Pragmatic Evaluation of a Deep-Learning Algorithm to Automate Ejection Fraction on Hand-Held, Point-of-Care Echocardiography in a Cardiac Surgical Operating Room.

OBJECTIVE: To test the correlation of ejection fraction (EF) estimated by a deep-learning-based, automated algorithm (Auto EF) versus an EF estimated by Simpson's method. DESIGN: A prospective observational study. SETTING: A single-center study at the Hospital of the University of Pennsylvania. PARTICIPANTS: Study participants were ≥18 years of age and scheduled to undergo valve, aortic, coronary artery bypass graft, heart, or lung transplant surgery. INTERVENTIONS: This noninterventional study involved acquiring apical 4-chamber transthoracic echocardiographic clips using the Philips hand-held ultrasound device, Lumify. MEASUREMENTS AND MAIN RESULTS: In the primary analysis of 54 clips, compared to Simpson's method for EF estimation, bias was similar for Auto EF (-10.17%) and the experienced reader-estimated EF (-9.82%), but the correlation was lower for Auto EF (r = 0.56) than the experienced reader-estimated EF (r = 0.80). In the secondary analyses, the correlation between EF estimated by Simpson's method and Auto EF increased when applied to 27 acquisitions classified as adequate (r = 0.86), but decreased when applied to 27 acquisitions classified as inadequate (r = 0.46). CONCLUSIONS: Applied to acquisitions of adequate image quality, Auto EF produced a numerical EF estimate equivalent to Simpson's method. However, when applied to acquisitions of inadequate image quality, discrepancies arose between EF estimated by Auto EF and Simpson's method. Visual EF estimates by experienced readers correlated highly with Simpson's method in both variable and inadequate imaging conditions, emphasizing its enduring clinical utility.

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

OBJECTIVES: 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. DESIGN: A retrospective study. SETTING: STS ACSD. PARTICIPANTS: Procedures reported in the STS ACSD between July 2017 and December 2021 in participating programs in the United States. INTERVENTIONS: 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. CONCLUSIONS: 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.

Bridging preference-based instrumental variable studies and cluster-randomized encouragement experiments: Study design, noncompliance, and average cluster effect ratio.

Instrumental variable (IV) methods are widely used in medical research to draw causal conclusions when the treatment and outcome are confounded by unmeasured confounding variables. One important feature of such studies is that the IV is often applied at the cluster level, for example, hospitals' or physicians' preference for a certain treatment where each hospital or physician naturally defines a cluster. This paper proposes to embed such observational IV data into a cluster-randomized encouragement experiment using nonbipartite matching. Potential outcomes and causal assumptions underpinning the design are formalized and examined. Testing procedures for two commonly used estimands, Fisher's sharp null hypothesis and the pooled effect ratio (PER), are extended to the current setting. We then introduce a novel cluster-heterogeneous proportional treatment effect model and the relevant estimand: the average cluster effect ratio. This new estimand is advantageous over the structural parameter in a constant proportional treatment effect model in that it allows treatment heterogeneity, and is advantageous over the PER estimand in that it does not suffer from Simpson's paradox. We develop an asymptotically valid randomization-based testing procedure for this new estimand based on solving a mixed-integer quadratically constrained optimization problem. The proposed design and inferential methods are applied to a study of the effect of using transesophageal echocardiography during coronary artery bypass graft surgery on patients' 30-day mortality rate. R package ivdesign implements the proposed method.

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.

Validation of Claims Data for the Identification of Intraoperative Transesophageal Echocardiography During Cardiac Surgery.

