Cardiac Troponins in Low-Risk Pulmonary Embolism Patients: A Systematic Review and Meta-Analysis

BACKGROUND: Patients with low-risk pulmonary embolism (PE) should be considered as per current scoring systems for ambulatory treatment. However, there is uncertainty whether patients with low scores and positive troponins should require hospitalization. METHODS: We searched MEDLINE, SCOPUS, and Cochrane Library databases from inception to December 2016 and collected longitudinal studies that evaluated the prognostic value of troponins in patients with low-risk PE. The primary outcome measure was 30-day all-cause mortality. We calculated odds ratio (OR), likelihood ratios (LRs), and 95% confidence intervals (CI) by using randomeffects models. RESULTS: The literature search identified 117 candidate articles, of which 16 met the criteria for review. Based on pulmonary embolism severity index (PESI) or simplified PESI score, 1.2% was the all-cause mortality rate across 2,662 participants identified as low-risk. A positive troponin status in patients with low-risk PE was associated with an increased risk of 30-day all-cause mortality (odds ratio [OR]: 4.79; 95% confidence interval [CI]: 1.11 to 20.68). The pooled likelihood ratios (LRs) for all-cause mortality were positive LR 2.04 (95% CI, 1.53 to 2.72) and negative LR 0.072 (95% CI, 0.37 to 1.40). CONCLUSIONS: The use of positive troponin status as a predictor of increased mortality in low-risk PE patients exhibited relatively poor performance given the crossed negative LR CI (1.0) and modest positive LR. Larger prospective trials must be conducted to elucidate if patients with low-risk PE and positive troponin status can avoid hospitalization.