Assessment of platelet dysfunction in patients with pulmonary arterial hypertension

Abstract

Background: Pulmonary arterial hypertension (PAH) is a disease characterized by vasoconstriction, remodeling and thrombotic pulmonary vascular lesions. Although alterations in hemostasis are consistently observed in PAH patients, their extent and their role in the progression of the disease remain largely unclear. Aims: The aim of this study is to evaluate primary platelet- related hemostasis, using point- of care methods, like the Platelet- Function Analyzer (PFA-100) and Light Transmission Aggregometry (LTA). Methods: The study group consisted of 21 patients with PAH, diagnosed according to current ESC/ERS guidelines. Blood samples were obtained directly from the pulmonary artery. The PFA-100 testing was performed using collagen epinephrine (CEPI) - coated cartridges. Platelet activation in LTA was induced by ADP and epinephrine. Results: 53,4% of the patients presented prolonged CEPI closure times with PFA-100 testing [median (IQR), 161 (122–192)]. ADP- induced platelet aggregation was reduced [60 (45–70)] in 33,3% of the patients and disaggregation (not normally seen in healthy individuals) was present in another 57,14%. In addition, 53,4% of the population presented reduced EPI- induced aggregation. No significant correlation was found between the degree of platelet dysfunction and the mean pulmonary arterial pressure [mean 47.6 ± 12.9 mmHg] or the pulmonary vascular resistance [9.3±4.2 Wood Units]. Conclusions: These preliminary data provide evidence of significant impaired primary hemostasis and severe platelet dysfunction demonstrated in the vast majority (90%) of PAH patients.