Abstract 19170: Lesion Morphological Classification by Optical Coherence Tomography to Predict Therapeutic Efficacy After Balloon Pulmonary Angioplasty

Introduction: Conventionally, angiographic classification has been used for chronic thromboembolic pulmonary hypertension (CTEPH). However, a classification based on lesion morphology is needed in the era of balloon pulmonary angioplasty (BPA). We sought to propose a classification of CTEPH based on lesion morphology detected by optical coherence tomography (OCT) and to evaluate its association with physiological stenosis assessed with a pressure wire and therapeutic efficacy in BPA. Methods: We analyzed 43 lesions in 17 patients who were treated with BPA under OCT and pressure-wire guidance from November 2012 to March 2015. OCT findings were classified into the following 4 categories: 1) mono-hole, 2) septum, 3) multi-hole with thin wall, and 4) multi-hole with thick wall. Results: Angiographic findings did not match the specific morphologic classification based on OCT findings. At the pre-BPA assessment, the pressure ratio of the septum type was significantly higher than that of the mono-hole and multi-hole with thick wall types (p = 0.026 and 0.047, respectively). Under the OCT-based classification, more than 50% of the septum and multi-hole with thin wall types could accomplish >0.8 of the mean pressure ratio assessed by a pressure wire, and these proportions were significantly higher than those of the other 2 types: mono-hole and multi-hole with thick wall (p = 0.044). Based on angiographic classification, accomplishment of this criterion was not significantly different among angiographic types. Conclusions: OCT-based morphologic lesion classifications in CTEPH were useful to predict whether the lesion stenosis could improve to the acceptable level mediated by BPA.