Structural Transcatheter Aortic Valve Implantation
Avoiding Coronary Occlusion and Root Rupture in TAVI – The Role of Pre-procedural Imaging and Prosthesis Selection Marco Barbanti Ferrarotto Hospital, University of Catania, Catania, Italy
Abstract Coronary occlusion and rupture of the aortic root or annulus remain two major concerns of transcatheter aortic valve implantation technique. Despite their relatively low frequency they raised the interest of the scientific community as they carry an extremely poor prognosis. Prosthesis type and size selection is part of the patient selection process that allows the operator to prevent these complications. In this article, the techniques used either during pre-TAVI screening or during the procedure itself to avoid coronary occlusion and aortic rupture will be discussed.
Keywords TAVI, complications, coronary occlusion, bailout PCI, aortic rupture Disclosure: The author has no conflicts of interest to declare. Received: 25 March 2015 Accepted: 22 April 2015 Citation: Interventional Cardiology Review, 2015;10(2):94–7 Correspondence: Marco Barbanti, Division of Cardiology–Ferrarotto Hospital, University of Catania, Italy. E: mbarbanti83@gmail.com
Transcatheter aortic valve implantation (TAVI) is an effective treatment for patients with severe aortic valve stenosis and high operative risk.1 Despite its widespread adoption across the world, this procedure is still associated with several complications.2 Many of these, because their relatively high frequency (conduction disturbances, vascular complications, cerebrovascular events, paravalvular regurgitation, etc.), have been a field of deeper research aimed at defining potential predictive factors, clinical sequelae and procedural management.3–5 Nonetheless, TAVI has also been associated with very rare but life-threatening complications, such as coronary ostia obstruction and aortic rupture.6,7 Because of their extremely poor prognosis, prevention of these complications is of particular interest. In this scenario, prosthesis type and size selection is part of the patient selection process that allows the operator to prevent these complications and finally determine procedural outcome.7,8 In this review, the techniques used either during pre-TAVI screening or during the procedure itself to avoid coronary occlusion and aortic rupture will be discussed
Coronary Occlusion The occurrence of coronary occlusion after TAVI was first described in 2006.9 In contemporary series its incidence has usually been less than 1 %, ranging from 0 % to 4.1 %.2 A recent systematic review showed that reported cases of coronary obstruction following TAVI occurred more frequently in women and patients receiving a balloon-expandable transcatheter heart valve (THV) (SAPIEN, Edwards Lifesciences, Irvine, CA, US), and the left coronary artery was the most commonly involved.6 In native aortic valves, coronary ostia obstruction is related to two main procedural factors: 1) In the vast majority of cases it occurs due
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to the displacement of a bulky calcified native valve over a coronary ostium; 2) the second option is more hypothetical: it occurs following an obstruction by a portion of the THV frame or the sealing cuff placed directly over a coronary ostium; however, no cases of coronary obstruction related to the struts of the THV frame or to the cuff/ leaflets of the transcatheter valve itself have been reported to date. In both cases there are some anatomic features (narrow sinus of Valsalva, bulky leaflet calcifications, low-lying coronary ostia) that have been involved in its pathogenesis (see Figure 1). In a multicentre study enrolling 44 patients who suffered symptomatic coronary occlusion among a large series of 6,688 TAVIs, Ribeiro and colleagues demonstrated that lower-lying coronary ostium (<12 mm) and shallow sinuses of Valsalva (<30 mm) were the strongest anatomic factors associated with coronary obstruction. 8 Nevertheless, the risk of coronary occlusion remains difficult to assess, and no definite criteria exist to exclude patients deemed at high risk. However, this study suggests that greater caution should be applied when we are dealing with patients candidate to TAVI having such anatomical features. A careful evaluation by means of multimodality imaging can help to highline the bulkiness of the native cusps, the height of the coronary ostia and the dimensions of the sinus of Valsalva. In daily clinical practice, these evaluations can be made by using multidetector computed tomography (MDCT), which allows for a granular 3D reconstruction of the aortic root, providing extremely reliable assessment of dimensions and calcium distribution (see Figure 2).10,11 3D echocardiogram is also an important tool for aortic root measurements and for pre-procedural assessment of the coronary ostia, but it is limited by its inability of characterise aortic root calcifications.12
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