Cardiac Imaging in Clinical Trials of Intervention in Aortic Valve Stenosis

Cardiac imaging and in particular transthoracic echocardiography and computed tomography play a major role in the selection of the patients for surgical or transcatheter aortic valve replacement, for the assessment or procedural success and early prosthetic valve hemodynamics following aortic valve replacement, and for the evaluation and follow-up of the prosthetic valve structure and function in the longer-term, which is key to demonstrate the valve durability. The purpose of this review article is thus to present the role of cardiac imaging, and particularly transthoracic echocardiography and computed tomography, in: (1) patient selection for intervention; (2) assessment of procedural and device success, and of intended performance of the valve; and (3) assessment of the long-term success, valve durability, and prognosis, for clinical trials of intervention in patients with aortic stenosis. Transthoracic echocardiography is the primary imaging modality to detect and stage bioprosthetic valve dysfunction. However, multimodality imaging, including transesophageal echocardiography and computed tomography, is often necessary to determine the cause of bioprosthetic valve dysfunction and make the differential diagnosis between prosthesis-patient mismatch, structural valve deterioration, thrombosis, pannus, or endocarditis. The clinical trials in the field of structural heart disease, and particularly in the field of aortic valve intervention, include imaging end points as part of the primary or key secondary end points. Standardized methods and definitions should be applied to adjudicate these imaging end points, and ideally, these trial end points should be analyzed by independent imaging core labs.