Invasive haemodynamic characteristics and clinical outcomes of patients presenting with symptomatic severe aortic valve stenosis undergoing transcatheter aortic valve implantation

Abstract

The present thesis is comprised of an introduction followed by eight chapters. The introduction gives an overview of the transcatheter aortic valve implantation (TAVI) procedure and details the patient selection process. Chapter 1 reviews the methods of determining aortic stenosis (AS) heamodynamic severity and the pros and cons of using transthoracic echocardiography versus an invasive evaluation. Severe AS may be divided into three subtypes, namely, 1) high gradient AS, 2) “paradoxical” low-flow, low-gradient severe AS, and 3) low ejection fraction, low-gradient (LEF-LG) severe AS. Chapter 2 assesses the clinical outcomes of patients undergoing TAVI according to this new classification system. Chapter 3 further explores the flow-gradient classification of severe AS as proposed by Dumesnil et al. The majority of patients presenting with symptomatic severe AS have concomitant coronary artery disease (CAD), and the appropriate management of this condi-tion is an important consideration in the overall management of patients presenting with sympto-matic severe AS. Chapter 4 provides a comprehensive overview of the management of concomi-tant CAD among patients presenting with symptomatic severe AS. Chapter 5 and chapter 6 deal with the high-risk subset of patients presenting with LEF-LG severe AS. Patients presenting with the latter condition have a high prevalence of concomitant CAD, and chapter 5 attempts to address the optimal strategy for managing these patients. Patients presenting with LEF-LG severe AS also have a high prevalence of concomitant moderate to severe mitral regurgitation (MR) and chapter 6 assesses the effect of MR on clinical outcomes after TAVI. A new classification for pulmonary hy-pertension was recently proposed and chapter 7 investigates whether this system may be useful for further risk stratification of patients undergoing TAVI. Finally, chapter 8 investigates the impact of B-type natriuretic peptide on short term clinical outcomes after TAVI.