Validated prediction model for severe groin wound infection after lower extremity revascularization procedures

Prediction Models for Forecasting Risk of Development of Surgical Site Infection after Lower Limb Revascularization Surgery: A Systematic Review

BACKGROUND

Surgical site infections (SSIs) are a common and potentially preventable complication of lower limb revascularization surgery associated with increased healthcare resource utilization and patient morbidity. We conducted a systematic review to evaluate multivariable prediction models designed to forecast risk of SSI development after these procedures.

METHODS

After protocol registration (CRD42022331292), we searched MEDLINE, EMBASE, CENTRAL, and Evidence-Based Medicine Reviews (inception to April 4th, 2023) for studies describing multivariable prediction models designed to forecast risk of SSI in adults after lower limb revascularization surgery. Two investigators independently screened abstracts and full-text articles, extracted data, and assessed risk of bias. A narrative synthesis was performed to summarize predictors included in the models and their calibration and discrimination, validation status, and clinical applicability.

RESULTS

Among the 6,671 citations identified, we included 5 studies (n = 23,063 patients). The included studies described 5 unique multivariable prediction models generated through forward selection, backward selection, or Akaike Information Criterion-based methods. Two models were designed to predict any SSI and 3 Szyilagyi grade II (extending into subcutaneous tissue) SSI. Across the 5 models, 18 adjusted predictors (10 of which were preoperative, 3 intraoperative, and 5 postoperative) significantly predicted any SSI and 14 adjusted predictors significantly predict Szilagyi grade II SSI. Female sex, obesity, and chronic obstructive pulmonary disease significantly predicted SSI in more than one model. All models had a "good fit" according to the Hosmer-Lemeshow test (P > 0.05). Model discrimination was quantified using the area under the curve, which ranged from 0.66 to 0.75 across models. Two models were internally validated using non-exhaustive twofold cross-validation and bootstrap resampling. No model was externally validated. Three studies had a high overall risk of bias according to the Prediction model Risk Of Bias ASsessment Tool (PROBAST).

CONCLUSIONS

Five multivariable prediction models with moderate discrimination have been developed to forecast risk of SSI development after lower limb revascularization surgery. Given the frequency and consequences of SSI after these procedures, development and external validation of novel prediction models and comparison of these models to the existing models evaluated in this systematic review is warranted.

Antimicrobial stewardship program for gastrointestinal surgeries at a Vietnamese tertiary hospital

Background

Antimicrobial Stewardship Programs (ASP) have been applied widely in high-resource countries to prevent surgical site infections (SSI). Evidence favoring ASP interventions (ASPi) in gastrointestinal surgeries from low and middle-income countries has been limited, especially in antimicrobial prophylaxis. We aimed to investigate this gap at a Vietnamese tertiary hospital.

Methods

We conducted a retrospective cohort study on patients undergoing clean-contaminated surgeries in 2015 who received standard of care (SoC) or SoC + ASPi. Primary outcome was 30-day SSI incidence. Secondary outcomes included length of stay (LoS) after surgery (days), cost of antibiotics, and cost of treatment (USD). Results were controlled for multiplicity and reported with treatment effect and 95% confidence interval (95%CI). A predictive model was built and cross-validated to detect patients at high risk of SSI.

Results

We included 395 patients for analysis (48.1% being female, mean age 49.4 years). Compared to patients receiving SoC, those with SoC + ASPi had a lower incidence of 30-day SSI (-8.8, 95%CI: -16.0 to -1.6, p = 0.042), shorter LoS after surgery (-1.1 days, 95%CI: -1.8 to -0.4, p = 0.004), and lower cost of antibiotics (-37.3 USD, 95%CI: -59.8 to -14.8, p = 0.012) and treatment (-191.1 USD, 95%CI: -348.4 to -33.8, p = 0.042). We estimated that by detecting patients at high risk of SSI with the predictive model and providing prophylactic measures, we could save 398120.7 USD per 1,000 cases of SSI.

Conclusion

We found that ASPi were associated with a reduction in risks of SSI, hospital stays, and cost of antibiotics/treatment in a Vietnamese tertiary hospital.

Using Machine Learning (XGBoost) to Predict Outcomes After Infrainguinal Bypass for Peripheral Artery Disease

OBJECTIVE

To develop machine learning (ML) algorithms that predict outcomes after infrainguinal bypass.

BACKGROUND

Infrainguinal bypass for peripheral artery disease carries significant surgical risks; however, outcome prediction tools remain limited.

METHODS

The Vascular Quality Initiative database was used to identify patients who underwent infrainguinal bypass for peripheral artery disease between 2003 and 2023. We identified 97 potential predictor variables from the index hospitalization [68 preoperative (demographic/clinical), 13 intraoperative (procedural), and 16 postoperative (in-hospital course/complications)]. The primary outcome was 1-year major adverse limb event (composite of surgical revision, thrombectomy/thrombolysis, or major amputation) or death. Our data were split into training (70%) and test (30%) sets. Using 10-fold cross-validation, we trained 6 ML models using preoperative features. The primary model evaluation metric was the area under the receiver operating characteristic curve (AUROC). The top-performing algorithm was further trained using intraoperative and postoperative features. Model robustness was evaluated using calibration plots and Brier scores.

