Clinical and radiological characteristics of CTEPH patients without a history of acute venous thromboembolism

Chronic thromboembolic pulmonary hypertension (CTEPH) is thought to result from incomplete resolution of vascular obstruction following acute pulmonary embolism (PE). However, at least 25% of CTEPH patients do not have a documented episode of acute venous thromboembolism (VTE). We hypothesized that patients without a VTE in their past medical history have different clinical and radiological characteristics compared to CTEPH patients with previous acute VTE. Baseline data and history of VTE were retrospectively retrieved from the charts of all CTEPH patients included between 2014-2022 in the Amsterdam UMC CTEPH registry. CT pulmonary angiography, right heart catheterization and pulmonary function tests were performed in all patients. Subsegmental disease was defined by the presence of a contrast defect in the pulmonary arterial vessels after the first arterial branch division. A total of 262 CTEPH patients were included; 47 patients (18%) did not have previous acute VTE. Baseline radiological assessment showed that subsegmental disease was more frequent in patients without previous VTE (n=16/43; 35%, 95%CI: 22-49) compared to patients with previous VTE (n= 27/214; 13% (95%CI: 9.0-18), OR: 2.6 (95% CI: 1.2-5.7). The patients without previous VTE were less frequently assigned to pulmonary endarterectomy (PEA) compared to patients with acute VTE (30%, (95% CI: 18-44) versus 56%, (95% CI: 49-62); OR: 0.5 (95% CI: 0.2-0.9). Comorbidities, pulmonary function and hemodynamics were not different. CTEPH patients without previous VTE, had more distally located disease on imaging compared to CTEPH patients with previous VTE and were less often subjected to PEA.