OBJECTIVE: The goal of this study was to assess the validity of Current Procedural Terminology (CPT) claims data for the identification of intraoperative transesophageal echocardiography (TEE) during cardiac surgery. DESIGN: This study was a retrospective, cohort analysis. SETTING: This study used data from electronic medical records (EMRs), in combination with CPT billing claims data, from two hospitals within the Penn Medicine Health System-Penn Presbyterian Medical Center and the Hospital of the University of Pennsylvania. PARTICIPANTS: The cohort consisted of adult patients, aged ≥18 years, undergoing open cardiac valve surgery (repair or replacement), coronary artery bypass graft surgery, or aortic surgery between April 1 and October 31, 2019. INTERVENTIONS: Agreement between TEE identified using CPT billing code(s) (93312-8 with or without 93320-1 or 93325) and TEE identified by manual EMR review. MEASUREMENTS AND MAIN RESULTS: As identified by a reference standard (ie, EMR review) of the 873 cases that met inclusion criteria, 867 (99.31%) cases were performed with TEE and six cases were performed without TEE (<1%). Of the 867 cases performed with TEE, CPT code(s) correctly identified 866 cases, as indicated by having at least one of the CPT codes (93312-8 with or without 93320-1 or 93325). These CPT codes identified intraoperative TEE with a 99.88% sensitivity, 100.00% specificity, 100.00% positive predictive value, and 85.71% negative predictive value. When billing claims for TEE were restricted to the CPT code 93312 alone, the results were identical. CONCLUSIONS: Billing claims using CPT code(s) identified true intraoperative TEE with a high sensitivity, specificity, excellent positive predictive value, and moderate negative predictive value. These results demonstrated that claims data are a valuable data source from which to study the effect of TEE in cardiac surgical patients.

Pilot Study Suggests Smartphone Application Knowledge Improves Resident Transesophageal Echocardiography Knowledge: A Randomized Controlled Trial.

OBJECTIVE: The objective of this study was to determine whether an asynchronous smartphone-based application with image-based questions would improve anesthesiology resident transesophageal echocardiography (TEE) knowledge compared with standard intraoperative teaching alone. DESIGN: Prospective, single-blinded, pilot, randomized controlled trial. SETTING: Large university teaching hospital. PARTICIPANTS: Participants were anesthesiology residents on their cardiac anesthesiology rotation. INTERVENTIONS: EchoEducator, a TEE image-based smartphone application of learning content through questions, was developed. Content was derived from the Examination of Special Competence in Basic Perioperative Transesophageal Echocardiography and the Objective Structured Clinical Examination portion of the APPLIED Examination and focused on identification of basic TEE views, cardiac structures, and pathology. Residents were randomly assigned to receive access to either the application or to standard intraoperative teaching. Thirty residents met inclusion criteria, and 18 residents completed the study. A pre-intervention assessment was given at the beginning of the rotation, and a post-intervention assessment was given after 2 weeks. MEASUREMENTS: The primary outcome was the difference between the post-test score and the pre-test score. Standard bivariate statistics and the chi-square test were used for categorical variables, and the Student t test was used for continuous variables. Tests were 2-sided, and statistical significance was set at p < 0.05. The intervention group demonstrated a greater increase in score; (+19.19% [95% confidence interval 4.14%-34.24%]; p = 0.02) compared with the control group. CONCLUSIONS: This study supports the hypothesis that use of a smartphone-based asynchronous educational application improves TEE knowledge compared with traditional modalities alone. This supports an opportunity to improve medical education by expanding the role of web-based asynchronous learning.

Transesophageal Echocardiography, Acute Kidney Injury, and Length of Hospitalization Among Adults Undergoing Coronary Artery Bypass Graft Surgery.

