Association Between Coronavirus Disease 2019 Vaccination and Mortality After Major Operations.

OBJECTIVE: The objective of this study was to compare postoperative 90-day mortality between (1) fully vaccinated patients with COVID-19-positive and negative diagnosis, and (2) vaccinated and unvaccinated patients with COVID-19 positive diagnosis. BACKGROUND: Societal guidelines recommend postponing elective operations for at least 7 weeks in unvaccinated patients with preoperative coronavirus disease 2019 (COVID-19) infection. The role of vaccination in this infection-operation time risk is unclear. METHODS: We conducted a national US multicenter retrospective, matched cohort study spanning July 2021 to October 2022. Participants were included if they underwent a high-risk general, vascular, orthopedic, neurosurgery, or genitourinary surgery. All-cause mortality occurring within 90 days of the index operation was the primary outcome. Inverse probability treatment weighted propensity scores were used to adjust logistic regression models examining the independent and interactive associations between mortality, exposure status, and infection proximity. RESULTS: Of 3401 fully vaccinated patients in the 8-week preoperative period, 437 (12.9%) were COVID-19-positive. Unadjusted mortality rates were not significantly different between vaccinated patients with COVID-19 (22, 5.0%) and vaccinated patients without COVID-19 (99, 3.3%; P = 0.07). After inverse probability treatment weighted adjustment, mortality risk was not significantly different between vaccinated COVID-19-positive patients compared to vaccinated patients without COVID-19 (adjusted odds ratio = 1.38, 95% CI: 0.70, 2.72). The proximity of COVID-19 diagnosis to the index operation did not confer added mortality risk in either comparison cohort. CONCLUSIONS: Contrary to risks observed among unvaccinated patients, postoperative mortality does not differ between patients with and without COVID-19 when vaccinated against the severe acute respiratory syndrome coronavirus 2 virus and receiving a high-risk operation within 8 weeks of the diagnosis, regardless of operation timing relative to diagnosis.

In-hospital Mortality Risk after Endovascular and Open Aortic Aneurysm Repairs for Ruptured Abdominal Aortic Aneurysms.

INTRODUCTION: Observational studies demonstrate reduced mortality after endovascular (EVAR) compared to open aneurysm repair (OAR) for ruptured abdominal aortic aneurysms (rAAA). We sought to determine national trends in repair type and in-hospital mortality rates for rAAA. METHODS: We analyzed patients with rAAA managed with OAR or EVAR from 2002 to 2020 in the National Inpatient Sample and evaluated annual trends in volume and in-hospital mortality by repair type. Multilevel mixed effects logistic regression model was fit for patient and system-level risk adjustment. We assessed interactions between time, sex, and Elixhauser index with repair type. RESULTS: We examined 13,376 patients with rAAA. 8,357 (62.5%) underwent OAR. Patients receiving EVAR were slightly older (73.7 vs 72.5 years; p<0.001) with slightly higher mean Elixhauser index (4.0 vs 3.8; p<0.001). Unadjusted in-hospital mortality was 37.4% vs. 22.4% for OAR and EVAR respectively. EVAR offered a risk-adjusted survival advantage (OR: 0.39, 95% CI: 0.32, 0.46). There was a statistically significant reduction of in-hospital mortality over time in the EVAR group (interaction OR = 0.96, 95% CI: 0.95, 0.98). The interaction between Elixhauser index and repair was not statistically significant (interaction OR: 0.95, 95% CI: 0.87, 1.05). CONCLUSIONS: Survival rates for OAR and EVAR improved over time. EVAR persistently provided a substantial survival advantage over OAR in patients with rAAA over the past two decades.

Association Between Pack-Years and Smoking Cessation on Outcomes After Vascular Interventions.

INTRODUCTION: The influence of pack-year history and smoking cessation timing on postoperative morbidity and mortality in a highly comorbid cohort is uncertain. We examined whether the association between smoking and adverse postoperative events is modified by pack-year history and smoking cessation timing. METHODS: We collected single-institution, retrospective data from consecutive patients undergoing open operations for carotid, aortic, and infrainguinal arterial disease. Active smoking was defined as smoking on the day of the index surgical intervention. Duration of smoking cessation was calculated as the time between smoking cessation and index surgery. The primary outcome was a composite of 30-day mortality and morbidity. Logistic and time-to-event Cox regressions estimated associations with interactions between cessation duration and pack-year history for nonactive smokers. RESULTS: Between 2010 and 2019, 1087 patients underwent 1640 high-risk vascular interventions. Median pack-year history was 40.0 pack-years (interquartile range [IQR]: 20.0-60.0) among nonactive smokers and 46.0 pack-years (IQR: 31.0-61.0) among active smokers (P < 0.001). The median smoking cessation time was 15.5 y (IQR: 4.4-30.9). Smoking status did not independently predict an increased risk of postoperative mortality or morbidity (odds ratio [OR] = 0.99, P = 0.96). Among nonactive smokers, neither smoking cessation duration (OR = 0.99, P = 0.16) nor pack-year history (OR = 1.00, P = 0.88) were significantly associated with adverse events (interaction P = 0.11). CONCLUSIONS: After high-risk vascular interventions in a single institution, active smoking, cessation period, and pack-year history are not associated with an increased risk of postoperative morbidity or mortality-highlighting the benefit of cessation as independent of frequency or intensity.

