Impact of Hospital Practice and Staffing Differences on Transesophageal Echocardiography Use in Cardiac Valve or Coronary Artery Bypass Graft Surgery.

OBJECTIVES: To identify and quantify the predictors of intraoperative transesophageal echocardiography (TEE) use among the patients undergoing cardiac valve or isolated coronary artery bypass graft (CABG) surgery. DESIGN: An observational cohort study. SETTING: This study used the Centers for Medicare and Medicaid Services administrative claims dataset of the beneficiaries undergoing valve or isolated CABG surgery between 2013 to 2015. PARTICIPANTS: Adults aged ≥65 years of age undergoing cardiac valve or isolated CABG surgery. INTERVENTIONS: Generalized linear mixed-model (GLMM) analyses were used to examine the relationship between the TEE and patient characteristics, hospital factors, and staffing differences, while accounting for clustering within hospitals. The proportion of variation in TEE use attributable to patient-level characteristics was quantified using odds ratios. Hospital-level factors and staffing differences were quantified using the median odds ratios (MOR) and interval odds ratios (IOR). MEASUREMENTS AND MAIN RESULTS: Among 261,860 patients (123,702 valve procedures and 138,158 isolated CABG), the GLMM analysis demonstrated that the strongest predictor for intraoperative TEE use was the hospital where the surgery occurred (MOR for TEE of 2.57 in valve and 4.16 in isolated CABG). The TEE staffing variable reduced the previously unexplained across-hospital variability by 9% in valve and 21% in isolated CABG, and hospitals with anesthesiologist TEE staffing (versus mixed) were more likely to use TEE in both valve and CABG (MOR for TEE of 1.21 in valve and 1.84 in isolated CABG). CONCLUSION: Hospital practice was the strongest predictor for TEE use overall. In isolated CABG surgery, hospitals with anesthesiologist TEE staffing were a primary predictor for TEE use.

Application of machine learning approaches to administrative claims data to predict clinical outcomes in medical and surgical patient populations.

OBJECTIVE: This study aimed to develop and validate a claims-based, machine learning algorithm to predict clinical outcomes across both medical and surgical patient populations. METHODS: This retrospective, observational cohort study, used a random 5% sample of 770,777 fee-for-service Medicare beneficiaries with an inpatient hospitalization between 2009-2011. The machine learning algorithms tested included: support vector machine, random forest, multilayer perceptron, extreme gradient boosted tree, and logistic regression. The extreme gradient boosted tree algorithm outperformed the alternatives and was the machine learning method used for the final risk model. Primary outcome was 30-day mortality. Secondary outcomes were: rehospitalization, and any of 23 adverse clinical events occurring within 30 days of the index admission date. RESULTS: The machine learning algorithm performance was evaluated by both the area under the receiver operating curve (AUROC) and Brier Score. The risk model demonstrated high performance for prediction of: 30-day mortality (AUROC = 0.88; Brier Score = 0.06), and 17 of the 23 adverse events (AUROC range: 0.80-0.86; Brier Score range: 0.01-0.05). The risk model demonstrated moderate performance for prediction of: rehospitalization within 30 days (AUROC = 0.73; Brier Score: = 0.07) and six of the 23 adverse events (AUROC range: 0.74-0.79; Brier Score range: 0.01-0.02). The machine learning risk model performed comparably on a second, independent validation dataset, confirming that the risk model was not overfit. CONCLUSIONS AND RELEVANCE: We have developed and validated a robust, claims-based, machine learning risk model that is applicable to both medical and surgical patient populations and demonstrates comparable predictive accuracy to existing risk models.

Association between Transesophageal Echocardiography and Clinical Outcomes after Coronary Artery Bypass Graft Surgery.

BACKGROUND: Coronary artery bypass graft (CABG) surgery is the most widely performed cardiac surgery in the United States. Transesophageal echocardiography (TEE) is frequently used in a variety of cardiac surgical procedures, but its clinical benefit in isolated CABG surgery is unclear, and guidelines remain indeterminate. The aim of this study was to compare clinical outcomes among patients undergoing isolated CABG surgery with versus without TEE in order to test the hypothesis that TEE would be associated with improved clinical outcomes after CABG surgery. METHODS: A matched retrospective cohort study was conducted among Medicare beneficiaries undergoing isolated CABG surgery with versus without intraoperative monitoring using TEE in the United States. The primary analysis was a near/far instrumental variable match that paired hospitals with similar characteristics and patient populations but with opposing probabilities for using TEE in CABG surgery. Outcomes included 30-day mortality, a composite outcome of stroke or 30-day mortality, length of hospitalization, and incidence of esophageal perforation. RESULTS: Of 114,871 patients undergoing isolated CABG surgery, 65,471 (57%) underwent TEE and 49,400 (43%) did not. Hospital-level instrumental variable matched analysis demonstrated that among the subset of 968 matched hospitals, TEE receipt was associated with lower 30-day mortality (3.7% vs 4.9%, P < .001), a lower incidence of the composite outcome of stroke or 30-day mortality (4.5% vs 5.6%, P < .001), no difference in length of hospitalization (10.32 vs 10.52 days, P = .26), and no difference in the incidence of esophageal perforation (0.01% vs 0.01%, P = .63). These results were replicated in surgeon-level and patient-level matched-pair instrumental variable analyses, and all analyses were robust to sensitivity analyses that tested for biases introduced by unmeasured confounding. CONCLUSIONS: The findings from this study suggest that TEE may offer a clinical benefit to cardiac surgical patients undergoing isolated CABG surgery.

Transesophageal Echocardiography, Mortality, and Length of Hospitalization after Cardiac Valve Surgery.

BACKGROUND: Despite recommendations regarding the use of intraoperative transesophageal echocardiography (TEE), there is no randomized evidence to support its use in cardiac valve surgery. The purpose of this study was to compare the clinical outcomes of patients undergoing open cardiac valve repair or replacement surgery with and without transesophageal echocardiographic monitoring. The hypothesis was that transesophageal echocardiographic monitoring would be associated with lower 30-day mortality and shorter length of hospitalization. METHODS: In this observational retrospective cohort study, Medicare claims were used to test the association between perioperative TEE and 30-day all-cause mortality and length of hospitalization among patients undergoing open cardiac valve repair or replacement surgery between January 1, 2010, and October 1, 2015. Baseline characteristics were defined by inpatient and outpatient claims. Medicare death records were used to ascertain 30-day mortality. Statistical analyses included regression models and propensity score matching. RESULTS: A total of 219,238 patients underwent open cardiac valve surgery, of whom 85% underwent TEE. Patients who underwent TEE were significantly older and had greater comorbidities. After adjusting for patient demographics, clinical comorbidities, surgical characteristics, and hospital factors, including annual surgical volume, the TEE group had a lower adjusted odds of 30-day mortality (odds ratio, 0.77; 95% CI, 0.73 to 0.82; P < .001), with no difference in length of hospitalization (<0.01%; 95% CI, -0.61% to 0.62%; P = .99). Results were similar across all analyses, including a propensity score-matched cohort. CONCLUSIONS: Transesophageal echocardiographic monitoring in cardiac valve repair or replacement surgery was associated with lower 30-day risk-adjusted mortality, without a significant increase in length of hospitalization. These findings support the use of TEE as routine practice in open cardiac valve repair or replacement surgery.