PURPOSE: Previous studies demonstrated that hyperhomocysteinemia is an independent risk factor for congestive heart failure, stroke and thromboembolism. In patients with pulmonary arterial hypertension, the plasma levels of total homocysteine and their relation to disease severity are unknown.
METHODS: Serial measurements of homocysteine plasma levels, NT-proBNP serum levels and 6 minute walk distance in 35 patients with severe pulmonary arterial hypertension (12 idiopathic, 23 thromboembolic, 19 female, 16 male) diagnosed by right heart catheterization (WHO functional class 3, mean pulmonary artery pressure 46±6mmHg; mean±SD). Right ventricular size, systolic pulmonary artery pressure (PAP) and systolic strain were assessed by echocardiography.
RESULTS: 24 patients (69%) had elevated plasma homocysteine levels (13.7±5.4 μmol/l, normal <12 μmol/l). There was a significant correlation between plasma homocysteine and NT proBNP serum levels (r = 0.42, p=0.004). Moreover, there was a relation between homocysteine plasma levels and right ventricular size (r= 0.51, p=0.002), and right ventricular strain (r=0.42, p=0.003) respectively. In contrast, homocysteine plasma levels were independent from systolic pulmonary artery pressure and 6 minute walk distance (r = 0.18, r = 0.25, p>0.05 for both comparisons). Homocysteine plasma levels did not differ between male and female patients.
CONCLUSION: In patients with severe pulmonary arterial hypertension, the elevated homocysteine plasma levels and their significant correlation with right ventricular performance might be an indicator of peripheral pulmonary microembolisms. The pathomechanisms and the prognostic significance of elevated homocysteine in PAH need further investigation.
CLINICAL IMPLICATIONS: Noninvasive monitoring of patients with pulmonary arterial hypertension. New therapeutic options.
DISCLOSURE: Arthur Filusch, None.