A Mitral-MICS for Every Mitral Pathology: What We've Learned After 120 Cases

Case Presentations
This guide shows two groups. The first group is mitral valve repair, including:

1. Posterior prolapse
2. Barlow disease
3. Commissure fusion
4. Mitral annular dilatation

There are associated procedures, such as how to make the loop, automated suturing device, 3D technology, and atrial fibrillation ablation.

The second group is mitral valve replacement, including:

1. Endocarditis
2. Rheumatic disease
3. Redo-MVR

There are associated procedures as well, such as left atrial appendage closure and tricuspid valve repair (Figure 1 in the video).

Surgical Techniques and Videos

General Surgical Technique
A right minithoracotomy was performed in the 4th-5th intercostal space (ICS). Two accessory ports (5 mm) were used to insert the Chitwood aortic clamp (right 3rd ICS, mid-axillary line) and video camera (right 4th ICS). A Mohr atrial retractor (Geister™), long-shafted instruments for minimally invasive surgery (Geister™), and long-shafted knotters were used, along with a Storz™ video camera with a mechanical arm. Long arterial and venous cannulas (Edwards™ or Medtronic™) for CPB management were inserted through a minimal incision (3-4 mm) in the femoral artery and vein, and in all cases, their position was guided and controlled by transesophageal echocardiography (TEE).

A single dose of 2,000 ml Bretschneider™ cardioplegic solution was used. De-airing was achieved with a third suction instrument once the left atriotomy was closed together with an aortic venting needle (VN). Cardiopulmonary bypass was continued, reducing perfusion until the CPB pump was stopped with the VN in place. Once the absence of air bubbles in the heart was confirmed by TEE, CPB was briefly reinitiated to withdraw the VN and perform an extra hemostatic suture.

Mitral Valve Repair
Posterior prolapse (loop technique and how to make the loop)
Through a left atriotomy, the valve was explored with a nerve hook. A p2 prolapse was observed, and then the authors performed the neochord (CV-4 or CV-5, Gore-Tex®) according to the loop technique. When the surgeon is placing the mitral annulus stitches, the first assistant starts to create the loops.

After the loop was placed in the posterior papillary muscle, the authors then performed the loop-p2 attachment with Cardionyl or polypropylene suture. A complete mitral ring is used always, and lastly, the valve was tested.

Barlow Disease (loop technique and automated suturing device)
An A2-P1-P2 prolapse was observed on the transesophageal echocardiography (TEE) and was confirmed in the operation. The loop technique was used and an automated suturing device was truly helpful in order to save cross-clamp and cardiopulmonary bypass time.

Commissure Fusion (3D Technology and left atrial fibrillation ablation)
A posterior and anterior commissure fusion was observed after the left atriotomy. Two small incisions are done in both commissures and the commissuroplasties with a complete mitral ring. A left atrial fibrillation ablation was also performed. The 3D technology is useful in order to obtain a better understanding of the pathology, the distances, and even to be able to do a small thoracotomy.

Mitral Annular Dilatation
The patient presented a severe mitral annulus posterior dilatation with normal leaflets. With the annuloplasty technique, the problem was resolved.

Mitral Valve Replacement
Endocarditis
A 1.5 vegetation was observed in both anterior and posterior leaflets. The valve was replaced with a mechanical prosthesis 31 (SJM Regent™, Saint Paul, Minnesota, US).

Rheumatic Disease (left atrial appendage closure)
Severe mitral valve stenosis was diagnosed on the TEE. The valve was then replaced with a bioprosthetic valve 27 (Hancock™II, Medtronic, Minneapolis, US).  In this case, the patient presented a clot inside the left appendage. After this was removed, the appendage was closed with a polypropylene suture running.

Redo-MV Replacement (Tricuspid Valve Repair)
A 50-year-old female patient, treated with MVR five years ago (full sternotomy), was brought to the emergency room for fever associated with moderate posterior mitral valve leak and moderate to severe tricuspid valve regurgitation. In this case, the authors placed two venous cannulas in order to exclude the right atrium. One cannula was placed in the right jugular vein, and the other in the right femoral vein. The infected prosthesis was removed and an MVR was performed with a new mechanical prosthesis 29 (SJM Regent™, Saint Paul, Minnesota, US). Then, a right atriotomy was performed and a Kay technique plus a tricuspid annuloplasty (Tri-Ad™, Medtronic, Minneapolis, US) solved the tricuspid regurgitation.

Discussion
The minimally invasive approach may be routinely performed, with good results in almost every mitral valve pathology. Throughout the last years, the mitral-MICS technique has shown evidence of low short- and long-term mortality and stroke rates (1, 2). It has been associated with lower postoperative bleeding, transfusions, mechanical respiratory assistance time, length of hospital stay, lower postoperative pain, and earlier return to work (3).

In conclusion, if almost every mitral valve pathology can be solved through a minimally invasive approach, why not do it?

References

1. Mihos CG, Santana O, Pineda AM, Lamas GA, Lamelas J. Right anterior minithoracotomy versus median sternotomy surgery for native mitral valve infective endocarditis. J Heart Valve Dis. 2014;23:343–349.
2. Botta L, Cannata A, Bruschi G, Fratto P, Taglieri C, Russo CF, et al. Minimally invasive approach for redo mitral valve surgery. J Thorac Dis. 2013;5 Suppl 6:S686-5693
3. Barbero C, Marchetto G, Ricci D, El Qarra S, Attisani M, Filippini C, et al. Right minithoracotomy for mitral valve surgery: impact of tailored strategies on early outcome. Ann Thorac Surg. 2016;102(6):1989-1994.

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