Long term results of mitral valve repair: posterior papillary muscle repositioning versus chordal shortening

Mitral commissural prolapse

Mitral commissural prolapse or flail, either isolated or combined with more extensive degenerative valve disease, imposes several challenges both on its diagnosis and management while being a risk factor for valve reoperation after mitral valve repair. Accurate identification of the prolapsing segment is often not feasible with transthoracic 2D echocardiography, with transesophageal 3D imaging then required for correct diagnosis and surgical planning. Various surgical techniques employed alone or in combination have yielded good results in the repair of commissural prolapse. Herein, we analyze the specific characteristics of commissural disease focusing our attention on 2D and 3D echocardiographic findings and we briefly comment on techniques employed for surgical correction of the disease.

Mitral valve repair over five decades

It has become evident that mitral valve (MV) repair is the preferable treatment for the majority of patients presenting with severe mitral regurgitation (MR). This success clearly testifies that the surgical procedure is accessible, reproducible and is carrying excellent long-lasting results. From the pre-extracorporeal circulation's era to the last percutaneous approaches, a large variety of techniques have been proposed to address the different features of MV diseases. This article aimed at reviewing chronologically the development of these dedicated techniques through their origins and the debates that they generated in the literature.

Repair of the anterior mitral leaflet prolapse

Repair of anterior mitral leaflet prolapse is one of the most challenging aspects in mitral valve repair surgery. In this review, we discuss the various techniques developed over the past three to four decades for the repair of anterior mitral leaflet prolapse, debate the pros and cons of each and compare their results, keeping reoperation for recurrent mitral regurgitation as the focal point of follow-up. At our center, chordal replacement with artificial expanded polytetrafluoroethylene sutures in the form of premeasured loops is the most commonly used technique for repair of anterior mitral leaflet prolapse for the past decade. We recommend and provide justification for the use of this technique, especially when mitral valve repair is performed through a minimally invasive approach. We believe that the trend towards a minimally invasive approach for mitral valve repair will exponentially increase in the next 5-10 years, at least until percutaneous techniques, if at all, become more reliable and safe.

Biomechanical assessment of surgical repair of the mitral valve

Repair of the mitral valve is defined (loosely) as a procedure that alters the valve structure, without replacement, enabling the natural valve itself to continue to perform under the physical conditions to which it is exposed. As the mitral valve is driven by flow and pressure, it should be feasible to analyse and assess its function, failure and repair as a mechanical system. This article reviews the current state of mechanical evaluation of surgical repairs of the failed mitral valve of the heart. This review describes the anatomy and physiology of the mitral valve, followed by the failure of the mitral valve from a mechanical point of view. The surgical methods used to repair failed valves are introduced, while the use of engineering analysis to aid understanding of mitral valve repair is also reviewed. Finally, a section on recommendations for development and future uses of engineering techniques to surgical repair are presented.

Is an anterior mitral leaflet prolapse still a challenge?

Quadrangular resection is the gold standard in the treatment of posterior leaflet prolapse. Anterior leaflet prolapse has been considered a more challenging problem; several techniques are available to treat it, all with the same goal - mitral valve competency. Nowadays, good long-term results are reported, similar to those for posterior leaflet prolapse. Certain improvements may explain these results, especially improvements in transesophageal echocardiography (including three-dimensional echocardiography), which allow the detection of atypical mitral regurgitation and its mechanism.

Complex Bileaflet Mitral Valve Repair (Barlow's) Using the da Vinci Robotic Surgical System

Robotic mitral valve repair (RMVR) is less invasive and potentially more precise. However, RMVR lengthens both cardiopulmonary bypass and arrested heart times. In our initial experience, only posterior leaflet repair and/or annuloplasty were performed. With increasing experience, we have performed more complex bileaflet RMVR. A 50-year-old man presented with severe mitral regurgitation. Transesophageal echocardiography (TEE) demonstrated a complex bileaflet prolapse and preserved left ventricular function. Through a 4 cm working port and with the da Vinci Robotic Surgical System (Intuitive Surgical, Sunnyvale, CA) RMVR was performed. Details of the technique and patient's hospital course are described. The repair comprised closure of clefts between A3 and P3, quadrangular resection of P2, transfer of multiple chords from P2 to A2/A3 and a #38 Cosgrove-Edwards (Edwards Lifesciences, Irvine, CA) band annuloplasty. Nitinol U-Clips (Medtronic, Minneapolis, MN) were used to complete the annuloplasty. Postoperative TEE showed no mitral regurgitation. The patient was discharged on the third postoperative day. Cardiopulmonary bypass and arrested heart times were 3 hours and 29 minutes and 2 hours and 59 minutes, respectively. Complex bileaflet repair of mitral valve with Barlow's disease can be successfully performed with the da Vinci Robotic Surgical System. Long-term follow-up is needed to assess the durability of repair.

