Repair of Acute Severe Mitral Regurgitation Due to Iatrogenic Papillary Muscle Rupture

The authors present a case of mitral valve repair for acute iatrogenic papillary muscle rupture leading to a flail anterior leaflet. What makes this case unique is the type of pathology, the challenge in exposure of the valve as well as the subvalvular apparatus given the small left atrial size, and the ability to preserve the valve. 
 
Briefly, this patient was a 65-year-old with symptomatic premature ventricular contractions (PVC) who presented following transcatheter ablation. The procedure was complicated by new severe mitral regurgitation due to flail anterior leaflet, necessitating urgent mitral valve surgery in the operating room. A left heart catheterization demonstrated nonobstructive coronary artery disease (CAD). 
 
A transesophageal echocardiogram revealed a small left atrium with preserved ejection fraction, flail anterior mitral valve leaflet due to a torn chord or papillary muscle, and severe mitral regurgitation with an eccentric posteriorly directed jet. Surgery was performed via median sternotomy, and the valve was exposed through Sondergaard’s interatrial groove. 
 
Visualization was challenging due to the small left atrial size; however, adequate exposure was obtained, and the pathology became clear once the valve was evaluated. There was a flail A2 segment due to the rupture of the medial papillary muscle with the attached chords. Additionally, a hematoma was present on the anterior leaflet in the area of the flail segment. A saline test confirmed the incompetence of the valve in that location. 

The repair began with the placement of annuloplasty sutures circumferentially while evaluating the rest of the valve segments, which appeared intact with no degenerative changes and no mitral annular calcification. The subvalvular apparatus was then exposed, and the medial papillary muscle was identified along with the location of the detachment injury. Two Gore-Tex chords were passed into an intact, healthy area of the papillary muscle. The exact location of the flail segment was then marked, and the torn supportive apparatus was resected. The two neochords were then passed at the marked sites and tied at the appropriate height. At this point, the valve was tested with a saline test, which showed no residual regurgitation. 

The intercommissural distance corresponded to a 32 mm band size; however, since the posterior leaflet showed significant height, the decision was made to oversize the annuloplasty at 34 mm and use a flexible incomplete band. After tying down the band, the saline test showed significant residual regurgitation, necessitating adjustments to the neochord heights to ensure adequate leaflet coaptation. The repeat test showed a competent valve, and the neochords were locked. 

A postoperative transesophageal echocardiogram (TEE) demonstrated trace central mitral regurgitation (MR), no systolic anterior motion, and normal gradients across the valve. The patient recovered well and was discharged five days later. At the six-month follow-up, a repeat transthoracic echocardiogram (TTE) showed a stable repair with no regurgitation, no systolic anterior motion, and preserved ejection fraction.  

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