Whether elevated serum troponin levels identify patients with acute pulmonary embolism at high risk of short-term mortality or adverse outcome is undefined. We performed a meta-analysis of studies in patients with acute pulmonary embolism to assess the prognostic value of elevated troponin levels for short-term death and adverse outcome events (composite of death and any of the following: shock, need for thrombolysis, endotracheal intubation, catecholamine infusion, cardiopulmonary resuscitation, or recurrent pulmonary embolism). Unrestricted searches of MEDLINE and EMBASE bibliographic databases from January 1998 to November 2006 were performed using the terms "troponin" and "pulmonary embolism." Additionally, review articles and bibliographies were manually searched. Cohort studies were included if they had used cardiac-specific troponin assays and had reported on short-term death or adverse outcome events. A random-effects model was used to pool study results; funnel-plot inspection was done to evaluate publication bias; and I2 testing was used to test for heterogeneity. Data from 20 studies (1985 patients) were included in the analysis. Overall, 122 of 618 patients with elevated troponin levels died (19.7%; 95% confidence interval [CI], 16.6 to 22.8) compared with 51 of 1367 with normal troponin levels (3.7%; 95% CI, 2.7 to 4.7). Elevated troponin levels were significantly associated with short-term mortality (odds ratio [OR], 5.24; 95% CI, 3.28 to 8.38), with death resulting from pulmonary embolism (OR, 9.44; 95% CI, 4.14 to 21.49), and with adverse outcome events (OR, 7.03; 95% CI, 2.42 to 20.43). Elevated troponin levels were associated with a high mortality in the subgroup of hemodynamically stable patients (OR, 5.90; 95% CI, 2.68 to 12.95). Results were consistent for troponin I or T and prospective or retrospective studies. Elevated troponin levels identify patients with acute pulmonary embolism at high risk of short-term death and adverse outcome events.
