Predicting outcomes following lower extremity open revascularization using machine learning.

Lower extremity open revascularization is a treatment option for peripheral artery disease that carries significant peri-operative risks; however, outcome prediction tools remain limited. Using machine learning (ML), we developed automated algorithms that predict 30-day outcomes following lower extremity open revascularization. The National Surgical Quality Improvement Program targeted vascular database was used to identify patients who underwent lower extremity open revascularization for chronic atherosclerotic disease between 2011 and 2021. Input features included 37 pre-operative demographic/clinical variables. The primary outcome was 30-day major adverse limb event (MALE; composite of untreated loss of patency, major reintervention, or major amputation) or death. Our data were split into training (70%) and test (30%) sets. Using tenfold cross-validation, we trained 6 ML models. Overall, 24,309 patients were included. The primary outcome of 30-day MALE or death occurred in 2349 (9.3%) patients. Our best performing prediction model was XGBoost, achieving an area under the receiver operating characteristic curve (95% CI) of 0.93 (0.92-0.94). The calibration plot showed good agreement between predicted and observed event probabilities with a Brier score of 0.08. Our ML algorithm has potential for important utility in guiding risk mitigation strategies for patients being considered for lower extremity open revascularization to improve outcomes.

Predicting Outcomes Following Endovascular Abdominal Aortic Aneurysm Repair Using Machine Learning.

OBJECTIVE: To develop machine learning (ML) models that predict outcomes following endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA). BACKGROUND: EVAR carries non-negligible perioperative risks; however, there are no widely used outcome prediction tools. METHODS: The National Surgical Quality Improvement Program targeted database was used to identify patients who underwent EVAR for infrarenal AAA between 2011 and 2021. Input features included 36 preoperative variables. The primary outcome was 30-day major adverse cardiovascular event (composite of myocardial infarction, stroke, or death). Data were split into training (70%) and test (30%) sets. Using 10-fold cross-validation, 6 ML models were trained using preoperative features. The primary model evaluation metric was area under the receiver operating characteristic curve. Model robustness was evaluated with calibration plot and Brier score. Subgroup analysis was performed to assess model performance based on age, sex, race, ethnicity, and prior AAA repair. RESULTS: Overall, 16,282 patients were included. The primary outcome of 30-day major adverse cardiovascular event occurred in 390 (2.4%) patients. Our best-performing prediction model was XGBoost, achieving an area under the receiver operating characteristic curve (95% CI) of 0.95 (0.94-0.96) compared with logistic regression [0.72 [0.70-0.74)]. The calibration plot showed good agreement between predicted and observed event probabilities with a Brier score of 0.06. Model performance remained robust on all subgroup analyses. CONCLUSIONS: Our newer ML models accurately predict 30-day outcomes following EVAR using preoperative data and perform better than logistic regression. Our automated algorithms can guide risk mitigation strategies for patients being considered for EVAR.

Predicting Major Adverse Cardiovascular Events Following Carotid Endarterectomy Using Machine Learning.

Background Carotid endarterectomy (CEA) is a major vascular operation for stroke prevention that carries significant perioperative risks; however, outcome prediction tools remain limited. The authors developed machine learning algorithms to predict outcomes following CEA. Methods and Results The National Surgical Quality Improvement Program targeted vascular database was used to identify patients who underwent CEA between 2011 and 2021. Input features included 36 preoperative demographic/clinical variables. The primary outcome was 30-day major adverse cardiovascular events (composite of stroke, myocardial infarction, or death). The data were split into training (70%) and test (30%) sets. Using 10-fold cross-validation, 6 machine learning models were trained using preoperative features. The primary metric for evaluating model performance was area under the receiver operating characteristic curve. Model robustness was evaluated with calibration plot and Brier score. Overall, 38 853 patients underwent CEA during the study period. Thirty-day major adverse cardiovascular events occurred in 1683 (4.3%) patients. The best performing prediction model was XGBoost, achieving an area under the receiver operating characteristic curve of 0.91 (95% CI, 0.90-0.92). In comparison, logistic regression had an area under the receiver operating characteristic curve of 0.62 (95% CI, 0.60-0.64), and existing tools in the literature demonstrate area under the receiver operating characteristic curve values ranging from 0.58 to 0.74. The calibration plot showed good agreement between predicted and observed event probabilities with a Brier score of 0.02. The strongest predictive feature in our algorithm was carotid symptom status. Conclusions The machine learning models accurately predicted 30-day outcomes following CEA using preoperative data and performed better than existing tools. They have potential for important utility in guiding risk-mitigation strategies to improve outcomes for patients being considered for CEA.

