Clinical Outcomes and Resource Utilization in Patients with Peripheral Arterial Disease Hospitalized for Acute Coronary Syndrome

Previous studies have shown an association between acute limb ischemia and higher mortality in patients with Acute Myocardial Infarction. Although Peripheral Artery Disease is a well-known risk factor for development of macrovascular pathology, the effect of its severity is not well investigated in patients hospitalized for Acute Coronary Syndrome (ACS). Using a national cohort of patients with various degrees of Peripheral Arterial Disease, we investigated in-hospital outcomes in patients who were admitted for ACS. Using the 2016-2020 Nationwide Readmissions Database, we queried all patients who were hospitalized for ACS (Unstable Angina, Non ST-Elevation Myocardial Infarction, and ST-Elevation Myocardial Infarction). Patients were further divided into three groups, either No Peripheral Arterial Disease (Non-PAD), Peripheral Arterial Disease (PAD) or Critical Limb Ischemia (CLI). Multivariable models were designed to adjust for patient and hospital factors and examine the association between ACS and PAD severity. Of an approximately 3,834,181 hospitalizations for ACS, 6.4% had PAD, 0.2% had CLI and all other were Non-PAD. Following risk adjustment, in hospital mortality was higher by 24% in PAD (AOR 1.24, 95%CI 1.21-1.28) and 86% in CLI (AOR 1.86, 95%CI 1.62-2.09) compared to Non-PAD. Furthermore, PAD and CLI were linked to 1.23-fold (95%CI 1.20-1.26) and 1.67-fold (95%CI 1.45-1.86) greater odds of cardiogenic shock compared to Non-PAD. Additionally, PAD and CLI were linked with higher odds of mechanical circulatory support usage, cardiac arrest and acute kidney injury compared to Non-PAD. Lastly, duration of hospital stay, hospitalization costs and odds of non-home discharge and 30-day readmissions were greater in patients with PAD and CLI compared to Non-PAD. PAD severity was associated with worse clinical outcomes in patients with ACS, including in hospital mortality and resource utilization.

Care fragmentation is associated with increased mortality after ileostomy creation

BACKGROUND

Ileostomy is the mainstay treatment option for various gastrointestinal conditions. Given the increased risk of post-discharge complications and high readmission rates that can be further aggravated by receiving care at different facilities (care fragmentation), further examination is necessary. We thus used a national cohort to explore the associations of care fragmentation among ileostomy patients experiencing adverse outcomes and increased hospitalization expenditures.

METHODS

All adult hospitalizations for ileostomy were tabulated from the 2016 to 2020 Nationwide Readmissions Database. Those readmitted within 90 days after discharge were included for analysis. Patients treated at a different facility than the original location where the index ileostomy was performed were categorized into the care-fragmented cohort. Multivariable regressions were developed to characterize the association of the care-fragmented cohort with postoperative outcomes, readmissions, and expenditures.

RESULTS

Of 52,254 patients with ileostomy creation hospitalizations with 90-day nonelective readmission, 9,045 (17.3%) experienced care fragmentation. Following risk adjustment, those experiencing care fragmentation faced increased odds of mortality (adjusted odds ratio 1.81, 95% confidence interval 1.54-2.12), cardiac (adjusted odds ratio 1.63, 95% confidence interval 1.42-1.85), respiratory (adjusted odds ratio 1.71, 95% confidence interval 1.53-1.91), infectious (adjusted odds ratio 1.33, 95% confidence interval 1.23-1.43), and thromboembolic (adjusted odds ratio 1.28, 95% confidence interval 1.13-1.45) complications. Furthermore, patients experiencing care fragmentation were more likely to have increased hospitalization costs ($1,700, 95% confidence interval 0.8-2.5).

CONCLUSION

Care fragmentation in ileostomy patients demonstrated an increased risk for mortality, postoperative complications, and increased hospitalization expenses. To mitigate risks for adverse outcomes, future studies should evaluate the impacts of inter-hospital communication with the goal of improving care continuity and optimizing healthcare delivery for care-fragmented populations.

The vagus nerve in cardiovascular physiology and pathophysiology: From evolutionary insights to clinical medicine

The parasympathetic nervous system via the vagus nerve exerts profound influence over the heart. Together with the sympathetic nervous system, the parasympathetic nervous system is responsible for fine-tuned regulation of all aspects of cardiovascular function, including heart rate, rhythm, contractility, and blood pressure. In this review, we highlight vagal efferent and afferent innervation of the heart, with a focus on insights from comparative biology and advances in understanding the molecular and genetic diversity of vagal neurons, as well as interoception, parasympathetic dysfunction in heart disease, and the therapeutic potential of targeting the parasympathetic nervous system in cardiovascular disease.

Anatomical and functional organization of cardiac fibers in the porcine cervical vagus nerve allows spatially selective efferent neuromodulation

Cardiac disease progression reflects the dynamic interaction between adversely remodeled neurohumoral control systems and an abnormal cardiac substrate. Vagal nerve stimulation (VNS) is an attractive neuromodulatory option to dampen this dynamic interaction; however, it is limited by off-target effects. Spatially-selective VNS (sVNS) offers a promising solution to induce cardioprotection while mitigating off-target effects by specifically targeting pre-ganglionic parasympathetic efferent cardiac fibers. This approach also has the potential to enhance therapeutic outcomes by eliminating time-consuming titration required for optimal VNS. Recent studies have demonstrated the independent modulation of breathing rate, heart rate, and laryngeal contraction through sVNS. However, the spatial organization of afferent and efferent cardiac-related fibers within the vagus nerve remains unexplored. By using trial-and-error sVNS in vivo in combination with ex vivo micro-computed tomography fascicle tracing, we show the significant spatial separation of cardiac afferent and efferent fibers (179±55° SD microCT, p<0.05 and 200±137° SD, p<0.05 sVNS - degrees of separation across a cross-section of nerve) at the mid-cervical level. We also show that cardiac afferent fibers are located in proximity to pulmonary fibers consistent with recent findings of cardiopulmonary convergent neurons and circuits. We demonstrate the ability of sVNS to selectively elicit desired scalable heart rate decrease without stimulating afferent-related reflexes. By elucidating the spatial organization of cardiac-related fibers within the vagus nerve, our findings pave the way for more targeted neuromodulation, thereby reducing off-target effects and eliminating the need for titration. This, in turn, will enhance the precision and efficacy of VNS therapy in treating cardiac pathology, allowing for improved therapeutic efficacy.

Percutaneous cholecystostomy tube placement as a bridge to cholecystectomy for grade III acute cholecystitis: A national analysis

Introduction

Percutaneous cholecystostomy (PCT) is an alternative to cholecystectomy (CCY) in high-risk surgical candidates with severe acute cholecystitis. A subset of these patients ultimately undergo delayed CCY. We therefore compared outcomes of delayed CCY in patients with grade III acute cholecystitis who received a PCT on index admission, to those who did not.

Methods

Non-elective adult hospitalizations for grade III acute cholecystitis that underwent delayed CCY were identified in the 2016-2020 Nationwide Readmission Database. Patients who received a PCT during their index admission comprised the PCT group (others: Non-PCT). Outcomes were assessed for the CCY hospitalization. Entropy balancing was used to generate sample weights to adjust for differences in baseline characteristics. Regression models were created to evaluate the association between PCT and the outcomes of interest.

Results

Of an estimated 13,782 patients, 13.3 % comprised PCT. Compared to Non-PCT, PCT were older (71.1 ± 13.1 vs 67.4 ± 15.3 years) and more commonly in the highest income quartile (22.5 vs 16.1 %, both p < 0.001). After risk adjustment, PCT was associated with reduced odds of respiratory (AOR 0.67, CI 0.54-0.83) and infectious (AOR 0.77, CI 0.62-0.96) complications after eventual CCY. Finally, PCT had comparable pLOS (β +0.31, CI [-0.14, 0.77]) and operative hospitalization costs (β $800, CI [-2300, +600]).

Conclusion

In the present study, PCT was associated with decreased odds of perioperative complications and comparable resource utilization upon readmission CCY. Our findings suggest that PCT may be helpful in bridging patients with grade III acute cholecystitis to eventual CCY.

Center-Level Variation in Failure to Rescue After Pediatric Cardiac Surgery

BACKGROUND

Although failure to rescue (FTR) is increasingly recognized as a quality metric, studies in congenital cardiac surgery remain sparse. Within a national cohort of children undergoing cardiac operations, we characterized the presence of center-level variation in FTR and hypothesized a strong association with mortality but not complications.

METHODS

All children undergoing congenital cardiac operations were identified in the 2013 to 2019 Nationwide Readmissions Database. FTR was defined as in-hospital death after cardiac arrest, ventricular tachycardia/fibrillation, prolonged mechanical ventilation, pneumonia, stroke, venous thromboembolism, or sepsis, among other complications. Hierarchical models were used to generate hospital-specific, risk-adjusted rates of mortality, complications, and FTR. Centers in the highest decile of FTR were identified and compared with others.

