Adult Cardiac Surgery Database Research Articles

Operating Room Extubation for Patients Undergoing Cardiac Surgery: A National STS Database Analysis

The utility of operating room extubation (ORE) following cardiac surgery over fast-track extubation within six hours (FTE) remains contested. We hypothesized ORE would be associated with equivalent rates of morbidity and mortality, relative to FTE. Patients undergoing non-emergent cardiac surgery were identified in the Society of Thoracic Surgeons Adult Cardiac Surgery Database between July 2017 and December 2022. Only procedures with STS risk models were included. Risk-adjusted outcomes of ORE and FTE were compared via observed-to-expected ratios with 95% confidence intervals [O/E (95%CI)] aggregated over all procedure types, and ORE versus FTE adjusted odds ratio [AOR(95%CI)] specific to each procedure type using multivariable logistic regression. Analyzed outcomes were operative mortality, prolonged LOS, composite reoperation for bleeding and reintubation, and composite morbidity and mortality. The study population of 669,099 patients across 1,069 hospitals included 36,298 ORE patients in 296 hospitals. Risk-adjusted analyses found that ORE was associated with statistically similar or better results across each of the four outcomes and procedure sub-types. Notably, rates of postoperative mortality were significantly lower in ORE patients undergoing CABG (OR: 0.54 (95% CI:0.46-0.65)), AVR (OR:0.43 (95% CI:0.24-0.77)), and MVR (OR 0.48 (95% CI:0.26-0.89)). Extubation in the OR was shown to be safe and effective in a selected patient population and may be associated with superior outcomes in coronary artery bypass, aortic valve replacement and mitral valve repair. These national data appear to confirm institutional experiences regarding the potential benefit of OR extubation. Further refinement of optimal populations may justify randomized investigation.

Atrial Fibrillation After Coronary Artery Bypass Grafting and Its Relationship with Hospital Complications in São Paulo State.

Atrial fibrillation is the main complication in the postoperative period of cardiovascular surgery. Its genesis is multifactorial, so its rapid identification to mitigate the associated risks is essential. To evaluate the incidence of atrial fibrillation in patients undergoing coronary artery bypass grafting (CABG) and its relationship with other complications in our setting. This is a multicenter, observational study involving patients undergoing isolated CABG between 2017 and 2019 with data from the Registro Paulista de Cirurgia Cardiovascular (or REPLICCAR II). Variables were prospectively collected in REDCap following the definitions given by version 2.73 of the Society of Thoracic Surgeons Adult Cardiac Surgery Database. Data were collected with prior authorization from the local ethics committee and analyses performed in R software. A total of 3,803 patients were included, of these 605 had postoperative atrial fibrillation (POAF). In order to adjust the groups, propensity score matching was used. Such analyses resulted in 605 patients in each group (without POAF vs. with POAF). Among patients with POAF, the mean age was 67.56 years, with a prevalence of males (73.6%, 445 patients). Patients belonging to the group with POAF had a mortality rate of 9.26% (P=0.007), longer ventilation time (P<0.001), pneumonia (P<0.001), and sepsis (P<0.001). In multiple analysis, acute renal dysfunction (P=0.032) and longer intensive care unit stay (P<0,001) were associated with the presence of POAF. POAF in CABG is associated with longer intensive care unit and hospital stay, as well as renal dysfunction, pneumonia, and in-hospital mortality.

Outcomes of Isolated Tricuspid Valve Surgery: A Society of Thoracic Surgeons Analysis and Risk Model

BackgroundTo provide patients and surgeons with clinically relevant information, The Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database was queried to develop a risk model for isolated tricuspid valve (TV) operations. MethodsAll patients in the STS Adult Cardiac Surgery Database who had undergone isolated TV repair or replacement (N = 13,587; age 48.3 ± 18.4 years) were identified (July 2017 to June 2023). Multivariable logistic regression accounting for TV replacement vs repair was used to model 8 operative outcomes: mortality, morbidity or mortality or both, stroke, renal failure, reoperation, prolonged ventilation, short hospital stay, and prolonged hospital stay. Model discrimination (C-statistic) and calibration were assessed using 9-fold cross-validation. ResultsThe isolated TV study population included 41.1% repairs (N = 5,583; age 52.6 ± 18.1 years) and 58.9% replacements (N = 8,004; age 45.3 ± 18.0 years). The overall predicted risk of operative mortality was 5.6%, and it was similar in TV repairs and replacements (5.5% and 5.7%, respectively), as was the predicted risk of composite morbidity and mortality (28.2% and 26.8%). TV replacements were generally performed in younger patients with a higher endocarditis prevalence than TV repairs (45.7% vs 21.1%). The model yielded a C-statistic of 0.81 for mortality and 0.76 for the composite of morbidity and mortality, with excellent observed-to-expected calibration that was comparable in all subcohorts and predicted risk decile groups. ConclusionsAn STS risk model has been developed for isolated TV surgery. The current mortality of isolated TV operations is lower than previously observed. This risk prediction model and these contemporary outcomes provide a new benchmark for current and future isolated TV interventions.

