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.

Long Term Outcomes of Post-Implantation Syndrome After Endovascular Aneurysm Repair.

OBJECTIVE: The aim of this study was to investigate the association between post-implantation syndrome (PIS) and long term outcomes, with emphasis on cardiovascular prognosis. METHODS: One hundred and forty-nine consecutive patients undergoing EVAR in a tertiary institution were previously included in a study investigating the risk factors and short term consequences of PIS (defined as tympanic temperature ≥ 38°C and CRP > 10 mg/L, after excluding complications with an effect on inflammatory markers). This study was based on a prospectively maintained database. Survival status was derived from inquiry of civil registry database information and causes of death from the Dutch Central Bureau of Statistics. The primary endpoint was cardiovascular events. Secondary endpoints were overall and specific cause mortality (cardiovascular, ischaemic heart disease, AAA, and cancer related mortality). Aneurysm sac dynamics and occurrence of endoleaks were also analysed. Survival estimates were obtained using Kaplan-Meier plots and a multivariable model was constructed to correct for confounders. RESULTS: The PIS incidence was 39% (58/149). At the time of surgery, patients had a mean age of 73 ± 7 years and were predominantly male. There were no baseline differences between the PIS and non-PIS groups. The median follow up was 6.4 years (3.2 - 8.3), similar in both groups (p = .81). There was no difference in cardiovascular events for PIS and non-PIS patients (p = .63). However, Kaplan-Meier plots suggest a trend towards a higher rate of cardiovascular events in PIS patients during the first years: freedom from cardiovascular events at one year was 94% vs. 89% and at three years 90% vs. 82%. No differences were found in overall and specific cause mortality. There was a higher rate of type II endoleaks for non-PIS patients (28% vs. 9%, p = .005). Sac dynamics were similar in both groups. CONCLUSION: The results suggest that PIS is not associated with a statistically significantly higher risk of cardiovascular events. PIS had no impact on mortality. Lastly, PIS patients had fewer type II endoleaks, but sac dynamics were analogous.

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.

Survival After Uncomplicated EVAR in Octogenarians is Similar to the General Population of Octogenarians Without an Abdominal Aortic Aneurysm.

OBJECTIVE: Long term survival after endovascular aortic aneurysm repair (EVAR) in octogenarians remains unclear. This was evaluated by comparing octogenarians after EVAR with a matched group of octogenarians without an abdominal aortic aneurysm (AAA) from the Rotterdam Study (RS). The influence of complications after EVAR on survival was also studied with the aim of identifying risk factors for the development of complications in octogenarians. METHODS: Using propensity score matching (PSM), 83 EVAR octogenarians were matched for comorbidities with 83 octogenarians from the RS, and survival was compared between these two groups using Cox proportional hazard analysis. Then, complications were studied, defined as cardiac or pulmonary, renal deterioration, access site bleeding, acute limb ischaemia or bowel ischaemia, within 30 days of surgery between 83 EVAR octogenarians and 475 EVAR non-octogenarians. Also, the difference in baseline characteristics between the octogenarians with and without complications after EVAR were studied, and survival was compared between the RS controls and the complicated and uncomplicated EVAR octogenarians separately. RESULTS: The total EVAR octogenarian population did not show an increased mortality risk compared with RS octogenarian controls (hazard ratio [HR] 1.28, 95% confidence interval [CI] 0.84-1.97). Post-operative complications occurred in 22 octogenarians (27%) and 59 non-octogenarians (12.4%, p < .001), mainly cardiac, pulmonary, and bleeding complications. All baseline characteristics were similar in the complicated EVAR octogenarians compared with the uncomplicated EVAR octogenarians. After uncomplicated EVAR, octogenarians had a similar survival compared with the RS controls (HR 1.09, 95% CI 0.68-1.77), but after complicated EVAR their mortality risk increased significantly (HR 1.93, 95% CI 1.06-3.54). CONCLUSION: After standard EVAR, the life expectancy of octogenarians is the same as that of a matched group from the general population without an AAA, provided they do not develop early post-operative complications. Patient selection and meticulous peri-operative care are key.

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.

Anatomic predictors for late mortality after standard endovascular aneurysm repair.

