Also, EHRA type 1 is broadly similar to the previously described mechanical and rheumatic mitral valvular AF (MARM-AF).444 Nondrug Alternatives and Perioperative Considerations Occlusion of the LAA With Devices or Surgical Techniques: Approximately 90% of the thrombi found in patients with non-valvular AF and 57% of the thrombi found in valvular AF are located in the LAA.445 TABLE 11 ] Summary Box: EHRA Categorization in Relation to the Type of OAC Used in Patients With AF De nition EHRA type 1 VHD AF patients with VHD needing therapy with a vitamin K antagonist (VKA)  Mitral stenosis (moderate-severe, of rheumatic origin)  Mechanical prosthetic valve replacement EHRA type 2 VHD AF patients with VHD needing therapy with a VKA or an NOAC, also taking into consideration CHA2DS2-VASc score risk factor components  Mitral regurgitation  Mitral valve repair  Aortic stenosis  Aortic regurgitation  Tricuspid regurgitation  Tricuspid stenosis  Pulmonary regurgitation  Pulmonic stenosis  Bioprosthetic valve replacements  Trans-aortic valve intervention CHA2DS2-VASc congestive heart failure, hypertension, age $ 75 (doubled), diabetes, stroke (doubled)-vascular disease, age 65-74 and sex category (female); EHRA Evaluated Heart Valves, Rheumatic or Arti cial; VHD valvular heart disease. See Table 1 legend for expansion of other abbreviations. LAAO using speci c percutaneous devices (WATCHMAN, Amplatzer Cardiac Plug, or WaveCrest device or the Lariat endocardial and epicardial ligation technique) or occlusion during a cardiac surgery procedure with either LAA amputation and closure or a stapler device have been proposed and tested for patients with AF at high risk of stroke in the presence of a high risk of bleeding or in the presence of contraindications to OACs. 