1

Introduction

Transcatheter aortic valve implantation (TAVI) has emerged as a new alternative technique to standard surgical aortic valve replacement for patients with severe aortic stenosis at high operative risk. Complications associated with this transcatheter procedure differ from complications occurring after surgical aortic valve replacement. The self-expandable Corevalve prosthesis exposes the patient to specific procedural complications that have been shown to be strongly associated with higher early mortality . Among them, Corevalve dislocation as defined by a partially or complete valve deployment outside the native aortic annulus has been reported to occur in about 10% of the cases . Most of the time, when the valve is partially expanded and still anchored and crimped in the housing sheath, it is possible to retrieve it by pulling back the catheter delivery system (CDS) en bloc with the semiexpanded valve through the 18-Fr introducer sheath that is stiff enough to allow the valve retrieval out of the body . This is a standard maneuver that we performed successfully several times in our center when the femoral approach is used. We report here the case of a patient who underwent TAVI and who presented an unusual serious complication after Corevalve dislocation during the attempt to retrieve the partially expanded valve through a subclavian introducer sheath.

2

Case report

An 87-year-old man was referred to our institution for management of severe symptomatic aortic stenosis. The patient experienced shortness of breath (New York Heart Association functional class III). His medical record showed history of previous coronary artery bypass grafting with left internal mammary artery (LIMA) to left anterior descending artery (LAD) performed in 1998 and a peripheral vascular disease. Logistic Euroscore was of 23.8%. He was also obese and had hypertension. Transthoracic echocardiography showed severe calcified aortic stenosis with a peak gradient of 81 mmHg, mean gradient of 53 mmHg, valve area of 0.35cm ² /m ² , aortic annulus diameter of 24 mm, and a left-ventricular ejection fraction of 50% with an akinetic inferior wall. Coronary angiogram showed an occlusion of the mid-LAD with a patent LIMA graft to distal LAD, an occlusion of the proximal circumflex coronary artery, and a nonsignificant disease on the right coronary artery. Computed tomography scanner of the aorta and its branches showed severe calcifications and tortuosities of iliac femoral arteries. The left subclavian artery presented a linear course, no significant calcification, and a minimal luminal diameter ≥7.5 mm ( Fig. 1 A and B). Considered at high operative risk of standard open-heart surgery by the heart team, the patient was referred for TAVI. Despite the patent LIMA graft, the left subclavian artery access was felt to be the most reasonable approach to use.

(A & B) Computed tomographic angiography of left subclavian artery. (C) Partially deployed Corevalve (Cor) displaced above the aortic valve annulus [conical tip (1)]. (D) Partially expanded Cor and the CT stuck in the subclavian sheath. (E) Expulsion of both the Cor and the CT into the ascending aorta with the sheath dilator (Dil). (F) CT stuck into the commune femoral artery. (G) CT and housing sheath (HS) of the catheter delivery system at the end of the procedure. We can observe an elongation of the plastic component joining the CT and the delivery anchors. (H) Dislocated Corevalve in the ascending aorta and new prothesis in correct annular position.

Initial valvuloplasty was performed using a 22-mm diameter Nucleus (NuMed) balloon under rapid pacing. The deployment procedure and the release of the Corevalve were initiated. Unfortunately, as soon as the inflow part of the prosthetic valve reached the adjacent left ventricular outflow track wall, the partially expanded valve was dislodged superiorly above the aortic valve annulus at its left coronary cusp side ( Fig. 1 C). The decision was made to perform a retrieval of the valve, which was still partially attached and crimped in the housing sheath. At first, the valve and the housing sheath at the distal part of the catheter delivery system (CDS) were pulled back en bloc into the 18-Fr introducer subclavian sheath (Cook) that was positioned in the upper part of the ascending aorta. Suddenly, the Corevalve came off the CDS at the level of the delivery anchors. We did not initially realize that, and we continued to pull the CDS back. As a consequence, a fracture of the distal part of the CDS occurred just before the distal conical tip (CT) that was trapped in the subclavian sheath by the Corevalve frame still partially crimped. At this time, the partially expanded valve and the CT were stuck in the subclavian sheath ( Fig. 1 D). The decision was made to use the sheath dilator to push the Corevalve in the ascending aorta. Subsequently, the CT was expulsed into the aorta ( Fig. 1 E). Fortunately, the CT course ended in the common femoral artery, and it was possible to retrieve it via a simple surgical access ( Fig. 1 F and G). A second Corevalve was implanted through the first one positioned in the ascending aorta using the same route ( Fig. 1 H). Control echocardiography showed a good aortic prosthetic valve performance (peak gradient of 15 mmHg, mean gradient of 8 mmHg). Postoperative in-hospital outcome was favorable with especially no neurological clinical event, and the patient was discharged on day 10 including 2 days in the intensive care unit. At 1 month, he described a great symptom improvement.