OBJECTIVE: Abdominal aortic aneurysm (AAA) management involves a decision process that takes into account anatomic characteristics, surgical risks, patients' preferences, and expected survival. Whereas larger AAA diameter has been associated with increased mortality after both standard endovascular aneurysm repair (EVAR) and open repair, it is unclear whether survival after EVAR is influenced by other anatomic characteristics. The purpose of this study was to determine the importance of baseline anatomic features on survival after EVAR. METHODS: All patients treated at a tertiary teaching center with EVAR for intact standard infrarenal AAA from 2000 to 2014 were included. The civil data registry was queried to determine survival status; causes of death were obtained from death certificates. The primary study end point was to determine the impact of baseline morphologic features on all-cause and cardiovascular mortality after EVAR. RESULTS: This study included 404 EVAR patients (12.1% women; mean age, 73 years) with a median follow-up of 5.8 years (interquartile range, 3.1-7.4 years). The 5- and 10-year overall survival rates for the entire population after EVAR were 70% (95% confidence interval [CI], 66%-75%) and 43% (95% CI, 37%-50%), respectively. Only AAA diameter >70 mm (hazard ratio [HR], 1.75; 95% CI, 1.20-3.56) was identified as an independent anatomic predictor of all-cause mortality. Death due to cardiovascular causes occurred in 60 (38.5%) patients. Aneurysm-related mortality was responsible for six of the cardiovascular-related deaths. In multivariable analysis, both neck diameter ≥30 mm (HR, 2.16; 95% CI, 1.05-4.43) and AAA diameter >70 mm (HR, 2.45; 95% CI, 1.34-4.46) were identified as independent morphologic risk factors for cardiovascular mortality, whereas >25% circumferential neck thrombus (HR, 0.32; 95% CI, 0.13-0.77) was protective. CONCLUSIONS: This study suggests that patients with AAA diameters >70 mm are at increased risk of all-cause and cardiovascular mortality. In addition, patients with infrarenal neck diameters ≥30 mm have a greater risk of cardiovascular mortality, although AAA-related deaths were not more frequent in this group of patients. Consequently, a more aggressive management of cardiovascular medical comorbidities may be warranted to improve survival after standard EVAR in these patients.

Patients with large neck diameter have a higher risk of type IA endoleaks and aneurysm rupture after standard endovascular aneurysm repair.

OBJECTIVE: Standard endovascular aneurysm repair (EVAR) is the most common treatment of abdominal aortic aneurysms (AAAs). EVAR has been increasingly used in patients with hostile neck features. This study investigated the outcomes of EVAR in patients with neck diameters ≥30 mm in the prospectively maintained Endurant Stent Graft Natural Selection Global Postmarket Registry (ENGAGE). METHODS: This is a retrospective study comparing patients with neck diameters ≥30 mm with patients with neck diameters <30 mm. The primary end point was type IA endoleak (EL1A). Secondary end points included secondary interventions to correct EL1A, aneurysm rupture, and survival. RESULTS: This study included 1257 patients (mean age, 73.1 years; 89.4% male) observed for a median 4.0 years (interquartile range, 2.7-4.8 years). A total of 97 (7.7%) patients had infrarenal neck diameters ≥30 mm and were compared with the remaining 1160 (92.3%) with neck diameters <30 mm. At baseline, there were no differences between groups regarding demographics and comorbidities other than cardiac disease, which was more frequent in the ≥30-mm neck diameter group (P = .037). There were no significant differences between the groups regarding neck length, angulation, thrombus, or calcification. Mean preoperative AAA diameter was 64.6 ± 11.3 mm in the ≥30-mm neck diameter group and 60.0 ± 11.6 mm in the <30-mm neck diameter group (P < .001). Stent graft oversizing was significantly less in the ≥30-mm neck diameter group (12.2% ± 8.9% vs 22.1% ± 11.9%; P <. 001). Five patients (5.2%) in the ≥30-mm neck diameter group and 30 (2.6%) with neck diameters <30 mm developed EL1A, yielding a 4-year freedom from EL1A of 92.4% vs 96.6%, respectively (P = .09). Oversizing was 21.8% ± 13.0% for patients developing EL1A and 21.3% ± 12.4% for the remaining cohort (P = .99). In adjusting for neck length, AAA diameter, and device oversizing, patients with neck diameter ≥30 mm were at greater risk for development of EL1A (hazard ratio, 3.0; 95% confidence interval, 1.0-9.3; P = .05). Secondary interventions due to EL1A did not differ between groups (P = .36). AAA rupture occurred in three patients with neck diameter ≥30 mm (3.1%) and in eight patients with neck diameter <30 mm (0.7%; hazard ratio, 5.1; 95% confidence interval, 1.4-19.2; P = .016); two cases were EL1A related in each group. At 4 years, overall survival was 61.6% for the ≥30-mm neck diameter group and 75.2% for the <30-mm neck diameter group (P = .009), which remained significant on correcting for sex and AAA diameter (P = .016). CONCLUSIONS: In this study, patients with infrarenal neck diameter ≥30 mm had a threefold increased risk of EL1A and fivefold risk of aneurysm rupture after EVAR as well as worse overall survival. This may influence the choice of AAA repair and underlines the need for regular computed tomography-based imaging surveillance in this subset of patients. Furthermore, these results can serve as standards with which new, possibly improved technology, such as EndoAnchors (Medtronic, Santa Rosa, Calif), can be compared.

