Analysis of Early Lower Extremity Re-amputation.

BACKGROUND: Data is scarce regarding the need for early re-amputation to a higher anatomic level. This study seeks to define outcomes and risk factors for re-amputation. METHODS: Patients undergoing primary major lower extremity amputation were identified within the 2012-2016 ACS-NSQIP database. Demographics, outcomes, and peri-operative characteristics were compared, and multivariable logistic regression model was used to determine association with early re-amputation. RESULTS: Over a 4-year period, 8306 below knee amputations and 6367 above knee amputations were identified. Thirty-day re-amputation occurred in 262 patients (1.8%) and was associated with increased length of stay (12.9 vs. 7.3 days, P < 0.001), higher rates of readmission (64.9% vs. 13.6%, P < 0.001), and overall complications (69.5% vs. 39.3%, P < 0.01). On multivariable analysis, advanced age (OR 1.02, CI 1.01-1.03), smoking (OR 1.75, CI 1.32-2.33), dialysis dependence (OR 1.67, CI 1.23-2.26), preoperative septic shock (OR 2.53, CI 1.29-4.97), and bleeding disorders (OR 1.72, CI 1.34-2.22) were associated with early re-amputation. CONCLUSIONS: Thirty-day re-amputation rates are low, but are associated with significant morbidity, prolonged hospitalization, and frequent readmissions.

Diabetes and Its Effect on Abdominal Aortic Aneurysm Growth Rate in Hispanic Patients.

BACKGROUND: The growth rate of abdominal aortic aneurysms (AAA) can vary depending on age, baseline diameter, blood pressure, race, and history of smoking. Paradoxically, previous studies show evidence of a protective effect of diabetes on the rate of AAA expansion despite its well-established role in the morbidity and mortality of cardiovascular disease. This study aims to investigate the impact diabetes plays on AAA growth within a Hispanic population. METHODS: Data were collected from patients who were predominantly Mexican-American at a single hospital site. Baseline and follow-up measures for AAA diameter were obtained from serial imaging studies. Demographics, medical history, the presence of type 2 diabetes, and medication use were extracted from hospital records. Linear mixed-effects growth models were used to calculate the overall AAA growth rate and to assess the difference in AAA growth rate between demographics, comorbidities, and medication use. RESULTS: The study comprised 201 patients (70.4% male) with a mean baseline age of 79.1 years, of whom 43.2% were diabetic. The average monthly AAA growth rate across all study participants was 0.15 mm (SE = 0.02 mm). Independently, the average AAA expansion rate for the diabetic and nondiabetic groups was 0.07 mm (SE = 0.04 mm) and 0.21 mm (SE = 0.03 mm) per month, respectively. This demonstrates a 65% lower linear AAA expansion rate per month in patients with diabetes. CONCLUSIONS: This study confirms a difference of AAA physiology between diabetics and nondiabetics in the Hispanic community. The observed significant difference in AAA growth rate may be a combination of factors associated with race/ethnicity, prevalence of diabetes mellitus, and low compliance with diabetic control exhibited in the Mexican-American population.

Thirty-day outcomes after fenestrated endovascular repair are superior to open repair of abdominal aortic aneurysms involving visceral vessels.

OBJECTIVE: Although few studies have reported outcomes after branched or fenestrated endovascular aortic aneurysm repair (FEVAR) of abdominal aortic aneurysms involving visceral vessels (AAA-Vs), no multi-institutional study has compared FEVAR with open surgery (OS) for AAA-Vs. Our objective was to compare 30-day outcomes after FEVAR vs OS for AAA-Vs. METHODS: Patients who underwent FEVAR (n = 535) and OS (n = 1207) for elective AAA-Vs were identified from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) 2008 to 2013 database. Thoracoabdominal aneurysms were excluded. Univariable and multivariable logistic regression analyses were performed. RESULTS: There were more men (82% vs 72%; P < .0001), diabetic patients (16% vs 11%; P = .005), patients with dependent functional status (4% vs 2%; P = .002), and nonsmokers (70% vs 56%; P < .0001) in the FEVAR group vs OS. There was no difference in rates of chronic obstructive pulmonary disease, cardiac history, peripheral artery disease, hypertension, and dialysis (P > .05). FEVAR had fewer major postoperative pulmonary complications (3.0% vs 19.0%; P < .0001), less renal failure requiring dialysis (1.9% vs 6.4%; P < .0001), less frequent cardiac arrest or myocardial infarction (2.2% vs 5.8%; P = .001), less bleeding with major transfusion (17.4% vs 50.2%; P < .0001), and decreased incidence of return to the operating room (4.5% vs 9.6%; P < .0001) and death (2.4% vs 4.7%; P = .02). The median length of stay was also significantly shorter for FEVAR (2 days vs 7 days; P < .0001). On multivariable analyses, OS was associated with higher risk than FEVAR for 30-day death (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.3-5.0), pulmonary complications (OR, 8.8; 95% CI, 5.1-15.0), cardiac complications (OR, 3.4; 95% CI, 1.8-6.6), renal failure needing dialysis (OR, 3.8; 95% CI, 1.9-7.7), and return to the operating room (OR 2.5; 95% CI, 1.6-4.0). CONCLUSIONS: FEVAR is associated with a lower risk for 30-day mortality and adverse events compared with OS for AAA-Vs.