Trends in the Management of Anterior Mitral Leaflet Regurgitation

The overall prevalence of mitral valve replacement (MVR) or MV repair at the time of cardiac surgery in the setting of isolated anterior mitral leaflet degenerative pathologic status in the US population is unknown. To investigate the prevalence of MVR and MV repair using the Society of Thoracic Surgeons' Adult Cardiac Surgery Database. In a cross-sectional study, all patients diagnosed with isolated anterior mitral leaflet degenerative regurgitation who underwent either surgical MVR or MV repair between July 1, 2011, and June 30, 2022, were identified. Linear regression analysis was used to assess trends over time. Assessment of the trends in MV repair and MVR over time. A total of 16 259 patients (9624 [59.2%] men) were identified, and the median age was 68 (IQR, 58-74) years. A total of 7214 patients (44.4%) had MVR, and 9045 (55.6%) had MV repair. There was a declining trend of MV repair from 58.0% in 2011 to 51.6% in 2022 (P = .05). The MVR group was older (median [IQR] age, 70 [62-77] vs 67 [58-74] years; P < .001) and had more comorbidities. A total of 85.1% of all patients underwent concomitant procedures. In 81.7% of MVR cases, no attempt at MV repair was made. The median (IQR) annual hospital volume was lower with MVR vs MV repair (2.50 [1.50-5.00] vs 4.00 [2.00-7.00]; P < .001). Conventional surgical approaches were most common (91.5%) but with a declining trend (P < .001). Minimally invasive approaches were used in 13.1% (robotic, 4.6%), and with an inclining trend from 5.0% in 2011 to 12.0% in 2022 (P < .001). Annuloplasty was performed in 88.8% of MV repair cases. Its use as a sole mean of MV repair decreased from 48.0% in 2011 to 13.9% in 2022 (P < .001). Repair maneuvers in addition to annuloplasty were neochordae (overall 40.1%, increasing from 22.5% in 2011 to 62.3% in 2022; P < .001), leaflet resection (overall 10.2%, decreasing from 13.1% in 2011 to 7.9% in 2022, P = .002), edge-to-edge MV repair (overall 5.3%, decreasing from 6.9% in 2011 to 4.5% in 2022; P = 0.04), and chordal transfer (overall 2.4%, decreasing from 2.7% in 2011 to 0.7% in 2022; P = .004). In this cross-sectional study, MV repair was the preferred option for degenerative mitral valve disease but was only slightly more commonly performed than MVR for isolated anterior leaflet pathologic status. A large proportion of MVR was performed without an MV repair attempt, suggesting reluctance to repair this pathologic condition.

Cardiac Surgery After Transcatheter Aortic Valve Replacement: Trends and Outcomes

BackgroundReports of cardiac operations after transcatheter aortic valve replacement (TAVR) and early TAVR explantation are increasing. The purpose of this report is to document trends and outcomes of cardiac surgery after initial TAVR. MethodsThe Society of Thoracic Surgeons Adult Cardiac Surgery Database was queried for all adult patients undergoing cardiac surgery after a previously placed TAVR between January 2012 and March 2023. This identified an overall cohort and 2 subcohorts: nonaortic valve operations and surgical aortic valve replacement (SAVR) after previous TAVR. Cohorts were examined with descriptive statistics, trend analyses, and 30-day outcomes. ResultsOf 5457 patients who were identified, 2485 (45.5%) underwent non-SAVR cardiac surgery, and 2972 (54.5%) underwent SAVR. The frequency of cardiac surgery after TAVR increased 4235.3% overall and 144.6% per year throughout the study period. The incidence of operative mortality and stroke were 15.5% and 4.5%, respectively. Existing The Society of Thoracic Surgeons risk models performed poorly, because observed-to-expected mortality ratios were significantly >1.0. Among those undergoing SAVR after TAVR, increasing preoperative surgical urgency, age, dialysis, need for SAVR, and concomitant procedures were associated with increased mortality, whereas type of TAVR explant was not. ConclusionsThe need for cardiac surgery, including redo SAVR after TAVR, is increasing rapidly. Risks are higher, and outcomes are worse than predicted. These data should closely inform heart team decisions if TAVR is considered at lowering age and risk profiles in the absence of longitudinal evidence.

