Estudo das funções ventriculares esquerda e direita na hipertensão arterial pulmonar

• Ano de defesa: 2012
• Autor(a) principal: Fernanda Brito de Oliveira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Função ventricular direita; Esquistossomose; Função ventricular esquerda; Hipertensão arterial pulmonar; Strain bidimensional; Função ventricular esquerda/fisiologia; Ecocardiografia/métodos; Função ventricular direita/fisiologia; Hipertensão pulmonar/fisiopatologia; Ventrículos do coração/ultrassonografia; Diagnóstico diferencial; Resistência vascular; Medicina tropical
• Link de acesso: http://hdl.handle.net/1843/BUBD-9XCJ7W

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by elevated pulmonary vascular resistance (PVR) that leads to enlargement and dysfuntion of the right ventricle (RV) and may be associated with early mortality. In Brazil, hepatoesplenic schistosomiasis is an important cause of PAH. The assessment of RV function is important in the management of patients with PAH. Echocardiography is an important tool for screening and evaluation of those patients. However, quantification of RV function is still challenging due to its complex geometry. 2D-strain is a new method for accurate assessment of contractility. Objectives: The aim of this study was to analyze RV function in patients with PAH by conventional echocardiography and by 2D strain, and to investigate if there was any difference related to PAH etiology. The impact of RV pressure overload on the left ventricle (LV) was also investigated. Methodology: This is an observational, transversal study performed from December 2010 until March 2012. A total of 37 patients with PAH and 38 healthy controls with similar ages were included. Plasma levels of brain natriuretic peptide (BNP) and functional capacity, assessed by the 6- min walk test (6MWT), were obtained. Results: Mean age was 46,4 years and 11 patients (69%) were females. 6MWT correlated with age and right atrial area. The main determinants of BNP were age and PVR. Longitudinal global RV strain was lower in patients (16.0 ± 4.1 x 23.1 ± 3.2, p < 0.001) than in controls, even when the RV free and septal walls were analyzed separately. RV diastolic diameter, systolic pulmonary arterial pressure (SPAP) and the left atrial volume (LAV) correlated independently with global RV strain. LV global longitudinal and radial strains were reduced in patients than in controls, even when septal wall was excluded from the analysis. Global circumferencial strain was similar for both groups; only septal circumferencial strain was lower in patients (20.8 ± 10.3 x 25.0 ± 4.5, p = 0.040). Patients with schistosomiasis were compared with patients with other etiologies of PAH. Although systolic pulmonary artery pressure (SPAP) did not differ between those two groups 75.0 [59/109] x 93.5 [71/119], p= 0.214), PVR was lower (1.14 [0.9/1.8] x 1.8 [1.3/3.1], p = 0.004) and tricuspid annular motion was higher (18.2 ± 3.3 x 15.2 ± 3.1, p = 0.008) in patients with schistosomiasis. Conclusion: Patients with PAH had lower global RV strain than controls. RV strain correlated independently with RV diastolic diameter, SPAP and LAV. LV global longitudinal and radial strains were reduced in patients with PAH, suggesting an early impairment of LV contractility in these patients. This can lead to the hypothesis that the LV can also be involved in PAH, probably due to changes in its geometry and to ventricular interaction.