The Efficacy of Scoring Balloon Angioplasty in the Treatment of Chronic Thromboembolic Pulmonary Hypertension Based on Optical Coherence Tomography：A Single-center Randomized Controlled

After right heart catheterization,BPA procedures are performed via femoral vein approach. 8-Fr sheath is inserted into the vein and 6-Fr guiding cathater was advanced to the main pulmonary artery through the 8-Fr guiding catheter using a 0.035-inch wire. We select a branch of the pulmonary artery by a 6-Fr guiding catheter (JR4.0). Pulmonary angiography is performed manually using half contrast medium diluted with saline. A 0.014-inch guidewire (Sion) is crossed under the pulmonary angiography, and OCT (Fig.1: Types of lesions) is used for the detection of Lumen diameter (mm), Intimal thickness (mm), Intimal area (mm2), Intimal thickness/lumen diameter, Intimal area/lumen area, which are defined as short diameter assessed by OCT. The balloon size, the expansion pressure and the choice of scoring balloon or plain balloon angioplasty are at the discretion of the operator. Balloon-to-vessel (B/V) ratio is defined as the balloon diameter divided by vessel diameter assessed with OCT (1:0.7-1). Pulmonary arteries with an inner diameter of less than 4mm detected by OCT were selected for BPA performance. Scoring balloon and plain balloon are used in half of pulmonary lesions respectively., use the Plain balloon was used to predilate, If the vascular Lesion is a completely occlusive or the scoring balloon cannot pass through vessels.