Timing of a Major Operative Intervention After a Positive COVID-19 Test Affects Postoperative Mortality: Results From a Nationwide, Procedure-matched Analysis.

BACKGROUND: Studies indicate that coronavirus disease 2019 (COVID-19) infection before or soon after operations increases mortality, but they do not comment on the appropriate timing for interventions after diagnosis. OBJECTIVE: We sought to determine what the safest time would be for COVID-19 diagnosed patients to undergo major operative interventions. METHODS: High-risk operations, between January 2020 and May 2021, were identified from the Veterans Affairs COVID-19 Shared Data Resource. Current Procedural Terminology (CPT) codes were used to exact match COVID-19 positive cases (n=938) to negative controls (n=7235). Time effects were calculated as a continuous variable and then grouped into 2-week intervals. The primary outcome was 90-day, all-cause postoperative mortality. RESULTS: Ninety-day mortality in cases and controls was similar when the operation was performed within 9 weeks or longer after a positive test; but significantly higher in cases versus controls when the operation was performed within 7 to 8 weeks (12.3% vs 4.9%), 5 to 6 weeks (10.3% vs 3.3%), 3 to 4 weeks (19.6% vs 6.7%), and 1 to 2 weeks (24.7% vs 7.4%) from diagnosis. Among patients who underwent surgery within 8 weeks from diagnosis, 90-day mortality was 16.6% for cases versus 5.8% for the controls ( P <0.001). In this cohort, we assessed interaction between case status and any symptom ( P =0.93), and case status and either respiratory symptoms or fever ( P =0.29), neither of which were significant statistically. CONCLUSIONS: Patients undergoing major operations within 8 weeks after a positive test have substantially higher postoperative 90-day mortality than CPT-matched controls without a COVID-19 diagnosis, regardless of presenting symptoms.

Racial and ethnic disparities in abdominal aortic aneurysm evaluation and treatment rates in Texas.

BACKGROUND: Screening identifies intact abdominal aortic aneurysms (iAAAs) before progression to ruptured AAAs (rAAAs). However, screening efforts have been limited by the low overall diagnostic yield and unequal screening among minority populations. The goal of the present study was to identify equitable AAA screening strategies for both majority and minority populations. METHODS: We performed epidemiologic and geospatial analyses of inpatient and outpatient procedures for iAAAs and rAAAs at Texas hospitals from 2006 through 2014 at all nonfederal hospitals and clinics in Texas. The data were aggregated by area (metropolitan statistical area vs rural region) and then supplemented by six additional data sources to estimate the AAA repair incidence rates, rates of AAA-related clinic and ultrasound visits, travel distance to providers, and the location and number of unrecognized AAAs. RESULTS: Most AAA repairs had occurred among men aged 65 to 84 years and categorized as White in large metropolitan areas. The area procedure rates for rAAAs and iAAAs were strongly correlated (R2 = 0.47). Two other variables-the proportions of persons categorized as White and those aged ≥65 years in a region-identified subgroups within the majority population with a high risk of iAAAs (R2 = 0.46). Lower rates of clinic visits and AAA ultrasound scans were seen among persons categorized as Black. Several areas with disproportionately higher rAAA/iAAA repair ratios were found, mainly affecting persons categorized as Black. CONCLUSIONS: Multiple focused AAA screening strategies could be required to address the disproportionately lower AAA identification among persons categorized as Black.

Factors associated with preference of choice of aortic aneurysm repair in the PReference for Open Versus Endovascular repair of AAA (PROVE-AAA) study.

