Predictors of Prosthetic Graft Infection after Infrainguinal Bypass

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.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Femoral-Femoral Bypass for Limb Salvage to Correct Common Iliac Occlusion after Lower Extremity Trauma

BACKGROUND

Roadway injuries are a leading cause of lower extremity vascular trauma. Treating these injuries involves controlling life-threatening hemorrhage and restoring distal perfusion.

MATERIALS AND METHODS

We describe a unique presentation of chronic iliac artery occlusion in the setting of blunt trauma requiring extra-anatomic bypass for maximal limb salvage.

RESULTS

A 50-year-old male presented after a pedestrian versus auto accident. He had mangled bilateral lower extremities and was taken emergently for lower extremity amputations. He was found to have chronic left common iliac occlusion and a femoral-femoral bypass was performed to assist with healing his left below-the-knee amputation.

DISCUSSION

Lack of adequate perfusion can cause poor outcomes in limb salvage. This case demonstrated that lower extremity trauma can be complicated by chronic vascular disease. Reperfusion and adequate wound healing can be accomplished by using bypass grafting after more traditional reperfusion techniques fail.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

TRIAL REGISTRATION

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

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/28759.

Ten Year Experience of Using Cryopreserved Arterial Allografts for Distal Bypass in Critical Limb Ischaemia

OBJECTIVE/BACKGROUND

In critical limb ischaemia (CLI), current guidelines recommend revascularisation whenever possible, preferentially through endovascular means. However, in the case of long occlusions or failed endovascular attempts, distal bypasses still have a place. Single segment great saphenous vein (GSV), which provides the best conduit, is often not available and currently there is no consensus about the best alternative graft.

METHODS

From January 2006 to December 2015, 42 cryopreserved arterial allografts were used for a distal bypass. Autologous GSVs or alternative autologous conduits were unavailable for all patients. The patients were observed for survival, limb salvage, and allograft patency. The results were analysed with Kaplan-Meier graphs.

RESULTS

Estimates of secondary patency at one, two and five years were 81%, 73%, and 57%, respectively. Estimates of primary patency rates at one, two and five years were 60%, 56%, and 26%, respectively. Estimates of limb salvage rates at one, two and five years were 89%, 89%, and 82%, respectively. Estimates of survival rates at one, two and five years were 92%, 76% and 34%, respectively. At 30 days, major amputations and major adverse cardiac events were one and zero, respectively. Six major amputations occurred during the long-term follow up.

CONCLUSION

Despite a low primary patency rate at two years, the secondary patency of arterial allografts is acceptable for distal bypasses. This suggests that cryopreserved arterial allografts are a suitable alternative for limb saving distal bypasses in the absence of venous conduits, improving limb salvage rates and, possibly, quality of life.

Infected Groin (Graft/Patch): Managed with Sartorious Muscle Flap

PURPOSE

The purpose of this study was to review the natural history, clinical outcome and safety in patients undergoing sartorius muscle flap (SMF) for groin infection, including lymphocele.

MATERIALS AND METHODS

We retrospectively reviewed the records of patients who underwent SMF in a single center between 2000 and 2009.

RESULTS

Thirty patients (17 male, 13 female) underwent SMF for groin infection, which included infections of 22 artificial femoral bypass grafts (including 2 cryoveins) and 5 common femoral patch grafts, and 3 lymphocele infections (2 cardiac catheterizations and 1 penile cancer lymph node dissection). Wound isolates were most commonly Gram-positive organisms (n=22) with Gram-negative isolates and mixed infections accounting for 4 and 3 cases, respectively. In 9 patients there was no growth of organisms. Adjunctive wound vacuum-asssisted wound closure therapy was performed in 18 patients. Follow-up duration ranged from 8 days to 56 months (mean 14.1 months) after SMF. Reoperation was performed in 3 patients due to wound bleeding (n=1) and reinfection (n=1). One patient underwent graft excision with external bypass operation. There was 1 mortality case due to sepsis during the study period.

CONCLUSION

We found that muscle flap surgery provides successful single-intervention therapy for groin infections including lymphocele. Graft ligation or aggressive excision with bypass surgery should be reserved for patients requiring rapid control of sepsis for lifesaving.

