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

Effectiveness of Negative Pressure Wound Therapy on Groin Surgical Site Infection After Lower Extremity Bypass for Chronic Limb-Threatening Ischemia

BACKGROUND

Surgical site infections (SSIs) are a common cause of patient morbidity, hospital readmission, and reoperation after lower extremity bypass (LEBs) surgery for chronic limb-threatening ischemia (CLTI). Recent studies on the use of incisional negative pressure wound therapy (NPWT) in LEB surgery have reported conflicting results. In this single-center study, we examined our experience on the impact of NPWT on groin SSI rates after LEB surgery.

METHODS

We retrospectively queried electronic medical records for all LEB operations performed for CLTI. Multivariate logistic regression analysis was used to identify risk factors associated with postoperative SSI. Using these risk factors, subset analysis was performed to determine whether NPWT was associated with reduced SSI in high-risk patients.

RESULTS

From 2018 to 2022, a total of 367 patients underwent LEB surgery for CLTI. Mean patient age was 66 years. Postoperative groin SSI was diagnosed in 22.9% (n = 84) of patients. Patients suffering SSI were more frequently morbidly obese (6.0% vs 1.8%, P = 0.03) and had higher rates of chronic obstructive pulmonary disease (35.7% vs 23.3%, P = 0.02). Other comorbidities and demographic data were similar between groups. NPWT was utilized in 19.6% (n = 72) of patients, with no baseline differences between SSI and no SSI cohorts (15.5% vs 20.9%, P = 0.28). On multivariate analysis, female sex (odds ratio [OR] 1.88, 95% confidence interval [CI] 1.06-3.35, P = 0.03), white race (OR 2.17, 95% CI 1.23-3.82, P = 0.007), morbid obesity (OR 3.67, 95% CI 0.93-14.4, P = 0.05), and active smoking (OR 4.07, 95% CI 1.20-13.8, P = 0.02) were independently associated with postoperative SSI. Subset analysis among patients at increased risk of SSI did not reveal any differences in wound infection with NPWT usage.

CONCLUSIONS

In our experience, NPWT does not appear to be more effective than standard dressings in preventing groin SSI after LEB surgery for CLTI, even among populations at heightened risk for wound infection.

Characterizing Early-Onset Surgical Site Infection After Lower Extremity Bypass Surgery

BACKGROUND

Surgical site infections (SSI) are the most common complication following lower extremity bypass (LEB) surgery. SSIs contribute to significant patient morbidity and healthcare expenditure, and accurate detection of SSIs remains an important step in reduction efforts. In this study, we aimed to characterize early-onset SSIs among patients undergoing LEB surgery.

METHODS

Institutional medical records were retrospectively queried for all LEB operations performed across 3 hospitals from 2018 to 2022. All SSIs within a 90-day postoperative period were included, per CDC definition, and categorized as early- (within 7 days of operation), standard- (8-30 days), or delayed-onset (31-90 days). The Southampton grading scale was used to stratify the severity of infection (grade 2, erythema; grade 3, erythema with serous drainage; grade 4; erythema with purulent drainage; or grade 5, severe wound necrosis). Data were analyzed using univariate tests and logistic regression analysis.

RESULTS

A total of 517 LEB operations were performed over the 5-year study period. Median follow-up period was 18.5 months. Early-, standard-, and delayed-onset SSIs were diagnosed in 2.9% (n = 15), 15.1% (n = 78), and 4.6% (n = 24) of the patients, respectively. Compared with standard- and delayed-onset groups, patients with early-onset SSIs were more frequently nonsmokers (26.7% vs. 3.9% vs. 8.3%, P = 0.03) and had lower prevalence of comorbidities. Early-onset SSIs most frequently presented as Southampton grade 2 (60.0%) or grade 5 (20.0%) infections, whereas standard- and delayed-onset SSIs were more evenly distributed among grade 2 (30.4%), grade 3 (41.2%), and grade 4 (21.6%) presentations (P = 0.002). The most commonly isolated organisms among the early-onset SSI group were Gram-negative rods (20.0%). In comparison, polymicrobial infections (19.6%) and Gram-positive cocci (14.7%) were most common among standard- and delayed-onset groups (P = 0.04). The early-onset SSI group experienced a longer index hospitalization (11 vs. 6 vs. 8 days, P = 0.02) and lower 30-day readmission rates (13.3% vs. 59.0% vs. 45.8%, P = 0.005) compared with standard- and delayed-onset groups. On multivariate analysis, active smoking (hazard ratio [HR] 0.15, 95% confidence interval [CI], 0.02-0.98, P = 0.035), former smoking (HR 0.08, 95% CI, 0.01-0.71, P = 0.02), coronary artery disease (HR 0.15, 95% CI, 0.03-0.83, P = 0.03), and hypertension (HR 0.13, 95% CI, 0.03-0.68, P = 0.02) were associated with a lower risk of early-onset infection, when compared with patients suffering standard- and delayed-onset SSIs.