Comparison of Transcatheter Edge-to-Edge Mitral Valve Repair for Primary Mitral Regurgitation Outcomes to Hospital Volumes of Surgical Mitral Valve Repair.

Transcatheter edge-to-edge mitral valve (MV) repair (TEER) is an effective treatment for patients with primary mitral regurgitation at prohibitive risk for surgical MV repair (MVr). High-volume MVr centers and high-volume TEER centers have better outcomes than low-volume centers, respectively. However, whether MVr volume predicts TEER outcomes remains unknown. We hypothesized that high-volume MV surgical centers would have superior risk-adjusted outcomes for TEER than low-volume centers. We combined data from the American College of Cardiology/Society of Thoracic Surgeons Transcatheter Valve Therapy registry and the Society of Thoracic Surgeons adult cardiac surgery database. MVr was defined as leaflet resection or artificial chords with or without annuloplasty and was evaluated as a continuous variable and as predefined categories (<25, 25-49, and ≥50 MV repairs/year). A generalized linear mixed model was used to evaluate risk-adjusted in-hospital/30-day mortality, 30-day heart failure readmission, and TEER success (mitral regurgitation ≤2+ and gradient <5 mm Hg). The study comprised 41 834 patients from 500 sites of which 332 (66.4%) were low, 102 (20.4%) intermediate, and 66 (13.2%) high-volume surgical centers (P<0.001). TEER success was 54.6% and was not statistically significantly different across MV surgical site volumes (P=0.4271). TEER mortality at 30 days was 3.5% with no significant difference across MVr volume on unadjusted (P=0.141) or adjusted (P=0.071) analysis of volume as a continuous variable. One-year mortality was 15.0% and was lower for higher MVr volume centers when adjusted for clinical and demographic variables (P=0.027). Heart failure readmission at 1 year was 9.4% and was statistically significantly lower in high-volume centers on both unadjusted (P=0.017) or adjusted (P=0.015) analysis. TEER can be safely performed in centers with low volumes of MV repair. However, 1-year mortality and heart failure readmission are superior at centers with higher MVr volume.

Multiarterial vs Single-Arterial Coronary Surgery: 10-Year Follow-up of 1 Million Patients

BackgroundAlthough many options exist for multivessel coronary revascularization, controversy persists over whether multiarterial grafting (MAG) confers a survival advantage over single-arterial grafting (SAG) with saphenous vein in coronary artery bypass grafting (CABG). This study sought to compare longitudinal survival between patients undergoing MAG and those undergoing SAG. MethodsAll patients undergoing isolated CABG with ≥2 bypass grafts in The Society of Thoracic Surgeons Adult Cardiac Surgery Database (2008-2019) were linked to the National Death Index. Risk adjustment was performed using inverse probability weighting and multivariable modeling. The primary end point was longitudinal survival. Subpopulation analyses were performed and volume thresholds were analyzed to determine optimal benefit. ResultsA total of 1,021,632 patients underwent isolated CABG at 1108 programs (100,419 MAG [9.83%]; 920,943 SAG [90.17%]). Median follow-up was 5.30 years (range, 0-12 years). After risk adjustment, all characteristics were well balanced. At 10 years, MAG was associated with improved unadjusted (hazard ratio, 0.59; 95% CI 0.58-0.61) and adjusted (hazard ratio, 0.86; 95% CI, 0.85-0.88) 10-year survival. Center volume of ≥10 MAG cases/year was associated with benefit. MAG was associated with an overall survival advantage over SAG in all subgroups, including stable coronary disease, acute coronary syndrome, and acute infarction. Survival was equivalent to that with SAG for patients age ≥80 years and those with severe heart failure, renal failure, peripheral vascular disease, or obesity. Only patients with a body mass index ≥40 kg/m2 had superior survival with SAG. ConclusionsMultiarterial CABG is associated with superior long-term survival and should be the surgical multivessel revascularization strategy of choice for patients with a body mass index of less than 40 kg/m2.