OBJECTIVE: Patients can choose between open repair and endovascular repair (EVAR) of abdominal aortic aneurysm (AAA). However, the factors associated with patient preference for one repair type over another are not well-characterized. Here we assess the factors associated with preference of choice for open or endovascular AAA repair among veterans exposed to a decision aid to help with choosing surgical treatment. METHODS: Across 12 Veterans Affairs hospitals, veterans received a decision aid covering domains including patient information sources and understanding preference. Veterans were then given a series of surveys at different timepoints examining their preferences for open versus endovascular AAA repair. Questions from the preference survey were used in analyses of patient preference. Results were analyzed using χ2 tests. A logistic regression analysis was performed to assess factors associated with preference for open repair or preference for EVAR. RESULTS: A total of 126 veterans received a decision aid informing them of their treatment choices, after which 121 completed all preference survey questions; five veterans completed only part of the instruments. Overall, veterans who preferred open repair were typically younger (70 years vs 73 years; P = .02), with similar rates of common comorbidities (coronary disease 16% vs 28%; P = .21), and similar aneurysms compared with those who preferred EVAR (6.0 cm vs 5.7 cm; P = .50). Veterans in both preference categories (28% of veterans preferring EVAR, 48% of veterans preferring open repair) reported taking their doctor's advice as the top box response for the single most important factor influencing their decision. When comparing the tradeoff between less invasive surgery and higher risk of long-term complications, more than one-half of veterans preferring EVAR reported invasiveness as more important compared with approximately 1 in 10 of those preferring open repair (53% vs 12%; P < .001). Shorter recovery was an important factor for the EVAR group (74%) and not important in the open repair group (76%) (P = .5). In multivariable analyses, valuing a short hospital stay (odds ratio, 12.4; 95% confidence interval, 1.13-135.70) and valuing a shorter recovery (odds ratio, 15.72; 95% confidence interval, 1.03-240.20) were associated with a greater odds of preference for EVAR, whereas finding these characteristics not important was associated with a greater odds of preference for open repair. CONCLUSIONS: When faced with the decision of open repair versus EVAR, veterans who valued a shorter hospital stay and a shorter recovery were more likely to prefer EVAR, whereas those more concerned about long-term complications preferred an open repair. Veterans typically value the advice of their surgeon over their own beliefs and preferences. These findings need to be considered by surgeons as they guide their patients to a shared decision.

Treatment of Early Deep Wound Infections after Arterial Reconstructions: A Meta-Analysis and Survey.

BACKGROUND: Peripheral vascular graft infections, a serious concern after open lower extremity interventions, are treated using multiple strategies. Yet, there is no consensus on the optimal treatment. This study summarizes the literature and compares aggregate effect sizes between graft preservation with antibiotic beads and total graft excision. METHODS: Manuscripts published between 1972 and 2019 were systematically queried using Ovid Medline and PubMed. Studies were included if they described early (≤4 months of the index procedure) infection-related outcomes after extracavitary and infrainguinal arterial graft infections that were managed with antibiotic-loaded beads or total excisions. Outcomes assessed included the prevalence of graft preservation failure, reinfection, and major amputation. To examine current preferences on this subject, a voluntary, anonymous survey was administered to practicing members of the Society for Clinical Vascular Surgery. RESULTS: Six graft preservation studies (n = 147 patients) were included in the meta-analysis, based on PRISMA guidelines. The meta-analytic pooled proportion of patients with: (1) graft preservation failure was 0.09 (95% CI: 0.00, 0.46, I2 = 88.8%), (2) reinfection was 0.04 (95% CI: 0.00, 0.18, I2 = 79.7%), and (3) major amputation was 0.00 (95% CI: 0.00, 0.04, I2 = 0%). Five studies addressing total excisions were identified via the systematic review however, their combined sample size (n = 28 patients) impeded use of a meta-analysis. Ninety (19%) licensed surgeons participated in the survey. In a hemodynamically stable, nonseptic patient, 67% (60) of respondents routinely excise the graft, while 31% (28) prefer preservation. CONCLUSIONS: Study design and patient characteristic-related heterogeneity limited our ability to generate robust, clinical evidence-level outcome estimates. A prospective study is necessary to definitively establish the efficacy of antibiotic beads in the treatment and preservation of vascular graft infections.

Outcomes after Endovascular Stent Placement for Long-Segment Superficial Femoral Artery Lesions.

