Index complications predict secondary complications after infrainguinal lower extremity bypass for critical limb ischemia

A Meta-Analysis to Derive Population-Based Quality Benchmarks of the Incidence of Surgical Site Infection after Lower Limb Revascularization Surgery

BACKGROUND

The reported incidence of surgical site infection (SSI) after lower limb revascularization surgery varies. We conducted a systematic review and meta-analysis of population-based studies reporting the incidence of SSI in adults who underwent these surgeries in high-income countries to derive SSI quality benchmarks.

METHODS

We searched MEDLINE, EMBASE, CENTRAL, and Evidence-Based Medicine Reviews (inception-to-April 28th, 2022) for population-based studies estimating the cumulative incidence of SSI among adults who underwent lower limb revascularization surgery for peripheral artery disease (PAD) in high-income countries. Two investigators independently screened abstracts and full-text articles, extracted data, and assessed risks of bias. We used random-effects models to pool data and GRADE to assess certainty.

RESULTS

Among 6,258 citations, we included 53 studies (n = 757,726 patients); 8 of which (n = 435,769 patients) reported nonoverlapping data that were meta-analyzed. The pooled cumulative incidence of any SSI was 6.0 in 100 patients [95% confidence interval (CI) = 4.3-8.0 in 100 patients; n = 8 studies; n = 435,769 patients; moderate certainty]. The cumulative incidence of Szilagyi grade I (cellulitis), grade II (subcutaneous tissue), and grade III (prosthetic graft) SSI was 6.5 in 100 patients (95% CI = 4.3-8.6 in 100 patients; n = 2 studies; n = 39,645 patients; low certainty), 2.1 in 100 patients (95% CI = 2.0-2.3 in 100 patients; n = 2 studies; low certainty), and 0.4 in 100 patients (95% CI = 0.4-0.4 in 100 patients; n = 1 study; n = 333,275 patients; low certainty), respectively. The pooled cumulative incidence of any early (in-hospital/≤30-days) and late (>30-days) SSI was 6.2 in 100 patients (95% CI = 4.4-8.0 in 100 patients; n = 7 studies; n = 431,273 patients; moderate certainty) and 3.7 in 100 patients (95% CI = 2.2-5.2 in 100 patients; n = 2 studies; n = 10,565 patients; low certainty), respectively.

CONCLUSIONS

This systematic review derived population-based benchmarks of the incidence of any SSI; Szilagyi I, II, and III SSI; and early and late SSI after lower limb revascularization surgery. These may be used by practicing surgeons and healthcare leaders/administrators to guide quality improvement efforts in the United States and perhaps other countries.

American Society of Anesthesiologists-Physical Status Classification As An Independent Risk Factor of Surgical Site Infection After Infra-Inguinal Arterial Bypass

OBJECTIVES

The present study aimed to assess whether high-risk American Society of Anesthesiologists (ASA)-Physical Status was an independent risk factor for the development of surgical site infection (SSI) after infra-inguinal lower extremity bypass (LEB).

SUMMARY OF BACKGROUND DATA

The ASA-Physical Status Classification System assesses the overall physical status preoperatively. ASA-Physical Status is associated with postoperative morbidity and mortality. However, limited data are available on how ASA-Physical Status Class affects the development of SSI after infra-inguinal LEB.

METHODS

Patients who had undergone infra-inguinal LEB from January 1, 2015 to December 31, 2018, for obliterative arteriopathy or popliteal aneurysm at our university hospital were included. SSI risk factors were identified using multivariable logistic regression. The length of hospital stay, major limb events (MALE), major adverse cardiovascular events (MACE), and all-cause mortality were compared for patients with SSI versus those without SSI 3 months and 1- year of follow-up after the index surgery.

RESULTS

Among the 267 patients included, 30 (11.2%) developed SSI during the 3-month period and 32 (12%) at 1 year. ASA-Physical Status ≥3 [odds ratio (OR): 3.7, 95% confidence interval CI) 1.5-11.1], emergency surgery (OR: 2.7, 95% CI 1.2-6.0), general anesthesia (OR: 2.8, 95% CI 1.3-6.1), and procedure performed by a junior surgeon (OR: 2.7, 95% CI 1.3-6.0) were independently associated with SSI. At 3 months and 1 year, SSI was significantly associated with MALE (including surgical wound debridement, subsequent thrombectomy, major amputation), length of hospital stay, and all-cause mortality.

