Metformin Use and Long-term Outcomes Including Aneurysm Sac Dynamics Following EVAR for Infrarenal Abdominal Aortic Aneurysm: "A Retrospective Study".

PURPOSE: Metformin, widely used for the treatment of diabetes mellitus (DM), has shown potential for inhibiting abdominal aortic aneurysm (AAA) growth by reducing extracellular matrix remodeling and inflammation. However, its influence on clinical outcomes and aneurysm sac dynamics after endovascular aneurysm repair (EVAR) remains uncertain. This retrospective study aims to explore the effects of metformin on long-term outcomes following EVAR. MATERIALS AND METHODS: Patients who underwent elective standard EVAR for infrarenal AAA at a single academic Dutch hospital from 2000 to 2022 were included. We collected baseline patient demographics, comorbid conditions, anatomical and operative characteristics, and 30-day postoperative events. Metformin use was defined as using it preceding EVAR. The primary outcome, the postoperative aneurysm sac volume over time, was investigated using linear mixed-effects modeling. The secondary outcomes, 8-year all-cause mortality and freedom from graft-related events, were evaluated using Kaplan-Meier methods. RESULTS: We analyzed 685 patients, including 634 (93%) non-metformin users and 51 (7%) metformin users. The median follow-up period was similar (4.0 years [IQR=1.5, 6.5] vs 5.0 years [IQR=2.0, 8.0]; p=0.091). Patients on metformin had a preoperative aneurysm sac volume of 153 cc (IQR=114, 195) compared with 178 cc (IQR=133, 240) for non-metformin patients (p=0.054). At 30 days post-EVAR, metformin patients had a comparable mean aneurysm sac volume compared with non-metformin patients (metformin: -19.4 cc [95% confidence interval [CI]: -47.4, 8.5]; p=0.173). The effect of metformin on aneurysm growth over time was not significant (-3.9 cc/year; [95% CI: -22.7, 14.9]; p=0.685). Following risk-adjusted analysis, metformin use was associated with similar rates of all-cause mortality (metformin vs no metformin: 50% vs 44%; hazard ratio [HR]=1.11, 95% CI: 0.66, 1.88; p=0.688) and freedom from graft-related events (metformin vs no metformin: 63% vs 66%; HR=1.82, 95% CI: 0.98, 3.38; p=0.059). CONCLUSION: Although metformin use may reduce preoperative AAA growth, it does not seem to influence overall/long-term post-EVAR AAA sac dynamics, all-cause mortality, or freedom from graft-related events. These findings suggest that the potential protective effect of metformin on AAA may not be sustained after EVAR. Further prospective studies are needed to investigate the mechanisms underlying the potential role of metformin in AAA management following EVAR. CLINICAL IMPACT: There is currently no approved pharmacological treatment available to slow the abdominal aortic aneurysm (AAA) growth rate and reduce the related risk of rupture. In our retrospective analysis including 685 patients undergoing EVAR for infrarenal AAA, we found that metformin use was not associated with improved post-EVAR outcomes, such as a reduction of aneurysm sac volume over time, eight-year all-cause mortality, or freedom of graft-related events. These findings suggest that the potential protective effect of metformin on AAA may not be sustained after EVAR and underscore the need for ongoing research into this area.

Factors associated with in-hospital complications and long-term implications of these complications in elderly patients undergoing endovascular aneurysm repair.

OBJECTIVE: Perioperative complications in elderly patients undergoing endovascular aneurysm repair (EVAR) occur frequently. Although perioperative mortality has been well-described in the elderly patient population, factors associated with in-hospital complications and their impact on long-term survival remain poorly characterized. METHODS: We identified all patients undergoing elective EVAR for infrarenal AAA within the Vascular Quality Initiative registry (2003-2018) and compared in-hospital complication rates between elderly (age ≥75) and nonelderly patients (<75). We used logistic regression to identify independent factors associated with in-hospital complications, whereas Kaplan-Meier analysis and Cox proportional hazards models were used to determine associations between complications and long-term survival. To assess the effect of complications on early and late survival, we stratified survival periods into the first 30 days after discharge, and between 1 and 6 months, 7 and 12 months, and 1 and 8 years after the index procedure. To investigate the implications of in-hospital morbidity on long-term outcomes, we estimated the adjusted population-attributable fractions of individual complications on both perioperative and long-term survival. RESULTS: We identified 17,156 elderly patients and 19,922 nonelderly patients. Elderly patients experienced higher complication rates compared with nonelderly patients (17% vs 10%; P < .001). The factors with the strongest associations with morbidity in elderly patients were anemia (odds ratio [OR], 2.4; 95% confidence interval [CI], 2.2-2.6), female gender (OR, 1.9; 95% CI, 1.7-2.1), and large AAA diameter (OR, 1.7; 95% CI, 1.6-1.9). Patients with any in-hospital complication had lower unadjusted survival estimates than patients without complications at 1 year (83% vs 95%; P < .001), 5 years (66% vs 80%; P < .001), and 8 years (60% vs 72%; P < .001). After risk adjustment, in-hospital complications were independently associated with higher mortality, although the association attenuated over time (first month after discharge: hazard ratio [HR], 5.9; 95% CI, 3.9-9.1; 1-6 months after the procedure: HR, 2.1; 95% CI, 1.7-2.7; P < .001; 7-12 months after the procedure: HR, 1.5; 95% CI, 1.1-1.9; 1-8 years after the procedure: HR, 1.2; 95% CI, 1.01-1.3). Of all deaths occurring within 8 years after procedure, 9.5% were independently associated with in-hospital complications. Complications with the greatest impact on long-term mortality were renal dysfunction (2.4%), blood transfusion (3.4%), and reintubations (2.4%). CONCLUSIONS: Elderly patients are at higher risk for in-hospital complications after EVAR. These in-hospital complications have a significant impact on both short- and long-term survival. To further improve the delivery of EVAR care nationally, quality improvement efforts should be focused on preventing postoperative morbidity in elderly patients, as well as refining out of hospital surveillance strategies for subjects who experience in-hospital complications to improve overall survival.

