeted and nontargeted hospitals (EVAR noncomplex, 23% vs 25% [P = .4]; open repair noncomplex, 38% vs 34% [P = .2]; EVAR complex, 29% vs 33% [P = 1.0]; open repair complex, 27% vs 41% [P = .09]). Multivariable analysis further demonstrated that having an operation at a targeted vs nontargeted hospital had no impact on mortality for both intact and ruptured aneurysms (odds ratio, 1.1 [0.9‐1.4] and 1.0 [0.8‐1.3], respectively). Conclusions: This analysis highlights the similarities between targeted and nontargeted hospitals within the NSQIP for AAA operative management and suggests that data from the targeted NSQIP, in terms of AAA management, are generalizable to all NSQIP hospitals.

Adherence to lipid management guidelines is associated with lower mortality and major adverse limb events in patients undergoing revascularization for chronic limb-threatening ischemia

Objective: The 2013 American College of Cardiology/American Heart Association lipid management guidelines recommend high‐intensity statins for all patients ≤75 years old with chronic limb‐threatening ischemia (CLTI) and moderate‐intensity statins for CLTI patients >75 years old without contraindications or on dialysis, but these recommendations are based primarily on coronary and stroke data. We aimed to validate these guidelines in patients with CLTI and to assess current adherence to these recommendations. Methods: We identified all patients with CLTI who underwent first‐time revascularization (endovascular or surgical) at Beth Israel Deaconess Medical Center from 2005 to 2014. Patients were classified as taking high‐intensity, moderate‐intensity, low‐intensity, or no statin postoperatively. Outcomes included death and major adverse limb event (MALE). Propensity scores were calculated for the probability of receiving guideline‐recommended intensity of statin therapy to account for nonrandom assignment of treatments. Cox regression models were constructed and adjusted for the propensity scores and further adjusted for strong potential confounders. Results: After excluding patients on hemodialysis (n = 252), we identified 1019 limbs from 931 patients with a median follow‐up of 380 days. Patients discharged on the recommended statin intensity had higher rates of preoperative statin use, coronary artery disease, chronic kidney disease, stroke, atrial fibrillation, congestive heart failure, and coronary artery bypass grafting; they had lower smoking rates and were less likely to be ambulatory preoperatively. Overall, only 35% were taking the recommended statin dosage: 55% of those >75 years old and 20% of those ≤75 years old. In multivariable analysis including propensity scores where appropriate, discharge on any statin was associated with lower mortality (hazard ratio [HR], 0.71; 95% confidence interval [CI], 0.60‐0.90; P < .01). Discharge on the recommended intensity of statin therapy was associated with lower mortality (HR, 0.73; 95% CI, 0.60‐0.99; P < .05) and lower MALE rate (HR, 0.71; 95% CI, 0.51‐0.97; P < .05). Patients >75 years old and ≤75 years old accrued similar benefit. In patients >75 years old, moderate‐intensity statin therapy was associated with lower rates of death and MALE compared with high‐intensity therapy but did not reach statistical significance. Conclusions: Use of the recommended intensity of statin therapy in compliance with 2013 American College of Cardiology/American Heart Association lipid management guidelines is associated with significantly improved survival and lower MALE rate in patients undergoing revascularization for CLTI. Adherence to current guidelines is an appealing target for quality improvement.

Predictive ability of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system after first-time lower extremity revascularizations

