Open Issues in TAVI Part 1
Open Issues in TAVI Part 1
An exponential increase in the use of transcatheter aortic valve implantation (TAVI) in patients with severe aortic stenosis has been witnessed over the recent years. The current article reviews different areas of uncertainty related to patient selection. The use and limitations of risk scores are addressed, followed by an extensive discussion on the value of three-dimensional imaging for prosthesis sizing and the assessment of complex valve anatomy such as degenerated bicuspid valves. The uncertainty about valvular stenosis severity in patients with a mismatch between the transvalvular gradient and the aortic valve area, and how integrated use of echocardiography and computed tomographic imaging may help, is also addressed. Finally, patients referred for TAVI may have concomitant mitral regurgitation and/or coronary artery disease and the management of these patients is discussed.
In 2002, transcatheter aortic valve implantation (TAVI) was introduced as an alternative treatment in patients with severe aortic valve stenosis (AS). Since then several transcatheter valve prostheses have received CE approval including the balloon-expandable Edwards SAPIEN valve prostheses (Edwards SAPIEN; Edwards Lifesciences, Irvine, CA, USA) and its recent device iterations (SAPIEN XT, SAPIEN 3) available for transfemoral and transapical access, the self-expandable CoreValve system (Medtronic, Inc., Minneapolis, MN, USA), the transfemoral self-expanding Portico valve (St Jude Medical. St Paul, MN, USA), the Direct Flow prosthesis (Direct Flow Medical, Inc., Santa Rosa, CA, USA), the Lotus valve (Boston Scientific Corporation, Natick, MA, USA), and the transapical Symetic Acurate (Symetis SA, Ecublens, Switzerland), JenaValve (JenaValve, Munich, Germany), and Medtronic Engager (Medtronic, Inc., Minneapolis, MN, USA). Over the years, a rapid development in prosthetic valves has been witnessed, with the introduction of various prosthetic designs and sizes. The crossing profile of the delivery sheaths has been improved and the sizes have been reduced. These developments have significantly improved procedural success rates and outcome, with a reduction in complications.
It is estimated that >100 000 TAVIs have been performed between 2002 and 2013. It has also become evident that many areas of uncertainty exist around TAVI, which are addressed in the current reviews. In the first part, issues around patient selection are discussed, such as the need for improved risk scores, and the value of sophisticated, three-dimensional non-invasive imaging for prosthesis sizing. Uncertainty also exists on optimal visualization of native valve anatomy in bicuspid valves, and the quantification of stenosis severity in low-flow low-gradient AS. Another issue of controversy is the outcome after TAVI in patients with pre-existent left ventricular (LV) dysfunction. Finally, concomitant mitral regurgitation (MR) and coronary artery disease (CAD) are frequently encountered and the need and timing for therapeutic intervention is unclear as well as their impact on prognosis.
The available literature on these issues will be reviewed and the specific areas, where conclusive data are lacking will be summarized. Part 2 will focus on procedural issues and outcomes.
Abstract and Introduction
Abstract
An exponential increase in the use of transcatheter aortic valve implantation (TAVI) in patients with severe aortic stenosis has been witnessed over the recent years. The current article reviews different areas of uncertainty related to patient selection. The use and limitations of risk scores are addressed, followed by an extensive discussion on the value of three-dimensional imaging for prosthesis sizing and the assessment of complex valve anatomy such as degenerated bicuspid valves. The uncertainty about valvular stenosis severity in patients with a mismatch between the transvalvular gradient and the aortic valve area, and how integrated use of echocardiography and computed tomographic imaging may help, is also addressed. Finally, patients referred for TAVI may have concomitant mitral regurgitation and/or coronary artery disease and the management of these patients is discussed.
Introduction
In 2002, transcatheter aortic valve implantation (TAVI) was introduced as an alternative treatment in patients with severe aortic valve stenosis (AS). Since then several transcatheter valve prostheses have received CE approval including the balloon-expandable Edwards SAPIEN valve prostheses (Edwards SAPIEN; Edwards Lifesciences, Irvine, CA, USA) and its recent device iterations (SAPIEN XT, SAPIEN 3) available for transfemoral and transapical access, the self-expandable CoreValve system (Medtronic, Inc., Minneapolis, MN, USA), the transfemoral self-expanding Portico valve (St Jude Medical. St Paul, MN, USA), the Direct Flow prosthesis (Direct Flow Medical, Inc., Santa Rosa, CA, USA), the Lotus valve (Boston Scientific Corporation, Natick, MA, USA), and the transapical Symetic Acurate (Symetis SA, Ecublens, Switzerland), JenaValve (JenaValve, Munich, Germany), and Medtronic Engager (Medtronic, Inc., Minneapolis, MN, USA). Over the years, a rapid development in prosthetic valves has been witnessed, with the introduction of various prosthetic designs and sizes. The crossing profile of the delivery sheaths has been improved and the sizes have been reduced. These developments have significantly improved procedural success rates and outcome, with a reduction in complications.
It is estimated that >100 000 TAVIs have been performed between 2002 and 2013. It has also become evident that many areas of uncertainty exist around TAVI, which are addressed in the current reviews. In the first part, issues around patient selection are discussed, such as the need for improved risk scores, and the value of sophisticated, three-dimensional non-invasive imaging for prosthesis sizing. Uncertainty also exists on optimal visualization of native valve anatomy in bicuspid valves, and the quantification of stenosis severity in low-flow low-gradient AS. Another issue of controversy is the outcome after TAVI in patients with pre-existent left ventricular (LV) dysfunction. Finally, concomitant mitral regurgitation (MR) and coronary artery disease (CAD) are frequently encountered and the need and timing for therapeutic intervention is unclear as well as their impact on prognosis.
The available literature on these issues will be reviewed and the specific areas, where conclusive data are lacking will be summarized. Part 2 will focus on procedural issues and outcomes.