BACKGROUND: Endovascular intervention is commonly pursued as first-line management of symptomatic, long-segment superficial femoral artery (SFA) disease. The relative effectiveness and comparative long-term outcomes among bare metal stents (BMS), covered stents (CS), and drug-eluting stents (DES) for long-segment SFA lesions remain uncertain. METHODS: A retrospective cohort study identified patients with symptomatic SFA lesions measuring at least 15 cm in length who successfully received an endovascular stent (BMS, CS, or DES). The outcomes were patency, patient presentation upon stent occlusion, amputation-free survival (AFS), and all-cause mortality. Proportional hazards regressions and a multinomial logistic regression model were used to control for significant confounders. RESULTS: A total of 226 procedures were analyzed (BMS: 95 [42%]; CS: 74 [33%]; DES: 57 [25%]). There were no significant differences among the 3 stent types with respect to age, prevalence of either diabetes or end-stage renal disease, or smoking history. The median length of the SFA lesion varied across the cohorts (BMS: 28 cm [interquartile range, IQR 20-30]; CS: 26 cm [IQR 20-30]; DES: 20 cm [IQR 16-25]; P = 0.002). The unadjusted primary patency of BMS at 12, 24, and 48 month following index stent placement was 57%, 47%, and 44%, respectively. This is compared to 62%, 49%, and 42% for CS, and 81%, 66%, and 53% for DES, respectively (log-rank P = 0.044). In adjusted models, however, there were no significant differences in primary patency among the stent types. Compared to CS however, DES was associated with improved primary-assisted patency (hazard ratio [HR] for patency loss: 0.35, P = 0.008) and secondary patency (HR: 0.32, P = 0.011). Across the entire follow-up period, stent occlusions occurred in 38 (40%) BMS cases, 42 (57%) CS, and 11 (19%) DES (P < 0.001). Of these, acute limb ischemia (ALI) occurred in 2 (5%) BMS cases, 14 (33%) CS, and 1 (9%) DES (P = 0.010). After adjustment, the relative risk of presenting with ALI as opposed to claudication was 27 times greater among patients re-presenting with occluded CS compared to BMS (P = 0.020). There were no significant differences in AFS or all-cause mortality across the 3 cohorts. CONCLUSIONS: For long-segment SFA lesions, DES is associated with improved primary-assisted and secondary patency over long-term follow-up. In the event of stent occlusion, CS is associated with an increased risk of ALI.

Long-term outcomes of lower extremity graft preservation using antibiotic beads in patients with early deep wound infections after major arterial reconstructions.

OBJECTIVE: Bypass graft preservation with wound sterilization using serial antibiotic bead exchange has been described in patients presenting with deep wound infections after extremity bypass. The long-term benefits of this approach remain poorly understood. We examined whether graft preservation and wound sterilization with antibiotic beads affect amputation rates and patient survival. METHODS: Patients who underwent operations for aortoiliac or infrainguinal aneurysmal or occlusive arterial disease were retrospectively analyzed. The Infection group included those with patent vascular grafts who developed Szilagyi class II or III deep wound infections within 90 days of index reconstruction and had no evidence of anastomotic or arterial bleeding. All patients in the infection group were managed with graft preservation using serial antibiotic bead exchange every 3 to 5 days until wound cultures became negative. This group was compared with a contemporary group of controls who underwent similar interventions but did not develop wound infections postoperatively. The primary outcome was amputation-free survival, defined as survival without major amputation. Secondary outcomes included major amputations and the occurrence of anastomotic pseudoaneurysms necessitating repair. Inverse propensity score weighting was used for risk adjustment between the groups. RESULTS: Over an 8-year period, we treated 701 patients (infection, 68; controls, 633). Compared with controls, patients in the infection group had a higher body mass index (mean, 28.5 vs 26.3, P = .002) and more prosthetic conduits placed during the index reconstruction. Amputation-free survival for the infection vs the control group was 78 vs 76% at 2 years, 61 vs 66% at 4 years, and 51 vs 57% at 6 years postoperatively (log-rank test, P = .516). Freedom from major amputation for the infection vs the control group was 82 vs 86% at 2 years, 80 vs 82% at 4 years, and 80 vs 76% at 6 years postoperatively (log-rank test, P = .568). In the risk-adjusted model, the presence of treated infection did not affect amputation-free survival (hazard ratio, 0.82; P = .440) or major amputation (hazard ratio, 1.02; P = .949). Anastomotic pseudoaneurysms occurred only in the Infection group (4.4%; P = .001), and were treated with interposition grafts without complications. CONCLUSIONS: Bypass graft preservation with wound sterilization using serial antibiotic bead exchange is associated with excellent limb salvage and survival rates, similar to those of noninfected wounds. With the use of this preservation strategy, close follow-up for timely detection of anastomotic pseudoaneurysms is recommended.

Wound Complications and Reoperations after Transtibial Amputation of the Leg.

