Distribution of thrombus predicting severe reperfusion pulmonary edema after pulmonaryendarterectomy

Patients underwent pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension (CTEPH). This study aimed to investigate the effect of thrombus distribution on the occurrence of severe reperfusion pulmonary edema (RPE) and identify specific parameters for predicting severe RPE.Patients with CTEPH who underwent PEA surgery were retrospectively analyzed. The thrombus in pulmonary arteries were evaluated through computed tomography pulmonary angiography. Based on presence of prolonged artificial ventilation, extracorporeal membrane oxygenation required, or perioperative death due to RPE, the patients were divided into the severe RPE and without severe RPE groups.Among the 77 patients (29 women), 16 (20.8%) patients developed severe RPE. The right major pulmonary artery (RPA) (0.64[0.58, 0.73] vs 0.58[0.49, 0.64]; p = 0.008) and pulmonary artery trunk (PAT) thrombus ratios (0.48[0.44, 0.61] vs 0.42[0.39, 0.50]; p = 0.009) (the PAT ratio is expressed as the sum of the right middle lobe clot burden and right lower lobe clot burden divided by the total clot burden multiplied by 100) of the severe RPE group was significantly higher than that of the without severe RPE group. Receiver operator characteristics curve identified a PAT ratio of 43.4% as the threshold with areas under the curve = 0.71(95%CI 0.582; 0.841) for the development of severe RPE (sensitivity 0.875, specificity 0.541). The logistic regression analysis demonstrated that age, period from symptom onset to PEA, NT-pro BNP, preoperative mPAP, preoperative PVR, RPA ratio, and PAT ratio were associated with the development of severe RPE. Multivariable logistic regression analysis revealed PAT ratio (odds ratio = 10.2; 95% confidence interval 1.87, 55.53, P = 0.007) and period from symptom onset to PEA (OR = 1.01; 95% CI = 1.00-1.02, P = 0.015) as independent risk factors for the development of severe RPE.The thrombus distribution could be a key factor in the severity of RPE. PAT ratio and medical history could predict the development of severe RPE.