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.