Evaluation of organized thrombus in distal pulmonary arteries in patients with chronic thromboembolic pulmonary hypertension using cone-beam computed tomography

Balloon pulmonary angioplasty (BPA) is an emerging treatment for inoperable chronic thromboembolic pulmonary hypertension (CTEPH) patients. However, the approach to use to identify distal thrombi suitable for BPA has not yet been established. The purpose of this work was therefore to evaluate distal chronic thromboembolic lesions for BPA using cone-beam computed tomography (CBCT). Thirty-two patients (men/women: 9/23) with CTEPH who underwent CBCT before BPA were enrolled. We assessed representative forms of chronic thromboembolic lesions in 94 segmental and/or 208 subsegmental branches according to CBCT and compared the results to the findings of selective angiography during BPA. We classified CTEPH lesions into five subtypes as follows: type 1a (11.1 %), webs; type 1b (14.4 %), web with severe narrowing of the subsegmental artery; type 2, (58.2 %) web and slits; type 3 (2.4 %), slits; and type 4 (13.9 %), pouch defect with incomplete obstruction of subsegmental branches or complete occlusion. In our study, 92.6 % of the CTEPH lesions diagnosed by CBCT were highly consistent with the findings of selective angiography during BPA. CBCT clearly revealed and classified distal lesions in CTEPH patients. The CBCT findings for distal lesions were highly consistent with those of selective angiography during BPA. CBCT could be a useful modality to detect target lesions before BPA.