Serum cardiac troponin elevation predicts mortality in patients with pulmonary hypertension: A meta-analysis of eight cohort studies.

OBJECTIVE: To determine the association of serum cardiac troponin (cTn) with the mortality of pulmonary hypertension (PH) patients via a meta-analysis.

DATE SOURCE: We searched PubMed and EMBASE from inception to October 25, 2017.

STUDY SELECTION: The reference lists of the retrieved articles were also consulted. The Q test and I2 test were used for to assess heterogeneity. The relationship between cTn elevation and mortality was analysed. Studies were stratified according to type of troponin (cTnT vs cTnI), region (Europe vs America) and follow-up length (≤3 years vs >3 years).

RESULTS: Eight studies with 739 patients were included in the meta-analysis. Cardiac troponin elevation ranged from 14.3% to 94.5%. Overall, 48.8% (39/80) of patients with elevated cTn died compared to 18.6% (45/242) of patients with normal cTn levels. These findings showed cTn elevation was significantly related to an increased mortality risk in PH patients [hazard ratio (HR) = 3.05, 95% confidence interval (95% CI) = 2.16-4.32, I2  = 24.9%]. cTnI was better at predicting mortality than cTnT (HR = 3.37, 95%CI = 2.05-5.55 vs HR = 2.80, 95%CI = 1.97-3.98, respectively). American populations had increased mortality compared to European populations (HR = 4.23, 95%CI = 2.29-7.80 vs HR = 2.70, 95% CI = 1.95-3.74, respectively). This finding was independent of the follow-up length of the studies (≤3 years: HR = 2.36, 95%CI = 1.65-3.38; >3 years: HR = 4.55, 95%CI = 2.80-7.39).

CONCLUSIONS: Although different studies detected the expression cTnT or cTnI by various methods, the mortality in the cTn-positive group was higher than that in the cTn-negative group. Serum cTn elevation emerged as an independent predictor of increased risk of mortality in PH patients.