Sara L. Zettervall

Sex differences in mortality and morbidity following repair of intact abdominal aortic aneurysms

Objective: Medicare studies have shown increased perioperative mortality in women compared with men following endovascular and open abdominal aortic aneurysm (AAA) repair. However, a recent regional study of high‐volume centers, adjusting for anatomy but limited in sample size, did not show sex to be predictive of worse outcomes. This study aimed to evaluate sex differences after intact AAA repair in a national clinical registry. Methods: The targeted vascular module of the National Surgical Quality Improvement Program was queried to identify patients undergoing endovascular aneurysm repair (EVAR) or open repair for intact, infrarenal AAA from 2011 to 2014. Univariate analysis was performed using the Fisher exact test and Mann‐Whitney test. Multivariable logistic regression was used to account for differences in comorbidities, aneurysm details, and operative characteristics. Results: We identified 6661 patients (19% women) who underwent intact AAA repair (87% EVAR; 83% women vs 88% men; P < .001). Women were older (median age, 76 vs 73 years; P < .001), had smaller aneurysms (median, 5.4 vs 5.5 cm; P < .001), and had more chronic obstructive pulmonary disease (22% vs 17%; P < .001). Among patients undergoing EVAR, women had longer operative times (median, 138 [interquartile range, 103–170] vs 131 [106–181] minutes; P < .01) and more often underwent renal (6.3% vs 4.1%; P < .01) and lower extremity (6.6% vs 3.8%; P < .01) revascularization. After open repair, women had shorter operative time (215 [177–304] vs 226 [165–264] minutes; P = .02), but women less frequently underwent lower extremity revascularization (3.1% vs 8.2%; P = .03). Thirty‐day mortality was higher in women after EVAR (3.2% vs 1.2%; P < .001) and open repair (8.0% vs 4.0%; P = .04). After adjusting for repair type, age, aneurysm diameter, and comorbidities, female sex was independently associated with mortality (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.1–2.6; P = .02) and major complications (OR, 1.4; CI, 1.1–1.7; P < .01) after intact AAA repair. However, after adjusting for aortic size index rather than for aortic diameter, the association between female sex and mortality (OR, 1.5; CI, 0.98–2.4; P = .06) and major complications (OR, 1.1; CI, 0.9–1.4; P = .24) was reduced. Conclusions: Women were at higher risk for 30‐day death and major complications after intact AAA repair. Some of this disparity may be explained by differences in aortic size index, which should be further evaluated to determine the ideal threshold for repair.

The effect of surgeon and hospital volume on mortality after open and endovascular repair of abdominal aortic aneurysms

Background: Higher hospital and surgeon volumes are independently associated with improved mortality after open repair of abdominal aortic aneurysms (AAAs) in the era before endovascular AAA repair (EVAR). The effects of both surgeon and hospital volume on mortality after EVAR and open repair in the current era are less well defined. Methods: We studied Medicare beneficiaries who underwent elective AAA repair from 2001 to 2008. Volume was measured by procedure type during the 1‐year period preceding each procedure and was further categorized into quintiles of volume for surgeon and hospital. Multilevel logistic regression models were used to evaluate the effect of surgeon volume, accounting for hospital volume, on mortality after adjusting for patient demographic and comorbid conditions as well as the analogous effect of hospital volume adjusting for surgeon volume. The multilevel models included random effects for surgeon and hospital to account for the clustering of multiple patients within the same surgeon and within the same hospital. Results: We studied 122,495 patients who underwent AAA repair (open: 45,451; EVAR: 77,044). After EVAR, perioperative mortality did not differ by surgeon volume (quintile 1 [0–6 EVARs]: 1.8%; quintile 5 [28–151 EVARs]: 1.6%; P = .29), but decreased with greater hospital volume (quintile 1 [0–9 EVARs]: 1.9%; quintile 5 [49–198 EVARs]: 1.4%; P < .01). After open repair, perioperative mortality decreased with both higher surgeon volume (quintile 1 [0–3 open repairs]: 6.4%; quintile 5 [14–62 open repairs]: 3.8%; P < .01) and hospital volume (quintile 1 [0–5 open repairs]: 6.3%; quintile 5 [14–62 open repairs]: 3.8%; P < .01). After adjustment for other predictors, surgeon volume was not associated with perioperative mortality after EVAR (odds ratio [OR], 0.9; 95% confidence interval [CI], 0.7–1.1); however, hospital volume was associated with higher perioperative mortality (quintile 1: OR, 1.5; 95% CI, 1.2–1.9; quintile 2: OR, 1.3; 95% CI, 1.02–1.6; and quintile 3: OR, 1.2; 95% CI, 1.01–1.5, compared with 5). After open repair, higher surgeon volume was also associated with lower mortality (quintile 1: OR, 1.5; 95% CI, 1.3–1.8; quintile 2: OR, 1.3; 95% CI, 1.1–1.6; and quintile 3: OR, 1.2; 95% CI, 1.1–1.4, compared with 5). Risk of mortality also was higher for patients treated at lower‐volume hospitals (quintile 1: OR, 1.3; 95% CI, 1.1–1.5; quintile 2: OR, 1.3; 95% CI, 1.1–1.5; and quintile 3: OR, 1.2; 95% CI, 1.1–1.4, compared with 5). Conclusions: After EVAR, hospital volume is minimally associated with perioperative mortality, with no such association for surgeon volume. After open AAA repair, surgeon and hospital volume are both strongly associated with mortality. These findings suggest that open surgery should be concentrated in hospitals and surgeons with high volume.