Predicting outcomes following open revascularization for aortoiliac occlusive disease using machine learning.

OBJECTIVE: Open surgical treatment options for aortoiliac occlusive disease carry significant perioperative risks; however, outcome prediction tools remain limited. Using machine learning (ML), we developed automated algorithms that predict 30-day outcomes following open aortoiliac revascularization. METHODS: The National Surgical Quality Improvement Program (NSQIP) targeted vascular database was used to identify patients who underwent open aortoiliac revascularization for atherosclerotic disease between 2011 and 2021. Input features included 38 preoperative demographic/clinical variables. The primary outcome was 30-day major adverse limb event (MALE; composite of untreated loss of patency, major reintervention, or major amputation) or death. The 30-day secondary outcomes were individual components of the primary outcome, major adverse cardiovascular event (MACE; composite of myocardial infarction, stroke, or death), individual components of MACE, wound complication, bleeding, other morbidity, non-home discharge, and unplanned readmission. Our data were split into training (70%) and test (30%) sets. Using 10-fold cross-validation, we trained six ML models using preoperative features. The primary model evaluation metric was area under the receiver operating characteristic curve (AUROC). Model robustness was evaluated with calibration plot and Brier score. Variable importance scores were calculated to determine the top 10 predictive features. Performance was assessed on subgroups based on age, sex, race, ethnicity, symptom status, procedure type, and urgency. RESULTS: Overall, 9649 patients were included. The primary outcome of 30-day MALE or death occurred in 1021 patients (10.6%). Our best performing prediction model for 30-day MALE or death was XGBoost, achieving an AUROC of 0.95 (95% confidence interval [CI], 0.94-0.96). In comparison, logistic regression had an AUROC of 0.79 (95% CI, 0.77-0.81). For 30-day secondary outcomes, XGBoost achieved AUROCs between 0.87 and 0.97 (untreated loss of patency [0.95], major reintervention [0.88], major amputation [0.96], death [0.97], MACE [0.95], myocardial infarction [0.88], stroke [0.93], wound complication [0.94], bleeding [0.87], other morbidity [0.96], non-home discharge [0.90], and unplanned readmission [0.91]). The calibration plot showed good agreement between predicted and observed event probabilities with a Brier score of 0.05. The strongest predictive feature in our algorithm was chronic limb-threatening ischemia. Model performance remained robust on all subgroup analyses of specific demographic/clinical populations. CONCLUSIONS: Our ML models accurately predict 30-day outcomes following open aortoiliac revascularization using preoperative data, performing better than logistic regression. They have potential for important utility in guiding risk-mitigation strategies for patients being considered for open aortoiliac revascularization to improve outcomes.

General Versus Locoregional Anesthesia in TEVAR: An NSQIP Analysis.

BACKGROUND: Thoracic Endovascular Aortic Repair (TEVAR) is a minimally invasive surgery for repairing thoracic aneurysms and dissections. This study aims to compare postoperative outcomes of TEVAR performed under general versus locoregional anesthesia. METHODS: Utilizing the 2008-2019 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database, patients older than the age of 18 years who received TEVAR, were identified using the following current procedural terminology codes: 33,880, 33,881, 33,883, 33,884, or 33,886. Patients who underwent concomitant procedures, those with both thoracoabdominal and abdominal aortic pathologies, and trauma cases were excluded. Standard descriptive statistics, in addition to χ2, Fisher's exact test, and Mann-Whitney U-tests were used to compare patient baseline characteristics and postoperative outcomes between general and locoregional anesthesia groups as appropriate. Univariable and multivariable logistic regression analyses were performed to assess independent predictors of hospital length of stay (LOS) greater than 7 days. RESULTS: Of the 1,028 patients included in the study, 86.5% received general anesthesia, and 13.5% received locoregional anesthesia, such as local anesthesia with monitored anesthesia care or regional anesthesia. No significant differences were found between patients receiving locoregional versus general anesthesia in mortality (3.6% vs. 7.9%, respectively, P = 0.071) and morbidity (18.7% and 24.8%, respectively, P = 0.121) within 30 days post-TEVAR, including any wound, pulmonary, thromboembolic, renal, septic, and cardiac arrest complications. Patients who received general anesthesia had significantly higher median LOS compared to those who received locoregional anesthesia [5 days (interquartile range (IQR): 3-10) versus 4 days (IQR: 2-7), P = 0.002], with 34.3% of the general anesthesia group having an LOS greater than 7 days compared to 21.6% of locoregional anesthesia group, P = 0.003. On multivariable logistic regression analysis, general anesthesia was found to be an independent predictor of prolonged LOS greater than 7 days (odds ratio (OR): 1.72, 95% confidence interval (CI): 1.05-2.81, P = 0.031). CONCLUSIONS: Locoregional anesthesia results in significantly lower postoperative hospital LOS with similar postoperative mortality and morbidity compared to general anesthesia in patients undergoing TEVAR.

