Transcriptomic and Proteomic Characterization of the Immune Response to Elective Spinal Reconstructive Surgery: Impact of Aging and Comparison with Traumatic Injury Response

BACKGROUND

Major surgery triggers trauma-like stress responses linked to age, surgery duration, and blood loss, resembling polytrauma. This similarity suggests elective surgery as a surrogate model for studying polytrauma immune responses. We investigated stress responses across age groups and compared them with those of polytrauma patients.

STUDY DESIGN

Patients undergoing major spinal reconstruction surgery were divided into older (age >65 years, n = 5) and young (age 18 to 39 years, n = 6) groups. A comparison group consisted of matched trauma patients (n = 8). Blood samples were collected before, during, and after surgery. Bone marrow mononuclear cells and peripheral blood mononuclear cells were analyzed using cellular indexing of transcriptomes and epitopes sequencing or single-cell RNA sequencing. Plasma was subjected to dual-platform proteomic analysis (SomaLogic and O-link).

RESULTS

Response to polytrauma was highest within 4 hours. By comparison, the response to surgery was highest at 24 hours. Both insults triggered significant changes in cluster of differentiation 14 monocytes, with increased inflammation and lower major histocompatibility complex-class 2 expression. Older patient's cluster of differentiation 14 monocytes displayed higher inflammation and less major histocompatibility complex-class 2 suppression; a trend was also seen in bone marrow mononuclear cells. Although natural killer cells were markedly activated after polytrauma, they were suppressed after surgery, especially in older patients. In plasma, innate immunity proteins dominated at 24 hours, shifting to adaptive immunity proteins by 6 weeks with heightened inflammation in older patients. Senescence-associated secretory phenotype proteins were higher in older patients at baseline and further elevated during and after surgery.

CONCLUSIONS

Although both major surgery and polytrauma initiate immune and stress responses, substantial differences exist in timing and cellular profiles, suggesting major elective surgery is not a suitable surrogate for the polytrauma response. Nonetheless, distinct responses in young vs older patients highlight the utility of elective spinal in studying patient-specific factors affecting outcomes after major elective surgery.

Percutaneous thrombectomy for acute limb ischemia is associated with equivalent limb and mortality outcomes compared with open thrombectomy

BACKGROUND

Acute limb ischemia (ALI) carries a 15% to 20% risk of combined death or amputation at 30 days and 50% to 60% at 1 year. Percutaneous mechanical thrombectomy (PT) is an emerging minimally invasive alternative to open thrombectomy (OT). However, ALI thrombectomy cases are omitted from most quality databases, limiting comparisons of limb and survival outcomes between PT and OT. Therefore, our aim was to compare in-hospital outcomes between PT and OT using the National Inpatient Sample.

METHODS

We analyzed survey-weighted National Inpatient Sample data (2015-2020) to include emergent admissions of aged adults (50+ years) with a primary diagnosis of lower extremity ALI undergoing index procedures within 2 days of hospitalization. We excluded hospitalizations with concurrent trauma or dissection diagnoses and index procedures using catheter-directed thrombolysis. Our primary outcome was composite in-hospital major amputation or death. Secondary outcomes included in-hospital major amputation, death, in-hospital reintervention (including angioplasty/stent, thrombolysis, PT, OT, or bypass), and extended length of stay (eLOS; defined as LOS >75th percentile). Adjusted odds ratios (aORs) with 95% confidence intervals (95% CIs) were generated by multivariable logistic regression, adjusting for demographics, frailty (Risk Analysis Index), secondary diagnoses including atrial fibrillation and peripheral artery disease, hospital characteristics, and index procedure data including the anatomic thrombectomy level and fasciotomy. A priori subgroup analyses were performed using interaction terms.

RESULTS

We included 23,795 survey-weighted ALI hospitalizations (mean age: 72.2 years, 50.4% female, 79.2% White, and 22.3% frail), with 7335 (30.8%) undergoing PT. Hospitalization characteristics for PT vs OT differed by atrial fibrillation (28.7% vs 36.5%, P < .0001), frequency of intervention at the femoropopliteal level (86.2% vs 88.8%, P = .009), and fasciotomy (4.8% vs 6.9%, P = .006). In total, 2530 (10.6%) underwent major amputation or died. Unadjusted (10.1% vs 10.9%, P = .43) and adjusted (aOR = 0.96 [95% CI, 0.77-1.20], P = .74) risk did not differ between the groups. PT was associated with increased odds of reintervention (aOR = 2.10 [95% CI, 1.72-2.56], P < .0001) when compared with OT, but this was not seen in the tibial subgroup (aOR = 1.31 [95% CI, 0.86-2.01], P = .21, Pinteraction < .0001). Further, 79.1% of PT hospitalizations undergoing reintervention were salvaged with endovascular therapy. Lastly, PT was associated with significantly decreased odds of eLOS (aOR = 0.80 [95% CI, 0.69-0.94], P = .005).

CONCLUSIONS

PT was associated with comparable in-hospital limb salvage and mortality rates compared with OT. Despite an increased risk of reintervention, most PT reinterventions avoided open surgery, and PT was associated with a decreased risk of eLOS. Thus, PT may be an appropriate alternative to OT in appropriately selected patients.

The Association Between Frailty and Outcomes Following Ruptured Abdominal Aortic Aneurysm Repair

BACKGROUND

Endovascular aortic repair (EVAR) is a less invasive method than the more physiologically stressful open surgical repair (OSR) for patients with anatomically appropriate abdominal aortic aneurysm (AAA). Early postoperative outcomes are associated with both patients' physiologic reserve and the physiologic stresses of the surgical intervention. Among frail patients with reduced physiologic reserve, the stress of an aortic rupture in combination with the stress of an operative repair are less well tolerated, raising the risk of complications and mortality. This study aims to evaluate the difference in association between frailty and outcomes among patients undergoing minimally invasive EVAR and the physiologically more stressful OSR for ruptured AAA (rAAA).

STUDY DESIGN

Our retrospective cohort study included adults undergoing rAAA repair in the Vascular Quality Initiative from 2010 to 2022. The validated Risk Analysis Index (RAI; robust≤20, normal 21-29, frail 30-39, very frail≥40) quantified frailty. The association between the primary outcome of 1-year mortality and frailty status as well as repair type were compared using multivariable Cox models generating adjusted hazard ratios (aHR) with 95% confidence intervals (95%CI). Interaction terms evaluated the association's moderation.

RESULTS

We identified 5,806 patients (age 72±9 years; 77% male; EVAR 65%; robust 6%; normal 48%; frail 36%; very frail 10%) with a 53% observed 1-year mortality rate following rAAA repair. OSR [aHR = 1.43 (95%CI 1.19-1.73)] was associated with increased 1-year mortality when compared to EVAR. Increasing frailty status [frail aHR = 1.26 (95%CI 1.00-1.59); very frail aHR =1.64 (95%CI 1.26-2.13)] was associated with increased 1-year mortality, which was moderated by repair type (P-interaction<.05). OSR was associated with increased 1-year mortality in normal [aHR = 1.49 (95%CI 1.20-1.87)] and frail [aHR = 1.51 (95%CI 1.20-1.89)], but not among robust [aHR = 0.88 (95%CI 0.59-1.32)] and very frail [aHR = 1.29 (95%CI 0.97-1.72)] patients.

CONCLUSION

Frailty and OSR were associated with increased adjusted risk of 1-year mortality following rAAA repair. Among normal and frail patients, OSR was associated with an increased adjusted risk of 1-year mortality when compared to EVAR. However, there was no difference between OSR and EVAR among robust patients who can well-tolerate the stress of OSR and among very frail patients who are unable to withstand the surgical stress from rAAA regardless of repair type.

Socioeconomic factors predict successful supervised exercise therapy completion

OBJECTIVE

Supervised exercise therapy (SET) for patients with intermittent claudication (IC) can lower the risk of progression to chronic limb-threatening ischemia and amputation, while preserving and restoring functional status. Despite supporting evidence, it remains underutilized, and among those who initiate programs, attrition rates are extremely high. We hypothesize that socioeconomic factors may represent significant barriers to SET completion.

METHODS

Patients with IC referred to SET at a multi-hospital, single-institution health care system (2018-2022) from a prospectively maintained database were retrospectively analyzed. Our primary endpoint was SET program completion and graduation, defined as completion of 36 sessions. Our secondary endpoints were vascular intervention within 1 year of referral and change in ankle-brachial index (ABI). Baseline demographics were assessed using standard statistical methods. Predictors of SET graduation were analyzed using multivariable logistic regression generating adjusted odds ratios (aORs) with 95% confidence intervals (CIs). Change in ABI was analyzed using t-test between subgroups. Reasons for attrition were tabulated. Patient Health Questionnaire-9 (PHQ-9), metabolic equivalent level, Vascular QOL, Duke Activity Status, and ABI were analyzed using paired t-tests across the entire cohort.

RESULTS

Fifty-two patients met inclusion criteria: mean age 67.85 ± 10.69 years, 19 females (36.54%), mean baseline ABI of 0.77 ± 0.16. The co-pays for 100% of patients were fully covered by primary and secondary insurance plans. Twenty-one patients (40.38%) completed SET. On multivariable analysis, residence in a ZIP code with median household income <$47,000 (aOR, 0.10; 95% CI, 0.01-0.76; P = .03) and higher body mass index (aOR, 0.81; 95% CI, 0.67-0.99; P = .04) were significant barriers to SET graduation. There were no differences in ABI change or vascular intervention within 1 year between graduates and non-graduates. Non-graduates reported transportation challenges (25.00%), lack of motivation (20.83%), and illness/functional limitation (20.83%) as primary reasons for SET attrition. Metabolic Equivalent Level (P ≤ .01) and Duke Activity Status scores (P = .04) were significantly greater after participating in a SET program.