RESULTS

Of an estimated 74,070 patients, 1.9% died before discharge, at least 1 perioperative complication developed in 43.0%, and 4.1% experienced FTR. After multilevel modeling, decreasing age, nonelective admission, and increasing operative complexity were associated with greater odds of FTR. Variations in overall mortality and FTR exhibited a strong, positive relationship (r = 0.97), whereas mortality and complications had a negligible association (r = -0.02). Compared with others, patients at centers with high rates of FTR had similar distributions of age, sex, chronic conditions, and operative complexity.

CONCLUSIONS

In the present study, center-level variations in mortality were more strongly explained by differences in FTR than complications. Our findings suggest the utility of FTR as a quality metric for congenital heart surgery, although further study is needed to develop a widely accepted definition and appropriate risk-adjustment models.

National Trends and Clinical Outcomes after Scooter Injury in the US: 2016 to 2020

BACKGROUND

In recent years, the adoption of electric scooters has been accompanied by a surge of scooter-related injuries in the US, raising concerns for their severity and associated healthcare costs. This study aimed to assess temporal trends and outcomes of scooter-related hospital admissions compared with bicycle-related hospitalizations.

STUDY DESIGN

This was a retrospective cohort study using the 2016 to 2020 National Inpatient Sample for patients younger than 65 years who were hospitalized after bicycle- and scooter-related injuries. The Trauma Mortality Prediction Model was used to quantify injury severity. The primary outcomes of interest were temporal trends of micromobility injuries. In-hospital mortality, rates of long bone fracture, traumatic brain injury, paralysis, length of stay, hospitalization costs, and nonhome discharge were secondarily assessed.

RESULTS

Among 92,815 patients included in the study, 6,125 (6.6%) had scooter-related injuries. Compared with patients with bicycle-related injuries, patients with scooter-related injuries were more commonly younger than 18 years (26.7% vs 16.4%, p < 0.001) and frequently underwent major operations (55.8% vs 48.1%, p < 0.001). After risk adjustment, scooter-related injuries were associated with greater risks of long bone fracture (adjusted odds ratio 1.40, 95% CI 1.15 to 1.70) and paralysis (adjusted odds ratio 2.06, 95% CI 1.16 to 3.69) compared with bicycle-related injuries. Additionally, patients with bicycle- or scooter-related injuries had comparable index hospitalization durations of stay and costs.

CONCLUSIONS

The prevalence and severity of scooter-related injuries have significantly increased in the US, thereby attributing to a substantial cost burden on the healthcare system. Multidisciplinary efforts to inform safety policies and enact targeted interventions are warranted to reduce scooter-related injuries.

Center-Level Variation in Hospitalization Costs of Transcatheter Aortic Valve Replacement

BACKGROUND

Using a nationally representative database, the present study evaluated the degree of center-level variation in the cost of transcatheter aortic valve replacement (TAVR).

METHODS

All adults undergoing elective, isolated TAVR were identified in the 2016 to 2018 Nationwide Readmissions Database. Multilevel mixed-effects models were used to identify patient and hospital characteristics associated with hospitalization costs. The random intercept for each hospital was generated and considered to be the baseline cost attributable to care at each center. Hospitals in the highest decile of baseline costs were classified as high-cost hospitals. The association of high-cost hospital status with in-hospital mortality and perioperative complications was subsequently assessed.

RESULTS

An estimated 119,492 patients, with a mean age of 80 years and a 45.9% prevalence of female sex, met the study criteria. Analysis of random intercepts indicated that 54.3% of variability in costs was attributable to interhospital differences rather than patient factors. Perioperative respiratory failure, neurologic complications, and acute kidney injury were associated with increased episodic expenditure but did not explain the observed center-level variation. The baseline cost associated with each hospital ranged from -$26,000 to $162,000. Notably, high-cost hospital status was not linked to annual TAVR caseload or to odds of mortality (P = .83), acute kidney injury (P = .18), respiratory failure (P = .32), or neurologic complications (P = .55).

CONCLUSIONS

The present analysis identified significant variation in the cost of TAVR, which was largely attributable to center-level rather than patient factors. Hospital TAVR volume and occurrence of complications were not drivers of the observed variation.

Prior bariatric surgery is associated with lower mortality and resource utilization following small bowel obstruction

Background

Small bowel obstruction (SBO) is a complication of bariatric surgery. However, outcomes of surgical intervention for SBO among patients with prior bariatric surgery remain ill-defined. We used a nationally representative cohort to characterize the outcomes of the SBO management approach in patients with a prior bariatric operation.

Methods

All adult hospitalizations for SBO were tabulated from the 2018-2020 National Readmissions Database. Patients with a prior history of bariatric surgery comprised the Bariatric cohort (others: Non-Bariatric). Multivariable models were subsequently developed to evaluate the association of prior bariatric surgery with outcomes of interest.

Results

Of an estimated 299,983 hospitalizations for SBO, 15,788 (5.3 %) had a history of prior bariatric surgery. Compared to Non-Bariatric, Bariatric patients were younger (54 [46-62] vs 57 [47-64] years, P < 0.001) and were more frequently privately insured (45.1 vs 39.4 %, P < 0.001). On average, the Bariatric more frequently underwent operative management, relative to Non-Bariatric (44.8 vs 29.7 %, P < 0.001). Following risk adjustment, among those surgically managed, Bariatric demonstrated lower odds of mortality (Adjusted Odds Ratio [AOR] 0.69, 95 % Confidence Interval [CI] 0.55-0.87) compared to Non-Bariatric. Bariatric also demonstrated lower odds of infectious and renal complications. Furthermore, the Bariatric cohort had lower costs, length of stay, and non-home discharge.

Conclusions

Patients with prior bariatric surgery demonstrated a lower likelihood of mortality, decreased complications, and reduced resource utilization, relative to others. As the incidence of bariatric surgery continues to rise, future work is needed to minimize the incidence of SBO among these patients, especially in the current era of value-based healthcare.

National outcomes of expedited discharge following esophagectomy for malignancy

BACKGROUND

Expedited discharge following esophagectomy is controversial due to concerns for higher readmissions and financial burden. The present study aimed to evaluate the association of expedited discharge with hospitalization costs and unplanned readmissions following esophagectomy for malignant lesions.

METHODS

Adults undergoing elective esophagectomy for cancer were identified in the 2014-2019 Nationwide Readmissions Database. Patients discharged by postoperative day 7 were considered Expedited and others as Routine. Patients who did not survive to discharge or had major perioperative complications were excluded. Multivariable regression models were constructed to assess association of expedited discharge with index hospitalization costs as well as 30- and 90-day non-elective readmissions.

RESULTS

Of 9,886 patients who met study criteria, 34.6% comprised the Expedited cohort. After adjustment, female sex (adjusted odds ratio [AOR] 0.71, p = 0.001) and increasing Elixhauser Comorbidity Index (AOR 0.88/point, p<0.001) were associated with lower odds of expedited discharge, while laparoscopic (AOR 1.63, p<0.001, Ref: open) and robotic (AOR 1.67, p = 0.003, Ref: open) approach were linked to greater likelihood. Patients at centers in the highest-tertile of minimally invasive esophagectomy volume had increased odds of expedited discharge (AOR 1.52, p = 0.025, Ref: lowest-tertile). On multivariable analysis, expedited discharge was independently associated with an $8,300 reduction in hospitalization costs. Notably, expedited discharge was associated with similar odds of 30-day (AOR 1.10, p = 0.40) and 90-day (AOR 0.90, p = 0.70) unplanned readmissions.

CONCLUSION

Expedited discharge after esophagectomy was associated with decreased costs and unaltered readmissions. Prospective studies are necessary to robustly evaluate whether expedited discharge is appropriate for select patients undergoing esophagectomy.

Association of prior bariatric surgery with outcomes following emergency general surgery

BACKGROUND

Despite the favorable outcomes and safety profile associated with metabolic and bariatric surgery (MBS), complications may occur postoperatively, necessitating emergency general surgery (EGS) intervention.

OBJECTIVES

To evaluate the association of outcomes in patients with prior MBS following EGS interventions.

SETTING

Academic, University-affiliated; USA.

METHODS

All adults undergoing nonelective EGS operations were identified using the 2016 to 2020 Nationwide Readmission Database. Patients with a history of MBS were subsequently categorized as Bariatric, with the remainder of patients as NonBariatric. The primary outcome of interest was in-hospital mortality, while perioperative complications, length of stay (LOS), hospitalization costs, non-home discharge, and 30-day readmission were secondarily assessed. Multivariable regression models were developed to evaluate the association of history of MBS with outcomes of interest.

RESULTS

Of an estimated 632,375 hospitalizations for EGS operations, 29,112 (4.6%) had a history of MBS. Compared to Nonbariatric, Bariatric were younger, more frequently female and more commonly had severe obesity. Following risk adjustment, Bariatric had significantly lower odds of in-hospital mortality (AOR .83, 95%CI .71-.98). Compared to others, Bariatric had reduced LOS by .5 days (95%CI .4-.7) and hospitalization costs by $1600 (95%CI $900-2100). Patients with prior MBS had reduced odds of nonhome discharge (AOR .89, 95%CI .85-.93) and increased likelihood of 30-day readmissions (AOR 2.32, 95%CI 1.93--2.79) following EGS.

