With the heart empty, a ventricular pacing wire was placed. After discontinuing cardiopulmonary bypass and administering protamine, decannulation was performed. The purse-string sutures were tied, and the femoral artery was reinforced using 5-0 Prolene suture. A single chest tube was left in the pleural space. For pain relief, an On-Q pain relief system was inserted (I-Flow Corporation, Lake Forest, CA USA). Two catheters were placed to continuously deliver 0.25% of bupivicaine for 72 hours. The thoracotomy incision was closed in the routine fashion.
Postoperatively, no mitral regurgitation was noted immediately (postoperative video available online at http://links.lww.com/INNOV/A28) or on the echocardiogram done 2 weeks later. There was a decrease in the mitral valve tenting height from 0.8 cm to 0.3 cm (Fig. 3). She had significant improvement of her symptoms, being in New York Heart Association heart failure class II at the time of discharge and at 7 months follow-up. The echocardiogram performed 4 months after the surgery demonstrated no mitral regurgitation and a decrease in the end-systolic and end-diastolic diameters from 6.2 cm and 5.5 cm to 5.7 cm and 5.2 cm, respectively. The ejection fraction improved slightly to 25%, and the mitral valve tenting height remained at 0.3 cm.
Functional, or secondary, mitral insufficiency in patients with reduced left ventricular systolic function is usually a result of annular dilatation and papillary muscle displacement, with the mitral leaflets being anatomically normal.1 Whether to perform mitral valve surgery in patients with severe mitral regurgitation and advanced heart failure is controversial, with the published data showing mixed results.2–4 Presently, the most common type of surgery performed in these cases is an undersized mitral annuloplasty, which was popularized by Bolling and colleagues.5 In this technique, a small (size, 24–26 mm) mitral annuloplasty ring is used, which causes a reduction in the anteroposterior (septolateral) diameter of the mitral valve, increasing the surface of coaptation. The drawback with the undersized annuloplasty technique is a high rate of failure. In a study of 585 patients who had undersized annuloplasty surgery during a 17-year period, the authors noted that at least moderate mitral regurgitation developed 6 months postoperatively in 28% of the patients.6
To reduce the mitral valve repair failure rates in these patients, a number of innovative approaches have been developed, which include the use of geometrically shaped annuloplasty rings, anterior leaflet augmentation, second-order chordal cutting surgical relocation of the posteromedial papillary muscle, and the use of external restraint devices.7–9 Some have focused their attention on fixing the subvalvular apparatus in an attempt to reduce the recurrence of mitral regurgitation. Hvass and colleagues10,11 were the first to report the use of a 4-mm Gore-Tex tube encircling the trabecular base of both papillary muscles in patients with ischemic functional mitral regurgitation. They presented the results of 37 patients with ischemic mitral regurgitation who underwent this procedure. A moderately undersized mitral annuloplasty ring was placed in most patients, with the last 10 patients of the study receiving a normal-sized prosthetic mitral ring. All patients also underwent coronary artery bypass graft surgery. The mean age of the patients was 56 years; all were in New York Heart Association heart failure class III to IV; had a mean (SD) ejection fraction of 29.5% (5.5%), left ventricular end-diastolic diameter of 70 (0) mm, and left ventricular end-systolic diameter of 55 (5.6) mm; and had pulmonary hypertension of higher than 60 mm Hg. Early residual regurgitation was none to trivial in 31, was mild in 2, and was moderately severe in 2. At 1-year follow-up, the ejection fraction improved to a mean (SD) of 49% (6%), the mean (SD) end-diastolic and end-systolic diameter were 56 (5.5) and 50 (5.5), and the mean (SD) pulmonary artery systolic pressure was reduced to 45 (11) mm Hg.
All of the above-mentioned procedures were performed via a standard median sternotomy. Minimally invasive valve surgery, when compared with median sternotomy, has been shown to decrease complications and reduce hospital length of stay, use of resources, and mortality, especially in high-risk patients such as the elderly and persons with obesity.12–17 Thus, the possibility of combining both techniques is promising because it has the potential of reducing the surgical trauma with minimally invasive surgery and may improve the short- and long-term results of the mitral valve repairs in these high-risk individuals. Another underestimated benefit is the improved visualization of the infravalular apparatus via a minithoracotomy approach. The patients who we select for this procedure are those with severe, functional mitral regurgitation who have ejection fractions of less than 40%.
We demonstrated the feasibility and the safety of a minimally invasive approach for papillary muscle sling placement during mitral valve repair for functional mitral regurgitation. The durability of this technique and its long-term effects need to be further evaluated.
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