Angiographic classification of total occlusion and its implication on balloon pulmonary angioplasty

Abstract

Aims: Despite refinements in balloon pulmonary angioplasty (BPA), total occlusion remains a challenge in chronic thromboembolic pulmonary hypertension (CTEPH). Owing to their low success and high complication rates, most interventional cardiologists are reluctant to address total occlusion, and there is a paucity of literature on BPA performance in total occlusion. We aimed to classify total occlusion according to morphology and present an illustrative approach for devising a tailored treatment strategy for each distinct type of total occlusion.

Methods and results: All patients diagnosed with CTEPH who underwent BPA between May 2018 and May 2022 at Fuwai Hospital in Beijing, China, were included retrospectively. A total of 204 patients with CTEPH who underwent BPA were included in this study. Among these, 38 occluded lesions were addressed in 33 patients. Based on the morphology, we categorized the lesions into three groups: pointed-head, round-head, and orifice occlusions. Pointed-head occlusion could be successfully addressed using soft-tip wire, round-head occlusion warranted hard-tip wire and stronger backup, and orifice occlusion warranted the strongest backup force. The success rates for each group were as follows: pointed-head (95.45%), round-head (46.15%), and orifice occlusion (33.33%), with orifice occlusion having the highest complication rate (50%). The classification of occlusion was associated with BPA success (round-head occlusion vs. pointed-head occlusion, OR 24.500, 95% CI 2.498-240.318, P = 0.006; orifice occlusion vs. pointed-head occlusion, OR 42.000, 95% CI 3.034-581.434, P = 0.005).

Conclusions: Occlusion morphology has a significant impact on BPA success and complication rates. A treatment strategy tailored to each specific occlusive lesion, as outlined in the present study, has the potential to serve as a valuable guide for clinical practitioners.

Keywords: Balloon pulmonary angioplasty; Chronic thromboembolic pulmonary hypertension; Classification of total occlusion; Pulmonary angiogram.

Figure 1

Model figure of three types of occlusions. The figure demonstrated the features of three types of lesions. Pointed‐head occlusion was featured by pointed occlusive cap with no trace of vessels distal to the lesion. In pointed‐head occlusion, the tip of wire matches to the size of occlusive cap and the both sides of occlusive cusp provide support for wire manipulation. Round‐head occlusion was featured by wide occlusive cap, leaving a pocket like opacity at the proximal of occluded arteries and no blood flow to the distal vessels. In round‐head occlusion, lack of support from both sides of lesion increases the difficulty of wire manipulation, where the force of interventionists could not transmit to the tip of wire and the tip of wire would shake during the intervention. Orifice occlusion was featured by complete occlusion of pulmonary lobe or segments with no sign of beginner. Positioning the guidewire coaxially to the occluded vessels is also extremely difficult and there is barely backup force for subsequent wire manipulation.

Figure 2

Three types of occlusions before and after treatment. (A, a) Pointed‐head occlusion in anteroposterior position before BPA treatment; red arrow refers to location of occlusion and there is no trace of flow distal to the lesions. (A, b) Pointed‐head occlusion in anteroposterior position after BPA treatment, red arrow refers to location of occlusion and there is trace of flow distal to the lesions after treatment. (B, a) Round‐head occlusion in right anterior oblique 45° position before BPA treatment; Red arrow refers to location of occlusion and there is no trace of flow distal to the lesions. (B, b) Round‐head occlusion in right anterior oblique 45° position after BPA treatment; Red arrow refers to location of occlusion and there is trace of flow distal to the lesions after treatment. Green arrow refers to occurrence of dissection during the treatment. (C, a) Orifice occlusion in left anterior oblique 45° position before BPA treatment; Red arrow refers to location of occlusion and there is no trace of flow distal to the lesions. (C, b) Orifice occlusion in anteroposterior position after BPA treatment. Red arrow refers to location of occlusion and there is trace of flow distal to the lesions after treatment.