Perioperative Infections after Open Abdominal Aortic Aneurysm Repair Lead to Increased Risk of Subsequent Complications.

BACKGROUND: Patients undergoing open abdominal aortic aneurysm (AAA) repair are at risk of perioperative infections that can lead to subsequent complications. Our goal was to understand how an initial infectious complication influences the risk of subsequent complications in this cohort of patients. METHODS: Using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database (2005-2012), we evaluated the relationship between 3 index infectious complications after open elective AAA repair (pneumonia, deep/organ surgical site infection [SSI], and urinary tract infection [UTI]) and subsequent complications. We used 5:1 propensity matching and calculated propensity score to experience to establish matching cohorts for each index complication. This score was based on preoperative variables and number of event-free days. RESULTS: There were 3,991 patients who were identified to have undergone elective open AAA repair in the ACS-NSQIP database. Postoperative index pneumonia was associated with increased risk of unplanned intubation (28.6% vs. 3.5%; odds ratio [OR], 10.9; 95% confidence interval [CI]: 6.7-17.5; P < 0.001), prolonged ventilation (38.5% vs. 6.7%; OR, 8.7; 95% CI: 5.9-13.0; P < 0.001), sepsis (14.3% vs. 3.3%; OR, 4.8; 95% CI: 2.8-8.4; P < 0.001), acute renal failure (9.9% vs. 2.1%; OR, 5.1; 95% CI: 2.6-9.9; P < 0.001), deep vein thrombosis (DVT) (3.8% vs. 1.4%; OR, 2.7; 95% CI: 1.1-7.0; P = 0.035), and mortality (7.1% vs. 3.0%; OR, 2.5; 95% CI: 1.3-4.9; P = 0.009). Postoperative index UTI was associated with increased risk of sepsis (21.4% vs. 0%; OR, 49.2; 95% CI: 14.5-166.8; P < 0.001), pneumonia (10.7% vs. 2.9%; OR, 4.0; 95% CI: 1.8-8.6; P = 0.001), DVT (3.6% vs. 0.4%; OR, 10.0; 95% CI: 1.8-55.5; P = 0.008), and mortality (5.4% vs. 1.8%; OR, 3.0; 95% CI: 1.1-8.5; P = 0.02). Finally, postoperative index deep/organ SSI increased the risk of pneumonia (13.0% vs. 0.9%; OR, 16.7; 95% CI: 1.6-168.2; P = 0.017), prolonged ventilation (21.7% vs. 0.9%; OR, 30.8; 95% CI: 3.4-279.4; P = 0.002), and sepsis (13.0% vs. 0.9%; OR, 16.7; 95% CI: 1.6-168.2; P = 0.017). CONCLUSIONS: A postoperative nosocomial infection after open AAA repair is significantly more likely to lead to serious subsequent complications. Prevention and early identification of infectious index complications and subsequent complications could allow for interventions that could decrease morbidity and mortality.

Hypoalbuminemia Predicts Perioperative Morbidity and Mortality after Infrainguinal Lower Extremity Bypass for Critical Limb Ischemia.