Combined massive allograft and intramedullary vascularized fibula transfer: the Capanna technique for treatment of congenital pseudarthrosis of the tibia.

Background and purpose - Congenital pseudarthrosis of the tibia (CPT) is caused by local periosteal disease that can lead to bowing, fracturing, and pseudarthrosis. Current most successful treatment methods are segmental bone transport and vascularized and non-vascularized bone grafting. These methods are commonly hampered by discomfort, reoperations, and long-term complications. We report a combination of a vascularized fibula graft and large bone segment allograft, to improve patient comfort with similar outcomes.Patients and methods - 7 limbs that were operated on in 6 patients between November 2007 and July 2018 with resection of the CPT and reconstruction with a vascularized fibula graft in combination with a bone allograft were retrospectively studied. The mean follow-up time was 5.4 years (0.9-9.6). Postoperative endpoints: time to discharge, time to unrestricted weight bearing, complications within 30 days, consolidation, number of fractures, and secondary deformities.Results - The average time to unrestricted weight bearing with removable orthosis was 3.5 months (1.2-7.8). All proximal anastomoses consolidated within 10 months (2-10). 4 of the 7 grafts fractured at the distal anastomosis between 6 and 14 months postoperatively. After reoperation, consolidation of the distal anastomosis was seen after 2.8 months (2-4). 1 patient required a below-knee amputation.Interpretation - This case series showed favorable results of the treatment of CPT through a combination of a vascularized fibula graft and large bone segment allograft, avoiding the higher reintervention rate and discomfort with ring frame bone transport, and the prolonged non-weight bearing with vascularized fibula transfer without reinforcement with a massive large bone segment allograft.

Fenestrated endovascular aneurysm repair is associated with lower perioperative morbidity and mortality compared with open repair for complex abdominal aortic aneurysms.

OBJECTIVE: The Zenith Fenestrated Endovascular Graft (ZFEN; Cook Medical, Bloomington, Ind) has expanded the anatomic eligibility of endovascular aneurysm repair (EVAR) for complex abdominal aortic aneurysms (AAAs). Current data on ZFEN mainly consist of single-institution experiences and show conflicting results. Therefore, we compared perioperative outcomes after repair using ZFEN with open complex AAA repair and infrarenal EVAR in a nationwide multicenter registry. METHODS: We identified all patients undergoing elective AAA repair using ZFEN, open complex AAA repair, and standard infrarenal EVAR between 2012 and 2016 within the American College of Surgeons National Surgical Quality Improvement Program targeted vascular module. Open complex AAA repairs were defined as those with a juxtarenal or suprarenal proximal AAA extent in combination with an aortic cross-clamping position that was above at least one renal artery. The primary outcome was perioperative mortality, defined as death within 30 days or within the index hospitalization. Secondary outcomes included postoperative renal dysfunction (creatinine concentration increase of >2 mg/dL from preoperative value or new dialysis), occurrence of any complication, procedure times, blood transfusion rates, and length of stay. To account for baseline differences, we calculated propensity scores and employed inverse probability-weighted logistic regression. RESULTS: We identified 6825 AAA repairs-220 ZFENs, 181 open complex AAA repairs, and 6424 infrarenal EVARs. Univariate analysis of ZFEN compared with open complex AAA repair demonstrated lower rates of perioperative mortality (1.8% vs 8.8%; P = .001), postoperative renal dysfunction (1.4% vs 7.7%; P = .002), and overall complications (11% vs 33%; P < .001). In addition, fewer patients undergoing ZFEN received blood transfusions (22% vs 73%; P < .001), and median length of stay was shorter (2 vs 7 days; P < .001). After adjustment, open complex AAA repair was associated with higher odds of perioperative mortality (odds ratio [OR], 4.9; 95% confidence interval [CI], 1.4-18), postoperative renal dysfunction (OR, 13; 95% CI, 3.6-49), and overall complication rates (OR, 4.2; 95% CI, 2.3-7.5) compared with ZFEN. Compared with infrarenal EVAR, ZFEN presented comparable rates of perioperative mortality (1.8% vs 0.8%; P = .084), renal dysfunction (1.4% vs 0.7%; P = .19), and any complication (11% vs 7.7%; P = .09). Furthermore, after adjustment, there was no significant difference between the odds of perioperative mortality, postoperative renal dysfunction, or any complication between infrarenal EVAR and ZFEN. CONCLUSIONS: ZFEN is associated with lower perioperative morbidity and mortality compared with open complex AAA repair, and outcomes are comparable to those of infrarenal EVAR. Long-term durability of ZFEN compared with open complex AAA repair warrants future research.

