Totally Endoscopic Mechanical Mitral Valve Repair

In this CTSNet series, Dr. Mario Castillo-Sang presents innovative, totally endoscopic cardiac procedures for a variety of conditions. Stay tuned for more series videos in the coming weeks.    

The authors present the case of a mechanical mitral valve repair in a 57-year-old female patient who had previously undergone mitral valve replacement with an On-X 27/25 mechanical valve at an outside facility two years prior. The patient was admitted through the emergency department to the authors’ institution in cardiogenic shock and eventually experienced ventricular fibrillation arrest. She also had a previous history of bypass surgery. The patient was resuscitated and taken to the catheterization lab, where it was found that her Peyton graphs ventricular contractility was slightly diminished and the mitral valve prosthesis exhibited severe transvalvular regurgitation due to one of the leaflets not completely closing. 

The patient was immediately taken to the operating room for mechanical valve replacement while on inotropic and pressure support. The procedure was performed endoscopically, utilizing a 2.5-centimeter incision in the fourth right intercoastal space as a working port, along with a 10 mm port in the third intercostal space for a 30° angled endoscope. Cannulation was performed via a right axillary cutdown for arterial inflow and a percutaneous femoral venous from the left groin. 

Protection was performed through an integrated cardioplegia and arresting the hardware with a signet cross-clamp. The left atrium was opened through the interatrial groove, and exposure of the valve was obtained using the HV retractor. 

Inspection of the valve immediately showed that the posterior leaflet was locked by a piece of remnant chordae that was protruding through the valve mechanism. There were also other areas toward the anterior leaflet that were insinuating toward the valve but were not going through it. Given the patient's hemodynamic condition and preceding history, the authors aimed to make the operation as short and effective as possible. Utilizing a fine narrow fog, the authors were able to grab the different areas of the protruding remnant chordae and cut them using a combination of endoscopic scissors and a #11 blade scalpel. 

All residual uncut chordae were subsequently resected. There were no signs of thrombosis in the mechanical valve. The valve had been implanted in an anatomical position with the leaflets horizontal; however, this positioning was incorrect for this valve because the structure of the housing can block the left ventricular outflow tract (LVOT). For this reason, the authors used the stock valve turning device to position the valve facing 11 o’clock. The valve was static-tested, and the left atrium was closed in one layer. 

A completion echocardiogram showed a good functioning mitral valve with no transvalvular regurgitation and a mean gradient of 3 mmHg. The patient tolerated the procedure well and was extubated within six hours. Discharge to home occurred on postoperative day seven. 
 
Discussion 

A ‘locked’ mechanical valve leaflet more often has a thrombotic or panus formation origin (1). In some cases, the lock can be due to the protrusion of subvalvular apparatus through the valve, as was the case here (2). These patients can present with pulmonary edema and hemodynamic compromise, necessitating prompt diagnosis and therapeutic intervention. The implantation of a mechanical mitral valve is nuanced by the actions needed to prevent mechanism obstruction by the chordae or residual chordae. Predicting which chordae will place the mechanism at risk and resecting them is essential, especially in the setting of rheumatic valvular disease. Defining the LVOT is crucial to ensure that the valve is positioned in the appropriate anti-anatomical position to prevent any form of LVOT obstruction (3). 

References

1. Asil S, Çelik M, Kadan M, Yüksel UÇ, Bolcal C, Barçın C. Stuck leaflets in prosthetic heart valves with different etiology and treatments.
2. Agostini F, Click RL, Mulvagh SL, Abel MD, Dearani JA. Entrapment of subvalvular mitral tissue causing intermittent failure of a St Jude mitral prosthesis. Journal of the American Society of Echocardiography. 2000 Dec 1;13(12):1121-3.
3. Westerdale JC, Adrian R, Squires K, Chaliki H, Belohlavek M. Effects of bileaflet mechanical mitral valve rotational orientation on left ventricular flow conditions. The Open Cardiovascular Medicine Journal. 2015 Jun 26;9:62.

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