Red Blood Cell Transfusion and Pulmonary Complications: The Society of Thoracic Surgeons Adult Cardiac Surgery Database Analysis

BackgroundIntraoperative packed red blood cell (PRBC) transfusion during cardiac surgery is associated with increased postoperative morbidity and mortality; however, data on the association between PRBC transfusion and postoperative pulmonary complications (PPCs) are somewhat conflicting. Using The Society of Thoracic Surgeons Adult Cardiac Surgery Database, we sought to determine whether intraoperative PRBC transfusion was associated with PPCs as well as with longer intensive care unit (ICU) stay after isolated coronary artery bypass grafting (CABG) surgery. MethodsA registry-based cohort study was performed on 751,893 patients with isolated CABG between January 1, 2015, to December 31, 2019. Using propensity score–weighted regression analysis, we analyzed the effect of intraoperative PRBC on the incidence of PPCs (hospital-acquired pneumonia [HAP], mechanical ventilation for >24 hours, or reintubation), ICU length of stay, and ICU readmission. ResultsTransfusion of 1, 2, 3, and ≥4 units of PRBCs was associated with increased odds for HAP (odds ratios [ORs], 1.24 [95% CI, 1.21-1.26], 1.28 [95% CI, 1.26-1.32], 1.36 [95% CI, 1.33-1.39], 1.31 [95% CI, 1.28-1.34]), reintubation (ORs, 1.23 [95% CI, 1.21-1.25], 1.38 [95% CI, 1.35-1.40], 1.57 [95% CI, 1.55-1.60], 1.70 [95% CI, 1.67-1.73]), prolonged ventilation (ORs, 1.34 [95% CI, 1.33-1.36], 1.56 [95% CI, 1.53-1.58], 1.97 [95% CI, 1.94-2.00], 2.27 [95% CI, 2.24-2.30]), initial ICU length of stay (mean difference in hours, 6.79 [95% CI, 6.00-7.58], 9.55 [95% CI, 8.71-10.38], 17.26 [95% CI, 16.38-18.15], 22.14 [95% CI, 21.22-23.06]), readmission to ICU (ORs, 1.14 [95% CI, 1.12-1.64], 1.15 [95% CI, 1.12-1.17], 1.15 [95% CI, 1.13-1.18], 1.32 [95% CI, 1.29-1.35]), and additional ICU length of stay (mean difference in hours, 0.55 [95% CI, 0.18-0.92], 0.38 [95% CI, 0.00-0.77], 1.02 [95% CI, 0.61-1.43], 1.83 [95% CI, 1.40-2.26]), respectively. ConclusionsIntraoperative PRBC transfusion was associated with increased incidence of PPCs, prolonged ICU stay, and ICU readmissions after isolated CABG surgery.

The Society of Thoracic Surgeons Adult Cardiac Surgery Database: Intraoperative Echocardiography Reporting

To identify trends in the reporting of intraoperative transesophageal echocardiographic (TEE) data in the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database (ACSD) and the Adult Cardiac Anesthesiology (ACA) module by period, practice type, and geographic distribution, and to elucidate ongoing areas for practice improvement. A retrospective study. STS ACSD. Procedures reported in the STS ACSD between July 2017 and December 2021 in participating programs in the United States. None MEASUREMENTS AND MAIN RESULTS: Intraoperative TEE is reported for 73% of all procedures in ACSD. Although the intraoperative TEE data reporting rate increased from 2017 to 2021 for isolated coronary artery bypass graft surgery, it remained low at 62.2%. The reporting of relevant echocardiographic variables across a wide range of procedures has steadily increased over the study period but also remained low. The reporting in the ACA module is high for most variables and across all anesthesia care models; however, the overall contribution of the ACA module to the ACSD remains low. This progress report suggests a continued need to raise awareness regarding current practices of reporting intraoperative TEE in the ACSD and the ACA, and highlights opportunities for improving reporting and data abstraction.

Renal recovery in cardiac surgery patients requiring postoperative renal-replacement therapy

ObjectiveRenal failure after cardiac surgery is associated with increased morbidity and mortality. There is a lack of data examining the rate of renal recovery after patients have started dialysis following cardiac surgery. We aimed to determine the frequency of and time to renal recovery of patients requiring dialysis after cardiac surgery. MethodsAll patients who developed new-onset renal failure requiring dialysis following cardiac surgery at our institution from 2011 to 2022 were included. Renal recovery, time to renal recovery, and mortality at 1 year were merged with patients’ Society of Thoracic Surgeons Adult Cardiac Surgery Database files. Kaplan–Meier analysis was used to predict time to renal recovery; we censored patients who died or were lost to follow up. Cox regression was used for risk-adjustment. ResultsA total of 312 patients were included in the final analysis. Mortality during index hospital admission was 33% (n = 105), and mortality at 1 year was 45% (n = 141). Of those surviving at 1 year, 69% (n = 118) remained renally recovered. Median renal recovery time was 56 (37-74) days. Accounting for mortality as a competing risk, 51% of patients were predicted to achieve renal recovery. Increasing age (hazard ratio, 0.98; 0.514-0.94, P < .026) and increasing total packed red blood cells (hazard ratio, 0.0958; 0.937-0.987, P < .001) received were found to be significant negative predictors of renal recovery in the Fine-Gray model for subhazard distribution. ConclusionsMore than two-thirds of patients with renal failure who survived the perioperative period had renal recovery within 1 year after surgery. Recovery was driven primarily by postoperative complications rather than comorbidities and intraoperative factors, suggesting renal failure in the postoperative cardiac surgery patient surviving to discharge is unlikely to be permanent.