Editor's Choice - Systematic Review and Meta-Analysis of the Outcome of Treatment for Type II Endoleak Following Endovascular Aneurysm Repair.

OBJECTIVES: The efficacy and need for secondary interventions for type II endoleaks following endovascular abdominal aortic aneurysm repair (EVAR) remain controversial. This systematic review aimed at investigating the clinical outcomes of different type II endoleak treatments in patients with a persistent type II endoleak after EVAR. DATA SOURCES: Embase, Medline via Ovid, Web of Science Core Collection, the Cochrane CENTRAL, and Google Scholar. REVIEW METHODS: This systematic review was performed in accordance with the PRISMA Statement. Outcomes of interest were technical and clinical success, change in sac diameter, complications, need for additional interventions, abdominal aortic aneurysm (AAA) rupture, and (AAA related) mortality. Meta-analyses were performed with random effects models. RESULTS: A total of 59 studies were included, with a cumulative cohort of 1073 patients with persistent type II endoleak. Peri-operative complications following treatment of type II endoleaks occurred in 3.8% of patients (95% CI 2.7-5.2%), and AAA related mortality was 1.8% (95% CI 1.1-2.7%). Overall technical success was 87.9% (95% CI 83.1-92.1%), while clinical success was 68.4% (95% CI 61.2-75.1%). Among studies detailing sac dynamics, decrease or stable sac, with or without resolution, was achieved in 78.4% (95% CI 70.2-85.6%). Changes in sac diameter following type II endoleak treatment were documented in 157 patients to at least 24 months. Within this group an actual decrease in sac diameter was reported in only 27 of 40 patients. CONCLUSION: There is little evidence supporting the efficacy of secondary intervention for type II endoleaks after EVAR. Although generally safe, the lack of evidence supporting the efficacy of type II endoleak treatment leads to difficulty in assessing its merits.

Comparison of Endovascular Stent Grafts for Abdominal Aortic Aneurysm Repair in Medicare Beneficiaries.

BACKGROUND: Increased renal complications have been suggested with suprarenal stent grafts, but long-term analyses have been limited. Therefore, the purpose of this study was to evaluate the effect of endograft choice on perioperative and long-term outcomes. METHODS: We compared Medicare beneficiaries undergoing endovascular abdominal aortic aneurysms repair from 2005 to 2008 with endografts with infrarenal fixation and a single docking limb (AneuRx, Excluder) to those with suprarenal fixation and 2 docking limbs (Zenith), or a unibody configuration (Powerlink). Propensity score weighting accounted for differences in patient characteristics among the different graft formations, and perioperative mortality, complications, and length of stay and 4-year rates of survival, rupture, and reintervention were compared. RESULTS: Forty-six thousand one hundred seventy-one Medicare beneficiaries were identified including 11,002 (24%) with suprarenal fixation, 32,909 (71%) with infrarenal fixation, and 2,260 (5%) with a unibody graft. After propensity score weighting, there were no significant differences in patients' baseline clinical and demographic characteristics. The suprarenal fixation patients had higher rates of perioperative mortality (1.7% vs. 1.3%, P < 0.01), renal failure (6.0% vs. 4.7%, P < 0.001), and mesenteric ischemia (0.7% vs. 0.4%, P < 0.01) and longer length of stay (3.4 days vs. 3.0 days, P < 0.001) compared with patients with infrarenal fixation. Unibody grafts had higher rates of renal failure (5.9% vs. 4.7%, P < 0.001), mesenteric ischemia (1.0% vs. 0.4%, P < 0.001), and conversion to open repair (0.7% vs. 0.1%, P < 0.001) compared to those with infrarenal fixation and single docking limbs. At 4 years, mortality remained slightly higher with suprarenal compared to infrarenal fixation (30% vs. 29%, P = 0.047), although these patients had fewer conversions to open repair (0.6% vs. 0.9%, P = 0.03) and aneurysm-related reinterventions (10% vs. 12%, P < 0.01). At 4 years, unibody grafts had more aneurysm-related interventions compared to infrarenal fixation grafts (15% vs. 12%, P < 0.01) but fewer conversions to open repair (0.4% vs. 0.9%, P = 0.02). Late rupture did not differ among the groups. CONCLUSIONS: Compared to infrarenal fixation devices, patients who underwent EVAR with suprarenal fixation had higher perioperative mortality and renal complications but fewer reinterventions including conversion, while the unibody graft had more perioperative complications and aneurysm-related reinterventions, but fewer conversions to open repair. Although these differences could be explained by selection bias, these data suggest that further comparative effectiveness analyses should be performed to understand the outcomes following EVAR with suprarenal fixation and unibody grafts.

Treatment of Craniosynostosis: The Impact of Hospital Surgical Volume on Cost, Resource Utilization, and Outcomes.

