Unplanned return to operating room after lower extremity arterial bypass is an independent predictor for hospital readmission

A Systematic Review and Meta-Analysis to Assess the Impact of Pre-existing Comorbidities on the 30-Day Readmission after Lower Extremity Bypass Surgery for Peripheral Artery Occlusive Disease

BACKGROUND

Unplanned hospital readmissions after surgical operations are considered a marker for suboptimal care during index hospitalizations and are associated with poor patient outcomes and increased healthcare resource utilization. Patients undergoing lower extremity bypass (LEB) operations for severe peripheral arterial disease (PAD) have one of the highest readmission rates, among all the vascular and nonvascular surgical operations. This review is meant to evaluate the impact of pre-existing comorbidities (diabetes mellitus (DM), chronic obstructive pulmonary disease (COPD), congestive heart failure (CHF), hypertension (HTN), and coronary artery disease (CAD))-on the 30-day readmission rates among patients who underwent LEB for severe PAD.

METHODS

The review protocol was registered to the PROSPERO database (CRD42021261067). A systematic review of the English literature was performed using PubMed, Scopus, and the Cochrane Library databases from inception till April 2022. The review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines and included only studies reporting on 30-day readmission following LEB for occlusive PAD. The quality of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) approach and was reported as high, moderate, or low. The risk of bias was evaluated utilizing the Risk of Bias in Nonrandomized Studies - of Interventions (ROBINS-I) tool. A pooled odds ratio (OR) for each study was computed, and a P-value of <0.05 was designated as statistically significant. Interstudy heterogeneity was evaluated by Q-metric and quantified using Higgins I² statistics.

RESULTS

Five studies reported data on 30-day readmission after LEB for occlusive PAD. A total of 19,739 patients were included. Readmission occurred among 3,559 (18%) patients. DM and COPD were reported by all 5 selected studies, and CHF and HTN were reported by 4 studies. CAD was least reported among the selected 5 pre-existing conditions, with only 2 studies mentioning it. HTN (OR, 1.35; 95% confidence interval (CI), 1.10-1.64; P ≤ 0.001; I² = 52.20%), DM (OR, 1.52; 95% CI, 1.30-1.79; P ≤ 0.001; I² = 74.51%), and CHF (OR, 1.85; 95% CI, 1.51-2.25; P ≤ 0.001; I² = 50.48%) were all found to be associated with an increased risk of 30-day readmission, while the presence of COPD (OR, 1.16; 95% CI, 0.98-1.36; P = 0.09; I² = 61.93%) and CAD (OR, 1.30; 95% CI, 0.94-1.78; P = 0.11; I² = 51.01%) was not associated with early readmission on meta-analysis of the available studies.

CONCLUSIONS

The pre-existing comorbidities HTN, DM, and CHF increase the risk of 30-day readmission after LEB for occlusive PAD. The identification of these risk factors can help stratify the patients and further guide in understanding the variety of factors that contribute in hospital readmissions.

Machine learning in prediction of individual patient readmissions for elective carotid endarterectomy, aortofemoral bypass/aortic aneurysm repair, and femoral-distal arterial bypass

Objective:

Early hospital readmissions have been rising and are increasingly used for public reporting and pay-for-performance. The readmission problem is fundamentally different in surgical patients compared with medical patients. There is an opportunity to intervene preoperatively to decrease the risk of readmission postoperatively.

Methods:

A predictive model of 90-day hospital readmission for patients undergoing elective carotid endarterectomy, aortofemoral bypass/aortic aneurysm repair, and femoral-distal arterial bypass was developed using data from the Healthcare Cost and Utilization Project State Inpatient Database for Florida State. The model training followed a nested resampling method with subsampling to increase execution speed and reduce overfitting. The following predictors were used: age, gender, race, median household income, primary expected payer, patient location, admission type, Elixhauser–van Walraven Comorbidity Index, Charlson comorbidity score, main surgical procedure, length of stay, disposition of the patient at discharge, period of the year, hospital volume, and surgeon volume.