Outcomes and Cost-Analysis of Open Versus Endovascular Abdominal Aortic Aneurysm Repair in a Developing Country: A 15-year Experience at a Tertiary Medical Center.

BACKGROUND: Endovascular aortic aneurysm repair (EVAR) has become the most common procedure for treating abdominal aortic aneurysms based on multiple studies conducted in the western world. The implication of such findings in developing countries is not well demonstrated. The objective of this study was to compare medical outcomes and costs of EVAR and open surgical repair (OSR) in a developing country. METHODS: This is a retrospective study of all patients undergoing elective abdominal aortic aneurysm repair between 2005 and 2020 at a tertiary medical center in a developing country. Medical records were used to retrieve demographics, comorbidities, and perioperative complications. Medical records were also used to provide data on the need of reintervention, date of last follow-up, and mortality. RESULTS: The study included a total of 164 patients. Median follow-up time was 41 months. The mean age was 69.9 +/- 7.84 years and 90.24% (n = 148) of patients were males. Regarding long-term mortality outcomes, no significant difference was detected between both groups; OSR patients had a survival rate of 91.38% and 74.86% at 5 and 10 years, compared to 77.29% and 56.52% in the EVAR group (P value = 0.10). Both groups had comparable long-term reintervention rates (P value = 0.334). The OSR group was charged significantly less than the EVAR group ($27,666.35 vs. $44,528.04, P value = 0.008). CONCLUSIONS: OSR and EVAR have comparable survival and reintervention outcomes. Unlike what was reported in developed countries, patients undergoing OSR in countries with low hospital stay costs incur lower treatment costs.

Lower limb amputation following venous cannulation for VA-ECMO: a case report.

Lower limb amputation following arterial cannulation for VA-ECMO has been described in the literature. Limb ischemia however following venous cannulation is very rare and not quite understood. We present a case of limb ischemia following venous cannulation. A combination of venous congestion, compartment syndrome and subsequent arterial insufficiency is the proposed pathophysiology. Shock and use of vasopressors are compounding factors. Limb ischemia can be transient and reversible if diagnosed immediately and treated by early removal of the cannula. Our patient was unstable and ECMO dependent, and removal of the cannula was not an option. This resulted in limb loss and eventual above knee amputation. Use of the smallest appropriate venous cannula and early fasciotomy, in addition to hemodynamic optimization are measures that could help in preventing major amputation.

Thromboembolectomy for acute lower limb ischemia: Contemporary outcomes of two surgical methods from a single tertiary center.