BACKGROUND: Poor nutritional status has been associated with a higher risk of morbidity and mortality in general surgery patients; however, outcomes in vascular surgery patients are unclear. Our goal was to determine the effect of poor nutritional status on perioperative morbidity and mortality after lower extremity bypass (LEB). METHODS: The 2005-2012 National Surgical Quality Improvement Program was analyzed to determine associated complications, mortality, length of stay (LOS), and readmissions for patients with hypoalbuminemia (serum albumin <3.5 g/dL and <2.8 g/dL) undergoing infrainguinal lower extremity bypass for critical limb ischemia. Multivariable analyses were performed to assess associated risk factors while adjusting for possible confounders. RESULTS: There were 5,110 LEB identified with an albumin level recorded. There were 2,327 (45.5%) patients with a low preoperative albumin. Patients with a low albumin were more likely to have diabetes, chronic obstructive pulmonary disease, congestive heart failure, previous myocardial infarction, renal failure, dialysis dependence, hypertension, history of transient ischemic attack or stroke, steroid use, impaired functional status, dyspnea at rest, anemia, prior operations within 30 days, preoperative wounds or infections, and a tibial target (P < 0.05). Multivariable analyses showed that low albumin was independently associated with increased mortality (odds ratio [OR]: 1.8, 95% confidence interval [95% CI]: 1.3-2.6, P = 0.001), return to the operating room (OR: 1.4, 95% CI: 1.2-1.6, P < 0.001), and increased LOS (MR: 1.2, 95% CI: 1.1-1.2, P < 0.001). When compared with patients with normal albumin, patients with more severe hypoalbuminemia, less than 2.8 g/dL, showed further increased risk of mortality (OR: 2.5, 95% CI: 1.6-3.8), return to the operating room (OR: 1.6, 95% CI: 1.3-2.0), and prolonged LOS (MR: 1.2, 95% CI: 1.2-1.3). CONCLUSIONS: Poor preoperative hypoalbuminemia is associated with morbidity and mortality after infrainguinal lower extremity bypass for critical limb ischemia. Evaluation and optimization of nutritional status should be performed preoperatively in this high risk population.

Preoperative hypoalbuminemia is associated with poor clinical outcomes after open and endovascular abdominal aortic aneurysm repair.

OBJECTIVE: The effect of preoperative malnutrition on outcomes in patients undergoing major vascular surgery is unclear. We investigated the effects of preoperative hypoalbuminemia, a marker for malnutrition, on outcomes after open abdominal aortic aneurysm repair (OAR) and endovascular abdominal aortic aneurysm repair (EVAR). METHODS: Patients undergoing OAR or EVAR were identified in the 2005 to 2012 American College of Surgeons National Surgical Quality Improvement Program database and stratified into three groups: normal albumin (serum albumin >3.5 g/dL), moderate hypoalbuminemia (2.8-3.5 g/dL), and severe hypoalbuminemia (<2.8 g/dL). Multivariable analyses were performed to assess the association of preoperative hypoalbuminemia with 30-day morbidity and mortality. RESULTS: We identified 15,002 patients with a recorded preoperative serum albumin who underwent OAR (n = 4956) or EVAR (n = 10,046). Patients in both cohorts with hypoalbuminemia had a higher burden of comorbidity. In OAR patients, multivariable analyses demonstrated that moderate hypoalbuminemia was associated with an increased risk of 30-day mortality (odds ratio [OR], 1.32; 95% confidence interval [CI], 1.02-1.70) and postoperative length of stay (LOS; means ratio [MR], 1.10; 95% CI, 1.04-1.16), whereas severe hypoalbuminemia was associated with increased 30-day mortality (OR, 1.92; 95% CI, 1.37-2.70), reoperation ≤30 days (OR, 1.80; 95% CI, 1.32-2.48), pulmonary complications (OR, 1.40; 95% CI, 1.06-1.86), and postoperative LOS (MR, 1.33; 95% CI, 1.21-1.45). In EVAR patients, moderate hypoalbuminemia was associated with an increased risk of 30-day mortality (OR, 1.90; 95% CI, 1.38-2.62), pulmonary complications (OR, 1.61; 95% CI, 1.26-2.04), reoperation ≤30 days (OR, 1.39; 95% CI, 1.12-1.74), and postoperative LOS (MR, 1.23; 95% CI, 1.18-1.29), whereas severe hypoalbuminemia was associated with increased 30-day mortality (OR, 2.98; 95% CI, 1.96-4.53), pulmonary complications (OR, 1.88; 95% CI, 1.32-2.67), reoperation ≤30 days (OR, 1.54; 95% CI, 1.08-2.19), and postoperative LOS (MR, 1.52; 95% CI, 1.40-1.65). CONCLUSIONS: Preoperative hypoalbuminemia is associated with increased postoperative morbidity and mortality in a severity-dependent manner among patients undergoing OAR or EVAR. Evaluation and optimization of nutritional status should be performed preoperatively in this high-risk population.

Index complications predict secondary complications after infrainguinal lower extremity bypass for critical limb ischemia.