CONCLUSIONS

Although SET participation improves lower extremity and functionality outcomes, only 40% of referred patients completed therapy in our cohort. Our findings suggest that both socioeconomic and functional factors influence the odds of completing SET programs, indicating a need for holistic pre-referral assessment to facilitate enhanced program accessibility for these populations.

Hypertension during transfer is associated with poor outcomes in unstable patients with ruptured abdominal aortic aneurysm

OBJECTIVE

Limited data exist for optimal blood pressure (BP) management during transfer of patients with ruptured abdominal aortic aneurysm (rAAA). This study evaluates the effects of hypertension and severe hypotension during interhospital transfers in a cohort of patients with rAAA in hemorrhagic shock.

METHODS

We performed a retrospective, single-institution review of patients with rAAA transferred via air ambulance to a quaternary referral center for repair (2003-2019). Vitals were recorded every 5 minutes in transit. Hypertension was defined as a systolic BP of ≥140 mm Hg. The primary cohort included patients with rAAA with hemorrhagic shock (≥1 episode of a systolic BP of <90 mm Hg) during transfer. The primary analysis compared those who experienced any hypertensive episode to those who did not. A secondary analysis evaluated those with either hypertension or severe hypotension <70 mm Hg. The primary outcome was 30-day mortality.

RESULTS

Detailed BP data were available for 271 patients, of which 125 (46.1%) had evidence of hemorrhagic shock. The mean age was 74.2 ± 9.1 years, 93 (74.4%) were male, and the median total transport time from helicopter dispatch to arrival at the treatment facility was 65 minutes (interquartile range, 46-79 minutes). Among the cohort with shock, 26.4% (n = 33) had at least one episode of hypertension. There were no significant differences in age, sex, comorbidities, AAA repair type, AAA anatomic location, fluid resuscitation volume, blood transfusion volume, or vasopressor administration between the hypertensive and nonhypertensive groups. Patients with hypertension more frequently received prehospital antihypertensives (15% vs 2%; P = .01) and pain medication (64% vs 24%; P < .001), and had longer transit times (36.3 minutes vs 26.0 minutes; P = .006). Episodes of hypertension were associated with significantly increased 30-day mortality on multivariable logistic regression (adjusted odds ratio [aOR], 4.71; 95% confidence interval [CI], 1.54-14.39; P = .007; 59.4% [n = 19] vs 40.2% [n = 37]; P = .01). Severe hypotension (46%; n = 57) was also associated with higher 30-day mortality (aOR, 2.82; 95% CI, 1.27-6.28; P = .01; 60% [n = 34] vs 32% [n = 22]; P = .01). Those with either hypertension or severe hypotension (54%; n = 66) also had an increased odds of mortality (aOR, 2.95; 95% CI, 1.08-8.11; P = .04; 58% [n = 38] vs 31% [n = 18]; P < .01). Level of hypertension, BP fluctuation, and timing of hypertension were not significantly associated with mortality.

CONCLUSIONS

Hypertensive and severely hypotensive episodes during interhospital transfer were independently associated with increased 30-day mortality in patients with rAAA with shock. Hypertension should be avoided in these patients, but permissive hypotension approaches should also maintain systolic BPs above 70 mm Hg whenever possible.

Prophylactic defunctioning stomas improve clinical outcomes of anastomotic leak following rectal cancer resections: An analysis of the US Rectal Cancer Consortium

PURPOSE

Anastomotic leak (AL) is a complication of low anterior resection (LAR) that results in substantial morbidity. There is immense interest in evaluating immediate postoperative and long-term oncologic outcomes in patients who undergo diverting loop ileostomies (DLI). The purpose of this study is to understand the relationship between fecal diversion, AL, and oncologic outcomes.

METHODS

This is a retrospective multicenter cohort study using patient data obtained from the US Rectal Cancer Consortium database compiled from six academic institutions. The study population included patients with rectal adenocarcinoma undergoing LAR. The primary outcome was the incidence of AL among patients who did or did not receive DLI during LAR. Secondary outcomes included risk factors for AL, receipt of adjuvant therapy, 3-year overall survival, and 3-year recurrence.

RESULTS

Of 815 patients, 38 (4.7%) suffered AL after LAR. Patients with AL were more likely to be male, have unintentional preoperative weight loss, and are less likely to undergo DLI. On multivariable analysis, DLI remained protective against AL (p < 0.001). Diverted patients were less likely to undergo future surgical procedures including additional ostomy creation, completion proctectomy, or pelvic washout for AL. Subgroup analysis of 456 patients with locally advanced disease showed that DLI was correlated with increased receipt of adjuvant therapy for patients with and without AL on univariate analysis (SHR:1.59; [95% CI 1.19-2.14]; p = 0.002), but significance was not met in multivariate models.

CONCLUSION

Lack of DLI and preoperative weight loss was associated with anastomotic leak. Fecal diversion may improve the timely initiation of adjuvant oncologic therapy. The long-term outcomes following routine diverting stomas warrant further study.

Outcomes of Women Undergoing Noncardiac Surgery in Veterans Affairs Compared With Non-Veterans Affairs Care Settings

Importance

Recent legislation facilitates veterans' ability to receive non-Veterans Affairs (VA) surgical care. Although veterans are predominantly male, the number of women receiving care within the VA has nearly doubled to 10% over the past decade and recent data comparing the surgical care of women in VA and non-VA care settings are lacking.

Objective

To compare postoperative outcomes among women treated in VA hospitals vs private-sector hospitals.

Design, Setting, and Participants

This coarsened exact-matched cohort study across 9 noncardiac specialties in the Veterans Affairs Surgical Quality Improvement Program (VASQIP) and American College of Surgeons National Surgical Quality Improvement Program (NSQIP) took place from January 1, 2016, to December 31, 2019. Multivariable Poisson models with robust standard errors were used to evaluate the association between VA vs private-sector care settings and 30-day mortality. Hospitals participating in American College of Surgeons NSQIP and VASQIP were included. Data analysis was performed in January 2023. Participants included female patients 18 years old or older.

Exposures

Surgical care in VA or private-sector hospitals.

Main Outcomes and Measures

Postoperative 30-day mortality and failure to rescue (FTR).

Results

Among 1 913 033 procedures analyzed, patients in VASQIP were younger (VASQIP: mean age, 49.8 [SD, 13.0] years; NSQIP: mean age, 55.9 [SD, 16.9] years; P < .001) and although most patients in both groups identified as White, there were significantly more Black women in VASQIP compared with NSQIP (29.6% vs 12.7%; P < .001). The mean risk analysis index score was lower in VASQIP (13.9 [SD, 6.4]) compared with NSQIP (16.3 [SD, 7.8]) (P < .001 for both). Patients in the VA were more likely to have a preoperative acute serious condition (2.4% vs 1.8%: P < .001), but cases in NSQIP were more frequently emergent (6.9% vs 2.6%; P < .001). The 30-day mortality, complications, and FTR were 0.2%, 3.2%, and 0.1% in VASQIP (n = 36 762 procedures) as compared with 0.8%, 5.0%, and 0.5% in NSQIP (n = 1 876 271 procedures), respectively (all P < .001). Among 1 763 540 matched women (n = 36 478 procedures in VASQIP; n = 1 727 062 procedures in NSQIP), these rates were 0.3%, 3.7%, and 0.2% in NSQIP and 0.1%, 3.4%, and 0.1% in VASQIP (all P < .01). Relative to private-sector care, VA surgical care was associated with a lower risk of death (adjusted risk ratio [aRR], 0.41; 95% CI, 0.23-0.76). This finding was robust among women undergoing gynecologic surgery, inpatient surgery, and low-physiologic stress procedures. VA surgical care was also associated with lower risk of FTR (aRR, 0.41; 95% CI, 0.18-0.92) for frail or Black women and inpatient and low-physiologic stress procedures.

Conclusions and Relevance

Although women comprise the minority of veterans receiving care within the VA, in this study, VA surgical care for women was associated with half the risk of postoperative death and FTR. The VA appears better equipped to meet the unique surgical needs and risk profiles of veterans, regardless of sex and health policy decisions, including funding, should reflect these important outcome differences.

The Role of Integrated Air Transport System in Managing Abdominal Aortic Aneurysm Rupture Patients

OBJECTIVE

Ruptured abdominal aortic aneurysms (rAAAs) are highly morbid emergencies. Not all hospitals are equipped to repair them, and an air ambulance network may aid in regionalising speciality care to quaternary referral centres. The association of travel distance by air ambulance on rAAA mortality in patients transferred emergently for repair was examined.

METHODS

A retrospective review of institutional data. Adults with rAAA (2002 - 2019) transferred from an outside hospital (OSH) to a single quaternary referral centre for repair via air ambulance were identified. Patients who arrived via ground transport or post-repair at OSH for continued critical care were excluded. Patients were divided into "near" and "far" groups based on the 75th percentile of straight line travel distance (> 72 miles) between hospitals. The primary outcome was 30 day mortality. Multivariate logistic regression was used to assess the association of distance with mortality after adjusting for age, sex, race, cardiovascular comorbidities, and repair type.