RESULTS

Overall, 59,784 patients underwent infrainguinal bypass, and 15,942 (26.7%) developed 1-year major adverse limb event/death. The best preoperative prediction model was XGBoost, achieving an AUROC (95% CI) of 0.94 (0.93-0.95). In comparison, logistic regression had an AUROC (95% CI) of 0.61 (0.59-0.63). Our XGBoost model maintained excellent performance at the intraoperative and postoperative stages, with AUROCs (95% CI's) of 0.94 (0.93-0.95) and 0.96 (0.95-0.97), respectively. Calibration plots showed good agreement between predicted and observed event probabilities with Brier scores of 0.08 (preoperative), 0.07 (intraoperative), and 0.05 (postoperative).

CONCLUSIONS

ML models can accurately predict outcomes after infrainguinal bypass, outperforming logistic regression.

Risk Factors for Surgical Site Infection after Lower Limb Revascularisation Surgery: a Systematic Review and Meta-Analysis of Prognostic Studies

OBJECTIVE

To systematically review and meta-analyse adjusted risk factors for surgical site infection (SSI) after lower limb revascularisation surgery.

DATA SOURCES

MEDLINE, Embase, Evidence Based Medicine Reviews, and the Cochrane Central Register of Controlled Trials (inception to 28 April 2022).

REVIEW METHODS

Systematic review and meta-analysis conducted according to PRISMA guidelines. After protocol registration, databases were searched. Studies reporting adjusted risk factors for SSI in adults who underwent lower limb revascularisation surgery for peripheral artery disease were included. Adjusted odds ratios (ORs) were pooled using random effects models. GRADE was used to assess certainty.

RESULTS

Among 6 377 citations identified, 50 studies (n = 271 125 patients) were included. The cumulative incidence of SSI was 12 (95% confidence interval [CI] 10 - 13) per 100 patients. Studies reported 139 potential SSI risk factors adjusted for a median of 12 (range 1 - 69) potential confounding factors. Risk factors that increased the pooled adjusted odds of SSI included: female sex (pooled OR 1.41, 95% CI 1.20 - 1.64; high certainty); dependent functional status (pooled OR 1.18, 95% CI 1.03 - 1.35; low certainty); being overweight (pooled OR 1.82, 95% CI 1.29 - 2.56; moderate certainty), obese (pooled OR 2.20, 95% CI 1.44 - 3.36; high certainty), or morbidly obese (pooled OR 1.65, 95% CI 1.08 - 2.52; moderate certainty); chronic obstructive pulmonary disease (pooled OR 1.42, 95% CI 1.17 - 1.71; high certainty); chronic limb threatening ischaemia (pooled OR 1.67, 95% CI 1.22 - 2.29; moderate certainty); chronic kidney disease (pooled OR 2.13, 95% CI 1.18 - 3.83; moderate certainty); intra-operative (pooled OR 1.23, 95% CI 1.02 - 1.49), peri-operative (pooled OR 1.92, 95% CI 1.27 - 2.90), or post-operative (pooled OR 2.21, 95% CI 1.44 - 3.39) blood transfusion (moderate certainty for all); urgent or emergency surgery (pooled OR 2.12, 95% CI 1.22 - 3.70; moderate certainty); vein bypass and or patch instead of endarterectomy alone (pooled OR 1.86, 95% CI 1.33 - 2.59; moderate certainty); an operation lasting ≥ 3 hours (pooled OR 1.86, 95% CI 1.33 - 2.59; moderate certainty) or ≥ 5 hours (pooled OR 1.60, 95% CI 1.18 - 2.17; moderate certainty); and early or unplanned re-operation (pooled OR 4.50, 95% CI 2.18 - 9.32; low certainty).

CONCLUSION

This systematic review identified evidence informed SSI risk factors following lower limb revascularisation surgery. These may be used to develop improved SSI risk prediction tools and to identify patients who may benefit from evidence informed SSI prevention strategies.

Predicting wound complications following lower extremity revascularization

OBJECTIVE

The aim of this study was to create a simple risk score to identify factors associated with wound complications after infrainguinal revascularization.

METHODS

The Veterans Affairs Surgical Quality Improvement Program national data set was queried from 2005 to 2021 to identify 22,114 patients undergoing elective open revascularization for peripheral arterial disease (claudication, rest pain, tissue loss) or peripheral aneurysm. Emergency and trauma cases were excluded. The data set was divided into a two-thirds derivation set and one-third validation set to create a risk prediction model. The primary end point was wound complication (wound dehiscence, superficial/deep wound surgical site infection). Eight independent risk factors for wound complications resulted from the model and were assigned whole number integer risk scores. Summary risk scores were collapsed into categories and defined as low (0-3 points), moderate (4-7 points), high (8-11 points), and very high (>12 points).

RESULTS

The wound complication rate in the derivation data set was 9.7% (n = 1428). Predictors of wound complication included age ≤73 (odds ratio [OR], 1.25; 95% confidence interval [CI], 1.08-1.46), body mass index ≥35 kg/m2 (OR, 1.99; 95% CI, 1.68-2.36), non-Hispanic White (vs others: OR, 1.48; 95% CI, 1.30-1.69), diabetes (OR, 1.23; 95% CI, 1.10-1.37), white blood cell count >9900/mm3 (OR, 1.18; 95% CI, 1.03-1.35), absence of coronary artery disease (OR, 1.27; 95% CI, 1.03-1.35), operative time >6 hours (OR, 1.20; 95% CI, 1.05-1.37), and undergoing a femoral endarterectomy in conjunction with bypass (OR, 1.34; 95% CI, 1.14-1.57). In both the derivation and validation sets, wound complications correlated with risk category. Among the defined categories in the derivation set, wound complication rates were 4.5% for low-risk patients, 8.5% for moderate-risk patients, 13.8% for high-risk patients, and 23.8% for very high-risk patients, with similar results for the internal validation data set. Operative indication did not independently associate with wound complications. Patients with wound complications had higher rates of reoperation and graft failure.