CONCLUSIONS

Early-onset SSIs after LEB surgery have a distinct clinical presentation, impact healthier patients, and are associated with more virulent organisms compared with standard- and delayed-onset SSIs.

Staged versus nonstaged elective hybrid iliofemoral revascularization - analysis of ten years of prospective data

BACKGROUND

Reports of large series of hybrid iliofemoral revascularization for chronic lower limb ischemia are scarce. The aims of this study were to evaluate outcomes for staged and nonstaged procedures, and to evaluate risk factors for outcomes at 90 days.

METHODS

Patients were consecutively included between 2013 and 2023. Surgical site infection (SSI) was defined by the ASEPSIS criteria and major adverse limb events (MALE) as onset of acute or continuing or worsening chronic limb ischemia or major amputation. Factors associated with outcomes were tested in a multivariable logistic regression analysis and expressed in odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

Patients undergoing nonstaged procedures (n = 124) had higher Trans-Atlantic Inter-Society Consensus (TASC) class representing anatomical occlusive complexity, more often through-and through femoral guidewire access, more endoprosthesis, more covered stents, longer procedure time with open groin wounds, and less contralateral femoral access, than those undergoing staged procedures (n = 31). The median time interval between the staged procedures was 1 day, and iliac stenting was done first in 77%. The median in-hospital stay was nonsignificantly longer in staged procedure (8 vs. 6 days, P = 0.053). The overall SSI and MALE rates were 25.8% and 20.0%, respectively, without differences between groups. Diabetes mellitus (OR 3.7, 95% CI 1.2-7.2]) and presence of a foot ulcer (OR 3.7, 95% CI [1.5-9.4]) were independently associated with MALE at 90 days. Postoperative hyperglycemia was nonsignificantly associated with SSI (OR 2.1 (95% CI 1.0-4.5), P = 0.066) in multivariable analysis.

CONCLUSIONS

The risks of SSI and MALE after elective hybrid iliofemoral revascularization were high. There appears to be no benefit in performing staged as opposed to nonstaged procedures. The extent of iliofemoral occlusive disease according to the TASC classification had little influence on outcomes whereas diabetes mellitus and presence of a foot ulcer had greater impact on MALE.

The effectiveness of waxing or epilation compared to conventional methods of hair removal in reducing the incidence of surgical site infections: a systematic review and meta-analysis

Background

Surgical site infections (SSIs) pose a significant challenge to healthcare systems by elevating patient morbidity and mortality and driving up financial costs. Preoperative skin preparation is crucial for preventing SSIs; however, certain traditional methods of hair removal have been found to increase the risk of SSI development. Mechanical epilation and waxing constitute two relatively explored methods of hair removal, which may hold potential to accelerate wound healing due to the activation of stem cells within hair follicles. This review assesses the efficacy of preoperative hair removal via waxing and mechanical epilation in reducing SSI incidence.

Methods

This systematic review was prospectively registered with PROSPERO (ref: CRD42023423798) and a protocol previously published in a peer-reviewed journal. All findings are reported according to PRISMA guidelines. A comprehensive search of Medline, Embase, CENTRAL, ClinicalTrials.gov and CINAHL. Inclusion criteria encompassed adult patients undergoing any surgical procedure, comparing waxing or epilation against other hair removal methods or no hair removal, with SSI incidence as the primary outcome. There was no restriction on study size or quality to ensure a comprehensive literature evaluation.

Results

The review found no studies meeting the selection criteria out of 576 records screened.

Discussion/conclusion

This review has identified no literature regarding the use of waxing and mechanical epilation as methods of preoperative hair removal. The lack of experimental evidence combined with the potential physiological advantages of these techniques indicate that this could be a valuable area of future research. These techniques may represent novel approaches to SSI prevention, particularly beneficial in high-risk surgical disciplines like vascular surgery.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=423798, PROSPERO (CRD42023423798).