RESULTS

A total of 290 patients with rAAA were transported a median distance of 40.4 miles (interquartile range 25.5, 72.7) with 215 (74.1%) near and 75 (25.9%) far patients. Both near and far groups had similar ages, sex, and race. There was no difference in pre-operative loss of consciousness, intubation, or cardiac arrest between groups. Endovascular aneurysm repair utilisation and intra-operative aortic occlusion balloon usage were also similar. Both observed (26.8% vs. 23.9%, p = .61) and adjusted odd ratio (0.70, 95% confidence interval 0.36 - 1.39, p = .32) 30 day mortality did not differ significantly between near and far groups.

CONCLUSION

Increasing distance travelled during transfer by air ambulance was not associated with worse outcomes in patients with rAAA. The findings support the regionalisation of rAAA repair to large quaternary centres via an integrated and robust air ambulance network.

A Prospective Cohort Protocol for the Remnant Investigation in Sepsis Study

BACKGROUND

Sepsis is a common and deadly syndrome, accounting for more than 11 million deaths annually. To mature a deeper understanding of the host and pathogen mechanisms contributing to poor outcomes in sepsis, and thereby possibly inform new therapeutic targets, sophisticated, and expensive biorepositories are typically required. We propose that remnant biospecimens are an alternative for mechanistic sepsis research, although the viability and scientific value of such remnants are unknown.

METHODS AND RESULTS

The Remnant Biospecimen Investigation in Sepsis study is a prospective cohort study of 225 adults (age ≥ 18 yr) presenting to the emergency department with community sepsis, defined as sepsis-3 criteria within 6 hours of arrival. The primary objective was to determine the scientific value of a remnant biospecimen repository in sepsis linked to clinical phenotyping in the electronic health record. We will study candidate multiomic readouts of sepsis biology, governed by a conceptual model, and determine the precision, accuracy, integrity, and comparability of proteins, small molecules, lipids, and pathogen sequencing in remnant biospecimens compared with paired biospecimens obtained according to research protocols. Paired biospecimens will include plasma from sodium-heparin, EDTA, sodium fluoride, and citrate tubes.

CONCLUSIONS

The study has received approval from the University of Pittsburgh Human Research Protection Office (Study 21120013). Recruitment began on October 25, 2022, with planned release of primary results anticipated in 2024. Results will be made available to the public, the funders, critical care societies, laboratory medicine scientists, and other researchers.

Characterization of multiple organ failure after ruptured abdominal aortic aneurysm repair

BACKGROUND

Multiple organ failure (MOF) is associated with poor outcomes and increased mortality in sepsis and trauma. There are limited data regarding MOF in patients after ruptured abdominal aortic aneurysm (rAAA) repair. We aimed to identify the contemporary prevalence and characteristics of patients with rAAA with MOF.

METHODS

We retrospectively reviewed patients with rAAA who underwent repair (2010-2020) at our multihospital institution. Patients who died within the first 2 days after repair were excluded. MOF was quantified by modified (excluding hepatic system) Denver, Sequential Organ Failure Assessment (SOFA) score, and Multiple Organ Dysfunction Score (MODS) for postoperative days 3 to 5 to determine the prevalence of MOF. MOF was defined as a Denver score of >3, dysfunction in two or more organ systems by SOFA score, or a MODS score of >8. Kaplan-Meier curves and log-rank testing were used to evaluate differences in 30-day mortality between multiple organ failure and patients without MOF. Logistic regression was used to assess predictors of MOF.

RESULTS

Of 370 patients with rAAA, 288 survived past two days (mean age, 73±10.1 years; 76.7% male; 44.1% open repair), and 143 had data for MOF calculation recorded. From postoperative days 3 to 5, 41 (14.24%) had MOF by Denver, 26 (9.03%) by SOFA, and 39 (13.54%) by MODS criteria. Among these scoring systems, pulmonary and neurological systems were impacted most commonly. Among patients with MOF, pulmonary derangement occurred in 65.9% (Denver), 57.7% (SOFA), and 56.4% (MODS). Similarly, neurological derangement occurred in 92.3% (SOFA) and 89.7% (MODS), but renal derangement occurred in 26.8% (Denver), 23.1% (SOFA), and 10.3% (MODS). MOF by all three scoring systems was associated with increased 30-day mortality (Denver: 11.3% vs 41.5% [P < .01]; DOFA: 12.6% vs 46.2% [P < .01]; MODS: 12.5% vs 35.9% [P < .01]), as was MOF by any criteria (10.8% vs 35.7 %; P < .01). Patients with MOF were more likely to have a higher body mass index (55.9±26.6 vs 49.0±15.0; P = .011) and to have had a preoperative stroke (17.9% vs 6.0%; P = .016). Patients with MOF were less likely to have undergone endovascular repair (30.4% vs 62.1%; P < .001). Endovascular repair was protective against MOF (any criteria) on multivariate analysis (odds ratio, 0.23; 95% confidence interval, 0.08-0.64; P = .019) after adjusting for age, gender, and presenting systolic blood pressure.

CONCLUSIONS

MOF occurred in only 9% to 14% of patients after rAAA repair, but was associated with a three-fold increase in mortality. Endovascular repair was associated with a reduced MOF incidence.

Selective Publication within Vascular Surgery: Characteristics of Discontinued and Unpublished Randomized Clinical Trials

BACKGROUND

Discontinued and unpublished randomized clinical trials (RCTs) are common resulting in biased publication and loss of potential knowledge. The magnitude of selective publication within vascular surgery remains unknown.

METHODS

RCT relevant to vascular surgery registered (01/01/2010-10/31/2019) on ClinicalTrials.gov were included. Trials ending normally with conclusion of participant treatment and examination were considered completed whereas discontinued trials stopped early. Publications were identified through automatically indexed PubMed citations on ClinicalTrials.gov or manually identified on PubMed or Google Scholar >30 months after the completion date, the date the final participant was examined, allowing time for publication.

RESULTS

Of 108 RCT (n = 37, 837), 22.2% (24/108) were discontinued, including 16.7% (4/24) stopped prior to and 83.3% (20/24) after starting enrollment. Only 28.4% of estimated enrollment was achieved for all discontinued RCT. Nineteen (79.2%) investigators provided a reason for discontinuation, which most commonly included poor enrollment (45.8%), inadequate supplies or funding (12.5%), and trial design concerns (8.3%). Of the 20 trials terminated following enrollment, 20.0% (4/20) were published in peer-reviewed journals and 80.0% (16/20) failed to reach publication. Of the 77.8% trials completed, 75.0% (63/84) were published and 25.0% (21/84) remain unpublished. In a multivariate regression of completed trials, industry funding was significantly associated with decreased likelihood of peer-reviewed publication (OR = 0.18, (95% CI 0.05-0.71), P = 0.01). Of the discontinued and completed trials remaining unpublished, 62.5% and 61.9% failed to report results on ClinicalTrials.gov, respectively, encompassing a total of 4,788 enrollees without publicly available results.

CONCLUSIONS

Nearly 25% of registered vascular RCT were discontinued. Of completed RCT, 25% remain unpublished with industry funding associated with decreased likelihood of publication. This study identifies opportunities to report all findings for completed and discontinued vascular surgery RCT, whether industry sponsored, or investigator initiated.

Time to treatment and mortality for clinical sepsis subtypes

BACKGROUND

Sepsis is common, deadly, and heterogenous. Prior analyses of patients with sepsis and septic shock in New York State showed a risk-adjusted association between more rapid antibiotic administration and bundled care completion, but not an intravenous fluid bolus, with reduced in-hospital mortality. However, it is unknown if clinically identifiable sepsis subtypes modify these associations.

METHODS

Secondary analysis of patients with sepsis and septic shock enrolled in the New York State Department of Health cohort from January 1, 2015 to December 31, 2016. Patients were classified as clinical sepsis subtypes (α, β, γ, δ-types) using the Sepsis ENdotyping in Emergency CAre (SENECA) approach. Exposure variables included time to 3-h sepsis bundle completion, antibiotic administration, and intravenous fluid bolus completion. Then logistic regression models evaluated the interaction between exposures, clinical sepsis subtypes, and in-hospital mortality.

RESULTS

55,169 hospitalizations from 155 hospitals were included (34% α, 30% β, 19% γ, 17% δ). The α-subtype had the lowest (N = 1,905, 10%) and δ-subtype had the highest (N = 3,776, 41%) in-hospital mortality. Each hour to completion of the 3-h bundle (aOR, 1.04 [95%CI, 1.02-1.05]) and antibiotic initiation (aOR, 1.03 [95%CI, 1.02-1.04]) was associated with increased risk-adjusted in-hospital mortality. The association differed across subtypes (p-interactions < 0.05). For example, the outcome association for the time to completion of the 3-h bundle was greater in the δ-subtype (aOR, 1.07 [95%CI, 1.05-1.10]) compared to α-subtype (aOR, 1.02 [95%CI, 0.99-1.04]). Time to intravenous fluid bolus completion was not associated with risk-adjusted in-hospital mortality (aOR, 0.99 [95%CI, 0.97-1.01]) and did not differ among subtypes (p-interaction = 0.41).

CONCLUSION

Timely completion of a 3-h sepsis bundle and antibiotic initiation was associated with reduced risk-adjusted in-hospital mortality, an association modified by clinically identifiable sepsis subtype.

Assessing the Prevalence of Medical Optimization Therapy in Vascular Surgery Clinics

This cross-sectional study uses checklist data to assess optimal medical therapy prescribed for veterans with atherosclerotic cardiovascular disease.

Drainage of anorectal abscesses in the operating room is associated with a decreased risk of abscess recurrence and fistula formation

BACKGROUND

Timely incision and drainage (I&D) is first line management for anorectal abscesses. We aimed to define current practices in anorectal abscess management and identify factors associated with abscess recurrence and fistula formation.