CONCLUSIONS

This risk prediction model uses easily obtainable clinical metrics that allow for informed discussion of wound complication risk for patients undergoing open infrainguinal revascularization.

Predicting outcomes following lower extremity open revascularization using machine learning

Lower extremity open revascularization is a treatment option for peripheral artery disease that carries significant peri-operative risks; however, outcome prediction tools remain limited. Using machine learning (ML), we developed automated algorithms that predict 30-day outcomes following lower extremity open revascularization. The National Surgical Quality Improvement Program targeted vascular database was used to identify patients who underwent lower extremity open revascularization for chronic atherosclerotic disease between 2011 and 2021. Input features included 37 pre-operative demographic/clinical variables. The primary outcome was 30-day major adverse limb event (MALE; composite of untreated loss of patency, major reintervention, or major amputation) or death. Our data were split into training (70%) and test (30%) sets. Using tenfold cross-validation, we trained 6 ML models. Overall, 24,309 patients were included. The primary outcome of 30-day MALE or death occurred in 2349 (9.3%) patients. Our best performing prediction model was XGBoost, achieving an area under the receiver operating characteristic curve (95% CI) of 0.93 (0.92-0.94). The calibration plot showed good agreement between predicted and observed event probabilities with a Brier score of 0.08. Our ML algorithm has potential for important utility in guiding risk mitigation strategies for patients being considered for lower extremity open revascularization to improve outcomes.

Risk factors and consequences of wound complications following sartorius flap reconstruction

OBJECTIVE

Groin wound complications are common following vascular surgery and can lead to significant patient morbidity. Sartorius muscle flap coverage may help to prevent vascular graft infection in the setting of wound dehiscence or infection. However, risk factors and consequences of wound complications following sartorius flap reconstruction remain incompletely investigated.

METHODS

We retrospectively queried all patients who underwent sartorius flap reconstruction at a tertiary academic medical center. Data collected included patient demographics, medical comorbidities, surgical indication, index vascular procedure, and postoperative outcomes. The primary outcome was wound complication following sartorius flap procedure, which was defined as groin wound infection, dehiscence, or lymphocutaneous fistula.

RESULTS

From 2012 to 2022, a total of 113 patients underwent sartorius flap reconstruction. Of these, 66 (58.4%) were performed after the development of a prior groin complication, and 47 (41.6%) were prophylactic. A total of 88 patients (77.9%) had a prosthetic bypass graft adjacent to the flap. Twenty-nine patients (25.7%) suffered a wound complication following sartorius flap reconstruction, including 14 (12.4%) with wound dehiscence, 13 (11.5%) with wound infection, and two (1.8%) with lymphocutaneous fistula. Patients with wound complications had a higher body mass index (28.8 vs 26.4 kg/m2; P =.03) and more frequently active smokers (86.2% vs 66.7%; P = .04). Additionally, patients with wound complications had a higher unplanned 30-day hospital readmission rates (72.4% vs 15.5%; P < .001), reintervention rates (75.9% vs 8.3%; P < .001), and re-do flap reconstruction rates (13.8% vs 2.4%; P = .02). On multivariable analysis, higher body mass index was independently associated with post-flap wound complications (adjusted odds ratio [aOR], 1.01; 95% confidence interval [CI], 1.001-1.03; P = .037). Consequently, wound complications were associated with both surgical reintervention (aOR, 35.4; 95% CI, 9.9-126.3; P < .001) and unplanned hospital readmission (aOR, 17.8; 95% CI, 5.9-54.1; P < .001).

CONCLUSIONS

Sartorius flap reconstruction is an effective adjunct in facilitating wound healing of groin wounds. However, wound complications are common following sartorius flap reconstruction and may be associated with reintervention and unplanned hospital readmission. These data support the judicious and thoughtful utilization of sartorius flap procedures among high-risk patients.

A framework for perioperative care for lower extremity vascular bypasses: A Consensus Statement by the Enhanced Recovery after Surgery (ERAS®) Society and Society for Vascular Surgery

The Society for Vascular Surgery and the Enhanced Recovery After Surgery (ERAS) Society formally collaborated and elected an international, multi-disciplinary panel of experts to review the literature and provide evidence-based suggestions for coordinated perioperative care for patients undergoing infrainguinal bypass surgery for peripheral artery disease. Structured around the ERAS core elements, 26 suggestions were made and organized into preadmission, preoperative, intraoperative, and postoperative sections.

Systematic review of groin wound surgical site infection incidence after arterial intervention

The objectives were to determine the surgical site infection incidence (including superficial/deep) fter arterial intervention through non-infected groin incisions and identify variables associated with incidence. MEDLINE, EMBASE and CENTRAL databases were searched for randomised controlled trials and observational studies of adults undergoing arterial intervention through a groin incision and reported surgical site infection. Infection incidence was examined in subgroups, variables were subjected to meta-regression. One hundred seventeen studies reporting 65 138 groin incisions in 42 347 patients were included. Overall surgical site infection incidence per incision was 8.1% (1730/21 431): 6.3% (804/12 786) were superficial and 1.9% (241/12 863) were deep. Superficial infection incidence was higher in randomised controlled trials (15.8% [278/1762]) compared with observational studies (4.8% [526/11 024]); deep infection incidence was similar (1.7% (30/1762) and 1.9% (211/11 101) respectively). Aneurysmal pathology (β = -10.229, P < .001) and retrospective observational design (β = -1.118, P = .002) were associated with lower infection incidence. Surgical site infection being a primary outcome was associated with a higher incidence of surgical site infections (β = 3.429, P = .017). The three-fold higher incidence of superficial surgical site infection reported in randomised controlled trials may be because of a more robust clinical review of patients. These results should be considered when benchmarking practice and could inform future trial design.