Impact of Wound Closure Technique on Surgical Site Infection After Lower Extremity Bypass Surgery

BACKGROUND

Surgical site infections (SSIs) are among the most common complications after lower extremity bypass (LEB). Both patient and hospital-related factors have been associated with SSI after LEB; however, the impact of surgical closure technique on SSI incidence remains unclear.

METHODS

Institutional electronic medical records (EMRs) were retrospectively queried for all LEB procedures performed from 2018 to 2022. Data were collected on patient demographics, medical comorbidities, operative details, wound closure techniques, and postoperative outcomes. Closure techniques included skin staples, absorbable monofilament (Monocryl), nonabsorbable monofilament (Nylon), or left open to heal by secondary intention. Logistic regression analysis was utilized to identify risk factors and calculate adjusted odds ratios (ORs) for postoperative SSI.

RESULTS

A total of 517 patients underwent LEB surgery over the study period. SSI was diagnosed in 120 (23.2%) patients over a median follow-up period of 1.5 years. The most common SSI locations were groin incision (40.0%), saphenectomy (31.7%), and leg incision (19.2%). The median onset of SSI was 18.5 d (interquartile range [IQR] 11-28 d) post-LEB surgery. Patients with SSI had higher body mass index (BMI) (28.2 [IQR 24.2-33.5] vs. 26.6 [23.1-31.5] kg/m2, P = 0.03) compared with non-SSI patients. Patient age, sex, and medical comorbidities were otherwise similar between groups. There were no differences in closure technique (79.2% vs. 78.1% staples, 18.3% vs. 19.7% Monocryl, 0.8% vs. 1.8% Nylon, 1.7% vs. 0.5% open; P = 0.53) in SSI versus non-SSI groups. On multivariate analysis, patient BMI (OR 1.04 per unit, 95% confidence interval [CI] 1.01-1.08, P = 0.02), reoperative field (OR 1.81, 95% CI 1.00-3.25, P = 0.03), and active smoking (OR 2.72, 95% CI 1.12-6.59, P = 0.048) were independently associated with increased SSI incidence. Postoperative SSI resulted in prolonged hospital length of stay (LOS) (7 vs. 6 days, P = 0.04), unplanned hospital readmission (49.2% vs. 12.3%, P < 0.001), and reoperation rates (64.7% vs. 8.1%, P < 0.001). Bypass graft infection rates were also higher among patients suffering postoperative SSI (9.2% vs. 0.0%, P < 0.001). On subset analysis of patients at increased risk of postoperative SSI, as found on multivariate modeling, there were no differences in closure technique between SSI and no SSI groups.

CONCLUSIONS

This study provides insights on wound closure techniques and postoperative SSI made available through granular, operative data that are not found in large database analyses. Surgical wound closure technique was not associated with postoperative SSI after LEB surgery, even among patients at increased risk of infection. These data support individualization of wound closure techniques among patients undergoing LEB surgery.

A systematic review and meta-analysis of outcomes associated with development of surgical site infection after lower-limb revascularization surgery

OBJECTIVES

Although surgical site infection (SSI) is a commonly used quality metric after lower-limb revascularization surgery, outcomes associated with development of this complication are poorly characterized. We conducted a systematic review and meta-analysis of studies reporting associations between development of an SSI after these procedures and clinical outcomes and healthcare resource use.

METHODS

We searched MEDLINE, Embase, CENTRAL, and Evidence-Based Medicine Reviews (inception to April 4th, 2023) for studies examining adjusted associations between development of an SSI after lower-limb revascularization surgery and clinical outcomes and healthcare resource use. Two investigators independently screened abstracts and full-text citations, extracted data, and assessed risk of bias. Data were pooled using random-effects models. Heterogeneity was assessed using I2 statistics. GRADE was used to assess estimate certainty.