METHODS

Index episodes of anorectal abscesses treated with I&D in 2014-2018 at a multi-hospital healthcare system were included. Association with one-year abscess recurrence or fistula formation was evaluated using Cox proportional hazard regression. Fistulae were captured only among patients without fistulae at the index operation.

RESULTS

A total of 458 patients met study criteria. One-year rate of abscess recurrence or fistula formation was 20.3%. When compared to bedside procedures, drainage in the operating room was associated with a reduced risk of either recurrence or fistula formation (aHR 0.20 [95%CI 0.114-0.367]).

CONCLUSIONS

Improved exposure and patient comfort in the operating room may allow more complete drainage contributing to decreased rates of abscess recurrence or fistula formation.

MetfOrmin BenefIts Lower Extremities with Intermittent Claudication (MOBILE IC): randomized clinical trial protocol

BACKGROUND

Peripheral artery disease (PAD) affects over 230 million people worldwide and is due to systemic atherosclerosis with etiology linked to chronic inflammation, hypertension, and smoking status. PAD is associated with walking impairment and mobility loss as well as a high prevalence of coronary and cerebrovascular disease. Intermittent claudication (IC) is the classic presenting symptom for PAD, although many patients are asymptomatic or have atypical presentations. Few effective medical therapies are available, while surgical and exercise therapies lack durability. Metformin, the most frequently prescribed oral medication for Type 2 diabetes, has salient anti-inflammatory and promitochondrial properties. We hypothesize that metformin will improve function, retard the progression of PAD, and improve systemic inflammation and mitochondrial function in non-diabetic patients with IC.

METHODS

200 non-diabetic Veterans with IC will be randomized 1:1 to 180-day treatment with metformin extended release (1000 mg/day) or placebo to evaluate the effect of metformin on functional status, PAD progression, cardiovascular disease events, and systemic inflammation. The primary outcome is 180-day maximum walking distance on the 6-min walk test (6MWT). Secondary outcomes include additional assessments of functional status (cardiopulmonary exercise testing, grip strength, Walking Impairment Questionnaires), health related quality of life (SF-36, VascuQoL), macro- and micro-vascular assessment of lower extremity blood flow (ankle brachial indices, pulse volume recording, EndoPAT), cardiovascular events (amputations, interventions, major adverse cardiac events, all-cause mortality), and measures of systemic inflammation. All outcomes will be assessed at baseline, 90 and 180 days of study drug exposure, and 180 days following cessation of study drug. We will evaluate the primary outcome with linear mixed-effects model analysis with covariate adjustment for baseline 6MWT, age, baseline ankle brachial indices, and smoking status following an intention to treat protocol.

DISCUSSION

MOBILE IC is uniquely suited to evaluate the use of metformin to improve both systematic inflammatory responses, cellular energetics, and functional outcomes in patients with PAD and IC.

TRIAL REGISTRATION

The prospective MOBILE IC trial was publicly registered (NCT05132439) November 24, 2021.

Adductor Canal Syndrome After Lesser Trochanter Avulsion Fracture in a 19 Year Old

A rare cause of limb ischemia in young patients, adductor canal syndrome, can be debilitating and result in functional impairment. Diagnosis and treatment may be delayed due to this vascular disease's rarity in young people and because the presenting symptoms can overlap with other more common causes of leg pain in young athletes. Here, authors discuss a young athletic patient with a history of year-long claudication. The patient's reported symptoms, exam findings, and imaging results were consistent with a diagnosis of adductor canal syndrome. This case proved uniquely challenging, given the extent of disease and illustrates potential approach considerations.

Characterization of immediate and early mortality after repair of ruptured abdominal aortic aneurysm

BACKGROUND

We sought to compare immediate and early mortality among patients undergoing ruptured abdominal aortic aneurysm (RAAA) repair. Evaluation of RAAA has focused on 30-day postoperative mortality. Other emergency conditions such as trauma have demonstrated a multimodal mortality distribution within the 30-day window, expanding the pathophysiologic understanding and allowing for intervention investigations with practice changing and lifesaving results. However, the temporal distribution and risk factors of postoperative morbidity and mortality in RAAA have yet to be investigated.

METHODS

We evaluated factors associated with RAAA postoperative mortality in immediate (<1 day) and early (1-30 days) postoperative periods in a landmarked retrospective cohort study using data from the Vascular Quality Initiative (2010-2020).

RESULTS

We identified 5157 RAAA repairs (mean age, 72 ± 10 years; 77% male; 88% White; 61% endovascular). The mortality rate in the immediate period was 10.2% (528/5157) and the early mortality rate was 22.1% (918/4163). In multivariable regression analyses, signs of hemorrhagic shock (ie, hemoglobin <7 g/dL: adjusted odds ratio [aOR], 1.87 [95% confidence interval [CI], 1.14-3.06]; any preoperative systolic blood pressure <70 mm Hg: aOR, 1.40 [95% CI, 1.04-1.89]; and estimated blood loss >40%: aOR, 3.65 [95% CI, 2.29-5.83]) were associated with an increased risk of immediate mortality. Comorbid conditions (heart failure: aOR, 1.38 [95% CI, 1.00-1.92]; pulmonary disease: aOR, 1.29 [95% CI, 1.05-1.58]; elevated creatinine: aOR 1.26 [95% CI, 1.31-1.41]) were associated with increased risk of early mortality.

CONCLUSIONS

Immediate deaths were associated predominantly with shock from massive hemorrhage, whereas early deaths were associated with comorbid conditions predisposing patients to multisystem organ failure despite successful repair. These temporal distinctions should guide future mechanistic and intervention evaluations to improve RAAA mortality.

Epidemiology of age-, sex-, and race-specific hospitalizations for abdominal aortic aneurysms highlights gaps in current screening recommendations

BACKGROUND

The detection and elective repair of abdominal aortic aneurysms (AAA) guided by known risk-factor specific screening decrease AAA-related mortality. However, minimal epidemiologic data exist for AAA in female persons and racial minority groups. We established the contemporary risk of US AAA hospitalization across age, sex, and race.

METHODS

National Inpatient Sample and US Census (2012-2018) data were used to quantify age-, sex-, and race-specific incidences and adjusted odds ratios (aOR) of AAA hospitalizations (≥18 years), associated risk factors, and in-hospital mortality. Interaction terms evaluated subgroups.

RESULTS

Among 1,728,374,183 US residents during the study period (51.3% female; 78.4% White, 12.7% Black, 5.7% Asian), 211,501,703 were hospitalized (aged 57.56 ± 0.04 years; 58.4% female; 64.9% White, 14.3% Black, 2.5% Asian) of which 291,850 were for AAA (aged 73.17 ± 0.04 years; 22.6% female; 81.8% White, 5.6% Black, 1.6% Asian). An estimated 15.2 (95% CI, 15.1-15.3) and 1.7 (95% CI, 1.7-1.7) hospitalizations per 100,000 residents were for intact AAA (iAAA) and ruptured AAA (rAAA) AAA, respectively. In addition, 16.2% of iAAA (83.8% male; 79.1% White) and 18.4% of rAAA (86.4% male; 75.0% White) hospitalizations occurred in patients less than 65 years of age. For iAAA, female sex (aOR, 0.27; 95% CI, 0.27-0.28) compared with male sex and both Black (0.47; 95% CI, 0.45-0.49) and Asian (0.86; 95% CI, 0.83-0.93) persons compared with White persons had a reduced aOR for hospitalization. For rAAA, the reduced aOR persisted for female sex (0.33; 95% CI, 0.32-0.36) and for Black persons (0.52; 95% CI, 0.46-0.58). Although female sex demonstrated an overall decreased odds of AAA hospitalization, female persons who were older, Black, or had peripheral vascular disease (Pinteractions < .001) had a relative increase in AAA hospitalization aOR. Female sex (aOR, 1.54; 95% CI, 1.38-1.70), but not Black or Asian race, was associated with increased mortality which was more pronounced for iAAA (1.93; 95% CI, 1.66-2.25) than rAAA (1.29; 95% CI, 1.13-1.48]; Pinteraction < .001).

CONCLUSIONS

We confirmed a substantially decreased adjusted risk of AAA hospitalization for females and racial minority groups; however, aging and comorbid peripheral vascular disease decreased these differences. The disparate risk of AAA hospitalization by sex and race highlights the importance of inclusivity in future AAA studies.

Young patients without prior vascular disease are at increased risk of limb loss and reintervention after acute limb ischemia

BACKGROUND

The objective of the present study was to categorize the presentation and treatment of acute limb ischemia (ALI) in young patients and compare the adverse outcomes after revascularization compared with that of older patients.

METHODS

All the patients who had presented to a multi-institution healthcare system with ALI from 2016 to 2020 were identified. The presenting features, operative details, and outcomes were included in the present analysis. Patients with existing peripheral arterial disease (acute on chronic) were analyzed separately from those without (de novo thrombosis or embolus). Within these groups, younger patients (age, ≤50 years) were compared with older patients (age, >50 years). The 3-month major adverse limb event-free survival was the primary outcome.

