Predictors of therapeutic response to specific therapy in distal chronic thromboembolic pulmonary hypertension

Aim. To assess therapeutic response to specific therapy in patients with distal CTEPH who are ineligible for surgical management as pulmonary endarterectomy (PEA) or balloon pulmonary angioplasty (BPA). Materials and methods. The study included inoperable patients with CTEPH (n=53) who are ineligible for surgical management as pulmonary endarterectomy or balloon pulmonary angioplasty. The effectiveness of specific therapy were assessed after dividing the patients into improvement or nonimprovement groups based on the following indicators: functional class I-II (WHO), mean pulmonary artery pressure according to right heart catheterization ≤40 mm Hg, pulmonary vascular resistance ≤400 dyn×s×cm-5, cardiac index ≥2,5 L/min/m2 , decrease in N-terminal brain natriuretic peptide >30%, and increase in 6-minute test distance >30 m at 12th-month follow-up compared to baseline parameters. Results. There were no differences in groups by gender, age, and received specific therapy. Multiple logistic regression was performed, resulting in a model for predicting clinical improvement with sensitivity (57,1%) and specificity (87,1%), p=0,002. It was revealed, that the absence of the loss of pulmonary vascularity by X-ray at the time of verification of the diagnosis in patients with CTEPH by 5,91 times increases the chance of achieving clinical improvement after 12 months of the specific therapy, while the absence of signs of heart failure by 5,79 times, and degree of pulmonary valve insufficiency 0-1 according to echocardiography by 9,2 times, respectively. Conclusion. Early initiation of specific therapy in inoperable CTEPH patients due to distal lesions with the absence of severe vascular remodeling and heart failure symptoms leads to the better therapeutic response after 12 months of treatment.