The Society of Thoracic Surgeons Adult Cardiac Surgery Database: 2023 Update on Procedure Data and Research

The Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database is one of the largest and most comprehensive contemporary clinical databases in use. It now contains >9 million procedures from 1010 participants and 3651 active surgeons. Using audited data collection, it has provided the foundation for multiple risk models, performance metrics, health policy decisions, and a trove of research studies to improve the care of patients in need of cardiac surgical procedures. This annual report provides an update on the current status of the database and summarizes the development of new risk models and the STS Online Risk Calculator. Further, it provides insights into current practice patterns, such as the change in the demographics among patients undergoing aortic valve replacement, the use of minimally invasive techniques for valve and bypass surgery, or the adoption of surgical ablation and left atrial appendage ligation among patients with atrial fibrillation. Lastly, an overview of the research conducted using the STS Adult Cardiac Surgery Database and future directions for the database are provided.

Abstract 15146: Superior Outcomes of Dual-Arterial Compared With Single-Arterial CABG Are Maintained in Low-Volume Centers in the Veterans Health Administration

Introduction: A 2023 report of the STS Adult Cardiac Surgery Database (ACSD) demonstrated worse clinical outcomes with dual arterial CABG (DAG) compared to single arterial CABG (SAG) at low DAG volume centers (&lt;30 DAG/year). It is unclear how generalizable these results are to low DAG volume centers in the Veterans Health Administration (VHA). Objective: We investigated outcomes of DAG with bilateral internal thoracic artery (BITA) or radial artery (RA) plus vein grafts (VG) compared to SAG using a left internal thoracic artery (LITA) graft plus VG in the VHA. Methods: This study analyzed data from 25,969 patients undergoing isolated CABG between 2005 and 2015 at 44 VHA hospitals (all performing&lt;30 DAG/year). The primary outcome was 5-year mortality, and the secondary outcome was a composite of major adverse cardiac and cerebrovascular events (MACCE; all deaths, myocardial infarction, stroke, or repeat revascularization). Results: 1,261 patients (4.9%) received DAG (66.8% LITA plus RA/VG and 33.2% BITA/VG) and 24,708 patients (95.1%) had SAG. Median age and grafts per patient for DAG and SAG were 62 and 63 years and 3.0 and 3.0 grafts, respectively. At 5 years, mortality rates for DAG (10.6% [134 events]) were significantly lower vs. SAG (16.2% [4,011 events]). Similarly, MACCE were lower for DAG (22.0% [278 events]) vs. SAG (28.6% [7,078 events]). Kaplan-Meier analysis for all deaths showed a hazard ratio (HR) of 0.64 (95% CI: 0.54 to 0.76) favoring DAG (Figure). A covariate-adjusted Cox model for DAG vs SAG revealed adjusted HR of 0.70 (95% CI: 0.58 to 0.85) for all-cause mortality and 0.80 (95% CI: 0.70 to 0.91) for MACCE. Conclusions: In contrast to a recent STS-ACSD analysis, DAG in the VHA was associated with significantly improved 5-year survival and rates of MACCE compared to SAG. Additional studies are needed to understand the observed lack of negative DAG low-volume/outcome relationship in the VHA.

Abstract 12145: Intraoperative Anemia Mediates Sex Disparity in Operative Mortality After Coronary Artery Bypass Grafting

