Avaliação do sistema renina angiotensina em pacientes portadores de hipertensão pulmonar

Abstract

BACKGROUND: The pulmonary hypertension (PH) is a clinical syndrome recognized by mainteined increased pressure at the pulmonary vascular bed and right cardiac chambers. Three pathogenic mechanisms are involved: disbalance between vasoconstrictor and vasodilator factors, endothelial disfunction and pulmonary vascular remodeling. It has high morbidity and mortality, besides not having cure and presents a little effective treatment. The renin-angiotensin system was recently revised and expanded. There are several studies about its participation in the vascular homeostasis, and is believed that it plays a crucial role in PH. OBJECTIVE: measuring the transpulmonary concentration and activity of different peptides and enzymes of PAH patients and controls. METHODS: we selected 12 pacients who underwent right cardiac catheterization and manometry for clinical suspicion of PAH. Nine of these were diagnosed with PH and three were categorized as controls. Blood samples were collected from all patients from pulmonary artery and aortic root. We used mass spectometry and fluorimetric assays to measure the peptides (AngI, AngII, Ang1-7, Ala) and enzyme activity (ECA, ECA2 e renina). For the univariated analyses we used the t-test, Wilcoxon and Mann-Whitney test. For the multivariated analysis, we used the ANOVA test. The p value for significance was <0,05. RESULTS: we found differences in the plasmatic concentrations of the peptides Ang1-7 and Ala in the pulmonary artery between cases and controls. Both values were higher in cases. The pulmonary artery ratio AngII/Ang1-7 was higher in controls. The pacients with PAH had higher aortic concentrations of Ang1-7 when compared to controls. The pulmonary-aortic ratio of Ala peptide was different than one (=2,27). That suggests its lower concentration at aorta when compared to pulmonary artery in cases. This ratio was significantly different of one in the controls for Ala and for the AngII/Ang1-7 relation. Furthermore, when comparing cases and controls, the mean transpulmonary ratios obtained statistical significance for the Ala peptide. CONCLUSION: These results suggests higher plasmatic concentrations of vasodilator peptides (Ang1-7 e Ala) in the inflow of the pulmonary circulation of the PAH patients when compared to controls. There were, moreover, significant decrease of the Ala peptide at the aortic root when compared to pulmonary artery in patients with PH. Besides, in the control group we observed a higher concentration of Ala in the aortic root (inverse).