Results:

Our sample comprised data on 246,405 patients, of whom 30.3% were readmitted within 90 days. Readmitted patients were more likely to be admitted via emergency (47.2% vs 30%), included a higher percentage with a Charlson score greater than 3 (35.8% vs 18.7%), had a higher mean van Walraven score (8.32 vs 5.34), and had a higher mean length of hospital stay (6.59 vs 3.51). Endarterectomy was the most common procedure, accounting for 19.9% of all procedures. When predicting 90-day readmission, Shrinkage Discriminant Analysis was the best performing model (area under the curve = 0.68). Important variables for the best predictive model included length of stay in the hospital, comorbidity scores, endarterectomy procedure, and elective admission type. The survival analysis for the time to readmission after the surgical procedures demonstrated that the hazard ratios were higher for subjects who presented Charlson comorbidity score above three (2.29 (2.26, 2.33)), patients transferred to a short-term hospital (2.4 (2.23, 2.59)), home healthcare (1.64 (1.61, 1.68)), other type of facility (2.59 (2.54, 2.63)) or discharged against medical advice (2.06 (1.88, 2.26)), and those with greater length of stay (1.89 (1.86, 1.91)).

Conclusion:

The model stratifies readmission risk on the basis of vascular procedure type, which suggests that attempts to decrease vascular readmission should focus on emergency procedures. Given the current focus on readmissions and increasing pressure to prevent unplanned readmissions, this score stratifies patients by readmission risk, providing an additional resource to identify and prevent unnecessary readmissions.

A systematic review and meta-analysis of risk factors for and incidence of 30-day readmission after revascularization for peripheral artery disease

OBJECTIVE

Readmission to the hospital after revascularization for peripheral artery disease (PAD) is frequently reported. No consensus exists as to the exact frequency and risk factors for readmission. This review aimed to determine the incidence of and risk factors for 30-day readmission after revascularization for PAD.

METHODS

PubMed/Medline (Ovid), Scopus, Web of Science, the Cochrane Library, and CINAHL were searched systematically from inception until May 20, 2018. Studies were eligible for inclusion if they included patients with diagnosed PAD undergoing revascularization and reported the readmission rate and a statistical evaluation of the association of at least one risk factor with readmission. Studies were excluded if data for other procedures could not be distinguished from revascularization. Two authors undertook study selection independently with the final inclusion decision resolved through consensus. The PRISMA and Meta-analyses of Observational Studies in Epidemiology guidelines were followed regarding data extraction and quality assessment, which was performed by two authors independently. Data were pooled using a random effects model.

RESULTS

The primary outcome was readmission within 30 days of revascularization. Fourteen publications reporting the outcomes of 526,008 patients were included. Reported readmission rates ranged from 10.9% to 30.0% with a mean of 16.4% (95% confidence interval [CI], 15.1%-17.9%). Meta-analyses suggested the following risk factors had a significant association with readmission: female sex (odds ratio [OR], 1.13; 95% CI, 1.05-1.21), black race (OR, 1.36; 95% CI, 1.28-1.46), dependent functional status (OR, 1.72; 95% CI, 1.43-2.06), critical limb ischemia (OR, 2.12; 95% CI, 1.72-2.62), emergency admission (OR, 1.75; 95% CI, 1.43-2.15), hypertension (OR, 1.39; 95% CI, 1.26-1.54), heart failure (OR, 1.82; 95% CI, 1.50-2.20), chronic pulmonary disease (OR, 1.19; 95% CI, 1.08-1.32), diabetes (OR, 1.47; 95% CI, 1.32-1.63), chronic kidney disease (OR, 1.93; 95% CI, 1.62-2.31), dialysis dependence (OR, 2.08; 95% CI, 1.75-2.48), smoking (OR, 0.83; 95% CI, 0.78-0.89), postoperative bleeding (OR, 1.70; 95% CI, 1.23-2.35), and postoperative sepsis (OR, 4.13; 95% CI, 2.02-8.47).

CONCLUSIONS

Approximately one in six patients undergoing revascularization for PAD are readmitted within 30 days of their procedure. This review identified multiple risk factors predisposing to readmission, which could potentially serve as a way to target interventions to reduce readmissions.

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.