Introduction: Women undergoing coronary artery bypass grafting (CABG) have higher mortality compared with men, yet its drivers are unclear. Hypothesis: The association of female sex with the risk of operative mortality after CABG may be mediated by intraoperative anemia. Aim: To investigate the relationship between sex, intraoperative anemia, and operative mortality. Methods: Retrospective cohort study of 1,434,225 isolated primary CABG patients (344,357 women) from the Adult Cardiac Surgery Database of the Society of Thoracic Surgeons (2011-2022). The primary outcome was operative mortality. The attributable risk (AR, quantifying the risk-adjusted strength of the association of female sex with CABG outcomes) was calculated. Causal mediation analysis adjusted for 42 baseline risk factors was used to derive the total effect of female sex on mortality risk and the proportion of that effect mediated by intraoperative anemia (nadir hematocrit). Spline regression evaluated the relationship of operative mortality and nadir intraoperative hematocrit. Results: Women had lower median preoperative hematocrit (36.9%, interquartile range [IQR] 33.3-40.0 vs 41.0% [37.4-44.0], standardized mean difference [SMD] 74.0%) and nadir intraoperative hematocrit (22.0% [20.0-25.0] vs 27.0% [24.0-30.0], SMD 97.0%) compared with men. Women had higher operative mortality than men (2.8% vs 1.7%, p&lt;0.001, adjusted odds ratio 1.36, 95% confidence interval [CI] 1.30-1.41). The AR of female sex for operative mortality was 1.21 (95% CI 1.17-1.24). After adjusting for nadir intraoperative hematocrit, the AR was reduced by 43% (1.12, 95% CI 1.09-1.16). Intraoperative anemia mediated 38.5% of the increased mortality risk associated with female sex (95% CI 32.3-44.7%). Spline regression showed a stronger association between operative mortality and nadir intraoperative hematocrit at hematocrit values below 22.0% (p&lt;0.001). Conclusions: The association of female sex with increased CABG operative mortality is mediated to a large extent by intraoperative anemia. Avoiding nadir intraoperative hematocrit values below 22.0% may reduce sex differences in CABG operative mortality.

Interpretable Machine Learning-Based Predictive Modeling of Patient Outcomes Following Cardiac Surgery

ObjectiveThe clinical applicability of machine learning predictions of patient outcomes following cardiac surgery remains unclear. We applied machine learning to predict patient outcomes associated with high morbidity and mortality after cardiac surgery and identified the importance of variables to the derived model’s performance. MethodsWe applied machine learning to the Society of Thoracic Surgeons Adult Cardiac Surgery Database to predict post-operative hemorrhage requiring re-operation, venous thromboembolism and stroke. We used permutation feature importance to identify variables important to model performance and a misclassification analysis to study the limitations of the model. ResultsThe study dataset included 662,772 subjects who had cardiac surgery between 2015 and 2017 and 240 variables. Hemorrhage requiring re-operation, venous thromboembolism and stroke occurred in 2.9%, 1.2% and 2.0% of subjects respectively. The model performed remarkably well at predicting all three complications (AUC 0.92-0.97). Pre- and intra-operative variables were not important to model performance. Instead, performance for the prediction of all three outcomes was driven primarily by several post-operative variables, including known risk factors for the complications such as mechanical ventilation and new-onset of post-operative arrhythmias. Many of the post-operative variables important to model performance also increased the risk of subject misclassification, indicating internal validity. ConclusionsA machine learning model accurately and reliably predicts patient outcomes following cardiac surgery. Post-operative, as opposed to pre- or intra-operative variables, are important to model performance. Interventions targeting this period including minimizing the duration of mechanical ventilation and early treatment of new-onset post-operative arrhythmias may help lower the risk of these complications.

Safety-Net Hospital Status Is Associated With Coronary Artery Bypass Grafting Outcomes at an Urban Academic Medical Center

IntroductionSocioeconomic disparities impact outcomes after cardiac surgery. At our institution, cardiac surgery cases from the safety-net, county funded hospital (CH), which primarily provides care for underserved patients, are performed at the affiliated university hospital. We aimed to investigate the association of socioeconomic factors and CH referral status with outcomes after coronary artery bypass grafting (CABG). MethodsThe institutional Adult Cardiac Surgery database was queried for perioperative and demographic data from patients who underwent isolated CABG between January 2014 and June 2020. The primary outcome was major adverse cardiovascular event (MACE), a composite of postoperative myocardial infarction, stroke, or death. Secondary outcomes included individual complications. Chi-square, Wilcoxon rank-sum, and logistic regression analyses were used to compare differences between CH and non-CH cohorts. ResultsWe included 836 patients with 472 (56.5%) from CH. Compared to the non-CH cohort, CH patients were younger, more likely to be Hispanic, non-English speaking, and be completely uninsured or require state-specific financial assistance. CH patients were more likely to have a history of tobacco and drug use, liver disease, diabetes, prior myocardial infarction, and greater degrees of left main coronary and left anterior descending artery stenosis. CH cases were less likely to be elective. The incidence of MACE was significantly higher in the CH cohort (16.3% versus 8.2%, P = 0.001). There were no significant differences in 30-d mortality, home discharge, prolonged mechanical ventilation, bleeding, sepsis, pneumonia, new dialysis requirement, cardiac arrest, or multiorgan system failure between cohorts. CH patients were more likely to develop renal failure and less likely to develop atrial fibrillation. On multivariable analysis, CH status (odds ratio 2.39, 95% confidence interval 1.25-4.55, P = 0.008) was independently associated with MACE. ConclusionsCH patients undergoing CABG presented with greater comorbidity burden, more frequently required nonelective surgery, and are at significantly higher risk of postoperative MACE.