Morbidity and mortality after use of iliac conduits for endovascular aortic aneurysm repair.

OBJECTIVE: Although placement of an open iliac conduit for endovascular aortic aneurysm repair (EVAR) is generally felt to result in higher morbidity and mortality, published literature is scarce. Our objective was to assess 30-day outcomes after elective EVAR with an open iliac conduit using a multi-institutional database. METHODS: Patients who underwent elective EVAR (n = 14,339) for abdominal aortic aneurysm were identified from the American College of Surgeons National Surgical Quality Improvement Program 2005 to 2011 database. Univariable and multivariable logistic regression analyses were performed. RESULTS: An open iliac conduit was used in 231 patients (1.6%), and the remainder had femoral exposure or percutaneous EVAR. Women comprised 32% of patients with iliac conduits in contrast to 17% of those without iliac conduits. Patients with iliac conduits were older and had a lower body mass index. Univariable analysis showed patients with open iliac conduits had a higher incidence of postoperative pneumonia (3.0% vs 1.1%), ventilator dependence (4.8% vs 1.0%), renal failure (3.0% vs 0.7%), cardiac arrest or myocardial infarction (5.2% vs 1.1%), return to the operating room (9.1% vs 3.7%), major morbidity (16.0 vs 6.6%), and death (3.0% vs 0.9%). On multivariable analysis, the use of open iliac conduits was associated with higher risk of 30-day mortality (odds ratio, 2.7; 95% confidence interval, 1.2-6.0) and 30-day major morbidity (odds ratio, 2.3; 95% confidence interval, 1.6-3.3). CONCLUSIONS: Patients with open iliac conduits for EVAR are more likely to be female and have higher postoperative morbidity and mortality. For patients with complex iliac artery disease, conduits are a viable alternative after EVAR to be performed, albeit at an increased risk. These data do suggest the need for lower-profile grafts and other alternative strategies for navigating complex iliac artery disease.

Preoperative frailty Risk Analysis Index to stratify patients undergoing carotid endarterectomy.

OBJECTIVE: Rapid and objective preoperative assessment of patients undergoing carotid endarterectomy (CEA) remains problematic. Preoperative variables correlate with increased morbidity and mortality, yet no easily implemented tool exists to stratify patients. We determined the relationship between our fully implemented frailty-based bedside Risk Analysis Index (RAI) and complications after CEA. METHODS: Patients undergoing CEA in the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database from 2005 to 2011 were included. Variables of frailty RAI were matched to preoperative NSQIP variables, and outcomes including stroke, mortality, myocardial infarction (MI), and length of stay were analyzed. We further analyzed patients who were symptomatic and asymptomatic before CEA. RESULTS: With use of the NSQIP database, 44,832 patients undergoing CEA were analyzed (17,696 [39.5%] symptomatic; 27,136 [60.5%] asymptomatic). Increasing frailty RAI score correlated with increasing stroke, death, and MI (P < .0001) as well as with length of stay. RAI demonstrated increasing risk of stroke and death on the basis of risk stratification (low risk [0-10], 2.1%; high risk [>10], 5.0%). Among patients undergoing CEA, 88% scored low (<10) on the RAI. In symptomatic patients, the risk of stroke and death for patients with a score of ≤10 is 2.9%, whereas if the RAI score is 11 to 15, it is 5.0%; 16 to 20, 6.9%; and >21, 8.6%. In asymptomatic patients, the risk of stroke and death for patients with a score of ≤10 is 1.6%, whereas if the RAI score is 11 to 15, it is 2.9%; 16 to 20, 5.2%; and >21, 6.2%. CONCLUSIONS: Frailty is a predictor of increased stroke, mortality, MI, and length of stay after CEA. An easily implemented RAI holds the potential to identify a limited subset of patients who are at higher risk for postoperative complications and may not benefit from CEA.

A comparison of open surgery versus endovascular repair of unstable ruptured abdominal aortic aneurysms.