CONCLUSION

The ASA-Physical Status should be considered in medical management when an infra-inguinal LEB is considered in frail patients, to prevent surgical complications.

Construction and evaluation of networks among multiple postoperative complications

BACKGROUND AND OBJECTIVE

Postoperative complications confer an increased risk of reoperation, prolonged length of hospital stay, and increased mortality. Many studies have attempted to identify the complex associations among complications to preemptively interrupt their progression, but few studies have looked at complications as a whole to reveal and quantify their possible trajectories of progression. The main objective of this study was to construct and quantify the association network among multiple postoperative complications from a comprehensive perspective to elucidate the possible evolution trajectories.

METHODS

In this study, a Bayesian network model was proposed to analyze the associations among 15 complications. Prior evidence and score-based hill-climbing algorithms were used to build the structure. The severity of complications was graded according to their connection to death, with the association between them quantified using conditional probabilities. The data of surgical inpatients used in this study were collected from four regionally representative academic/teaching hospitals in a prospective cohort study in China.

RESULTS

In the network obtained, 15 nodes represented complications or death, and 35 arcs with arrows represented the directly dependent relationship between them. With three grades classified on that basis, the correlation coefficients of complications within grades increased with increased grade, ranging from -0.11 to -0.06, 0.16, and 0.21 to 0.4 in grade 1 to grade 3, respectively. Moreover, the probability of each complication in the network increased with the occurrence of any other complication, even mild complications. Most seriously, once cardiac arrest requiring cardiopulmonary resuscitation occurs, the probability of death will be up to 88.1%.

CONCLUSIONS

The present evolving network can facilitate the identification of strong associations among specific complications and provides a basis for the development of targeted measures to prevent further deterioration in high-risk patients.

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.

Association between index complication and outcomes after inpatient pediatric surgery

PURPOSE

A cascade of complications is believed to be the primary mechanism underlying failure to rescue (FTR), or death of a patient after a postoperative complication. It is unknown whether specific types of index complications are associated with the incidence of secondary complications and FTR after pediatric surgery.

METHODS

National cohort study of patients within the National Surgical Quality Improvement Program-Pediatric database who underwent inpatient surgery (2012-2019). Index complications were grouped into nine categories (cardiovascular, venous thromboembolism, pulmonary, bleeding/transfusion, renal, central nervous system, wound, infectious, or minor [defined as having an associated mortality rate <1%]). The association between the type of index complication with FTR, secondary complications, reoperation, unplanned readmission, and postoperative length of stay was evaluated with multivariable logistic regression and generalized linear modeling.

RESULTS

Among 425,386 patients, 15.5% had at least one complication, 16.6% had one or more secondary complications, 13.9% reoperation, 14.5% readmission, and 2.4% FTR.  Secondary complication (10.8-59.7%) and FTR (0.3-31.1%) rates varied by type of index complication. Relative to patients who had an index minor complication, those with an index infectious complication were most likely to have secondary complication (Odds Ratio [OR] 10.3, 95% CI [9.36-11.4]). Index CV complications were most strongly associated with FTR (OR 30.7 [24.0-39.4]). Index wound complications had the greatest association with reoperation (OR 21.9 [20.5-23.4]) and readmission (OR 18.7 [17.6-19.9]). Index pulmonary complications had the strongest association with length of stay (coefficient 9.39 [8.95-9.83]).

CONCLUSIONS

Different types of index complications are associated with different perioperative outcomes. These data can help identify patients potentially at risk for suboptimal outcomes and can inform pediatric quality improvement interventions.

TYPE OF STUDY

Cohort study.

LEVEL OF EVIDENCE

Level II.

The association between preoperative length of stay and surgical site infection after lower extremity bypass for chronic limb-threatening ischemia

OBJECTIVE

Surgical site infection (SSI) is an important complication of lower extremity bypass (LEB) and the rate of SSI after LEB varies widely in the existing literature, ranging from 4% to 31%. Prolonged length of stay (LOS) has been implicated in the occurrence of SSI across multiple surgical disciplines. The impact of preoperative LOS in patients with chronic limb-threatening ischemia (CLTI) undergoing LEB is unknown. We examined the association of preoperative LOS on SSI after LEB.

