Author + information
- Ryoji Iida, MD,
- Robert C. Welsh, MD,
- Steven R. Meyer, MD, PhD,
- Benjamin D. Tyrrell, MD,
- Dylan A. Taylor, MD and
- Miriam Shanks, MD⁎ ()
- ↵⁎Division of Cardiology, University of Alberta Hospital, 8440-112 Street, 2C2 Walter Mackenzie Health Sciences Centre, Edmonton, Alberta, T6G 2B7 Canada
Transcatheter aortic valve implantation (TAVI) has been recognized as an alternative treatment for high-risk surgical patients with symptomatic severe aortic stenosis (AS). Valve migration is a potentially life-threatening complication of TAVI that usually occurs during implantation. Late (>24 h) (1) migration may result in catastrophic complications like cardiogenic shock (1) or heart failure (2). We recently encountered a case of a valve migration into the left ventricular outflow tract (LVOT) identified on a routine 24-h follow-up echocardiogram in an asymptomatic patient.
A 77-year-old man with symptomatic severe AS and high risk for surgical replacement (European System for Cardiac Operative Risk Evaluation score 20%; Society of Thoracic Surgeons score 17%) underwent TAVI. Baseline echocardiogram revealed a calcified trileaflet aortic valve (AV), AV area 0.87 cm2, mean pressure gradient 27 mm Hg, and LV ejection fraction 30%. The patient underwent TAVI in standard fashion with transfemoral approach. Intraprocedural transesophageal echocardiogram (TEE) confirmed the aortic annulus diameter of 23 mm. As such, a 26 mm balloon-expandable bioprosthesis (Edwards-SAPIEN, Edwards Lifesciences, Irvine, California) was selected. After the native AV balloon pre-dilation, the TAVI valve was advanced to the annulus using fluoroscopic and TEE guidance and deployed under rapid pacing. Post-deployment, aortogram TEE (Fig. 1A,Online Video 1) and TEE (Fig. 1B, Online Video 2) confirmed optimal valve position. The mean pressure gradient was 9 mm Hg. There was a single jet of moderate eccentric periprosthetic regurgitation (Online Video 3). Considering the patient's hemodynamic stability, no evidence of inadequate valve deployment, and a small risk of device displacement or development of central regurgitation with redilation, no further intervention was undertaken.
Transthoracic echocardiogram (TTE) repeated 24 h after TAVI revealed an increased prosthetic mean pressure gradient (22 mm Hg). Importantly, partially mobile thickened native leaflets were seen overlying the prosthetic stent suggesting TAVI valve migration into LVOT (Fig. 1C, Online Video 4). In addition to mild-to-moderate periprosthetic regurgitation, severe central regurgitation ceasing within LVOT was demonstrated (Fig. 1D, Online Video 5). Urgent TEE confirmed valve migration into LVOT resulting in a simultaneous functioning of the native and bioprosthetic valves (Online Video 6). Full closure of the native valve leaflets was restricted by the prosthetic stent resulting in severe central regurgitation stopping at the competent bioprosthetic leaflets. An urgent valve-in-valve TAVI was planned but repeat TEE demonstrated further valve migration into LVOT that precluded safe implantation of the second overlapping prosthesis. The patient underwent an emergent open-heart surgery during which the TAVI valve was found sitting in LVOT in an unstable position. The native valve leaflets had 3 relatively flexible cusps with moderate calcification (Fig. 1E). The aortic annulus had only trivial amount of calcium. The AV was replaced with 23-mm Perimount Magna (Edwards Lifesciences) tissue valve. The patient tolerated the surgery well.
Valve dislodgment may occur in patients with less-than-severe AV and root calcification that may be insufficient for anchoring the prosthesis (1,2), which was likely the case in our patient. Other potential causes include stent malposition (3,4) and selection of an undersized valve (5). In the present case, the correct 26-mm valve was selected based on 23-mm annulus, and its optimal position was confirmed with aortogram and TEE. Forces from the periprosthetic and central AV regurgitation, and from the residual overhanging native AV leaflets (2) likely contributed to the progression of valve migration.
This case demonstrates that routine 24-h follow-up echocardiography is essential to confirm correct TAVI valve position and function in order to prevent adverse consequences of delayed mechanical complications. In addition, it demonstrates that TAVI should be used with caution in patients with less-than-severe AV calcification.
For supplementary videos and their legends, please see the online version of this article.
Please note: Dr. Meyer is his site's local investigator for Boehringer Ingelheim's ReAlign trial investigating the use dabigatran in the anticoagulation of mechanical heart valves. He personally receives no money for this trial. His site does receive money to support their research coordinator for this trial. Dr. Shanks serves on the advisory board for Servier Canada and has received honorarium from Astra Zeneca. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
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