The authors aim to quantify the impact of hospital volume of craniosynostosis surgery on inpatient complications and resource utilization using national data. Children <12 months with nonsyndromic craniosynostosis who underwent surgery in 2012 at academic hospitals in the United States were identified from the Kids' Inpatient Database (KID) developed by the Healthcare Cost and Utilization Project (HCUP). Hospital craniosynostosis surgery volume was stratified into tertiles based on total annual hospital cases: low volume (LV, 1-13), intermediate volume (IV, 14-34), and high volume (HV, ≥35). Outcomes of interest include major complications, blood transfusion, charges, and length of stay (LOS). In 2012, 154 hospitals performed 1617 total craniosynostosis surgeries. Of these 580 cases (35.8%) were LV, 549 cases (33.9%) were IV, and 488 cases (30.2%) were HV. There was no difference in major complications between hospital volume tertiles (4.3% LV; 3.8% IV; 3.1% HV; P = 0.487). The highest blood transfusion rates were seen at LV hospitals (47.8% LV; 33.9% IV; 26.2%; P < 0.001). Hospital charges were lowest at HV hospitals ($55,839) compared with IV hospitals ($65,624; P < 0.001) and LV hospitals ($62,325; P = 0.005). Mean LOS was shortest at HV hospitals (2.96 days) compared with LV hospitals (3.31 days; P = 0.001); however, there was no difference when compared with IV hospitals (3.07 days; P = 0.282). Hospital case volume may be an important associative factor of blood transfusion rates, LOS, and hospital charges; however, there is no difference in complication rates. These results may be used to guide quality improvement within the surgical management of craniosynostosis.

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.

The impact of endovascular repair on management and outcome of ruptured thoracic aortic aneurysms.

BACKGROUND: Thoracic endovascular aortic repair (TEVAR) has become an alternative to open repair for the treatment of ruptured thoracic aortic aneurysms (rTAAs). The aim of this study was to assess national trends in the use of TEVAR for the treatment of rTAA and to determine its impact on perioperative outcomes. METHODS: Patients admitted with an rTAA between 1993 and 2012 were identified from the National Inpatient Sample. Patients were grouped in accordance with their treatment: TEVAR, open repair, or nonoperative treatment. The primary outcomes were treatment trends over time and in-hospital death. Secondary outcomes included perioperative complications and length of stay. Trend analyses were performed using the Cochran-Armitage test for trend, and adjusted mortality risks were established using multivariable logistic regression analysis. RESULTS: A total of 12,399 patients were included, with 1622 (13%) undergoing TEVAR, 2808 (23%) undergoing open repair, and 7969 (64%) not undergoing surgical treatment. TEVAR has been increasingly used from 2% of total admissions in 2003-2004 to 43% in 2011-2012 (P < .001). Concurrently, there was a decline in the proportion of patients undergoing open repair (29% to 12%; P < .001) and nonoperative treatment (69% to 45%; P < .001). The proportion of patients undergoing surgical repair has increased for all age groups since 1993-1994 (P < .001 for all) but was most pronounced among those aged 80 years with a 7.5-fold increase. After TEVAR was introduced, procedural mortality decreased from 36% in 2003-2004 to 27% in 2011-2012 (P < .001); mortality among those undergoing nonoperative treatment remained stable between 63% and 60% (P = .167). Overall mortality after rTAA admission decreased from 55% to 42% (P < .001). Since 2005, mortality for open repair was 33% and 22% for TEVAR (P < .001). In adjusted analysis, open repair was associated with a twofold higher mortality than TEVAR (odds ratio, 2.0; 95% confidence interval, 1.7-2.5). CONCLUSIONS: TEVAR has replaced open repair as primary surgical treatment for rTAA. The introduction of endovascular treatment appears to have broadened the eligibility of patients for surgical treatment, particularly among the elderly. Mortality after rTAA admission has declined since the introduction of TEVAR, which is the result of improved operative mortality as well as the increased proportion of patients undergoing surgical repair.

Perioperative outcomes of infrainguinal bypass surgery in patients with and without prior revascularization.

OBJECTIVE: Although an increasing number of patients with peripheral arterial disease undergo multiple revascularization procedures, the effect of prior interventions on outcomes remains unclear. The purpose of this study was to evaluate perioperative outcomes of bypass surgery in patients with and those without prior ipsilateral treatment. METHODS: Patients undergoing nonemergent infrainguinal bypass between 2011 and 2014 were identified in the National Surgical Quality Improvement Program Targeted Vascular module. After stratification by symptom status (chronic limb-threatening ischemia [CLTI] and claudication), patients undergoing primary bypass were compared with those undergoing secondary bypass. Within the secondary bypass group, further analysis compared prior bypass with prior endovascular intervention. Multivariable logistic regression analysis was used to establish the independent association between prior ipsilateral procedure and perioperative outcomes. RESULTS: A total of 7302 patients were identified, of which 4540 (62%) underwent primary bypass (68% for CLTI), 1536 (21%) underwent secondary bypass after a previous bypass (75% for CLTI), and 1226 (17%) underwent secondary bypass after a previous endovascular intervention (72% for CLTI). Prior revascularization on the same ipsilateral arteries was associated with increased 30-day major adverse limb event in patients with CLTI (9.8% vs 7.4%; odds ratio [OR], 1.4 [95% confidence interval (CI), 1.1-1.7]) and claudication (5.2% vs 2.5%; OR, 2.1 [95% CI, 1.3-3.5]). Similarly, secondary bypass was an independent risk factor for 30-day major reintervention (CLTI: OR, 1.4 [95% CI, 1.1-1.8]; claudication: OR, 2.1 [95% CI, 1.3-3.5]), bleeding (CLTI: OR, 1.4 [95% CI, 1.2-1.6]; claudication: OR, 1.7 [95% CI, 1.3-2.4]), and unplanned reoperation (CLTI: OR, 1.2 [95% CI, 1.0-1.4]; claudication: OR, 1.6 [95% CI, 1.1-2.1]), whereas major amputation was increased in CLTI patients only (OR, 1.3 [95% CI, 1.01-1.8]). Postoperative mortality was not significantly different in patients undergoing secondary compared with primary bypass (CLTI: 1.7% vs 2.2% [P = .22]; claudication: 0.4% vs 0.6% [P = .76]). Among secondary bypass patients with CLTI, those with prior bypass had higher 30-day reintervention rates (7.8% vs 4.9%; OR, 1.5 [95% CI, 1.0-2.2]) but fewer wound infections (7.3% vs 12%; OR, 0.6 [95% CI, 0.4-0.8]) compared with patients with prior endovascular intervention. CONCLUSIONS: Prior revascularization, in both patients with CLTI and patients with claudication, is associated with worse perioperative outcomes compared with primary bypass. Furthermore, prior endovascular intervention is associated with increased wound infections, whereas those with prior bypass had higher reintervention rates. The increasing prevalence of patients undergoing multiple interventions stresses the importance of the selection of patients for initial treatment and should be factored into subsequent revascularization options in an effort to decrease adverse events.

