Cardiac Imaging
Usefulness of Multidetector Computed Tomography Imaging Before Percutaneous Prosthetic Aortic Valve Implantation
Maxime Teisseire, MS,1 Jérôme Caudron, MD2 and Jean-Nicolas Dacher, MD, PhD3
1. Advanced Application Specialist, Department of Diagnostic Imaging, Rouen University Hospital; 2. Fellow, Department of Diagnostic Imaging, Rouen University Hospital; 3. Professor of Radiology, Rouen University, and Head, Department of Diagnostic Imaging, Rouen University Hospital
Abstract
Percutaneous implantation of an aortic valve has become a promising alternative treatment for patients with severe symptomatic aortic stenosis in whom conventional surgical treatment is contraindicated. A transfemoral or transapical delivery route can be chosen depending on the quality of vascular access and the type and size of prosthesis used. This article will mainly focus on the retrograde transfemoral approach, a technique with a high procedural success rate that is growing in popularity. Collaboration between radiologists and cardiologists is vital for a good outcome, and is mainly based on multidetector computed tomography (MDCT), which has quickly assumed a leading role in pre-implantation planning for inoperable severe aortic stenoses. The contribution of MDCT post-implantation is still under evaluation, but also seems promising. This article will discuss procedural techniques and clinical aspects of MDCT examination before and after percutaneous aortic valve implantation using the arterial transfemoral approach.
Keywords Aortic stenosis, percutaneous aortic valve implantation, multidetector computed tomography, spectral imaging
Disclosure: Maxime Teisseire, MS, is a consultant for General Electric Healthcare. The remaining authors have no conflicts of interest to declare. Received: July 21, 2010 Accepted: September 14, 2010 Citation: US Radiology, 2011;3:32–5 Correspondence: Jean-Nicolas Dacher, MD, PhD, Department of Radiology, University Hospital of Rouen, 1 rue de Germont, 76031 Rouen Cedex, France. E:
Jean-Nicolas.Dacher@chu-rouen.fr
In patients with severe aortic stenosis (aortic valve area <1 cm2 or <0.6 cm2/m2) and high surgical risk (hemodynamic instability or significant comorbidities), surgical aortic valve replacement is often rejected and, unfortunately, balloon valvuloplasty cannot provide a sustained improvement. Percutaneous heart valve (PHV) implantation is an excellent alternative treatment in such cases. The first successful human PHV implantation was performed in April 2002 by Cribier’s group at Rouen University Hospital in France, via the antegrade (venous) transseptal approach.1
Because of the complexity of the antegrade approach, several changes were introduced to implantation protocols.
The transapical approach is the most recently developed technique for transcatheter aortic valve replacement. This procedure involves a limited left lateral thoracotomy and requires a direct cardiac puncture and sheath insertion into the left ventricle. The transfemoral retrograde procedure is performed under local anesthesia and mild sedation. The common femoral artery is first exposed by the surgeon, then catheterized. After retrograde catheterization of the aortic valve balloon, pre-dilation of the aortic valve is performed. The femoral artery is then pre-dilated with a series of dilators of increasing size to facilitate the entry of the sheath. The PHV is advanced over the extra-stiff guidewire, placed within the native
Subsequently, the arterial transfemoral and transapical delivery routes were developed.2,3
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valve, and deployed using rapid ventricular pacing.4
The device used at
our institution is an Edwards SAPIEN transcatheter aortic prosthesis (Edwards Lifescience, Irvine, CA, US) mounted on a balloon-expandable stainless steel stent. The trileaflet bovine pericardial prosthesis is attached to the stent and coated with an anticalcification treatment. The stent has a polyethylene terephthalate fabric skirt that reduces perivalvular leaks (see Figure 1). Owing to its high procedural success rate and the simplicity of the delivery technique, since 2005, the transfemoral antegrade approach has become the most commonly used procedure.4
This article will therefore examine this technique only.
Accurate assessment of the iliofemoral arteries prior to valve implantation is mandatory with this technique. Multidetector-row computed tomography (MDCT) is helpful since it offers detailed imaging of calcifications of the arterial wall and depicts vessel tortuosity in any plane with high spatial resolution. This article will describe the role of MDCT in planning and performing PHV implantation. Its contribution after implantation is still under evaluation.
Multidetector Computed Tomography Before Percutaneous Heart Valve Implantation CT works as a complement to echocardiography and conventional angiography. At our institution, the examination comprises two
© TOUCH BRIEFINGS 2011
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