Predicting the need for muscle flap salvage after open groin vascular procedures: a clinical assessment tool

Groin wound complications after open vascular surgery procedures are common, morbid, and costly. The purpose of this study was to generate a simple, validated, clinically usable risk assessment tool for predicting groin wound morbidity after infra-inguinal vascular surgery. A retrospective review of consecutive patients undergoing groin cutdowns for femoral access between 2005-2011 was performed. Patients necessitating salvage flaps were compared to those who did not, and a stepwise logistic regression was performed and validated using a bootstrap technique. Utilising this analysis, a simplified risk score was developed to predict the risk of developing a wound which would necessitate salvage. A total of 925 patients were included in the study. The salvage flap rate was 11.2% (n = 104). Predictors determined by logistic regression included prior groin surgery (OR = 4.0, p < 0.001), prosthetic graft (OR = 2.7, p < 0.001), coronary artery disease (OR = 1.8, p = 0.019), peripheral arterial disease (OR = 5.0, p < 0.001), and obesity (OR = 1.7, p = 0.039). Based upon the respective logistic coefficients, a simplified scoring system was developed to enable the preoperative risk stratification regarding the likelihood of a significant complication which would require a salvage muscle flap. The c-statistic for the regression demonstrated excellent discrimination at 0.89. This study presents a simple, internally validated risk assessment tool that accurately predicts wound morbidity requiring flap salvage in open groin vascular surgery patients. The preoperatively high-risk patient can be identified and selectively targeted as a candidate for a prophylactic muscle flap.

Results from the International Silver Graft Registry for high-risk patients treated with a metallic-silver impregnated vascular graft

The purpose of this postmarket surveillance registry was to document the efficacy of a vascular prosthesis coated with metallic silver in high-risk patients undergoing vascular reconstructions. Patency (primary endpoint) and freedom from graft infection (secondary endpoint) data were assessed at a minimum of 12 months in patients with significant co-morbidity and/or confirmed graft infections or infected native vessels. Between November 2006 and December 2009, 230 patients with high-risk factors underwent aortic, peripheral and/or extra-anatomic reconstructions with Silver Graft® (SG) in six German, one French and one Polish vascular center. All participating centers used the metallic silver-coated polyester graft (SG) in various diameters and lengths including tubular and bifurcate vascular grafts. Doppler ultrasound follow-ups to determine graft patency were planned at 12 months or done at an earlier time in case the patient became symptomatic. A total of 230 patients were studied. Ten of these 230 patients had graft infections at baseline whereas the remaining 220 subjects had significant risk factors such as coronary artery disease (62.7%, 138/220), vascular access in scar tissue (27.3%, 60/220), Fontaine III/IV (38.2%, 84/220), chronic renal insufficiency (26.8%, 59/220) and diabetes (21.0%, 46/220). The long-term follow-up at 15.5 ± 8.3 months revealed a secondary patency rate of 93.2% (205/220) and an ‘all cause’ mortality rate of 18.6% (41/220). There was a freedom from de novo graft infection rate of 95.9% (211/220) in the high-risk group without graft infections at baseline. One regraft infection occurred distal of the revisional reconstruction in the 10 patients with graft infection at baseline. The presence of perigraft fluid at follow-up and Fontaine III/IV at baseline were found to be predictors for graft patency whereas perigraft fluid presence was the only predictor for de novo graft infections. This registry revealed favorable patency and freedom from de novo infections rates in a ‘high-risk’ population with significant co-morbidities.

Predictors of surgical site infection after open lower extremity revascularization

OBJECTIVES

Surgical site infection (SSI) after open surgery for lower extremity revascularization is a serious complication that may lead to graft infection, prolonged hospitalization, and increased cost. Rates of SSI after revascularization vary widely, with most studies reported from single institutions. The objective of this study was to describe the rate and predictors of SSI after surgery for arterial occlusive disease using national data, and to identify any association between SSI and length of hospital stay, reoperation, graft loss, and mortality.

METHODS

Patients who underwent lower extremity arterial bypass or thromboendarterectomy from 2005-2008 were identified from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) participant use files. Multivariate logistic regression identified predictors of SSI. Odds ratios were adjusted for patient demographics, comorbidities, preoperative laboratory values, and operative factors. The association between SSI and other 30-day outcomes such as mortality and graft failure was determined.

RESULTS

Of 12,330 patients who underwent revascularization, 1367 (11.1%) were diagnosed with an SSI within 30 days. Multivariate predictors of SSI included female gender (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.3-1.6), obesity (OR, 2.1; 95% CI, 1.8-2.4), chronic obstructive pulmonary disease (OR, 1.2; 95% CI, 1.0-1.5), dialysis (OR, 1.5; 95% CI, 1.1-2.1), preoperative hyponatremia (OR, 1.2; 95% CI, 1.0-1.4), and length of operation >4 hours (OR, 1.4; 95% CI, 1.2-1.6). SSI was associated with prolonged (>10 days) hospital stay (OR, 1.8; 95% CI, 1.4-2.1) and higher rates of 30-day graft loss (OR, 2.3; 95% CI, 1.7-3.1) and reoperation (OR, 3.7; 95% CI, 3.1-4.6). SSI was not associated with increased 30-day mortality.

CONCLUSION

SSI is a common complication after open revascularization and is associated with a more than twofold increased risk of early graft loss and reoperation. Several patient and operation-related risk factors that predict postoperative SSI were identified, suggesting that targeted improvements in perioperative care may decrease complications and improve outcomes in this patient population.