OBJECTIVE: To test the association between transesophageal echocardiography (TEE) and incidence of acute kidney injury and length of hospitalization among United States adults undergoing isolated coronary artery bypass graft (CABG) surgery. DESIGN: This was an observational, retrospective cohort analysis. SETTING: This study used a multicenter claims dataset from a commercially insured population undergoing CABG surgery in the United States between 2004 and 2016. PARTICIPANTS: Adults aged 18 years or older with continuous insurance enrollment and an absence of renal-related diagnoses before the index CABG surgery. INTERVENTIONS: Receipt of TEE within 1 calendar day of the index CABG surgery date. MEASUREMENTS AND MAIN RESULTS: Of 51,487 CABG surgeries, 5,361 (10.4%; [95% confidence interval [CI]: 10.1-10.7%]) developed acute kidney injury and the mean length of hospitalization was 8.8 days (95% CI: 8.7-8.8). The TEE group demonstrated a greater absolute risk difference (RD) for acute kidney injury by multiple linear regression, overall, (RD=+1.0; [95% CI: 0.4-1.5%]; p < 0.001) and among a low-risk subgroup (RD=+1.0; [95% CI: 0.4-1.6; p = 0.002), but not by instrumental variable analysis (RD=+0.9 [95% CI: -1.1 to 2.9%]; p = 0.362). The TEE group demonstrated a longer length of hospitalization by multiple linear regression, overall (+2.0%; [95% CI: 1.1-2.9%]; p < 0.001), among a low-risk subgroup (+2.2%; [95% CI: 1.2-3.2%]; p < 0.001), and by instrumental variable analysis (+10.3%; [95% CI: 7.0-13.7%]; p < 0.001). CONCLUSIONS: TEE monitoring in CABG surgery was not associated with a lower incidence of acute kidney injury or decreased length of hospitalization. These findings highlight the importance of additional work to study the clinical effectiveness of TEE in CABG surgery.

The Effect of Sedation on Long-Term Psychological Impairment After Extracorporeal Life Support.

OBJECTIVE: This retrospective study aimed to identify the association between long-term psychological impairment and total sedation received during venovenous extracorporeal life support (VV-ECLS) for acute respiratory failure (ARF). DESIGN: This observational retrospective study compared characteristics between patients with and without long-term psychological morbidity at long-term follow-up after VV-ECLS for ARF. SETTING: A single institutional experience in a quaternary referral academic medical center in the United States. PATIENTS: Patients who received VV-ECLS for ARF between January 1, 2015, and April 1, 2017, were identified for selection. Presence of psychiatric morbidity (anxiety and/or depression) was determined with the Hospital Anxiety and Depression Subscale battery at long-term follow-up. INTERVENTIONS: No interventions were made during this retrospective observational study. MEASUREMENTS AND MAIN RESULTS: A total of 42 patients (21 male, 21 female, median age 49 [interquartile range {IQR} 36-57]) completed a telephone interview a median of 14.6 (IQR 7.7-21.1) months after ECLS decannulation. Cohorts were defined as possessing any psychiatric morbidity (anxiety and/or depression) as defined by the Hospital Anxiety and Depression Subscale battery (n = 22 [52%]) versus no psychiatric morbidity (n = 20 [48%]) at long-term follow-up. Patients who had clinically significant psychiatric morbidity received a median of 15.0 (IQR 11.0-17.0) days of continuous intravenous sedation compared with patients who had no psychiatric morbidity, who received a median of 10.0 (IQR 6.5-13.5) days of intravenous sedation; (p = 0.02). CONCLUSIONS: This retrospective analysis identified a significant association between the presence of long-term post-VV-ECLS psychiatric symptoms and the total number of days of intravenous sedation.

Practice Pattern Variation in the Use of Transesophageal Echocardiography for Open Valve Cardiac Surgery.

OBJECTIVE: The authors sought to assess for the presence of practice variation in the use of intraoperative transesophageal echocardiography (TEE) for open cardiac valve surgery. DESIGN: This study was a retrospective cohort analysis. SETTING: The administrative claims data used for this investigation were multi-institutional and a representative sample of commercially insured patients in the United States between 2010 and 2015. PARTICIPANTS: The cohort consisted of adult patients, aged 18 years or older, undergoing open mitral valve (MV) or aortic valve (AV) surgery. INTERVENTIONS: This was an observational analysis without interventions. MEASUREMENTS AND MAIN RESULTS: Of 19,386 valve surgeries, 12,313 (64%) underwent AV replacement, 6,192 (32%) underwent MV repair or replacement, and 881 (<5%) underwent both MV and AV surgery. The overall rate of intraoperative TEE was 82% (95% confidence interval [CI]: 81%-82%), less frequently observed in AV procedures compared to MV or combined MV-AV procedures (80% v 85%, p < 0.001). Rates of intraoperative TEE claims varied markedly across U.S. states. After adjustment, the relative odds of an intraoperative TEE claim ranged across states from 0.26 (Louisiana, 95% CI: 0.18-0.36; p < 0.001) to 2.10 (North Carolina, 95% CI: 1.57-2.82; p < 0.001). CONCLUSION: Among adult patients undergoing open AV or MV surgery in the United States, 82% had a claim for an intraoperative TEE with marked variability across U.S. states. Increasing adherence to intraoperative TEE guidelines for valve surgery may represent an unrecognized opportunity to improve the quality of cardiac surgical care.