OBJECTIVE: Two randomized trials to date have compared open surgery (OS) and endovascular (EVAR) repair for ruptured abdominal aortic aneurysm (rAAA); however, neither addressed optimal management of unstable patients. Single-center reports have produced conflicting data regarding the superiority of one vs the other, with the lack of statistical power due to low patient numbers. Furthermore, previous studies have not delineated between the outcomes of stable patients with a contained rupture vs those patients with instability. Our objective was to compare 30-day outcomes in patients undergoing OS vs EVAR for all rAAAs, focusing specifically on patients with instability. METHODS: Patients who underwent repair of rAAA were identified from the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database (2005 to 2010). Unstable patients with rupture were identified as those who were American Society of Anesthesiologists Physical Status Classification 4 or 5 requiring emergency repair with at least one of the following: preoperative shock, preoperative transfusion of >4 units, preoperative intubation, or preoperative coma or impaired sensorium. Univariable and multivariable logistic regression analyses were performed. RESULTS: Of the 1447 patients with rAAA, 65.5% underwent OS and 34.5% EVAR. Forty-five percent were unstable, and for these patients, OS was performed in 71.3% and EVAR in 28.7%. The 30-day mortality rate was 47.9% (OS, 52.8%; EVAR, 35.6%; P < .0001) for unstable rAAAs and was 22.4% for stable rAAAs (OS, 26.3%; EVAR, 16.4%; P = .001). Amongst patients with unstable rAAA, 26% had a myocardial infarction or cardiac arrest ≤ 30 days (OS, 29.0%; EVAR, 19.1%; P = .006), and 17% needed postoperative dialysis (OS, 18.7%; EVAR, 12.8%; P = .04). Amongst patients with stable rAAA, 13.6% had a myocardial infarction or cardiac arrest ≤ 30 days (OS, 14.9%; EVAR, 11.6%; P = .20), and 11.5% needed postoperative dialysis (OS, 13.3%; EVAR, 8.7%; P = .047). Multivariable analyses showed OS was a predictor of 30-day mortality for unstable rAAA (odds ratio, 1.74; 95% confidence interval, 1.16-2.62) and stable rAAA (odds ratio, 1.64; 95% confidence interval, 1.10-2.43). CONCLUSIONS: Approximately one-third of patients treated for rAAA undergo EVAR in NSQIP participating hospitals. Not surprisingly, unstable patients have less favorable outcomes. In both stable and unstable rAAA patients, EVAR is associated with a diminished 30-day mortality and morbidity.

Clinical characteristics associated with readmission among patients undergoing vascular surgery.

OBJECTIVE: Readmission after a vascular surgery intervention is frequent, costly, and often considered preventable. Vascular surgery outcomes have recently been scrutinized by Medicare because of the high rates of readmission. We determined patient and clinical characteristics associated with readmission in a cohort of vascular surgery patients. METHODS: From 2009 to 2013, the medical records of all patients (n = 2505) undergoing interventions by the vascular surgery service at a single tertiary care institution were retrospectively reviewed. Sociodemographic and clinical characteristics were examined for association with 30-day readmission to the same institution. RESULTS: The 30-day readmission rate to the same institution was 9.7 % (n = 244). Procedures most likely to result in readmission were below-knee (25%), foot (22%), and toe amputations (19%), as well as lower extremity revascularization (22%). Patients covered by Medicaid (16.8%) and Medicare (10.0%) were most likely to be readmitted, followed by fee-for-service (9.5%), self-pay (8.0%), and health maintenance organizations (5.5%; P < .05). Patients urgently admitted were more likely to be readmitted (16.2%) than those electively admitted (9.1%; P < .01). Patient severity as rated using the All Patient Refined Diagnosis Related Groups software (3M Health Information Systems, Wallingford, Conn) predicted readmission (16.2% high vs 6.2% low severity; P < .01). Initial length of stay was longer for readmitted than nonreadmitted patients (8.5 vs 6.1 days, respectively; P < .01). Intensive care unit admission during the initial hospitalization was associated with higher readmission rates in univariable analysis (18.3% with vs 9.5% without intensive care unit stay; P < .05). Discharge destination was also a strong predictor of readmission (rehabilitation, 19.2%; skilled nursing facility, 16.2%; home, 6.2%; P < .01). The effects of urgent admission, proximity to hospital, length of stay, lower extremity open procedure or amputation, and discharge destination persisted in multivariable logistic regression (P < .05). CONCLUSIONS: To reduce readmission rates effectively, institutions must identify high-risk patients. Efforts should focus on subgroups undergoing selected interventions (amputations, lower extremity revascularization), those with urgent admissions, and patients with extended hospital stays. Patients in need of postacute care upon discharge are especially prone to readmission, requiring special attention to discharge planning and coordination of postdischarge care. By focusing on subgroups at risk for readmission, preventative resources can be efficiently targeted.