RESULTS

A total of 232 patients (age, 60 ± 16 years; 44% female sex, 87% white race) were included in the analysis. Of the 232 patients, 119 were in the acute on chronic cohort and 113 were in the de novo thrombosis/embolism cohort. Age did not affect the overall outcomes (P = .45) or the outcomes for the acute on chronic group (P = .17). However, in the de novo thrombosis/embolism cohort, patients aged ≤50 years had worse major adverse limb event-free survival compared with patients aged >50 years (hazard ratio, 2.47; 95% confidence interval, 1.08-5.68; P = .03) after adjustment for Rutherford class, interval from presentation to the operating room, and smoking status. In the de novo thrombosis/embolism group, the operative approach was similar across the age groups (endovascular, 12% vs 14%; open, 48% vs 41%; hybrid, 41% vs 45%; P = .78). In the younger patients, embolism was more likely from a proximal arterial source (71%). In contrast, in the older patients, the source of embolism was more often a cardiac source (86%). The rates of hypercoagulable disease were equal across the age groups (10% vs 10%; P = .95). The In-hospital mortality was 3% overall (acute on chronic, 5%; de novo, 3%).

CONCLUSIONS

Despite advances in interventional options, for patients with ALI due to de novo thrombosis or embolus, younger age was associated with worse short-term limb-related outcomes.

Association between neighborhood deprivation and presenting with a ruptured abdominal aortic aneurysm before screening age

OBJECTIVE

Recent data indicate social determinants of health (SDOH) have a great impact on prevention and treatment outcomes across a broad variety of disease states, especially cardiovascular diseases. The area deprivation index (ADI) is a validated measure of neighborhood level disadvantage capturing key social determinate factors. Abdominal aortic aneurysm rupture (rAAA) is highly morbid, but also preventable through evidence-based screening. However, the association between rAAA and SDOH is poorly characterized. Our objective is to study the association of SDOH with rAAA and screening age.

METHODS

This retrospective study included patients who underwent operative repair of a rAAA at a multihospital healthcare system (2003-2019). Deprivation was measured by the ADI (scale 1-100), grouped into quintiles for simplicity, with higher quintiles indicating greater deprivation. Patients with the highest quintile ADI (89-100) were categorized as the most deprived. We investigated the association between neighborhood deprivation with the odds of (i) undergoing repair for rAAA before screening age 65 and (ii) undergoing endovascular aortic repair (EVAR) using logistic regression, sequentially modeling nonmodifiable then both nonmodifiable and modifiable confounding variables.

RESULTS

There were 632 patients who met the inclusion criteria (aged 74.2 ± 9.4 years; 174 women [27.6%]; 564 White [89.2%]; ADI 66.8 ± 22.3). Those from the most deprived neighborhoods (n = 118) were younger (71.7 ± 10.0 years vs 74.8 ± 9.2 years; P = .002), more likely to be female (36% vs 26%; P = .031), more likely to be Black (5.9% vs 0.4%; P = .007), and fewer underwent EVAR (28% vs 39.5%; P = .020) compared with those from other neighborhoods. On sequential modeling, residing in the most deprived neighborhoods was associated with undergoing rAAA repair before age 65 after adjusting for nonmodifiable factors (odds ratio [OR], 2.02; 95% confidence interval [CI], 1.39-2.95; P < .001), and nonmodifiable as well as modifiable factors (OR, 2.22; 95% CI, 1.56-3.16; P < .001). Those in the most deprived neighborhoods had a lower odds of undergoing EVAR compared with open repair after adjusting for nonmodifiable factors (OR, 0.64; 95% CI, 0.41-0.98; P = .042), and nonmodifiable as well as modifiable factors (OR, 0.61; 95% CI, 0.37-0.99; P = .047).

CONCLUSIONS

Among patients who underwent rAAA, residing in the most deprived neighborhoods was associated with greater adjusted odds of presenting under age 65 and undergoing an open repair. These neighborhoods represent tangible geographic targets that may benefit from a younger screening age, enhanced education, and access to care. These findings stress the importance of developing strategies for early prevention and diagnosis of cardiovascular diseases among patients with disadvantageous SDOH.

Prehospital plasma is associated with survival principally in patients transferred from the scene of injury: A secondary analysis of the PAMPer trial

BACKGROUND

We sought to characterize if prehospital transfer origin from the scene of injury (SCENE) or from a referral emergency department (REF) alters the survival benefit attributable to prehospital plasma resuscitation in patients at risk of hemorrhagic shock.

METHODS

We performed a secondary analysis of data from a recently completed prehospital plasma clinical trial. All of the enrolled patients from either the SCENE or REF groups were included. The demographics, injury characteristics, shock severity and resuscitation needs were compared. The primary outcome was a 30-day mortality. Kaplan-Meier analysis and Cox-hazard regression were used to characterize the independent survival benefits of prehospital plasma for transport origin groups.

RESULTS

Of the 501 enrolled patients, the REF group patients (n = 111) accounted for 22% with the remaining (n = 390) originating from the scene. The SCENE group patients had higher injury severity and were more likely intubated prehospital. The REF group patients had longer prehospital times and received greater prehospital crystalloid and blood products. Kaplan-Meier analysis revealed a significant 30-day survival benefit associated with prehospital plasma in the SCENE group (P < .01) with no difference found in the REF group patients (P = .36). The Cox-regression verified after controlling for relevant confounders that prehospital plasma was independently associated with a 30-day survival in the SCENE group patients (hazard ratio 0.59; 95% confidence interval 0.39-0.89; P = .01) with no significant relationship found in the REF group patients (hazard ratio 1.03, 95% confidence interval 0.4-3.0).

CONCLUSION

Important differences across the SCENE and REF cohorts exist that are essential to understand when planning prehospital studies. Prehospital plasma is associated with a survival benefit primarily in SCENE group patients. The results are exploratory but suggest transfer origin may be an important determinant of prehospital plasma benefit.

Association Between Time to Source Control in Sepsis and 90-Day Mortality

Importance

Rapid source control is recommended to improve patient outcomes in sepsis. Yet there are few data to guide how rapidly source control is required.

Objective

To determine the association between time to source control and patient outcomes in community-acquired sepsis.

Design, Setting, and Particpants

Multihospital integrated health care system cohort study of hospitalized adults (January 1, 2013, to December 31, 2017) with community-acquired sepsis as defined by Sepsis-3 who underwent source control procedures. Follow-up continued through January 1, 2019, and data analyses were completed March 17, 2022.

Exposures

Early (<6 hours) compared with late (6-36 hours) source control as well as each hour of source control delay (1-36 hours) from sepsis onset.

Main Outcomes and Measures

Multivariable models were clustered at the level of hospital with adjustment for patient factors, sepsis severity, resource availability, and the physiologic stress of procedures generating adjusted odds ratios (aOR) and 95% CI.

Results

Of 4962 patients with sepsis (mean [SD] age, 62 [16] years; 52% male; 85% White; mean [SD] Sequential Organ Failure Assessment score, 3.8 [2.5]), source control occurred at a median (IQR) of 15.4 hours (5.5-21.7) after sepsis onset, with 1315 patients (27%) undergoing source control within 6 hours. The crude 90-day mortality was similar for early and late source control (n = 177 [14%] vs n = 529 [15%]; P = .35). In multivariable models, early source control was associated with decreased risk-adjusted odds of 90-day mortality (aOR, 0.71; 95% CI, 0.63-0.80). This association was greater among gastrointestinal and abdominal (aOR, 0.56; 95% CI, 0.43-0.80) and soft tissue interventions (aOR, 0.72; 95% CI, 0.55-0.95) compared with orthopedic and cranial interventions (aOR, 1.33; 95% CI, 0.96-1.83; P < .001 for interaction).

Conclusions and Relevance

Source control within 6 hours of community-acquired sepsis onset was associated with a reduced risk-adjusted odds of 90-day mortality. Prioritizing the rapid identification of septic foci and initiation of source control interventions can reduce the number of avoidable deaths among patients with sepsis.

A single institutional experience with suction thrombectomy in acute mesenteric ischemia

Acute mesenteric ischemia (AMI) is typically treated by open surgery or hybrid techniques. Catheter-based aspiration thrombectomy represents another minimally invasive alternative with a potential additional safety benefit of minimizing the bleeding risk associated with thrombolytics. In this institutional case series, we present five clinical cases of aspiration thrombectomy for high-risk AMI using the Penumbra aspiration system. All patients underwent technically successful endovascular thrombectomy as demonstrated by intraoperative angiography results. However, bowel necrosis and sepsis adversely affected postoperative outcomes. Lack of intraoperative bowel assessment is a limitation of endovascular methods, highlighting the importance of patient selection.

Consensus Current Procedural Terminology Code Definition of Source Control for Sepsis

INTRODUCTION

Unlike antibiotic and perfusion support, guidelines for sepsis source control lack high-quality evidence and are ungraded. Internally valid administrative data methods are needed to identify cases representing source control procedures to evaluate outcomes.

METHODS

Over five modified Delphi rounds, two independent reviewers identified Current Procedural Terminology (CPT) codes pertinent to source control. In each round, codes with perfect agreement were retained or excluded, whereas disagreements were reviewed by the panelists. Manual review of 400 patient records meeting Sepsis-3 criteria (2010-2017) clinically adjudicated which encounters included source control procedures (gold standard). The performance of consensus codes was compared with the gold standard to assess sensitivity, specificity, predictive values, and likelihood ratios.

RESULTS

Of 5752 CPT codes, 609 consensus codes represented source control procedures. Of 400 hospitalizations for sepsis, 39 (9.8%; 95% confidence interval [CI] 7.0%-13.1%) underwent gold standard source control procedures and 29 (7.3%; 95% CI 4.9-10.3%) consensus code-defined source control procedures. Thirty consensus codes were identified (20.0% gastrointestinal/intraabdominal, 10.0% genitourinary, 13.3% hepatopancreatobiliary, 23.3% orthopedic/cranial, 23.3% soft tissue, and 10.0% intrathoracic), which had 61.5% (95% CI 44.6%-76.6%) sensitivity, 98.6% (95% CI 96.8%-99.6%) specificity, 83.2% (95% CI 66.6%-92.4%) positive, and 95.9% (95% CI 93.9%-97.2%) negative predictive values. With pretest probability at sample prevalence, an identified consensus code had a posttest probability of 83.0% (95% CI 66.0%-92.0%), whereas consensus code absence had a probability of 4.0% (95% CI 3.0-6.0) for undergoing a source control procedure.

