Intraoperative Coregistration of 3D Transesophageal Echocardiography with Live Fluoroscopy Facilitates Transcatheter Mitral Valve-in-Valve Implantation in Cases of Invisible Surgical Valves

Objectives: Transcatheter mitral valve-in-valve implantation (TMViV) has evolved to a viable treatment alternative for high-risk patients with degenerated bioprosthetic mitral valves. Technically the transcatheter valve is positioned using fluoroscopy guidance within the degenerated bioprosthetic to restore physiologic function. Some types of bioprosthetic are fluoroscopically translucent, rendering the target deployment area “invisible.” The aim of this study was to evaluate the feasibility of intra-operative fusion of 3D transesophageal echocardiography (TEE) and live fluoroscopy to facilitate accurate TMViV in cases of invisible bioprosthetic valves.

Methods: We reviewed all TMViV procedures via transapical-route, at our center from July 2013 to July 2018. Patient, procedure, and outcome details were compared between those undergoing a TMViV Implantation into a visible target bioprosthetic valve (group A) to those into an invisible one (group B). Intra-operative image fusion, whereby 3D-TEE und Fluoroscopy were co-registered in the Phillips Echonavigator program using operator-defined landmarks, was used in all group B but not in group A cases. A Wilcoxon rank-sum test or chi-squared tests were used for statistical comparison.

Results: Twenty-nine patients met inclusion criteria. Twenty-two of these were in group A, while seven were in group B. TMViV was successful in all cases in both groups. The patient characteristics, fluoroscopy exposure times and doses were comparable between the groups (Table 1). There were four reoperations. In-group A were two reoperations for bleeding and one for pacemaker implantation. One patient in group B developed valve thrombosis then excessive bleeding following lysis therapy. There were no episodes of valve migration, LVOT obstruction, paravalvular leakage greater than trace, stroke, myocardial infraction, or hospital mortality in either of the groups.

Conclusions: The use of intra-operative 3D TEE and live fluoroscopy image fusion facilitates accurate transcatheter mitral valve-in-valve implantation among patients with a fluoroscopically invisible target-landing zone.

Table 1 Patient, procedure, and outcome comparison between the two groups

	Group A (visible target bioprosthetic valve)	Group B (invisible target bioprosthetic valve)	p-Value
Euro score II (median [IQR])	9.05 [6.70, 15.62]	15.53 [4.96, 29.10]	0.762
STS Prom Score (median [IQR])	5.50 [3.90, 9.40]	8.47 [4.10, 14.00]	0.546
TMViV combined with TAVI	6 (27%)	3 (42%)
Radiation exposure time in minutes (median [IQR])	7.20 [5.89, 12.65]	10.00 [8.48, 13.41]	0.4
Radiation exposure in mGray/cm2 (median [IQR])	5533.50 [3215.50, 11849.02]	3643.90 [1993.15, 25366.50]	0.838
Mean transmitral gradient (Dpmean) at discharge in mm Hg (median [IQR])	5.20 [3.50, 7.22]	7.00 [5.00, 9.65]	0.222

Die Autoren geben an, dass kein Interessenkonflikt besteht.