OBJECTIVE: Patients undergoing lower extremity bypass (LEB) are at high risk of perioperative complications that can lead to a cascade of secondary complications. Our goal was to understand the association of index complications with secondary complications after LEB. METHODS: The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database from 2005 to 2012 was used to analyze secondary complications after five index complications after LEB: deep/organ space surgical site infection, urinary tract infection (UTI), myocardial infarction (MI), pneumonia, and acute renal failure (ARF). Index cohorts were developed with 5:1 propensity matching for comparison. This score was based on preoperative variables and event-free days. RESULTS: We evaluated 20,230 LEB patients. Postoperative index surgical site infection increased the risk of secondary ARF (odds ratio [OR], 4.0; 95% confidence interval [CI], 1.1-15.0), pneumonia (OR, 2.7; 95% CI, 1.0-7.4), UTI (OR, 3.1; 95% CI, 1.3-7.5), cardiac arrest (OR, 4.4; 95% CI, 1.6-12.2), wound disruption (OR, 10.5; 95% CI, 6.7-16.6), unplanned intubation (OR, 5.1; 95% CI, 2.0-12.8), prolonged ventilation (OR, 5.9; 95% CI, 2.0-17.6), sepsis (OR, 16.2; 95% CI, 10.2-25.6), and mortality (OR, 3.5; 95% CI, 1.7-7.1). Postoperative index UTI was associated with pneumonia (OR, 5.6; 95% CI, 2.7-11.6), sepsis (OR, 7.8; 95% CI, 5.1-11.8), and mortality (OR, 2.7; 95% CI, 1.3-5.3). Postoperative index MI was associated with secondary ARF (OR, 8.7; 95% CI, 3.8-20.1), pneumonia (OR, 4.9; 95% CI, 2.7-8.8), cardiac arrest (OR; 7.4; 95% CI; 4.0-13.5), deep venous thrombosis (OR, 3.9; 95% CI, 1.7-9.1), unplanned intubation (OR, 12.2; 95% CI, 7.3-20.3), prolonged intubation (OR, 12.2; 95% CI, 6.4-23.2), sepsis (OR, 2.2; 95% CI, 1.2-3.8), and mortality (OR, 5.6; 95% CI, 3.6-8.5). Postoperative index pneumonia was associated with secondary ARF (OR, 25.5; 95% CI, 3.0-219.3), MI (OR, 7.6; 95% CI, 3.2-18.0), UTI (OR, 4.3; 95% CI, 2.0-9.0), cardiac arrest (OR, 5.2; 95% CI, 2.0-13.2), deep venous thrombosis (OR, 7.7; 95% CI, 2.1-27.4), unplanned intubation (OR, 14.7; 95% CI, 8.3-26.1), prolonged ventilation (OR, 26.0; 95% CI, 11.8-56.9), sepsis (OR, 7.2; 95% CI, 4.0-12.8), and mortality (OR, 6.0; 95% CI, 3.7-10.0). Last, postoperative index ARF was associated with increased risk of secondary pneumonia (OR, 7.16; 95% CI, 2.6-20.0), cardiac arrest (OR, 15.5; 95% CI, 1.6-150.9), unplanned intubation (OR, 6.2; 95% CI, 2.3-16.8), prolonged ventilation (OR, 8.8; 95% CI, 3.4-22.4), and mortality (OR, 8.8; 95% CI, 3.4-22.4). CONCLUSIONS: A postoperative index complication after LEB is significantly more likely to lead to serious secondary complications. Prevention and early identification of index complications and subsequent secondary complications could decrease morbidity and mortality.

Thirty-day and 90-day hospital readmission after outpatient upper extremity hemodialysis access creation.