Surgical site infection after open lower extremity revascularization associated with doubled rate of major limb amputation

OBJECTIVE

Surgical site infection (SSI) after open lower extremity revascularization is a relatively common complication associated with increased hospital stays, graft infection, and in severe cases, graft loss. Although the short-term effects of SSI can be significant, it has not been considered a complication that increases major limb amputation. The purpose of this study was to determine the association of SSI with outcomes in patients undergoing surgical revascularization for peripheral arterial disease.

METHODS

We analyzed nationwide Vascular Quality Initiative (VQI) data from the infrainguinal bypass module from 2003 to 2017. The cohort included adults who underwent open lower extremity bypass for symptomatic peripheral arterial disease and had at least one follow-up record. Weighted Kaplan-Meier curves and Cox proportional hazards regression were used to assess the association between SSI and 1-year mortality and major limb amputation. Inverse-probability of treatment weights were used to account for differences in demographics and patient characteristics and allow for 'adjusted' Kaplan-Meier curves.

RESULTS

The analysis included 21,639 patients, and 1155 (5%) had a reported SSI within 30 days of surgery. Patients with SSI were more likely be obese (41% vs 30%), but there were no other clinically relevant differences between demographics, comorbidities, and bypass details. After weighting, patients with SSI were almost twice as likely to undergo major amputation by 6 months (hazard ratio, 1.84; 95% confidence interval, 1.07-3.17). The association with SSI and increased amputation rates persisted at 1 year. The association of SSI on amputation was no different based on preoperative Rutherford class (P = .91). The association between SSI and 1-year mortality rate was not statistically significant (hazard ratio, 1.15; 95% confidence interval, 0.91-1.46).

CONCLUSIONS

SSI is more common in obese patients, and patients who develop an SSI are observed to have a significantly increased rate of limb amputation after open lower extremity revascularization.

Risk Factors for Surgical Site Infection After Lower Limb Revascularization Surgery in Adults With Peripheral Artery Disease: Protocol for a Systematic Review and Meta-analysis

BACKGROUND

Surgical site infections (SSIs) are common, costly, and associated with increased morbidity and potential mortality after lower limb revascularization surgery (ie, arterial bypass, endarterectomy, and patch angioplasty). Identifying evidence-informed risk factors for SSI in patients undergoing these surgeries is therefore important.

OBJECTIVE

The aim of this study is to conduct a systematic review and meta-analysis of prognostic studies to identify, synthesize, and determine the certainty in the cumulative evidence associated with reported risk factors for early and delayed SSI after lower limb revascularization surgery in adults with peripheral artery disease.

METHODS

We will search MEDLINE, Embase, the seven databases in Evidence-Based Medicine Reviews, review articles identified during the search, and included article bibliographies. We will include studies of adults (aged ≥18 years) with peripheral artery disease that report odds ratios, risk ratios, or hazard ratios adjusted for the presence of other risk factors or confounding variables and relating the potential risk factor of interest to the development of SSI after lower limb revascularization surgery. We will exclude studies that did not adjust for confounding, exclusively examined certain high-risk patient cohorts, or included >20% of patients who underwent surgery for indications other than peripheral artery disease. The primary outcomes will be early (in-hospital or ≤30 days) SSI and Szilagyi grade I (cellulitis involving the wound), grade II (infection involving subcutaneous tissue), and grade III (infection involving the vascular graft) SSI. Two investigators will independently extract data and evaluate the study risk of bias using the Quality in Prognosis Studies tool. Adjusted risk factor estimates with similar definitions will be pooled using DerSimonian and Laird random-effects models. Heterogeneity will be explored using stratified meta-analyses and meta-regression. Finally, we will use the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach to determine certainty in the estimates of association between reported risk factors and the development of SSI.

RESULTS

The protocol was registered in PROSPERO (International Prospective Register of Systematic Reviews). We will execute the peer-reviewed search strategy on June 30, 2021, and then complete the review of titles and abstracts and full-text articles by July 30, 2021, and September 15, 2021, respectively. We will complete the full-text study data extraction and risk of bias assessment by November 15, 2021. We anticipate that we will be able to submit the manuscript for peer review by January 30, 2022.

CONCLUSIONS

This study will identify, synthesize, and determine the certainty in the cumulative evidence associated with risk factors for early and delayed SSI after lower limb revascularization surgery in patients with peripheral artery disease. The results will be used to inform practice, clinical practice statements and guidelines, and subsequent research.

TRIAL REGISTRATION

PROSPERO International Prospective Register of Systematic Reviews CRD42021242557; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=242557.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/28759.

Groin Wound Infection after Vascular Exposure (GIVE) Risk Prediction Models: Development, Internal Validation, and Comparison with Existing Risk Prediction Models Identified in a Systematic Literature Review

OBJECTIVE

This study aimed to develop and internally validate risk prediction models for predicting groin wound surgical site infections (SSIs) following arterial intervention and to evaluate the utility of existing risk prediction models for this outcome.

