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.

Impact of closed-incision negative pressure wound dressings on surgical site infection following groin incisions in vascular surgery; a single-centre experience

OBJECTIVES

Surgical site infection (SSI) is a common complication in vascular surgery, and is associated with increased patient morbidity, readmission and reintervention. The aim of this study was to assess the impact of closed-incision negative pressure wound therapy (CiNPWT) upon rate of SSI and length of hospital stay.

METHODS

This study was reported in line with the STROBE guidelines. We assessed the baseline incidence of SSI from a 12-month retrospective cohort and, following a change in practice intervention with CiNPWT, compared to a 6-month prospective cohort. The primary endpoint was incidence of SSI (according to CDC-NHSN guidelines) while secondary endpoints included length of hospital stay, readmission, reintervention and Days Alive and Out of Hospital (DAOH) to 90-days.

RESULTS

A total of 127 groin incisions were performed: 76 (65 patients) within the retrospective analysis and 51 (42 patients) within the prospective analysis (of whom 69% received CiNPWT). The primary endpoint of SSI was seen in 21.1% of the retrospective cohort and 9.8% of the prospective cohort (p = .099). Readmission was found to be significantly associated with the retrospective cohort (p = .016) while total admission (inclusive of re-admission) was significantly longer in those in the retrospective cohort (p = .013). DAOH-90 was 83 days (77-85) following introduction of the CiNPWT protocol as compared to the retrospective cohort (77 days (64-83), p = .04).

CONCLUSION

Introduction of CiNPWT was associated with a reduced length of hospital stay and improved DAOH-90. Further trials on CINPWT should include patient-centred outcomes and healthcare cost analysis.

Purification of PaTx-II from the Venom of the Australian King Brown Snake and Characterization of Its Antimicrobial and Wound Healing Activities

Infections caused by multi-drug-resistant (MDR) bacteria are a global threat to human health. As venoms are the source of biochemically diverse bioactive proteins and peptides, we investigated the antimicrobial activity and murine skin infection model-based wound healing efficacy of a 13 kDa protein. The active component PaTx-II was isolated from the venom of Pseudechis australis (Australian King Brown or Mulga Snake). PaTx-II inhibited the growth of Gram-positive bacteria in vitro, with moderate potency (MICs of 25 µM) observed against S. aureus, E. aerogenes, and P. vulgaris. The antibiotic activity of PaTx-II was associated with the disruption of membrane integrity, pore formation, and lysis of bacterial cells, as evidenced by scanning and transmission microscopy. However, these effects were not observed with mammalian cells, and PaTx-II exhibited minimal cytotoxicity (CC₅₀ > 1000 µM) toward skin/lung cells. Antimicrobial efficacy was then determined using a murine model of S. aureus skin infection. Topical application of PaTx-II (0.5 mg/kg) cleared S. aureus with concomitant increased vascularization and re-epithelialization, promoting wound healing. As small proteins and peptides can possess immunomodulatory effects to enhance microbial clearance, cytokines and collagen from the wound tissue samples were analyzed by immunoblots and immunoassays. The amounts of type I collagen in PaTx-II-treated sites were elevated compared to the vehicle controls, suggesting a potential role for collagen in facilitating the maturation of the dermal matrix during wound healing. Levels of the proinflammatory cytokines interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2) and interleukin-10 (IL-10), factors known to promote neovascularization, were substantially reduced by PaTx-II treatment. Further studies that characterize the contributions towards efficacy imparted by in vitro antimicrobial and immunomodulatory activity with PaTx-II are warranted.

Systematic Review of Groin Incision Surgical Site Infection Preventative Measures in Vascular Surgery

OBJECTIVE

Groin surgical site infections (SSIs) after open revascularization can lead to devastating consequences in patients. As a result, prevention has been crucial in minimizing the rate of SSIs. This review aims to evaluate the current body of literature regarding prevention techniques including: prophylactic flaps, incision technique, topical antibiotic use, closed-incision negative pressure wound therapy and adhesive drapes METHODS: This review was conducted and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. A systematic review was conducted utilizing the Google Scholar ©, PubMed, and Cochrane Review databases regarding the five prevention topics. The authors identified 1,371 potential studies with 33 studies selected and analyzed after systematic review regarding the five preventative topics.

RESULTS

The primary outcome of interest was how the rate of SSI was affected with each preventative technique. As a result, the recommendations are: - We suggest prophylactic flaps be considered in high-risk surgical patients undergoing open arterial exposure of the groin. [Grade 2C] - We suggest consideration of transverse incisions for open arterial exposure of the groin as a means of SSI prevention. [Grade 2C] - Given the lack of data regarding topical antibiotics no recommendation can be made regarding its use. - We suggest closed-incision negative pressure wound therapy be utilized in groin surgical incisions at high risk for SSI. [Grade 2B] - Given the paucity of data regarding adhesive drapes, such as Ioban ®, no recommendation can be made regarding its use.

CONCLUSIONS

This review highlights the effects of various preventative techniques and their potential benefit in prevention of SSI in the groin. However, there is a glaring deficit in the available data emphasizing the need for additional robust studies to better delineate their effectiveness and implementation into surgical practice. While the use of endovascular techniques continues to increase thus limiting the amount of open arterial procedures and the potential for further studies to be conducted. In order to provide the high-quality studies needed to better evaluate these prevention techniques, large multi-institutional collaboration will likely be necessary to provide the appropriate number of patients to evaluate true effectiveness.

The Contemporary Impact of Body Mass Index on Open Aortic Aneurysm Repair

INTRODUCTION

The Centers for Disease Control and Prevention (CDC) has deemed obesity a national epidemic and contributor to other leading causes of death including heart disease, stroke, and diabetes. Accordingly, the role of body mass index (BMI) and its impact on surgical outcomes has been a focus of persistent investigation. The purpose of this study was to quantify the effect of BMI on open abdominal aortic aneurysm repair (oAAA) outcomes in contemporary practice.

METHODS

All elective oAAAs in the VQI (2010-2021) were identified. End-points included 30-day death, in-hospital complications and 1-year mortality. Patients were stratified into four BMI cohorts (BMI<18.5, 18.5≤BMI<25, 25≤BMI<30, BMI≥30). Spline interpolation was used to explore a potential non-linear association between BMI and perioperative mortality. Mixed-effects Cox regression was used to assess the association between BMI and 1-year survival.