Unplanned readmissions after vascular surgery.

OBJECTIVE: Existing literature on readmission after vascular surgery is limited. The upcoming reduction in Medicare reimbursement for institutions with high readmission rates mandates an accurate understanding of this issue. In this study, we characterize the frequency and causes of 30-day unplanned readmissions after elective vascular surgery. METHODS: Patients who underwent elective carotid endarterectomy (CEA), endovascular aortic repair (EVAR), open abdominal aortic aneurysm (oAAA) repair, or infrainguinal bypass grafting (BPG) were identified from the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) 2011 database (n = 11,246). Multivariable logistic regression was used to determine variables that contributed to 30-day unplanned readmissions for each surgery type. RESULTS: The unadjusted unplanned readmission rates after the four vascular procedures ranged from 6.5% for CEA to 15.7% for BPG. In multivariable analyses, patient comorbidities were associated with unplanned readmission after BPG and CEA (P < .05), whereas postoperative complications were more consistently associated with unplanned readmission after EVAR and oAAA repair (P < .05). For all procedures, complications leading to readmission developed more frequently after discharge. Thirty-day mortality was significantly higher in readmitted patients after BPG (1.9% vs 0.3%), EVAR (3.9% vs 0.1%), and CEA (2.2% vs 0.2%; P < .001 for each), but not after oAAA repair. CONCLUSIONS: Select comorbidities and postoperative complications contribute to unplanned readmissions after vascular surgery. The characteristics of readmitted patients vary with the type of procedure. Interventions designed to mitigate these factors have the potential to reduce unplanned readmissions but likely need to vary with the type of vascular treatment.

Postdischarge outcomes after endovascular abdominal aortic aneurysm repair.

OBJECTIVE: Perioperative outcomes after endovascular repair (EVAR) of abdominal aortic aneurysms (AAA) have been rigorously studied; however, inpatient and postdischarge outcomes have not been separately analyzed. The objective of this study was to examine postdischarge 30-day outcomes after elective EVAR. METHODS: Patients who underwent an elective EVAR for AAA (n = 11,229) were identified from the American College of Surgeons 2005-2010 National Surgical Quality Improvement Project database. Univariable and multivariable logistic regression analyses were performed. RESULTS: The median length of hospital stay was 2 days (interquartile range, 1-3 days). Overall 30-day mortality was 1.0% (n = 117), with 31% (n = 36) of the patients dying after discharge. Overall 30-day morbidity was 10.7% (n = 1204), with 40% (n = 500) of the morbidities being postdischarge. The median time of death and complication was 9 and 3 days, respectively, after surgery. Eighty-eight percent of the wound infections (n = 205 of 234), 33% of pneumonia (n = 44 of 133), and 55% of venous thromboembolism (n = 36 of 65) were postdischarge. Multivariable analyses showed age, congestive heart failure, admission from nursing facility, postoperative pneumonia, myocardial infarction, and renal failure were independently associated with postdischarge mortality, and peripheral arterial disease, female gender, previous cardiac surgery, age, smoking, and diabetes with postdischarge morbidity (P < .05 for all). CONCLUSIONS: Patient characteristics associated with a higher risk for postdischarge adverse events after EVAR were identified. Whether improved predischarge surveillance and close postdischarge follow-up of identified high-risk patients will further improve 30-day outcomes after EVAR needs to be prospectively studied.

Preoperative anemia is an independent predictor of postoperative mortality and adverse cardiac events in elderly patients undergoing elective vascular operations.

OBJECTIVE: The objective of this study was to assess the impact of preoperative anemia (hematocrit <39%) on postoperative 30-day mortality and adverse cardiac events in patients 65 years or older undergoing elective vascular procedures. BACKGROUND: Preoperative anemia is associated with adverse outcomes after cardiac surgery, but its association with postoperative outcomes after open and endovascular procedures is not well established. Elderly patients have a decreased tolerance to anemia and are at high risk for complications after vascular procedures. METHODS: Patients (N = 31,857) were identified from the American College of Surgeons' 2007-2009 National Surgical Quality Improvement Program-a prospective, multicenter (>250) database maintained across the United States. The primary and secondary outcomes of interest were 30-day mortality and a composite end point of death or cardiac event (cardiac arrest or myocardial infarction), respectively. RESULTS: Forty-seven percent of the study population was anemic. Anemic patients had a postoperative mortality and cardiac event rate of 2.4% and 2.3% in contrast to the 1.2% and 1.2%, respectively, in patients with hematocrit within the normal range (P < 0.0001). On multivariate analysis, we found a 4.2% (95% confidence interval, 1.9-6.5) increase in the adjusted risk of 30-day postoperative mortality for every percentage point of hematocrit decrease from the normal range. CONCLUSIONS: The presence and degree of preoperative anemia are independently associated with 30-day death and adverse cardiac events in patients 65 years or older undergoing elective open and endovascular procedures. Identification and treatment of anemia should be important components of preoperative care for patients undergoing vascular operations.

