Totally Endoscopic Mitral Valve Repair: TEE Guided Using the Loop Technique

A totally endoscopic mitral valve repair using the loop technique was guided in real time by transesophageal echocardiography (TEE). The case illustrates the procedural advantages of combining minimal access with precise imaging and premeasured chordae implantation to correct posterior leaflet prolapse (Supplemental Video). ¹

The procedure was performed on a 44-year-old male patient diagnosed with severe mitral regurgitation. The pathology primarily involves a prolapse of the P2 segment of the posterior mitral leaflet, confirmed by TEE imaging. The procedure showcases several refined techniques for totally endoscopic repair, emphasizing precision, planning, and minimally invasive execution. ²

TEE plays a central role throughout the operation, offering detailed anatomical and functional visualization of the mitral valve before, during, and after the repair. ² A perioperative TEE was used to determine the necessary chordae length, a systolic view (at 0°) that provided the best simultaneous imaging of the prolapsed segment, opposing nonprolapsing segment, and head of the papillary muscle was defined. Measurements were obtained for the distance between the top of the fibrous head of the papillary muscle and the lowest point of the coaptation of the 2 leaflets was measured, ¹ 22 mm in this case; the number of chordae; and the precise location of implantation due to a notably long P2 segment.

Cardiopulmonary bypass was established using femoral cannulation, and surgical access was achieved via a periareolar approach. ² This technique involves incision to the upper lateral quadrant of the nipple. Once the incision has been made, it is essential that the surgeon cuts straight down through the fat tissue and that the pectoralis major muscle and is perpendicular to the chest wall. The surgeon must digitally palpate the intercostal spaces (ICSs). The camera port is a 10 mm incision made in the same ICS as the working incision that facilitates the 3-dimensional 4K 30° Storz endoscopic camera system. ² In this particular case, both the working incision and camera port are placed in the fourth ICS, which is most commonly used in mitral and tricuspid surgery. Please note that we perform aortic valve surgery through the third ICS.

The surgical approach began with careful dissection of the plane between the ascending aorta and the right pulmonary artery. ³ The Chitwood clamp was positioned high through the dissected plane, between the ascending aorta and the right pulmonary artery, to preserve the surgical field and facilitate an extensive aortotomy for optimum exposure. ³

Further dissection of the superior vena cava free from the surrounding pericardium and of the roof of the left atrium was used to achieve enhanced exposure for a broad left atriotomy. Upon entry into the left atrium, the endoscopic camera was used to reevaluate the leaflet anatomy, revealing deep indentations between P1/P2 and P2/P3, as previously noted by the TEE, the prolapsing parts of the leaflets and the anchoring points of the neochords on the leaflet were marked with methylene blue. ⁴

Two sets of 4 premeasured 22 mm 3-0 polytetrafluoroethylene (PTFE; Sheramon) loops were selected—anchored to the posteromedial and to the anterolateral papillary muscles, respectively. ⁴ Four neochords were then selected (2 from the posteromedial set of loops and 2 from the anterolateral) and organized and implanted in reverse order from lateral to medial across the P2 segment, ensuring precise spacing (around 10 mm between) and symmetric distribution. All neochords are prefabricated lengths, made of PTFE by Serag Weissner.

A key aspect involved the implantation site on the leaflet body—not the free edge—to avoid an excessively long posterior leaflet. This tactic balanced leaflet height among P1, P2, and P3, promoting a central and posteriorly shifted coaptation line, reducing the risk of systolic anterior motion (SAM). Once all chords were implanted, the clefts between P1/P2 and P2/P3 were further addressed with direct suturing.

A flexible, malleable 36 mm annuloplasty ring was chosen based on intratriagonal distance measured intraoperatively with TEE and visually confirmed by using a silicone Medtronic sizer (Dublin, Ireland). The ring was inserted without its holder, a maneuver that facilitated passage through the restrictive periareolar working incision. Ten sutures were used for ring fixation. The order was maintained using an LSI suture organizer to avoid entanglement, and a COR-KNOT automated fastening device (LSI SOLUTIONS, Victor, NY, USA) was used to secure the annulus. The atriotomy was closed in 2 layers: horizontal mattress followed by a running over-and-over suture. Using a large size ring is of paramount importance for avoiding SAM, especially if the loop technique (as opposed to resection) is used.

Please note that we use no water testing at any stage of our loop repair procedure (the only exceptions being redo cases, endocarditis/leaflet resection cases, and finally transcatheter edge-to-edge repair removal cases). Our strategy is solely based on TEE done before the institution of cardiopulmonary bypass.

A final TEE assessment demonstrated excellent valve competence with a mean gradient of 2.36 mm Hg and a maximum gradient of 4.67 mm Hg. ⁵ A broad coaptation length of 17 mm was measured, ensuring long-term durability and minimized risk of recurrent regurgitation.

This case exemplifies the technical precision and reproducibility of the loop technique in endoscopic mitral valve repair, emphasizing the role of TEE in guiding real-time decision-making and confirming anatomical restoration.