Does Aspirin inhibit vasoconstriction and platelet aggregation by blocking synthesis of the prostaglandin?

Aspirin (acetlysalicylic acid) is an irreversible inhibitor of the cyclo-oxygenase (COX-I and COX-II) enzymes which are responsible for the conversion of arachidonic acid into the prostaglandins. It is supposed that this happens due to the acetylation effects of aspirin.