Progression of chronic thromboembolic pulmonary disease without pulmonary hypertension in a case with JAK2 V617F mutation.

UNLABELLED: Chronic thromboembolic pulmonary disease (CTEPD) is characterized by persistent obstruction of pulmonary arteries with organized thrombotic materials. Patients with CTEPD without pulmonary hypertension (PH) are generally considered unlikely to progress to chronic thromboembolic pulmonary hypertension (CTEPH). Here, we report a case of a 75-year-old woman with essential thrombocythemia harboring JAK2 V617F mutation, who had a history of acute pulmonary embolism. Initial evaluation of contrast-enhanced computed tomography and pulmonary angiography revealed organized thrombi predominantly in the right main and lobar pulmonary arteries, accompanied by perfusion defects on lung perfusion scintigraphy. Right heart catheterization (RHC) showed a mean pulmonary arterial pressure (mPAP) of 18 mmHg, leading to a diagnosis of CTEPD without PH. As the patient declined invasive treatment, she was followed with anticoagulation therapy alone. Three years later, her symptoms worsened, and RHC revealed an elevated mPAP of 33 mmHg, along with slight progression of thrombotic lesions and newly identified calcified deposits. She again refused invasive treatment and died one year later despite medical therapy. This case suggests that the JAK2 V617F mutation could be a risk factor for progression from CTEPD without PH to CTEPH, underscoring the importance of close follow-up and early consideration of invasive treatment in such patients. LEARNING OBJECTIVE: This case highlights that chronic thromboembolic pulmonary disease without pulmonary hypertension can progress to chronic thromboembolic pulmonary hypertension, particularly in patients with high-risk features such as the JAK2 V617F mutation. It underscores the importance of careful long-term follow-up and early consideration of invasive treatment despite initially normal hemodynamics.