BACKGROUND: Transtibial amputations (TTAs) of the leg have been associated with high rates of wound complications. We assessed outcomes of TTAs to determine if bundled interventions implemented at our hospital had an impact on lowering wound complications, including surgical site infections. METHODS: We assessed the impact of a surgical site infection prevention bundle (negative-pressure wound therapy, minimizing the use of staples, and a decontamination protocol for methicillin-resistant Staphylococcus aureus) on 90-day wound complications. The year of implementation of the prevention bundle was excluded, and the pre-eras and posteras were defined as the four-year period before and after implementation. The study sample consisted of a single-center cohort, with TTA cases identified using operating room scheduling software. RESULTS: A total of 182 TTAs were performed: 110 in the pre-era and 72 in the postera. The wound complication rate decreased from 22 to 17% despite fewer two-stage operations, less imaging to identify peripheral artery disease, and an increased proportion of patients with end-stage renal disease. Wound complications and revision to a higher level of amputation were more associated with indication (especially no-option peripheral artery disease with ischemic rest pains) than with any particular aspect of surgical technique. The use of drains was associated with reoperations but not higher level revision. CONCLUSIONS: Higher rates of wound complications and revision to a higher level of amputations should be expected among patients with no-option peripheral artery disease with ischemic rest pains undergoing TTAs. Drains should be avoided.

Effect of Postoperative Permissive Anemia and Cardiovascular Risk Status on Outcomes After Major General and Vascular Surgery Operative Interventions.

OBJECTIVES: To determine the effect of postoperative permissive anemia and high cardiovascular risk on postoperative outcomes. METHODS: The Veterans Affairs Surgical Quality Improvement Program and Corporate Data Warehouse databases were queried for patients who underwent major vascular or general surgery operations. The status of cardiovascular risk was assessed by calculating the Revised Cardiac Risk Index. Primary endpoint was a composite of mortality, myocardial infarction, acute renal failure, coronary revascularization, or stroke within 90 days postoperatively. RESULTS: We analyzed 142,510 procedures performed from 2000 to 2015. Postoperative anemia was the strongest independent predictor of the primary endpoint whose odds increased by 43% for every g/dL drop in postoperative nadir Hb [95% confidence interval (95% CI): 41-45]. Cardiac risk status as described by the RCRI also independently predicted the primary endpoint, with an additive effect particularly evident at postoperative nadir Hb values below 10 gm/dL. Postoperative anemia, after age, was the second strongest independent predictor of long-term (12 years) mortality (hazard ratio: 1.18, 95% CI: 1.17-1.19). CONCLUSION: Postoperative anemia is strongly associated with postoperative ischemic events, 90-day mortality, and long-term mortality. Restrictive transfusion should be used cautiously after major general and vascular operations, particularly in patients at a high cardiovascular risk.

A Statistical Model-driven Surgical Case Scheduling System Improves Multiple Measures of Operative Suite Efficiency: Findings From a Single-center, Randomized Controlled Trial.

OBJECTIVE: We sought to determine whether a data-driven scheduling approach improves Operative Suite (OS) efficiency. BACKGROUND: Although efficient use of the OS is a critical determinant of access to health care services, OS scheduling methodologies are simplistic and do not account for all the available characteristics of individual surgical cases. METHODS: We randomly scheduled cases in a single OS by predicting their length using either the historical mean (HM) duration of the most recent 4 years; or a regression modeling (RM) system that accounted for operative and patient characteristics. The primary endpoint was the imprecision in prediction of the end of the operative day. Secondary endpoints included measures of OS efficiency; personnel burnout captured by the Maslach Burnout Inventory; and a composite endpoint of 30-day mortality, myocardial infarction, wound infection, bleeding, amputation, or reoperation. RESULTS: Two hundred and seven operative days were allocated to scheduling with either the RM or the HM methodology. Mean imprecision in predicting the end of the operative day was higher with the HM approach (30.8 vs 7.2 minutes, P = 0.024). RM was associated with higher throughput (379 vs 356 cases scheduled over the course of the study, P = 0.04). The composite rate of adverse 30-day events was similar (2.2% vs 3.2%, P = 0.44). The mean depersonalization score was higher (3.2 vs 2.0, P = 0.044), and mean personal accomplishment score was lower during HM weeks (37.5 vs 40.5, P = 0.028). CONCLUSIONS: Compared to the HM scheduling approach, the proposed data-driven RM scheduling methodology improves multiple measures of OS efficiency and OS personnel satisfaction without adversely affecting clinical outcomes.

Arteriovenous fistula maturation rate is not affected by ipsilateral tunneled dialysis catheter.

