Hemodynamic Parameter Assessment and Mortality Risk Factor Identification in Patients with Pulmonary Arterial and Chronic Thromboembolic Pulmonary Hypertension. Summary of the Doctoral Thesis

Abstract

Pulmonary hypertension (PH) is a debilitating disease associated with high mortality requiring multidisciplinary approach. PH is defined by a mean pulmonary artery pressure ≥ 25 mmHg at rest, measured during right heart catheterization. Nowadays, PH is classified into 5 groups. The best studied types of PH are group 1 – pulmonary arterial hypertension (PAH) and group 4 – chronic thromboembolic pulmonary hypertension (CTEPH). Both PAH and CTEPH are also classified as rare diseases. Systematic data collection of PAH and CTEPH patients began in 2007 as a part of PhD research. This paper presents the data obtained over period of nine years. Aim. The purpose of this study was identify mortality risk factors for PAH and CTEPH patients in Latvia. Methods. This is a prospective, single–center study of PAH and CTEPH patient clinical manifestation, hemodynamic parameters and survival rate at the time of diagnosis. Results. From September 1, 2007 to December 31, 2016 PH was confirmed in 503 cases. 130 patients with PAH and 44 patients with CTEPH satisfied the inclusion (exclusion) criteria and were included in present study. In PAH patient group 27 % (n=35) of patients were male, HR – 1.13 (0.57–2.21); median age was 65 (47–71) years, HR per 1 year – 1.01 (0.99–1.03); mean six–minute walk test result – 322 ± 122 m; HR for a result ≤ 300 m – 3.36 (1.27–8.89); mean pulmonary artery pressure – 49 ± 18 mmHg, HR per 1 mmHg – 1.00 (0.99–1.02); mean right atrial pressure– 11 ± 7 mmHg, HR per 1 mmHg – 1.10 (1.05–1.16); median pulmonary vascular resistance – 6.6 (4.4–10.9) WU, HR per 1 WU – 1.02 (0.96–1.08); mean cardiac index – 2.47 ± 0.73 l/min/m2, HR per 1 l/min/m2 – 1.02 (0.64–1.61). In CTEPH patient group 39 % (n=17) of patients were male, HR – 0.72 (0.22–2.36); median age was 67 (47–73) years, HR per 1 year – 0.97 (0.94–1.00); mean six–minute walk test result – 274 ± 111 m; HR for a result ≤ 300 m – 1.91 (0.73–4.64); mean pulmonary artery pressure – 51 ± 15 mmHg, HR per 1 mmHg – 1.05 (1.01–1.10); mean right atrial pressure — 13 ± 8 mmHg, HR per 1 mmHg – 1.07 (0.99–1.14); median pulmonary vascular resistance – 10.3 (6.9–13.8) WU, HR per 1 WU – 1.13 (1.00–1.27); mean cardiac index – 1.93 ± 0.74 l/min/m2, HR per 1 l/min/m2 – 0.90 (0.31–2.61). One, three and five year survival rate in PAH and CTEPH patient groups were: 88 % and 84 %, 73 % and 76 %, 58 % and 44 %, respectively. Conclusions. Survival prognosis of PAH and CTEPH patients depends on several hemodynamic parameters obtained during right heart catheterization, partially confirming that the hypothesis made at the beginning of study is correct. In PAH patient group both lower 6 minute walk test result (especially ≤ 300 m) and higher right atrial pressure were associated with increased mortality. In CTEPH patient group lower age (≤ 65 years), higher mean pulmonary artery pressure and higher pulmonary vascular resistance were associated with increased mortality. Multivariate analysis showed that in PAH patient group lower 6 minute walk test result and higher right atrial pressure were independently associated with increased mortality. Latvian PAH patients had the second worst 1–year survival among those reported in Europe and in CTEPH patient group it was the worst among reported. A state–level PH and its subgroup registry was created in Latvia based on current study and its data.