METHODS

Data from the Groin wound Infection after Vascular Exposure (GIVE) multicentre cohort study were used. The GIVE study prospectively enrolled 1 039 consecutive patients undergoing an arterial procedure through 1 339 groin incisions. An overall SSI rate of 8.6% per groin incision, and a deep/organ space SSI rate of 3.8%, were reported. Eight independent predictors of all SSIs, and four independent predictors of deep/organ space SSIs were included in the development and internal validation of two risk prediction models. A systematic search of the literature was conducted to identify relevant risk prediction models for their evaluation.

RESULTS

The "GIVE SSI risk prediction model" ("GIVE SSI model") and the "GIVE deep/organ space SSI risk prediction model" ("deep SSI model") had adequate discrimination (C statistic 0.735 and 0.720, respectively). Three other groin incision SSI risk prediction models were identified; both GIVE risk prediction models significantly outperformed these other risk models in this cohort (C statistic 0.618 - 0.629; p < .050 for inferior discrimination in all cases).

CONCLUSION

Two models were created and internally validated that performed acceptably in predicting "all" and "deep" groin SSIs, outperforming current existing risk prediction models in this cohort. Future studies should aim to externally validate the GIVE models.

The use of vascularised muscle flaps for treatment or prevention of wound complications following arterial surgery in the groin

Wound complications following arterial surgery in the groin are relatively common and can result in significant morbidity and mortality. Vascularised muscle flaps (VMF) may be used as an adjunct to aid healing, either to manage complications or prophylactically. This series describes 46 patients who received sartorius or gracilis muscle flaps, of which 70% were performed as a salvage procedure to treat complications ranging from wound breakdown to vascular graft infection. The remaining 30% were performed at the time of the arterial surgery in patients with risk factors such as re‐do surgery or immunosuppression. The peri‐operative mortality rate was 9% and the major amputation rate was 26%, reflecting the complexity of patients that require intervention. Overall, 85% achieved successful healing in the groin without the need for further treatment following VMF. Only one case of flap necrosis occurred. Wound healing complications occurred more commonly after sartorius muscle flaps. The gracilis muscle offers a bulkier mass and greater mobility and so may be preferable, particularly for larger groin defects. This series has shown that VMF offer a safe and reliable option for selected cases to achieve wound healing in the groin in patients with often significant co‐morbidities.

Living in a Food Desert is Associated with 30-day Readmission after Revascularization for Chronic Limb-Threatening Ischemia

BACKGROUND

Living in a food desert has been associated with increased cardiovascular risk; however, its impact on vascular surgery outcomes is unknown. This study hypothesized that living in a food desert would be associated with increased postoperative complications in patients undergoing revascularization for chronic limb-threatening ischemia (CLTI).

METHODS

This was a single-center retrospective analysis of open and endovascular infrainguinal revascularization for CLTI between April 2013 and December 2015. A food desert was defined using the US Department of Agriculture's Food Access Research Atlas. Bivariate analyses were performed appropriate to the data. Binary logistic regression was performed assessing the association of food desert status with 30-day postoperative complications.

RESULTS

In total, 152 cases were included, of which 17% (n = 26) resided in food deserts. Patients in the food desert cohort were less likely to be low income (27% vs. 54%, P = 0.01). Living in a food desert was associated with increased 30-day readmission [(39% vs. 20%, P = 0.04), unadjusted OR: 2.5 (CI: 1.0-6.2)]. FD cases also had a higher proportion of wound complications [12 (46%) vs. 28 (22%), P = 0.01)]. The overall wound complication rate was 27% with the majority being due to infections (63%). On multivariable analysis, food desert status remained associated with increased odds of 30-day readmission (OR: 2.7, CI: 1.2-8.4, P = 0.047). Reasons for readmission in the food desert group were all due to wound complications (100% vs. 72%, P = 0.08).

CONCLUSIONS

Living in a food desert was associated with nearly three times the odds of 30-day readmission after lower extremity revascularization for CLTI. This increase in readmission may be explained through increased wound complications. These findings support considering access to healthy food as a potential modifiable risk factor for adverse outcomes, particularly in CLTI revascularization.

Outcomes of routine use of percutaneous access with large-bore introducer sheaths (>21F outer diameter) during endovascular aneurysm repair

OBJECTIVE

The objective of this study was to evaluate the performance of percutaneous femoral access with large-bore sheaths (>21F outer diameter) mainly employed for thoracic and thoracoabdominal aortic endovascular treatment and to stratify the outcomes on the basis of the introducer size.

METHODS

Between December 2015 and December 2018, all consecutive patients who received endovascular repair through a percutaneous approach with a suture-mediated vascular closure device (VCD) and the preclose technique were included in a retrospective single-center study called Totally Percutaneous Approach to Endovascular Treatment of Aortic Aneurysms (PEVAR-PRO). The morphologic characteristics of the access vessels and patients' demographics were recorded, and 30-day closure success was defined as the primary end point. Analysis of the closure success comparing large-bore sheaths vs small-bore sheaths (≤21F outer diameter) was performed after 1:1 propensity score matching of preoperative confounding variables.

