Recommendations of the Blue Ribbon Committee II for the Optimization of Surgical Education and Training in the United States: The Surgical Trainee Perspective.

OBJECTIVE: This study aims to appraise recommendations from an expert panel of surgical educators on optimizing surgical education and training in the setting of contemporary challenges. BACKGROUND: The Blue Ribbon Committee (BRC II), a group of surgical educators, was convened to make recommendations to optimize surgical training considering the current changes in the landscape of surgical education. Surgical trainees were recruited to assess their impressions of the recommendations. METHODS: A mixed-methods study design was employed, with a survey, followed by focus group interviews. Participating residents and fellows were recruited through a purposeful sampling approach. Descriptive statistics were applied to analyze the survey data, and a thematic data analysis on interview transcripts was employed. RESULTS: The majority of trainee respondents (n=16) thought that all of the subcommittee recommendations should be included in the final BRC II recommendations and paper. According to the interviews, overall, the feedback from the trainees was positive, with particular excitement around work-life integration, education support and faculty development, and funding pitfalls. Some themes about concerns included a lack of clarity about the recommendations, concern about some recommendations being in conflict with one another, and a disconnect between the initial BRC II survey and the subsequent recommendations. CONCLUSIONS: The residents gathered for this focus group were encouraged by the thought, effort, and intention that gathered the surgical leaders across the country to make the recommendations. While there were areas the trainees wanted clarity on, the overall opinion was in agreement with the recommendations.

Volumetric analysis of acute uncomplicated type B aortic dissection using an automated deep learning aortic zone segmentation model.

BACKGROUND: Machine learning techniques have shown excellent performance in three-dimensional medical image analysis, but have not been applied to acute uncomplicated type B aortic dissection (auTBAD) using Society for Vascular Surgery (SVS) and Society of Thoracic Surgeons (STS)-defined aortic zones. The purpose of this study was to establish a trained, automatic machine learning aortic zone segmentation model to facilitate performance of an aortic zone volumetric comparison between patients with auTBAD based on the rate of aortic growth. METHODS: Patients with auTBAD and serial imaging were identified. For each patient, imaging characteristics from two computed tomography (CT) scans were analyzed: (1) the baseline CT angiography (CTA) at the index admission and (2) either the most recent surveillance CTA or the most recent CTA before an aortic intervention. Patients were stratified into two comparative groups based on aortic growth: rapid growth (diameter increase of ≥5 mm/year) and no or slow growth (diameter increase of <5 mm/year). Deidentified images were imported into an open source software package for medical image analysis and images were annotated based on SVS/STS criteria for aortic zones. Our model was trained using four-fold cross-validation. The segmentation output was used to calculate aortic zone volumes from each imaging study. RESULTS: Of 59 patients identified for inclusion, rapid growth was observed in 33 patients (56%) and no or slow growth was observed in 26 patients (44%). There were no differences in baseline demographics, comorbidities, admission mean arterial pressure, number of discharge antihypertensives, or high-risk imaging characteristics between groups (P > .05 for all). Median duration between baseline and interval CT was 1.07 years (interquartile range [IQR], 0.38-2.57). Postdischarge aortic intervention was performed in 13 patients (22%) at a mean of 1.5 ± 1.2 years, with no difference between the groups (P > .05). Among all patients, the largest relative percent increases in zone volumes over time were found in zone 4 (13.9%; IQR, -6.82 to 35.1) and zone 5 (13.4%; IQR, -7.78 to 37.9). There were no differences in baseline zone volumes between groups (P > .05 for all). The average Dice coefficient, a performance measure of the model output, was 0.73. Performance was best in zone 5 (0.84) and zone 9 (0.91). CONCLUSIONS: We describe an automatic deep learning segmentation model incorporating SVS-defined aortic zones. The open source, trained model demonstrates concordance to the manually segmented aortas with the strongest performance in zones 5 and 9, providing a framework for further clinical applications. In our limited sample, there were no differences in baseline aortic zone volumes between patients with rapid growth and patients with no or slow growth.

Comparative outcomes of open mesenteric bypass after a failed endovascular or open mesenteric revascularization for chronic mesenteric ischemia.

