Enhancing preoperative assessment in chronic thromboembolic pulmonary hypertension: A comprehensive analysis of interobserver agreement and proximity-based CT pulmonary angiography scoring

Background: Surgical risk in chronic thromboembolic pulmonary hypertension (CTEPH) depends on the proximity of thromboembolism on pulmonary angiography (CTPA). We assessed interobserver agreement for the quantification of thromboembolic lesions in CTEPH using a CTPA scoring index.Methods: Forty CTEPH patients (mean age, 58 +/- 16 years; 19 men) with preoperative CTPA who underwent pulmonary endarterectomy (PEA) 2020-09/2021) were retrospectively included. Three radiologists scored each CTPA for chronic thromboembolism (occlusions, eccentric thickening, webs) using a 32-vessel model of the pulmonary vasculature, with interobserver agreement evaluated using Fleiss' kappa. CT level of disease determined by the most proximal chronic thromboembolism: level 1 (main pulmonary artery), 2 (lobar), 3 (segmental) and 4 (subsegmental), compared to surgical level at PEA.Results: Interobserver agreement for CT level of disease was moderate overall (kappa = 0.52). Agreement was substantial overall at the main/lobar (kappa, mean = 0.71) when excluding the left upper lobe (kappa = 0.17). Though segmental and subsegmental agreement suffered (kappa = 0.31), we substantial agreement for occlusions (kappa = 0.72) compared to eccentric thickening (kappa = 0.45) and webs (kappa = 0.14). Correlation between CT level surgical level was strong overall (tau b = 0.73) and in the right lung (tau b = 0.68), but weak in the left lung (tau b = 0.42) (p < 0.05). Radiologists over-and underestimated the proximal extent of disease in right and left lung, respectively.Conclusions: CT level of disease demonstrated good agreement between radiologists and was highly predictive of the surgical level in CTEPH. Occlusions were the most reliable sign of chronic thromboembolism and are important in assessing the segmental vasculature.

Automated summary

This study assessed interobserver agreement for quantification of thromboembolic lesions in chronic thromboembolic pulmonary hypertension (CTEPH) using a CTPA scoring index. The results showed moderate agreement among different observers for the level of disease, with substantial agreement at the main/lobar level and weaker agreement at the segmental and subsegmental levels.Occlusions were the most reliable sign of chronic thromboembolism, and CT level of disease demonstrated good agreement between radiologists and was highly predictive of the surgical level in CTEPH.