[Meta-analysis of risk factors for recurrent pulmonary thromboembolism].

Objective: To evaluate the risk factors of recurrent pulmonary thromboembolism (PTE) through Meta-analysis.

Methods: Chinese Journal Full-text Database, Chinese Biomedical Database, PubMed and Foreign Medical Journal Full-Text Service were searched for the paper relating to the risk factors of recurrent PTE from January 1995 to May 2011. And the references of these studies were also examined. Observational studies (cohort & case control) were assessed according to the method of quality assessment suggested within the references. Randomized control trials (RCTs) were assessed by the Jadad scale. Software RevMan 5.1 was used to examine the heterogeneity of trials. The fixed or random effect model was pooled to calculate the risk ratio (RR). And the results were expressed by RR (95%CI).

Results: Forty-two trials including 36 909 cases of PTE and/or deep vein thrombosis were analyzed. And the following factors were relative to recurrence: elevated D-dimer (1.77 (1.34 - 2.36), P = 0.000), idiopathic PTE (1.82 (1.61 - 2.05), P = 0.000), right ventricular dysfunction (RVD) (persistent RVD vs RVD regression (8.71 (2.38 - 31.91), P = 0.001); persistent RVD vs non-RVD (2.45 (1.26 - 4.76), P = 0.008), short anticoagulation duration (1.73 (1.32 - 2.28), P = 0.000), increased endogenous thrombin generation capacity (1.89 (1.39 - 2.56), P = 0.000), elevated factor VIII (1.96(1.40 - 2.74), P = 0.000), positive antiphospholipid antibodies (5.64 (4.09 - 7.77), P = 0.000), anti-thrombin defect (2.45 (1.26 - 4.76), P = 0.008) and males (1.47 (1.06 - 2.03), P = 0.020), etc. When multiple factors co-existed, the risk of recurrence became more obvious.

Conclusions: Elevated D-dimer, idiopathic PTE and many other factors may influence the recurrence of pulmonary embolism. And most recurrent patients have two or more factors.