CONCLUSIONS

Using modified Delphi methodology, we created and validated CPT codes identifying source control procedures, providing a framework for evaluation of the surgical care of patients with sepsis.

Any Postoperative Surveillance Improves Survival after Endovascular Repair of Ruptured Abdominal Aortic Aneurysms

BACKGROUND

Endovascular aortic repair (EVAR) has advanced the care of patients with ruptured abdominal aortic aneurysms (rAAA) with improved early postoperative morbidity and mortality. However, this comes at the cost of a rigorous postoperative surveillance schedule to monitor for further aneurysmal degeneration. Adherence to surveillance recommendations is known to be poor in the elective setting, but has yet to be studied in the ruptured population. The aim of this study is to investigate predictors of incomplete surveillance after EVAR for rAAA (rEVAR) and examine how adherence impacts outcomes.

METHODS

This was a retrospective case control study of patients undergoing rEVAR at a multiple hospital single healthcare center (2003-2020). Patients were excluded if they underwent open conversion during their index hospitalization or died within 60 days of surgery. Follow-up was broadly categorized as complete surveillance (60-day postoperative visit and annually thereafter) or incomplete surveillance, comprising both patients with less than recommended surveillance (minimal surveillance) and completely lost to follow-up (LTF). Any follow-up was defined as patients with complete or minimal surveillance. We investigated predictors of complete versus incomplete surveillance by multivariate logistic regression. Secondary outcomes included overall survival and cumulative incidence of reintervention controlling for the competing risk of mortality, generating hazard ratios (HR) and subdistribution hazard ratios (SHR).

RESULTS

One-hundred and sixty patients (mean age 74 ± 10.1 years, 81.2% male) out of 673 total rAAA met study inclusion criteria. Complete surveillance was seen in 41.3% of our cohort, with the remainder with minimal surveillance (29.4%) or LTF (29.4%). Incomplete surveillance was associated with male sex (odds ratio [OR] 2.56; 95% CI 1.02-6.43), lack of a primary care provider (PCP; OR 0.20; 95% CI 0.04-0.99), and longer driving distance from home to treating hospital (OR 2.37; 95% CI 1.08-5.20). Survival was not different between complete and incomplete surveillance groups, however any follow-up conferred improved survival over LTF (HR 0.57; 95% CI 0.331-0.997; P = 0.049). Reintervention was associated with incomplete surveillance (SHR 0.29; 95% CI 0.11-0.75), and discharge to a facility (SHR 0.25; 95% CI 0.067-0.94).

CONCLUSIONS

Incomplete surveillance was observed in over 50% of patients who underwent rEVAR and was associated with male sex, lack of PCP, and longer driving distance. Any follow-up conferred a survival benefit, yet incomplete surveillance was associated with a lower risk of reintervention. Targeted strategies to prevent LTF, and less stringent, personalized follow-up plans that may confer similar survival benefit with better patient adherence should be investigated.

Comparing Veterans Affairs and Private Sector Perioperative Outcomes After Noncardiac Surgery

Importance

Recent legislation facilitates veterans' ability to receive non-Veterans Affairs (VA) surgical care. However, contemporary data comparing the quality and safety of VA and non-VA surgical care are lacking.

Objective

To compare perioperative outcomes among veterans treated in VA hospitals with patients treated in private-sector hospitals.

Design, Setting, and Participants

This cohort study took place across 8 noncardiac specialties in the Veterans Affairs Surgical Quality Improvement Program (VASQIP) and American College of Surgeons National Surgical Quality Improvement Program (NSQIP) from January 1, 2015, through December 31, 2018. Multivariable log-binomial modeling was used to evaluate the association between VA vs private sector care settings and 30-day mortality. Unmeasured confounding was quantified using the E-value. Patients 18 years and older undergoing a noncardiac procedures were included.

Exposures

Surgical care in either a VA or private sector setting.

Main Outcomes and Measures

Primary outcome was 30-day postoperative mortality. Secondary outcome was failure to rescue, defined as a postoperative death after a complication.

Results

Of 3 910 752 operations (3 174 274 from NSQIP and 736 477 from VASQIP), 1 498 984 (92.1%) participants in NSQIP were male vs 678 382 (47.2%) in VASQIP (mean difference, -0.449 [95% CI, -0.450 to -0.448]; P < .001), and 441 894 (60.0%) participants in VASQIP were frail or very frail vs 676 525 (21.3%) in NSQIP (mean difference, -0.387 [95% CI, -0.388 to -0.386]; P < .001). Overall, rates of 30-day mortality, complications, and failure to rescue were 0.8%, 9.5%, and 4.7%, respectively, in NSQIP (n = 3 174 274 operations) and 1.1%, 17.1%, and 6.7%, respectively in VASQIP (736 477) (differences in proportions, -0.003 [95% CI, -0.003 to -0.002]; -0.076 [95% CI, -0.077 to -0.075]; 0.020 [95% CI, 0.018-0.021], respectively; P < .001). Compared with private sector care, VA surgical care was associated with a lower risk of perioperative death (adjusted relative risk, 0.59 [95% CI, 0.47-0.75]; P < .001). This finding was robust in multiple sensitivity analyses performed, including among patients who were frail and nonfrail, with or without complications, and undergoing low and high physiologic stress procedures. These findings were also consistent when year was included as a covariate and in nonparsimonious modeling for patient-level factors. Compared with private sector care, VA surgical care was also associated with a lower risk of failure to rescue (adjusted relative risk, 0.55 [95% CI, 0.44-0.68]). An unmeasured confounder (present disproportionately in NSQIP data) would require a relative risk of 2.78 [95% CI, 2.04-3.68] to obviate the main finding.

Conclusions and Relevance

VA surgical care is associated with lower perioperative mortality and decreased failure to rescue despite veterans having higher-risk characteristics. Given the unique needs and composition of the veteran population, health policy decisions and budgetary appropriations should reflect these important differences.

Using the Unified Medical Language System to Expand the Operative Stress Score - First Use Case

BACKGROUND

The Unified Medical Language System (UMLS) maps relationships between and within >100 biomedical vocabularies, including Current Procedural Terminology (CPT) codes, creating a powerful knowledge resource which can accelerate clinical research.

METHODS

We used synonymy and concepts relating hierarchical structure of CPT codes within the UMLS, (1) guiding surgical experts in expanding the Operative Stress Score (OSS) from 565 originally rated CPT codes to additional, 1,853 related procedures; (2) establishing validity of the association between the added OSS ratings and 30-day outcomes in VASQIP (2015-2018).

RESULTS

The UMLS Metathesaurus and Semantic Network was converted into an interactive graph database (https://github.com/dbmi-pitt/UMLS-Graph) delineating ontology relatedness. From this UMLS-graph, the CPT hierarchy was queried obtaining all paths from each code to the hierarchical apex. Of 1,853 added ratings, 43% and 76% were siblings and cousins of original OSS CPT codes. Of 857,577 VASQIP cases (mean age, 64±11years; 91% male; 75% white), 786,122 (92%) and 71,455 (8%) were rated in the original and added OSS. Compared to original, added OSS cases included more females (14% versus 9%) and frail patients (25% versus 19%) undergoing high stress procedures (11% versus 8%; all P <.001). Postoperative mortality consistently increased with OSS. Very low stress procedures had <0.5% (original, 0.4% [95%CI, 0.4%-0.5%] versus added, 0.9% [95%CI, 0.6%-1.2%]) and very high 3.8% (original, 3.5% [95%CI, 3.0%-4.0%] versus added, 5.8% [95%CI, 4.6-7.3%]) mortality rates.

CONCLUSIONS

The synonymy and concepts relating biomedical data within the UMLS can be abstracted and efficiently used to expand the utility of existing clinical research tools.

Healthcare providers' perceived support from their organization is associated with lower burnout and anxiety amid the COVID-19 pandemic

BACKGROUND

Professional burnout represents a significant threat to the American healthcare system. Organizational and individual factors may increase healthcare providers' susceptibility or resistance to burnout. We hypothesized that during the COVID-19 pandemic, 1) higher levels of perceived organizational support (POS) are associated with lower risk for burnout and anxiety, and 2) anxiety mediates the association between POS and burnout.

METHODS

In this longitudinal prospective study, we surveyed healthcare providers employed full-time at a large, multihospital healthcare system monthly over 6 months (April to November 2020). Participants were randomized using a 1:1 allocation stratified by provider type, gender, and academic hospital status to receive one of two versions of the survey instrument formulated with different ordering of the measures to minimize response bias due to context effects. The exposure of interest was POS measured using the validated 8-item Survey of POS (SPOS) scale. Primary outcomes of interest were anxiety and risk for burnout as measured by the validated 10-item Burnout scale from the Professional Quality (Pro-QOL) instrument and 4-item Emotional Distress-Anxiety short form of the Patient Reported Outcome Measurement Information System (PROMIS) scale, respectively. Linear mixed models evaluated the associations between POS and both burnout and anxiety. A mediation analysis evaluated whether anxiety mediated the POS-burnout association.