OBJECTIVE: The effect that ipsilateral tunneled dialysis catheters (TDC) have on arteriovenous fistula (AVF) maturation is unclear. We sought to define this association by comparing AVF maturation rates in patients with contralateral TDC with those with ipsilateral TDC. METHODS: A review of a prospectively maintained database including all AVF creation procedures between 2009 and 2016 was performed. All patients with a TDC in place at the time of AVF creation were included in this study. Clinical and functional maturation rates were compared in patients with contralateral vs ipsilateral dialysis catheters. Categorical variables were analyzed by a two-tailed Fisher's exact test. A P value of less than .05 was considered statistically significant. RESULTS: There were 187 patients who underwent fistula creation with a TDC in place during the study period. Of those, 137 patients had a contralateral TDC and 50 had an ipsilateral TDC. A greater proportion of contralateral patients were first-time dialysis access patients at the time of index AVF creation (67% vs 48%; P = .03). There was no difference in clinical (contralateral 73% vs ipsilateral 78%; P = .57) and functional (contralateral 64% vs ipsilateral 74%) maturation rates between the two groups. The rate of TDC removal after AVF maturation was also not different (contralateral 64% vs ipsilateral 72%; P = .30). There was also no statistical difference in the rates of thrombosis at less than 30 days, outflow stenosis, central stenosis, and steal syndrome. CONCLUSIONS: There was no association between TDC sidedness and AVF maturation or early failure in our cohort. Planning for AVF creation should not be influenced by attempts to avoid an ipsilateral TDC.

Ischemia-induced lower extremity neurologic impairment after fenestrated endovascular aneurysm repair.

OBJECTIVE: Placement of large sheaths in the iliac system during fenestrated endovascular aneurysm repair (FEVAR) leads to lower extremity (LE) ischemia that can be associated with serious neurologic complications. We sought to determine the effect of LE ischemic time on neurologic impairment after FEVAR. METHODS: Consecutive patients who underwent FEVAR at a single institution were analyzed. LE ischemic time was calculated from the time of large sheath (≥18F) insertion to the time of sheath removal from the iliac arteries that led to continuous LE ischemia. The primary outcome was neurologic impairment defined as any new sensory or motor deficit in either LE. Outcomes were analyzed using descriptive statistics and modeled with logistic regression with interaction terms. Each individual LE was used as a unit of analysis. RESULTS: We examined 101 patients (202 lower extremities) who underwent FEVAR over a 5-year period. The median LE ischemic time was 2.75 hours (range, 0.8-5.2 hours). Neurologic impairment developed in 18 extremities (9%). Of those, 12 (67%) developed mild sensory loss, 6 (33%) complete sensory loss, 4 (22%) loss of proprioception, and 2 (11%) motor dysfunction. Sensory deficit was permanent in four limbs (2%) and motor dysfunction in one limb (0.5%). In all other cases, the neurologic examination returned to baseline by postoperative day 15. Duration of LE ischemic time (odds ratio, 6.3; 95% confidence interval, 3.1-12.4; P < .001) and common iliac artery (CIA) stenosis to a lumen of 8 mm or less (odds ratio, 2.7; 95% confidence interval, 1.5-7.3; P = .002) were independent predictors for the development of neurologic impairment. An interaction term between LE ischemic time and CIA stenosis was statistically significant (P = .042), indicating that the presence of CIA stenosis modifies the effect of LE ischemic time. In those with CIA stenosis to a lumen of 8 mm or less, the risk of neurologic impairment increased rapidly after 2.5 hours of LE ischemia, and became nearly certain after 4 hours of ischemic time. By contrast, patients without CIA stenosis tolerated longer ischemic times and demonstrated a less steep increase in the risk for LE neurologic impairment. CONCLUSIONS: LE neurologic impairment after FEVAR is strongly associated with LE ischemic time and CIA occlusive disease to a lumen of 8 mm or less. Our data indicate that, when the LE ischemic time is expected to exceed 2.5 hours (in patients with CIA stenosis) or 3 hours (in patients without CIA stenosis), measures to ensure LE perfusion should be given consideration.

Delayed gratification and adherence to exercise among patients with claudication.

