Perspective:

Nagarajan and colleagues performed a meta-analysis examining the prognostic value of cardiac troponin measurement in patients with chronic stable systolic and/or diastolic heart failure (HF). The following are 10 points to remember about this review:

1. In contrast to acute decompensated HF, few studies have examined troponin levels in stable chronic HF patients. Only 16 studies were eligible for inclusion in the meta-analysis.

2. In general, 64% (range 43-80%) of stable HF patients had positive high-sensitivity (hs) troponins, and 31% (11-54%) had positive low-sensitivity troponins.

3. Only one study has compared outcomes based on high- versus low-sensitivity troponins in stable HF patients.

4. Overall, patients with elevated troponins have nearly threefold higher risk of mortality (hazard ratio [HR], 2.9 [2.0-4.0]; range in HR, 1.2-7.3 among studies).

5. The point estimated for mortality was higher with hs-troponin measurement (HR, 3.2 [1.7-6.2]) than low-sensitivity troponins (HR, 2.6 [1.9-3.4]), but differences were not statistically different (p = 0.54).

6. The higher point estimate for mortality with hs-troponins in the meta-analysis conflicted results published in the single direct comparison study of high- versus low-sensitivity troponins (see #3 above). Thresholds for ‘positivity’ with hs-troponins likely impact the predictive accuracy of the test.

7. Troponin I and troponin T provided statistically similar risks of mortality.

8. Elevated cardiac troponins may result from irreversible cardiomyocyte damage or from reversible damage with troponin release in the setting of supply-demand mismatches or impairment in pinocystosis.

9. The authors argue that future studies should investigate outcomes in patients who have positive hs-troponins, but negative low-sensitivity measures. The change in troponin level trend would also be of interest.

10. The clinical response to patients with positive troponins in the setting of other known risk measures and models (Seattle Heart Failure Model, etc.) should also be investigated.