Factors Associated with Increased Risk of Unplanned Hospital Readmission after Endovascular Aortoiliac Interventions

Objectives   Readmissions to hospital after surgical procedures are considered as reflective of poor quality of healthcare provided during the index hospitalization and are associated with increased costs of healthcare. Aortoiliac occlusive disease represents an aggressive form of atherosclerotic disease and has been traditionally treated with open surgical bypasses. Endovascular interventions for aortoiliac occlusive disease are associated with comparable outcomes to open surgical procedures. The purpose of this study is to review the factors associated with hospital readmission after aortoiliac endovascular interventions. Methods The 2015 procedure targeted American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database and general and vascular surgery NSQIP participant user file (PUF) were used for this analysis. Patient, diagnosis and procedure characteristics of patients undergoing aortoiliac endovascular interventions were reviewed. Bivariate analysis was used to identify the relationship between the independent variables and 30-day readmission. The significant variables from the bivariate analysis were used to generate a multivariable logistic regression model. The predicted probability of readmission was calculated. Results Out of 823 patients, 86 were readmitted. Readmission was related to the principal procedure in 48 (73.9%) patients. A total of 61 (7%) patients underwent an unplanned operation within 30 days after the index procedure. A multivariable logistic regression model identified the following variables to be significantly associated with 30-day risk of readmission: the use of pre-procedural beta blocker (OR = 2.06, 95% CI = 1.23 - 3.45, P < 0.01), external/internal iliac intervention (OR = 1.95, 95% CI = 1.18 - 3.20, P <0.01), critical limb ischemia (OR = 1.80, 95% CI = 1.10 - 2.94, P <0.05), and unplanned return to the operating room (OR = 11.65, 95% CI = 6.35 - 21.35, P <0.01). The predicted probability of readmission was as follows: 5.5% for critical limb ischemia, 5.9% for external iliac artery angioplasty/stenting, 6.2% for preoperative beta blockers, 17.7% for patients with cardiac arrest, 27% for unplanned return to the operating room, and 94.7% for patients with all of these risk factors. Conclusion Readmissions after endovascular interventions for severe atherosclerotic disease can be used as a quality metric. Several factors place a patient at a high risk for readmission. Unplanned return to the operating room, cardiac arrest, preoperative beta blockers, location of disease, and preoperative symptoms are independent risk factors for hospital readmission. Unplanned return to the operating room is associated with 11.65-fold increase in the risk of hospital readmission.

A risk score model of 30-day readmission in ulcerative colitis after colectomy or proctectomy

INTRODUCTION

The Center for Medicare and Medicaid Services established 30-day readmission rate as a key metric in measuring high-value, cost-conscious care; therefore, our aim is to develop a risk score for 30-day readmission in ulcerative colitis (UC) patients undergoing colectomy or proctectomy.

METHODS

This study used data from the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) participant user file (2011-2015). Patients with UC undergoing colectomy or proctectomy were identified using ICD-9, 10, and CPT codes. Stepwise multivariate analyses were used to determine risk factors associated with readmission including pre-operative conditions, laboratory results, operative variables, and post-operative complications. For readmission risk score assessment, a weighted logistic regression model was built and validated using ACS NSQIP 2011-2014 and 2015 data, respectively.

RESULTS

A total of 4797 patients were included with 963 (20%) patients readmitted within 30 days. Potentially modifiable risk factors included deep vein thrombosis, pulmonary embolism, renal insufficiency, wound infection, urinary tract infection, sepsis/septic shock, and pre-existing congestive heart failure. Ten percent of patients with a risk score between 0 and 9 were readmitted, 18.5% with a score between 10 and 19, 52.2% with a score between 20 and 29, and 59.6% in patients with a risk score >29.

CONCLUSIONS

Multiple potentially preventable risk factors are associated with 30-day readmission following colectomy or proctectomy in UC patients. Higher risk scores are associated with increased risk of unplanned readmission.

Preexisting Conditions Determine the Occurrence of Unplanned Readmissions after Procedures for Treatment of Peripheral Arterial Disease

BACKGROUND

Readmissions after surgical procedures are increasingly considered a metric to indicate the quality of care received during the index hospitalization. Patients with peripheral arterial disease (PAD) requiring peripheral vascular interventions (PVIs) or lower extremity bypasses (LEBs) often have several serious medical comorbidities. Risk factors associated with readmission after PVI and LEB have previously been identified. The purpose of this study is to compare the readmissions among patients receiving PVI and LEB procedures to identify risk factors associated with high risk of readmission.

METHODS

The 2013 Procedure-targeted American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database and generalized 2013 general and vascular surgery ACS-NSQIP Program User Files were used for this study. Patient, diagnosis, and procedure characteristics of patients undergoing PVI and LEB were assessed. Odds ratios (ORs) with confidence intervals (CIs) for PVI versus LEB groups within the subgroups of these characteristics were then obtained where significant associations existed between the study groups.