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.

Long-term outcomes of standard endovascular aneurysm repair in patients with severe neck angulation.

OBJECTIVE: Severe neck angulation is associated with complications after endovascular aneurysm repair (EVAR). Newer endografts may overcome this limitation, but the literature lacks long-term results. We studied the long-term outcomes of EVAR in patients with severe neck angulation. METHODS: A retrospective case-control study of a prospective multicenter database was performed. All measurements were made with dedicated software with center lumen line reconstruction. A study group including patients with neck length >15 mm, infrarenal angle (ß) >75 degrees or suprarenal angle (α) >60 degrees, and neck length 10 to 15 mm with ß >60 degrees or α >45 degrees was compared with a control group matched for demographics and other morphologic neck features. The primary end point was type IA endoleak (EL1A). Secondary end points were freedom from neck-related secondary interventions, primary clinical success, and overall survival. RESULTS: Forty-five patients were included in the angulated neck group and compared with 65 matched patients. Median follow-up was 7.4 years (interquartile range, 4.8-8.5 years). In the angulated neck group, mean α was 51.4 degrees (±21.1 degrees) and the mean ß was 80.8 degrees (±15.6 degrees); in the nonangulated group, these were 17.9 degrees (±17.0 degrees) and 35.4 degrees (±20.0 degrees), respectively. At 7 years, five patients in the angulated neck group and two nonangulated patients developed EL1A, yielding a freedom from EL1A of 86.1% (n = 14; standard error [SE], 0.069) and 96.6% (n = 34; SE, 0.023), respectively (P = .056). After exclusion of a patient who developed an EL1A secondary to an endograft infection, this difference was significant: 86.1% (n = 14; SE, 0.069) in the angulated neck group and 98.2% (n = 34; SE, 0.018) in the nonangulated group (P = .016). At 7 years, freedom from neck-related secondary interventions was 91.7% (n = 14; SE, 0.059) and 91.6% (n = 29; SE, 0.029), respectively. The 7-year primary clinical success estimates were 41.2% (n = 11; SE, 0.085) and 56.6% (n = 20; SE, 0.072) for the angulated neck and nonangulated groups, respectively (P = .12). The 7-year survival rates were 44.3% (n = 18; SE, 0.076) vs 66.7% (n = 42; SE, 0.059) for the angulated neck and nonangulated groups, respectively (P = .25). Device integrity failure was not observed. CONCLUSIONS: Despite satisfactory results early and in the midterm, a higher rate of EL1A was identified among patients with severely angulated necks in the long term. However, mortality was not affected by this difference. These findings suggest that EVAR should be used judiciously in patients with extreme angulation of the proximal neck and highlight the need for close follow-up of EVAR, especially in the long term and in patients treated outside instructions for use.

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.

The Impact of Surgical Volume on Outcomes and Cost in Cleft Repair: A Kids' Inpatient Database Analysis.

BACKGROUND: Centralization of specialist services, including cleft service delivery, is occurring worldwide with the aim of improving the outcomes. This study examines the relationship between hospital surgical volume in cleft palate repair and outcomes. METHODS: A retrospective analysis of the Kids' Inpatient Database was undertaken. Children 3 years or younger undergoing cleft palate repair in 2012 were identified. Hospital volume was categorized by cases per year as low volume (LV; 0-14), intermediate volume (IV; 15-46), or high volume (HV; 47-99); differences in complications, hospital costs, and length of stay (LOS) were determined by hospital volume. RESULTS: Data for 2389 children were retrieved: 24.9% (n = 595) were LV, 50.1% (n = 1196) were IV, and 25.0% (n = 596) were HV. High-volume centers were more frequently located in the West (71.9%) compared with LV (19.9%) or IV (24.5%) centers (P < 0.001 for hospital region). Median household income was more commonly highest quartile in HV centers compared with IV or LV centers (32.3% vs 21.7% vs 18.1%, P < 0.001). There was no difference in complications between different volume centers (P = 0.74). Compared with HV centers, there was a significant decrease in mean costs for LV centers ($9682 vs $,378, P < 0.001) but no significant difference in cost for IV centers ($9260 vs $9682, P = 0.103). Both IV and LV centers had a significantly greater LOS when compared with HV centers (1.97 vs 2.10 vs 1.74, P < 0.001). CONCLUSIONS: Despite improvement in LOS in HV centers, we did not find a reduction in cost in HV centers. Further research is needed with analysis of outpatient, long-term outcomes to ensure widespread cost-efficiency.

