PT  - JOURNAL ARTICLE
AU  - I. M. Robbins
AU  - S. M. Kawut
AU  - D. Yung
AU  - M. P. Reilly
AU  - W. Lloyd
AU  - G. Cunningham
AU  - J. Loscalzo
AU  - S. E. Kimmel
AU  - B. W. Christman
AU  - R. J. Barst
TI  - A study of aspirin and clopidogrel in idiopathic pulmonary arterial hypertension
AID  - 10.1183/09031936.06.00095705
DP  - 2006 Mar 01
TA  - European Respiratory Journal
PG  - 578--584
VI  - 27
IP  - 3
4099  - http://erj.ersjournals.com/content/27/3/578.short
4100  - http://erj.ersjournals.com/content/27/3/578.full
SO  - Eur Respir J2006 Mar 01; 27
AB  - Idiopathic pulmonary arterial hypertension (IPAH) is characterised by in situ thrombosis and increased thromboxane (Tx) A2 synthesis; however, there are no studies of antiplatelet therapy in IPAH. The aim of the current study was to determine the biochemical effects of aspirin (ASA) and clopidogrel on platelet function and eicosanoid metabolism in patients with IPAH. A randomised, double-blind, placebo-controlled crossover study of ASA 81 mg once daily and clopidogrel 75 mg once daily was performed. Plasma P-selectin levels and aggregometry were measured after exposure to adenosine diphosphate, arachidonic acid and collagen. Serum levels of TxB2 and urinary metabolites of TxA2 and prostaglandin I2 (Tx-M and PGI-M, respectively) were assessed. A total of 19 IPAH patients were enrolled, of whom nine were being treated with continuous intravenous epoprostenol. ASA and clopidogrel significantly reduced platelet aggregation to arachidonic acid and adenosine diphosphate, respectively. ASA significantly decreased serum TxB2, urinary Tx-M levels and the Tx-M/PGI-M ratio, whereas clopidogrel had no effect on eicosanoid levels. Neither drug significantly lowered plasma P-selectin levels. Epoprostenol use did not affect the results. In conclusion, aspirin and clopidogrel inhibited platelet aggregation, and aspirin reduced thromboxane metabolite production without affecting prostaglandin I2 metabolite synthesis. Further clinical trials of aspirin in patients with idiopathic pulmonary arterial hypertension should be performed.