OBJECTIVE: Patients with end-stage renal disease have multiple comorbidities and are at increased risk for postoperative complications and resource utilization. Our goal was to determine the rate and causes of 30-day and 90-day hospital readmissions after the creation of outpatient hemodialysis access. METHODS: We retrospectively reviewed all outpatient upper extremity hemodialysis access creations performed at our medical center from 2008 to 2015. Readmission was defined as any inpatient status admission ≤30 and 90 days. Reasons for such admissions were analyzed, and multivariate analyses assessed risk factors. RESULTS: We identified 537 patients (60% male). Average age was 59 years. Access type included radiocephalic (4.5%), brachiocephalic (50.7%), brachiobasilic (22.5%), and prosthetic (20%) arteriovenous fistulas. The 90-day mortality rate was 0.7%. Postoperative hospital readmission rates were 25.5% at 30 days and 47.7% at 90 days. Reasons for admission were access related in 10.9% and dialysis catheter related in 6.9%. Other reasons for admission included shortness of breath/volume overload (15.8%), gastrointestinal (11.9%), cardiac/chest pain (10.9%), unrelated infectious causes (11.9%), failure to thrive (5%), altered mental status (4%), electrolyte abnormalities (3%), and musculoskeletal (2.5%). Preoperative predictors of all cause 30-day readmission included dementia (odds ratio [OR], 5.76; 95% confidence interval [CI], 1.34-24.8; P = .018), hypertension (OR, 3.92; 95% CI, 1.07-14.4; P = .039), chronic obstructive pulmonary disease (OR, 2.19; 95% CI, 1.01-4.76; P = .046), and current smoking (OR, 2.14; 95% CI, 1.32-3.47; P = .002). Predictors of all cause 90-day readmission were hepatic insufficiency (OR, 6.08; 95% CI, 1.2-30.8; P = .029), hypertension (OR, 3.43; 95% CI, 1.36-8.65; P = .009), black race (OR, 2.47; 95% CI, 1.48-4.14; P = .001), Hispanic ethnicity (OR, 2.04; 95% CI, 1.01-4.11; P = .046), and obesity (OR, 1.5; 95% CI, 1.02-2.19; P = .039). Predictors of 90-day access-related readmission included chronic obstructive pulmonary disease (OR, 5.27; 95% CI, 1.38-20.0; P = .015), previous stroke (OR, 3.76; 95% CI, 1.5-9.4; P = .005), being on dialysis at time of the operation (OR, 2.8; 95% CI, 1.17-6.84; P = .022), and prosthetic graft placement (OR, 2.86; 95% CI, 1.07-7.6; P = .036). An additional 9.7% had at least one emergency department presentation ≤90 days but were not admitted. CONCLUSIONS: Patients undergoing placement of hemodialysis access are at high risk for readmission mostly from causes unrelated to their operation. This has an effect for global care for these patients as well as care of these patients in accountable care organizations.

Characterization of Planned and Unplanned 30-Day Readmissions Following Vascular Surgical Procedures.

OBJECTIVE: Thirty-day readmission is increasingly used as a quality of care indicator. Patients undergoing vascular surgery have historically been at high risk for readmission. We analyzed hospital readmission details to identify patients at high risk for readmission in order to better understand these readmissions and improve resource utilization in this patient population. METHODS: A retrospective review and analysis of our medical center's admission and discharge data were conducted from October 2012 to March 2015. All patients who were discharged from the vascular surgery service and subsequently readmitted as an inpatient within 30 days were included. RESULTS: We identified 649 vascular surgery discharges with 135 (21%) readmissions. Common comorbidities were diabetes (56%), coronary artery disease (40%), congestive heart failure (CHF; 24%), and chronic obstructive pulmonary disease (19%). Index vascular operations included open lower extremity procedures (39%), diagnostic angiograms (35%), endovascular lower extremity procedures (16%), dialysis access procedures (7%), carotid/cerebrovascular procedures (7%), amputations (6%), and abdominal aortic procedures (5%). Average index length of stay (LOS) was 7.48 days (±6.73 days). Reasons for readmissions were for medical causes (43%), surgical complications (35.5%), and planned procedures (21.5%). Reasons for medical readmissions most commonly included malaise or failure to thrive (28%), unrelated infection (24%), and hypoxia/CHF complications (21%). Common surgical causes for readmission were surgical site infections (69%), graft failure (19%), and bleeding complications (8%). Of the planned readmissions, procedures were at the same site (79%), a different site (14%), and planned podiatry procedures (7%). Readmission LOS was on average 7.43 days (±7.22 days). CONCLUSION: Causes for readmission of vascular surgery patients are multifactorial. Infections, both related and unrelated to the surgical site, remain common reasons for readmission and represent an opportunity for improvement strategies. Improved understanding of readmissions following vascular surgery could help adjust policy benchmarks for targeted readmission rates and help reduce resource utilization.