A mathematical evaluation of hemodynamic parameters after carotid eversion and conventional patch angioplasty.

Carotid endarterectomy has a long history in stroke prevention, yet controversy remains concerning optimal techniques. Two methods frequently used are endarterectomy with patch angioplasty (CEAP) and eversion endarterectomy (CEE). The objective of this study was to compare hemodynamics-related stress and strain distributions between arteries repaired using CEAP and CEE. Mathematical models were based on in vivo three-dimensional arterial geometry, pulsatile velocity profiles, and intraluminal pressure inputs obtained from 16 patients with carotid artery disease. These data were combined with experimentally derived nonlinear, anisotropic carotid artery mechanical properties to create fluid-structure interaction models of CEAP and CEE. These models were then used to calculate hemodynamic parameters thought to promote recurrent disease and restenosis. Combining calculations of stress and strain into a composite risk index, called the integral abnormality factor, allowed for an overall comparison between CEAP and CEE. CEE demonstrated lower mechanical stresses in the arterial wall, whereas CEAP straightened the artery and caused high stress and strain concentrations at the suture-artery interface. CEAP produced a larger continuous region of oscillatory, low-shear, vortical flow in the carotid bulb. There was a more than two-fold difference in the integral abnormality factor, favoring CEE. In conclusion, in a realistically simulated carotid artery, fluid-structure interaction modeling demonstrated CEE to produce less mechanical wall stress and improved flow patterns compared with CEAP. Clinical validation with larger numbers of individual patients will ultimately be required to support modeling approaches to help predict arterial disease progression and comparative effectiveness of reconstruction methods and devices.

Risk index for predicting perioperative stroke, myocardial infarction, or death risk in asymptomatic patients undergoing carotid endarterectomy.

OBJECTIVE: The latest guidelines recommend performance of carotid endarterectomy (CEA) on asymptomatic patients with high-grade carotid stenosis, only if the combined perioperative stroke, myocardial infarction (MI), or death risk is ≤3%. Our objective was to develop and validate a risk index to estimate the combined risk of perioperative stroke, MI, or death in asymptomatic patients undergoing elective CEA. METHODS: Asymptomatic patients who underwent an elective CEA (n = 17,692) were identified from the 2005-2010 National Surgical Quality Improvement Program, a multicenter, prospective database. Multivariable logistic regression analysis was performed with primary outcome of interest being the composite of any stroke, MI, or death during the 30-day periprocedural period. Bootstrapping was used for internal validation. A risk index was created by assigning weighted points to each predictor using the ß-coefficients from the regression analysis. RESULTS: Fifty-eight percent of the patients were men with a median age of 72 years. Thirty-day incidences of stroke, MI, and death were 0.9% (n = 167), 0.6% (n = 108), and 0.4% (n = 72), respectively. The combined 30-day stroke, MI, or death incidence was 1.8% (n = 324). On multivariable analysis, six independent predictors were identified and a risk index created by assigning weighted points to each predictor using the ß-coefficients from the regression analysis. The predictors included age in years (<60: 0 point; 60-69: -1 point; 70-79: -1 point; ≥80: 2 points), dyspnea (2 points), chronic obstructive pulmonary disease (3 points), previous peripheral revascularization or amputation (3 points), recent angina within 1 month (4 points), and dependent functional status (5 points). Patients were classified as low (<3%), intermediate (3%-6%), or high (>6%) risk for combined 30-day stroke, MI, or death, based on a total point score of <4, 4-7, and >7, respectively. There were 15,249 patients (86.2%) in the low-risk category, 2233 (12.6%) in the intermediate-risk category, and 210 (1.2%) in the high-risk category. CONCLUSIONS: The validated risk index can help identify asymptomatic patients who are at greatest risk for 30-day stroke, MI, and death after CEA, thereby aiding patient selection.

In-hospital and postdischarge venous thromboembolism after vascular surgery.

