2023 年 5 巻 12 号 p. 463-464
An 88-year-old man with severe degenerative mitral regurgitation (MR) was scheduled for MitraClip therapy because of his prohibitive surgical risks [STS score, 19.9%]. Transesophageal echocardiography (TEE) revealed P3 prolapse and increased echogenicity in the A3 leaflet body (Figure A,B), with a mitral valve (MV) area of 4.3 cm2. He underwent ECG-gated 4-dimensional computed tomography (4D-CT; GE Healthcare, USA) for evaluation of the characteristics of the MV apparatus. The CT images obtained mid-systole were analyzed with Ziostation2 (Ziosoft, Japan) and clearly demonstrated bar-shaped calcification traversing A3 and the precise location of the chordae tendineae (Figure C; Supplementary Movie 1). Thus, we grasped P3 and the anterior leaflet facing P3 with a clip rotated counterclockwise by 10° to avoid interference with the calcification of A3. The NTW clip (Abbott Vascular, USA) initially became entangled with the commissural chords, but we successfully deployed the clip in the target leaflets. To avert the risk of single-leaflet device attachment of the first clip, we added a second NT clip more medial to the first clip, taking care to avoid grasping the bar-shaped calcification (Figure D). MR was markedly reduced with hemodynamic improvement. On postoperative 4D-CT, both clips had been successfully positioned without grasping the A3 calcification (Figure E,F; Supplementary Movie 2). The patient was asymptomatic on discharge.
Transesophageal echography (TEE) images of (A) P3 prolapse (*) and (B) long-axis view of P3 prolapse and A3 calcification. (C) 4D-computed tomography (CT) demonstrating P3 prolapse (*) and A3 calcification. Multiplanar reconstruction along the lines (a) without and (b) with A3 calcification. (D) TEE showing the relationship between the calcification and clips. (E) Postprocedural 4D-CT demonstrating successful clip implantation avoiding the calcification. (F) Multiplanar reconstruction showing the second clip. AML, anterior mitral leaflet.
This case demonstrated the novel utility of ECG-gated 4D-CT in assessing the MV apparatus. Severe leaflet calcification in the grasping zone is still considered a challenging feature in patients undergoing MitraClip therapy. In such cases, obtaining preprocedural information on MV calcification is crucial, because TEE has limited specificity for identifying calcification. Preprocedural 4D-CT evaluation of MV calcification optimally guided clip positioning, helping avert catastrophic adverse events, including leaflet tear. In an ever-aging society with a rising incidence of severe MV calcifications, combining TEE and ECG-gated 4D-CT can ensure optimal treatment.
Supplementary Movie 1. Images of the mitral valve acquired with transesophageal echography (TEE) and ECG-gated CT before MitraClip procedure.
Supplementary Movie 2. Images on TEE during MitraClip procedure and ECG-gated CT after clip implantation.
Please find supplementary file(s);
https://doi.org/10.1253/circrep.CR-23-0089