RESULTS

The closure success rate of the entire study cohort was 94% (622 femoral accesses in 360 patients; median age, 74 years; 84% male). Univariate analysis identified eight different factors associated with failure, but only two remained significant on multivariate analysis: diabetes (odds ratio [OR], 2.8; 95% confidence interval [CI], 1.3-6.2; P = .011) and common femoral artery stenosis >50% (OR, 4.5; 95% CI, 1.3-13.7; P = .019). After propensity score matching (1:1, 172 femoral accesses per group), closure success rate was not significantly different between large-bore and small-bore sheaths (90.7% vs 93.0%; P = .43). Multivariate analysis of the large-sheath group identified two factors associated with failure: small (<9 mm) femoral arteries (OR, 6.9; 95% CI, 1.5-31.6; P = .13) and access vessel calcifications involving more than one-third of the circumference (OR, 7.9; 95% CI, 2.1-29.4; P = .002). Neither previous femoral cutdown (44 accesses [23%]) nor percutaneous closure with VCDs (38 accesses [20%]) affected the closure success rate in the large-sheath group. Closure failure did not significantly increase the need for postoperative blood transfusions or hospital length of stay.

CONCLUSIONS

Off-label use of VCDs and the preclose technique for percutaneous approach with large-bore sheaths needed for complex aortic endovascular procedures is safe and feasible. Closure success rate is not significantly different from that obtained with on-label application of VCDs with smaller sheaths.

Outcomes after Open Lower Extremity Revascularization in Patients with Critical Limb Ischemia

BACKGROUND

For decades, open intervention was the treatment of choice in patients requiring lower extremity revascularization. In the endovascular era, however, open and endovascular revascularization are options. The implications of prior revascularization on the outcomes for subsequent revascularization are not known. In the present study, we evaluated 30-day outcomes after open lower extremity revascularization for critical limb ischemia (CLI) in those who had previous interventions.

METHODS

The 2012-2017 open lower extremity bypass Participant User Data Files from the National Surgical Quality Improvement Program were used to identify a cohort of patients with CLI. Patients whose operation was considered emergent were excluded from the analysis. Patients were stratified on whether they had a previous open or endovascular intervention or undergoing a primary revascularization. The primary outcome measure was 30-day major adverse limb events (MALEs). Secondary outcomes included major adverse cardiac events (MACEs) and wound complications.

RESULTS

A total of 12,668 patients met study criteria with 59.6% (n = 7,549) undergoing a primary open revascularization, 22.4% (n = 2,839) having a prior endovascular intervention, and 18.0% (n = 2,280) having a prior open revascularization. There were notable differences in the baseline characteristics between the 3 groups. In addition, there were differences in the reason for intervention (rest pain versus tissue loss), type of revascularization, and type of conduit used between the 3 groups. After adjustment, a prior open revascularization was significantly associated with 30-day MALE when compared with a primary revascularization (adjusted odds ratio, 1.69; 95% confidence interval, 1.47-1.94; P < 0.001) and prior endovascular intervention (adjusted odds ratio, 1.76; 95% confidence interval, 1.46-2.12; P < 0.001). There were no differences in outcomes between primary revascularization and prior endovascular patients. There were no differences between MACEs or wound complications between the 3 groups.

CONCLUSIONS

A prior endovascular intervention does not seem to accrue any additional short-term risk when compared with primary revascularization, suggesting an endovascular-first approach may be a safe strategy in patients with CLI. However, a prior open intervention is significantly associated with 30-day MALE in patients undergoing redo open revascularization, which may be related to the rapid decline in patients once they have exhausted their best open revascularization option.

Discharge to a Post-Acute Care Facility after Emergent Femoral Artery Repair is Not Protective Against Wound Complications

BACKGROUND

Access site complication is the most common adverse event after endovascular intervention, and when emergent operative repair of the common femoral artery (CFA) is needed, patient morbidity can be significantly increased. The intent of this project was to identify predictors of wound events after emergent operative repair of the CFA due to an access site complication. It was hypothesized that patients discharged to a facility would benefit from an ongoing relationship with healthcare professionals as evidenced by more consistent follow-up and lower wound complication rates.

METHODS

Patients who had a percutaneous CFA access complication and required emergent open CFA repair at an academic medical institution between 2015 and 2018 were included, and the charts were reviewed retrospectively. Primary outcomes included wound complication and outpatient compliance with vascular surgery clinic visit. Dichotomous groups were evaluated by the chi-squared test, and continuous variables were evaluated by Student's t-test. Univariate and multivariate regression analyses were completed to assess risk factors contributing to wound event or failure of clinic follow-up.

RESULTS

Forty-four patients were identified with emergent CFA repair due to an access complication between July 2015 and June 2018. Among this population, 33% of patients had wound complications and 27% were discharged to a facility. Among those discharged to a facility, the rate of follow-up to the vascular surgeon's clinic was significantly lower than those discharged to home (40% vs. 85%, P < 0.05), and the incidence of wound complications appeared greater but did not reach statistical significance (50% vs. 27%, P = 0.11). Univariate analysis indicated that kidney disease, albumin <3 g/dL, and current smoking were predictive of wound complication, whereas on multivariate analysis, only kidney disease remained predictive (P < 0.05, odds ratio = 22). The modified frailty index (mFI) was not predictive of wound complications or compliance with follow-up. However, mFI did approach statistical significance when predicting discharge to a facility.

CONCLUSIONS

Despite the availability of medical personnel to arrange transportation and provide wound care in post-acute care facilities, patients who were discharged to a facility after CFA injury requiring emergent repair experienced lower compliance with clinic follow-up and may have suffered more wound complications. Strategies to improve compliance with patient follow-up and wound healing in patients sent to post-acute care facilities are warranted.

