Novel 360-Degree Tutorial of Minimally Invasive Mitral Valve Surgery

This novel 360-degree video tutorial demonstrates mitral valve repair through a right antero-lateral minithoracotomy approach. Using integrative technology, the viewer can immerse themselves into the procedure by manipulating the directional viewpoint and magnification online via their computer’s mouse or finger scrolling on a tablet or smartphone device.

The Procedure 

To start the procedure, anesthesia is provided per institution protocol. Single or double-lumen intubation is used, depending on case complexity. A transesophageal echocardiography (TOE) aids correct cannula placement, and anatomical and functional mitral valve views. Defibrillator pads are then placed across the chest wall, and patient positioning is supine with right chest elevation and right arm tucked laterally. 

Two Iron Assistant instrument holders are positioned on each side of the patient to hold the endoscopic camera and atriotomy retractor. Then, right femoral vessels are cannulated through a 3–4cm incision inferior to the inguinal ligament. Next, a multistage vacuum-assisted femoral venous cannula (Bio-Medicus-Medtronic, size 21Fr or 25Fr) and a straight flexible arterial cannula (Edwards Optisite, size 18Fr or 20Fr) are introduced via guidewire. TOE confirms correct placement, and the cannulas are connected to the cardiopulmonary bypass machine and bypass is commenced. 

A 4–6cm right submammary incision then enters the third or fourth intercostal space. An endoscopic 0-degree camera is introduced through a 10mm port, one space above the minithoracotomy. CO2 is then connected to this port. After this, the minithoracotomy is accessed by an Alexis wound retractor and a Geister rib retractor, with the latter placed atop a malleable plate to retract the diaphragm. 

Next, a pericardiotomy is performed one-third of the way back from the front of the pericardium. This leaves enough tissue for closing the pericardium later and permits a pericardial shelf that, laterally retracted, secures the right lung. The left atrium (LA) is exposed by placing two suture retractors in the posterior pericardial tissue, and a third suture in the interatrial groove, with the latter exteriorized through a 5mm anterior chest port just lateral to the sternal border. 

The ascending aorta is then cannulated endoscopically with two pledgeted purse string sutures. Using one of these sutures, a root cannula is inserted, connecting to the cardioplegia and vent line respectively. A detachable Glauber clamp is placed into the ascending aorta, and anterograde cardioplegia delivered into the aortic root. 

Then a left atriotomy is performed. A detachable atrial lift retractor (ValveGate Tm-Geister) is placed and secured through the parasternal port. The existing plate is repositioned over the diaphragm into the inferior-posterior LA wall. Adequate venting is achieved by continuous suction through the aortic root and by placing a malleable cannula in one of the pulmonary veins. This results in good and direct visualization of the mitral valve. 

The video accompanying this article presents two cases. The first shows redundant posterior leaflet with P1 and P2 prolapse, and a competent P3 and anterior leaflet. The valve is repaired by trimming the prolapsed P1 chordae and resecting a wedge of P2, and the gap is repaired with continuous Prolene suture. 

The second case shows a prolapsing P2 from chordae rupture. A fabricated neochordae is implanted spanning from the papillary muscle to the edge of the leaflet. The neochordae is created using the ValveGate Mohr ruler, which facilitates the creation of the loops with Gore-Tex suture. 

In both cases, a semirigid complete mitral ring is placed with interrupted sutures. A water pressure test shows good valve competence. The atriotomy is then closed. 

Ventricular pacing wires are positioned and exteriorized through the parasternal port. The cross-clamp is then removed after deairing maneuvers, but the aortic root vent is kept in as long as possible to facilitate complete deairing. Following cardiac reperfusion and echocardiographic assessment, the root cannula is removed and the two purse sutures knotted. The pericardium is then approximated with interrupted sutures. A drain is placed one or two intercostal spaces below the minithoracotomy. 

Femoral decannulation is completed once the patient is stable. The purse strings are then knotted, with occasional placement of an extra haemostatic suture. 

The minithoracotomy and groin access are then closed in layers.

References

1. Speziale G, Santarpino G, Moscarelli M, et al. Minimally invasive mitral valve reconstruction: Is it an "all-comers" procedure? Journal of cardiac surgery. 2021.
2. Modi P, Hassan A, Chitwood WR, Jr. Minimally invasive mitral valve surgery: a systematic review and meta-analysis. Eur J Cardiothorac Surg. 2008;34(5):943-952.
3. Cetinkaya A, Geier A, Bramlage K, et al. Long-term results after mitral valve surgery using minimally invasive versus sternotomy approach: a propensity matched comparison of a large single-center series. BMC cardiovascular disorders. 2021;21(1):314.
4. Dokollari A, Cameli M, Kalra D-KS, et al. Learning curve predictors for minimally invasive mitral valve surgery; how far should the rabbit hole go? Journal of cardiac surgery. 2020;35(11):2934-2942.
5. Holzhey DM, Shi W, Borger MA, et al. Minimally invasive versus sternotomy approach for mitral valve surgery in patients greater than 70 years old: a propensity-matched comparison. Ann Thorac Surg. 2011;91(2):401-405.

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