METHODS

A retrospective analysis of the Society for Vascular Surgery Vascular Quality Initiative Infrainguinal Bypass Registry identified patients undergoing elective LEB for chronic limb-threatening ischemia from 2003 to 2019. Patients undergoing LEB for acute limb ischemia, urgent/emergent procedures, aneurysm, or who had concomitant suprainguinal bypass were excluded. The primary outcome measure was postoperative SSI. Multivariable forward stepwise logistic regression was then performed including all variables with a P value of less than .10 in both matched and unmatched cohorts to evaluate for demographic and perioperative predictors of SSI. Propensity score matching was used to create matched cohorts of patients for each LOS group.

RESULTS

A total of 17,883 LEB procedures were selected for inclusion: 0 days (12,362 LEB), 1 to 2 days (1737 LEB), and 3 to 14 days (3784 LEB). Patients with the greatest preoperative LOS were more likely to have vein mapping (0 days preoperative LOS, 66.3%; 1-2 days, 65.2%; 3-14 days, 73.2%; P < .01) or computed tomography angiography/magnetic resonance angiography (0 days, 32.1%; 1-2 days, 34.4%; 3-14 days, 38.4%; P < .01). Patients with 3 or more days of preoperative LOS had longer procedure lengths (0 days, 244 minutes; 1-2 days, 243 minutes; 3-14 days, 255 minutes; P < .01) and were more likely to have completion angiogram (0 days, 27.1%; 1-2 days, 29.5%; 3-14 days, 31.6%; P = .02). Multivariable logistic regression demonstrated that preoperative LOS of 3 to 14 days was associated with increased rate of SSI (odds ratio [OR], 1.92; 95% confidence interval [CI], 1.20-3.07; P = .01). Transfusion of 3 or more units (OR, 2.87; 95% CI, 1.89-4.36; P < .01) and prolonged procedure length (>220 minutes; OR, 1.86; 95% CI, 1.26-2.73; P < .01) were also significantly associated with postoperative SSIs.

CONCLUSIONS

Many factors including preoperative comorbidities and operative complexity covary with preoperative LOS as risk factors for SSI. However, when patients are matched based on comorbidities and factors that would predict overall clinical complexity, preoperative LOS remains important in predicting SSI.

Perioperative Outcomes of Lower Extremity Revascularization for Rest Pain and Tissue Loss

BACKGROUND

Critical limb ischemia (CLI) is the clinical manifestation of severe peripheral artery disease presenting as rest pain (RP) and tissue loss (TL). Most studies compare CLI as a homogenous group with claudication with limited database studies specifically studying these differences. We hypothesize that CLI should be stratified into RP and TL because of significant differences in disease severity, comorbidities, and outcomes.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database from 2012 to 2016 was reviewed. All patients with a postoperative diagnosis of CLI undergoing femoral to popliteal bypass (FPB) with vein or graft were identified. Patients were stratified into cohorts based on International Classification of Disease (ICD)-9 or ICD-10 codes for RP or TL (gangrene or ulcer). Univariate and multivariate analyses were performed to examine 30-day mortality, morbidity, major amputation, and readmission adjusting for demographics, comorbidities, and procedural details.

RESULTS

There were 5,304 patients. Compared to RP, patients with TL were older (P < 0.0001) and more likely to be dependent (P < 0.0001). TL patients were also more likely to have diabetes (P < 0.0001), congestive heart failure (P < 0.0001), renal failure (P = 0.004), dialysis (P < 0.0001), history of wound infection (P < 0.0001), and sepsis (P < 0.0001). TL patients had higher American Society of Anesthesiologists class (P < 0.0001), were less likely to be transferred from home (P < 0.0001), and more likely to receive an FPB with vein (P = 0.03). Patients with TL had worse perioperative outcomes compared with RP in terms of pneumonia (P = 0.004), unplanned intubation (P = 0.009), cardiac arrest requiring cardiopulmonary resuscitation (P = 0.003), bleeding requiring transfusions (P < 0.0001), sepsis (P < 0.0001), septic shock (P = 0.02), and reoperation (P < 0.0001). TL was associated with significantly higher 30-day morbidity (P < 0.0001), 30-day mortality (P < 0.0001), major amputation (P = 0.0004), and readmission rates (P = 0.005). Patients with TL compared with those with RP also had longer hospital stays (P < 0.0001) and days between operation to discharge (P < 0.0001). TL was independently associated with increased 30-day morbidity (OR: 1.16 [1.00-1.35]) and major amputation (OR: 2.48 [1.29-4.76]) compared with RP.