INTRODUCTION: Clinical practice guidelines have recommended an endovascular-first approach (ENDO) for the management of patients with chronic mesenteric ischemia (CMI), whereas an open mesenteric bypass (OMB) is proposed for subjects deemed to be poor ENDO candidates. However, the impact of a previous failed endovascular or open mesenteric reconstruction on a subsequent OMB is unknown. Accordingly, this study was designed to examine the results of a remedial OMB (R-OMB) after a failed ENDO or a primary OMB (P-OMB) for patients with recurrent CMI. METHODS: All patients who underwent an OMB from 2002 to 2022 at the University of Florida were reviewed. Outcomes after an R-OMB (ie, history of a failed ENDO or P-OMB) and P-OMB were compared. The primary end point was 30-day mortality, whereas secondary outcomes included complications, reintervention, and survival. The Kaplan-Meier methodology was used to estimate freedom from reintervention and all-cause mortality, whereas multivariable Cox proportional hazards modeling identified predictors of death. RESULTS: A total of 145 OMB procedures (R-OMB, n = 48 [33%]; P-OMB, n = 97 [67%]) were analyzed. A majority of R-OMB operations were performed for a failed stent (prior ENDO, n = 39 [81%]; prior OMB, n = 9 [19%]). R-OMB patients were generally younger (66 ± 9 years vs P-OMB, 69 ± 11 years; P = .09) and had lower incidence of smoking exposure (29% vs P-OMB, 48%; P = .07); however, there were no other differences in demographics or comorbidities. R-OMB was associated with less intraoperative transfusion (0.6 units vs P-OMB, 1.4 units; P = .01), but there were no differences in conduit choice or bypass configuration.The overall 30-day mortality and complication rates were 7% (n = 10/145) and 53% (n = 77/145), respectively, with no difference between the groups. Notably, R-OMB had decreased cardiac (6% vs P-OMB, 21%; P < .01) and bleeding complication rates (2% vs P-OMB, 15%; P = .01). The freedom from reintervention (1 and 5 years: R-OMB: 95% ± 4%, 83% ± 9% vs P-OMB: 97% ± 2%, 93% ± 5%, respectively; log-rank P = .21) and survival (1 and 5 years: R-OMB: 82% ± 6%, 68% ± 9% vs P-OMB: 84% ± 4%, 66% ± 7%; P = .91) were similar. Independent predictors of all-cause mortality included new postoperative hemodialysis requirement (hazard ratio [HR], 7.4, 95% confidence interval [CI], 3.1-17.3; P < .001), pulmonary (HR, 2.7, 95% CI, 1.4-5.3; P = .004) and cardiac (HR, 2.4, 95% CI, 1.1-5.1; P = .04) complications, and female sex (HR, 2.1, 95% CI, 1.03-4.8; P = .04). Notably, R-OMB was not a predictor of death. CONCLUSIONS: The perioperative and longer-term outcomes for a remedial OMB after a failed intraluminal stent or previous open bypass appear to be comparable to a P-OMB. These findings support the recently updated clinical practice guideline recommendations for an endovascular-first approach to treating recurrent CMI due to the significant perioperative complication risk of OMB. However, among the subset of patients deemed ineligible for endoluminal reconstruction after failed mesenteric revascularization, R-OMB results appear to be acceptable and highlight the utility of this strategy in selected patients.

Persistent Acute Kidney Injury is Associated with Poor Outcomes and Increased Hospital Cost in Vascular Surgery.

BACKGROUND: Postoperative acute kidney injury (AKI) is common after major surgery and is associated with increased morbidity, mortality, and cost. Additionally, there are recent studies demonstrating that time to renal recovery may have a substantial impact on clinical outcomes. We hypothesized that patients with delayed renal recovery after major vascular surgery will have increased complications, mortality, and hospital cost. METHODS: A single-center retrospective cohort of patients undergoing nonemergent major vascular surgery between 6/1/2014 and 10/1/2020 was analyzed. Development of postoperative AKI (defined using Kidney Disease Improving Global Outcomes (KDIGO) criteria: >50% or > 0.3 mg/dl absolute increase in serum creatinine relative to reference after surgery and before discharge) was evaluated. Patients were divided into 3 groups: no AKI, rapidly reversed AKI (<48 hours), and persistent AKI (≥48 hours). Multivariable generalized linear models were used to evaluate the association between AKI groups and postoperative complications, 90-day mortality, and hospital cost. RESULTS: A total of 1,881 patients undergoing 1,980 vascular procedures were included. Thirty five percent of patients developed postoperative AKI. Patients with persistent AKI had longer intensive care unit and hospital stays, as well as more mechanical ventilation days. In multivariable logistic regression analysis, persistent AKI was a major predictor of 90-day mortality (odds ratio 4.1, 95% confidence interval 2.4-7.1). Adjusted average cost was higher for patients with any type of AKI. The incremental cost of having any AKI ranged from $3,700 to $9,100, even after adjustment for comorbidities and other postoperative complications. The adjusted average cost for patients stratified by type of AKI was higher among patients with persistent AKI compared to those with no or rapidly reversed AKI. CONCLUSIONS: Persistent AKI after vascular surgery is associated with increased complications, mortality, and cost. Strategies to prevent and aggressively treat AKI, specifically persistent AKI, in the perioperative setting are imperative to optimize care for this population.

