Prognostic Role of Platelets in Pulmonary Arterial Hypertension

Platelets have emerged as immune-inflammatory cells that may contribute to the pathogenesis and prognosis of pulmonary arterial hypertension (PAH), although their clinical relevance remains uncertain. We retrospectively evaluated platelet indices in 243 patients with PAH from a tertiary referral center and compared them with 50 normopressoric controls undergoing right heart catheterization. Platelet count, mean platelet volume (MPV), and survival outcomes were analyzed. PAH patients exhibited significantly lower platelet counts compared with controls (203,666 ± 90,466 vs. 246,025 ± 126,778/µL; p < 0.001). MPV was also reduced in idiopathic PAH compared with controls (9.8 ± 1.68 vs. 10.44 ± 1.25 fL; p < 0.05). Survival analysis demonstrated that PAH patients with platelet counts within the normal range (150,000-450,000/µL) had significantly better outcomes than those with thrombocytopenia (p < 0.05). These findings suggest that alterations in platelet indices may reflect disease severity and prognosis in PAH. While exploratory and subject to potential confounders such as connective tissue disease, the results reinforce the potential role of platelets as biomarkers in pulmonary vascular disease and highlight the need for further mechanistic and longitudinal studies.