Abnormal Calcium Levels During Trauma Resuscitation Are Associated With Increased Mortality, Increased Blood Product Use, and Greater Hospital Resource Consumption: A Pilot Investigation.

BACKGROUND: Admission hypocalcemia predicts both massive transfusion and mortality in severely injured patients. However, the effect of calcium derangements during resuscitation remains unexplored. We hypothesize that any hypocalcemia or hypercalcemia (either primary or from overcorrection) in the first 24 hours after severe injury is associated with increased mortality. METHODS: All patients at our institution with massive transfusion protocol activation from January 2013 through December 2014 were identified. Patients transferred from another hospital, those not transfused, those with no ionized calcium (Ca) measured, and those who expired in the trauma bay were excluded. Hypocalcemia and hypercalcemia were defined as any level outside the normal range of Ca at our institution (1-1.25 mmol/L). Receiver operator curve analysis was also used to further examine significant thresholds for both hypocalcemia and hypercalcemia. Hospital mortality was compared between groups. Secondary outcomes included advanced cardiovascular life support, damage control surgery, ventilator days, and intensive care unit days. RESULTS: The massive transfusion protocol was activated for 77 patients of whom 36 were excluded leaving 41 for analysis. Hypocalcemia occurred in 35 (85%) patients and hypercalcemia occurred in 9 (22%). Mortality was no different in hypocalcemia versus no hypocalcemia (29% vs 0%; P = .13) but was greater in hypercalcemia versus no hypercalcemia (78% vs 9%; P < .01). Receiver operator curve analysis identified inflection points in mortality outside a Ca range of 0.84 to 1.30 mmol/L. Using these extreme values, 15 (37%) had hypocalcemia with a 60% mortality (vs 4%; P < .01) and 9 (22%) had hypercalcemia with a 78% mortality (vs 9%; P < .01). Patients with extreme hypocalcemia and hypercalcemia also received more red blood cells, plasma, platelets, and calcium repletion. CONCLUSIONS: Hypocalcemia and hypercalcemia occur commonly during the initial resuscitation of severely injured patients. Mild hypocalcemia may be tolerable, but more extreme hypocalcemia and any hypercalcemia should be avoided. Further assessment to define best practice for calcium management during resuscitation is warranted.

Testing clinical selection criteria for intraoperative transoesophageal echocardiography in isolated coronary artery bypass graft surgery.

Background: There is a lack of evidence associating intraoperative transoesophageal echocardiography (TOE) use with improved outcomes among coronary artery bypass graft (CABG) surgery subpopulations. Methods: This matched retrospective cohort study used a US private claims dataset to compare outcomes among different CABG surgery patient populations with vs without TOE. Statistical analyses involved exact matching on pre-selected subgroups (congestive heart failure, single vessel, and multivessel CABG) and used fine and propensity-score balanced techniques to conduct multiple matched comparisons and sensitivity analyses. Results: Of 42 249 patients undergoing isolated CABG surgery, 24 919 (59.0%) received and 17 330 (41.0%) did not receive TOE. After matching, intraoperative TOE was significantly associated with a lower, 30-day mortality: 2.63% vs 3.20% (odds ratio [OR]: 0.81; 95% confidence interval [CI]: 0.71-0.92; P=0.002). In the subgroup matched comparisons, intraoperative TOE was significantly associated with a lower, 30-day mortality rate among those with congestive heart failure: 4.20% vs 5.26% (OR: 0.78; 95% CI: 0.66-0.94; P=0.007) and among those undergoing multivessel CABG with congestive heart failure: 4.23% vs 5.24% (OR: 0.80; 95% CI: 0.65-0.97; P=0.025), but not among those undergoing multivessel CABG without congestive heart failure: 1.83% vs 2.15% (OR: 0.85; 95% CI: 0.70-1.02; P=0.089, nor any of the remaining three subgroups. Conclusions: Among US adults undergoing isolated CABG surgery, intraoperative TOE was associated with improved outcomes in patients with congestive heart failure (vs without) and among patients undergoing multivessel (vs single vessel) CABG. These findings support prioritised TOE allocation to these patient populations at centres with limited TOE capabilities.

