The significance of historical troponin elevation in acute heart failure: Not as reassuring as previously assumed.

BACKGROUND

Historical cardiac troponin (cTn) elevation is commonly interpreted as lessening the significance of current cTn elevations at presentation for acute heart failure (AHF). Evidence for this practice is lacking. Our objective was to determine the incremental prognostic significance of historical cTn elevation compared to cTn elevation and ischemic heart disease (IHD) history at presentation for AHF.

METHODS

A total of 341 AHF patients were prospectively enrolled at five sites. The composite primary outcome was death/cardiopulmonary resuscitation, mechanical cardiac support, intubation, new/emergent dialysis, and/or acute myocardial infarction (AMI)/percutaneous coronary intervention (PCI)/coronary artery bypass grafting (CABG) at 90 days. Secondary outcomes were 30-day AMI/PCI/CABG and in-hospital AMI. Logistic regression compared outcomes versus initial emergency department (ED) cTn, the most recent electronic medical record cTn, estimated glomerular filtration rate, age, left ventricular ejection fraction, and IHD history (positive, negative by prior coronary workup, or unknown/no prior workup).

RESULTS

Elevated cTn occurred in 163 (49%) patients, 80 (23%) experienced the primary outcome, and 29 had AMI (9%). cTn elevation at ED presentation, adjusted for historical cTn and other covariates, was associated with the primary outcome (adjusted odds ratio [aOR] 2.39, 95% confidence interval [CI] 1.30-4.38), 30-day AMI/PCI/CABG, and in-hospital AMI. Historical cTn elevation was associated with greater odds of the primary outcome when IHD history was unknown at ED presentation (aOR 5.27, 95% CI 1.24-21.40) and did not alter odds of the outcome with known positive (aOR 0.74, 95% CI 0.33-1.70) or negative IHD history (aOR 0.79, 95% CI 0.26-2.40). Nevertheless, patients with elevated ED cTn were more likely to be discharged if historical cTn was also elevated (78% vs. 32%, p = 0.025).

CONCLUSIONS

Historical cTn elevation in AHF patients is a harbinger of worse outcomes for patients who have not had a prior IHD workup and should prompt evaluation for underlying ischemia rather than reassurance for discharge. With known IHD history, historical cTn elevation was neither reassuring nor detrimental, failing to add incremental prognostic value to current cTn elevation alone.