Zhyvylo I. Systemic circulation arteries structure and function in patients with idiopathic pulmonary arterial hypertension and pulmonary arterial hypertension associated with congenital heart diseases

The aim of the research was to study the elastic properties of systemic circulation arteries in patients with idiopathic pulmonary arterial hypertension (PAH) and PAH associated with congenital heart diseases (CHD). Diagnostic improvement and prognostic criterias of idiopathic PAH were developed based on the complex assessment of the structure and function of the systemic circulation arteries using the method of arterial stiffness determining, irrespectively of systemic arterial pressure level. The study included 152 patients: 45 of them were diagnosed with idiopathic PAH (1st group), 40 patients with PAH associated with CHD (2nd group), 32 patients with arterial hypertension (AH) (3rd group) and 35 healthy patients in screening group (4th group). The levels of the office systolic arterial pressure (AP), diastolic AP and central AP were significantly higher in the AH group than in other groups. Carotid-femoral pulse wave velocity (cfPWV) was also significantly higher in patients with AH compared with other groups. CfPWV was 24 % higher in patients with AH than in patients with idiopathic PAH, and 36 % higher than in patients with PAH associated with CHD. Increase of cfPWV more than 10 m/s was observed in 77 % of patients with AH, while in the group of patients with idiopathic PAH it was over 10 m/s in 20 % of the patients, and in the group of PAH associated with CHD and control group - in 10 % of the patients, respectively. Level of cardio-ankle vascular index (CAVI) dimension on the both sides was the same in patients with idiopathic PAH and AH patients, that which indicates an infraction changes abnormalities of the elastic properties of systemic circulation arteries in patients with idiopathic PAH. In our research, patients with idiopathic PAH with impaired functionality (6MWD < 330m) had a significantly higher NT-proBNP, right atrium size index and pressure, estimated by right heart catheterization, a significantly lower TAPSE and SvO2. CAVI index in this group was also significantly higher than in patients with preserved functionality (6 MWD > 330 m). During 3 years of follow-up 10 patients (22,2 %) with idiopathic PAH had died of cardio-pulmonary causes: 8 patients had died due to heart failure progression and 2 patients had a sudden cardiac death. They formed the first subgroup. The second subgroup was formed by 35 patients (78,8 %) with idiopathic PAH who survived. In first subgroup NT-proBNP level 23 times exceeded the normal range and it was 4 times higher in comparison with the second subgroup. In the first subgroup, hyperuricemia was observed in every second patient, and in the second - in every fifth patient. In first subgroup on 6 MWD patients covered distanse on 87 metres less than in survival group. These data indicate a significant functionality impairment in patients with favorable prognosis. The analysis of CAVI examinations showed that its level in first group was significantly higher compared with the results of the second subgroup. Thus, CAVI can be used as an indicator of systemic circulation arteries stiffness and may be considered an additional risk factor of complications and 1-year mortality in patients with idiopathic PAH.