RESULTS

Of the 538 participants recruited, 402 (75%) were included in the primary analysis. 55% of participants were physicians, 73% 25-44 years of age, 73% female, 83% White, and 44% had ≥1 dependent. Higher POS was significantly associated with a lower risk for burnout (-0.23; 95% CI -0.26, -0.21; p<0.001) and lower degree of anxiety (-0.07; 95% CI -0.09, -0.06; p = 0.010). Anxiety mediated the associated between POS and burnout (direct effect -0.17; 95% CI -0.21, -0.13; p<0.001; total effect -0.23; 95% CI -0.28, -0.19; p<0.001).

CONCLUSION

During a health crisis, increasing the organizational support perceived by healthcare employees may reduce the risk for burnout through a reduction in anxiety. Improving the relationship between healthcare organizations and the individuals they employ may reduce detrimental effects of psychological distress among healthcare providers and ultimately improve patient care.

Early Postoperative Mortality Among US Veterans With a Robust Physiologic Reserve Undergoing Open or Endovascular Abdominal Aortic Aneurysm Repair

This cohort study uses data from the Veterans Affairs Surgical Quality Improvement Program database to examine the risk of early postoperative mortality among US veterans with a robust physiologic reserve undergoing open or endovascular abdominal aortic aneurysm repair.

Transanal excision with adjuvant therapy for pT1N0 rectal tumors with high-risk features offers equivalent survival to radical resection: A National Cancer Database analysis

BACKGROUND

Current guidelines favor transabdominal radical resection (RR) over transanal local excision (TAX) followed by adjuvant therapy (TAXa) for pT1N0 rectal tumors with high-risk features. Comparison of oncologic outcomes between these approaches is limited, although the former is associated with increased postoperative morbidity. We hypothesize that such treatment strategies result in equivalent long-term survival.

METHODS

A retrospective cohort study was conducted using the National Cancer Database (2010-2016) to identify patients with pT1N0 rectal adenocarcinoma with high-risk features who underwent TAX or RR for curative intent. The primary outcome was 5-year overall survival (OS), evaluated with log-rank and Cox-proportional hazards testing.

RESULTS

A total of 1159 patients (age 67.4 ± 12.9 years; 56.6% male; 83.3% White) met study criteria, of which 1009 (87.1%) underwent RR and 150 (12.9%) underwent TAXa. Patients undergoing TAXa had shorter lengths of stay (RR = 6.5 days, TAXa = 2.7 days, p < 0.001). The 5-year OS was equivalent between groups. TAX without adjuvant therapy was associated with an increased risk of mortality (hazard ratio 1.81, 95% confidence interval 1.17-2.78, p = 0.01).

CONCLUSIONS

This is the largest study to demonstrate equivalent 5-year OS between TAXa and RR for T1N0 rectal cancer with high-risk features. These findings may guide the development of prospective, randomized trials and influence changes in practice recommendations for early-stage rectal cancer.

Association of Smoking With Postprocedural Complications Following Open and Endovascular Interventions for Intermittent Claudication

Importance

Smoking is a key modifiable risk factor in the development and progression of peripheral artery disease, which often manifests as intermittent claudication (IC). Smoking cessation is a first-line therapy for IC, yet a minority of patients quit smoking prior to elective revascularization.

Objective

To assess if preprocedural smoking is associated with an increased risk of early postprocedural complications following elective open and endovascular revascularization.

Design, Setting, and Participants

This retrospective cohort study used nearest-neighbor (1:1) propensity score matching of 2011 to 2019 data from the Veterans Affairs Surgical Quality Improvement Program, including all cases with a primary diagnosis of IC and excluding emergent cases, primary procedures that were not lower extremity revascularization, and patients with chronic limb-threatening ischemia within 30 days of the intervention. All data were abstracted June 18, 2020, and analyzed from July 26, 2020, to June 30, 2021.

Exposures

Preprocedural cigarette smoking.

Main Outcomes and Measures

Any and organ system-specific (ie, wound, respiratory, thrombosis, kidney, cardiac, sepsis, and neurological) 30-day complications and mortality, overall and in prespecified subgroups.

Results

Of 14 350 included cases of revascularization, 14 090 patients (98.2%) were male, and the mean (SD) age was 65.7 (7.0) years. A total of 7820 patients (54.5%) were smoking within the preprocedural year. There were a total of 4417 endovascular revascularizations (30.8%), 4319 hybrid revascularizations (30.1%), and 5614 open revascularizations (39.1%). A total of 1594 patients (11.1%) had complications, and 57 (0.4%) died. Among 7710 propensity score-matched cases (including 3855 smokers and 3855 nonsmokers), 484 smokers (12.6%) and 34 nonsmokers (8.9%) experienced complications, an absolute risk difference (ARD) of 3.68% (95% CI, 2.31-5.06; P < .001). Compared with nonsmokers, any complication was higher for smokers following endovascular revascularization (26 [4.3%] vs 52 [2.1%]; ARD, 2.19%; 95% CI, 0.77-3.60; P = .003), hybrid revascularization (204 [17.3%] vs 163 [14.1%]; ARD, 3.18%; 95% CI, 0.23-6.13; P = .04), and open revascularization (228 [15.4%] vs 153 [10.3%]; ARD, 5.18%; 95% CI, 2.78-7.58; P < .001). Compared with nonsmokers, respiratory complications were higher for smokers following endovascular revascularization (20 [1.7%] vs 6 [0.5%]; ARD, 1.17%; 95% CI, 0.35-2.00; P = .009), hybrid revascularization (33 [2.8%] vs 10 [0.9%]; ARD, 1.93%; 95% CI, 0.85-3.02; P = .001), and open revascularization (32 [2.2%] vs 19 [1.3%]; ARD, 0.89%; 95% CI, 0-1.80; P = .06). Wound complications and graft failure were higher for smokers compared with nonsmokers following open interventions (wound complications: 146 [9.9%] vs 87 [5.8%]; ARD, 4.05%; 95% CI, 2.12-5.99; P < .001; graft failure: 33 [2.2%] vs 11 [0.7%]; ARD, 1.50%; 95% CI, 0.63-2.37; P = .001). In a sensitivity analysis, compared with active smokers (n = 5173; smoking within 2 weeks before the procedure), the risk of any complication was decreased by 65% for never smokers (n = 1197; adjusted odds ratio, 0.45; 95% CI, 0.34-0.59) and 29% for former smokers (n = 4755; cessation more than 1 year before the procedure; adjusted odds ratio, 0.71; 95% CI, 0.61-0.83; P = .001 for interaction).

Conclusions and Relevance

In this cohort study, more than half of patients with IC were smoking prior to elective revascularization, and complication risks were higher across all modalities of revascularization. These findings stress the importance of smoking cessation to optimize revascularization outcomes.

The Correlation Between Case Total Work Relative Value Unit, Operative Stress, and Patient Frailty: Retrospective Cohort Study

OBJECTIVE

Assess the relationships between case total work relative value units (wRVU), patient frailty, and the physiologic stress of surgical interventions.

SUMMARY OF BACKGROUND DATA

Surgeon reimbursement is frequently apportioned by wRVU. These subjective, procedure-specific valuations generated by physician survey estimate the intensity and time for typical patient care services. We hypothesized wRVU would not adequately account for patient-specific factors, such as frailty, that modify the required physician work, regardless of procedural complexity.

METHODS

Using National and Veterans Affairs Surgical Quality Improvement Programs (2015-2018), we evaluated the correlation between case total wRVU, patient frailty (risk analysis index) and physiologic surgical stress (operative stress score).

RESULTS

Of 4,111,371 (86%) cases, the correlation between total wRVU and operative stress was moderate [ρs = 0.587 (95% confidence interval, 0.586-0.587)], but negligible with frailty ρ = 0.177 (95% confidence interval, 0.176-0.178)]. Very high operative stress procedures [n = 34,047 (1%)] generated a mean total wRVU of 55.1 (standard deviation, 12.9), comprising 7%, 2%, and 1% of thoracic, vascular, and general surgical cases, respectively. Very frail patients [n = 152,535 (4%)] accounted for 9% of thoracic, 9% of vascular, 4% of general, 5% of urologic, and 4% of neurologic surgical cases, generating 21.0 (standard deviation, 12.4) mean total wRVU. Some nonfrail patients undergoing low operative stress procedures [n = 60,128 (2%)] nonetheless generated the highest quintile wRVU; these comprised >15% of plastic, gynecologic, and urologic surgical cases.

CONCLUSIONS

Surgeon reimbursement correlates with operative stress but not patient frailty. The total wRVU does not adequately reflect patient-specific factors that increase the physician workload required to render optimal care to complex patients.

Association Between Black Race, Clinical Severity, and Management of Acute Pulmonary Embolism: A Retrospective Cohort Study

Background

Existing evidence indicates Black patients have higher incidence of pulmonary embolism (PE) and PE‐related mortality compared with other races/ethnicities, yet disparities in presenting severity and treatment remain incompletely understood.

Methods and Results

We retrospectively queried a multihospital healthcare system for all hospitalizations for acute PE (2012–2019). Of 10 329 hospitalizations, 8743 met inclusion criteria. Black patients (14.3%) were significantly younger (54.6±17.8 versus 63.1±16.6 years; P<0.001) and more female (56.1% versus 51.6%; P=0.003) compared with White patients. Using ordinal regression, Black race was significantly associated with higher PE severity after matching 1:3 on age and sex (1210:3264; odds ratio [OR], 1.08; 95% CI, 1.03–1.14), adjusting for clinical (OR, 1.13; 95% CI, 1.01–1.27), and socioeconomic (OR, 1.05; 95% CI, 1.05–1.35) characteristics. Among intermediate and high‐severity PE, Black race was associated with a decreased risk of intervention controlling for the competing risk of mortality and censoring on hospital discharge. This effect was modified by PE severity (P value <0.001), with a lower and higher risk of intervention for intermediate and high‐severity PE, respectively. Race was not associated with in‐hospital mortality (OR, 0.84; 95% CI, 0.69–1.02).