RESULTS

9,479 patients underwent oAAA over the study interval (median age-70, 74%-male, BMI 27±6). Lower BMI patients(<18.5) compared to higher BMI(>30) patients were more likely to be women (53% vs. 32%;p<.0001), current smokers(65% vs. 50%;p<.0001), and have COPD(58% vs. 37%;p<.0001). In contrast, an increased BMI was associated with a greater prevalence of diabetes and CAD (DM-26% vs. 6%;p<.0001; CAD-27% vs. 20%;p=.01). There was no difference in cross-clamp position or visceral/renal bypass between groups, though low BMI patients necessitated more frequent infrainguinal bypass(5% vs. 2%;p=.0002). 30-day mortality and in-hospital complications were greater among low BMI patients(30-day mortality:12% vs. 4%;p<.0001;complications-47% vs. 37%;p<.0001). Interestingly, low BMI conferred a nearly 2-fold increase in observed pulmonary complications(18% vs. 11%;p<.0001). Surgical site infections were twice as common among the lowest and highest BMI groups(4% vs. 2%;p<.0001). 1-year mortality was greatest among low BMI patients(23% vs. 9%;p<.0001). Adjusted spline-fit analysis demonstrated increased mortality among patients with BMI<21 or >34(BMI<18.5-HR 2.1, 95%CI 1.6-2.8;p<.0001; BMI>34-HR 1.3, 95%CI 1.1-1.6;p=.009).

CONCLUSION

Both low (<18.5) and high (>34) BMI were associated with increased oAAA mortality in current practice. Despite the perception that obesity confers substantial surgical risk during oAAA, diminished BMI was associated with a 3-fold increase in 30-day and 1-year mortality. It appears that BMI extremes are distinct proxies for differential clinical phenotypes and should inform risk stratification for oAAA repair.

Effect of climate on surgical site infections and anticipated increases in the United States

Surgical site infections (SSI) are one of the most common and costly hospital-acquired infections in the United States. Meteorological variables such as temperature, humidity, and precipitation may represent a neglected group of risk factors for SSI. Using a national private insurance database, we collected admission and follow-up records for National Healthcare Safety Network-monitored surgical procedures and associated climate conditions from 2007 to 2014. We found that every 10 cm increase of maximum daily precipitation resulted in a 1.09 odds increase in SSI after discharge, while every g/kg unit increase in specific humidity resulted in a 1.03 odds increase in SSI risk after discharge. We identified the Southeast region of the United States at highest risk of climate change-related SSI, with an estimated 3% increase in SSI by 2060 under high emission assumptions. Our results describe the effect of climate on SSI and the potential burden of climate-change related SSI in the United States.

Evaluation of the costing methodology of published studies estimating costs of surgical site infections: A systematic review

OBJECTIVES

Surgical site infections (SSIs) are associated with increased length of hospitalization and costs. Epidemiologists and infection control practitioners, who are in charge of implementing infection control measures, have to assess the quality and relevance of the published SSI cost estimates before using them to support their decisions. In this review, we aimed to determine the distribution and trend of analytical methodologies used to estimate cost of SSIs, to evaluate the quality of costing methods and the transparency of cost estimates, and to assess whether researchers were more inclined to use transferable studies.

METHODS

We searched MEDLINE to identify published studies that estimated costs of SSIs from 2007 to March 2021, determined the analytical methodologies, and evaluated transferability of studies based on 2 evaluation axes. We compared the number of citations by transferability axes.

RESULTS

We included 70 studies in our review. Matching and regression analysis represented 83% of analytical methodologies used without change over time. Most studies adopted a hospital perspective, included inpatient costs, and excluded postdischarge costs (borne by patients, caregivers, and community health services). Few studies had high transferability. Studies with high transferability levels were more likely to be cited.

CONCLUSIONS

Most of the studies used methodologies that control for confounding factors to minimize bias. After the article by Fukuda et al, there was no significant improvement in the transferability of published studies; however, transferable studies became more likely to be cited, indicating increased awareness about fundamentals in costing methodologies.

Single use negative pressure wound therapy in vascular patients: clinical and economic outcomes

OBJECTIVE

Surgical site complications (SSCs) such as dehiscence and infection are a common issue within vascular surgeries and are a key concern to payers and clinicians. It is estimated that occurrence of complications in vascular surgery can increment length of stay by 9.72 days and costs by £3776 per episode. The objective of this research was to determine the clinical and economic impact of the prophylactic use of single use negative pressure wound therapy (sNWPT) in postoperative femoral endarterectomy incisions within a single centre in the Netherlands.

METHOD

Data were extracted retrospectively from the medical notes of patients consecutively treated for femoral endarterectomy between January 2013 and December 2019 in a single centre in the Netherlands. Since August 2016, patients were treated with the sNPWT device and their data were compared with that of patients treated before the introduction of the device. Data were extracted on SSCs and associated healthcare resource use, with comparisons made between the two patient groups.

RESULTS

The study included a cohort of 108 patients. Data of patients treated by standard care (n=64) showed 32 (50%) patients developed complications. This reduced significantly in patients treated with the sNPWT device (n=44) of whom eight (18.2%) developed a postoperative complication (p=0.0011). Average postoperative costs per patient were €3119 for those in the standard care group and €2630 where the sNPWT device was used.

CONCLUSION

sNPWT provided clinical and economic benefits over standard care in the treatment of femoral endarterectomy patients, significantly reducing rate of complication and their associated costs.

Cryopreservation moderates the thrombogenicity of arterial allografts during storage

INTRODUCTION

Management of vascular infections represents a major challenge in vascular surgery. The use of cryopreserved vascular allografts could be a feasible therapeutic option, but the optimal conditions for their production and use are not precisely defined.

AIMS

To evaluate the effects of cryopreservation and the duration of storage on the thrombogenicity of femoral artery allografts.

METHODS

In our prospective study, eleven multi-organ-donation-harvested human femoral arteries were examined at five time points during storage at -80°C: before cryopreservation as a fresh native sample and immediately, one, twelve and twenty-four weeks after the cryopreservation. Cross-sections of allografts were perfused with heparin-anticoagulated blood at shear-rates relevant to medium-sized arteries. The deposited platelets and fibrin were immunostained. The thrombogenicity of the intima, media and adventitia layers of the artery grafts was assessed quantitatively from the relative area covered by fibrin- and platelet-related fluorescent signal in the confocal micrographs.

RESULTS

Regression analysis of the fibrin and platelet coverage in the course of the 24-week storage excluded the possibility for increase in the graft thrombogenicity in the course of time and supported the hypothesis for a descending trend in fibrin generation and platelet deposition on the arterial wall. The fibrin deposition in the cryopreserved samples did not exceed the level detected in any of the three layers of the native graft. However, an early (up to week 12) shift above the native sample level was observed in the platelet adhesion to the media.

CONCLUSIONS

The hemostatic potential of cryopreserved arterial allografts was retained, whereas their thrombogenic potential declined during the 6-month storage. The only transient prothrombotic change was observed in the media layer, where the platelet deposition exceeded that of the fresh native grafts in the initial twelve weeks after cryopreservation, suggesting a potential clinical benefit from antiplatelet therapy in this time-window.