Intraoperative small bowel length measurements and analysis of demographic predictors of increased length

Few studies have measured small bowel length (SBL) in live humans and many textbooks base their “normal” SBL values on cadaver data. Here, we present a series of intraoperative SBL measurements and analyze predictors of increased length. SBL from ligament of Treitz to ileocecal valve was measured in patients undergoing laparotomy for colorectal resection. Patients with Crohns disease and those who had undergone prior bowel resections were excluded. In the 240 patients studied, mean SBL was 506 ± 105 (285–845) cm. Height was positively associated with increased SBL (P < 0.001) and men had longer SBL than women (533 vs. 482 cm, P < 0.001). A multivariate linear regression model using patient sex, age, height and weight was significant (P = 0.001) and the predictors explained 8% of the variance in SBL. In this model, only height was independently predictive of increased SBL (P = 0.03). Correlation results differed between sexes. In men, height correlated with increased SBL (r = 0.20; P = 0.03), whereas in women it did not. In men, age had a positive correlation with SBL at a trend level (r = 0.17; P = 0.08), whereas in women age had a negative correlation with SBL (r = −0.18; P = 0.04). The mean SBL was 506 cm in live patients, as compared with the 600–700 cm range derived from prior cadaver studies. Male sex and height had positive correlations with SBL. SBL may decrease with age in women but not in men. Clin. Anat. 26:827–832, 2013.

Regional variation in patient selection and treatment for lower extremity vascular disease in the Vascular Quality Initiative

Objective: Prior studies on the cause and effect of surgical variation have been limited by utilization of administrative data. The Vascular Quality Initiative (VQI), a robust national clinical registry, provides anatomic and perioperative details allowing a more robust analysis of variation in surgical practice. Methods: The VQI was used to identify all patients undergoing infrainguinal open bypass or endovascular intervention from 2009 to 2014. Asymptomatic patients were excluded. The 16 regional groups of the VQI were used to compare variation in patient selection, operative indication, technical approach, and process measures. χ2 analysis was used to assess for differences across regions where appropriate. Results: A total of 52,373 interventions were included (31%). Of the 16,145 bypasses, 5% were performed for asymptomatic disease, 26% for claudication, 56% for chronic limb‐threatening ischemia (CLI) (61% of these for tissue loss), and 13% for acute limb‐threatening ischemia. Of the 35,338 endovascular procedures, 4% were for asymptomatic disease, 40% for claudication, 46% for CLI (73% tissue loss), and 12% for acute limb‐threatening ischemia. Potentially unwarranted variation included proportion of prosthetic conduit for infrapopliteal bypass in claudication (13%‐41%, median, 29%; P < .001), isolated tibial endovascular intervention for claudication (0.0%‐5.0%, median, 3.0%; P < .001), discharge on antiplatelet and statin (bypass: 62%‐84%; P < .001; endovascular: 63%‐89%; P < .001), and ultrasound guidance for percutaneous access (claudication: range, 7%‐60%; P < .001; CLI: 5%‐65%; P < .001). Notable areas needing further research with significant variation include proportion of CLI vs claudication treated by bypass (38%‐71%; P < .001) and endovascular intervention (28%‐63%; P < .001), and use of closure devices in percutaneous access (claudication; 26%‐76%; P < .001; CLI: 30%‐78%; P < .001). Conclusions: Significant variation exists both in areas where evidence exists for best practice and, therefore, potentially unwarranted variation, and in areas of clinical ambiguity. Quality improvement efforts should be focused on reducing unwarranted variation. Further research should be directed at identifying best practice where no established guidelines and high variation exists.