CONCLUSIONS

Patients with RP and TL have drastic differences that impact perioperative mortality and readmissions. TL is an independent predictor of 30-day morbidity and major amputation. The stratification of CLI into RP and TL can provide insight into variations in outcomes and provide a means to quantify the risks associated with the 2 manifestations of the disease.

Sequelae of Index Complications following Inpatient Head and Neck Surgery: Characterizing Secondary Complications

Objective To characterize patterns of secondary complications after inpatient head and neck surgery. Study Design Retrospective cohort study. Setting National Surgical Quality Improvement Program (2005-2015). Subjects and Methods We identified 18,584 patients who underwent inpatient otolaryngologic surgery. Four index complications were studied: pneumonia, bleeding or transfusion event (BTE), deep/organ space surgical site infection (SSI), and myocardial infarction (MI). Each patient with an index complication was matched to a control patient based on propensity for the index event and event-free days. Rates of 30-day secondary complications and mortality were compared. Results Index pneumonia (n = 254) was associated with several complications, including reintubation (odds ratio [OR], 11.7; 95% confidence interval [CI], 5.2-26.4), sepsis (OR, 8.8; 95% CI, 4.5-17.2), and death (OR, 5.3; 95% CI, 1.9-14.9). Index MI (n = 50) was associated with increased odds of reintubation (OR, 17.2; 95% CI, 3.5-84.1), ventilatory failure (OR, 5.8; 95% CI, 1.8-19.1), and death (OR, 24.8; 95% CI, 2.9-211.4). Index deep/organ space SSI (n = 271) was associated with dehiscence (OR, 7.2; 95% CI, 3.6-14.2) and sepsis (OR, 38.3; 95% CI, 11.6-126.4). Index BTE (n = 1009) increased the odds of cardiac arrest (OR, 3.9; 95% CI, 1.8-8.5) and death (OR, 2.9; 95% CI, 1.6-5.1). Conclusions Our study is the first to quantify the effect of index complications on the risk of specific secondary complications following inpatient head and neck surgery. These associations may be used to identify patients most at risk postoperatively and target specific interventions aimed to prevent or interrupt further complications.

Postoperative complications after lower extremity arterial bypass increase the risk of new deep venous thrombosis

Background Deep venous thrombosis after any surgical operations is considered a preventable complication. Lower extremity bypass surgery is a commonly performed operation to improve blood flow to lower extremities in patients with severe peripheral arterial disease. Despite advances in endovascular surgery, lower extremity arterial bypass remains the gold standard treatment for severe, symptomatic peripheral arterial disease. The purpose of this study is to identify the clinical risk factors associated with development of deep venous thrombosis after lower extremity bypass surgery. Methods The American College of Surgeons' NSQIP database was utilized and all lower extremity bypass procedures performed in 2013 were examined. Patient and procedural characteristics were evaluated. Univariate and multivariate logistic regression analysis was used to determine independent risk factors for the development of postoperative deep venous thrombosis. Results A total of 2646 patients (65% males and 35% females) underwent lower extremity open revascularization during the year 2013. The following factors were found to be significantly associated with postoperative deep venous thrombosis: transfusion >4 units of packed red blood cells (odds ratio (OR) = 5.21, confidence interval (CI) = 1.29-22.81, p = 0.03), postoperative urinary tract infection (OR = 12.59, CI = 4.12-38.48, p < 0.01), length of hospital stay >28 days (OR = 9.30, CI = 2.79-30.92, p < 0.01), bleeding (OR = 2.93, CI = 1.27-6.73, p = 0.01), deep wound infection (OR = 3.21, CI = 1.37-7.56, p < 0.01), and unplanned reoperation (OR = 4.57, CI = 2.03-10.26, p < 0.01). Of these, multivariable analysis identified the factors independently associated with development of deep venous thrombosis after lower extremity bypass surgery to be unplanned reoperation (OR = 3.57, CI = 1.54-8.30, p < 0.01), reintubation (OR = 8.93, CI = 2.66-29.97, p < 0.01), and urinary tract infection (OR = 7.64, CI = 2.27-25.73, p < 0.01). Presence of all three factors was associated with a 54% incidence of deep venous thrombosis. Conclusions Development of deep venous thrombosis after lower extremity bypass is a serious but infrequent complication. Patients who require unplanned return to the operating room, reintubation, or develop a postoperative urinary tract are at high risk for developing postoperative deep venous thrombosis. Increased monitoring of these patients and ensuring adequate deep venous thrombosis prophylaxis for such patients is suggested.