Papillary muscle repositioning for repair of anterior leaflet prolapse caused by chordal elongation

OBJECTIVE

Anterior leaflet prolapse is still a challenge. Various techniques have been described, but very little is known of the long-term outcome. We describe the long-term results of papillary muscle repositioning, with up to 15 years' follow-up.

METHODS

From 1989 through 2005, 120 patients with anterior leaflet prolapse (97 bileaflet and 23 isolated anterior leaflet) were treated with papillary muscle repositioning when chordae were elongated. All patients had severe mitral regurgitation. The mean left ventricular end-systolic diameter on echocardiography was 39.4 +/- 5.2 mm. The predominant cause was degenerative: dystrophic disease in 62 and Barlow's disease in 43. Papillary muscle repositioning was carried out on the posterior papillary muscle in 92.5% and on the anterior papillary muscle in 31.7%. A ring annuloplasty was performed in 117 cases. Fifty-seven (47.5%) patients had a tricuspid annuloplasty.

RESULTS

There were no in-hospital deaths or patients lost to follow-up. Mean follow-up was 6.3 +/- 0.4 years (maximum, 15.6 years). Cumulative actuarial survival at 5, 10, and 15 years was 97.2%, 94.1%, and 81.4%, respectively. Two (1.7%) patients required reoperation at 1 and 5 years after repair. No significant risk factor was identified for late mortality or reoperation. At the latest assessment, 88 (73.3%) patients were asymptomatic. Echocardiography showed no or trivial mitral regurgitation in 89 (74.2%) patients, mild mitral regurgitation in 8 patients, and moderate mitral regurgitation in 9 patients.

CONCLUSIONS

Anterior leaflet prolapse caused by elongated chordae can always be addressed with papillary muscle repositioning. Results indicate that it is a safe and durable technique, providing good long-term results in the management of degenerative pathology of the anterior leaflet.

Chordal plication and free edge remodeling for mitral anterior leaflet prolapse repair: 8-year follow-up

BACKGROUND

Chordal suture plication and free edge remodeling represent a personal technique for the repair of anterior leaflet prolapse. We report the results of an 8-year experience.

METHODS

Sixty-one patients with degenerative mitral regurgitation caused by prolapse of the anterior leaflet (11) or both leaflets (50) underwent anterior leaflet prolapse repair. Twenty patients who had associated cardiac procedures are included.

RESULTS

There were two perioperative deaths. Postoperative mitral regurgitation fell to 0.4 +/- 0.7 versus 3.7 +/- 0.4 preoperative (p < 0.0001). Mean follow-up was 40.5 months. There were 3 late deaths and 3 mitral reoperations (1 of 3 repairs, 2 of 3 replacements). Thromboembolism and endocarditis occurred in 1 patient each. Actuarial overall survival, freedom from cardiac death, and freedom from mitral reoperation at 92 months were 85.1% +/- 7.9%, 88.9% +/- 7.7%, and 94.6% +/- 3.0%, respectively.

CONCLUSIONS

Our technique of anterior leaflet prolapse repair appears effective, safe, and durable at mid- to long-term follow-up, and may be used in the presence of extensive disease of both leaflets.

Influence of anterior mitral leaflet second-order chordae on leaflet dynamics and valve competence

BACKGROUND

Chordal transposition is used in mitral valve repair, yet the effects of second-order chord transection on valve function have not been extensively studied. We evaluated leaflet coaptation, three-dimensional anterior mitral valve leaflet shape, and valve competence after cutting anterior second-order chordae.

METHODS

In 8 sheep radiopaque markers were affixed to the left ventricle, mitral annulus, and leaflets. Animals were studied immediately with biplane videofluoroscopy and echocardiography before (Control) and after (Cut2) severing two anterior second-order "strut" chordae. Leaflet coaptation was assessed as separation between leaflet edge markers in the midleaflet and near each commissure (anterior commissure, posterior commissure). Anterior leaflet geometry was determined 100 milliseconds after end-diastole from three-dimensional coordinates of 13 markers.

RESULTS

Anterior leaflet geometry changed only slightly after chordal transection without inducing mitral regurgitation. Leaflet coaptation times were 79+/-17 and 87+/-22 milliseconds at the anterior commissure; 72+/-21, 72+/-19 milliseconds at midleaflet, and 71+/-12 and 75+/-8 milliseconds at the posterior commissure (p = NS) for Control and Cut2, respectively.

CONCLUSIONS

Cutting anterior second-order chordae did not cause delayed leaflet coaptation, alter leaflet shape, or create mitral regurgitation. These data indicate that transposition of second-order anterior chordae ("strut" chordae) is not deleterious to anterior leaflet motion per se.