Benefit of Negative Pressure Dressings in Vascular Surgery Patients with Infra-Inguinal 1 Incisions after short-term followupAssessing the Benefit of Incisional Negative Pressure 2 Dressings in Community-Based Vascular Surgery Patients with Infra-Inguinal Incisions

OBJECTIVES

Within the vascular patient population there is increased risk of developing wound complications especially in infra-inguinal incisions. There has been increasing interest in using closed incisional negative pressure dressings to decrease the risk of wound complications. To assess the efficacy of these incisional wound dressings we studied surgical site infections and seroma rates of infrainguinal incisions in our vascular patient population.

METHODS

This was a multi-institutional, retrospective study from July 2015- June 2019. In 2017 our institution began using the Prevena incisional wound system. Wound complication rates were compared to the non Prevena group prior to 2017. There was a total of 100 infrainguinal incisions (left and right combined) that received the Prevena wound system and 138 infrainguinal incisions that had not. The primary endpoint was to assess for wound complication rates including surgical site infections and seroma formation. Surgical site infections were graded based on the ACS-NSQIP SSI criteria. Seroma formation was diagnosed based on clinical diagnosis, imaging studies (ultrasound, CT) or needle aspiration of fluid collection.

RESULTS

Analysis showed a statistically significant decrease in the rate of SSIs in the Prevena group when compared to the non Prevena group (p=0.012). There was no statistical difference between the two groups in the rate of seroma formation (p=0.155). Of the 100 incisions that received the Prevena wound system 1.2% (1/82) had a femoral SSI and 22% (4/18) had a popliteal SSI. For seroma formation 24.4% (20/82) had a femoral seroma and 11.1% (2/18) had a popliteal seroma. Of the 138 incisions that did not have the Prevena wound system, 9.6% (10/104) had a femoral SSI, and 8.8% (3/34) had a popliteal SSI. For seroma formation 24.0% (25/104) had a femoral seroma and 8.8% (3/34) had a popliteal seroma. Comorbid conditions were assessed in the two study groups and there was no statistical significance regarding rates of surgical site infections between the groups.

CONCLUSIONS

The use of an incisional negative pressure dressing decreases the rate of surgical site infections in infrainguinal incisions. Regarding the use of these wound systems for seromas; our study did not show a statistical significance in decreasing seroma rates.

Longitudinal versus transverse incision for common femoral artery exposure: a systematic review and meta-analysis

BACKGROUND

A longitudinal or a transverse incision is routinely used for common femoral artery (CFA) exposure. Some believe a transverse incision is associated with a lower incidence of postoperative complications. We performed a systematic review and meta-analysis to evaluate the risk of postoperative surgical site infection, lymphatic complications, wound dehiscence and haematoma formation when using a longitudinal or transverse incision for CFA exposure.

METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines were adhered to. We searched various databases such as MEDLINE via PubMed and Embase for relevant studies from inception till 31 May 2020. Relevant search terms such as 'longitudinal', 'transverse', 'vertical', 'horizontal', 'femoral', 'incision' were used. We included both randomized controlled trials and case-controlled studies, and extracted data related to study characteristics and postoperative complications. We assessed risk of bias using the Cochrane risk of bias tool and the Newcastle-Ottawa scale. A random-effects meta-analysis was performed to obtain the pooled proportions and risk ratios (RR) for our study outcomes.

RESULTS

We included seven studies with a total of 5922 groin incisions. A longitudinal incision was associated with a significantly higher incidence of wound infection (RR 2.93, 95% confidence interval (CI) 1.12-7.70, P = 0.03) and wound dehiscence (RR 2.87, 95% CI 1.06-7.77, P = 0.04). The risk of lymphatic complications (RR 1.09, 95% CI 0.39-3.05, P = 0.87) and wound haematoma (RR 2.85, 95% CI 0.88-9.21, P = 0.08) were similar.

CONCLUSIONS

A longitudinal incision may be associated with a higher incidence of wound infection and wound dehiscence, as compared to using a transverse incision for CFA exposure.

Cost-effectiveness analysis of negative pressure wound therapy dressings after open inguinal vascular surgery - The randomised INVIPS-Trial

AIM

While the scientific evidence in favour of negative pressure wound therapy (NPWT) dressings on sutured incisions in the prevention of surgical site infections (SSIs) has increased, the cost-effectiveness after vascular surgery has not been evaluated. The aim of this study was to evaluate the cost-effectiveness of NPWT compared to standard dressings for the prevention of SSIs after open inguinal vascular surgery.

MATERIALS AND METHODS

Patient data were retrieved from the randomised INVIPS-trial's open arm, which included patients randomised to either NPWT or standard dressings. The patients were surveyed for SSIs for 90 days postoperatively. The patients' individual cost data were included and analysed from a healthcare perspective. The patients' quality of life was measured using the Vascuqol-6 questionnaire pre- and 30 days postoperatively. Cost-effectiveness of NPWT was determined by decreased or equal total costs and a significant reduction in SSI incidence.

RESULTS

The mean vascular procedure-related costs at 90 days were €16,621 for patients treated with NPWT (n = 59) and €16,285 for patients treated with standard dressings (n = 60), p = 0.85. The SSI incidence in patients treated with NPWT was 11.9% (n = 7/59) compared to 30.0% (n = 18/60) with standard dressings, p = 0.015. This corresponds to an increased mean cost of €1,853 per SSI avoided. The cost-effectiveness plane of incremental vascular procedure-related costs and difference in Vascuqol-6 score showed that 42% of estimates were in the quadrant where NPWT was dominant.

CONCLUSION

NPWT is considered cost-effective over standard dressings in patients undergoing open inguinal vascular surgery due to reduced SSI incidence at no higher costs.

Management of Vascular Infections in Low- and Middle-Income Countries

Background: Vascular infections are rare and challenging conditions with significant deaths and morbidity. Their management necessitates a multi-disciplinary approach and substantial human and financial resources. The management selected may be influenced by the available resources in low- and middle-income countries (LMICs), where such resources may be variable. Methods: We reviewed the published literature and reviewed the management options for various vascular infections with a focus on carotid, aortic, infrainguinal, and dialysis access infections. Results: Recommendations related to prevention and treatment will be offered from the perspective of LMICs. The general principles for prevention are in compliance with established surgical site infection guidelines and minimize the use of prosthetic material. Early detection and intervention by removing all infected prosthetic material, debridement, drainage, and coverage of the infected field with vascularized tissue are essential steps in the management of the infection. Revascularization using an extra-anatomic or in situ approach is individualized based on the resources and expertise available. Conclusions: The prevention and management of vascular infections in LMICs are effective by adhering to time-proven principles even with limited resources.