OBJECTIVES: The current treatment of acute lower limb ischemia (ALLI) includes open surgical and percutaneous pharmaco-mechanical thromboembolectomy (TE). We hereby report our results with open surgical TE over a 10-year period and compare our outcomes using routine fluoroscopic assisted TE (FATE) with blind and selective on demand fluoroscopic-assisted TE (BSTE). METHODS: This is a retrospective analysis of all patients who underwent open surgical TE for acute lower limb ischemia at a single tertiary center between 2008 and 2018. Patients were divided into a group who underwent BSTE and another who underwent routine FATE. Data on presentation, medical history, surgery performed, and short-term outcomes were retrieved from medical record. Comparison between baseline characteristics and outcomes of both groups were made using t-test and chi-square analysis. RESULTS: Over 10 years, 108 patients underwent surgical TE. Thirty-day mortality rate and 30-day major lower extremity amputation rate in the cohort were 12.0% and 6.5%, respectively. On subgroup analysis, 53 patients were treated by BSTE and 55 patients by FATE. There was no significant difference in 30-day mortality rate (11.3% vs 12.7%, p-value = .82) and 30-day major amputation rate (9.4% vs 3.6%, p-value = .454) between the two groups. Local anesthesia was more frequently performed in patients undergoing FATE (58.2% vs 24.5%, p-value < .001). More than one arteriotomy was more frequently required in patients undergoing BSTE (2.6% vs 45.5%, p-value < .001). Patients with infrapopliteal involvement undergoing FATE required less further interventions such as patch angioplasty (2.6% vs 36.4%, p-value < .001) and bypass (2.6% vs 22.7%, p-value = .01). CONCLUSION: ALLI remains a disease of high morbidity and mortality. Open surgical TE offers an effective approach to treat ALLI. The addition of fluoroscopy to the conduction of TE could be associated with valuable benefits, especially in patients with infra-popliteal involvement. Randomized controlled trials are needed to objectively assess the therapeutic potential of FATE.

Face-to-face versus distance learning of basic suturing skills in novice learners: a quantitative prospective randomized trial.

BACKGROUND AND AIM: Traditionally, practical skills are taught on face-to-face (F-F) basis. COVID-19 pandemic brought distance learning (DL) to the spotlight because of the social distancing mandates. We sought to determine the acceptability and effectiveness of DL of basic suturing in novice learners. METHODS: A prospective randomized controlled trial involving 118 students was conducted. Participants were randomized into two groups for learning simple interrupted suturing: F-F and DL-groups. Evaluation was conducted by two assessors using a performance checklist and a global rating tool. Agreement between the assessors was calculated, and performance scores of the participants were compared. Participants' satisfaction was assessed via a questionnaire. RESULTS: Fifty-nine students were randomized to the F-F group and 59 to the DL-group. Satisfactory agreement between the assessors was demonstrated. All participants were successful in placing three interrupted sutures, with no significant difference in the performance between the groups. 25(44.6%) of the respondents in the DL-group provided negative comments related to the difficulties of remotely learning visuospatial concepts, 16(28.5%) preferred the F-F approach. CONCLUSION: DL of basic suturing is as effective as the F-F approach in novice learners. It is acceptable by the students despite the challenges related to the remote learning of practical skills.

Incidence and Predictors of Surgical Site Infection Complications in Diabetic Patients Undergoing Lower Limb Amputation.

BACKGROUND: Surgical site infections (SSIs) following lower extremity amputations (LEAs) are a major cause of patient morbidity and mortality. The objectives of this study are to investigate the annual incidence of SSI and risk factors associated with SSI after LEA in diabetic patients. METHODS: LEAs performed on diabetic patients between 2005 and 2017 were retrospectively analyzed from the American College of Surgeons National Surgical Quality Improvement Program database. Incidence rates were calculated and analyzed for temporal change. Multivariable logistic regression was conducted to identify the independent predictors of SSIs in LEA. RESULTS: In 21,449 diabetic patients, the incidence of SSIs was 6.8% after LEA, with an overall decreasing annual trend (P = 0.013). Amputation location (below-knee in reference to above-knee) [OR (95% CI): 1.35 (1.20 - 1.53), P <0.001], smoking [OR (95% CI): 1.25 (1.11 - 1.41), P <0.001)], female sex [OR (95% CI): 1.16 (1.03 - 1.30)], preoperative sepsis [OR (95% CI): 1.24 (1.10 - 1.40), P <0.001], P = 0.013], emergency status [OR (95% CI): 1.38 (1.17 - 1.63), P <0.001], and obesity [OR (95% CI): 1.59 (1.12 - 2.27), P = 0.009] emerged as independent predictors of SSIs, while moderate/severe anemia emerged as a risk-adjusted protective factor [OR (95% CI): 0.75 (0.62 - 0.91), P = 0.003]. Sensitivity analysis found that moderate/severe anemia, not body mass index (BMI) class, remained a significant risk factor in the development of SSIs in below-the-knee amputations; in contrast, higher BMI, not preoperative hematocrit, was significantly associated with an increased risk for SSI in above-the-knee amputations. CONCLUSIONS: The incidence of SSIs after LEA in diabetic patients is decreasing. Overall, below-knee amputation, smoking, emergency status, and preoperative sepsis appeared to be associated with SSIs. Obesity increased SSIs in above-the-knee amputations, while moderate/severe preoperative anemia appears to protect against below-the-knee SSIs. Surgeons should take predictors of SSI into consideration while optimizing care for their patients, and future studies should investigate the role of preoperative hematocrit correction and how it may influence outcomes positively or negatively.