Prophylactic antibiotic bundle compliance and surgical site infections: an artificial neural network analysis

Background

Best practice "bundles" have been developed to lower the occurrence rate of surgical site infections (SSI's). We developed artificial neural network (ANN) models to predict SSI occurrence based on prophylactic antibiotic compliance.

Methods

Using the American College of Surgeons National Quality Improvement Program (ACS-NSQIP) Tampa General Hospital patient dataset for a six-month period, 780 surgical procedures were reviewed for compliance with SSI guidelines for antibiotic type and timing. SSI rates were determined for patients in the compliant and non-compliant groups. ANN training and validation models were developed to include the variables of age, sex, steroid use, bleeding disorders, transfusion, white blood cell count, hematocrit level, platelet count, wound class, ASA class, and surgical antimicrobial prophylaxis (SAP) bundle compliance.

Results

Overall compliance to recommended antibiotic type and timing was 92.0%. Antibiotic bundle compliance had a lower incidence of SSI's (3.3%) compared to the non-compliant group (8.1%, p = 0.07). ANN models predicted SSI with a 69-90% sensitivity and 50-60% specificity. The model was more sensitive when bundle compliance was not used in the model, but more specific when it was. Preoperative white blood cell (WBC) count had the most influence on the model.

Conclusions

SAP bundle compliance was associated with a lower incidence of SSI's. In an ANN model, inclusion of the SAP bundle compliance reduced sensitivity, but increased specificity of the prediction model. Preoperative WBC count had the most influence on the model.

Study protocol for the groin wound infection after vascular exposure (GIVE) audit and multicentre cohort study

INTRODUCTION

Surgical site infections (SSIs) following groin incision for arterial exposure are commonplace and a significant cause of morbidity and mortality following major arterial surgery. Published incidence varies considerably. The primary aim of GIVE will be to compare individual units' practice with established guidelines from The National Institute for Health and Care Excellence (NICE). Secondary aims will be to describe the contemporary rate of SSI in patients undergoing groin incision for arterial exposure, to identify risk factors for groin wound infection, to examine the value of published tools in the prediction of SSI, to identify areas of equipoise which could be examined in future efficacy/effectiveness trials and to compare UK SSI rates with international centres.

METHODS AND ANALYSIS

This international, multicentre, prospective observational study will be delivered via the Vascular and Endovascular Research Network (VERN). Participating centres will identify all patients undergoing clean emergency or elective groin incision(s) for arterial intervention during a consecutive 3-month period. Follow up data will be captured at 90 days after surgery. SSIs will be defined according to the Centres for Disease Control and Prevention (CDC) criteria. Data will be gathered centrally using an anonymised electronic data collection tool or secure email transfer.

ETHICS AND DISSEMINATION

This study will be registered as a clinical audit at all participating UK centres; research ethics approval is not required. National leads will oversee the appropriate registration and approvals in countries outside the UK as required. Site specific reports of SSI rates will be provided to each participating centre. Study results will be disseminated locally at each site, publicised on social media and submitted for peer-reviewed publication.

Variation in timing and type of groin wound complications highlights the need for uniform reporting standards

BACKGROUND

Groin wound infections represent a substantial source of patients' morbidity and resource utilization. Definitions and reporting times of groin infections are poorly standardized, which limits our understanding of the true scope of the problem and potentially leads to event under-reporting. Our objective was to investigate the timing and variation of groin wound complications after vascular surgery.

METHODS

We reviewed all patients who underwent vascular surgery with a groin incision at our institution during 2013 (N = 256; 32% female; mean age, 68.8 years). We analyzed patient- and procedure-level variables. Our primary outcome was any groin complication within 180 days. We classified groin-related events as major (hospital readmission or reoperation for groin wound) or minor (wound opened in clinic, initiation of antibiotics specifically for a groin wound, or new groin hematoma or wound drainage).

RESULTS

The Kaplan-Meier estimated rate of groin complications at 180 days was 23% (n = 53/256); 29 (54%) were major and 24 (46%) were minor. The Kaplan-Meier 30-day event rate was 13% for any complication and only 3% for major complications, indicating that most events occurring within the first 30 days did not require readmission or reoperation. By 180 days, the overall complication rate rose to 23% and the major event rate to 14%, indicating that nearly all complications occurring after 30 days required readmission or reoperation. Those with a groin complication more commonly had tissue loss (23% vs 12%; P = .05), underwent infrainguinal bypass (42% vs 22%; P=.004), had a redo incision (32% vs 18%; P = .03), and had a longer operation (77% vs 65% surgery >200 minutes; P = .07). There were no significant differences in patients' comorbidities, skin closure, dressing type, prosthetic implants, hemostatic agents, or discharge status.

CONCLUSIONS

Whereas >20% of patients suffered a groin complication, nearly half of these events occurred after 30 days. Standardized reporting measures limited to 30-day events or infection definitions that are limited to the need for antibiotic use may misrepresent the true infection rate and thus highlight the need for uniform reporting standards.

Vascular Graft Infection: Incidence and Potential Risk Factors

PURPOSE

The purpose of this study was to identify factors that increase the risk of vascular graft infections (VGI) in patients following abdominal or lower extremity revascularization surgery.

DESIGN

Retrospective, descriptive study.

