In addition, cine-CT allows detection of pannus or thrombus on or adjacent Table 23. Systemic Fibrinolysis Versus Surgery for Prosthetic Valve Thrombosis Favor Surgery Favor Fibrinolysis Readily available surgical expertise No surgical expertise available Low surgical risk High surgical risk Contraindication to fibrinolysis No contraindication to fibrinolysis Recurrent valve thrombosis First-time episode of valve thrombosis NYHA class IV NYHA class I, II, or III ) Small clot ( 0.8 cm2 ) LA thrombus No LA thrombus Concomitant CAD in need of revascularization No or mild CAD Other valve disease No other valve disease Possible pannus Thrombus visualized Patient choice Patient choice CAD indicates coronary artery disease; and NYHA, New York Heart Association. Adapted from several references.2,5,7,13,14 CLINICAL STATEMENTS AND GUIDELINES to the valve, which is not possible with fluoros- copy. When excessive gradients are present with normal leaflet motion and no thrombus, either patient prosthesis mismatch or pannus forma- tion is present (or both). 3. Stenosis of a bioprosthesis may occur because of progressive structural valve degeneration or pan- nus formation. However, stenosis can also occur because of a thin layer of thrombus on the valve cusps, which is reversible with oral anticoagula- tion therapy. Bioprosthetic valves are less throm- bogenic than their mechanical counterparts. However, the diagnosis of subclinical bioprosthetic valve thrombosis has increased with the use of CT imaging and as a function of the increased num- bers of implanted bioprosthetic valves, including When there is clinical evidence of biopros- thetic valve stenosis, 3D TEE or 4D CT imaging may be useful to detect a layer of valve thrombus as the cause of the obstruction. 11.8.2. Intervention for Prosthetic Valve Stenosis Recommendations for Intervention for Prosthetic Valve Stenosis Referenced studies that support the recommendations are summarized in Online Data Supplement 40. 