CONCLUSIONS

Prior MBS is associated with decreased mortality and perioperative complications as well as reduced resource utilization in select EGS procedures. Our findings suggest that patients with a history of MBS can be managed effectively by acute surgical interventions.

Association of prior bariatric surgery with financial and clinical outcomes of acute myocardial infarction

BACKGROUND

Superior clinical outcomes after hospitalization for cardiovascular-related disease such as acute heart failure have been linked with prior history of bariatric surgery, but similar analyses in acute myocardial infarction (MI) are currently limited.

OBJECTIVE

This work examines clinical outcomes and resource utilization in patients with acute MI hospitalizations with a prior history of bariatric surgery.

SETTING

Academic university-affiliated hospital in the United States.

METHODS

All adult patients with hospitalizations with a primary diagnosis of acute MI were queried using the 2016-2020 Nationwide Readmissions Database. The study population was comprised of patients with an International Classification of Diseases, Tenth Revision (ICD-10) diagnosis code for obesity (body mass index ≥35 kg/m2) as well as those with a prior history of bariatric surgery regardless of their body mass index status. Comparison was made between those with a prior history of bariatric surgery and those without. Univariate analysis and multivariate regression models were used to examine the association between bariatric surgery and outcomes of interest, which included in-hospital mortality, medical complications, and resource utilization.

RESULTS

Of an estimated 2,736,606 hospitalizations for acute MI, 296,902 patients (10.8%) had a diagnosis of obesity and/or a prior history of bariatric surgery. The bariatric cohort was more frequently female and had a lower prevalence of congestive heart failure, chronic lung disease, diabetes, and electrolyte derangements than the nonbariatric cohort. After risk adjustment, prior history of bariatric surgery was associated with significantly lower odds of in-hospital mortality, cardiogenic shock, and acute kidney injury. Additionally, prior history of bariatric surgery was linked to a decreased duration of hospital stay and lower hospitalization costs as well as lower odds of nonhome discharge.

CONCLUSION

Among acute MI patients with obesity, prior history of bariatric surgery was associated with decreased odds of in-hospital mortality, improved clinical outcomes, and lower resource utilization. Expansion of bariatric surgery programs may provide improved access to a medical intervention that is intertwined with cardiovascular health.

Association of frailty with postoperative outcomes following thoracic transplantation: A national analysis

Objective

Frailty has been repeatedly associated with inferior outcomes after surgical hospitalizations. However, a thorough evaluation of the impact of frailty on the clinical and financial outcomes of patients undergoing solid-organ thoracic transplantation is sparse in the literature. We evaluated the association of frailty, as determined by an administrative tool, with postoperative outcomes and healthcare resource use after heart or lung transplantation.

Methods

The Nationwide Readmissions Database was used to identify all adult hospitalizations for heart or lung transplant from 2014 to 2020. Patients were grouped as frail or nonfrail using International Classification of Diseases codes associated with conditions in the Johns Hopkins Adjusted Clinical Groups cluster. Multivariable regression models were developed to evaluate the association of frailty status on in-hospital mortality, complications, length of stay, costs, and unplanned readmissions.

Results

Of an estimated 35,862 heart or lung transplant recipients, 7316 (20.4%) were considered frail. After multivariable adjustment, frailty in heart transplantation was associated with greater odds of in-hospital mortality (adjusted odds ratio, 1.54; 95% CI, 1.19-1.99) and infectious complications (adjusted odds ratio, 1.77; 95% CI, 1.45-2.15; P < .001). Frailty in lung transplantation was also associated with higher odds of in-hospital mortality (adjusted odds ratio, 1.38; 95% CI, 1.11-1.69) and infectious complications (adjusted odds ratio, 1.93; 95% CI, 1.60-2.31). In addition, frailty in both heart transplantation and lung transplantation was associated with increased postoperative length of stay and greater costs.

Conclusions

Among transplant recipients, those classified as frail were associated with increased in-hospital mortality, perioperative complications, and resource use.

Center-Level Variation in Failure to Rescue After Elective Adult Cardiac Surgery

BACKGROUND

There has been increasing emphasis on evaluation of failure to rescue (FTR) after major inpatient operations. The present study characterized center-level variation in FTR within a national cohort of patients undergoing elective cardiac operations.

METHODS

All adults undergoing elective coronary artery bypass grafting and/or valve operations were identified in the 2016-2019 Nationwide Readmissions Database. FTR was defined as in-hospital death after prolonged mechanical ventilation, stroke, reoperation, acute kidney injury requiring dialysis, sepsis, cardiac arrest or pulmonary embolism. Multi-level, mixed-effects regressions were used to model mortality, complications, and FTR. Centers with high hospital-specific rates of FTR (≥95th percentile) were identified and compared to others.

RESULTS

Of an estimated 454,506 patients included for analysis, 32,537 (7.2%) developed at least 1 complication, and 7669 (1.7%) died before discharge. Overall, 5370 (16.5%) patients experienced FTR. Compared with those who developed ≥1 complication but survived to discharge, FTR patients were significantly older, more commonly female, and had a greater burden of comorbidities as measured by the Elixhauser Comorbidity Index. Risk-adjusted, hospital-specific rates of mortality and FTR were moderately correlated (r = 0.64), mortality and complications were weakly associated (r = 0.16), and complications and FTR exhibited a very weak relationship (r = -0.02). Relative to others, centers with high rates of FTR had lower annual cardiac surgical volume (median 61 [interquartile range 33-133] vs 80 [interquartile range 43-149] cases/y, P = .019).

CONCLUSIONS

The present findings affirm prior work demonstrating a close link between variation in FTR and mortality, but not complications. Further study is necessary to delineate modifiable care pathways that mitigate FTR.

Machine Learning Based Prediction of Postoperative Pancreatic Fistula Following Pancreaticoduodenectomy

OBJECTIVE

To develop a novel machine learning (ML) model to predict clinically relevant postoperative pancreatic fistula (CR-POPF) following pancreaticoduodenectomy (PD).

SUMMARY BACKGROUND DATA

Accurate prognostication of CR-POPF may allow for risk stratification and adaptive treatment strategies for potential PD candidates. However, antecedent models, such as the modified Fistula Risk Score (mFRS), are limited by poor discrimination and calibration.

METHODS

All records entailing PD within the 2014-2018 ACS NSQIP were identified. Additionally, patients undergoing PD at our institution between 2013 and 2021 were queried from our local data repository. An eXtreme Gradient Boosting (XGBoost) model was developed to estimate the risk of CR-POPF using data from the ACS NSQIP and evaluated using institutional data. Model discrimination was estimated using the area under the receiver operating characteristic (AUROC) and precision recall curve (AUPRC).

RESULTS

Overall, 12,281 and 445 patients undergoing PD were identified within the 2014-2018 ACS NSQIP and our institutional registry, respectively. Application of the XGBoost and mFRS scores to the internal validation dataset revealed that the former model had significantly greater AUROC (0.72 vs. 0.68, P<0.001) and AUPRC (0.22 vs. 0.18, P<0.001). Within the external validation dataset, the XGBoost model remained superior to the mFRS with an AUROC of 0.79 (95% CI 0.74-0.84) versus 0.75 (95% CI 0.70-0.80, P<0.001). In addition, AUPRC was higher for the XGBoost model, compared to the mFRS.

CONCLUSIONS

Our novel ML model consistently outperformed the previously validated mFRS within internal and external validation cohorts, thereby demonstrating its generalizability and utility for enhancing prediction of CR-POPF.

Impact of surgeon specialty on clinical outcomes following esophagectomy for cancer

BACKGROUND

The impact of surgeon and hospital operative volume on esophagectomy outcomes is well-described; however, studies examining the influence of surgeon specialty remain limited. Therefore, we evaluated the impact of surgeon specialty on short-term outcomes following esophagectomy for cancer.

METHODS

The 2016-2019 American College of Surgeons National Surgical Quality Improvement Project (ACS NSQIP) was queried to identify all patients undergoing esophagectomy for esophageal cancer. Surgeon specialty was categorized as general (GS) or thoracic (TS). Entropy balancing was used to generate sample weights that adjust for baseline differences between GS and TS patients. Weights were subsequently applied to multivariable linear and logistic regressions, which were used to evaluate the independent association of surgeon specialty with 30-day mortality, complications, and postoperative length of stay.

RESULTS

Of 2657 esophagectomies included for analysis, 54.1% were performed by TS. Both groups had similar distributions of age, sex, and body mass index. TS patients more frequently underwent transthoracic esophagectomy, while GS patients more commonly received minimally invasive surgery. After adjustment, surgeon specialty was not associated with altered odds of 30-day mortality (adjusted odds ratio [AOR] 1.10 p = 0.73) or anastomotic leak (AOR 0.87, p = 0.33). However, TS patients exhibited a 40-min reduction in operative duration and faced greater odds of perioperative transfusion, relative to GS.

CONCLUSION

Among ACS NSQIP participating centers, surgeon specialty influenced operative duration and blood product utilization, but not mortality and anastomotic leak. Our results support the relative safety of esophagectomy performed by select GS and TS.