American College of Surgeons National Surgical Quality Improvement Program as a Quality Improvement Tool: A Single Institution's Experience with Vascular Surgical Site Infections

Vascular surgical site infections (VSSIs) result in significant patient morbidity and hospital cost. The objective of this study is to report a single hospital's experience using the National Surgical Quality Improvement Program (NSQIP) as an instrument to decrease VSSIs. After review of initial NSQIP data, changes in antibiotic dosage and timing, surgical preparation, patient warming, and oxygenation were put into practice. Records of all patients undergoing vascular surgical operations during a two-year period were reviewed and VSSIs were identified. Statistical comparisons were made between groups before and after implementation of these changes. A total of 478 cases met our criteria. Practice changes were introduced in October 2009 and fully implemented by January 2010. Two hundred forty-three cases were performed in 2009 and 235 in 2010. When operations during the two time periods were compared, significantly fewer VSSIs were identified in 2010 than in 2009 ( P = 0.036). NSQIP enabled our institution to identify an unacceptably high level of VSSIs. By implementing changes in our clinical practice, we were able to significantly lower our rate of VSSI.

Inadequate Perioperative Prophylaxis and Postsurgical Complications After Graft Implantation Are Important Risk Factors for Subsequent Vascular Graft Infections: Prospective Results From the Vascular Graft Infection Cohort Study

BACKGROUND

Reconstructive vascular surgery has become increasingly common. Vascular graft infections (VGIs) are serious complications, leading to increased morbidity and mortality. Previously described risk factors for VGIs include groin incisions, wound infections, and comorbidities. We aimed to identify modifiable predictors for VGIs as targets for infection prevention strategies.

METHODS

Participants of the prospective Vascular Graft Infection Cohort (VASGRA) with surgery between 2013 and 2017 were included. The observation time was calculated from surgery until a confirmed VGI or the last follow-up. Variables were assessed by infection status, using non-parametric tests. Univariable and multivariable Cox proportional hazard regression models, adjusted for demographic factors, were applied to assess risk factors for a VGI.

RESULTS

A total of 438 predominantly male (83.1%) patients with a median age of 71 years (interquartile range [IQR] 63 - 76) contributed to 554 person years of follow-up. Thereof, 39 (8.9%) developed a VGI, amounting to an incidence rate of 7.0/100 person years. We found incisional surgical site infections (adjusted hazard ratio [aHR] 10.09, 95% CI 2.88 - 35.34); hemorrhage (aHR 4.92, 1.28-18.94); renal insufficiency (aHR 4.85, 1.20 - 19.61); inadequate perioperative prophylaxis in patients with an established antibiotic treatment, compared to the additional application of perioperative prophylaxis (aHR 2.87, 95% CI 1.17 - 7.05); and procedure time increases of 1-hour intervals (aHR 1.22, 95% CI 1.08 - 1.39) to be risk factors for VGIs.

CONCLUSIONS

We identified procedure time; inadequate perioperative prophylaxis, especially among patients with an established antibiotic treatment; and several postsurgical infectious and non-infectious complications as modifiable, predictive factors for VGIs and, therefore, as keys to improved surveillance programs and prevention strategies.

CLINICAL TRIALS REGISTRATION

NCT01821664.

Surgical site infection and costs in low- and middle-income countries: A systematic review of the economic burden

BACKGROUND

Surgical site infection (SSI) is a worldwide problem which has morbidity, mortality and financial consequences. The incidence rate of SSI is high in Low- and Middle-Income countries (LMICs) compared to high income countries, and the costly surgical complication can raise the potential risk of financial catastrophe.

OBJECTIVE

The aim of the study is to critically appraise studies on the cost of SSI in a range of LMIC studies and compare these estimates with a reference standard of high income European studies who have explored similar SSI costs.

METHODS

A systematic review was undertaken using searches of two electronic databases, EMBASE and MEDLINE In-Process & Other Non-Indexed Citations, up to February 2019. Study characteristics, comparator group, methods and results were extracted by using a standard template.

RESULTS

Studies from 15 LMIC and 16 European countries were identified and reviewed in full. The additional cost of SSI range (presented in 2017 international dollars) was similar in the LMIC ($174-$29,610) and European countries ($21-$34,000). Huge study design heterogeneity was encountered across the two settings.

DISCUSSION

SSIs were revealed to have a significant cost burden in both LMICs and High Income Countries in Europe. The magnitude of the costs depends on the SSI definition used, severity of SSI, patient population, choice of comparator, hospital setting, and cost items included. Differences in study design affected the comparability across studies. There is need for multicentre studies with standardized data collection methods to capture relevant costs and consequences of the infection across income settings.

Herpes wound infection after femoral endarterectomy

Wound infection after common femoral endarterectomy is a well-documented phenomenon leading to significant morbidity, especially in the setting of a prosthetic graft. A push has recently been made in the literature for salvage of the prosthetic graft using debridement, antibiotics, and vacuum-assisted closure therapy. Herein we present the case of wound infection after common femoral endarterectomy with bovine patch angioplasty initially presumed to be of bacterial origin that failed to respond to vacuum-assisted closure therapy until the viral nature of the pathogen was discovered. The patient will continue lifelong valacyclovir for suppressive therapy.

Deep Learning-Based Risk Model for Best Management of Closed Groin Incisions After Vascular Surgery

BACKGROUND

Reduced surgical site infection (SSI) rates have been reported with use of closed incision negative pressure therapy (ciNPT) in high-risk patients.

METHODS

A deep learning-based, risk-based prediction model was developed from a large national database of 72,435 patients who received infrainguinal vascular surgeries involving upper thigh/groin incisions. Patient demographics, histories, laboratory values, and other variables were inputs to the multilayered, adaptive model. The model was then retrospectively applied to a prospectively tracked single hospital data set of 370 similar patients undergoing vascular surgery, with ciNPT or control dressings applied over the closed incision at the surgeon's discretion. Objective predictive risk scores were generated for each patient and used to categorize patients as "high" or "low" predicted risk for SSI.

RESULTS

Actual institutional cohort SSI rates were 10/148 (6.8%) and 28/134 (20.9%) for high-risk ciNPT versus control, respectively (P < 0.001), and 3/31 (9.7%) and 5/57 (8.8%) for low-risk ciNPT versus control, respectively (P = 0.99). Application of the model to the institutional cohort suggested that 205/370 (55.4%) patients were matched with their appropriate intervention over closed surgical incision (high risk with ciNPT or low risk with control), and 165/370 (44.6%) were inappropriately matched. With the model applied to the cohort, the predicted SSI rate with perfect utilization would be 27/370 (7.3%), versus 12.4% actual rate, with estimated cost savings of $231-$458 per patient.

CONCLUSIONS

Compared with a subjective practice strategy, an objective risk-based strategy using prediction software may be associated with superior results in optimizing SSI rates and costs after vascular surgery.

Outcome of rectus femoris muscle flaps for groin coverage after vascular surgery

OBJECTIVE

The aim of this retrospective cohort study was to investigate the outcome of rectus femoris muscle flaps (RFFs) for deep groin wound complications in vascular surgery patients and to compare the outcome with a cohort of sartorius muscle flaps (SMFs) because the RFF is a promising alternative technique for groin coverage.