RESULTS

A total of 3,742 patients (males: 2,384 [63.7%] and females: 1,358 [36.3%]) underwent surgical procedures for lower extremity PAD during the year 2013. Among these patients, 1,096 (29.3%) were treated with endovascular interventions and 2,646 (70.7%) were treated with surgical bypasses. Patients were divided into 2 groups: PVI (n = 1,096) and LEB (n = 2,646) groups. Each group was further subdivided into 2 groups: readmission and no readmission. The incidence of readmission was as follows: PVI group (n = 147, 13.4%) and LEB (n = 425, 16.1%). The PVI and LEB groups showed a significant association with readmission within the following factors: dialysis dependency (PVI 32.6% vs. LEB 19.1%, OR: 2.06, CI: 1.13-3.75, P < 0.001), emergency operation (PVI 40.4% vs. LEB 18.7%, OR: 2.96, CI: 1.45-6.03, P < 0.001), chronic obstructive pulmonary disease (COPD; PVI 23.7% vs. LEB 14.6%, OR: 1.82, CI: 1.08-3.07, P = 0.001), cardiac arrest (PVI 45.5% vs. LEB 9.5%, OR: 7.92, CI: 1.21-51.9, P = 0.017), and body mass index > 30 (PVI 9.9% vs. LEB 18.4%, OR: 0.49, CI: 0.33-0.73, P = 0.009).

CONCLUSIONS

Readmissions after lower extremity endovascular or surgical interventions can be used as a quality metric. Patients with dialysis dependency, COPD, in need of emergent operation, or having cardiac arrest are highly likely to be readmitted if treated with endovascular interventions. Similarly, patients with high body mass index are highly likely to be readmitted if treated with open surgical bypasses.

Fewer Complications in the Obese Following Lower Extremity Endovascular Interventions

BACKGROUND

The prevalence of obesity is increasing in the United States; however, its impact on adverse outcomes in patients with peripheral vascular disease is not well studied. Obesity is associated with higher rates of complications following open bypass surgery, but limited data are available on its effect on endovascular intervention. This study aimed to identify whether obese patients suffer the same complications when undergoing lower extremity endovascular interventions.

METHODS

All patients who underwent femoropopliteal or tibial endovascular interventions between 2011 and 2013 were identified in the Targeted Vascular Module of the National Surgical Quality Improvement Program. Patients were stratified into 5 groups based on their body mass index (BMI): underweight (<18.6), normal weight (18.6-24.9), overweight (25-29.9), obese (30-34.9), and morbidly obese (≥35). Those patients without a documented BMI or a defined target lesion were excluded. Baseline demographics, patient characteristics, operative details, and outcomes were compared using univariate analysis between the BMI groups. Multivariable logistic regression was used to account for patient demographics and operative details.

RESULTS

3,246 patients underwent endovascular interventions (78% femoropopliteal and 22% tibial). Of these, 137 (4%) were underweight, 881 (27%) were normal weight, 1,193 (37%) were overweight, 647 (20%) were obese, and 388 (12%) were morbidly obese. There were no differences in 30-day mortality; however, surgical site infection (SSI) was higher in the morbidly obese (5% vs. normal weight: 2%, P = 0.02), whereas untreated patency loss was lower (morbidly obese: 0.5%, obese: 1%, normal weight: 2%, P = 0.02). Other important 30-day outcomes, including bleeding and amputation, were similar across the BMI groups. Following multivariate analysis, SSI remained more common in the morbidly obese (odds ratio [OR]: 2.6, 95% confidence interval [CI]: 1.4-5.0), whereas untreated patency loss remained lower in both overweight and morbidly obese patients (overweight: OR 0.5, 95% CI: 0.2-0.9 and morbidly obese: OR: 0.2, 95% CI: 0.05-0.85). Length of stay >1 day was significantly lower in the overweight, obese, and morbidly obese (OR 0.7, 95% CI: 0.6-0.8; OR 0.6, 95% CI: 0.5-0.7; and OR 0.7, 95% CI: 0.5-0.9, respectively).

CONCLUSIONS

Few major complications occur in the obese in the first 30 days following endovascular interventions, and obesity is not an independent predictor of 30-day mortality. Rates of postoperative SSIs are low overall, although they are highest in morbidly obese patients (5%, compared to 2% in normal weight patients). Given this knowledge, endovascular interventions are a prudent treatment option for this patient population.

