Demystifying Complex Coronary Hemodynamics in Patients Undergoing Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement (TAVR) has revolutionized the treatment of patients with severe aortic stenosis who are at high risk for traditional surgical intervention.1,2 As the technology matures and experience grows, the applicability of TAVR to lower risk populations is likely and is already being explored.3 These patients often present with chest pain or exertional dyspnoea in the context of varying degrees of coronary artery disease. An understanding of how the aortic valve affects coronary hemodynamics is becoming increasingly clinically relevant in determining how to manage this coexisting coronary disease.See Article by Wiegerinck et al Creating a model of aortic stenosis is challenging. The pressure loading of the ventricle and coronary arteries varies according to the location of the stenosis. Stenosis at the level of the aortic valve is anatomically below coronary artery inflow; this results in increased afterload of the left ventricle but reduces coronary perfusion pressure. Relief of the stenosis therefore results in an acute reduction in left ventricular end-diastolic pressure, and in most cases, it results in an increase in coronary perfusion. This differs from the traditional systemic hypertension model often generated experimentally in animal models in which a restrictive band is placed around the aorta.4 In such cases, the stenosis is positioned in the aorta distal to coronary artery inflow; this results in an increase in both left ventricular end-diastolic pressure and coronary perfusion. After removal of the aortic band, both left ventricular end-diastolic pressure and coronary perfusion fall; as a result, the …