METHODS

All RFFs and SMFs performed by vascular surgeons in a regional collaboration in The Southern Netherlands were retrospectively reviewed. Primary outcomes were muscle flap survival, overall and secondary graft salvage, and limb salvage. Secondary outcomes were 30-day groin wound complications and mortality, donor site and vascular complications, 1-year amputation-free survival, overall patient survival, impaired knee extensor function, and length of hospital stay.

RESULTS

A total of 96 RFFs were performed in 88 patients (mean age, 68 years; 67% male) and compared with a cohort of 30 SMFs in 28 patients (mean age, 64 years; 77% male). At a mean follow-up of 29 months and 23 months, respectively, comparable flap survival (94% vs 90%), secondary graft salvage (80% vs 92%), and limb salvage (89% vs 90%) rates were found. The 30-day mortality rates were 12% and 17%, respectively, and the 1-year amputation-free survival was comparable between treatment groups (71% vs 68%).

CONCLUSIONS

This study presents a large series of RFFs for deep groin wound complications after vascular surgery. We demonstrate that muscle flap coverage using the rectus femoris muscle by vascular surgeons is an effective way to manage complex groin wound infections in a challenging group of patients, achieving similarly good results as the SMF.

[Thigh muscle flaps for postoperative inguinal wound complications in vascular surgery : Sartorius muscle versus rectus femoris muscle]

BACKGROUND

Inguinal wound complications often cause postoperative morbidity and also mortality following vascular surgical interventions. The aim of this study was to report experiences and a comparison of the outcomes using rectus femoris muscle flaps (RFF) and sartorius muscle flaps (SMF).

MATERIAL AND METHODS

A retrospective study was performed at two locations of a cross-border vascular center and all muscle flap interventions performed at the two centers within the vascular surgery department were reviewed. Primary outcomes were muscle flap survival, graft salvage and major amputations.

RESULTS

A total of 44 RFFs were performed in 39 patients (mean age 67 years, 73% males) and 25 SMFs in 24 patients (mean age 64 years, 76% males). Wound infections were the most common indications for muscle flap reconstruction. At a mean follow-up of 24 months (±24) and 17 months (±20), respectively, comparable flap survival rates (91% vs. 84%), wound healing rates (72% vs. 83%), graft salvage (65% vs. 73%) and amputation rates (9% vs. 8%) were found.

CONCLUSION

Muscle flap reconstruction is an effective way to cover groin defects resulting from deep wound infections after vascular surgery, achieving good results in a high-risk group of patients. No differences were found between SMF and RFF regarding amputation and graft loss. Both techniques can be safely performed, depending on the preference and experience of the surgical team. The RFF technique should be preferentially used to cover large tissue defects, whereas the SMF procedure can be preferred to cover smaller defects in the groin.

Incisional negative pressure wound therapy for the prevention of surgical site infection after open lower limb revascularization - Rationale and design of a multi-center randomized controlled trial

Introduction

Lower limb revascularization with inguinal incisions is a common vascular surgical procedure. Due to risk of injury to lymphatic vessels and a diverse bacterial flora in the groin, surgical site infections (SSI) represent a common and sometimes life-threatening complication. While transverse incisions in endovascular aneurysm repair has a low SSI rate, vertical incisions in thrombendarterectomy (TEA) has a higher risk and bypass the highest risk. This randomized controlled trial (RCT) will investigate the protective role of negative pressure wound therapy (NPWT) on closed inguinal incisions in elective vascular surgery undergoing TEA and bypass procedures, respectively, to prevent SSI.

Methods

This RCT registered at ClinicalTrials.gov (Identifier: NCT01913132) compares the effects of a NPWT dressing (PICO™, Smith & Nephew, UK) to standard wound dressing on postoperative SSI. The multi-center study includes two distinct vascular procedures with different SSI risk profiles: TEA and lower limb bypass. Three hundred and fifty-eight groin incisions are anticipated to be included in the TEA group and 133 inguinal incisions in the bypass group. Bilateral inguinal incisions will be randomized to NPWT in one groin and control dressing in the contralateral groin, and this dependency was accounted for in sample size calculation and will be addressed in data analysis.

Discussion

This RCT attempts to evaluate the potential benefit of NPWT on closed inguinal incisions after two distinct vascular procedures at high risk of SSI. Outcome of this trial could have implications on postoperative wound care in both vascular and non-vascular surgical patients.

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.

Meta-analysis of negative pressure wound therapy of closed groin incisions in arterial surgery

BACKGROUND

Surgical-site infection (SSI) after groin incisions for arterial surgery is common and may lead to amputation or death. Incisional negative pressure wound therapy (NPWT) dressings have been suggested to reduce SSIs. The aim of this systematic review with meta-analysis was to assess the effects of incisional NPWT on the incidence of SSI in closed groin incisions after arterial surgery.

METHODS

A study protocol for this systematic review of RCTs was published in Prospero (CRD42018090298) a priori, with predefined search, inclusion and exclusion criteria. The records generated by the systematic research were screened for relevance by title and abstract and in full text by two of the authors independently. The selected articles were rated for bias according to the Cochrane risk-of-bias tool.

RESULTS

Among 1567 records generated by the search, seven RCTs were identified, including 1049 incisions. Meta-analysis showed a reduction in SSI with incisional NPWT (odds ratio (OR) 0·35, 95 per cent c.i. 0·24 to 0·50; P < 0·001). The heterogeneity between the included studies was low (I²  = 0 per cent). The quality of evidence was graded as moderate. Two studies had multiple domains in the Cochrane risk-of-bias tool rated as high risk of bias. A subgroup meta-analysis of three studies of lower limb revascularization procedures only (363 incisions) demonstrated a similar reduction in SSI (OR 0·37, 0·22 to 0·63; P < 0·001; I²  = 0 per cent).

CONCLUSION

Incisional NPWT after groin incisions for arterial surgery reduced the incidence of SSI compared with standard wound dressings. The risk of bias highlighted the need for a high-quality RCT with cost-effectiveness analysis.

Defining Types and Determining Risk Factors for Vascular Surgery Readmissions

BACKGROUND

Vascular surgery patients typically have numerous comorbidities, which puts them at higher risk for postoperative readmissions. This study aims to investigate the risk factors for and appropriately categorize the various types of vascular surgery readmissions.

METHODS

Nine hundred seventy-two patients were retrospectively reviewed. Readmissions were classified into 3 separate groups: readmissions that occurred between 0 and 30 days (30-day readmissions), 31-90 days (3-month readmissions), and 91-365 days (1-year readmissions). Each readmission was then assigned to 1 of the 4 categories based on whether they were related to the index procedure and whether they were planned. Univariate tests were performed for demographic variables based on their type of readmission, and logistic regressions were then performed to identify predictors of each unplanned, related readmissions.

