Replacing the valve, restoring the flow: Effects of transcatheter aortic valve implantation

When conventional surgery is not an option due to high surgical risk, transcatheter aortic valve implantation (TAVI) is a firmly established alternative and an effective and safe treatment option in this patient population. This thesis focuses on treatment of aortic valve stenosis by TAVI. The aim is to provide insight in the pathophysiology of aortic stenosis and the effects of TAVI on clinical outcomes of patients, as well as the hemodynamic effect on left ventricular and coronary physiology. The preoperative considerations are discussed. The intraoperative considerations of transcatheter aortic valve implantation are evaluated, where safety and feasibility of TAVI using exclusively local analgesia and fluoroscopic guidance, is demonstrated. The predictors and prognostic value of myocardial injury during transcatheter aortic valve implantation are described. More insight is provided on the patholophysiology of aortic valve stenosis and the immediate effect of transcatheter aortic valve implantation on the left ventricular and coronary hemodynamics. TAVI immediately improves coronary hemodynamics, and partly relieves a pathological increase in minimal microvascular resistance. As assessed by invasive intraventricular PV loop measurements, relief of AS by TAVI immediately reduces afterload and markedly improves LV systolic performance. The diastolic function remains unaltered immediately after TAVI due to unaltered intrinsic properties by LV hypertrophy. The final part of the thesis discusses the postoperative considerations and future considerations. Finally, an overview of the current status of development of TAVI-prostheses is provided, describing the technical features and applicability of each device and the clinical data available