Association of body mass index with 30-day outcomes following groin hernia repair

PURPOSE

Although groin hernia repairs are relatively safe, efforts to identify factors associated with greater morbidity and resource utilization following these operations are warranted. An emphasis on obesity has limited studies from a comprehensive evaluation of the association between body mass index (BMI) and outcomes following groin hernia repair. Thus, we aimed to ascertain the association between BMI class with 30-day outcomes following these operations.

METHODS

The 2014-2020 National Surgical Quality Improvement Program database was queried to identify adults undergoing non-recurrent groin hernia repair. Patient BMI was used to stratify patients into six groups: underweight, normal, overweight, and obesity classes I-III. Association of BMI with major adverse events (MAE), wound complication, and prolonged length of stay (pLOS) as well as 30-day readmission and reoperation were evaluated using multivariable regressions.

RESULTS

Of the 163,373 adults who underwent groin hernia repair, the majority of patients were considered overweight (44.4%). Underweight patients more commonly underwent emergent operations and femoral hernia repair compared to others. After adjustment of intergoup differences, obesity class III was associated with greater odds of an MAE (AOR 1.50), wound complication (AOR 4.30), pLOS (AOR 1.40), and 30-day readmission (AOR 1.50) and reoperation (AOR 1.75, all p < 0.05). Underweight BMI portended greater odds of pLOS and unplanned readmission.

CONCLUSION

Consideration of BMI in patients requiring groin hernia repair could help inform perioperative expectations. Preoperative optimization and deployment of a minimally invasive approach when feasible may further reduce morbidity in patients at the extremes of the BMI spectrum.

Dementia is Associated With Inferior Outcomes Following Emergency General Surgery

INTRODUCTION

Given the steadily aging United States population, we used a national database to examine the association of dementia with clinical and financial outcomes following emergency general surgery.

METHODS

All adults undergoing non-elective appendectomy, cholecystectomy, small bowel resection, large bowel resection, repair of perforated ulcer, or lysis of adhesions were identified within the 2016-2019 Nationwide Readmissions Database. Entropy balancing and multivariable regressions were used to assess the risk-adjusted association between dementia and in-hospital mortality, complications, length of stay, costs, non-home discharge, and 30-day unplanned readmissions.

RESULTS

Of an estimated 1,332,922 patients, 2.7% had dementia. Compared to those without, patients with dementia were older, more commonly male, and had a greater burden of chronic conditions. Following entropy balancing and multivariable risk-adjustment, dementia was associated with increased odds of mortality and sepsis across all operations except perforated ulcer repair. Dementia was also linked to greater likelihood of pneumonia across all operative categories. Moreover, dementia was associated with increased length of stay for patients in all operative categories except perforated ulcer repair, while costs were only increased for those undergoing appendectomy, cholecystectomy, and lysis of adhesions. Dementia was also linked to higher odds of non-home discharge following all operations, while non-elective readmissions were only increased for patients undergoing cholecystectomy.

CONCLUSIONS

The present study found dementia to be associated with a significant clinical and financial burden. Our findings may help inform shared decision making with patients and their families.

Vagal Nerve Stimulation Reduces Ventricular Arrhythmias and Mitigates Adverse Neural Cardiac Remodeling Post-Myocardial Infarction

This study sought to evaluate the impact of chronic vagal nerve stimulation (cVNS) on cardiac and extracardiac neural structure/function after myocardial infarction (MI). Groups were control, MI, and MI + cVNS; cVNS was started 2 days post-MI. Terminal experiments were performed 6 weeks post-MI. MI impaired left ventricular mechanical function, evoked anisotropic electrical conduction, increased susceptibility to ventricular tachycardia and fibrillation, and altered neuronal and glial phenotypes in the stellate and dorsal root ganglia, including glial activation. cVNS improved cardiac mechanical function and reduced ventricular tachycardia/ventricular fibrillation post-MI, partly by stabilizing activation/repolarization in the border zone. MI-associated extracardiac neural remodeling, particularly glial activation, was mitigated with cVNS.

Association of Hospital Volume and Outcomes Following Off-Pump Coronary Artery Bypass Grafting

BACKGROUND

Off-pump coronary artery bypass grafting (OPCAB) has been used to mitigate the negative systemic effects of cardiopulmonary bypass. Recent consortium and single-institution studies suggest an association between operator experience and long-term survival. We thus aimed to ascertain the relationship between institutional OPCAB volume and outcomes using a contemporary nationwide all-payer database.

METHODS

Adult admissions for elective isolated OPCAB were identified from the 2016-2019 Nationwide Readmissions Database. The primary outcome was major adverse events (MAE), defined as a composite of mortality, reoperation, prolonged mechanical ventilation, acute kidney injury requiring dialysis, or perioperative stroke during the index hospitalisation. Secondary outcomes included temporal trends, postoperative length of stay (pLOS), hospitalisation costs, non-home discharge, and 30-day readmission rate. High-volume hospitals (HVH) were defined to have annual caseloads >35 based on cubic spline analysis.

RESULTS

Of an estimated 41,154 patients, 59.9% were treated at HVH. The proportion of coronary artery bypass grafting operations that were OPCAB significantly decreased from 21.1% in 2016 to 18.3% in 2019. After adjustment, HVH status was associated with lower adjusted odds of MAE (adjusted odds ratio [AOR] 0.78, 95% confidence interval [CI] 0.70-0.88), compared to others. HVH were also associated with shorter pLOS (β -0.10, 95% -0.13, -0.07), reduced costs (β -US$4,900, - US$6,300, - US$3,600), non-home discharge (AOR 0.54, 95% CI 0.45-0.64), and 30-day readmission (AOR 0.86, 95% CI 0.77-0.96).

CONCLUSIONS

Our results suggest that OPCAB requires a distinct set of surgical expertise and institutional aptitude. As a result, centralisation of care to centres of excellence should be considered.

Impact of Pulmonary Complications on Outcomes and Resource Use After Elective Cardiac Surgery

OBJECTIVE

To characterize the impact of pulmonary complications (PCs) on mortality, costs, and readmissions after elective cardiac operations in a national cohort and to test for hospital-level variation in PC.

BACKGROUND

PC after cardiac surgery are targets for quality improvement efforts. Contemporary studies evaluating the impact of PC on outcomes are lacking, as is data regarding hospital-level variation in the incidence of PC.

METHODS

Adults undergoing elective coronary artery bypass grafting and/or valve operations were identified in the 2016-2019 Nationwide Readmissions Database. PC was defined as a composite of reintubation, prolonged (>24 hours) ventilation, tracheostomy, or pneumonia. Generalized linear models were fit to evaluate associations between PC and outcomes. Institutional variation in PC was studied using observed-to-expected ratios.

RESULTS

Of 588,480 patients meeting study criteria, 6.7% developed PC. After risk adjustment, PC was associated with increased odds of mortality (14.6, 95% CI, 12.6-14.8), as well as a 7.9-day (95% CI, 7.6-8.2) increase in length of stay and $41,300 (95% CI, 39,600-42,900) in attributable costs. PC was associated with 1.3-fold greater hazard of readmission and greater incident mortality at readmission (6.7% vs 1.9%, P <0.001). Significant hospital-level variation in PC was present, with observed-to-expected ratios ranging from 0.1 to 7.7.

CONCLUSIONS

Pulmonary complications remain common after cardiac surgery and are associated with substantially increased mortality and expenditures. Significant hospital-level variation in PC exists in the United States, suggesting the need for systematic quality improvement efforts to reduce PC and their impact on outcomes.

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

BACKGROUND

Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.

METHODS

This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low-middle-income countries.

RESULTS

In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of 'single-use' consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low-middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.

CONCLUSION

This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high- and low-middle-income countries.

Association of insurance status with financial toxicity and outcome disparities after penetrating trauma and assault

BACKGROUND

Financial toxicity, or the impact out-of-pocket medical expenses have on the quality of life, has not been widely enumerated in the trauma literature. We characterized the relationship between insurance status and the risk of financial toxicity after trauma and associated risk factors.

METHODS

Adults admitted for gunshot wounds, other penetrating injuries, or blunt assault were identified from the 2015 to 2019 National Inpatient Sample. The outcome of interest was a risk of financial toxicity with separate regression models for uninsured and insured populations.

RESULTS

Of an estimated 775,665 patients, 21.2% were at risk of financial toxicity. Patients at risk of financial toxicity were younger, more commonly male, less commonly White, and had a lower Elixhauser Index (Table 1). A higher proportion of uninsured patients were at risk of financial toxicity (40.8% vs 17.7%, P < .001) than insured patients. Whereas the proportion of uninsured patients at risk of financial toxicity significantly increased from 2015 to 2019, it was unchanged in insured patients. After adjustment, non-income demographic and clinical factors were not associated with the risk of financial toxicity amongst the insured. Conversely, the Black or Hispanic race, gunshot wounds, and any in-hospital complications were some factors associated with increased risk of financial toxicity in uninsured patients.

CONCLUSION

An increasingly larger proportion of uninsured patients are at risk of financial toxicity after trauma. The risk of financial toxicity among the uninsured was more complex than in the insured and associated with race, gunshot wounds, and complications. Increasing insurance access and the adoption of trauma-informed care practices should be used to address financial toxicity in this population.