Risk factors for 30-day unplanned readmission following infrainguinal endovascular interventions.

OBJECTIVE: Unplanned hospital readmissions following surgical interventions are associated with adverse events and contribute to increasing health care costs. Despite numerous studies defining risk factors following lower extremity bypass surgery, evidence regarding readmission after endovascular interventions is limited. This study aimed to identify predictors of 30-day unplanned readmission following infrainguinal endovascular interventions. METHODS: We identified all patients undergoing an infrainguinal endovascular intervention in the targeted vascular module of the American College of Surgeons National Surgical Quality Improvement Program between 2012 and 2014. Perioperative outcomes were stratified by symptom status (chronic limb-threatening ischemia [CLI] vs claudication). Patients who died during index admission and those who remained in the hospital after 30 days were excluded. Indications for unplanned readmission related to the index procedure were evaluated. Multivariable logistic regression was used to identify preoperative and in-hospital (during index admission) risk factors of 30-day unplanned readmission. RESULTS: There were 4449 patients who underwent infrainguinal endovascular intervention, of whom 2802 (63%) had CLI (66% tissue loss) and 1647 (37%) had claudication. The unplanned readmission rates for CLI and claudication patients were 16% (n = 447) and 6.5% (n = 107), respectively. Mortality after index admission was higher for readmitted patients compared with those not readmitted (CLI, 3.4% vs 0.7% [P < .001]; claudication, 2.8% vs 0.1% [P < .01]). Approximately 50% of all unplanned readmissions were related to the index procedure. Among CLI patients, the most common indication for readmission related to the index procedure was wound or infection related (42%), whereas patients with claudication were mainly readmitted for recurrent symptoms of peripheral vascular disease (28%). In patients with CLI, predictors of unplanned readmission included diabetes (odds ratio, 1.3; 95% confidence interval, 1.01-1.6), congestive heart failure (1.6; 1.1-2.5), renal insufficiency (1.7; 1.3-2.2), preoperative dialysis (1.4; 1.02-1.9), tibial angioplasty/stenting (1.3; 1.04-1.6), in-hospital bleeding (1.9; 1.04-3.5), in-hospital unplanned return to the operating room (1.9; 1.1-3.5), and discharge other than to home (1.5; 1.1-2.0). Risk factors for those with claudication were dependent functional status (3.5; 1.4-8.7), smoking (1.6; 1.02-2.5), diabetes (1.5; 1.01-2.3), preoperative dialysis (3.6; 1.6-8.3), procedure time exceeding 120 minutes (1.8; 1.1-2.7), in-hospital bleeding (2.9; 1.2-7.4), and in-hospital unplanned return to the operating room (3.4; 1.2-9.4). CONCLUSIONS: Unplanned readmission after endovascular treatment is relatively common, especially in patients with CLI, and is associated with substantially increased mortality. Awareness of these risk factors will help providers identify patients at high risk who may benefit from early surveillance, and prophylactic measures focused on decreasing postoperative complications may reduce the rate of readmission.

Early extubation reduces respiratory complications and hospital length of stay following repair of abdominal aortic aneurysms.

