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

Introduction: 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.

Methods: 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.

Results: 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.

Conclusion: 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.