Volume-outcome relationship in septal myectomy for hypertrophic obstructive cardiomyopathy

BACKGROUND

Septal myectomy is the gold standard treatment for refractory hypertrophic obstructive cardiomyopathy. The present study characterized the association of septal myectomy volume and cardiac surgery volume with outcomes after septal myectomy.

METHODS

Adults undergoing septal myectomy for hypertrophic obstructive cardiomyopathy were identified in the 2016 to 2019 Nationwide Readmissions Database. Centers were grouped into low-, medium-, and high-volume hospitals by tertiles based on institutional septal myectomy caseload. Overall cardiac surgery volume was similarly assessed. Generalized linear models were used to test the association between hospital septal myectomy or cardiac surgery volume and in-hospital mortality, mitral valve repair, and 90-day non-elective readmission.

RESULTS

Of 3,337 patients, 30.8% underwent septal myectomy at high-volume hospitals, whereas 39.1% were managed at low-volume hospitals. Patients at high-volume hospitals had a similar burden of comorbidities at low-volume hospitals, although congestive heart failure was more prevalent at high-volume hospitals. Despite comparable rates of mitral regurgitation, patients more commonly avoided mitral valve intervention at high-volume hospitals compared with low-volume hospitals (72.9% vs 68.3%; P = .007). After risk adjustment, high-volume hospital status was associated with reduced odds of mortality (0.24; 95% CI, 0.08-0.77) and readmission (0.59; 95% CI, 0.3-0.97). Among cases requiring mitral intervention, high-volume hospital status was associated with greater odds of valve repair (5.33; 95% CI, 2.54-11.13) relative to low-volume hospitals. Overall cardiac surgery volume was not associated with any studied outcome.

CONCLUSION

Greater septal myectomy volume, but not overall cardiac surgery volume, was associated with reduced mortality and greater mitral valve repair relative to replacement after septal myectomy. These findings suggest that septal myectomy for hypertrophic obstructive cardiomyopathy should be performed at centers with expertise in this operation.

Contemporary association of preoperative malnutrition and outcomes of hiatal hernia repairs in the United States

BACKGROUND

Hypoalbuminemia has been used as a surrogate for malnutrition and is associated with worse postoperative outcomes across major operations. Because patients with hiatal hernia often have inadequate caloric intake, we examined the association of serum albumin levels with outcomes after hiatal hernia repair.

METHODS

Adults undergoing elective and non-elective hiatal hernia repair via any approach were tabulated from the 2012 to 2019 National Surgical Quality Improvement Program. Patients were stratified into the Hypoalbuminemia cohort if serum albumin <3.5 mg/dL using restricted cubic spline analysis. Major adverse events were defined as a composite of all-cause mortality and major complications per the American College of Surgeons National Surgical Quality Improvement Program risk calculator. Entropy balancing was used to adjust for intergroup differences. Multivariable regression models were then constructed to assess the association of preoperative albumin with major adverse events, postoperative length of stay, and 30-day readmission.

RESULTS

Of 23,103 patients, 11.7% comprised the Hypoalbuminemia cohort. The Hypoalbuminemia group was older, less commonly of White race, and less likely to have an independent functional status than others. They were also more likely to undergo inpatient, non-elective surgery via laparotomy. After entropy balancing and adjustment, hypoalbuminemia remained associated with increased odds of major adverse events and multiple complications and longer adjusted postoperative length of stay. There was no significant difference in adjusted odds of readmission.

CONCLUSION

We used a quantitative methodology to establish a serum albumin threshold of 3.5 mg/dL associated with increased adjusted odds of major adverse events, increased postoperative length of stay, and postoperative complications after hiatal hernia repair. These results may guide preoperative nutrition supplementation.

Clinical and financial outcomes of pulmonary resection for lung cancer in safety-net hospitals

OBJECTIVE

Safety-net hospitals (SNHs) have previously been associated with inferior outcomes and greater resource use. However, this relationship has not been explored in the contemporary setting of pulmonary lobectomy. In the present national study we characterized the association between SNHs and mortality, complications, and resource use.

METHODS

All adults (18 years of age or older) who underwent elective lobectomy for lung cancer were identified within the 2010 to 2019 Nationwide Readmissions Database. Hospitals in the highest quartile of safety-net burden were categorized as SNHs, and others non-SNHs. Multivariable regressions were developed to assess the independent association between safety-net status and outcomes of interest.

RESULTS

Of an estimated 282,011 patients who met inclusion criteria, 41,015 (14.5%) were treated at SNHs. Patients at SNHs were younger but as commonly female, compared with non-SNHs. After multivariable adjustment, there was no association between SNHs and mortality. However, treatment at SNHs was linked to higher odds of pneumonia (adjusted odds ratio [AOR], 1.11; 95% CI, 1.02-1.21) and prolonged ventilation (AOR, 1.36; 95% CI, 1.11-1.66), as well as infectious (AOR, 1.24; 95% CI, 1.08-1.43), intraoperative (AOR, 1.22; 95% CI, 1.07-1.39), and overall complications (AOR, 1.07; 95% CI, 1.01-1.14). Patients at SNHs also showed a greater need for a blood transfusion (AOR, 1.37; 95% CI, 1.23-1.53). In addition, SNHs were associated with increased length of stay (+0.33 days; 95% CI, 0.17-0.48) and greater costs (+$4130; 95% CI, 3.34-4.92), relative to non-SNHs.

CONCLUSIONS

Hospital safety-net status was associated with greater odds of perioperative complications and greater health care expenditure. Further investigation is necessary uncover the mechanisms contributing to these complications and eradicate persistent disparities in lobectomy.

A contemporary analysis of the volume-outcome relationship for extracorporeal membrane oxygenation in the United States

BACKGROUND

A paradoxical increase in mortality following extracorporeal membrane oxygenation at high-volume centers has previously been demonstrated. We examined the association between annual hospital volume and outcomes within a contemporary, national cohort of extracorporeal membrane oxygenation patients.

METHODS

All adults requiring extracorporeal membrane oxygenation for postcardiotomy syndrome, cardiogenic shock, respiratory failure, or mixed cardiopulmonary failure were identified in the 2016 to 2019 Nationwide Readmissions Database. Patients undergoing heart and/or lung transplantation were excluded. A multivariable logistic regression with hospital extracorporeal membrane oxygenation volume parametrized as restricted cubic splines was developed to characterize the risk-adjusted association between volume and mortality. The volume corresponding to the maximum of the spline (43 cases/year) was used to categorize centers as low- or high-volume.

RESULTS

An estimated 26,377 patients met the study criteria, and 48.7% were managed at high-volume hospitals. Patients at low- and high-volume hospitals had similar age, sex, and rates of elective admission. Notably, patients at high-volume hospitals less frequently required extracorporeal membrane oxygenation for postcardiotomy syndrome but more commonly for respiratory failure. After risk adjustment, high-volume hospital status was associated with reduced odds of in-hospital mortality, relative to low-volume hospitals (adjusted odds ratio 0.81, 95% confidence interval 0.78-0.97). Interestingly, patients at high-volume hospitals faced a 5.2-day increment in length of stay (95% confidence interval 3.8-6.5) and $23,500 in attributable costs (95% confidence interval 8,300-38,700).

CONCLUSION

The present study found that greater extracorporeal membrane oxygenation volume was associated with decreased mortality but higher resource use. Our findings may help inform policies regarding access to and centralization of extracorporeal membrane oxygenation care in the United States.

Preoperative stents for the treatment of obstructing left-sided colon cancer: a national analysis

BACKGROUND

Given the risks associated with urgent colectomy for large bowel obstruction, preoperative colonic stenting has been utilized for decompression and optimization prior to surgery. This study examined national trends in the use of colonic stenting as a bridge to resection for malignant large bowel obstruction and evaluated outcomes relative to immediate colectomy.

METHODS

Adults undergoing colonic stenting or colectomy for malignant, left/sigmoid large bowel obstruction were identified in the 2010-2016 Nationwide Readmissions Database. Patients were classified as immediate resection (IR) or delayed resection (DR) if undergoing colonic stenting prior to colectomy. Generalized linear models were used to evaluate the impact of resection strategy on ostomy creation, in-hospital mortality, and complications.

RESULTS

Among 9,706 patients, 9.7% underwent colonic stenting, which increased from 7.7 to 16.4% from 2010 to 2016 (p < 0.001). Compared to IR, the DR group was younger (63.9 vs 65.9 years, p = 0.04), had fewer comorbidities (Elixhauser Index 3.5 vs 3.9, p = 0.001), and was more commonly managed at high-volume centers (89.4% vs 68.1%, p < 0.001). Laparoscopic resections were more frequent among the DR group (33.1% vs 13.0%, p < 0.001), while ostomy rates were significantly lower (21.5% vs 53.0%, p < 0.001). After risk adjustment, colonic stenting was associated with reduced odds of ostomy creation (0.34, 95% confidence interval 0.24-0.46), but similar odds of mortality and complications.

CONCLUSION

Colonic stenting is increasingly utilized for malignant, left-sided bowel obstructions, and associated with lower ostomy rates but comparable clinical outcomes. These findings suggest the relative safety of colonic stenting for malignant large bowel obstruction when clinically appropriate.