BACKGROUND: Early extubation after cardiac surgery is associated with decreased hospital stay and resource savings with similar mortality and has led to the widespread use of early extubation protocols. In the Vascular Quality Initiative, there is significant regional variation in the frequency of extubation in the operating room (endovascular aneurysm repair [EVAR], 77%-97%; open repair, 30%-70%) after repair of intact abdominal aortic aneurysms (AAAs). However, the effects of extubation practices on patient outcomes after repair of AAAs are unclear. METHODS: All patients undergoing repair of an intact AAA in the Vascular Study Group of New England from 2003 to 2015 were evaluated. Patients undergoing concomitant procedures or conversions were excluded. Timing of extubation was stratified for EVAR (operating room, <12 hours, >12 hours) and open repair (operating room, <12 hours, 12-24 hours, >24 hours). Prolonged hospital stay was defined as >2 days after EVAR and >7 days after open repair. Univariate and multivariable analyses were completed, and independent predictors of extubation outside of the operating room were identified. RESULTS: There were 5774 patients evaluated (EVAR, 4453; open repair, 1321). After both EVAR and open repair, respiratory complications, prolonged hospital stay, and discharge to a skilled nursing facility (SNF) increased with intubation time. After adjustment, the odds of complications increased with each 12-hour delay in extubation: respiratory (EVAR: odds ratio [OR], 4.3 [95% confidence interval (CI), 3.0-6.1]; open repair: OR, 1.8 [95% CI, 1.5-2.2]), prolonged hospital stay (EVAR: OR, 2.7 [95% CI, 2.0-3.8]; open repair: OR, 1.3 [95% CI, 1.1-1.4]), and discharge to SNF (EVAR: OR, 2.0 [95% CI, 1.5-2.8]; open repair: OR, 1.4 [95% CI, 1.1-1.6]). Predictors of extubation outside of the operating room after EVAR included increasing age (OR, 1.5; 95% CI, 1.2-1.8), congestive heart failure (OR, 1.9; 95% CI, 1.2-3.0), chronic obstructive pulmonary disease (OR, 2.0; 95% CI, 1.4-2.9), symptomatic aneurysm (OR, 3.8; 95% CI, 2.3-5.7), and increasing diameter (OR, 1.01; 95% CI, 1.01-1.01). After open repair, increasing age (OR, 1.4; 95% CI, 1.1-1.6), congestive heart failure (OR, 1.8; 95% CI, 1.01-3.3), dialysis (OR, 2.8; 95% CI, 1.7-70), symptomatic aneurysm (OR, 2.8; 95% CI, 1.9-4.3), and hospital practice patterns (OR, 1.01; 95% CI, 1.01-1.01) were predictive of extubation outside of the operating room. CONCLUSIONS: The benefits of early extubation in cardiac patients are also seen after AAA repair. Suitable patients should be extubated in the operating room to decrease respiratory complications, length of stay, and discharge to an SNF. Early extubation protocols should be considered to reduce regional variation in extubation practices and to improve patient outcomes.

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.

Clinical presentation, management, follow-up, and outcomes of isolated celiac and superior mesenteric artery dissections.

OBJECTIVE: Isolated visceral artery dissections are rare entities with no current consensus guidelines for treatment and follow-up. This study aims to evaluate the presentation, management, outcomes, and follow-up practices for patients with isolated visceral artery dissections and to compare those with and without symptoms. METHODS: In this retrospective analysis, we identified all patients with isolated celiac artery and/or isolated superior mesenteric artery dissections at a single institution between September 2006 and December 2014. Patients with concomitant aortic dissections were excluded. Cases were stratified by symptom status. Presentation, anatomic findings, treatment, outcomes, and follow-up imaging were then compared between symptomatic and asymptomatic patients. RESULTS: We identified 25 patients including 15 with symptoms and 10 without. There were no differences in patient comorbidities; however, symptomatic patients more frequently presented with thrombus (n = 10; 67% vs n = 1; 10%; P = .01) and inflammation (n = 8; 53% vs n = 1; 10%; P = .04), and trended toward increased stenosis (n = 12; 80% vs n = 4; 40%; P = .09) compared with asymptomatic patients. All asymptomatic patients were treated with observation alone with vessel diameter enlargement noted in 33% (n = 2) of patients on follow-up imaging. Among symptomatic patients, standard treatment included a short course of anticoagulation (mean, 4.5 months) with lifelong antiplatelet therapy. Three patients underwent operative intervention for persistent or worsening symptoms, two during the index admission and one 10 months after presentation for chronic abdominal pain. Approximately 70% (n = 17) of patients in each group had follow-up imaging (computed tomography angiography: n = 14; 56%; magnetic resonance angiography: n = 4; 16%; ultrasound: n = 13; 52%). Among patients treated nonoperatively, no patients complained of symptoms at follow-up, and 50% of those with inflammation on initial imaging had resolution. Twenty-five percent (n = 4) of patients had an increase in vessel size; however, all vessels remained less than 2 cm in maximal diameter. There were no ruptures or related deaths in either group. CONCLUSIONS: Among patients with visceral artery dissection, no ruptures occurred but diameter enlargement was documented. This disease progression suggests that routine surveillance may be appropriate; however, transitioning early to ultrasound imaging should be considered to decrease radiation, contrast, and associated costs.

Elevated serum phosphate levels are associated with decreased amputation-free survival after interventions for critical limb ischemia.