Effect of elevated HbA1c on outcomes in on-pump versus off-pump coronary artery bypass grafting

BackgroundDiabetic patients are at an increased risk of cardiovascular morbidities. We aimed to examine if elevated pre-operative glycosylated hemoglobin (HbA1c) levels are associated with higher likelihood of experiencing adverse events in on-pump (ONCAB) versus off-pump (OPCAB) coronary artery bypass graft (CABG) procedures. We examined characteristics of patients undergoing CABG using our institutional STS Adult Cardiac Surgery Database (ACSD) from 2014 to 2020. Descriptive statistics and univariate analyses were used to compare postoperative outcomes between ONCAB and OPCAB based on preoperative HbA1c levels: (1) HbA1c ≤ 6.0%, (2) 6.0% < HbA1c ≤ 7.0%, (3) 7.0% < HbA1c ≤ 8.5%, (4) HbA1c > 8.5%. Multivariable models were built to assess risk factors associated with adverse events. Primary outcomes were operative mortality and stroke.ResultsFor ONCAB, statistically significant associations were found between increasing HbA1c and new post-operative dialysis (p=0.01), rates of readmission (p=0.003) and greater lengths of stay (p=0.002). For OPCAB, statistically significant associations were found between increasing HbA1c and rates of operative mortality (p=0.04), post-operative renal failure (p=0.0001), new post-operative dialysis (p=0.0001), sternal wound infection (p=0.01), and greater lengths of stay (p=0.03). No significant relationship was noted between HbA1c and stroke, reoperation due to bleeding, or post-operative transfusion.ConclusionsIncreasing HbA1c positively correlated with numerous adverse patient outcomes in both ONCAB and OPCAB, and differences were noted in which outcomes were most impacted between the two techniques. Pre-operative medical optimization from a diabetes standpoint is paramount to improve CABG outcomes in both on-pump or off-pump techniques.

Practice makes perfect? Institutional coronary artery bypass case volumes and outcomes.

Older studies of coronary artery bypass grafting (CABG) institutional case volumes and outcomes reported conflicting results. We explored this association in the rapidly changing contemporary practice of American surgeons using the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database. The 2018-2019 isolated primary CABG experience in the STS Adult Cardiac Surgery Database was analysed (241902 patients; 1014 hospitals; 2718 surgeons). Generalized Estimating Equations were used to estimate coefficients between CABG institutional case volumes and outcomes. The observed-to-expected ratios based on STS risk models were used to assess risk-adjusted operative mortality (OM), mortality/major morbidity (MM) and deep sternal wound infections (DSWI) as a function of institutional case volumes. The mean (standard deviation) OM, MM and DSWI rates were 2.1% (2.7), 11.1% (9.2) and 0.6% (0.5), respectively. The mean (standard deviation) institutional case volumes per study period was 239 (192); 23% and 9% of institutions performed <100 and >500 cases/study period, respectively. There was a weak negative correlation between expected mortality (R2 -0.0014), OM (R2 -0.0272), MM (R2 -0.1213) and DSWI (R2 -0.003) and institutional case volumes. CABG outcomes generally improve with increasing institutional case volumes. Given the large number of CABG cases performed nationally, even the documented weak correlation has the potential to appreciably decrease OM, MM and DSWI if cases are performed at higher volume institutions. Studies focusing on additional hospital and surgeon factors are warranted to further define quality improvement opportunities.

Association Between Functional Tricuspid Regurgitation and Mortality Following Cardiac Surgery

