d ‐dimer is a predictor of clot resolution in patients with pulmonary thromboembolism: A retrospective cohort study

BACKGROUND: This study assessed predictors of pulmonary thromboembolism (PE) resolution and their implications for clinical outcome. METHOD: A total of 150 patients with acute PE diagnosed by computed tomography pulmonary angiography (CTPA) were included. All patients received anticoagulant therapy for 3-6 months and were followed-up for at least 2 years. d-dimer levels in plasma were assayed at the first admission and during follow-up. RESULTS: The rate of CTPA-confirmed PE resolution was 48.67% at 6 months, 68% at 12 months, and 78.67% at 24 months. Thirty-nine patients had recurrent thrombosis after anticoagulation therapy was stopped, whereas 93 patients had complete resolution. The initial d-dimer level positively correlated with the pulmonary artery obstruction index (PAOI) (r = 0.21; P = 0.015), but did not significantly differ between patients experiencing resolution or recurrence. In contrast, the follow-up mean d-dimer level was significantly higher in the recurrent group (P < 0.001), and this level was an independent risk factor for recurrent PE after the termination of anticoagulation treatment (OR 1.003, 95%CI 1.002 to 1.004; P < 0.001). Higher initial thromboembolic burden measured by PAOI was associated with residual thromboemboli (P = 0.004) and recurrence (P = 0.03), but was not an independent risk factor for either. CONCLUSIONS: Elevated d-dimer is an independent risk factor for PE recurrence. A higher initial thromboembolic burden may be associated with unresolved thromboemboli or recurrence.