OBJECTIVE: Recent single-center reports demonstrate a high (up to 10%) incidence of postoperative venous thromboembolism (VTE) after major vascular surgery. Moreover, vascular patients rarely receive prolonged prophylaxis despite evidence that it reduces thromboembolic events after discharge. This study used a national, prospective, multicenter database to define the incidence of overall and postdischarge VTE after major vascular operations and assess risk factors associated with VTE development. METHODS: Patients with VTE who underwent elective vascular procedures (n = 45,548) were identified from the 2007-2009 National Surgical Quality Improvement Program (NSQIP) database. The vascular procedures included carotid endarterectomy (CEA; n = 20,785), open thoracoabdominal aortic aneurysm (TAAA) repair (n = 361), thoracic endovascular aortic repair (TEVAR; n = 732), open abdominal aortic (OAA) surgery (n = 6195), endovascular aneurysm repair (EVAR; n = 7361), and infrainguinal bypass graft (BPG; n = 10,114). Univariable and multivariable analyses were performed to ascertain risk factors associated with VTE. RESULTS: VTE was diagnosed in 187 patients (1.3 %) who underwent aortic surgery, with TAAA repair having the highest rate of VTE (4.2%), followed by TEVAR (2.2%), OAA surgery (1.7%), and EVAR (0.7%). In this subgroup, pulmonary embolisms (PE) were diagnosed in 52 (0.4%) and deep venous thrombosis (DVT) in 144 (1%). VTE rates were 1.0% and 0.2% for patients who underwent a BPG or CEA, respectively. Forty-one percent of all VTEs were diagnosed after discharge. The median (interquartile range) number of days from surgery to PE and DVT were 10 (5-15) and 10 (4-18), respectively. On multivariable analyses, type of surgical procedure, totally dependent functional status, disseminated cancer, postoperative organ space infection, postoperative cerebrovascular accident, failure to wean from ventilator ≤48 hours, and return to the operating room were significantly associated with development of VTE. In those experiencing a DVT or PE, overall mortality increased from 1.5% to 6.2% and from 1.5% to 5.7% respectively (P < .05 for both). CONCLUSIONS: Postoperative VTE is associated with the type of vascular procedure and is highest after operations in the chest and abdomen/pelvis. About 40% of VTE events in elective vascular surgery patients were diagnosed after discharge, and the presence of VTE was associated with a quadrupled mortality rate. Future studies should evaluate the benefit of DVT screening and postdischarge VTE prophylaxis in high-risk patients.

Development of a risk index for prediction of mortality after open aortic aneurysm repair.

OBJECTIVE: Open infrarenal abdominal aortic aneurysm (oAAA) repair is associated with significant morbidity and mortality. Although there has been a shift toward endovascular repair, many patients continue to undergo an open repair due to anatomic considerations. Tools currently existing for estimation of periprocedural risk in patients undergoing open aortic surgery have certain limitations. The objective of this study was to develop a risk index to estimate the risk of 30-day perioperative mortality after elective oAAA repair. METHODS: Patients who underwent elective oAAA repair (n = 2845) were identified from the American College of Surgeons' 2007 to 2009 National Surgical Quality Improvement Program (NSQIP), a prospective database maintained at >250 centers. Univariable and multivariable analyses were performed to evaluate risk factors associated with 30-day mortality after oAAA repair and a risk index was developed. RESULTS: The 30-day mortality after oAAA repair was 3.3%. Multivariable analysis identified six preoperative predictors of mortality, and a risk index was created by assigning weighted points to each predictor using the ß-coefficients from the regression analysis. The predictors included dyspnea (at rest: 8 points; on moderate exertion: 2 points; none: 0 points), history of peripheral arterial disease requiring revascularization or amputation (3 points), age >65 years (3 points), preoperative creatinine >1.5 mg/dL (2 points), female gender (2 points), and platelets <150,000/mm(3) or >350,000/mm(3) (2 points). Patients were classified as low (<7%), intermediate (7%-15%), and high (>15%) risk for 30-day mortality based on a total point score of <8, 8 to 11, and >11, respectively. There were 2508 patients (88.2%) patients in the low-risk category, 278 (9.8%) in the intermediate-risk category, and 59 (2.1%) in the high-risk category. CONCLUSIONS: This risk index has excellent predictive ability for mortality after oAAA repair and awaits validation in subsequent studies. It is anticipated to aid patients and surgeons in informed patient consent, preoperative risk assessment, and optimization.

Development and validation of a risk calculator for prediction of cardiac risk after surgery.

