Intervention for Mixed MS and AS Almost always the product of rheumatic heart disease, the combination of MS and AS can be very confusing to the clinician. When either lesion is severe, it may limit cardiac output, resulting in reduced flow to the other valve, which reduces transvalvular gradient, leading to underestimation of lesion severity. Echocardiography and invasive hemodynamics are usually necessary to fully assess the severity of each lesion and to decide on appropriate intervention. 11. PROSTHETIC VALVES 11.1. Evaluation and Selection of Prosthetic Valves 11.1.1. Diagnosis and Follow-Up of Prosthetic Valves Recommendations for Diagnosis and Follow-Up of Prosthetic Valves Referenced studies that support the recommendations are summarized in Online Data Supplement 34. COR LOE Recommendations In patients with a surgical or transcatheter prosthetic valve and in patients who have had valve repair, an initial postprocedural TTE study is recommended for evaluation of valve hemodynamics and ventricular function.1 4 In patients with a prosthetic valve or prior valve repair and a change in clinical symptoms or signs suggesting valve dysfunction, repeat TTE is recommended. In patients with a prosthetic valve replacement or prior valve repair and clinical symptoms or signs that suggest prosthetic valve dysfunction, additional imaging with TEE, gated cardiac CT, or fluoroscopy is recommended, even if TTE does not show valve dysfunction. In patients with a bioprosthetic surgical valve, TTE at 5 and 10 years and then annually after implantation is reasonable, even in the absence of a change in clinical status. In patients with a bioprosthetic TAVI, TTE annually is reasonable. Table 21. 