RESULTS

The overall 30-day readmission rate was 21.9% (n = 213). The unplanned, related readmission cohort (n = 83) had the highest readmission rate of 8.5%. The related, planned readmission rate was 5.9% (n = 58), while the unrelated, unplanned readmission rate was 5.6% (n = 55). In contrast, the overall 1-year readmission rate was 40.0% (n = 389), with the largest category being unplanned, unrelated readmissions at 19.7% (n = 191). The unplanned, related readmission rate was 8.7% (n = 85), whereas the planned, related readmission rate was 5.7% (n = 55). Compared with other types of readmissions, unplanned, related readmissions tended to affect patients who were younger, had poor glycemic control, and had higher body mass indexes (BMIs). Multivariate predictors of unplanned, related readmissions were poor glycemic control at 3 months (odds ratio [OR]: 2.16, P = 0.03), and BMI at 30 days (OR: 1.06, P = 0.04) and 1 year (OR: 1.05, P = 0.04).

CONCLUSIONS

Readmissions have varying risk factors depending on their category; targeting glycemic control and obesity may reduce unplanned, related readmissions.

The role of FDG PET/CT in therapy control of aortic graft infection

PURPOSE

¹⁸F-FDG PET/CT (PET/CT) is a useful tool for the diagnosis of aortic graft infection (AGI), but has rarely been used to influence therapeutic decisions during follow-up. We aimed to study the role of PET/CT in the long-term monitoring of patients.

METHODS

Participants of the prospective Vascular Graft Infection Cohort Study (VASGRA) were included if they had microbiologically proven AGI. We quantified the metabolic activity in PET/CT by using maximum standardized uptake value (SUV_max) and further classified it as being focal or diffuse. Multivariable linear regression models were fit using generalized estimating equations to investigate factors associated with SUV_max over time.

RESULTS

Sixty-eight participants with AGI contributed to 266 PET/CTs including 36 examinations performed after stop of antimicrobial therapy. Higher C-reactive protein (CRP) (adjusted coefficient per log₁₀ mg/L 0.05 [95% C.I. 0.02-0.08]) was associated with higher SUV_max. CRP, metabolic and clinical findings informed the decision to either start (medians of SUV_max 7.1 and CRP 31.5 mg/L; 100% focal uptake), escalate (SUV_max 9.5; CRP 31.5; 100% focal uptake), continue (SUV_max 6.0; CRP 9.95 mg/L; 90% focal uptake), or stop (SUV_max 4.3; CRP 3.5 mg/L; 61% focal uptake) antibiotic treatment. Of note, decisions to escalate or continue antibiotic treatment were taken despite normal CRP values in 12.5 and 35.7% of PET/CTs, respectively.

CONCLUSIONS

Consecutive PET/CTs could influence the clinical decision-making in patients with AGI in the near future. More studies on the use of PET/CT in case of aortic graft infection may offer the potential for individualized treatment approaches. CLINICALTRIALS.

GOV IDENTIFIER

NCT01821664.

Evaluation of inguinal vascular surgical scars treated with closed incisional negative pressure wound therapy using three-dimensional digital imaging-A randomized controlled trial on bilateral incisions

PURPOSE OF THE INVESTIGATION

Scar formation is an important, permanent surrogate marker for wound healing. The main aim of this randomized trial was to evaluate the effects of incisional negative pressure wound therapy (iNPWT) on scar formation in uncomplicated wound healing with 3-dimensional (3D) digital imaging.

BASIC PROCEDURES

Patients undergoing bilateral inguinal incisions after vascular surgery were randomized to receive iNPWT and standard dressing on separate sides. The incisional scars were documented at a median time of 808 days (range 394-1194) after surgery with 3D photography, which were objectively evaluated by two plastic surgeons using the Stony Brook scar evaluation scale (SBSES) and a 10-point graded numeric ranking scale (NRS10). Subjective evaluation was performed with the patient observer scar assessment scale (POSAS). Patients with surgical site infection or other wound complications were excluded to minimize bias. The p-values were calculated using McNemar's and Wilcoxon signed-rank test for paired nominal and paired continuous data, respectively.

MAIN FINDINGS

Among 33 patients, 32 patients had undergone endovascular aortic repair (EVAR) and 31 patients had transverse inguinal incisions. Objective and subjective scar evaluation showed no difference between iNPWT and standard dressing. In objective scorings, 18.8 and 21.9% received the highest possible SBSES total score in the iNPWT and standard dressing groups, while 43.8 and 37.5% received the highest possible NRS10 score, respectively. The inter-rater reliability between the two assessors for SBSES total score and NRS10 showed an intra-class correlation (ICC) of 0.78 and 0.68 for NPWT and 0.70 and 0.77 for traditional dressing, respectively.

PRINCIPAL CONCLUSION

The present randomized trial showed that iNPWT and standard dressings on closed transverse inguinal incisions after EVAR resulted in equal subtle scar formation. Objective scar evaluation with 3D images showed good inter-rater agreement.

Body mass index as a predictor of outcome in total knee replace: A systemic review and meta-analysis

BACKGROUND

To conduct a meta-analysis with randomized controlled trials (RCTs) published in full text to demonstrate database to show the associations of perioperative, postoperative outcomes of normal and high body mass index (BMI) to provide the predictive diagnosis for clinic.

METHODS

Literature search was performed in PubMed, Embase, Web of Science and Cochrane Library for information from the earliest date of data collection to February. RCTs comparing the benefits and risks of normal BMI with those of high BMI in primary total knee arthroplasty (TKA) were included. Statistical heterogeneity was quantitatively evaluated by X2 test with the significance set P<0.10 or I2>50%.

RESULTS

Seven RCTs consisting of 33,778 patients were included. (6065 normal BMI patient; 27,713 high BMI). The results showed that high BMI was related to a greater increase in operative time, post-operative range of motion (ROM), post-operative Knee Society and function scores (KSS), infection rate (P<0.1). No differences in pulmonary embolism and perioperative mortality rates were found between normal and high body mass index patients with follow-up≥5years (P>0.1).

CONCLUSIONS

Compared with normal BMI patients, high BMI patients demonstrated an increased risk of perioperative and postoperative complications and clear difference about complications between normal and high BMI about TKA.

Phenylephrine infusion impact on surgical site infections after lower extremity bypass surgery

OBJECTIVE

Lower extremity bypass (LEB) operations have high rates of surgical site infections (SSI). Phenylephrine is a commonly used vasoconstrictor which may reduce skin blood flow and increase the likelihood of SSI in these patients. We studied the potential effect of phenylephrine infusion during LEB surgery on SSI.

METHODS

LEB cases and their demographic data were identified through the Vascular Quality Initiative registry. SSI in this population was identified using the hospital epidemiology surveillance database. Phenylephrine use in this population was identified through chart review.

