Hi P - an alternative to aspirin - which is used as a prescribed medicine to affect the blood flow - hence is used by heart attack surrerers for example along with other drugs - is to take a regular dose of flax seed.
Hemp oil, hemp seed and saff flower oil are also useful - these all contain ideal ratios of omega 3 to omega 6 and have been found to help on several levels in various tests on their efficacy.
They can benefit with cholesterol, skin conditions, hormone balances and even claim help with lowering risks of cancer - but I think there are many factors that can affect that, but as the seeds are vegetable origin, they are easy to digest, are sustainable and will not upset the system if you overindulge. Aspirin can irritate stomach lining and again as above - speak to the GP before taking any drugs at all.
Loads of info on the hemp, flax and saff flower seeds and oils on the web for you to play with.
Hope this helps.