BACKGROUND: Perioperative myocardial infarction or cardiac arrest is associated with significant morbidity and mortality. The Revised Cardiac Risk Index is currently the most commonly used cardiac risk stratification tool; however, it has several limitations, one of which is its relatively low discriminative ability. The objective of the present study was to develop and validate a predictive cardiac risk calculator. METHODS AND RESULTS: Patients who underwent surgery were identified from the American College of Surgeons' 2007 National Surgical Quality Improvement Program database, a multicenter (>250 hospitals) prospective database. Of the 211 410 patients, 1371 (0.65%) developed perioperative myocardial infarction or cardiac arrest. On multivariate logistic regression analysis, 5 predictors of perioperative myocardial infarction or cardiac arrest were identified: type of surgery, dependent functional status, abnormal creatinine, American Society of Anesthesiologists' class, and increasing age. The risk model based on the 2007 data set was subsequently validated on the 2008 data set (n=257 385). The model performance was very similar between the 2007 and 2008 data sets, with C statistics (also known as area under the receiver operating characteristic curve) of 0.884 and 0.874, respectively. Application of the Revised Cardiac Risk Index to the 2008 National Surgical Quality Improvement Program data set yielded a relatively lower C statistic (0.747). The risk model was used to develop an interactive risk calculator. CONCLUSIONS: The cardiac risk calculator provides a risk estimate of perioperative myocardial infarction or cardiac arrest and is anticipated to simplify the informed consent process. Its predictive performance surpasses that of the Revised Cardiac Risk Index.

Development and validation of a risk calculator for prediction of mortality after infrainguinal bypass surgery.

OBJECTIVE: For peripheral arterial disease, infrainguinal bypass grafting (BPG) carries a higher perioperative risk compared with peripheral endovascular procedures. The choice between the open and endovascular therapies is to an extent dependent on the expected periprocedural risk associated with each. Tools for estimating the periprocedural risk in patients undergoing BPG have not been reported in the literature. The objective of this study was to develop and validate a calculator to estimate the risk of perioperative mortality ≤30 days of elective BPG. METHODS: We identified 9556 patients (63.9% men) who underwent elective BPG from the 2007 to 2009 National Surgical Quality Improvement Program data sets. Multivariable logistic regression analysis was performed to identify risk factors associated with 30-day perioperative mortality. Bootstrapping was used for internal validation. The risk factors were subsequently used to develop a risk calculator. RESULTS: Patients had a median age of 68 years. The 30-day mortality rate was 1.8% (n = 170). Multivariable logistic regression analysis identified seven preoperative predictors of 30-day mortality: increasing age, systemic inflammatory response syndrome, chronic corticosteroid use, chronic obstructive pulmonary disease, dependent functional status, dialysis dependence, and lower extremity rest pain. Bootstrapping was used for internal validation. The model demonstrated excellent discrimination (C statistic, 0.81; bias-corrected C statistic, 0.81) and calibration. The validated risk model was used to develop an interactive risk calculator using the logistic regression equation. CONCLUSIONS: The validated risk calculator has excellent predictive ability for 30-day mortality in a patient after an elective BPG. It is anticipated to aid in surgical decision making, informed patient consent, preoperative optimization, and consequently, risk reduction.

Predictive factors for mortality after open repair of paravisceral abdominal aortic aneurysm.

OBJECTIVE: The use of fenestrated and branched stent graft technology for paravisceral abdominal aortic aneurysms (PAAA) is on the rise; however, its application is limited in the United States to only a few selected centers. Most PAAAs are currently repaired using an open approach. The objective of this study was to determine which patients are at highest risk with open PAAA repair and might benefit most from endovascular repair using fenestrated or branched stent grafts. METHODS: This was a retrospective cohort study using data from American College of Surgeons National Surgical Quality Improvement Program (NSQIP) hospitals. We identified 598 patients (27.5% women) who underwent elective open PAAA repair from the 2007 to 2009 NSQIP, a prospective database maintained at >250 centers. The main outcome measure was 30-day postoperative mortality. RESULTS: The median patient age was 73 years. The 30-day major morbidity rate was 30.1%, and the mortality rate was 4.5%. Major complications included reintubation (10.0%), sepsis (10.7%), return to operating room (9.2%), new dialysis requirement (5.9%), cardiac arrest or myocardial infarction (4.5%), and stroke (1.2%). Multivariate analyses identified four predictors of postoperative mortality after open PAAA repair: peripheral arterial disease (PAD) requiring revascularization or amputation, chronic obstructive pulmonary disease (COPD), anesthesia time, and female sex. PAD and COPD were present in only 5.2% and 20.4% of patients but were associated with a 16.1% and 9.0% mortality rate, respectively. The mortality rate in women was 7.3% vs 3.5% for men (P = .045). CONCLUSIONS: PAD, COPD, and female sex are major risk factors for postoperative mortality after open PAAA repair. Fenestrated or branched stent graft repair may be a more valuable alternative to open repair for patients with one or more of these characteristics who have suitable access vessels.

A population-based study of risk factors for stroke after carotid endarterectomy using the ACS NSQIP database.