Unplanned return to operating room after endovascular repair of abdominal aortic aneurysm (EVAR) is associated with increased risk of hospital readmission

Objectives Hospital readmissions after surgical operations are considered serious events. Centers for Medicare and Medicaid (CMS) consider surgical readmissions as preventable and hold hospitals responsible for them. Endovascular abdominal aortic aneurysm (EVAR) has become the first line modality of treatment for suitable patients with abdominal aortic aneurysm (AAA). The purpose of this study is to retrospectively review the factors associated with hospital readmission after EVAR. Methods The 2013 EVAR targeted American College of Surgeons (ACS-NSQIP) database and generalized 2013 general and vascular surgery ACS-NSQIP participant use files were used for this study. Patient, diagnosis, and procedure characteristics of patients undergoing EVAR surgery were assessed. Multivariate logistic regression analysis was used to determine independent risk factors for hospital readmission within 30 days after surgery. Results A total of 2277 patients (81% males, 19% females) underwent EVAR operations in the year 2013. Indications for operations included: asymptomatic large diameter (79%), symptomatic (5.7%), rupture without hypotension (4.3%), and rupture with hypotension (2.8%). Among these patients, 178 (7.8%) were readmitted to the hospital within 30 days after surgery. About 53% of all readmissions were within two weeks after the discharge. Risk factors, associated with readmission included: body mass index (per 5-units, OR 1.23, CI 1.06-1.42, p < 0.05), days from admission to operation (per 1 day, OR 1.26, CI 1.12-1.41, p < 0.05), prior abdominal aortic surgery (OR 1.60, CI 1.10-2.31, p < 0.05), urinary tract infection (OR 5.93, CI 2.09-16.88, p < 0.05), superficial surgical site infection (OR 6.57, CI 2.53-17.09, p < 0.05), unplanned return to the operating room (OR 11.29, CI 6.29-20.28, p < 0.05), myocardial infarction (OR 11.30, CI 4.42-28.89, p < 0.05), deep venous thrombosis (OR 11.52, CI 2.89-45.86, p < 0.05 and deep incisional surgical site infection (OR 38.0, CI 2.87-373.56, p < 0.05). Risk of readmission for patients with presence of all these seven factors was 99.9%. Conclusions Readmission after EVAR is a serious occurrence. Various factors predispose a patient at a high risk for readmission. Unplanned return to operating room after EVAR is associated with a 11-fold increase in hospital readmission.

Risk factors for 30-day unplanned readmission following infrainguinal endovascular interventions

OBJECTIVE

Unplanned hospital readmissions following surgical interventions are associated with adverse events and contribute to increasing health care costs. Despite numerous studies defining risk factors following lower extremity bypass surgery, evidence regarding readmission after endovascular interventions is limited. This study aimed to identify predictors of 30-day unplanned readmission following infrainguinal endovascular interventions.

METHODS

We identified all patients undergoing an infrainguinal endovascular intervention in the targeted vascular module of the American College of Surgeons National Surgical Quality Improvement Program between 2012 and 2014. Perioperative outcomes were stratified by symptom status (chronic limb-threatening ischemia [CLI] vs claudication). Patients who died during index admission and those who remained in the hospital after 30 days were excluded. Indications for unplanned readmission related to the index procedure were evaluated. Multivariable logistic regression was used to identify preoperative and in-hospital (during index admission) risk factors of 30-day unplanned readmission.

RESULTS

There were 4449 patients who underwent infrainguinal endovascular intervention, of whom 2802 (63%) had CLI (66% tissue loss) and 1647 (37%) had claudication. The unplanned readmission rates for CLI and claudication patients were 16% (n = 447) and 6.5% (n = 107), respectively. Mortality after index admission was higher for readmitted patients compared with those not readmitted (CLI, 3.4% vs 0.7% [P < .001]; claudication, 2.8% vs 0.1% [P < .01]). Approximately 50% of all unplanned readmissions were related to the index procedure. Among CLI patients, the most common indication for readmission related to the index procedure was wound or infection related (42%), whereas patients with claudication were mainly readmitted for recurrent symptoms of peripheral vascular disease (28%). In patients with CLI, predictors of unplanned readmission included diabetes (odds ratio, 1.3; 95% confidence interval, 1.01-1.6), congestive heart failure (1.6; 1.1-2.5), renal insufficiency (1.7; 1.3-2.2), preoperative dialysis (1.4; 1.02-1.9), tibial angioplasty/stenting (1.3; 1.04-1.6), in-hospital bleeding (1.9; 1.04-3.5), in-hospital unplanned return to the operating room (1.9; 1.1-3.5), and discharge other than to home (1.5; 1.1-2.0). Risk factors for those with claudication were dependent functional status (3.5; 1.4-8.7), smoking (1.6; 1.02-2.5), diabetes (1.5; 1.01-2.3), preoperative dialysis (3.6; 1.6-8.3), procedure time exceeding 120 minutes (1.8; 1.1-2.7), in-hospital bleeding (2.9; 1.2-7.4), and in-hospital unplanned return to the operating room (3.4; 1.2-9.4).