Hypoalbuminemia is Associated with Mortality in Patients Undergoing Lower Extremity Amputation.

BACKGROUND: Poor nutritional status is common among patients undergoing lower extremity amputation (LEA). In this study, the association between preoperative hypoalbuminemia, a marker for malnutrition, and postoperative mortality in patients undergoing LEA was explored. METHODS: Data on patients undergoing LEA between 2005 and 2017 were retrospectively analyzed from the prospectively collected American College of Surgeons National Surgical Quality Improvement Program database. Patients were divided into clinically relevant categories based on their serum albumin level (<2.5, 2.5-3.39, ≥3.4 g/dl) and were further stratified according to amputation level. Operative death was compared across groups and multivariable logistic regression was performed to estimate risk-adjusted odds ratio (AOR). RESULTS: In 35,383 patients, the rate of 30-day postoperative mortality was 7.6% (n = 2693). Mortality rate was highest in patients with very low albumin levels (11%) as compared to low (6.8%) and normal levels (3.9%). On multivariable analysis, lower albumin levels emerged as a risk-adjusted independent predictor of mortality. After risk-adjustment, patients with very low albumin levels (AOR [95% CI]: 2.25 [1.969-2.56], P < 0.001) and low albumin levels (AOR [95% CI]: 1.42 [1.239-1.616], P < 0.001) had higher odds of mortality when compared to patients with normal albumin levels. On sensitivity analysis, a similar trend was seen in patients undergoing above knee amputation but not in patients undergoing minor amputations. CONCLUSIONS: In patients undergoing major LEA, hypoalbuminemia is associated with an increased risk of postoperative mortality in a dose response manner, specifically in above knee amputations. Monitoring and optimizing patients' nutritional status before surgery, when possible, may be warranted and should be further explored.

Position Paper on Young Vascular Surgeons Training of the Mediterranean Federation for the Advancing of Vascular Surgery (MeFAVS): State of the Art and Perspectives.

The Mediterranean Federation for the Advancing of Vascular Surgery (MeFAVS) was founded in 2018, with the aim to promote cooperation among vascular professionals within Mediterranean countries. Due to its prominent social and economic impact on national health systems, diabetic peripheral artery was selected as the very first topic to be investigated by the federation. In this second paper, different experiences from delegates of participating countries were shared to define common strategies to harmonize, standardize, and optimize education and training in the Vascular Surgery specialty.

Citrobacter koseri Surgical Site Infection after Femoropopliteal Vein Bypass for Popliteal Artery Aneurysm Treated with a Graft Preserving Strategy.

Background: A 69-year-old man underwent ligation and evacuation of a popliteal artery aneurysm with a femoral-to-popliteal vein bypass. He had a history of Citrobacter koseri prostatitis two months prior to the surgery. One month postoperatively, he presented with extremity swelling, redness, and fluid collections around the graft. Methods: A graft preserving strategy was adopted. The patient underwent operative drainage, washing, and received long-term antibiotic therapy. Fluid culture grew Citrobacter koseri, previously not reported as cause of surgical site infection with infrainguinal graft involvement. Results: The infection was treated successfully, and the patient is remains symptom free 18 months post-operatively. Conclusions: This case highlights the importance of considering culturing the aneurysm content in the presence of infectious history.

Performance of the AUB-HAS2 Cardiovascular Risk Index in vascular surgery patients.

