Conference: 2012 International PHA Conference and Scientific Sessions
Release Date: 06.22.2012
Presentation Type: Abstracts
Rui Plácido, João S. Marques, Susana R. Martins, Cláudia Jorge, Carina Calisto, Susana Gnçalves, Sónia Ribeiro, Ana G. Almeida, A. Nunes Diogo.
Centro Hospitalar Lisboa Norte, Hospital de Santa Maria – Lisbon, Portugal
INTRODUCTION: The distance of the 6-minute walking test (6MWT) is one of the most frequently used clinical variables that has a predicting relevance of the pulmonary arterial hypertension (PAH) prognosis.
GOAL: To establish what are the clinical, echocardiographic and laboratorial criteria that determine the 6MWT results in patients with PAH.
METHODS: prospective coorte study in 30 patients (pts) with PAH confirmed by hemodynamic evaluation, on a 12-month time lapse. The pts were submitted to a serial of clinical, laboratorial and echocardiographic evaluations. In the clinical evaluation we used the 6MWT distance, whereas in the laboratorial evaluation there was a dosing of the neuro-hormonal activation biomarkers. In the echocardiographic study there was an evaluation of the conventional parameters and also of the parameters for the right-ventricle (RV) myocardial deformation.
RESULTS: There is a correlation between the 6MWT distance and several clinical basal parameters: Borg’s pre-test classification (R=-0,46; p=0,038) and WHO’s functional class (p=0,029). There was an inverse correlation between 6MWT distance and the serum concentration of aldosterone (R=-0,46; p=0,030), renin (R=-0,43; p=0,046), adrenomedullin (ADM) (R=-0,53; p=0,009) e endothelin-1 (ET-1) (R=-0,42; p=0,044), and a direct correlation with natremia (R=0,55; p=0,006). Within the new biomarkers, only the ANP’s variation had a correlation with the variation of the 6MWT’s distance (basal time – 3m; R=-0,55; p=0,026 / time 6-12m; R=-0,96; p=0,011). The echocardiographic variables correlated with the 6MWT distance were the systolic and protodiastolic peak’s of the RV’s global strain rate (R=0,49; p=0,038 and R=-0,55; p=0,018, respectively). The conventional parameters of the RV’s function didn’t show any statistically significant relation. From these parameters the protodiastolic peak of the RV’s global strain rate and the natremia (R=0,70; p=0,008) were independent predictors of the 6MWT distance in a multivariate analysis.
CONCLUSION: The 6MWT distance correlated with the activation of the renin-angiotensin-aldosterone system and parameters for the RV myocardial deformation. The ADM and ET-1 biomarkers have proven to be usefull in the prediction of the functional capacity, and the ANP’s variation can provides information about its variation.