anticoagulation with warfarin is recommended with an INR target of 3.0 (range, 2.5 3.5).33,473 The inci- dence of thromboembolism is higher in patients with mechanical prostheses in the mitral compared with the aortic position, and the rate of thrombo- embolism is lower in patients with a higher INR goal. In the GELIA study (German Experience With Low Intensity Anticoagulation) of patients with a mechanical mitral prosthesis, a lower INR (2.0 3.5) was associated with lower survival rates than a higher target INR range (2.5 4.5).458 Although routine addition of aspirin to warfarin therapy in patients with mechanical valves is not recom- mended, patients with a history of ischemic stroke or TIA before the mechanical valve surgery repre- sent a group with an inherently higher thrombo- embolic risk in whom the protection from recurrent thromboembolic events associated with the com- bination of aspirin and warfarin therapy may out- weigh the competing bleeding risk.459 3. In the absence of AF, observational studies have reported conflicting results with regard to the asso- ciation between nonrheumatic mitral valve disease or native aortic disease and increased risk of throm- An early case-con- trol study reported that mitral valve prolapse was associated with an increased risk for ischemic More recent studies have not confirmed Observational studies have consistently shown that the risk for stroke in people with mitral valve prolapse is low (<1% At least 4 population-based cohort studies have evaluated the association between mitral annular calcification and stroke.478,479,484,485 Figure 3. Recommended antithrombotic regimen in patients with history of ischemic stroke or transient ischemic attack (TIA) and different valvular heart disease conditions. Colors correspond to Class of Recommendation in Table 3. 