Elevated troponin I level assessed by a new high-sensitive assay and the risk of poor outcomes in patients with acute heart failure.

BACKGROUND

The interpretation and clinical usefulness of elevated levels of cardiac troponins in acute heart failure (AHF) remain controversial. We aimed to characterize the relationship between changes in cardiac troponin I (measured using a new high-sensitive immunoassay by single-molecule counting technology, Singulex, Alameda, USA; hs-TnI) during first 48h of hospital stay and patients' characteristics and the outcomes.

METHODS AND RESULTS

We measured hs-TnI at baseline, after 24 and 48h in 130 AHF patients (mean age: 65±13years, 77% men). The percentage of patients with elevated hs-TnI (i.e., above the upper reference limit [URL]>10.19pg/mL) were: on admission - 59%, after 24h - 61%, and after 48h - 58%. Elevated baseline level of hs-TnI was associated with more severe dyspnoea on admission but neither peak level nor changes in hs-TnI during first 48h were related to the dyspnoea severity or magnitude of dyspnoea relief. During 1-year follow-up there were 32 (25%) cardiovascular deaths. Neither absolute baseline nor peak values of hs-TnI predicted cardiovascular mortality. Only changes in hs-TnI were independently associated with cardiovascular mortality with the strongest relationship seen in peak change in hs-TnI: patients with an increase vs. remaining patients - hazard ratio (95% confidence interval): 3.22 (1.52-6.82)p=0.002.

CONCLUSIONS

Using the new assay (proved to be more sensitive that the other available troponin assays) we observed that approximately 60% of patients with AHF presented elevated hs-TnI above URL during first 48h of hospital stay. Only significant increase in hs-TnI predicted cardiovascular mortality.