METHODS

We reviewed the electronic health records of 223 patients who had undergone abdominal or lower extremity revascularization procedures from July 2012 to November 2014, looking for factors associated with VGI. We reviewed 28 preoperative, intraoperative, and post-operative factors. Descriptive statistics (mean, range, and standard deviation) were used to describe the sample; χ was used to determine correlations between the risk factors and subsequent VGIs. The level of significance was determined at P = .05, with a confidence level of 95%.

RESULTS

We identified 33 cases of VGIs for the 223 charts reviewed, yielding an incidence rate of 15%. Seventeen of the 33 patients with VGI (51.5%) were male. The average age of patients who experienced VGI was 60.9 years (standard deviation, 12.2 years, range, 29-81 years). Preoperative factors that were shown to show statistical significance for the development of VGI were sequential procedures (P = .003), diabetes mellitus (P = .002), hemoglobin A1c more than 7.0 (P = .0002), blood glucose more than 180 mg/dL (P = .0006), and lack of mobility (0.0097). Intraoperative factors associated with VGI were hemostatic agents applied to the surgical field intraoperatively (P = .003) and perioperative hypoxemia (P = .027). Postoperative factors associated with VGI were discharge from the hospital to skilled nursing facility or acute rehabilitation facility (P = .005) and unscheduled clinic visits (P = .008).

CONCLUSION

We measured a 15% incidence of VGI and identified multiple pre-, intra-, and postoperative associated factors. Vigilance is required to prevent VGI and knowledge of specific risk factors is important.

A Multi-Component Strategy to Decrease Wound Complications after Open Infra-Inguinal Re-Vascularization

BACKGROUND

Wound complications remain a significant source of morbidity for patients undergoing open infra-inguinal re-vascularization. The purpose of this study was to determine the impact of several infection-control strategies on post-operative wound complications after open infra-inguinal re-vascularization.

METHODS

A retrospective cohort study was conducted among all patients who underwent an open infra-inguinal re-vascularization procedure before and after 2014. Since 2014, we have implemented strategies to reduce post-operative wound complications, including: (1) Decreasing the use of incisional skin staples, (2) increasing the use of negative pressure wound therapy (NPWT) dressings, and (3) implementing an outpatient elective decontamination protocol for methicillin-resistant Staphylococcus aureus. "Pre-era" is defined as the period between January 2012 and December 2013, before the implementation of infection control strategies; "Post-era" is between January 2015 and August 2016, after implementation. The primary outcome of interest is 30-day wound complications (infection or dehiscence). Multi-variable logistic regression analysis was used to identify significant predictors of wound-related complications between the two cohorts. Propensity score adjustment controlled for baseline patient characteristics, peri-operative variables, and surgeon experience.

RESULTS

A total of 338 open infra-inguinal procedures were performed: 175 in the pre-era and 163 in the post-era. Chlorhexidine skin preparation was used in the majority (321 [95%]) of cases. Comparing the periods, the post-era is characterized by a significant decrease in the use of groin staples (118 [67%] vs. 51 [31%], p < 0.001), and an increased application of NPWT dressings (6 [4%] vs. 66 [43%], p < 0.001). Thirty-five (37%) outpatient elective cases received the pre-operative decontamination protocol in the post-era. Compared with the pre-era, there was a decrease in the 30-day rate of wound complications (68 [39%] to 42 [26%], p = 0.011), and infection-related re-admissions (31 [17.7%] to 21 [12.9%], p = 0.220). When adjusting for patient characteristics, operative variables, and surgeon experience, post-era had significantly lower wound complications (odds ratio [OR] 0.33, p = 0.002) and re-operations (OR 0.16, p = 0.007). Among outpatient elective cases, the decontamination protocol was also independently associated with these two outcomes (wound complications: OR 0.05, p = 0.006; re-operations: 0.06, p = 0.002). The use of groin staples was an independent predictor of deep groin infections (OR 248, p < 0.001) and re-operations (OR 8.16, p = 0.032).

CONCLUSIONS

Wound complications after open infra-inguinal re-vascularization have decreased significantly after the implementation of several infection-control strategies. Findings suggest that skin staples should be avoided in groin wounds, and anti-staphylococcal decontamination protocols decrease wound complications and prevent re-operations.

Cryopreserved Cadaveric Arterial Allograft for Arterial Reconstruction in Patients with Prosthetic Infection

OBJECTIVE

The aim of this study was to report outcomes of cryopreserved arterial allografts used as a vascular substitute in the setting of prosthetic material infection.

METHODS

A retrospective analysis of prospectively collected data was conducted including all consecutive interventions performed with cryopreserved arterial allografts used for vascular reconstruction in the setting of prosthetic material infection between January 2005 and December 2014. Five year outcomes included allograft related re-interventions, survival, primary patency, and limb salvage rates.

RESULTS

Fifty-three procedures were performed using cryopreserved allografts for vascular prosthetic infection: 25 procedures (47%) were performed at aorto-iliac level (Group 1) and 28 procedures (53%) at peripheral level (Group 2). The mean follow-up was 52 months. Five year allograft related re-intervention was 55% in Group 1 (6 allograft ruptures and 5 allograft aneurysm degenerations) and 33% in Group 2 (2 allograft ruptures and 7 allograft aneurysm degenerations). Five year survival was 40% and 68%, primary patency was 89% and 59% and limb salvage was 100% and 89% for Group 1 and 2 respectively.

CONCLUSION

Use of cryopreserved arterial allografts provides acceptable results but is tempered by suboptimal 5 year outcomes with high re-intervention rates.