Outcomes of Patients with Acute Type B Aortic Dissection and High-Risk Features.

BACKGROUND: Recently the Society for Vascular Surgery (SVS) and Society for Thoracic Surgeons (STS) published contemporary guidelines clearly defining complicated versus uncomplicated acute type B aortic dissections (TBADs) with an additional high-risk grouping. Few studies have evaluated outcomes associated with "high-risk" TBADs. The objective of this study was to assess differences in demographics, clinical presentation, symptom onset, and outcomes in high-risk patients that underwent either thoracic endovascular aortic repair (TEVAR) or best medical management for acute TBAD compared to those with complicated and uncomplicated acute TBAD. METHODS: Patients admitted with acute TBADs from a single academic medical center from October 2011 to March 2020 were analyzed. Per the STS/SVS 2020 guidelines, high risk was defined as refractory pain/hypertension, bloody pleural effusion, aortic diameter >4 cm, false lumen diameter >22 mm, radiographic malperfusion, and early readmission, and complicated was defined as ruptured/malperfusion presentation. Uncomplicated patients were those without malperfusion/rupture and without high-risk features. The primary end-point was inpatient mortality. Secondary end-points included complications, reintervention, and survival. RESULTS: Of the 159 patients identified with acute TBAD, 63 (40%) met the high-risk criteria. In the high-risk cohort, 38 (60%) underwent TEVAR (HR-TEVAR), with refractory pain as the most common indication, while 25 (40%) were managed medically (HR-medical). Malperfusion or rupture was present in 63 (40%) patients (complicated TBAD (C-TBAD)), all of whom underwent TEVAR. An additional 33 patients had no high-risk features and were all managed medically (uncomplicated TBAD). There were no differences in age, body mass index, and race between groups. Among the 4 groups, there were variable distributions in sex, insurance status, and incidence of several baseline comorbidities including congestive heart failure, chronic obstructive pulmonary disease, and renal dysfunction (P < 0.05 for all). C-TBAD had increased length of stay (12, interquartile range [IQR] 9-22) compared to HR-TEVAR (11.5, IQR 7-15), HR-medical (6, IQR 5-8), and uncomplicated TBAD (7, IQR 5-10) (P < 0.01). C-TBAD had decreased days from admission to repair (0, IQR 0-2) compared to HR-TEVAR (3.5, IQR 1-8) (P < 0.01). C-TBAD patients had worse 3-year survival compared to other groups (log-rank P < 0.01), although when in-hospital mortality was excluded, survival was similar among groups (P = 0.37). Of patients initially managed medically, outpatient TEVAR was performed in 6 (24%) HR-medical and 4 (12%) uncomplicated patients, with no difference between rate of intervention between groups (P = 0.22). CONCLUSIONS: High-risk features, as defined in updated SVS/STS guidelines, are common in patients presenting with acute TBAD. High-risk patients had acceptable outcomes when managed either surgically or medically. High-risk patients that underwent TEVAR had improved perioperative outcomes and mortality compared to those undergoing TEVAR for C-TBAD, a finding which may help guide preoperative risk stratification and patient counseling.

Sarcopenia is a Poor Predictor of Outcomes in Elective Colectomy for Diverticulitis.

BACKGROUND: Sarcopenia is associated with adverse perioperative outcomes in patients undergoing operations for malignancy, but its influence on patients undergoing elective colectomy for diverticulitis is unknown. We hypothesized that sarcopenia is associated with adverse perioperative events in patients undergoing elective colectomy for diverticulitis. METHODS: Comorbidities, operative characteristics, and postoperative complications were extrapolated from our institutional EMR in patients undergoing elective colectomy for diverticulitis from 2016 to 2020. Sarcopenia was calculated using perioperative imaging and defined by standard skeletal muscle index (SMI) and psoas muscle index (PMI) thresholds. Univariate analysis was used to compare sarcopenic and non-sarcopenic patients. RESULTS: 148 patients met inclusion criteria. Using SMI thresholds, 95 patients (64%) were sarcopenic. With SMI criteria, sarcopenic patients were older (67 vs 52 years old; P < .01) and had lower BMIs (26.2 vs 34.0, respectively; P < .001) than non-sarcopenic patients. There were no differences in baseline characteristics, postoperative complications, and non-home discharge between groups (P > .05 for all). Postoperative length of stay was greater in sarcopenic patients (3 IQR 2-5 vs 2 IQR 2-3 days; P < .01). Using PMI thresholds, 68 (46%) met criteria for sarcopenia. Using PMI thresholds, sarcopenic patients were older (68 vs 57.5 years old; P < .01) and had lower BMIs (25.8 vs 32.8; P < .01). There were no differences in comorbidities or measured operative outcomes between groups (P > .05 for all), other than postoperative length of stay which was longer in the sarcopenic group (3.5 IQR 3-5 vs 2 IQR 2-3; P < .01). CONCLUSIONS: Incidence of sarcopenia was high in patients undergoing elective colectomy for diverticulitis in our practice, but sarcopenia was not associated with adverse perioperative outcomes. In select patients, elective colectomy for diverticulitis can be safely performed in the presence of sarcopenia.

