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. 2019 Nov;158(5):1332-1340.
doi: 10.1016/j.jtcvs.2019.02.120. Epub 2019 Mar 21.

Optically-guided instrument for transapical beating-heart delivery of artificial mitral chordae tendineae

Zurab Machaidze  1 , Margherita Mencattelli  1 , Gustavo Arnal  1 , Karl Price  1 , Fei-Yi Wu  2 , Viktoria Weixler  1 , David W Brown  3 , John E Mayer Jr  1 , Pierre E Dupont  4
Affiliations

Optically-guided instrument for transapical beating-heart delivery of artificial mitral chordae tendineae

Zurab Machaidze et al. J Thorac Cardiovasc Surg. 2019 Nov.

Abstract

Objective: We sought to develop an instrument that would enable the delivery of artificial chordae tendineae (ACT) using optical visualization of the leaflet inside the beating heart.

Methods: A delivery instrument was developed together with an ACT anchor system. The instrument incorporates an optically clear silicone grasping surface in which are embedded a camera and LED for direct leaflet visualization during localization, grasping, and chordal delivery. ACTs, comprised of T-shaped anchors and an expanded polytetrafluoroethylene chordae, were fabricated to enable testing in a porcine model. Ex vivo experiments were used to measure the anchor tear-out force from the mitral leaflets. In vivo experiments were performed in which the mitral leaflets were accessed transapically using only optical guidance and ACTs were deployed in the posterior and anterior leaflets (P2 and A2 segments).

Results: In 5 porcine ex vivo experiments, the mean force required to tear the anchors from the leaflets was 3.8 ± 1.2 N. In 5 porcine in vivo nonsurvival procedures, 14 ACTs were successfully placed in the leaflets (9 in P2 and 5 in A2). ACT implantation took an average of 3.22 ± 0.83 minutes from entry to exit through the apex.

Conclusions: Optical visualization of the mitral leaflet during chordal placement is feasible and provides direct feedback to the operator throughout the deployment sequence. This enables visual confirmation of the targeted leaflet location, distance from the free edge, and successful deployment of the chordal anchor. Further studies are needed to refine and assess the device for clinical use.

Keywords: artificial chordae; mitral prolapse; optical imaging; transapical.

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Figures

Figure 1.
Figure 1.
Optically-guided artificial chordae delivery instrument. Video camera and LED embedded in optical finger provide clinician with real-time view of optical finger surface. Delivery channel running through optical finger can be seen in images. A. With fingers closed during instrument navigation, the operator can view what is touching the instrument tip, e.g., blood or leaflet tissue as shown on the right. B. Optical finger slides with respect to ring-shaped opposing finger to enable leaflet grasping. Leaflet image from optical finger shows tissue quality and distance from delivery channel to leaflet free edge. Artificial Chordae Tendineae (ACT) delivery system can be seen inside delivery channel.
Figure 2.
Figure 2.
Artificial Chordae Tendineae (ACT) delivery system. A. Cylindrical anchor attached to expanded polytetrafluoroethylene (ePTFE) chordae. B. Anchor slides over stylet and rests on delivery cannula. Assembled system is inserted through delivery channel of instrument.
Figure 3.
Figure 3.
Artificial Chordae Tendineae (ACT) delivery to the mitral valve. A. Instrument is advanced to the valve with fingers closed. B. Leaflet is grasped. C. ACT delivery sytem is extended through delivery channel so that stylet pierces leaflet. D. Stylet and delivery cannula are removed leaving anchor on atrial side of leaflet. E. Instrument is withdrawn through apex. F. ACT length is adjusted under ultrasound guidance and tied off outside the apex.
Figure 4.
Figure 4.
Leaflet imaging during grasping. A. Grasp positioning delivery channel 2mm from leaflet free edge. B. Delivery channel is positioned 4mm from free edge. C. Delivery channel is positioned over 6mm from free edge. D. While anterior mitral leaflet (AML) is grasped, posterior mitral leaflet (PML) beats against optical finger. E-G. Three images over cardiac cycle corresponding to grasp of AML while PML beats on the optical finger.
Figure 5.
Figure 5.
Image-based validation of anchor placement. A. Imaging previously-placed chordae for verification or for implanting additional chordae. B-C. Verifying if an anchor has been successfully delivered. B. Unsuccessful delivery – anchor can be seen in delivery channel. C. Delivery success – Artificial Chordae Tendineae (ACT) can be seen passing through leaflet.
Figure 6.
Figure 6.
Ultrasound imaging after Artificial Chordae Tendineae (ACT) delivery. A. Anchor and chordae in P2 can be seen together with mitral leaflets. (Also see Video 2.) B. Regurgitant flow generated by shortening the ACT from outside the apex as visualized on color Doppler.
Figure 7.
Figure 7.
Post-surgical views of Artificial Chordae Tendineae (ACT) placed in the posterior mitral leaflet. A. Single chordae. B. Two chordae.
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