Minimally Invasive Complex Mitral Valve Repair After Healed Endocarditis

The authors present the case of complex mitral valve pathology resulting from healed endocarditis. The patient was a 52-year-old otherwise healthy man who presented with severe dyspnea on exertion and fatigue. He carried a diagnosis of remote bacterial endocarditis from a dental infection, which was treated with IV antibiotics. At presentation, his echocardiogram showed a complex pathology with anterior and posterior leaflet flails of the A2 and P2 as well as a patent foramen ovale. His ventricular function was preserved and there were no signs of vegetations or abscess. His blood cultures were negative. The patient was offered a minimally invasive approach to his operation with the goal of repairing his mitral valve and a replacement with a mechanical valve as a backup.

The operation was carried out with a single lumen tube intubation and via a 1.5 inch right minithoracotomy in the lateral chest fourth intercostal space. The pectoralis major was reflected and the entry interspace was infiltrated with a combination of liposomal bupivacaine and regular bupivacaine. The soft tissue retractor was inserted. A right groin cutdown was performed to expose the anterior aspect of the femoral artery and vein, which were cannulated using a 17 Fr and 25 Fr femoral venous cannulas. Once cardiopulmonary bypass was established, the pericardium was opened longitudinally 2 cm above the phrenic nerve and the exposure was achieved with pericardial stay sutures. A root vent was applied to the aorta and the heart was arrested using a deployable crossclamp and 1200 ml of Del Nido cardioplegia was administered. Redosing was performed with 500 ml at 80 minutes. The heart was opened at the interatrial groove and the atrium was exposed. Examination of the valve showed a perforated anterior leaflet at A2 1 cm from the edge. All chordae to A2 were ruptured and the most of the chordae to P2 were ruptured too. The annulus was dilated.

After applying the annuloplasty ring sutures, the anterior leaflet perforation was probed and it was determined that the tissues were appropriate for primary closure using CV6 Gortex sutures interrupted. After this, the anterolateral papillary muscle was used to anchor a set of adjustable gortex loop system (ONX-Cryolife, Kennesaw, GA). The three loops were used on the A2 segment using a locking figure of eight technique to allow incremental adjustment. Once the desired anterior leaflet height was achieved, the posterior leaflet was reanchored using a second set of adjustable gortex loop system anchored to the posteromedial papillary muscle. All three loops were used on the P2 segment with the same locking figure of eight technique and the height of the P2 segment was adjusted. A cleft between P1 and P2 was closed using CV6 gortex.

The valve was tested using a powered suction irrigator and Del Nido Cardioplegia solution. A true sized 40 mm Physio 2 ring (Edwards, Irvine, CA) was used to stabilize the annulus. Static testing showed trivial regurgitation, so the left atrium was closed in the standard fashion and the patient was weaned off cardiopulmonary bypass. The crossclamp time was 125 minutes with a total cardiopulmonary bypass time of 140 minutes.

The patient had a prompt recovery and was discharged home in good condition. Follow-up echocardiogram showed trace mitral regurgitation and a mean mitral gradient of 2 mm Hg.

Discussion:

Bacterial endocarditis is a common event in cardiac surgery practice. Some cases of acute bacterial endocarditis can and likely should be repaired if debulking the infection is permitting of it. Healed bacterial endocarditis allows the surgeon to work with sterile tissue and therefor limits the surgical debulking, as long as the tissue quality is appropriate. A minimally invasive approach for acute bacterial endocarditis should only be undertaken when the pathology is isolated to the mitral and tricuspid valves, as an aortic root abscess would be difficult to manage via a right minithoracotomy.

The Leipzig Loop technique pioneered by Professor Mohr truly catalyzed the movement from resect to respect of the mitral valve. This is the authors’ preferred approach in the treatment of fibroelastic disease and Barlow’s disease whenever possible. Certain principles of chordal reconstruction are tried and true and have been published by Borger and the Leipzig group (1). One of the benefits of using a chordal reconstruction is the application of true-sized annuloplasty rings, which have been proven to be bigger than in resection techniques as demonstrated by Falk, et al (2).

Adjusting and maintaining the leaflet height when tying using gortex chords is imperative. Different techniques have been used over the years, including using a surgical clip, bulldog clamp, specialized annuloplasty rings, and other devices to maintain the height when tying. More recently, the use of the locking figure of eight (3) and autologous pericardial pledget (4) techniques have been proposed. The authors favor the former given the reproducibility and ease of use. Both these techniques differ from the Leipzig technique, which advocates for pre-measured loops. The authors feel that having the ability to change the height of the leaflet prior to committing is of great benefit, especially in complex repairs.

The use of adjustable chords is a versatile technique to correct leaflet prolapse and flails of all segments of the mitral valve. The technique is reproducible and effective.

References

1. Kuntze T, Borger MA, Falk V, Seeburger J, Girdauskas E, Doll N, et al. Early and mid-term results of mitral valve repair using premeasured Gore-Tex loops (‘loop technique’). Eur J Cardiothorac Surg. April 2008;33(4):566–572.
2. Falk V, Seeburger J, Czesla M, Borger MA, Willige J, Kuntze T, et al. How does the use of polytetrafluoroethylene neochordae for posterior mitral valve prolapse (loop technique) compare with leaflet resection? A prospective randomized trial. J Thorac Cardiovasc Surg. 2008 Nov;136(5):1200-1206.
3. El Gabry M, Jakob H, Lubarski J, Mourad F, Shehada S-E. Minimally invasive video-assisted mitral valve repair using PTFE-chordae: a simplified technique. CTSNet. August 2018. doi:10.25373/ctsnet.6990317.
4. Amirghofran AA. Adjustable pericardial lock technique for complex mitral valve repair. CTSNet. October 2019. doi:10.25373/ctsnet.9955976.

Disclosure

Dr Castillo-Sang is a proctor for Edwards Lifesciences and Cryolife in the mitral valve field.

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