Objective: The Society for Vascular Surgery (SVS) Wound, Ischemia and foot Infection (WIfI) classification system was proposed to predict 1‐year amputation risk and potential benefit from revascularization. Our goal was to evaluate the predictive ability of this scale in a real‐world selection of patients undergoing a first‐time lower extremity revascularization for chronic limb‐threatening ischemia (CLTI). Methods: From 2005 to 2014, 1336 limbs underwent a first‐time lower extremity revascularization for CLTI, of which 992 had sufficient data to classify all three WIfI components (wound, ischemia, and foot infection). Limbs were stratified into the SVS WIfI clinical stages (from 1 to 4) for 1‐year amputation risk estimation, a novel WIfI composite score from 0 to 9 (that weighs all WIfI variables equally), and a novel WIfI mean score from 0 to 3 (that can incorporate limbs missing any of the three WIfI components). Outcomes included major amputation; revascularization, major amputation, or stenosis (>3.5× step‐up by duplex; RAS) events; and death. Predictors were identified using Cox regression models and Kaplan‐Meier survival estimates. Results: Of the 1336 first‐time procedures performed, 992 limbs were classified in all three WIfI components (524 endovascular and 468 bypass; 26% rest pain and 74% tissue loss). Cox regression demonstrated that a one‐unit increase in the WIfI clinical stage increases the risk of major amputation (hazard ratio [HR], 2.4; 95% confidence interval [CI], 1.7–3.2) and RAS events in all limbs (HR, 1.2; 95% CI, 1.1–1.3). Separate models of the entire cohort, a bypass‐only cohort, and an endovascular‐only cohort showed that a one‐unit increase in the WIfI mean score is associated with an increase in the risk of major amputation (all three cohorts: HR, 5.3 [95% CI, 3.6–6.8], 4.1 [2.4–6.9], and 6.6 [3.8–11.6], respectively) and RAS events (all three cohorts: HR, 1.7 [95% CI, 1.4–2.0], 1.9 [1.4–2.6], and 1.4 [1.1–1.9], respectively). The novel WIfI composite and WIfI mean scores were the only consistent predictors of death among the three cohorts, with the WIfI mean score proving most strongly predictive in the entire cohort (HR, 1.4; 95% CI, 1.1–1.7), the bypass‐only cohort (HR, 1.5; 95% CI, 1.1–1.9), and the endovascular‐only cohort (HR, 1.4; 95% CI, 1.0–1.8). Although the individual WIfI wound component was able to predict mortality among all patients (HR, 1.1; 95% CI, 1.0–1.2) and bypass‐only patients (HR, 1.2; 95% CI, 1.1–1.3), neither the additional individual WIfI components nor the WIfI clinical stage were able to significantly predict mortality among any cohort. Conclusions: This study supports the ability of the SVS WIfI classification system to predict major amputation; however, the novel WIfI mean and WIfI composite scores predict amputation, RAS events, and mortality more consistently than any other current WIfI scoring system. The WIfI mean score allows inclusion of all limbs, and both novel scoring systems are easier to conceptualize, give equal weight to each WIfI component, and may provide clinicians more effective comparisons in outcomes between patients.

Regional variation in racial disparities among patients with peripheral artery disease

Objective: Prior studies identified significant racial disparities as well as regional variation in outcomes of patients with peripheral artery disease (PAD). We aimed to determine whether regional variation contributes to these racial disparities. Methods: We identified all white or black patients who underwent infrainguinal revascularization or amputation in 15 deidentified regions of the Vascular Quality Initiative between 2003 and 2017. We excluded three regions with <100 procedures. We used multivariable linear regression, allowing clustering at the hospital level to calculate the marginal effects of race and region on adjusted 30‐day mortality, major adverse limb events (MALEs), and amputation. We compared long‐term outcomes between black and white patients within each region and within patients of each race treated in different regions using multivariable Cox regression. Results: We identified 90,418 patients, 15,527 (17%) of whom were black. Patients underwent 31,263 bypasses, 52,462 endovascular interventions, and 6693 amputations. Black patients were younger and less likely to smoke, to have coronary artery disease, or to have chronic obstructive pulmonary disease, but they were more likely to have diabetes, limb‐threatening ischemia, dialysis dependence, and hypertension and to be self‐insured or on Medicaid (all P < .05). Adjusted 30‐day mortality ranged from 1.2% to 2.1% across regions for white patients and 0% to 3.0% for black patients; adjusted 30‐day MALE varied from 4.0% to 8.3% for white patients and 2.4% to 8.1% for black patients; and adjusted 30‐day amputation rates varied from 0.3% to 1.2% for white patients and 0% to 2.1% for black patients. Black patients experienced significantly different (both higher and lower) adjusted rates of 30‐day mortality and amputation than white patients did in several regions (P < .05) but not MALEs. In addition, within each racial group, we found significant variation in the adjusted rates of all outcomes between regions (all P < .01). In adjusted analyses, compared with white patients, black patients experienced consistently lower long‐term mortality (hazard ratio [HR], 0.80; 95% confidence interval [CI], 0.73‐0.88; P < .001) and higher rates of MALEs (HR, 1.15; 95% CI, 1.06‐1.25; P < .001) and amputation (HR, 1.33; 95% CI, 1.18‐1.51; P < .001), with no statistically significant variation across the regions. However, rates of all long‐term outcomes varied within both racial groups across regions. Conclusions: Significant racial disparities exist in outcomes after lower extremity procedures in patients with PAD, with regional variation contributing to perioperative but not long‐term outcome disparities. Underperforming regions should use these data to generate quality improvement projects, as understanding the etiology of these disparities is critical to improving the care of all patients with PAD.