45 year old patient. how much of an increased risk does he have if he is taking a blood thinner (eliquis) of having a hemorrhagic stroke? does the risk go up if he also have a dva (developmental venous anomaly). by how much?

Taking a "blood thinner" such as Eliquis will not actually cause bleeding (as with a ruptured blood vessel causing a hemorrhagic stroke), but may prolong the hemorrhage if not pharmacologically arrested. Anticoagulant therapy for other reasons (coronary thrombosis) is important to prevent heart attacks, and other clotting related damage.

"Blood thinners" such as Eliquis do not cause bleeding, regardless of a venous anomaly, many of which are trivial and lifelong. But if a hemorrhagic stroke were to ensue, the bleeding would be more vigorous due to the presence of a medication affecting hemostasis.