Application of homocysteine as a non-invasive and effort-free measurements for risk assessment of patients with pulmonary hypertension

Background: Current guideline-recommended multiparameters used to assess the risk levels of pulmonary arterial hypertension (PAH) are invasive hemodynamic measurements or effort-dependent exercise tests. Serum natriuretic peptide is only one kind of effort-free biomarker that has been adopted for risk assessment. This study aimed to investigate the application of homocysteine as a non-invasive and effort-free measurement for the risk assessment of patients with PAH. Methods: Samples of 50 patients diagnosed with PAH via right heart catheterization were obtained, and the patients were divided into low-, intermediate-and high-risk groups for further analysis. Additionally, serum N-terminal prohormone of B-type natriuretic peptide (NT-proBNP) and homocysteine levels of monocrotaline (MCT)-induced PAH rats were analyzed at each week with progressed severity of PAH, and they were sacrificed on day 28 with pathology being assessed. Results: Hyperhomocysteinemia was an independent predictor (odds ratio [OR]: 1.256; 95% confidence interval [CI]: 1.002–1.574) and showed a linear correlation with NT-proBNP. Hyperhomocyst-einemia could discriminate between low/intermediate and high-risk levels in PAH with a cut-off value in 12 µmol/L. Moreover, the elevated homocysteine levels by weeks in MCT rats also demonstrated the association between homocysteine and the severity of PAH. Conclusions: Homocysteine can be a non-invasive and effort-free risk assessment for patients with pulmonary hypertension. Homocysteine level had a linear correlation with NT-proBNP level, and patients with hyperhomocysteinemia had a higher risk level, higher NT-proBNP level, and decreased lower diffusing capacity for carbon monoxide. The correlation between homocysteine level and PAH severity was also demonstrated in MCT rats.