BackgroundCurrent guidelines recommend concomitant repair of certain non-severe cases of tricuspid regurgitation (TR) in patients undergoing cardiac surgery, but the prognostic relevance and postsurgical impact of the TR remain uncertain. ObjectivesThe purpose of this study was to determine the prognostic impact of functional TR in patients undergoing diverse cardiac surgeries and to examine the effect-modifying role of patient characteristics in patients in whom TR confers a greater risk of adverse outcomes. MethodsPatients undergoing coronary artery bypass, aortic, and mitral valve surgery were included. Patients with severe TR, organic tricuspid valve pathology, undergoing tricuspid valve surgery or without a recent preoperative echocardiogram were excluded. Clinical variables were extracted from the Society of Thoracic Surgeons Adult Cardiac Surgery Database. An independent cohort was used for external validation. ResultsOf 2,119 patients (mean age 67.4 years; 29% females), TR severity was moderate in 185 (9%), mild in 636 (30%), trivial in 1,126 (53%), and absent in 172 (8%). There were 238 deaths during the median follow-up period of 2.6 years. After adjusting for relevant factors, moderate TR was found to be independently associated with mid-term mortality (HR: 2.58; 95% CI: 1.22-5.47) and with in-hospital mortality or major morbidity (OR: 3.18; 95% CI: 1.37-7.42). The association between TR and mortality was apparent when preoperative pulmonary artery systolic pressure was <40 mm Hg but not ≥40 mm Hg (P for interaction = 0.036). ConclusionsIn this diverse cohort of contemporary cardiac surgery patients, moderate functional TR was associated with increased mortality and major morbidity, particularly in the absence of pulmonary hypertension.

Interhospital variability in failure to rescue rates following aortic valve surgery

ObjectiveThis study evaluated interhospital variability and determinants of failure-to-rescue for patients undergoing surgical aortic valve replacement. MethodsAn observational study was conducted among 28,842 patients undergoing aortic valve replacement with or without coronary artery bypass grafting between July 2011 and June 2017 across 90 hospitals participating in the Society of Thoracic Surgeons Adult Cardiac Surgery Database. Postoperative complications were defined as major (stroke, renal failure, reoperation, prolonged ventilation, sternal infection) and overall (major plus 14 other morbidities). Hospital terciles of observed to expected (O/E) mortality were compared on crude rates of major and overall complications, operative mortality, and failure to rescue (among major and overall complications). The correlation between hospital observed and expected failure-to-rescue rates was assessed. ResultsMedian Society of Thoracic Surgeons Adult Cardiac Surgery Database predicted mortality risk was similar across hospital O:E mortality terciles (P = .10). As expected, mortality rates significantly increased across terciles (low O/E tercile: 1.6%, high O/E tercile: 4.7%; P < .001). Failure-to-rescue rates increased substantially across hospital mortality terciles among patients with major (low tercile, 8.8% and high tercile, 20.8%) and overall (low tercile, 3.0% and high tercile, 8.9%) complications. Hospital-level expected failure to rescue had a higher correlation with observed complications for overall complications (R2 = 0.71) compared with Society of Thoracic Surgeons major complications (R2 = 0.24). ConclusionsConsiderable interhospital variation exists in failure-to-rescue rates following aortic valve replacement. Hospitals in the low O/E mortality tercile experience failure to rescue nearly one-third less than those in the high O/E mortality tercile. Efforts to advance quality will benefit from identifying and disseminating optimal rescue strategies in this patient population.

Robotic Mitral Valve Repair for Degenerative Mitral Regurgitation

BackgroundContemporary national utilization and comparative safety data of robotic mitral valve repair for degenerative mitral regurgitation compared with nonrobotic approaches are lacking. The study aimed to characterize national trends of utilization and outcomes of robotic mitral repair of degenerative mitral regurgitation compared with sternotomy and thoracotomy approaches. MethodsPatients undergoing intended mitral repair of degenerative mitral regurgitation in The Society of Thoracic Surgeons Adult Cardiac Surgery Database between 2015 and 2021 were examined. Mitral repair was performed in 61,322 patients. Descriptive analyses characterized center-level volumes and outcomes. Propensity score matching separately identified 5540 pairs of robotic vs thoracotomy approaches and 6962 pairs of robotic vs sternotomy approaches. Outcomes were operative mortality, composite mortality and major morbidity, postoperative length of stay, and conversion to mitral replacement. ResultsThrough the 7-year study period, 116 surgeons across 103 hospitals performed mitral repair robotically. The proportion of robotic cases increased from 10.9% (949 of 8712) in 2015 to 14.6% (1274 of 8730) in 2021. In both robotic-thoracotomy and robotic-sternotomy matched pairs, mortality and morbidity were not significantly different, whereas the robotic approach had lower conversion (1.2% vs 3.1% for robotic-thoracotomy and 1.0% vs 3.7% for robotic-sternotomy), shorter length of stay, and fewer 30-day readmissions. Mortality and morbidity were lower at higher-volume centers, crossing the national mean mortality and morbidity at a cumulative robotic mitral repair case of 40. ConclusionsRobotic mitral repair is a safe and effective approach and is associated with comparable mortality and morbidity, a lower conversion rate, a shorter length of stay, and fewer 30-day readmissions than thoracotomy or sternotomy approaches.