Epidemiology, risk factors and diagnosis of chronic thromboembolic pulmonary hypertension: data from the registry

Aim . To analyze the epidemiology, risk factors and baseline clinical data of patients included in the registry of patients with chronic thromboembolic pulmonary hypertension (CTEPH). Material and methods . This prospective, observational, single-­center study inclu­ded 286 patients (women, 51% (n=148)) with a newly diagnosed CTEPH and trea­ted at the Almazov National Medical Research Center named from January 1, 2014 to December 31, 2023. The diagnosis of CTEPH was verified according to the 2015 European Society of Cardiology criteria and clinical guidelines of the Russian Ministry of Health. To evaluate the effectiveness of the multidisciplinary "CTEPH team" patients were divided into two subgroups based on the time of CTEPH diagnosis verification as follows: group 1 (n=147) included patients examined and treated from January 1, 2014 to December 31, 2018; group 2 (n=139) — from January 1, 2019 to December 31, 2023. Results . The mean age of patients at diagnosis was 56 [43; 66] years. The majority had an advanced stage of the disease (class III, n=176, 62%), and the time from symptom onset to diagnosis was 2,6 [1,4; 4,6] years. In addition, 40,7% of patients were St. Petersburg residents, while the disease prevalence in St. Petersburg at the end of 2023 was 21,1 cases per million people. An increase in the incidence of CTEPH in St. Petersburg was noted from 1,56 to 2,86 cases per 1 million population. A verified pulmonary embolism in history was recorded in 71% (n=204) of patients. In half of the cases, there was massive pulmonary embolism. Analysis of risk factors for CTEPH demonstrated a high prevalence of antiphospholipid syndrome (11%) and splenectomy (5%), and also identified such probable risk factors as large arteriovenous malformation and large uterine fibroids. When comparing the clinical and laboratory characteristics of the two groups depending on the inclusion period, patients in group 1 were distinguished by more pronounced remodeling and right heart dysfunction according to echocardiography (right atrial area, right ventricle to left ventricle ratio, pulmonary artery diameter, left ventricular stroke volume), in group 2 by higher N-terminal pro-brain natriuretic peptide (1512,0 [511,5; 2702,0] vs 816,5 [197,0; 2235,5], p=0,004). However, no differences were found in pulmonary circulation hemodynamics or diagnosis verification time. In group 2, patients with CTEPH class I were more often detected (9% vs 1%, p=0,041). No diffe­rences were found in the number of patients with empirically prescribed specific therapy for pulmonary arterial hypertension. Conclusion . A low incidence of CTEPH was demonstrated, as well as longer dia­gnosis times associated with more pronounced pulmonary hemodynamics changes when compared with international registries. A positive trend was noted, with an increase in newly diagnosed patients with lower functional class and less pronounced right heart remodeling, likely due to improved patient routing for pulmonary hypertension.