Predictors of Intraoperative Echocardiography: Analysis of The Society of Thoracic Surgeons Database.

BACKGROUND: Intraoperative transesophageal echocardiography (TEE) is associated with improved outcomes after cardiac surgery, but unexplained practice pattern variation exists. This study aimed to identify and quantify the predictors of intraoperative TEE use among patients undergoing isolated coronary artery bypass graft surgery (CABG) or cardiac valve surgery. METHODS: This observational cohort study used The Society of Thoracic Surgeon (STS) Adult Cardiac Surgery Database data to identify and quantify the predictors of intraoperative TEE use among adult patients aged 18 years or more undergoing either isolated CABG or open cardiac valve repair or replacement surgery between January 1, 2011, and December 31, 2019. Generalized linear mixed models were used to measure the relationship between intraoperative TEE and patient characteristics, surgical volume, and geographic location, while accounting for clustering within hospitals (primary analysis) or surgeons (secondary analysis). RESULTS: Of 1,973,655 patients, 1,365,708 underwent isolated CABG and 607,947 underwent cardiac valve surgery. Overall, intraoperative TEE was used in 62% of surgeries. The primary hospital-level generalized linear mixed models analysis demonstrated that the strongest predictor of intraoperative TEE use was the hospital where the surgery occurred-with a median odds ratio for TEE of 10.13 in isolated CABG and 5.30 in cardiac valve surgery. The secondary surgeon-level generalized linear mixed models analysis demonstrated similar findings. CONCLUSIONS: Intraoperative TEE use (vs lack of use) during surgery was more strongly associated with hospital and surgeon practice patterns than with any patient-level factor, surgical volume, or geographic location.

Neighborhood Socioeconomic Status Independently Predicts Outcomes After Mitral Valve Surgery.

BACKGROUND: Socioeconomic status has increasingly recognized influence on outcomes after cardiac surgery. However, singular metrics fail to fully capture the socioeconomic context within which patients live, which vary greatly between neighborhoods. We sought to explore the impact of neighborhood-level socioeconomic status on patients undergoing mitral valve surgery in the United States. METHODS: Adults undergoing first-time, isolated mitral valve surgery were queried from The Society of Thoracic Surgeons Adult Cardiac Surgery Database between 2012 and 2018. Socioeconomic status was quantified using the Area Deprivation Index, a weighted composite including average housing prices, household incomes, education, and employment levels. The associations between regional deprivation, access to mitral surgery, valve repair rates, and outcomes were evaluated using logistic regression. RESULTS: Among 137,100 patients included, patients with socioeconomic deprivation had fewer elective presentations, more comorbidity burden, and more urgent/emergent surgery. Patients from less disadvantaged areas received operations from higher volume surgeons and had higher repair rates (highest vs lowest quintile: 72% vs 51%, P < .001, more minimally-invasive approach (33% vs 20%, P < .001), lower composite complication rate (42% vs 50%, P < .001), and lower 30-day mortality (1.8% vs 3.9%, P < .001). After hierarchical multivariable adjustment, the Area Deprivation Index significantly predicted 30-day mortality and repair rate (P < .001). CONCLUSIONS: In a risk-adjusted national analysis of mitral surgery, patients from more deprived areas were less likely to undergo mitral repair and more likely to have complications. Further work at targeting neighborhood-level disparity is important to improving mitral surgical outcomes in the United States.