Few studies have explicitly identified factors that explain an individual's willingness to engage in community-based exercise for claudication. Identifying the unique characteristics of those inclined toward physical activity would inform interventions that encourage walking. We examined the utility of behavioral economics-related concepts in understanding walking among Veterans with claudication. Patients who received care at the Michael E. DeBakey Veterans Affairs Medical Center in Houston, Texas, were surveyed on symptom severity, behavioral economics, stress, and depression. The primary outcome was a binary variable measuring current walking for exercise and defined as walking for at least 30 minutes every day. Multivariable logistic regression models were used to identify variables, both clinically and statistically significant, at a p-value < 0.05. Between April 2017 and March 2018, we received 148 (30%) responses. A total of 35% (n = 51) of respondents indicated that they walked recreationally for exercise compared to 65% (n = 94) who did not. Characteristics that were significantly associated with walking included regularly saving money (adjusted odds ratio (aOR) = 10.7, p = 0.001), seeking complex problem-solving (aOR = 0.12, p = 0.002), and severe symptoms (aOR = 0.24, p = 0.017). Individuals describing a preference for the future rather than immediate benefit also reported currently walking for exercise. Defining the characteristics of those who exercise may help inform strategies designed to increase walking among those who do not adhere to recommendations.

Successful Smoking Cessation Associated with Walking Behavior in Patients with Claudication.

BACKGROUND: Behavioral economics theories suggest that a preference for delayed benefits promotes positive behavioral change, a concept relevant to both smoking cessation and community-based exercise regimens for claudication. Given the high rate of smoking among older veterans, we were interested in examining the association between smoking cessation, exercise regimen adherence, and preferences for delayed versus immediate benefits. METHODS: Between April 2017 and March 2018, patients with claudication at the Michael E. DeBakey Veterans Affairs Medical Center in Houston, Texas, received questionnaires collecting information on social, behavioral, and psychological characteristics. A dual validation system, via the electronic medical record and survey data, measured the primary outcome-smoking cessation versus current smoking. Self-reported physical activity was measured through the validated Ainsworth's compendium of Physical Activities and binary survey questions. The Walking Impairment and Barratt's Impulsivity Questionnaires measured subjective symptom severity and behavioral economics factors, respectively. Multivariable, logistic regression models identified significant associations. RESULTS: The survey was mailed to 500 patients who met the eligibility criteria. We received responses from 148 individuals (30%), and 67 of 141 (48%) indicated that they had successfully quit smoking. In unadjusted comparisons, the median cognitive complexity score in the smoking cessation group was higher than that in the current smoking group. A greater proportion of patients who reported walking for exercise (n = 46) also reported successful smoking cessation (28/46, 61%). Among those who were not walking for exercise (n = 88), more individuals reported current smoking (49/88, 56%). In the multivariable model, individuals who had successfully stopped smoking were older (odds ratio [OR]: 7.59, P < 0.001), more likely to walk for exercise (OR: 3.94, P = 0.009), more interested in the future than in the present (OR: 1.73, P = 0.030), and more likely to regularly save money (OR: 3.49, P = 0.046). CONCLUSIONS: We found that participants who reported successful smoking cessation were more likely to report walking for exercise. Our findings suggest that adherence to walking may be less challenging for patients who have already successfully implemented and continue to implement another beneficial health behavior (smoking cessation). Patients with claudication who are current smokers may be less likely to adopt exercise recommendations.

Distal vein patch use and limb events after infragenicular prosthetic bypasses.

OBJECTIVE: In the absence of suitable autologous vein, the use of prosthetic grafts for infragenicular bypasses in peripheral arterial disease has become standard practice. The purpose of this study was to investigate whether creating a vein patch at the distal anastomosis would further improve patency and freedom from major adverse limb events (MALEs). Furthermore, we sought to investigate whether the use of a distal vein patch (DVP) was associated with lower rates of acute limb ischemia (ALI) for those presenting with occluded prosthetic bypass graft. METHODS: The cases of all patients undergoing infragenicular prosthetic bypass grafts between January 2009 and July 2016 were retrospectively reviewed. Demographics of the patients, clinical data, and outcomes (graft patency and MALEs) were collected. Patients were compared according to treatment group (DVP vs no DVP). A Cox regression analysis was used to analyze follow-up results. RESULTS: During the study period, a total of 373 patients underwent infragenicular bypass at our institution; of those, 93 (24.9%) had prosthetic grafts (DVP, 39; no DVP, 54). Overall, 92 (98.9%) patients were male; the mean age was 63.3 ± 6.6 years and did not differ between the two groups. Patients undergoing prosthetic bypass with DVP were more likely to have chronic obstructive pulmonary disease (38.5% vs 14.8%; P = .009) and less likely to have chronic kidney disease (2.6% vs 20.4%; P = .011). Follow-up data were available for all patients for a median of 7.8 months (range, 1-89 months). After adjustment for differences in demographics and clinical data between the two groups, when outcomes were analyzed, MALEs were significantly lower in the DVP group (35.9% vs 57.4%; odds ratio [OR], 0.4; 95% confidence interval [CI], 0.2-0.9; P = .041). Similarly, reintervention rates were significantly lower in the DVP group (30.8% vs 50.0%; OR, 0.4; 95% CI, 0.2-0.9; P = .044). There was a trend toward higher primary patency in the DVP group (46.2% vs 35.2%; OR, 1.5; 95% CI, 0.7-3.5; P = .206) and lower rates of ALI after bypass occlusion (30.0% vs 42.9%; OR, 0.6; 95% CI, 0.2-1.8; P = .345). A Cox regression time-to-event analysis revealed late separation of freedom from MALEs for DVP relative to no DVP (log rank, P = .269). CONCLUSIONS: In this evaluation of infragenicular prosthetic bypass grafts, the creation of a vein patch at the distal anastomosis was associated with lower reintervention rates and a trend toward improved primary patency and MALEs. Furthermore, for those presenting with occluded prosthetic bypass graft, the use of a DVP was associated with a trend toward lower rates of ALI.