RESULTS

We identified 699 patients who underwent LEB; 82 (11.7%) developed an SSI, and 244 of 698 (35.0%) were treated with phenylephrine infusion. In bivariate analysis, higher body mass index (28.8 kg/m² vs 27.3 kg/m²; P = .034), diabetes (14.6% vs 9.4%; P = .035), hypertension (12.6% vs 4.7%; P = .038), groin incision (13.2 vs 5.4%; P = .013) and longer procedure times (17.1% for >220 minutes and 8.9% for ≤220 minutes; P = .003) were associated with higher rates of SSI. Whereas phenylephrine infusion exhibited a trend toward a higher rate (14.8% vs 9.9%; P = .057). In the logistic regression model, diabetes (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.0-3.2; P = .032), total procedure time (OR, 1.85; 95% CI, 1.1-3.1; P = .026) and vertical groin incision (OR, 2.6; 95% CI, 1.1-6.5; P = .035) were independent predictors of increased SSI rates, whereas body mass index (OR, 1.04; 95% CI, 0.99-1.08; P = .09), hypertension (OR, 2.5; 95% CI, 0.6-10.9; P = .22), and phenylephrine infusion (OR, 1.08; 95% CI, 0.63-1.85; P = .78) were not independent predictors of increased SSI rates.

CONCLUSIONS

Phenylephrine infusion did not increase the risk of SSI in patients who underwent LEB.

Axillobifemoral Bypasses: Reappraisal of an Extra-Anatomic Bypass by Analysis of Results and Prognostic Factors

BACKGROUND

Axillobifemoral bypass (AFB) is method of second choice. It is reserved for patients at high operative risk or to bypass infected vessels or grafts. In this study, we analyzed prognostic factors for AFB patency and limb salvage rate to facilitate the choice of procedure.

METHODS

Between Jan 2006 and Aug 2013, 45 patients underwent AFB surgery in our department, 24 for critical limb ischemia (CLI) and 23 for infection. Endpoints of study were graft occlusion, graft infection, amputation and patient's death. Prognostic factors were compared by univariate analysis for each indication group. Mean follow-up was 40.2 (±23.2) months.

RESULTS

Complication rate was significantly higher in infection group (88.0 vs. 54.4%, p = 0.003) and in emergency surgery (83.3 vs. 56.9%, p = 0.023). Overall primary patency rate after AFB procedures was 66.7% after 1, 3, and 5 years, while secondary patency rate was 91.1% after 1 year, 82.2% after 3 years and 80.0% after 5 years. The primary and secondary patency rates did not significantly differ between the both groups (p = 0.059 and p = 0.136). Following prognostic factors showed a statistically significant influence on patency rates in CLI group: >1 previous vascular surgical intervention, patch angioplasty at the distal anastomosis site, complications after previous vascular surgery, and perioperative intake of platelet aggregation inhibitor. Only the employed bypass material had a statistical significant influence on the secondary patency rates in the infection group. Overall limb salvage rate was 82.2% after 1 year, 80.0% after 3 years and 77.8% after 5 years. There were statistically significant differences in the limb salvage rates depending on emergency surgery and a 3-vessel-run-off in the lower leg in both indication groups.

CONCLUSION

AFB have acceptable patency and limb salvage rates. AFB is a good alternative in patients with CLI at high operative risk or with infections of aortoiliac segments, even with endovascular approaches. They remain essential tools in vascular surgeon's repertoire.

Negative-pressure wound therapy for prevention and treatment of surgical-site infections after vascular surgery

BACKGROUND

Indications for negative-pressure wound therapy (NPWT) in vascular surgical patients are expanding. The aim of this review was to outline the evidence for NPWT on open and closed wounds.

METHODS

A PubMed, EMBASE and Cochrane Library search from 2007 to June 2016 was performed combining the medical subject headings terms 'wound infection', 'abdominal aortic aneurysm (AAA)', 'fasciotomy', 'vascular surgery' and 'NPWT' or 'VAC'.

RESULTS

NPWT of open infected groin wounds was associated with shorter duration of wound healing by 47 days, and was more cost-effective than alginate dressings in one RCT. In one RCT and six observational studies, NPWT-related major bleeding and graft preservation rates were 0-10 and 83-100 per cent respectively. One retrospective comparative study showed greater wound size reduction per day, fewer dressing changes, quicker wound closure and shorter hospital stay with NPWT compared with gauze dressings for lower leg fasciotomy. NPWT and mesh-mediated fascial traction after AAA repair and open abdomen was associated with high primary fascial closure rates (96-100 per cent) and low risk of graft infection (0-7 per cent). One retrospective comparative study showed a significant reduction in surgical-site infection, from 30 per cent with standard wound care to 6 per cent with closed incisional NPWT.

CONCLUSION

NPWT has a central role in open and infected wounds after vascular surgery; the results of prophylactic care of closed incisions are promising.

Local perivascular adiponectin associates with lower extremity vascular operative wound complications

BACKGROUND

Wound complication rates after lower extremity vascular operative procedures stand as high as 40% and represent a major cause of morbidity, mortality, and cost. In view of increasing recognition of adipose tissue involvement in homeostasis and the response to injury, we hypothesized that adipose phenotype is linked to operative wound outcomes.

METHODS

Clinical history, peripheral blood, and subcutaneous and perivascular adipose tissue were prospectively collected at the time of operation in patients undergoing lower extremity revascularization and lower extremity amputations. Nine biologic mediators (adiponectin; interleukin [IL]-1β, IL-6, and IL-8; leptin; monocyte chemoattractant protein-1; plasminogen activator inhibitor-1; resistin; and tumor necrosis factor) were assayed in the adipose tissues and plasma. The 30-day wound complications were captured in real time. Logarithmic transformation of mediator levels was performed based on positively skewed, non-Gaussian distribution, and data were compared using the Student t test. Bonferroni correction was used for multiple comparisons.

RESULTS

Sixty-six patients undergoing lower extremity revascularization or lower extremity amputations for severe peripheral arterial disease were enrolled. The 30-day follow-up was 92.4%. In total, 19 (29%) patients developed wound complications. Patients who developed wound complications had elevated perivascular adiponectin levels (mean ± standard error, 2,372.45 ± 648.64 ng/mL vs 832.53 ± 180.54 ng/mL, P = .004). Perivascular IL-1β levels were lower among patients with wound dehiscence (0.41 ± 0.004 pg/mL vs 0.73 ± 0.09 pg/mL, P = .001).

CONCLUSION

Local adipose tissue mediator levels at the time of operation demonstrate a previously undescribed compartment-specific relationship to wound outcomes in patients undergoing lower extremity vascular operative procedures. These associations provide fertile directives for defining the mechanisms underlying the pathogenesis of wound complications and their prevention.

