Preoperative β-Blocker Use and Mortality and Morbidity Following CABG Surgery in North America
Bibliographic record
Abstract
CONTEXT: beta-Blockade therapy has recently been shown to convey a survival benefit in preoperative noncardiac vascular surgical settings. The effect of preoperative beta-blocker therapy on coronary artery bypass graft surgery (CABG) outcomes has not been assessed. OBJECTIVES: To examine patterns of use of preoperative beta-blockers in patients undergoing isolated CABG and to determine whether use of beta-blockers is associated with lower operative mortality and morbidity. DESIGN, SETTING, AND PATIENTS: Observational study using the Society of Thoracic Surgeons National Adult Cardiac Surgery Database (NCD) to assess beta-blocker use and outcomes among 629 877 patients undergoing isolated CABG between 1996 and 1999 at 497 US and Canadian sites. MAIN OUTCOME MEASURE: Influence of beta-blockers on operative mortality, examined using both direct risk adjustment and a matched-pairs analysis based on propensity for preoperative beta-blocker therapy. RESULTS: From 1996 to 1999, overall use of preoperative beta-blockers increased from 50% to 60% in the NCD (P<.001 for time trend). Major predictors of use included recent myocardial infarction; hypertension; worse angina; younger age; better left ventricular systolic function; and absence of congestive heart failure, chronic lung disease, and diabetes. Patients who received beta-blockers had lower mortality than those who did not (unadjusted 30-day mortality, 2.8% vs 3.4%; odds ratio [OR], 0.80; 95% confidence interval [CI], 0.78-0.82). Preoperative beta-blocker use remained associated with slightly lower mortality after adjusting for patient risk and center effects using both risk adjustment (OR, 0.94; 95% CI, 0.91-0.97) and treatment propensity matching (OR, 0.97; 95% CI, 0.93-1.00). Procedural complications also tended to be lower among treated patients. This treatment advantage was seen among the majority of patient subgroups, including women; elderly persons; and those with chronic lung disease, diabetes, or moderately depressed ventricular function. Among patients with a left ventricular ejection fraction of less than 30%, however, preoperative beta-blocker therapy was associated with a trend toward a higher mortality rate (OR, 1.13; 95% CI, 0.96-1.33; P =.23). CONCLUSIONS: In this large North American observational analysis, preoperative beta-blocker therapy was associated with a small but consistent survival benefit for patients undergoing CABG, except among patients with a left ventricular ejection fraction of less than 30%. This analysis further suggests that preoperative beta-blocker therapy may be a useful process measure for CABG quality improvement assessment.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".