Cost Variation and Value of Care in Pulmonary Lobectomy Across the United States

BACKGROUND

Optimization of value, or quality relative to costs, has garnered significant attention in the United States. We aimed to characterize center-level variation in costs and quality after pulmonary lobectomy using a national cohort.

METHODS

Adults undergoing elective pulmonary lobectomy were identified in the 2016 to 2018 Nationwide Readmissions Database. Quality was defined by the absence of major adverse outcomes including respiratory failure, acute kidney injury, reoperation, and death. Risk-adjusted adverse outcome rates and costs were studied for institutions performing greater than or equal to 10 operations annually. Using observed-to-expected (O/E) ratios, high-value hospitals were defined as those with an O/E ratio less than 1 for costs and O/E ratio less than 1 for quality, while low-value hospitals were defined by the converse.

RESULTS

Among 95 446 patients managed at 565 hospitals annually, the median center-level cost for lobectomy was $22 000 (interquartile range, $18 000-$27 000), while the median adverse outcome rate was 14.3% (interquartile range, 8.3%-23.1%). Centers with an O/E ratio less than 1 for adverse events exhibited a $2200/case reduction in risk-adjusted costs. Using O/E ratios, 35.2% of centers were classified as high value while 18.6% were low value. Compared with low-value centers, high-value centers treated older patients (67.1 years of age vs 65.5 years of age; P < .001) with greater comorbidities (Elixhauser Comorbidity Index 3.7 vs 2.9; P < .001) but had greater annual lobectomy volume (40 cases vs 30 cases; P = .001) and were more commonly teaching hospitals.

CONCLUSIONS

Significant variation in costs and quality persists for lobectomy at the national level. Although high-value programs operated on patients at greater surgical risk, they had reduced complications and costs. Our findings suggest the need for dissemination of quality improvement and cost reduction practices.

Regional Variation in the Use and Outcomes of Transcatheter Aortic Valve Replacement in California

BACKGROUND

Transcatheter aortic valve replacement (TAVR) has been widely adopted for management of aortic stenosis. The purpose of this study was to examine regional access to and outcomes following TAVR in California.

METHODS

Patients undergoing TAVR or isolated surgical aortic valve replacement (SAVR) from 2008 to 2019 in California were identified in the Office of Statewide Health Planning and Development database. California was divided into seven regions: Northern California, San Francisco Bay Area, Central California, Los Angeles, Inland Empire, Orange, and San Diego. Regional TAVR volumes were normalized to Medicare beneficiaries or isolated SAVR volume. Outcomes included risk-adjusted 30-day mortality and major adverse cardiovascular and cerebral events (MACCE). Trends were studied using non-parametric tests, and regional outcomes using logistic regression.

RESULTS

TAVR volume increased annually since 2011, with 7148 cases performed in California in 2019. After normalization, variation in utilization of TAVR was evident, with the least performed in Central California. TAVR to SAVR ratios in 2019 were greatest in Northern California, Los Angeles, and San Diego, and least in the Inland Empire. After risk adjustment, there were no significant regional differences in 30-day mortality, but lower 30-day MACCE in the San Francisco Bay Area.

CONCLUSIONS

Regional differences in TAVR utilization exist, with limited access in Central California and the Inland Empire, but risk-adjusted outcomes are similar. Efforts to reach underserved areas through existing program expansion or regional referrals may distribute transcatheter technology more equitably across California.

Impact of inter-hospital transfer on outcomes of urgent cholecystectomy

BACKGROUND

This study used a national cohort to characterize the impact of inter-hospital transfer status on outcomes following nonelective cholecystectomy for cholecystitis.

METHODS

Nonelective cholecystectomies were identified using the 2016-2019 National Inpatient Sample. Multivariable models adjusting for patient and hospital characteristics were utilized to assess outcomes of interest.

RESULTS

Of an estimated 530,696 patients, 5.3% were transferred. Transferred patients were older, more often male, and more likely to report income in the 0^th-25th percentile, compared to others. After adjustment, transfer was associated with increased odds of infectious complications (AOR 1.31, 95%CI 1.06-1.60) and non-home discharge (AOR 1.59, 95%CI 1.45-1.74), but not mortality. Transfer was linked to a $600 cost decrement at the operating hospital (95%CI -$880-330).

CONCLUSIONS

Transfer status is associated with greater postoperative infection, but not mortality. Given that disparities may play a role in transfer decisions, more work must be done to identify transfer drivers and improve patient outcomes.

Sympathetic innervation of human and porcine spleens: implications for between species variation in function

BACKGROUND

The vagus nerve affects innate immune responses by activating spleen-projecting sympathetic neurons, which modulate leukocyte function. Recent basic and clinical research investigating vagus nerve stimulation to engage the cholinergic anti-inflammatory pathway (CAP) has shown promising therapeutic results for a variety of inflammatory diseases. Abundant sympathetic innervation occurs in rodent spleens, and use of these species has dominated mechanistic research investigating the CAP. However, previous neuroanatomical studies of human spleen found a more restricted pattern of innervation compared to rodents. Therefore, our primary goal was to establish the full extent of sympathetic innervation of human spleens using donor tissue with the shortest procurement to fixation time. Parallel studies of porcine spleen, a large animal model, were performed as a positive control and for comparison.

METHODS

Human and porcine spleen tissue were fixed immediately after harvest and prepared for immunohistochemistry. Human heart and porcine spleen were stained in conjunction as positive controls. Several immunohistochemical protocols were compared for best results. Tissue was stained for tyrosine hydroxylase (TH), a noradrenergic marker, using VIP purple chromogen. Consecutive tissue slices were stained for neuropeptide Y (NPY), which often co-localizes with TH, or double-labelled for TH and CD3, a T cell marker. High-magnification images and full scans of the tissue were obtained and analyzed for qualitative differences between species.

RESULTS

TH had dominant perivascular localization in human spleen, with negligible innervation of parenchyma, but such nerves were abundant throughout ventricular myocardium. In marked contrast, noradrenergic innervation was abundant in all regions of porcine spleen, with red pulp having more nerves than white pulp. NPY stain results were consistent with this pattern. In human spleen, noradrenergic nerves only ran close to T cells at the boundary of the periarterial lymphatic sheath and arteries. In porcine spleen, noradrenergic nerves were closely associated with T cells in both white and red pulp as well as other leukocytes in red pulp.

CONCLUSION

Sympathetic innervation of the spleen varies between species in both distribution and abundance, with humans and pigs being at opposite extremes. This has important implications for sympathetic regulation of neuroimmune interactions in the spleen of different species and focused targeting of the CAP in humans.

Left Atrial Appendage Closure During Cardiac Surgery: Safe but Underutilized in California

Objective

Left atrial appendage (LAA) closure is associated with reduced rates of stroke in patients with atrial fibrillation (AF). We evaluated trends in LAA closure, the association of LAA closure with stroke/systemic embolism, and its safety profile in patients with AF who underwent cardiac surgery in California. We further tested for hospital-level variation in concomitant LAA closure.

Methods

Adults who underwent coronary artery bypass grafting and/or valve surgery with preoperative AF were identified in the 2016 to 2019 Office of Statewide Health Planning and Development databases. Propensity score matching was performed to study risk-adjusted associations of LAA closure with ischemic stroke/systemic embolism. Hospital-level variation was studied using intraclass correlation coefficients.

Results

Among 18,434 patients with AF who underwent coronary artery bypass grafting/valve surgery, 47.7% received LAA closure. Rates of LAA closure increased from 44.4% to 51.4% from 2016 to 2019 (P < .001). In 4652 propensity score-matched patients, LAA closure was associated with reduced incidence of stroke/systemic embolism at discharge (1.6% vs 3.1%; P < .001) and readmission with stroke/systemic embolism at 1 year (2.9% vs 4.5%; P = .004). LAA closure was not associated with acute kidney injury, pulmonary complications, blood transfusion, reoperation, or in-hospital mortality. Approximately 18% of the risk-adjusted variation in LAA use was attributed to the hospital, with median center-level rate of 44.9% (interquartile range, 29.6%-57.4%).

Conclusions

LAA closure was associated with minimal surgical morbidity, and reduced short- and midterm incidence of stroke/systemic embolism. Although the use of LAA closure has increased, substantial variation exists among programs in California, suggesting the need for further standardization of care.

Metrics of high cofluctuation and entropy to describe control of cardiac function in the stellate ganglion

Stellate ganglia within the intrathoracic cardiac control system receive and integrate central, peripheral, and cardiopulmonary information to produce postganglionic cardiac sympathetic inputs. Pathological anatomical and structural remodeling occurs within the neurons of the stellate ganglion (SG) in the setting of heart failure (HF). A large proportion of SG neurons function as interneurons whose networking capabilities are largely unknown. Current therapies are limited to targeting sympathetic activity at the cardiac level or surgical interventions such as stellectomy, to treat HF. Future therapies that target the SG will require understanding of their networking capabilities to modify any pathological remodeling. We observe SG networking by examining cofluctuation and specificity of SG networked activity to cardiac cycle phases. We investigate network processing of cardiopulmonary transduction by SG neuronal populations in porcine with chronic pacing-induced HF and control subjects during extended in-vivo extracellular microelectrode recordings. We find that information processing and cardiac control in chronic HF by the SG, relative to controls, exhibits: (i) more frequent, short-lived, high magnitude cofluctuations, (ii) greater variation in neural specificity to cardiac cycles, and (iii) neural network activity and cardiac control linkage that depends on disease state and cofluctuation magnitude.

