Thromboxane

Thromboxane-A synthase, an enzyme found in platelets, converts the arachidonic acid derivative prostaglandin H2 to thromboxane.

If the cap of a vulnerable plaque erodes or ruptures, as in myocardial infarction, platelets stick to the damaged lining of the vessel and to each other within seconds and form a plug.

These "Sticky platelets" secrete several chemicals, including thromboxane A2 that stimulate vasoconstriction, reducing blood flow at the site.

Omega-3 fatty acids are metabolized to produce higher levels of TxA3, which is relatively less potent than TxA2 and PGI3; therefore, there is a balance shift toward inhibition of vasoconstriction and platelet aggregation.

It is believed that this shift in balance lowers the incidence of myocardial infarction (heart attack) and stroke.