On-Pump Beating Heart Mitral Valve Repair Through Right Anterior Mini Thoracotomy

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The authors present a case of an on-pump beating heart mitral valve repair performed minimally invasively through a small right anterior thoracotomy. 
 
The patient was a 74-year-old male with a prior history of coronary artery bypass grafting (CABG) who presented with chronically worsening dyspnea on exertion. 
 
Transesophageal echocardiography (TEE) demonstrated severe, anteriorly directed eccentric mitral regurgitation (MR) with P2 scallop flail. The mechanism of MR was secondary to torn chordae to P2, as will be shown. The ejection fraction was preserved at 65 percent, with no wall motion abnormalities, and the left ventricle was non-dilated. There were no other regurgitant lesions. All prior CABG conduits were patent. 
 
Given the added risk of reoperative sternotomy in a patient with prior CABG grafts, a minimally invasive approach through a right anterior thoracotomy was deemed safe and feasible for this patient. With this approach, given the inability to dissect and clamp the left internal mammary artery (LIMA) to left anterior descending artery (LAD), the options were to perform the repair on-pump beating heart vs with administration of systemic cardioplegia and performing under fibrillation. 
 
The set up and exposure were as follows: The patient was cannulated peripherally for bypass through the right femoral vessels. An anterolateral mini thoracotomy was made in the right fifth intercostal space. Dense adhesions from prior surgery involving right internal mammary (RIMA) harvest were dissected. The pericardium was opened to expose Sondergaard’s groove and the ascending aorta, with care taken not to dissect into the patient’s right-sided coronary conduit. An aortic root vent was inserted. CPB was initiated, and the patient was cooled to 30 degrees Centigrade. Once the patient was no longer ejecting, the left atrium was opened to expose the mitral valve through Sondergaard’s groove. 
 
Starting at the anterolateral commissure and working counterclockwise along the posterior annulus, 2-0 Ethibond annuloplasty sutures were placed, followed by the anterior annulus. The cusps of the mitral valve were examined as shown. Starting with P1, the posterior leaflet was unfurled to examine for pathology. At the leading edge of P2, there was a ruptured chord. The surgeons proceeded to examine P3 and the anterior leaflet, working from A3 to A1. No further pathology was identified. 
 
The in-situ pathology is as shown. One of the benefits of this operation was the ability to examine the mitral pathology on the beating heart. Understanding that the pathology was secondary to ruptured chords to P2, the decision was made to proceed with neochord creation. The valve was sized to be a 30 mm Physio mitral ring based on the intertrigonal distance and the length of the anterior leaflet. The relationship to the papillary muscle was examined. 
 
The distance from the tip of the papillary muscle to the leaflet edge was measured to be 16 mm, which guided the selection of the pre-made Onyx polytetrafluoroethylene (PTFE) cords. 
 
The neochord apparatus was secured to the tip of the papillary muscle and set aside to be placed at the leaflet edge once the annuloplasty was complete. The annuloplasty sutures were placed through the sewing ring in standard fashion, and the annuloplasty ring was lowered into the field. The neochords were preserved as the surgeons prepared to set the annuloplasty ring. The annuloplasty sutures were tied in standard fashion, starting with the anterolateral commissure and across the anterior leaflet. The sutures were then alternated laterally to medially across the posterior leaflet. The valve pathology was examined once again after the annuloplasty was complete. Two neochords were placed through the leaflet edge of the P2 cusp. At the conclusion of the case, the leaflet coaptation was adequate by direct observation on the beating heart. There was no residual MR, and the ring was well seated, as demonstrated by the postoperative TEE. 
 
The patient’s postoperative course was uncomplicated, and the patient was discharged home on postoperative day five. The authors believe this method to be technically feasible, safe, and effective as an alternative in patients in whom the conventional approach would involve reoperative sternotomy and extensive dissection to isolate prior patent CABG grafts to achieve arrest. 

References

1. Matthew A. Romano, Jonathan W. Haft, Francis D. Pagani, Steven F. Bolling, Beating heart surgery via right thoracotomy for reoperative mitral valve surgery: A safe and effective operative alternative, The Journal of Thoracic and Cardiovascular Surgery, Volume 144, Issue 2, 2012, Pages 334-339.

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