Morbidity and Mortality associated with Blood Transfusions in Elective Adult Cardiac Surgery

OBJECTIVES

Perioperative transfusion thresholds have garnered increasing scrutiny as restrictive strategies have been shown to be noninferior. The study authors used data from a statewide academic collaborative to test the association between transfusion and 30-day mortality.

DESIGN

All adult patients undergoing coronary artery bypass grafting (CABG) and/or valve surgeries between 2013 and 2019 in the authors' Academic Cardiac Surgery Consortium were examined. The relationship between the number of overall packed red blood cell (pRBC) and coagulation product (CP) (fresh frozen plasma, cryoprecipitate, platelets) transfusions on 30-day mortality was evaluated. Multivariate regression was used to evaluate predictors of transfusion and study endpoints. Machine learning (ML) models also were developed to predict 30-day mortality and rank transfusion-related features by relative importance.

SETTING

At an Academic Cardiac Surgery Consortium of 5 institutions.

PARTICIPANTS

Patients ≥18 years old undergoing CABG and/or valve surgeries.

MEASUREMENTS AND MAIN RESULTS

Of the 7,762 patients (median hematocrit [HCT] 39%, IQR 35%-43%) who were included in the final study cohort, >40% were transfused at least 1 unit of pRBC or CP. In adjusted analyses, higher preoperative HCT was associated with reduced odds of mortality (adjusted odds ratio [aOR] 0.95, 95% CI 0.92-0.98), renal failure (aOR 0.95, 95% CI 0.92-0.98), and prolonged mechanical ventilation (aOR 0.97, 95% CI 0.95-0.99). In contrast, perioperative transfusions were associated with increased 30-day mortality after adjustment for preoperative HCT and other baseline features. The ML models were able to predict 30-day mortality with an area under the curve of 0.814-to-0.850, with perioperative transfusions displaying the highest feature importance.

CONCLUSIONS

The present analysis found increasing HCT to be associated with a lower incidence of mortality. The study authors also found a direct dose-response association between transfusions and all study endpoints examined.

Parsimonious machine learning models to predict resource use in cardiac surgery across a statewide collaborative

Objective

Methods

Results

Conclusions

Impact of malnutrition on outcomes following groin hernia repair: Insights from the ACS NSQIP

BACKGROUND

The present study examined the association of nutrition status, as defined by preoperative serum albumin, with postoperative outcomes and resource use after groin hernia repair.

METHODS

The 2006 to 2019 American College of Surgeons National Surgical Quality Improvement Program database was queried for adults (≥18 years) undergoing open or laparoscopic repair of inguinal or femoral hernia. Patients were stratified based on the following preoperative serum albumin levels: <2.5 g/dL (severe hypoalbuminemia), 2.5 to <3.0 (moderate hypoalbuminemia), 3.0 to <3.5 (mild), and ≥3.5 (normal albumin). Multivariable regression models were developed to assess the association of hypoalbuminemia with outcomes of interest, including 30-day mortality, postoperative complications, length of stay, and 30-day readmission.

RESULTS

Of the 261,052 patients meeting inclusion criteria, 0.3% had severe, 1.1% had moderate, and 7.4% had mild hypoalbuminemia, with 91.2% classified as normal albumin. After risk adjustment, mortality risk was greater for severe (5.8%, 95% confidence interval: 4.1-7.6), moderate (4.4%, 95% confidence interval: 3.4-5.3), and mild hypoalbuminemia (1.5%, 95% confidence interval: 1.2-1.8) relative to normal albumin (0.3%, 95% confidence interval: 0.2-0.3). Decreasing serum albumin levels were associated with a stepwise increase in risk of complications, length of stay, and 30-day readmission.

CONCLUSION

Decreased preoperative serum albumin is associated with increased mortality and morbidity after open and laparoscopic groin hernia repair. Serum albumin remains a relevant predictor of postsurgical outcomes and can thus be used in shared decision-making and optimization of malnourished patients in need of groin hernia repair.

Defining value in cardiac surgery: A contemporary analysis of cost variation across the United States

Objective

Isolated coronary artery bypass grafting and aortic valve replacement are common cardiac operations performed in the United States and serve as platforms for benchmarking. The present national study characterized hospital-level variation in costs and value for coronary artery bypass grafting and aortic valve replacement.

Methods

Adults undergoing elective, isolated coronary artery bypass grafting or aortic valve replacement were identified in the 2016-2018 Nationwide Readmissions Database. Center quality was defined by the proportion of patients without an adverse outcome (death, stroke, respiratory failure, pneumonia, sepsis, acute kidney injury, and reoperation). High-value hospitals were defined as those with observed-to-expected ratios less than 1 for costs and greater than 1 for quality, whereas the converse defined low-value centers.

Results

Of 318,194 patients meeting study criteria, 71.9% underwent isolated coronary artery bypass grafting and 28.1% underwent aortic valve replacement. Variation in hospital-level costs was evident, with median center-level cost of $36,400 (interquartile range, 29,500-46,700) for isolated coronary artery bypass grafting and $38,400 (interquartile range, 32,300-47,700) for aortic valve replacement. Observed-to-expected ratios for quality ranged from 0.2 to 10.9 for isolated coronary artery bypass grafting and 0.1 to 11.7 for isolated aortic valve replacement. Hospital factors, including volume and quality, contributed to approximately 9.9% and 11.2% of initial cost variation for isolated coronary artery bypass grafting and aortic valve replacement. High-value centers had greater cardiac surgery operative volume and were more commonly teaching hospitals compared to low-value centers, but had similar patient risk profiles.

Conclusions

Significant variation in hospital costs, quality, and value exists for 2 common cardiac operations. Center volume was associated with value and partly accounts for variation in costs. Our findings suggest the need for value-based care paradigms to reduce expenditures and optimize outcomes.

Outcomes of extracorporeal membrane oxygenation following the 2018 adult heart allocation policy

Background

The purpose of the study was to characterize changes in waitlist and post-transplant outcomes of extracorporeal membrane oxygenation (ECMO) patients bridged to heart transplantation under the 2018 adult heart allocation policy.

Methods

All adult patients listed for isolated heart transplantation from August 2016 to December 2020 were identified using the United Network for Organ Sharing database. Patients were stratified into Eras (Era 1 and Era 2) centered around the policy change on October 18, 2018. Competing risk regression was used to evaluate waitlist death or deterioration across Eras. Cox proportional hazards models were used to determine associations between use of ECMO and 1-year post-transplant mortality within each Era.

Results

Of 8,902 heart transplants included in analysis, 339 (3.8%) were bridged with ECMO (Era 2: 6.1% vs Era 1: 1.2%, P<0.001). Patients bridged with ECMO in Era 2 were less frequently female (26.0% vs 42.0%, P = 0.02) and experienced shorter waitlist times (5 vs 11 days, P<0.001) along with a lower likelihood of waitlist death or deterioration (subdistribution hazard ratio, 0.45, 95% confidence interval, CI, 0.30–0.68, P<0.001) compared to those in Era 1. Use of ECMO was associated with increased post-transplant mortality at 1-year compared to all other transplants in Era 1 (hazard ratio 3.78, 95% CI 1.88–7.61, P < 0.001) but not Era 2.

Conclusions

Patients bridged with ECMO in Era 2 experience improved waitlist and post-transplant outcomes compared to Era 1, giving credence to the increased use of ECMO under the new allocation policy.

Perioperative outcomes and readmissions following cardiac operations in kidney transplant recipients

OBJECTIVE

Although kidney transplant (KTx) recipients are at significant risk for cardiovascular disease, outcomes following cardiac operations have been examined in limited series. The present study thus aimed to assess the impact of KTx on in-hospital perioperative outcomes and readmissions in a nationally representative cohort.

METHODS

All adults undergoing elective coronary artery bypass grafting, valve repair/replacement or a combination thereof were identified from the 2010-2018 Nationwide Readmissions Database. Patients were stratified by history of KTx. Transplant-capable centres were defined as hospitals performing at least one KTx annually. To perform risk-adjustment in assessing outcomes, multivariable regression models were developed.

RESULTS

Of an estimated 1 407 351 patients included for analysis, 0.2% (n=2849) were KTx recipients. Compared with the general cardiac surgical population, patients with prior KTx experienced higher adjusted odds of in-hospital mortality (adjusted OR (AOR) 2.44, 95% CI 1.72 to 3.47, p<0.001) and perioperative complication (AOR 1.67, 95% CI 1.44 to 1.94, p<0.001). Additionally, KTx was independently associated with greater readmission rates within 30 days (AOR 1.96, 95% CI 1.65 to 2.34, p<0.001) with kidney injury contributing significantly to the burden of rehospitalisation (4.6 vs 1.8%, p=0.005). In a subpopulation comprised of only KTx recipients, treatment at a transplant-capable centre reduced odds of kidney injury with non-transplant hospitals as reference (AOR 0.65, 95% CI 0.43 to 0.98, p=0.037).