The impact of foot infection on infrainguinal bypass outcomes in patients with chronic limb-threatening ischemia.

BACKGROUND: Despite advances in endovascular therapy, infrainguinal bypass continues to play a major role in achieving limb salvage. In this study, we sought to compare outcomes of infrainguinal bypass in patients with limb-threatening ischemia who presented with or without foot infection. METHODS: We conducted a retrospective cohort study of patients who underwent infrainguinal bypass for chronic limb-threatening ischemia at a single institution. End points of interest included long-term mortality, 45-day readmission, postoperative length of stay (LOS), major amputation, and time to wound healing. Multivariable Cox, logistic, and robust regressions were used to model time to event outcomes, readmission rates, and LOS. RESULTS: There were 454 infrainguinal bypass procedures analyzed. Demographics and baseline characteristics were similar, except congestive heart failure and diabetes were more common in the infection group. Presence of foot infection had no impact on mortality (hazard ratio [HR], 0.78; P = .243). Significant predictors of long-term mortality included increasing age, hypoalbuminemia, and congestive heart failure; preoperative use of clopidogrel was protective. Presence of foot infection was an independent predictor of major amputation. In the multiple regression model, the presence of foot infection was independently associated with amputation rate (HR, 2.14; 95% confidence interval, 1.42-3.22; P < .001); use of venous conduit and increasing age and body mass index were protective. Foot infection was an independent predictor of prolonged LOS (mean LOS was 1.54 days longer in patients with vs those without infection; P = .001). Other independent predictors of prolonged LOS included intraoperative blood loss and reoperation; history of continuous preoperative aspirin use and normal baseline renal function and albumin levels were associated with decreased LOS. Readmission was influenced by reoperation (odds ratio [OR], 2.51; P < .001) but not by presence of foot infection (OR, 1.21; P = .349). There was a strong trend for prolonged wound healing time in patients with diabetes (HR, 1.58; P = .05) but not in those with foot infection (OR, 0.74; P = .36). CONCLUSIONS: Among patients requiring infrainguinal bypass for limb-threatening ischemia, infection was more common in patients with diabetes and was a significant predictor of major amputation and prolonged LOS. Infection was not predictive of mortality, wound healing time, or readmission. These findings lend support to the inclusion of infection in risk stratification schemes for patients with chronic limb-threatening ischemia, as recommended in the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system, because of its adverse impacts on limb salvage.

Missing Data in Surgical Data Sets: A Review of Pertinent Issues and Solutions.

Incomplete data is a common problem in research studies. Methods to address missing observations in a data set have been extensively researched and described. Disseminating these methods to the greater research community is an ongoing effort. In this article, we describe some of the basic principles of missing data and identify practical, commonly used methods of adjustment relevant to surgical data sets. Through an example data set, we compare models generated through complete case analysis, single imputation (SI), and multiple imputation (MI). We also provide information on the steps to conduct MI using Stata IC. In our comparisons, we found that differences in odds ratios were greatest between the results from complete case analysis compared to the SI and MI models indicating that in this case the reduction in statistical power has a non-negligible effect on the parameter estimates. Odds ratio estimates from the SI and MI methods were largely similar. In some instances, when compared to the MI method, the SI method tended to overestimate effect sizes. While in this example the differences in odds ratios do not vary greatly between the SI and MI methods, there are clear indications supporting the use of MI over SI. By describing the issues surrounding missing data and the available options for adjustment, we hope to encourage the use of robust imputation methods for missing observations.