CONCLUSIONS

Unplanned readmission after endovascular treatment is relatively common, especially in patients with CLI, and is associated with substantially increased mortality. Awareness of these risk factors will help providers identify patients at high risk who may benefit from early surveillance, and prophylactic measures focused on decreasing postoperative complications may reduce the rate of readmission.

Pre-operative predictors of poor outcomes in patients undergoing surgical lower extremity revascularisation - Retrospective cohort study

BACKGROUND

Surgical lower extremity revascularisation (LER) can lead to poor outcomes that include delayed hospital discharge, in-hospital mortality, major amputations and readmissions. The aim of this study was to identify pre-operative predictors associated with these poor clinical outcomes.

MATERIALS AND METHODS

All patients (n = 635; mean age 69; male 67.4%) who underwent surgical LER over a 5 year period in a single tertiary vascular institution were identified. Patients considered to have suffered a poor outcome (Group A) included all in-hospital mortality and major amputations, delayed discharges with a length of stay (LOS) over one standard deviation above the mean or any readmission under any specialty within 12 months. Group A included 247 patients (38.9%) and the good outcome group included the remaining 388 patients (61.1%) from which a sample of 99 patients were selected as controls (Group B).

RESULTS

Mean LOS for the entire study group was 14.4 ± 17.5 days, 12 month readmission rate was 29.1% and in-hospital mortality and major amputation rate was 2.7% and 1.4%, respectively. Pre-admission residence other than own home (OR 9.0; 95% CI 1.2-70.1; P = 0.036), atherosclerotic disease burden (OR 2.2; 95% CI 1.3-3.8; P = 0.003) and tissue loss (OR 3.0; 95% CI 1.6-5.3; P < 0.001) were identified as independent, statistically significant pre-operative predictors of poor outcome. Following discharge, group B patients had a significantly higher rate of amputation free survival and graft infection free survival (P < 0.001) compared to group A.

CONCLUSION

Recognition of pre-operative predictors of poor outcome should inform case selection and identify high risk patients requiring intensive perioperative optimisation and post discharge follow up.

Relationship Between the Middle Genicular Artery and the Posterior Structures of the Knee: A Cadaveric Study

Background:

The middle genicular artery (MGA) is responsible for the blood supply to the cruciate ligaments and synovial tissue. Traumatic sports injuries and surgical procedures (open and arthroscopic) can cause vascular damage. Little attention has been devoted to establish safe parameters for the MGA.

Purpose:

To investigate the anatomy of the MGA and its relation to the posterior structures of the knees, mainly the posterior capsule and femoral condyles, and to establish safe parameters to avoid harming the MGA.

Study Design:

Descriptive laboratory study.

Methods:

Dissection of the MGA was performed in 16 fresh, unpaired adult human cadaveric knees with no macroscopic degenerative or traumatic changes and no previous surgeries. The specimens were meticulously evaluated with emphasis on preservation of the MGA. The distances from the MGA to the medial and lateral femoral condyles were measured. The Mann-Whitney test was used for statistical analysis.

Results:

In all specimens, the MGA emerged from the anterior aspect of the popliteal artery, distal to the superior genicular arteries, and had a short distal trajectory toward the posterior capsule where it entered proximal to the oblique popliteal ligament. The artery lay in the midportion between the condyles. The distance between the posterior aspect of the tibia and the point of entry of the MGA into the posterior joint capsule was 23.8 ± 7.3 mm (range, 14.72-35.68 mm). There was no correlation between an individual’s height and the distance of the entrance point of the MGA into the posterior joint capsule to the posterior superior corner of the tibia.

Conclusion:

The middle genicular artery lies in the midportion between the medial and lateral femoral condyles.

Clinical Relevance:

This knowledge is important for the preservation of the blood supply during posterior knee surgical procedures and to settle a secure distance between the posterior aspect of the tibia and the MGA input. This could decrease and prevent iatrogenic vascular injury risk to the MGA.