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.

Drivers of Hospital Costs in the Self-Pay Facelift (Rhytidectomy) Patient: Analysis of Hospital Resource Utilization in 1890 Patients.

INTRODUCTION: Rhytidectomy is one of the most commonly performed cosmetic procedures by plastic surgeons. Increasing attention to the development of a high-value, low-cost healthcare system is a priority in the USA. This study aims to analyze specific patient and hospital factors affecting the cost of this procedure. METHODS: We conducted a retrospective cohort study of self-pay patients over the age of 18 who underwent rhytidectomy using the Healthcare Utilization Cost Project National Inpatient Sample database between 2013 and 2014. Mean marginal cost increases patient characteristics, and outcomes were studied. Generalized linear modeling with gamma regression and a log-link function were performed along with estimated marginal means to provide cost estimates. RESULTS: A total of 1890 self-pay patients underwent rhytidectomy. Median cost was $11,767 with an interquartile range of $8907 [$6976-$15,883]. The largest marginal cost increases were associated with postoperative hematoma ($12,651; CI $8181-$17,120), West coast region ($7539; 95% CI $6412-$8666), and combined rhinoplasty ($7824; 95% CI $3808-$11,840). The two risk factors associated with the generation of highest marginal inpatient costs were smoking ($4147; 95% CI $2804-$5490) and diabetes mellitus ($5622; 95% CI $3233-8011). High-volume hospitals had a decreased cost of - $1331 (95% CI - $2032 to - $631). CONCLUSION: Cost variation for inpatient rhytidectomy procedures is dependent on preoperative risk factors (diabetes and smoking), postoperative complications (hematoma), and regional trends (West region). Rhytidectomy surgery is highly centralized and increasing hospital volume significantly decreases costs. Clinicians and hospitals can use this information to discuss the drivers of cost in patients undergoing rhytidectomy. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The financial impact and drivers of hospital charges in contralateral prophylactic mastectomy and reconstruction: a Nationwide Inpatient Sample hospital analysis.

PURPOSE: Rates of contralateral prophylactic mastectomy (CPM) have increased over the last decade; it is important for surgeons and hospital systems to understand the economic drivers of increased costs in these patients. This study aims to identify factors affecting charges in those undergoing CPM and reconstruction. METHODS: Analysis of the Healthcare Cost and Utilization Project National Inpatient Sample was undertaken (2009-2012), identifying women aged ≥18 with unilateral breast cancer undergoing unilateral mastectomy with CPM and immediate breast reconstruction (IBR) (CPM group), in addition to unilateral mastectomy and IBR alone (UM group). Generalized linear modeling with gamma regression and a log-link function provided mean marginal hospital charge (MMHC) estimates associated with the presence or absence of patient, hospital and operative characteristics, postoperative complications, and length of stay (LOS). RESULTS: Overall, 70,695 women underwent mastectomy and reconstruction for unilateral breast cancer; 36,691 (51.9%) in the CPM group, incurring additional MMHCs of $20,775 compared to those in the UM group (p < 0.001). In the CPM group, MMHCs were reduced in those aged >60 years (p < 0.001), while African American or Hispanic origin increased MMHCs (p < 0.001). Diabetes, depression, and obesity increased MMHCs (p < 0.001). MMHCs increased with larger (p < 0.001) hospitals, Western location (p < 0.001), greater household income (p < 0.001), complications (p < 0.001), and increasing LOS (p < 0.001). MMHCs decreased in urban teaching hospitals and Midwest or Southern regions (p < 0.001). CONCLUSION: There are many patient and hospital factors affecting charges; this study provides surgeons and hospital systems with transparent, quantitative charge data in patients undergoing contralateral prophylactic mastectomy and immediate breast reconstruction.

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.

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.

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.

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.