Prognostic Implications of Asymmetric Morphology in Transcatheter Aortic Valve Implantation: a Case Report Implicaciones pronósticas de la morfologı́a asimétrica en la implantación de prótesis aórticas transcatéter: a propósito de un caso

Transcatheter implantation of aortic valve prostheses is being performed with increasing frequency in patients with severe symptomatic aortic stenosis who are at high surgical risk. Either a transfemoral or a transapical approach is employed. Complications related to the procedure are relatively uncommon, but they provide information that is very useful for broadening our knowledge of the pathophysiology of prosthesis dysfunction. A 76-year-old man with severe aortic stenosis underwent transcatheter aortic valve implantation because of high surgical risk due to ischemic heart disease and severe chronic obstructive of a Perimount bioprosthesis (Edwards Lifesciences; Irvine, California, USA). The patient died of cardiogenic shock during the postoperative period. Visual inspection of the explanted SAPIEN valve showed an elliptical morphology with a major diameter of 27 mm and a minor diameter of 20 mm, measurements that agree with those made by means of TEE during the procedure (Fig. 2). Moreover, as documented with TEE, one of the valves was abnormally taut and elongated, with limited mobility. The Edwards-SAPIEN valve is a prosthesis made of bovine pericardium mounted on an expandable stent that is placed in subcoronary position. Nine years after the first case in humans, favorable results have been reported for both the transfemoral and the transapical approach. The complete and symmetric expansion of the prosthesis in the aortic annulus is very important for its normal function and the aim should be to achieve this in every case. In fact, when the valve has a circular aspect, a success rate of 98% can be expected, whereas an oval morphology is associated with suboptimal function and durability. In our case, the massive presence of eccentric calcium in the left coronary valve of the native valve presumably provoked abnormal pulmonary disease. Intraoperative transesophageal echocardiogram (TEE) performed prior to the procedure revealed a severely calcified aortic valve, especially left coronary (Thebesian) valve; the ejection fraction was 42%. Balloon valvuloplasty was carried out, followed by implantation of a 26-mm SAPIEN valve (Edwards Lifesciences; Irvine, California, USA), performed without complications. Immediately after inflation, TEE confirmed that the aortic prosthesis was well positioned, with adequate valve mobility. However, probably due to the severe eccentric calcification, the prosthesis had an asymmetric morphology, with an oval shape and abnormal stretching of the valve, which was oriented along the major axis (Fig. 1). Despite this appearance, the results of the procedure were considered to be satisfactory because the prosthesis appeared to be functioning normally, with mild central and minimal paravalvular regurgitation. Initially, the patient progressed well and was extubated on the first day; however, the next day he developed acute pulmonary edema, with rapid clinical deterioration. An emergency echocardiogram revealed severe aortic regurgitation, and the patient underwent an emergency intervention involving extracorporeal surgery with implantation