Incidence and risk factors of chronic thromboembolic pulmonary hypertension in patients with diagnosis of pulmonary embolism for the first time in real world.

Background: The incidence and risk factors of chronic thromboembolic pulmonary hypertension (CTEPH) in patients with acute pulmonary embolism (PE) have been well reported. However, in real world, patients diagnosed with PE for the first time were usually composed of acute PE, sub-acute PE, and chronic PE, and the cumulative incidence and risk factors of CTEPH in this cohort were still unknown.

Methods: A prospective, long-term, follow-up study was conducted to assess the incidence of symptomatic CTEPH in consecutive patients with PE diagnosed for the first time. Patients with unexplained persistent dyspnea during follow-up underwent transthoracic echocardiography and, if the findings indicated pulmonary hypertension, ventilation-perfusion lung scanning and right heart catheterization. CTEPH was confirmed if perfusion defects were present, mean pulmonary artery pressure (mPAP) ≥25 mmHg and pulmonary artery wedge pressure (PAWP) ≤15 mmHg.

Results: The cumulative incidence of CTEPH in patients with PE diagnosed for the first time was 11.2% at 3 months, 12.7% at 1 year, 13.4% at 2 years, and 14.5% at 3 years. The following factors increased the risk of CTEPH: time from symptoms to treatment of PE ≥1 month (odds ratio (OR), 14.77), intermediate (OR, 37.63) to high risk PE (OR, 39.81), segmental and sub-segmental branch location of embolism (OR, 8.30) and PE-related primary risk factors (OR, 5.01). 9.4% of CTEPH patients developed from acute PE, and 90.6% from sub-acute and chronic PE.

Conclusions: In real world, CTEPH is a relatively common and serious complication in PE patients diagnosed for the first time. Early diagnosis and treatment of PE will decrease the incidence of CTEPH in these unspecified patients.