BACKGROUND: The benefit of carotid endarterectomy (CEA) is heavily influenced by the risk of perioperative stroke. Our objective was to use the American College of Surgeons' 2007 and 2008 National Surgical Quality Improvement Program (NSQIP) database to assess the postoperative stroke and death rate after CEA among the more than 180 NSQIP participating hospitals, and to identify the preoperative risk factors. MATERIALS AND METHODS: Univariate analysis included 56 preoperative variables. Outcomes were studied for 30 d. Multivariate logistic regression was used for assessment of risk factors. RESULTS: Of 13,316 patients, 7503 (56.5%) were asymptomatic, while 5770 (43.5%) were symptomatic. Combined stroke or death was seen in 262 patients (2.0%). Postoperative stroke occurred in 186 patients (1.4%). One hundred patients (0.8%) died within 30 d. In asymptomatic and symptomatic patients, stroke or death was seen in 1.3% and 2.9% of patients; stroke in 0.9% and 2% of patients; and death in 0.5% and 1.1% of patients, respectively (all P < 0.001). On multivariate analysis for symptomatic patients, dialysis dependence, chronic open wound, impaired sensorium, and dependent functional status were risk factors for stroke or death (all P < 0.05). Among asymptomatic patients, acute renal failure, corticosteroid use, COPD, paraplegia, and dependent functional status were risk factors for stroke or death (all P < 0.05). CONCLUSIONS: This prospective database confirms that CEA is currently performed with low peri-procedural stroke rate in participating ACS NSQIP hospitals and provides a contemporary framework for comparison of other treatment modalities to CEA. Identification of the above risk factors may help with risk stratification and patient counseling for CEA.

Determinants of outcomes in pancreatic surgery and use of hospital resources.

BACKGROUND AND OBJECTIVES: Outcomes for patients undergoing major pancreatic surgery have improved, but a subset of patients that significantly utilize more resources exists. Variables that can lead to an increase in resource utilization in patients undergoing pancreatic surgery were identified. METHODS: Patients undergoing pancreatic surgery for neoplasms were identified from the NSQIP database (2006-2008). Indices associated with increased resource utilization that we included were operative time (OT), length of stay (LOS), intraoperative RBC transfusion, return to operating room, and occurrence of postoperative complications. Analysis of covariance and multivariable logistic regression were performed. RESULTS: The 4,306 included patients had a median age of 66 years and 50.3% were males. The 30-day morbidity and mortality were 29.3% and 3.2%, respectively. Median OT was 362 min and median LOS was 10 days. Malignancy, neoadjuvant radiation, and medical co-morbidities were associated with increased OT (P < 0.0001 for all). Declining preoperative functional status was the most important predictor of LOS (P < 0.0001). Age, male gender, hypertension, severe COPD, and higher BMI were significantly associated with postoperative complications (P < 0.050 for all). CONCLUSIONS: Morbidity after pancreatic surgery remains high. Age, obesity, performance status, medical co-morbidities, and neoadjuvant radiation affect outcomes and may lead to increased use of hospital resources.

Determinants of resource utilization and outcomes in laparoscopic Roux-en-Y gastric bypass: a multicenter analysis of 14,251 patients.

BACKGROUND: Outcomes for patients who undergo laparoscopic Roux-en-Y gastric bypass (LRYGB) surgery have improved, but a subset of patients who significantly utilize more resources exists. We identified preoperative variables that increase resource utilization in patients who undergo LRYGB. METHODS: Patients who underwent LRYGB in 2007 and 2008 were identified from the NSQIP database. Variables that indicated resource utilization were operative time (OT), length of stay (LOS), and occurrence of postoperative complications. Analyses were performed by using multivariate analysis of variance and logistic regression. RESULTS: Of 14,251 patients with a mean age of 44.6 (± 11.1) years, 19.4% were men. The national 30-day morbidity and mortality were 4.5% and 0.17%, respectively. The median OT was 128 min (interquartile range (IQR), 100-167), and the median LOS was 2 days (IQR, 2-3). Bleeding disorder, male gender, African American race, increasing weight, and age were significantly associated with increased OT (p < 0.05 for all). Severe chronic obstructive pulmonary disease, bleeding disorder, increasing age, and anesthesia time were associated with increased length of stay (p < 0.05). Preoperative dialysis dependence (odds ratio (OR), 8.5; 95% confidence interval (CI), 2.3-32.3) and dyspnea at rest (OR, 3.3; 95% CI, 1.7-6.3) were the greatest predictors of postoperative complications. Emergency case, bleeding disorder, prior percutaneous coronary intervention, and increasing operative time also were significantly associated with increased postoperative complications on multivariate logistic regression analysis (p < 0.05 for all). CONCLUSIONS: Age, sex, race, obesity, and some medical comorbidities affect outcomes and increase resource utilization. Optimization of modifiable factors and careful patient selection are needed to facilitate further improvement in outcomes and resource utilization.