CONCLUSIONS

Kidney transplant recipients undergoing cardiac operations encounter significant risks compared with the general surgical population. Referral to transplant-capable centres should be explored to improve outcomes and to preserve allograft function in this population.

Surgeon specialty does not influence outcomes of hiatal hernia repair

BACKGROUND

Hiatal hernia repair is commonly performed by both general and thoracic surgeons. The present study examined differences in approach, setting, and outcomes by specialty for hiatal hernia repair.

METHODS

Adults undergoing hiatal hernia repair were identified in the 2012-2019 American College of Surgeons National Surgical Quality Improvement Program. Patients were grouped by specialty of the operating surgeon (thoracic surgery vs general surgery). Generalized linear models were used to evaluate the effect of specialty on mortality, major morbidity, and 30-day readmission.

RESULTS

Among 46,739 patients, 5.0% were operated on by thoracic surgery. General surgery operated on younger patients (44.7 years vs 47.0, P < .001) with lesser systemic illness (American Society of Anesthesiologists class ≥3 50.4% vs 54.8%, P < .001) compared to thoracic surgery. General surgery more commonly used laparoscopy (95.0% vs 82.6%) and less commonly used thoracic approaches than thoracic surgery (0.6% vs 8.5%, P < .001). From 2012 to 2019, the proportion of cases performed as an outpatient by general surgery increased (28.1% to 46.4%, P < .001), but it remained stable for thoracic surgery (0.1% to 0.7%, P = .10). After risk adjustment, thoracic surgery specialty was not associated with mortality (odds ratio 0.9, 95% confidence interval 0.5-1.5), major morbidity (0.9, 95% confidence interval 0.7-1.1), or readmission (0.9, 95% confidence interval 0.8-1.1). Rather, factors including surgical approach (laparotomy 1.6, 95% confidence interval 1.4-1.9; thoracoscopy/thoracotomy 2.0, 95% confidence interval 1.5-2.7), inpatient case status (2.4, 95% confidence interval 2.2-2.7), increasing ASA class, and functional status more strongly influenced major morbidity.

CONCLUSION

Operative factors, surgical approach, and patient comorbidities more strongly influence outcomes of hiatal hernia repair than does surgeon specialty, suggesting continued safety of hiatal hernia repair by both thoracic and general surgeons.

Vagus nerve stimulation using a miniaturized wirelessly powered stimulator in pigs

Neuromodulation of peripheral nerves has been clinically used for a wide range of indications. Wireless and batteryless stimulators offer important capabilities such as no need for reoperation, and extended life compared to their wired counterparts. However, there are challenging trade-offs between the device size and its operating range, which can limit their use. This study aimed to examine the functionality of newly designed wirelessly powered and controlled implants in vagus nerve stimulation for pigs. The implant used near field inductive coupling at 13.56 MHz industrial, scientific, and medical band to harvest power from an external coil. The circular implant had a diameter of 13 mm and weighed 483 mg with cuff electrodes. The efficiency of the inductive link and robustness to distance and misalignment were optimized. As a result, the specific absorption rate was orders of magnitude lower than the safety limit, and the stimulation can be performed using only 0.1 W of external power. For the first time, wireless and batteryless VNS with more than 5 cm operation range was demonstrated in pigs. A total of 84 vagus nerve stimulations (10 s each) have been performed in three adult pigs. In a quantitative comparison of the effectiveness of VNS devices, the efficiency of systems on reducing heart rate was similar in both conventional (75%) and wireless (78.5%) systems. The pulse width and frequency of the stimulation were swept on both systems, and the response for physiological markers was drawn. The results were easily reproducible, and methods used in this study can serve as a basis for future wirelessly powered implants.

Impact of Venous Thromboembolism on Readmissions and Resource Use Following Emergency General Surgery

BACKGROUND

Acute deep vein thrombosis and pulmonary embolism collectively known as venous thromboembolism (VTE), are associated with increased risk of poor clinical sequelae during inpatient hospitalizations. We examined the association of VTE with mortality, readmissions, and costs among patients undergoing emergency general surgery (EGS) operations using a national cohort.

METHODS

Adult hospitalizations for EGS (laparotomy, small bowel resection, large bowel resection, appendectomy, lysis of adhesions, cholecystectomy, and repair of perforated ulcer) within two days of admission were identified in the 2016-18 Nationwide Readmissions Database. Hospitalizations were stratified based on diagnosis of VTE and others (n-VTE).

RESULTS

Of an estimated 860, 747 ;27,700;23,100;28,300 EGS patients, .87% developed VTE during the index hospitalization. Patients in the VTE group were on average older (65.5 ± 15.3 vs 54.8 ± 18.6 years, P < .001) and more commonly male (46.7 vs 39.3%, P < .001). Venous thromboembolism was independently associated with greater odds of mortality (AOR:1.7 95% CI 1.6-1.9), increased costs ( +27 700 95% CI 23 100-28 300) and greater odds of 30-day readmissions (AOR 1.3 95% CI 1.2-1.4).

DISCUSSION

Despite national efforts to reduce its incidence, VTE affects nearly 1/100 EGS patients and is associated with increased odds of mortality as well as costs, and readmissions. Tailored approaches are warranted to reduce the impact of this pernicious complication.

Association of frailty with outcomes after elective colon resection for diverticular disease

BACKGROUND

Frailty has been associated with greater postoperative morbidity and mortality but its impact has not been investigated in patients with diverticulitis undergoing elective colon resection. Therefore, the present study examined the association of frailty with perioperative outcomes following elective colectomy for diverticular disease.

METHODS

The 2017-2019 American College of Surgeons-National Surgical Quality Improvement Program data registry was queried to identify patients (aged ≥18 years) undergoing elective colon resection for diverticular disease. The 5-factor modified frailty index (mFI-5) was used to stratify patients into non-frail (mFI 0), prefrail (mFI 1), and frail (mFI ≥2) cohorts. Major adverse events, surgical site infection, and postoperative ileus as well as prolonged length of stay, nonhome discharge, and unplanned readmission were evaluated using multivariable logistic models.

RESULTS

Of the 20,966 patients, 10.0% were frail. Compared to others, frail patients were generally older (non-frail: 55 years, [46-63], prefrail: 62, [54-70], frail: 64, [57-71]) and more commonly female (non-frail: 53.1%, prefrail: 58.6, frail: 64.4, P < .001). Frail patients more frequently underwent open colectomy and stoma creation compared with others. Frailty was associated with greater adjusted odds of major adverse event (adjusted odds ratio 1.25, 95% confidence interval 1.06-1.48), surgical site infection (adjusted odds ratio 1.28, 95% confidence interval 1.06-1.54), and postoperative ileus (adjusted odds ratio 1.59, 95% confidence interval 1.27-1.98). Similarly, frailty portended greater odds of prolonged length of stay, nonhome discharge, and unplanned readmission.

CONCLUSION

Frailty as defined by the mFI-5 was associated with greater morbidity and hospital resource use. Deployment of frailty instruments may augment traditional risk calculators and improve patient selection for elective colectomy.

Venous thromboembolism in Cancer surgery: A report from the Nationwide readmissions database

Background

The present study characterized the incidence of venous thromboembolism in a contemporary cohort of surgical oncology patients and its association with index hospitalization and postdischarge outcomes.

Methods

Adults undergoing 7 major thoracic and abdominal cancer resections were identified in the 2016–2019 Nationwide Readmissions Database. Multivariable models stratified by operative subtype were developed to evaluate the association of venous thromboembolism with outcomes of interest.

Results

Of an estimated 436,368 patients, venous thromboembolism was identified in 9,811 (2.2%) patients during index hospitalization. Esophageal (4.1%) and gastric (4.1%) resections exhibited the highest rates of venous thromboembolism, whereas pulmonary resection (1.0%) the lowest. Following adjustment, cancer resection type demonstrated the strongest association with venous thromboembolism development among all factors analyzed (adjusted odds ratio: 3.13, 95% confidence interval: 2.60–3.78). Diagnosis of venous thromboembolism was associated with increased mortality (10.2%, 95% confidence interval: 9.4–11.1 vs 1.7, 95% confidence interval: 1.6–1.7) and prolonged index hospital stay (19.5 days, 95% confidence interval: 19.1–20.0 vs 7.5, 95% confidence interval: 7.4–7.5). Of patients who survived index hospitalization, venous thromboembolism occurrence was associated with increased risk of nonhome discharge (56.4%, 95% confidence interval: 54.7–58.0 vs 14.4, 95% confidence interval: 14.2–14.7) and readmission (30.0%, 95% confidence interval: 28.5–31.1 vs 16.9, 95% confidence interval: 16.7–17.1). Additionally, venous thromboembolism substantially increased index hospitalization ($40,000, 95% confidence interval: $38,000–$42,000) and readmission costs ($3,200, 95% confidence interval: $1,700–$4,700).

Conclusion

Rates of venous thromboembolism remain high in surgical oncology patients, with cancer resection type as a major predictor of venous thromboembolism incidence. Venous thromboembolism was associated with inferior clinical and financial outcomes that extended beyond discharge. These findings underscore the importance of continued vigilance and procedure-specific prophylaxis measures.