High Sensitivity Troponin I for Risk Assessment in Patients with Atrial Fibrillation: Insights from the ARISTOTLE Trial
Background—High sensitivity troponin-I (hs-TnI) measurements improves risk assessment for cardiovascular events in many clinical settings, the added value in atrial fibrillation (AF) patients has not been described.
Methods and Results—At randomization hs-TnI was analyzed in 14,821 AF patients in the ARISTOTLE trial comparing apixaban with warfarin. The associations between hs-TnI concentrations and clinical outcomes were evaluated using adjusted Cox analysis. The hs-TnI assay detected troponin (≥1.3 ng/L) in 98.5% patients, 50% had levels >5.4, 25% levels >10.1, and 9.2% levels ≥23 ng/L (the 99th percentile in healthy). During median 1.9 years follow-up annual rates of stroke or systemic embolism ranged from 0.76% in the lowest hs-TnI quartile to 2.26% in the highest quartile (>10.1ng/L). In multivariable analysis hs-TnI was significantly associated with stroke or systemic embolism, adjusted hazard ratio (HR) 1.98 (1.42-2.78), p=0.0007. hs-TnI was also significantly associated with cardiac death; annual rates ranged from 0.40% to 4.24%, HR 4.52 (3.05-6.70), p<0.0001, in the corresponding groups, and for major bleeding HR 1.44 (1.11-1.86), p=0.0250. Adding hs-TnI levels to the CHA2DS2VASc-score improved C-statistics from 0.629 to 0.653 for stroke or systemic embolism, and from 0.591 to 0.731 for cardiac death. There were no significant interactions with study treatment.
Conclusions—Troponin-I is detected in 98.5% and elevated in 9.2% of AF patients. The hs-TnI level is independently associated with a raised risk of stroke, cardiac death, and major bleeding and improves risk stratification beyond the CHA2DS2VASc-score. The benefits of apixaban as compared with warfarin are consistent regardless of hs-TnI levels.
Clinical Trial Registration Information—ClinicalTrials.gov. Identifier: NCT00412984.
- Received September 16, 2013.
- Revision received October 28, 2013.
- Accepted October 30, 2013.