The American University of Beirut (AUB)-HAS2 risk index is a recently published tool for preoperative cardiovascular evaluation. It is based on six data elements: history of Heart disease, symptoms of Heart disease (angina or dyspnea), Age ⩾ 75 years, Anemia (hemoglobin < 12 mg/dL), emergency Surgery, and vascular Surgery. This study analyzes the performance of a modified AUB-HAS2 index (excluding the vascular surgery element) in a broad spectrum of vascular surgery procedures. The study population consisted of 90,476 vascular surgeries registered in the American College of Surgeons National Surgical Quality Improvement Program database. The performance of the AUB-HAS2 index was studied in seven groups: carotid endarterectomy (CEA), open abdominal aortic aneurysm surgical repair (OAAA), endovascular aortic aneurysm repair, supra-inguinal bypass, infra-inguinal bypass, lower extremity thrombo-endarterectomy, and lower extremity angioplasty. The outcome measure was death, myocardial infarction, or stroke at 30 days after surgery. Each patient was given an AUB-HAS2 score of 0, 1, 2, or > 2 depending on the number of data elements s/he has. The AUB-HAS2 index was able to stratify risk in the majority of patients into low (< 3%, score 0), intermediate (3-10%, score 1-2), and high (> 10%, score > 2) (p < 0.0001). The receiver operating curve had an area of 0.71 in the overall group and it ranged from 0.60 in CEA patients to 0.75 in OAAA patients. In conclusion, the AUB-HAS2 index is a simple tool that can quickly and effectively stratify the risk of patients undergoing a broad spectrum of vascular surgeries into low, intermediate, and high.

Major lower extremity amputations in a developing country: 10-Year experience at a tertiary medical center.

BACKGROUND: Lower extremity amputation (LEA) is a major surgical procedure with a high risk of significant morbidity and mortality. The objective of this study was to describe mortality and functionality outcomes following this procedure in a developing country. METHODS: This is a retrospective study of all patients undergoing LEA for non-traumatic etiology between 2007 and 2017. Medical records were used to retrieve demographics, comorbidities, and perioperative complications of identified patients. Patients were contacted to follow-up on their medical, postoperative care, and ambulatory status. Mortality and postoperative functionality rates were analyzed. RESULTS: The study included 78 patients. Median follow-up duration was 24 months. Hypertension (81%) and diabetes (79%) were the most common comorbidities. Mortality rates at 30 days, 1, and 5 years were 10.3, 29.2, and 65.5%, respectively. Mortality was significantly associated with age > 70 at amputation (p = 0.042), hypertension (p = 0.003), chronic kidney disease (p = 0.031), and perioperative sepsis (p = 0.01). Only 1.6% of patients were discharged into a specialized care center, and only 27% of patients were ambulatory postoperatively, although 90.5% were fitted with a prosthesis. CONCLUSIONS: Survival following major amputation in a developing country is currently comparable to more developed regions of the world. Major discrepancy seems to exist in ambulatory status following the procedure. Discharge placement policies should be properly set, and rehabilitation centers funding should be increased. Awareness may also be warranted to educate patients and families about the value and positive impact of rehabilitation centers.

Management of dual traumatic arterial-venous fistula from a single shotgun injury: a case report and literature review.

BACKGROUND: Traumatic arteriovenous fistula (TAVF) is an uncommon vascular entity that arises in various locations, often from penetrating injuries, with a wide spectrum of signs and symptoms. This case report highlights the importance of suspecting multiple TAVFs after a single gunshot wound, especially if it involves pellets. It also sheds light on adapting treatment, whether endovascular or open repair, to the location and characteristics of each fistula. CASE PRESENTATION: A 35-year-old male, with history of shotgun wound 5 months earlier, presented to our clinic with right lower extremity (RLE) edema and pain. Arterial duplex scan and subsequent angiogram showed two TAVFs at the popliteal and posterior tibial (PT) arteries, both of which could not be exactly localized with a computed tomography angiography (CTA) due to artifacts. The fistula connecting the posterior tibial artery (PTA) and vein was repaired endovascularly using a covered-stent, while the fistula between the popliteal artery and vein was repaired surgically. Postoperative follow-up at 3 months showed no arteriovenous fistula (AVF), patent vessels and distal stent stenosis at the PTA. CONCLUSIONS: Patients who sustain gunshot injuries with shrapnel or pellets and develop TAVF consequentially need to be followed up with the possibility of multiple AVFs in mind. Arterial duplex scan is highly sensitive to detect those AVFs, yet angiography remains gold standard, particularly with extensive metal artefacts. Endovascular repair, when feasible, should be considered first, unless the patient is unstable or has anatomical constraints that increase the risk of complications. Lastly, surgeons should be weary of deep venous thrombosis (DVT), the Branham effect and arterial aneurysmal dilation postoperatively.

Microbiological profile and antimicrobial resistance among diabetic foot infections in Lebanon.