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.

Follow-Up after Gastric Electrical Stimulation for Gastroparesis

BACKGROUND Gastric electrical stimulation (GES) is used to treat medically refractory gastroparesis. However, there are few large series with outcomes beyond 12 months. This study reports surgical outcomes of GES for patients up to 8 years receiving treatment from a single institution. STUDY DESIGN A prospective database was reviewed from 2003 to 2013 for patients undergoing GES. Baseline patient characteristics were recorded, including age, sex, cause of gastroparesis, gastric emptying, and Hgb A1C. Outcomes variables included nutrition supplementation, additional operations, 30-day morbidity, and mortality. Pre- and postoperative pain and function scores are analyzed over time using generalized estimating equations. Patient outcomes in terms of reoperation rates and types of operations are also reviewed. RESULTS Seventy-nine patients underwent GES with a mean ± SD age of 43 ± 11 years and a BMI of 27 ± 8 kg/m(2). Symptom scores were available for 60 patients: 60 patients at baseline, 52 patients at 1 year, 14 patients during years 2 to 3, and 18 patients during years 4 to 8. Symptom scores decreased considerably in all categories. At 1-year follow-up, 44% and 31% of patients had at least a 25% reduction in symptom distress for functional and pain symptoms, respectively. Preoperatively, 9 patients required nutrition supplementation. After implantation, 34 (43%) patients underwent additional operations, with a mean of 2.15 operations per patient. Generator-related causes were the most common indication for reoperation, including battery exchanges and relocation. Other operations included 8 gastrectomies and 7 median arcuate ligament releases. Postoperatively, 4 patients required supplemental nutrition. There were no 30-day mortalities, but 11 patients died during the study period. CONCLUSIONS Gastric electrical stimulation was significantly associated with reductions in both functional and pain-related symptoms of gastroparesis. Patients who undergo GES have a high likelihood of additional surgery.

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.

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.

30-Day Morbidity and Mortality Outcomes of Prolonged Minimally Invasive Kidney Procedures Compared with Shorter Open Procedures: National Surgical Quality Improvement Program Analysis

BACKGROUND AND PURPOSE Prolonged operative time (ORT) is often considered a drawback to minimally invasive surgery (MIS) because of increased morbidity. Limited data exist comparing long laparoscopic ORT with similar or shorter open ORT. This study aims to identify ORT when a minimally invasive procedure becomes inferior to its open counterpart. METHODS Minimally invasive and open total and partial nephrectomies and nephroureterectomies were identified in the National Surgical Quality Improvement Program (NSQIP) from 2005 to 2012. Procedures were split into open and minimally invasive nephrectomy and then stratified into four ORT groups: 0 to 90 minutes, 91 minutes to 3 hours, 3 to 6 hours, and ≥ 6 hours. Thirty-day mortality and morbidity were analyzed. Univariate analysis was performed using chi-square and Fisher exact tests. Significant univariate results were then tested using stepwise logistic regression, controlling for demographics, comorbidities, and preoperative treatments. RESULTS There were 14,813 patients identified. Both partial and total minimally invasive kidney procedures had significantly improved outcomes compared with open counterparts of similar ORT. In the total nephrectomy group, a minimally invasive approach had a lower rate of surgical site infections, sepsis, pneumonia, return to operating room, and overall length of stay when compared with open procedures of the same duration. Length of hospital stay decreased in MIS regardless of operative time, except when comparing minimally invasive cases longer than 6 hours with open cases less than 90 minutes. Transfusion rates also significantly decreased in minimally invasive total nephrectomy cases. In the partial nephrectomy group, similar outcomes were seen in terms of length of stay and infectious outcomes. Interestingly, transfusion risk was decreased in the open partial nephrectomy group when comparing cases less than 90 minutes with minimally invasive partial nephrectomies lasting 3 to 6 hours; otherwise there was no significant correlation with transfusion risk. CONCLUSIONS Minimally invasive operations are less morbid than open operations of similar ORT. Longer and likely more complex laparoscopic procedures continue to provide a benefit to patients when compared with shorter and possibly less complex open procedures. These data should be considered during a surgeons preoperative and operative decision-making.

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.