Interaction of obesity and infections

There is evidence that certain infections may induce obesity. Obese persons may also have more severe infections and have compromised response to therapies. The objective of this study is to review the available literature identifying infections that potentially contribute to greater body mass index (BMI) and differential responses of overweight and obese persons to infections. A systematic literature review of human studies examining associations between infections and weight gain, differential susceptibility, severity, and response to prevention and treatment of infection according to BMI status (January 1980-July 2014) was conducted. Three hundred and forty-three studies were eligible for inclusion. Evidence indicated that viral infection by human adenovirus Ad36 and antibiotic eradication of Helicobacter pylori were followed by weight gain. People who were overweight or obese had higher susceptibility to developing post-surgical infections, H1N1 influenza and periodontal disease. More severe infections tended to be present in people with a larger BMI. People with a higher BMI had a reduced response to vaccinations and antimicrobial drugs. Higher doses of antibiotics were more effective in obese patients. Infections may influence BMI, and BMI status may influence response to certain infections, as well as to preventive and treatment measures. These observations have potential clinical implications.

Negative pressure wound therapy for high-risk wounds in lower extremity revascularization: study protocol for a randomized controlled trial

Background

Rates of surgical site infections (SSIs) following groin incision for femoral artery exposure are much higher than expected of a clean operation. The morbidity and mortality is high, particularly with the use of prosthetic grafts. The vascular surgery population is at an increased risk of SSIs related to peripheral vascular disease (PVD), diabetes, obesity, previous surgery and presence of tissue loss. Negative pressure wound therapy (NPWT) dressings have been used on primarily closed incisions to reduce surgical site infections in other surgical disciplines. We have not come across any randomized controlled trials to support the prophylactic use of negative pressure wound therapy in high-risk vascular patients undergoing lower limb revascularization.

Methods/design

In this single-center, prospective randomized controlled trial, patients scheduled for a lower limb revascularization requiring open femoral artery exposure who are at a high risk (BMI > 30 kg/m², previous femoral cutdown or Rutherford V or VI category for chronic limb ischemia) will be eligible for the study. A total of 108 groin incisions will be randomized to the use of a negative pressure wound device or standard adhesive gauze dressing. Patients will be followed in hospital and reassessed within the first 30 days postoperatively. The primary outcome is SSI within the first 30 days of surgery and will be determined using the intention-to-treat principle. Secondary outcomes include length of stay, emergency room visits, reoperation, amputation and mortality. A cost analysis will be performed.

Discussion

The trial is expected to define the role of NPWT in SSI prophylaxis for lower limb revascularization in high-risk vascular patients. The results of the study will be used to inform current best practice for perioperative care and the minimization of SSIs.

Trial registration

NCT02084017, March 2014

A randomised study of NPWT closure versus alginate dressings in peri-vascular groin infections: quality of life, pain and cost

OBJECTIVE

The aim of this study was to compare the vacuum assisted wound closure (VAC) system (negative pressure wound therapy; NPWT) and alginate wound dressings in terms of quality of life (QoL), pain resource use and cost in patients with deep peri-vascular groin infection after vascular surgery.

METHOD

Patients with deep peri-vascular groin infection (Szilagyi grade III) were included and randomised to NPWT or alginate therapy. EuroQol 5D (EQ-5D) and brief pain inventory (BPI) were used to evaluate QoL and pain, respectively.

RESULTS

Wound healing time until complete skin epithelialisation was shorter in the NPWT (n=9) compared to the alginate group (n=7), median 57 and 104 days, respectively (p=0.026). No difference was recorded in QoL and pain between the groups at study start and the second assessment. QoL analysis within groups between time points, showed that patients in NPWT groups improved in EQ-5D domains, 'self-care' (p= 0.034), 'usual activities' (p=0.046); EQ-5D index value (p=0.046) and EQ-VAS (p=0.028). Patients in the NPWT group reported significantly less pain 'affecting their relations with other people' and 'sleep' between time points. The NPWT group had significantly fewer dressing changes compared to the alginate group (p<0.001). The median frequency of wound dressing changes outside hospital was 20 (IQR 6-29) in the NPWT group (n=9), compared to 48 (IQR 42-77) in the alginate group (n=8; p=0.004). The saved personnel time for wound care in the first week for the NPWT group, compared with the alginate group, was 4.5 hours per week per nurse. The total hospitalised care cost was 83-87% of the total cost in both groups.

CONCLUSION

NPWT therapy in patients with deep peri-vascular groin infection can be regarded as the dominant strategy due to improved clinical outcome with equal cost and quality of life measures.

Antibiotic Prophylaxis in Autologous Vein Graft Reconstructions of the Lower Extremity

BACKGROUND

Different factors contribute to infection after arterial reconstructive surgery. Prophylactic antibiotic use during surgery is widespread, however, there is insufficient evidence to support the use of prophylactic antibiotics with autologous vein grafting. The aim of our study was to assess the effect of single-dose prophylactic antibiotics in patients undergoing autologous vein grafting.

METHODS

Patients undergoing arterial bypass reconstruction in the lower extremity between 2004 and 2012 were retrospectively screened for use of vein grafts. Patients receiving single-dose antibiotic prophylaxis (group 1) were compared with those not receiving prophylaxis (group 2).

RESULTS

Primary outcome was surgical site infection (SSI), and 142 patients were included. The SSI occurred in 22% of patients in group 1 and in 29% of patients in group 2 (P = .39; odds ratio: 1.46 confidence interval 95%: 0.61-3.47).

CONCLUSIONS

Results showed no significant effect from single-dose antibiotic prophylaxis on lowering the incidence of SSI.

Prospective, randomized, multi-institutional clinical trial of a silver alginate dressing to reduce lower extremity vascular surgery wound complications

OBJECTIVE

Wound complications negatively affect outcomes of lower extremity arterial reconstruction. By way of an investigator initiated clinical trial, we tested the hypothesis that a silver-eluting alginate topical surgical dressing would lower wound complication rates in patients undergoing open arterial procedures in the lower extremity.

METHODS

The study block-randomized 500 patients at three institutions to standard gauze or silver alginate dressings placed over incisions after leg arterial surgery. This original operating room dressing remained until gross soiling, clinical need to remove, or postoperative day 3, whichever was first. Subsequent care was at the provider's discretion. The primary end point was 30-day wound complication incidence generally based on National Surgical Quality Improvement Program guidelines. Demographic, clinical, quality of life, and economic end points were also collected. Wound closure was at the surgeon's discretion.

RESULTS

Participants (72% male) were 84% white, 45% were diabetic, 41% had critical limb ischemia, and 32% had claudication (with aneurysm, bypass revision, other). The overall 30-day wound complication incidence was 30%, with superficial surgical site infection as the most common. In intent-to-treat analysis, silver alginate had no effect on wound complications. Multivariable analysis showed that Coumadin (Bristol-Myers Squibb, Princeton, NJ; odds ratio [OR], 1.72; 95% confidence interval [CI], 1.03-2.87; P = .03), higher body mass index (OR, 1.05; 95% CI, 1.01-1.09; P = .01), and the use of no conduit/material (OR, 0.12; 95% CI, 0.82-3.59; P < .001) were independently associated with wound complications.

CONCLUSIONS

The incidence of wound complications remains high in contemporary open lower extremity arterial surgery. Under the study conditions, a silver-eluting alginate dressing showed no effect on the incidence of wound complications.