Transcatheter aortic valve insertion (TAVI): a review

Abstract

The introduction of transcatheter aortic valve insertion (TAVI) has transformed the care provided for patients with severe aortic stenosis. The uptake of this procedure is increasing rapidly, and clinicians from all disciplines are likely to increasingly encounter patients being assessed for or having undergone this intervention. Successful TAVI heavily relies on careful and comprehensive imaging assessment, before, during and after the procedure, using a range of modalities. This review outlines the background and development of TAVI, describes the nature of the procedure and considers the contribution of imaging techniques, both to successful intervention and to potential complications.

Figures

Figure 1.

Insertion of an Edwards valve via the apical approach. (a) Collapsed stent over a guidewire via the apical introducer (AI). A pigtail catheter (PC) can also be seen in the aortic root, in addition to a right ventricular, temporary pacing wire (TPW) and a transoesophageal echo (TOE) probe. (b) The expanded prosthesis in place.

Figure 2.

Pre-assessment of peripheral arterial access with CT can identify where the vascular tree is too narrow (a), too tortuous (b) or otherwise undesirable [(c) demonstrating an infrarenal aortic aneurysm].

Figure 3.

Sizing the aortic valve annulus. (a) From the axial views, identify the centre of the mitral valve, through which an oblique plane is generated (solid line), perpendicular to a line from the valve to the apex (broken line). This results in (b) an oblique view through the aortic valve and a second oblique view is then created, perpendicular to the valve plane, along the centre of the aortic root (solid line). (c) This plane effectively provides a 3-chamber view comprising the left atrium, left ventricle and left ventricular outflow tract. A final oblique line is drawn through the hinge point of the non-coronary cusp, perpendicular to the aortic root (solid line), to give (d) a cross-section through the valve. The oblique plane should be rotated (c, white arrow) until (e) all three valve cusps appear equally visible. The plane can be adjusted longitudinally (c, black arrow) until (f) the valve is just in view, which provides the location for annular measurement.

Figure 4.

The right coronary artery in this patient was

Figure 5.

This prosthesis migrated into the left ventricular cavity (a) and had to be surgically removed via the apex (b), unfortunately leaving a traumatic ventricular septal defect (c, arrow).

Figure 6.

A Medtronic CoreValve® (Medtronic, Inc., Minneapolis, MN) in the aortic position. The metallic stent framework can be seen extending into the aortic root. There is a St Jude metallic mitral valve (St Jude Medical, St Paul, MN) replacement adjacent to this, highlighting the close proximity of the two valves. Excessive caudal positioning of the transcatheter aortic valve insertion prosthesis therefore risks impinging on the mitral valve.

Figure 7.

Contrast extravasation highlighting rupture at the aortic root (arrow).

Figure 8.

A traumatic ventricular septal defect following repair with an occluder device (arrow).

Figure 9.

Ungated CT pulmonary angiogram demonstrating a distinctive Edwards SAPIEN (Edwards Lifesciences, Irvine, CA) transcatheter aortic valve insertion prosthesis.