Diabetic Foot Infection (DFI) is a challenging complication of diabetes mellitus with a high burden in the Middle East where there is a marked increase in diabetes prevalence and complications. Early detection of DFI and the infectious organisms could result in the early initiation of appropriate antibiotic therapy and improved outcomes. DFI microbiological profiles differ between countries. In our region, Western guidelines are used when initiating treatment for DFI in the absence of local guidance. The purpose of our study was to determine the microbiologic profile and antimicrobial susceptibility of the DFI admissions at a large tertiary referral centre in Beirut and review other reported series in Lebanon and our region. This is a retrospective observational study of patients with DFI admitted to the American University of Beirut Medical Centre from January 2008 to June 2017. The bacteriologic isolation and antimicrobial susceptibility tests were performed according to standard microbiological methods. Between 2008 and 2017, 319 diabetic patients with DFU were admitted to AUBMC, and deep-tissue cultures were taken for 179 patients. From 179 deep tissue cultures, 314 bacterial isolates were obtained. Fifty-four percent of patients had the polymicrobial infection. Aerobic gram-negative rods (GNR) were more prevalent than gram-positive cocci (GPC) (55%, 39%, respectively). The most common isolate was Escherichia coli (15%) followed by Enterococcus (14%) and Pseudomonas aeruginosa (11%). Staphylococcus aureus isolates accounted for 9% with 50% of them being methicillin-resistant (MRSA). Among Enterobacteriaceae, 37% of isolates were fluoroquinolone-resistant, 25% were ESBL producers, and 2% were carbapenem-resistant. Antibiotic resistance was significantly associated with prior usage of antibiotics. Anaerobes were isolated in 1% and Candida species in 5% of isolates. The sensitivity, specificity, PPV, and NPV of swab culture recovery of pathogens compared with deep tissue culture were (76%, 72%, 76%, 72%) and (94%, 81%, 91%, 86%) for gram-positive and gram-negative organisms, respectively. The microbiological profile of DFI in Lebanon is comparable to other countries in the MENA region with big differences compared with the West. Therefore, it is imperative to develop local guidelines for antimicrobial treatment. The high prevalence of GNR in DFI and the high fluoroquinolone resistance should be taken into consideration when choosing empiric antibiotics. Empiric treatment for MRSA or Pseudomonas does not appear necessary except for patients with specific risk factors.

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.

Bilateral Carotid Patch Infection Occurring 12 years Following Endarterectomy.

BACKGROUND: Carotid endarterectomy (CEA) is the most commonly used invasive procedure for treatment of carotid stenosis. Different methods are used to close the arteriotomy including primary closure and patch repair with a graft. Prosthetic patch infection is a rare but serious complication of patch closure, and we will present a unique case of carotid patch infection (CPI) 12 years after implantation. CASE: Patient is 76-year-old male ex-smoker with history of bilateral CEA with Dacron patch closure 12 years prior to presentation. He had a left neck draining sinus one year prior to presentation that was treated by patch excision and ICA ligation. He presented to us one year later with a right neck draining sinus tract, reaching the carotid sheath on CT scan. Surgery was done under EEG and NIRS oximetry with shunting. Excision of the patch with the involved ICA was done. CCA to distal ICA bypass was done by a reversed GSV graft. Intraoperative cultures of the patch grew Staphylococcus species coagulase negative, so the patient was discharged on antibiotics for one month. The patient had early postoperative swallowing difficulty that resolved over six weeks but no other complications. Patient was followed-up every three months and he was doing well on one-year follow-up. DISCUSSION: Carotid patch infection is a well-documented complication of CEA with a prevalence between 0.27% and 1%. It most commonly presents as a pseudoaneurysm, draining sinus or neck swelling. The highest incidence is during the first year after the operation, and especially within the first three months postop due to contamination or wound infections; however, late presentations such as our case are rare. Bacterial cultures are positive in around 80% of the cases, growing mostly gram-positive cocci. Other organisms include Pseudomonas and Enterobacter. Management of CPI is challenging; difficulties include distal ICA control, friable arteries and adhesions to cranial nerves. Debridement with ligation of the vessel stump is an option, but may not be tolerated. Best outcomes are obtained with autogenous revascularization after debridement as was done in our case on the right side. Newer endovascular techniques may provide alternatives in urgent or high-risk situations, especially as staged procedures. This case is unique in its bilaterality and the longest time till presentation in the literature.