OBJECTIVE: Elevated serum phosphate levels have been associated with increased risks of cardiovascular events and death in several patient populations. The effects of serum phosphate on outcomes in patients with critical limb ischemia (CLI) have not been evaluated. In this study, we assessed the effect of abnormal phosphate levels on mortality and major limb events after surgical intervention for CLI. METHODS: A retrospective review was undertaken to identify all patients at a single institution who underwent a first-time open or endovascular intervention for CLI between 2005 and 2014. Patients without recorded postoperative phosphate levels were excluded. Postoperative phosphate levels ≤30 days of the initial operation were recorded, and the mean was calculated. Patients were stratified according to mean phosphate levels (low: <2.5 mg/dL, normal: 2.5-4.5 mg/dL, and high: >4.5 mg/dL). Patient demographics, comorbidities, and operative details were compared in univariate analysis. Multivariable regression and Cox proportional hazard modeling were used to account for patient demographics and comorbid conditions. RESULTS: We identified 941 patients, including 42 (5%) with low phosphate, 768 (82%) with normal phosphate, and 131 (14%) with high phosphate. Patients with elevated phosphate were younger and had higher rates of congestive heart failure, diabetes, and dialysis dependence. Bypass was more common among patients with normal phosphate compared with high or low phosphate levels. There was no difference in the Wound, ischemia, and Foot infection (WiFi) classification or TransAtlantic Inter-Society Consensus classification among the cohorts. There were significant differences in 1-year mortality (low: 19%, normal: 17%, high: 33%; P < .01) and 3-year mortality (low: 38%, normal: 34%, high: 56%; P < .01) between phosphate cohorts. Major amputation (low: 12%, normal: 12%, high: 15%) and restenosis (low: 21%, normal: 24%, high: 28%) tended toward worse outcomes among patients with elevated phosphate levels but did not reach statistical significance. After adjustment for baseline characteristics, mortality was higher (hazard ratio [HR], 1.7; 95% confidence interval [CI], 1.3-2.2) and amputation-free survival was lower (HR, 1.5; 95% CI, 1.2-1.9) among patients with elevated compared with normal phosphate levels. A subgroup analysis was then performed to assess dialysis and nondialysis patients separately. Patients with elevated serum phosphate levels maintained a significantly higher risk of mortality in each group (dialysis: HR, 1.8; 95% CI, 1.2-2.6; nondialysis: HR, 1.5; 95% CI, 1.04-2.10). CONCLUSIONS: Elevated phosphate levels are associated with increased mortality and decreased amputation-free survival after interventions for CLI. Future studies evaluating the effects of phosphate reduction in patients with CLI are warranted.

Predictors of renal dysfunction after endovascular and open repair of abdominal aortic aneurysms.

OBJECTIVE: Renal complications after repair of abdominal aortic aneurysms (AAAs) have been associated with increased morbidity and mortality. However, limited data have assessed risk factors for renal complications in the endovascular era. This study aimed to identify predictors of renal complications after endovascular AAA repair (EVAR) and open repair. METHODS: Patients who underwent EVAR or open repair of a nonruptured infrarenal AAA between 2011 and 2013 were identified in the National Surgical Quality Improvement Project Targeted Vascular module. Patients on hemodialysis preoperatively were excluded. Renal complications were defined as new postoperative dialysis or creatinine increase >2 mg/dL. Patient demographics, comorbidities, glomerular filtration rate (GFR), operative details, and outcomes were compared using univariate analysis between those with and without renal complications. Multivariable logistic regression was used to identify independent predictors of renal complications. RESULTS: We identified 4503 patients who underwent elective repair of an infrarenal AAA (EVAR: 3869, open repair: 634). Renal complication occurred in 1% of patients after EVAR and in 5% of patients after open repair. There were no differences in comorbidities between patients with and without renal complications. A preoperative GFR <60 mL/min/1.73m2 occurred more frequently among patients with renal complications (EVAR: 81% vs 37%, P < .01; open: 60% vs 34%, P < .01). The 30-day mortality was also significantly increased (EVAR: 55% vs 1%, P < .01; open: 30% vs 4%, P < .01). After adjustment, renal complications were strongly associated with 30-day mortality (odds ratio [OR], 38.3; 95% confidence interval [CI], 20.4-71.9). Independent predictors of renal complications included GFR <60 mL/min/1.73m2 (OR, 4.6; 95% CI, 2.4-8.7), open repair (OR, 2.6; 95% CI, 1.3-5.3), transfusion (OR, 6.1; 95% CI, 3.0-12.6), and prolonged operative time (OR, 3.0; 95% CI, 1.6-5.6). CONCLUSIONS: Predictors of renal complications include elevated baseline GFR, open approach, transfusion, and prolonged operative time. Given the dramatic increase in mortality associated with renal complications, care should be taken to use renal protective strategies, achieve meticulous hemostasis to limit transfusions, and to use an endovascular approach when technically feasible.

Trends in Treatment and Mortality for Mesenteric Ischemia in the United States from 2000 to 2012.

BACKGROUND: It is unknown whether increased endovascular treatment of chronic mesenteric ischemia has led to decreases in open surgery, acute mesenteric ischemia, or overall mortality. The present study evaluates the trends in endovascular and open treatment over time for chronic and acute mesenteric ischemia. METHODS: We identified patients with chronic or acute mesenteric ischemia in the Nationwide Inpatient Sample and Center for Disease Control and Prevention database from 2000 to 2012. Trends in revascularization, mortality, and total deaths were evaluated over time. Data were adjusted to account for population growth. RESULTS: There were 14,810 revascularizations for chronic mesenteric ischemia (10,453 endovascular and 4,358 open) and 11,294 revascularizations for acute mesenteric ischemia (4,983 endovascular and 6,311 open). Endovascular treatment increased for both chronic (0.6-4.5/million, P < 0.01) and acute mesenteric ischemia (0.6-1.8/million, P < 0.01). However, concurrent declines in open surgery did not occur (chronic: 1-1.1/million, acute: 1.8-1.7/million). Among patients with acute mesenteric ischemia, the proportion with atrial fibrillation (18%) and frequency of embolectomy (1/million per year) remained stable. In-hospital mortality rates decreased for both endovascular (chronic: 8-3%, P < 0.01; acute: 28-17%, P < 0.01) and open treatment (chronic: 21-9%, P < 0.01; acute: 40-25%, P < 0.01). Annual population-based mortality remained stable for chronic mesenteric ischemia (0.7-0.6 deaths per million/year), but decreased for acute mesenteric ischemia (12.9-5.3 deaths per million/year, P < 0.01). CONCLUSIONS: Population mortality from acute mesenteric ischemia declined from 2000 to 2012, correlated with dramatic increases in endovascular intervention for chronic mesenteric ischemia, and in spite of a stable rate of embolization. However, open surgery for both chronic and acute ischemia remained stable.

