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Redo Endoscopic Assisted A2 Mitral Repair with Fibrillatory Arrest

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posted on 25.07.2022, 20:43 authored by Mario Castillo-Sang

Minimally invasive mitral valve surgery in patients with prior sternotomies is safe and effective in resolving the mitral pathology; this is true for both repairs  and replacements (1). Cases of prior valvular surgery tend to be more straightforward when addressing myocardial protection and are typically amenable to cardioplegic arrest. Furthermore, cases of prior coronary bypass grafts can change the dynamics for minimally invasive approaches if the left internal mammary is patent. This is especially a factor in patients with a depressed left ventricular ejection fraction (LVEF). In the later cases, use of fibrillatory arrest achieves the objective of myocardial protection while allowing access to the mitral valve with a near bloodless field (2–4).

This case illustrates the combination of different techniques used to achieve a reoperative mitral valve repair operation. The patient was a fifty-nine-year-old man with known anterior leaflet flail who presented with profound dyspnea on exertion and fatigue. He had undergone a coronary bypass grafting operation ten years prior. The patient’s left ventricular ejection fraction was normal, and it had no aortic or tricuspid insufficiency. His recent coronary angiogram showed widely patent LIMA-LAD and vein-obtuse marginal artery grafts.

Procedure

The proposed operation was an endoscopic-assisted mitral valve repair with fibrillatory arrest. Use of neochordal reconstruction for repairs was favored. Furthermore, an adjustable technique was preferred in the case of the anterior leaflet, using the adjustable ChordX mitral repair system. The repair started with annuloplasty sutures to conform the annulus and valve for a familiar surgeon’s view. During this time, the valve was analyzed and static tested using Del Nido cardioplegia through a laparoscopic suction irrigator. At this point, the neochordal system was anchored to the anterolateral papillary muscle. Each of the three pairs of neochordae were passed on the anterior leaflet using a locking figure eight configuration (which can be adjusted for height), initially leaving the leaflet in an intentionally prolapsed state. This technique allows adjustment to specified areas of the diseased segment. To adjust, one must hold the neochord with one forceps and the leaflet with another forceps. Next, one must push the leaflet down while holding tension on the neochordae. The valve was then static tested, and the process is repeated as needed, without tying the neochordae. 

With the valve pressurized, the annuloplasty ring was sized by making sure the edge of the sizer remained within and flush to the annuloplasty sutures, not covering their point of entry to the annulus. An ink test was performed, and the coaptation zone was evaluated. If the coaptation area is ample, then the measured ring is used. However, if the zone is short (less than 1 cm), then a new ring (one size smaller) is selected. Once the annuloplasty ring was seated, one last static testing was performed. One final adjustment was carried out as needed, and the neochordae were tied.

In this case, the patient underwent a full recovery. He was discharged on postoperative day three. Predischarge echocardiogram imaging showed no residual mitral regurgitation, with a mean gradient of 2 mmHg. The patient’s ventricular function was normal. He was seen at one week and then one month after surgery with good health.

Closing Remarks

Fibrillatory arrest can make reoperative minimally invasive mitral valve surgery in the presence of patent grafts safer (1). The operation can also be performed on a beating heart if there is no more than trace aortic insufficiency (5). In cases of a depressed LVEF, including acute myocardial infarction (MI) with ruptured papillary muscle complicating mitral regurgitation, the decision to not arrest the heart allows for conservation of what little left ventricular function there is. As part of the myocardial protection strategy, it is important to mitigate intracardiac air in both scenarios. A root vent, when possible, is an important factor. In cases of porcelain aorta, leaving a small left ventricular vent open while closing the left atrium is important.

References

1. Seeburger, Joerg, et al. “Minimally invasive mitral valve surgery after previous sternotomy: experience in 181 patients.” The Annals of thoracic surgery 87.3 (2009): 709-714.

2. Umakanthan, Ramanan, et al. “Safety of minimally invasive mitral valve surgery without aortic cross-clamp.” The Annals of thoracic surgery 85.5 (2008): 1544-1550.

3. Ricci, Marco, et al. “Multiple valve surgery with beating heart technique.” The Annals of thoracic surgery 87.2 (2009): 527-531.

4. Ad, Niv, et al. “Minimally invasive mitral valve surgery without aortic cross-clamping and with femoral cannulation is not associated with increased risk of stroke compared with traditional mitral valve surgery: a propensity score-matched analysis.” European Journal of Cardio-Thoracic Surgery 48.6 (2015): 868-872.

5. Suzuki, Yoshikazu, Francis D. Pagani, and Steven F. Bolling. “Left thoracotomy for multiple-time redo mitral valve surgery using on-pump beating heart technique.” The Annals of thoracic surgery 86.2 (2008): 466-471.

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