Background: Percutaneous transluminal coronary angioplasty (PTCA) is an acute, localized stimulus to platelet and vascular function. Periprocedural cardiovascular complications are reduced by moderate-dose aspirin (ASA), presumably due to inhibition of thromboxane (TX) A2.
Methods and results: Excretion of TXA2 and prostacyclin (PGI2) metabolites in urine increased during PTCA. Pretreatment for 3 days with either moderate- (325 mg/day) or low-dose (80 mg/day) ASA inhibited the increase in both eicosanoids. Pretreatment for 3 weeks with fish oil (10 g/day) only partially suppressed TXA2. Formation of trienoic eicosanoids and accumulation of omega-3 fatty acids in platelet membranes confirmed fish oil ingestion. Although basal PGI2 was not inhibited, the PTCA-related increment was suppressed.
Conclusions: PTCA results in an acute, transient alteration of eicosanoid biosynthesis consistent with accelerated platelet-vascular interactions. Pretreatment for 3 days with moderate or low doses of ASA suppresses TXA to a similar extent during PTCA, and their effects on acute cardiovascular complications of this procedure are likely to be comparable. It is unlikely that even prolonged pretreatment with fish oil can substitute for the platelet inhibitory action of ASA during PTCA. Suppression of PGI2 may contribute to the residual acute periprocedural complication rate in patients taking ASA.