Conversion from endovascular to open abdominal aortic aneurysm repair.

BACKGROUND: Previous studies have found conflicting results regarding the operative risks associated with conversion to open abdominal aortic aneurysm (AAA) repair after failed endovascular treatment (endovascular aneurysm repair [EVAR]). The purpose of this study was to assess the outcome of patients undergoing a conversion, and compare outcomes with standard open AAA repair and EVAR. In addition, we sought out to identify factors associated with conversion. METHODS: All patients undergoing a conversion to open repair, and those undergoing standard EVAR and open repair between 2005 and 2013 were included from the National Surgical Quality Improvement Program. Multivariable logistic regression analysis was used to identify factors associated with conversion, and to assess independent perioperative risks associated with conversion compared with standard AAA repair. Subanalysis for factors associated with conversion was performed among patients additionally included in the more detailed targeted vascular module of the National Surgical Quality Improvement Program. RESULTS: A total of 32,164 patients were included, with 300 conversions, 7188 standard open repairs, and 24,676 EVARs. Conversion to open repair was associated with a significantly higher 30-day mortality than standard open repair (10.0% vs 4.2%; odds ratio [OR], 2.4; 95% confidence interval [CI], 1.6-3.6; P < .001), and EVAR (10.0% vs 1.7%; OR, 7.2; 95% CI, 4.8-10.9; P < .001). Conversion surgery was additionally followed by an increased occurrence of any complication (OR, 1.5; 95% CI, 1.2-1.9 [open]; OR, 7.8; 95% CI, 6.1-9.9 [EVAR]). Factors associated with conversion were young age (OR, 1.2 per 10 years decrease; 95% CI, 1.1-1.4), female gender (OR, 1.5; 95% CI, 1.2-2.0), and nonwhite race (OR, 1.8; 95% CI, 1.3-2.6). Conversely, body mass index >30 was negatively associated with (OR, 0.7; 95% CI, 0.5-0.9). Among anatomic characteristics captured in the targeted vascular data set (n = 4555), large aneurysm diameter demonstrated to be strongly associated with conversion (OR, 1.1 per 1 cm increase; 95% CI, 1.03-1.1). CONCLUSIONS: Conversion to open repair after failed EVAR is associated with substantially increased perioperative morbidity and mortality compared with standard AAA repair. Factors associated with conversion are large diameter of the aneurysm, young age, female gender, and nonwhite race, whereas obesity is inversely related to conversion surgery.

Life expectancy and causes of death after repair of intact and ruptured abdominal aortic aneurysms.

BACKGROUND: Life expectancy and causes of death after abdominal aortic aneurysm (AAA) repair are not well characterized. Population aging and improved secondary prevention may have modified the prognosis of these patients. We designed a retrospective cohort study to determine the vital prognosis, causes of death, and differences in outcome after intact and ruptured AAA. METHODS: All patients with AAA treated from 2003 to 2011 at a single university institution in The Netherlands were analyzed. Survival status was derived from civil registry data. Causes of death were obtained from death certificates. The primary end point was overall mortality. Secondary end points were cardiovascular, cancer-related, and AAA-related mortality. Predictors for perioperative and late survival were obtained by logistic regression and Cox regression models, respectively. RESULTS: The study included 619 consecutive AAA patients (12% women; mean age, 72 years), of whom 152 (24.5%) had ruptured AAAs. Endovascular repair was performed in 390 (63%). Rupture (odds ratio [OR], 10.63; 95% confidence interval [CI], 4.80-23.5), open repair (OR, 3.59; 95% CI, 1.69-7.62), renal insufficiency (OR, 2.94; 95% CI, 1.51-3.46), and age (OR, 1.08 per year; 95% CI, 1.09-1.15) were predictors of 30-day mortality. Five-year survival expectancy was 65% for intact AAA and 41% for ruptured AAA (P < .001). Cardiovascular deaths unrelated to the AAA occurred in 35% and cancer-related deaths in 29% of deceased patients. Predictors for late mortality were history of prior malignant disease (hazard ratio, 2.83; 95% CI, 1.99-4.03) and age (hazard ratio, 1.08 per year; 95% CI, 1.05-1.10). After 30 days, only six deaths (1.1%) were AAA related. CONCLUSIONS: Endovascular repair reduced perioperative mortality by threefold, but no survival benefit was observed at long term. After the perioperative period, survival of ruptured AAA and intact AAA patients was not different. Deaths were distributed in similar proportions between cardiovascular and cancer-related causes.