Short-Term Dietary Restriction Potentiates an Anti-Inflammatory Circulating Mucosal-Associated Invariant T-Cell Response.

Short-term protein-calorie dietary restriction (StDR) is a promising preoperative strategy for modulating postoperative inflammation. We have previously shown marked gut microbial activity during StDR, but relationships between StDR, the gut microbiome, and systemic immunity remain poorly understood. Mucosal-associated invariant T-cells (MAITs) are enriched on mucosal surfaces and in circulation, bridge innate and adaptive immunity, are sensitive to gut microbial changes, and may mediate systemic responses to StDR. Herein, we characterized the MAIT transcriptomic response to StDR using single-cell RNA sequencing of human PBMCs and evaluated gut microbial species-level changes through sequencing of stool samples. Healthy volunteers underwent 4 days of DR during which blood and stool samples were collected before, during, and after DR. MAITs composed 2.4% of PBMCs. More MAIT genes were differentially downregulated during DR, particularly genes associated with MAIT activation (CD69), regulation of pro-inflammatory signaling (IL1, IL6, IL10, TNFα), and T-cell co-stimulation (CD40/CD40L, CD28), whereas genes associated with anti-inflammatory IL10 signaling were upregulated. Stool analysis showed a decreased abundance of multiple MAIT-stimulating Bacteroides species during DR. The analyses suggest that StDR potentiates an anti-inflammatory MAIT immunophenotype through modulation of TCR-dependent signaling, potentially secondary to gut microbial species-level changes.

Mitochondrial targeted catalase improves muscle strength following arteriovenous fistula creation in mice with chronic kidney disease.

Hand dysfunction is a common observation after arteriovenous fistula (AVF) creation for hemodialysis access and has a variable clinical phenotype; however, the underlying mechanism responsible is unclear. Grip strength changes are a common metric used to assess AVF-associated hand disability but has previously been found to poorly correlate with the hemodynamic perturbations post-AVF placement implicating other tissue-level factors as drivers of hand outcomes. In this study, we sought to test if expression of a mitochondrial targeted catalase (mCAT) in skeletal muscle could reduce AVF-related limb dysfunction in mice with chronic kidney disease (CKD). Male and female C57BL/6J mice were fed an adenine-supplemented diet to induce CKD prior to placement of an AVF in the iliac vascular bundle. Adeno-associated virus was used to drive expression of either a green fluorescent protein (control) or mCAT using the muscle-specific human skeletal actin (HSA) gene promoter prior to AVF creation. As expected, the muscle-specific AAV-HSA-mCAT treatment did not impact blood urea nitrogen levels (P = 0.72), body weight (P = 0.84), or central hemodynamics including infrarenal aorta and inferior vena cava diameters (P > 0.18) or velocities (P > 0.38). Hindlimb perfusion recovery and muscle capillary densities were also unaffected by AAV-HSA-mCAT treatment. In contrast to muscle mass and myofiber size which were not different between groups, both absolute and specific muscle contractile forces measured via a nerve-mediated in-situ preparation were significantly greater in AAV-HSA-mCAT treated mice (P = 0.0012 and P = 0.0002). Morphological analysis of the post-synaptic neuromuscular junction uncovered greater acetylcholine receptor cluster areas (P = 0.0094) and lower fragmentation (P = 0.0010) in AAV-HSA-mCAT treated mice. Muscle mitochondrial oxidative phosphorylation was not different between groups, but AAV-HSA-mCAT treated mice had lower succinate-fueled mitochondrial hydrogen peroxide emission compared to AAV-HSA-GFP mice (P < 0.001). In summary, muscle-specific scavenging of mitochondrial hydrogen peroxide significantly improves neuromotor function in mice with CKD following AVF creation.