RESULTS

Among 6671 citations identified, we included 11 studies (n = 61,628 total patients) that reported adjusted-associations between development of an SSI and 13 different outcomes. Developing an SSI was associated with an increased adjusted-risk of hospital readmission (pooled adjusted-risk ratio (aRR) = 3.55; 95% CI (confidence interval) = 1.40-8.97; n = 4 studies; n = 13,532 patients; I2 = 99.0%; moderate certainty), bypass graft thrombosis within 30-days (pooled aRR = 2.09; 95% CI = 1.41-3.09; n = 2 studies; n = 23,240 patients; I2 = 51.1%; low certainty), reoperation (pooled aRR = 2.69; 95% CI = 2.67-2.72; n = 2 studies; n = 23,240 patients; I2 = 0.0%; moderate certainty), bleeding requiring a transfusion or secondary procedure (aRR = 1.40; 95% CI = 1.26-1.55; n = 1 study; n = 10,910 patients; low certainty), myocardial infarction or stroke (aRR = 1.21; 95% CI = 1.02-1.43; n = 1 study; n = 10,910 patients; low certainty), and major (i.e., above-ankle) amputation (pooled aRR = 1.93; 95% CI = 1.26-2.95; n = 4 studies; n = 32,859 patients; I2 = 83.0; low certainty). Development of an SSI >30-days after the index operation (aRR = 2.20; 95% CI = 1.16-4.17; n = 3 studies; n = 21,949 patients; low certainty) and prosthetic graft infection (aRR = 6.72; 95% CI = 3.21-12.70; n = 1 study; n = 272 patients; low certainty) were both associated with an increased adjusted-risk of major amputation. Prosthetic graft infection was also associated with an increased adjusted-risk of mortality >30-days after the index procedure (aRR = 6.40; 95% CI = 3.32-12.36; n = 1 study; n = 272 patients; low certainty).

CONCLUSIONS

This systematic review and meta-analysis suggests that development of an SSI after lower-limb revascularization surgery significantly increases patient morbidity and healthcare resource use. SSI is therefore a valuable quality metric after these surgeries. However, current estimates are based on heterogenous, low-to-moderate certainty evidence and should be confirmed by large, multicenter, cohort studies.

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.

Effectiveness of Closed Incision Negative Pressure Wound Therapy for Infrainguinal Bypass in the Vascular Quality Initiative

BACKGROUND

To analyze surgical site infections (SSIs) after infrainguinal bypass for standard dressings versus closed incision negative pressure wound therapy (ciNPWT) in the Society for Vascular Surgery's Vascular Quality Initiative (VQI).

METHODS

We retrospectively analyzed SSI after infrainguinal bypass procedures in the VQI from December 2019 to December 2021 comparing ciNPWT and standard dressings. The primary outcome of any superficial or deep wound infection at 30 days was analyzed in a subset of procedures with 30-day follow-up data (cohort A, n = 1,575). Secondary outcomes including in-hospital SSI, return to the operating room (OR) for infection, and length of stay (LOS) were analyzed for all procedures (cohort B, n = 9,288). Outcomes were analyzed in propensity-matched cohorts.

RESULTS

Patients who received ciNPWT (n = 1,389) were more likely to be female (34% vs. 32%, P = 0.04) with a higher rate of smoking history (90% vs. 86%, P = 0.003), diabetes (54% vs. 50%, P = 0.007), obesity (34% vs. 26%, P < 0.001), prior peripheral vascular intervention (57% vs. 51%, P < 0.001), and to prosthetic conduit (55% vs. 48%, P < 0.001) compared to patients with standard dressings (n = 7,899). After propensity matching of cohort A (n = 1,256), the 30-day SSI rate was 4% (12/341) in the ciNPWT and 6% (54/896) in the standard dressing group (P = 0.07, 95% CI 0.03-1.06). In the propensity-matched in-hospital cohort B (n = 5,435), SSI was 3% (35/1,371) in the ciNPWT group and 2% (95/4,064) in the standard dressing group (P = 0.66). There was no difference in the rate of return to the OR for infection, 1% (36/4,064) vs. 1% (19/1,371) (P = 0.13) or LOS, 9.0 vs. 9.0 days (P = 0.86) for the standard versus ciNPWT groups.

CONCLUSIONS

In this analysis of the VQI registry, the use of ciNPWT after infrainguinal bypass did not result in a statistically significant decrease in 30-day SSI. We recommend that surgeons consider the use of ciNPWT as part of a bundled process of care for high risk rather than all patients, as it may reduce SSI after infrainguinal bypass.

Risk Analysis and Clinical Outcomes in Chronic Limb-threatening Ischemia Patients with Surgical Site Infection after Distal Bypass

BACKGROUND

A recent randomized control study showed that long-term outcomes after surgical revascularization were superior to those after endovascular treatment for cases with chronic limb-threatening ischemia (CLTI) with an appropriate single-segment great saphenous vein. However, surgical site infection (SSI) in CLTI cases after infrapoplital bypass also resulted in a prolonged hospital stay and poor outcomes, including graft disruption. The aim of the current study was to analyze risk factors for SSI in CLTI patients after distal bypass and to compare outcomes in patients with and without SSI.

