Low dose Aspirin
I would consider white willow bark (which aspirin’s derived from). The other strongest natural blood thinners (anticoagulants/antiplatelets/antithrombotics?) I know of (that are free from the harmful effects of aspirin) are UVBI, protease (particularly nattokinase and lumbrokinase), fish oil, vit. E complex, ginkgo, and Panax notoginseng. Other blood thinners include alfalfa grass, avocado, bilberries, cat’s claw, celery, CoQ10, cranberries, garlic, ginger, ginseng, grapefruit, green tea, horse chestnut, licorice, B complex (specifically niacin), onion, papaya, pomegranate, red clover, tempeh (fermented soy), turmeric, wheat grass, lemon, dark grapes, Pycnogenol; quercetin, nettle, and grounding (Earthing.com).
You can just stop aspirin which has a 10 day effect on platelet aggregation, and immediately start Boulouke Lumbrokinase or other enzyme such as Nattokinase/serripeptase right away, as these will not cause bleeding except possibly in very large amounts. I once had a patient on coumadin due to chronic atrial fibrillation. He went on vacation for a week and forgot to take the prescription with him. He did have Nattokinase and NattoSerrizyme with him so he took 6 pills of each twice a day to compensate for stopping coumadin. When he returned, we checked his INR and it was 5.6 (therapeutic is 1-3) so clearly these products are effective! (He did not have bleeding or bruising issues either, even at what was clearly too high a dose.