Conclusions

Black patients hospitalized with PE are younger with a higher severity of disease compared with White patients. Although Black patients are less likely to receive an intervention overall, this differed depending on PE severity with higher risk of intervention only for life‐threatening PE. This suggests nuanced racial disparities in management of PE and highlights the complexities of healthcare inequalities.

Early Prehospital Tranexamic Acid Following Injury Is Associated With a 30-day Survival Benefit: A Secondary Analysis of a Randomized Clinical Trial

OBJECTIVE

We sought to characterize the timing of administration of prehospital tranexamic acid (TXA) and associated outcome benefits.

BACKGROUND

TXA has been shown to be safe in the prehospital setting post-injury.

METHODS

We performed a secondary analysis of a recent prehospital randomized TXA clinical trial in injured patients. Those who received prehospital TXA within 1 hour (EARLY) from time of injury were compared to those who received prehospital TXA beyond 1 hour (DELAYED). We included patients with a shock index of >0.9. Primary outcome was 30-day mortality. Kaplan-Meier and Cox Hazard regression were utilized to characterize mortality relationships.

RESULTS

EARLY and DELAYED patients had similar demographics, injury characteristics, and shock severity but DELAYED patients had greater prehospital resuscitation requirements and longer prehospital times. Stratified Kaplan-Meier analysis demonstrated significant separation for EARLY patients (N = 238, log-rank chi-square test, 4.99; P = 0.03) with no separation for DELAYED patients (N = 238, log-rank chi-square test, 0.04; P = 0.83). Stratified Cox Hazard regression verified, after controlling for confounders, that EARLY TXA was associated with a 65% lower independent hazard for 30-day mortality [hazard ratio (HR) 0.35, 95% confidence interval (CI) 0.19-0.65, P = 0.001] with no independent survival benefit found in DELAYED patients (HR 1.00, 95% CI 0.63-1.60, P = 0.999). EARLY TXA patients had lower incidence of multiple organ failure and 6-hour and 24-hour transfusion requirements compared to placebo.

CONCLUSIONS

Administration of prehospital TXA within 1 hour from injury in patients at risk of hemorrhage is associated with 30-day survival benefit, lower incidence of multiple organ failure, and lower transfusion requirements.

Age of thawed plasma does not affect clinical outcomes or biomarker expression in patients receiving prehospital thawed plasma: a PAMPer secondary analysis

Background

Prehospital plasma administration during air medical transport reduces the endotheliopathy of trauma, circulating pro-inflammatory cytokines, and 30-day mortality among traumatically injured patients at risk of hemorrhagic shock. No clinical data currently exists evaluating the age of thawed plasma and its association with clinical outcomes and biomarker expression post-injury.

Methods

We performed a secondary analysis from the prehospital plasma administration randomized controlled trial, PAMPer. We dichotomized the age of thawed plasma creating three groups: standard-care, YOUNG (day 0-1) plasma, and OLD (day 2-5) plasma. We generated HRs and 95% CIs for mortality. Among all patients randomized to plasma, we compared predicted biomarker values at hospital admission (T0) and 24 hours later (T24) controlling for key difference between groups with a multivariable linear regression. Analyses were repeated in a severely injured subgroup.

Results

Two hundred and seventy-one patients were randomized to standard-care and 230 to plasma (40% YOUNG, 60% OLD). There were no clinically or statistically significant differences in demographics, injury, admission vital signs, or laboratory values including thromboelastography between YOUNG and OLD. Compared with standard-care, YOUNG (HR 0.66 (95% CI 0.41 to 1.07), p=0.09) and OLD (HR 0.64 (95% CI 0.42 to 0.96), p=0.03) plasma demonstrated reduced 30-day mortality. Among those randomized to plasma, plasma age did not affect mortality (HR 1.04 (95% CI 0.60 to 1.82), p=0.90) and/or adjusted serum markers by plasma age at T0 or T24 (p>0.05). However, among the severely injured subgroup, OLD plasma was significantly associated with increased adjusted inflammatory and decreased adjusted endothelial biomarkers at T0.

Discussion

Age of thawed plasma does not result in clinical outcome or biomarker expression differences in the overall PAMPer study cohort. There were biomarker expression differences in those patients with severe injury. Definitive investigation is needed to determine if the age of thawed plasma is associated with biomarker expression and outcome differences following traumatic injury.

Level of evidence

II.

Complete Venous Ulceration Healing after Perforator Ablation Does Not Depend on Treatment Modality

BACKGROUND

Venous leg ulceration (VLU) represents the most advanced form of chronic venous insufficiency (CVI). Persistent VLU that fails to respond to noninvasive treatment requires a minimally invasive endovascular treatment, which may include chemical (ultrasound-guided foam sclerotherapy [UGFS]) and thermal ablation (endovenous laser therapy [EVLT] or radiofrequency ablation [RFA]) targeting incompetent veins. Current guidelines suggest ablation of incompetent perforating veins (IPVs) juxtaposed to active or healed VLU; however, the ideal treatment modality is unknown. We hypothesize that similar to incompetent superficial vein treatment options therapies, VLU healing will be equivalent across minimally invasive IPV treatment options.

METHODS

Using the Vascular Low Frequency Disease Consortium, adults with VLU across 11 medical centers were retrospectively reviewed (2013-2017). We included those who underwent IPV therapies. The primary outcome was complete ulcer healing over time compared with cumulative hazard curves, log-rank testing, and multivariable Cox proportional hazard regression. Secondary outcomes included number of subsequent procedures, which were compared using negative binomial regression.

RESULTS

Of the 832 adults with VLU, 158 (19%) were exclusively treated conservatively, and 232 (28%) underwent index treatment for IPV and constitute the full and final cohort. The mean age was 60 ± 14 years, 57% were men, and the mean ulcer area was 3.0 cm² (interquartile range, 1-6 cm²). Ninety-one (39%) were treated with EVLT, 127 (55%) RFA, and 14 (6%) UGFS. Patients treated with RFA were older (RFA 62 ± 14 years; EVLT 59 ± 14 years; UGFS 52 ± 9 years; P = 0.01), more likely to be men (RFA 68%, n = 86; EVLT 41%, n = 37; UGFS 64%, n = 9; P < 0.001), with a higher frequency of anticoagulation (RFA 36%, n = 46; EVLT 18%, n = 16; UGFS 14%, n = 2; P = 0.005). VLU did not significantly differ in size between groups (RFA 6.2 ± 8; EVLT 4.2 ± 5.4; UGFS 6.1 ± 8; P < 0.001). There were no differences in 1-year ulcer healing rates between groups (P = 0.18). The number of subsequent procedures did not differ by treatment modality (P = 0.47).

CONCLUSIONS

This multi-institutional retrospective study does not demonstrate any association of IPV treatment modality with differing rates of VLU healing or number of subsequent procedures.

Association Between Preoperative Metformin Exposure and Postoperative Outcomes in Adults With Type 2 Diabetes

Importance

Adults with comorbidity have less physiological reserve and an increased rate of postoperative mortality and readmission after the stress of a major surgical intervention.

Objective

To assess postoperative mortality and readmission among individuals with diabetes with or without preoperative prescriptions for metformin.

Design, Setting, and Participants

This cohort study obtained data from the electronic health record of a multicenter, single health care system in Pennsylvania. Included were adults with diabetes who underwent a major operation with hospital admission from January 1, 2010, to January 1, 2016, at 15 community and academic hospitals within the system. Individuals without a clinical indication for metformin therapy were excluded. Follow-up continued until December 18, 2018.

Exposures

Preoperative metformin exposure was defined as 1 or more prescriptions for metformin in the 180 days before the surgical procedure.

Main Outcomes and Measures

All-cause postoperative mortality, hospital readmission within 90 days of discharge, and preoperative inflammation measured by the neutrophil to leukocyte ratio were compared between those with and without preoperative prescriptions for metformin. The corresponding absolute risk reduction (ARR) and adjusted hazard ratio (HR) with 95% CI were calculated in a propensity score-matched cohort.

Results

Among the 10 088 individuals with diabetes who underwent a major surgical intervention, 5962 (59%) had preoperative metformin prescriptions. A total of 5460 patients were propensity score-matched, among whom the mean (SD) age was 67.7 (12.2) years, and 2866 (53%) were women. In the propensity score-matched cohort, preoperative metformin prescriptions were associated with a reduced hazard for 90-day mortality (adjusted HR, 0.72 [95% CI, 0.55-0.95]; ARR, 1.28% [95% CI, 0.26-2.31]) and hazard of readmission, with mortality as a competing risk at both 30 days (ARR, 2.09% [95% CI, 0.35-3.82]; sub-HR, 0.84 [95% CI, 0.72-0.98]) and 90 days (ARR, 2.78% [95% CI, 0.62-4.95]; sub-HR, 0.86 [95% CI, 0.77-0.97]). Preoperative inflammation was reduced in those with metformin prescriptions compared with those without (mean neutrophil to leukocyte ratio, 4.5 [95% CI, 4.3-4.6] vs 5.0 [95% CI, 4.8-5.3]; P < .001). E-value analysis suggested robustness to unmeasured confounding.

Conclusions and Relevance

This study found an association between metformin prescriptions provided to individuals with type 2 diabetes before a major surgical procedure and reduced risk-adjusted mortality and readmission after the operation. This association warrants further investigation.