Assessment of open operative vascular surgical experience among general surgery residents.

BACKGROUND: General surgeons have traditionally performed open vascular operations. However, endovascular interventions, vascular residencies, and work-hour limitations may have had an impact on open vascular surgery training among general surgery residents. We evaluated the temporal trend of open vascular operations performed by general surgery residents to assess any changes that have occurred. METHODS: The Accreditation Council for Graduate Medical Education's database was used to evaluate graduating general surgery residents' cases from 1999 to 2013. Mean and median case volumes were analyzed for carotid endarterectomy, open aortoiliac aneurysm repair, and lower extremity bypass. Significance of temporal trends were identified using the R(2) test. RESULTS: The average number of carotid endarterectomies performed by general surgery residents decreased from 23.1 ± 14 (11.6 ± 9 chief, 11.4 + 10 junior) cases per resident in 1999 to 10.7 ± 9 (3.4 ± 5 chief, 7.3 ± 6 junior) in 2012 (R(2) = 0.98). Similarly, elective open aortoiliac aneurysm repairs decreased from 7.4 ± 5 (4 ± 4 chief, 3.4 ± 4 junior) in 1999 to 1.3 ± 2 (0.4 ± 1 chief, 0.8 ± 1 junior) in 2012 (R(2) = 0.98). The number of lower extremity bypasses decreased from 21 ± 12 (9.5 ± 7 chief, 11.8 ± 9 junior) in 1999 to 7.6 ± 2.6 (2.4 ± 1.3 chief, 5.2 + 1.8 junior) in 2012 (R(2) = 0.94). Infrapopliteal bypasses decreased from 8.1 ± 3.8 (3.5 ± 2.2 chief, 4.5 ± 2.9 junior) in 2001 to 3 ± 2.2 (1 ± 1.6 chief, 2 ± 1.6 junior) in 2012 (R(2) = 0.94). CONCLUSIONS: General surgery resident exposure to open vascular surgery has significantly decreased. Current and future graduates may not have adequate exposure to open vascular operations to be safely credentialed to perform these procedures in future practice without advanced vascular surgical training.

BMP9 induces EphrinB2 expression in endothelial cells through an Alk1-BMPRII/ActRII-ID1/ID3-dependent pathway: implications for hereditary hemorrhagic telangiectasia type II.

ALK1 (ACVRL1) is a member of the TGFß receptor family and is expressed predominantly by arterial endothelial cells (EC). Mutations in ACVRL1 are responsible for hereditary hemorrhagic telangiectasia type 2 (HHT2), a disease manifesting as fragile vessels, capillary overgrowth, and numerous arterio-venous malformations. Arterial EC also express EphrinB2, which has multiple roles in vascular development and angiogenesis and is known to be reduced in ACVRL1 knockout mice. Using an in vitro angiogenesis model we find that the Alk1 ligand BMP9 induces EphrinB2 in EC, and this is entirely dependent on expression of Alk1 and at least one of the co-receptors BMPRII or ActRII. BMP9 induces both ID1 and ID3, and both are necessary for full induction of EphrinB2. Loss of Alk1 or EphrinB2 results in increased arterial-venous anastomosis, while loss of Alk1 but not EphrinB2 results in increased VEGFR2 expression and enhanced capillary sprouting. Conversely, BMP9 blocks EC sprouting and this is dependent on Alk1, BMPRII/ActRII and ID1/ID3. Finally, notch signaling overcomes the loss of Alk1-restoring EphrinB2 expression in EC, and curbing excess sprouting. Thus, in an in vitro model of HHT2, loss of Alk1 blocks BMP9 signaling, resulting in reduced EphrinB2 expression, enhanced VEGFR2 expression, and misregulated EC sprouting and anastomosis.