Mitral valve repair of papillary muscle rupture using multi-neochord reconstruction

The patient was a 68-year-old man with a history of tobacco and alcohol use who presented to an outside hospital for several weeks of intermittent palpitations, worsening over 4 days. He was found to have monomorphic ventricular tachycardia with hemodynamic instability, for which he underwent synchronized cardioversion. Transthoracic echocardiogram demonstrated at least moderate mitral regurgitation (MR) with an echogenic mobile mass on the posterior leaflet. Coronary angiogram demonstrated 90% stenosis of the left circumflex artery, 80% stenosis of the right coronary artery, and 60% stenosis of the distal left anterior descending artery. He was transferred for operative management and consented for planned mitral valve repair versus replacement and coronary artery bypass grafting. The patient consented for publication of this case report, and per Stanford University Policy, institutional review board approval was not required.

Preoperative transesophageal echocardiogram demonstrated severe MR, mobile mass versus prolapse of the P2 and P3 segments, and a left ventricular ejection fraction of 30% to 40% (Figure 1, A, Video 1). The patient underwent median sternotomy and subsequent harvest of the left internal mammary artery and saphenous vein graft. Cardiopulmonary bypass was initiated via aortic and bicaval cannulation. The aorta was crossclamped and the heart was arrested with del Nido cardioplegia. Coronary artery bypass grafting was performed with anastomoses of the left internal mammary artery to the left anterior descending artery and saphenous vein graft to the obtuse marginal and posterior descending arteries. The mitral valve was exposed via left atriotomy, revealing complete rupture of the posterior head of the posteromedial PM (Figure 2, A). The anterior head of the posteromedial PM remained intact. The ruptured PM and its corresponding chordae were resected, and Gore-Tex neochords were placed in 5 locations to provide multiple points of reinforcement. Two neochords were placed in the unruptured anterior head of the posteromedial PM, with one directed to the A3 segment and the other directed to the posteromedial commissural leaflet. Another neochord was passed from the remnant of the ruptured posterior head of the posteromedial PM to the P3 segment. A fourth neochord was anchored partial thickness in the healthy-appearing left ventricular endocardium adjacent to the site of the PMR at a depth of 2 to 3 mm, a variation of the posterior ventricular neochordal repair technique previously described by our group,³ and directed to the P3 segment. Finally, the fifth neochord was placed in the posterior head of the anterolateral PM and passed through the P2 segment (Figure 2, B). On the basis of the size of the anterior mitral leaflet, a 28-mm annuloplasty ring (Sorin Biomedica Cardio S.r.L.) was implanted with appropriate undersizing to enhance leaflet coaptation (Figure 2, C). The ventricle was then pressurized, and the neochords were tied to appropriate length to generate excellent geometry (Figure 2, D, Video 2). The left atriotomy was closed and the aortic crossclamp was removed. An intra-aortic balloon pump was placed via the left common femoral artery. The heart was deaired and weaned from cardiopulmonary bypass. Postoperative transesophageal echocardiogram demonstrated only trace residual MR (Figure 1, B, Video 3). The patient was taken to the intensive care unit postoperatively, where he was extubated on postoperative day (POD) 1. His intra-aortic balloon pump was removed on POD 2, and he was transferred to the floor on POD 4. The last transthoracic echocardiogram on POD 5 demonstrated mild residual mitral regurgitation (Video 4), and he was discharged to home on POD 11.

The gold standard treatment for PMR remains surgical intervention, with 80% of cases treated with mitral valve replacement and just 20% treated with MVr.² When MVr is attempted, numerous techniques have been reported, including resection of the affected leaflet segment, chordal transfer, and reimplantation of ruptured papillary muscle remnant into the site of rupture, adjacent healthy papillary muscle, or the left ventricle wall.¹ Repair with neochords have been described in just a few cases, with Sponga and colleagues⁴ repairing a posteromedial PMR using Gore-Tex neochords placed at the free border of the posterior leaflet, passed through the posterior ventricular wall, and tied down on the epicardial side.

In cases of PMR, repair is often not attempted, given the surrounding friable infarcted tissue. Reimplantation techniques have been associated with high risks of recurrence, potentially because of involution of the edges of the remnants, resulting in shorter papillary muscle exposed to superior traction forces, or compromise of the quality of tissue at the site of reimplantation.¹ Alternatively, leaflet resection may be performed but requires that the rupture be limited to a small enough segment of leaflet, with successful repair being more likely when the rupture involves two thirds or less of the chordae tendineae from one PM head.⁵ Complete rupture of a single papillary muscle head, however, has been reported in 46% to 95% of cases,^1,2 and in our case, complete rupture of the papillary muscle head affected the P2, P3, and posteromedial commissural leaflet segments. We elected to pursue a neochord-based technique. Given concerns about the quality of the surrounding tissue, we performed a multi-neochord reconstruction, passing neochords into the left ventricle wall and various heads of the papillary muscles. This technique allowed us to perform an effective repair of complete rupture of a papillary muscle head, providing several points of reinforcements at multiple locations in the ventricle to maximize the probability of a durable repair. As neochord geometry can be altered by left ventricle remodeling over time, preoperative echocardiography-based valvular and ventricular measures may be used for patient selection, though additional studies are needed to better identify the optimal patient population for this repair technique.