Perioperative Infections after Open Abdominal Aortic Aneurysm Repair Lead to Increased Risk of Subsequent Complications

BACKGROUND

Patients undergoing open abdominal aortic aneurysm (AAA) repair are at risk of perioperative infections that can lead to subsequent complications. Our goal was to understand how an initial infectious complication influences the risk of subsequent complications in this cohort of patients.

METHODS

Using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database (2005-2012), we evaluated the relationship between 3 index infectious complications after open elective AAA repair (pneumonia, deep/organ surgical site infection [SSI], and urinary tract infection [UTI]) and subsequent complications. We used 5:1 propensity matching and calculated propensity score to experience to establish matching cohorts for each index complication. This score was based on preoperative variables and number of event-free days.

RESULTS

There were 3,991 patients who were identified to have undergone elective open AAA repair in the ACS-NSQIP database. Postoperative index pneumonia was associated with increased risk of unplanned intubation (28.6% vs. 3.5%; odds ratio [OR], 10.9; 95% confidence interval [CI]: 6.7-17.5; P < 0.001), prolonged ventilation (38.5% vs. 6.7%; OR, 8.7; 95% CI: 5.9-13.0; P < 0.001), sepsis (14.3% vs. 3.3%; OR, 4.8; 95% CI: 2.8-8.4; P < 0.001), acute renal failure (9.9% vs. 2.1%; OR, 5.1; 95% CI: 2.6-9.9; P < 0.001), deep vein thrombosis (DVT) (3.8% vs. 1.4%; OR, 2.7; 95% CI: 1.1-7.0; P = 0.035), and mortality (7.1% vs. 3.0%; OR, 2.5; 95% CI: 1.3-4.9; P = 0.009). Postoperative index UTI was associated with increased risk of sepsis (21.4% vs. 0%; OR, 49.2; 95% CI: 14.5-166.8; P < 0.001), pneumonia (10.7% vs. 2.9%; OR, 4.0; 95% CI: 1.8-8.6; P = 0.001), DVT (3.6% vs. 0.4%; OR, 10.0; 95% CI: 1.8-55.5; P = 0.008), and mortality (5.4% vs. 1.8%; OR, 3.0; 95% CI: 1.1-8.5; P = 0.02). Finally, postoperative index deep/organ SSI increased the risk of pneumonia (13.0% vs. 0.9%; OR, 16.7; 95% CI: 1.6-168.2; P = 0.017), prolonged ventilation (21.7% vs. 0.9%; OR, 30.8; 95% CI: 3.4-279.4; P = 0.002), and sepsis (13.0% vs. 0.9%; OR, 16.7; 95% CI: 1.6-168.2; P = 0.017).

CONCLUSIONS

A postoperative nosocomial infection after open AAA repair is significantly more likely to lead to serious subsequent complications. Prevention and early identification of infectious index complications and subsequent complications could allow for interventions that could decrease morbidity and mortality.

Use of Negative Pressure Wound Therapy for Lower Limb Bypass Incisions

Objective: The use of negative pressure wound therapy (NPWT) for post-surgical cardiothoracic, orthopedic, plastic, and obstetric and gynecologic procedures has been described. However, there are no data regarding its use for lower limb bypass incisions. We aimed to investigate the outcomes of NPWT in preventing surgical site infection (SSI) in patients with lower limb arterial bypass incisions.

Materials and Methods: We retrospectively used data of 42 patients who underwent lower limb arterial bypass with reversed great saphenous vein between March 2014 and June 2016 and compared conventional wound therapy and NPWT with regard to preventing SSI.

Results: Twenty-eight (67%) patients underwent conventional wound therapy and 14 (33%) underwent NPWT. There were no statistical differences regarding patient characteristics and mean SSI risk scores between the two patient groups (13.7% for conventional wound therapy vs. 13.4% for NPWT; P=0.831). In the conventional group, nine instances of SSI (32%) and three (11%) of these required subsequent surgical wound debridement, whereas in the NPWT group, there was no SSI incidence (P=0.019). Secondary outcomes such as the length of hospital stay, 30-day readmission rate, and need for secondary vascular procedures were not statistically different between the two groups.

Conclusion: The use of NPWT for lower limb arterial bypass incisions is superior to that of conventional wound therapy because it may prevent SSIs.