METHODS

A total of 515 cases that underwent distal bypass at a single center between 2009 and 2022 were analyzed retrospectively. Comparisons were made between patients with and without SSI after distal bypass. The primary end point was limb salvage after distal bypass.

RESULTS

Of the 515 cases that underwent distal bypass, 79 (15%) had SSI. The risk factors for SSI were preoperative antibacterial drug use (P = 0.001), pedal bypass (P = 0.001), and prolonged operation time (≥150 min) (P = 0.010). The median hospital stay in SSI cases was longer than that in non-SSI cases (P < 0.001). Of 515 distal bypasses, 7 (1.3%) bypass grafts ruptured postoperatively due to SSI, and of these 7 cases, 6 ruptured during the day, 5 cases occurred within 1 month postoperatively, and 2 patients (29%) are alive without amputation. The mean follow-up period was 34 ± 30 months. During follow-up, 62 limbs (SSI cases, 19; non-SSI cases, 43) required major amputation and there were 234 deaths (SSI cases, 46; non-SSI cases, 188). The 1-, 3-, and 5-year limb salvage rates of 82%, 71%, and 62%, respectively, in SSI cases were significantly lower than those in non-SSI cases (P < 0.001). The 5-year survival rate of 29% in SSI cases showed a tendency to be lower than that in non-SSI cases (P = 0.058).

CONCLUSIONS

The limb salvage rate in SSI cases was lower than in non-SSI cases after distal bypass. Graft rupture due to SSI occurred at a rate of 1.3% and resulted in poor outcomes in most cases. SSIs adversely affect outcomes and further study is needed to identify methods to avoid SSI following distal bypass.

Investigation of center-specific saphenous vein utilization rates in femoral popliteal artery bypass and associated impact of conduit on outcomes

OBJECTIVE

The purpose of this study is to investigate variation in great saphenous vein (GSV) use among the various centers participating in the Vascular Quality Initiative infrainguinal bypass modules. Further, differences in outcomes in femoral-popliteal artery bypass with single segment GSV conduit vs prosthetic conduit will be documented. Center GSV use rate impact on outcomes will be investigated.

METHODS

Primary exclusions were patients undergoing redo bypass, urgent or emergent bypass, and those in whom prosthetic graft was used while having undergone prior coronary artery bypass grafting. The distribution of GSV use across the 260 centers participating in Vascular Quality Initiative infrainguinal bypass module was placed into histogram and variance in mean GSV use evaluated with analysis of variance analysis. Centers that used GSV in >50% of bypasses were categorized as high use centers and centers that used the GSV in <30% of cases were categorized as low use centers. Baseline differences in patient characteristics and comorbidities in those undergoing bypass with GSV vs prosthetic conduit were analyzed with χ2 testing and the Student t test, as were those undergoing treatment in high vs low use centers. Multivariable time-dependent Cox regression analyses were then performed for the primary outcomes of major amputation ipsilateral to the operative side and mortality in long-term follow-up. High vs low use center was a dichotomous variable in these regressions. Secondary outcomes of freedom from graft infection and freedom from loss of primary patency were performed with Kaplan-Meier analysis.

RESULTS

Among centers with >50 patients meeting inclusion criteria for this study, GSV use ranged from 15% to 93% (analysis of variance P < .001). When considering all centers irrespective of number of patients, the range was 0% to 100%. On Kaplan-Meier analysis, GSV conduit use was associated with improved freedom from loss of primary or primary assisted patency, improved freedom from major amputation after index hospitalization, improved freedom from graft infection after the index hospitalization, and improved freedom from mortality in long-term follow-up (log-rank P < .001 for all four outcomes). Both low use center (hazard ratio, 1.35; P < .001) and prosthetic graft use (hazard ratio, 1.24; P < .001) achieved multivariable significance as risks for mortality in long-term follow-up. Other variables with a multivariable mortality association are presented in the manuscript. Low use center and prosthetic bypass were significant univariable but not multivariable risks for major amputation after index hospitalization.

CONCLUSIONS

There is remarkably wide variation in GSV use for femoral popliteal artery bypass among various medical centers. GSV use is associated with enhanced long-term survival as well as freedom from loss of bypass patency and graft infection. The data herein indicate institutional patterns of prosthetic conduit choice, which has the potential to be altered to enhance outcomes.