Long-term Assessment of Mitral Valve Reconstruction With Resection of the Leaflets: Triangular and Quadrangular Resection

Degenerative Mitral Valve Repair Simplified: An Evolution to Universal Artificial Cordal Repair

BACKGROUND

Resectional and artificial cordal repair techniques are effective strategies for degenerative mitral valve (MV) repair. However, resectional repair requires a tailored approach using various techniques, whereas cordal repair offers a simpler, easily reproducible repair. The approach described in this study approach has evolved from resectional to cordal over time, and outcomes are compared between the eras.

METHODS

Clinical and echocardiographic outcomes of all patients undergoing MV repair for degenerative mitral regurgitation (MR) from January 2004 to September 2017 were reviewed. Patients were stratified by era: from January 2004 to June 2011 (era 1; n = 405), resectional techniques were used in 62% and artificial cordal techniques were used in 38%. From July 2011 to September 2017 (era 2; n = 438), artificial cordal repair was used in 98% of patients. The primary outcome was repair failure, defined as greater than moderate MR or MV reoperation.

RESULTS

Of 847 patients with degenerative MR, successful repair was achieved in 843 patients (99.5% repair rate). Leaflet prolapse was posterior in 66%, anterior in 8%, and bileaflet in 26%. Cardiopulmonary bypass time and cross-clamp times were shorter in era 2 (CPB: 109 [IQR, 92-128] minutes vs 97 [IQR, 76-121] minutes; P < .001; cross-clamp: 88 [IQR, 73-106] minutes vs. 79 [IQR, 61-99] minutes; P < .001). Predismissal echocardiography demonstrated no MR or trace MR in 95%, mild MR in 4.7%, and moderate MR in 0.3% of patients. Operative mortality was similar in the eras (0.5% vs 0.5%; P > .999). The rates of 5-year freedom from repair failure (95.1% vs 95.5%; P = .707), stroke (96.8% vs 95.3%; P = .538), and endocarditis (99.3% vs 99.7%; P = .604) were similar between the eras.

CONCLUSIONS

Artificial cordal repair for all patients with degenerative MR simplifies MV repair and yields equivalent, excellent outcomes compared with a tailored resectional approach.

Chordal Reconstruction versus Leaflet Resection for Repair of Degenerative Posterior Mitral Leaflet Prolapse

OBJECTIVE

To review our experience of mitral valve repair for degenerative posterior mitral leaflet prolapse, comparing the outcomes of chordal reconstruction and leaflet resection.

METHODS

From 2000 to 2014, 205 patients underwent successful repair for degenerative posterior mitral leaflet prolapse. One hundred and four (51.5%) underwent leaflet resection (group R) and 98 (48.5%) underwent chordal reconstruction (group C). Follow-up was 96.5% complete with a mean follow-up of 6.1 ± 4.0 years.

RESULTS

Mean age was 57.0 ± 11.0 years. Males accounted for 73.8%. Ring annuloplasty was performed in 195 (96.5%). There were no operative mortalities within 30 days. Overall survival was 97.8% ± 1.3% at 7 years. Outcomes at 6 years: freedom from severe mitral regurgitation (group R 97.1% ± 2.0%, group C 100%, P = 0.288), freedom from moderate or severe mitral regurgitation (group R 97.1% ± 2.0%, group C 94.4% ± 5.4%, P = 0.541). Group C patients received larger annuloplasty rings and had significantly lower postoperative transmitral gradients.

CONCLUSIONS

Leaflet resection and chordal reconstruction are effective techniques for repair of degenerative posterior mitral leaflet prolapse. Both techniques result in a low incidence of recurrent mitral regurgitation. Chordal reconstruction accommodates larger annuloplasty rings and is associated with lower transmitral gradients.

Personalized Computational Modeling of Mitral Valve Prolapse: Virtual Leaflet Resection

Posterior leaflet prolapse following chordal elongation or rupture is one of the primary valvular diseases in patients with degenerative mitral valves (MVs). Quadrangular resection followed by ring annuloplasty is a reliable and reproducible surgical repair technique for treatment of posterior leaflet prolapse. Virtual MV repair simulation of leaflet resection in association with patient-specific 3D echocardiographic data can provide quantitative biomechanical and physiologic characteristics of pre- and post-resection MV function. We have developed a solid personalized computational simulation protocol to perform virtual MV repair using standard clinical guidelines of posterior leaflet resection with annuloplasty ring implantation. A virtual MV model was created using 3D echocardiographic data of a patient with posterior chordal rupture and severe mitral regurgitation. A quadrangle-shaped leaflet portion in the prolapsed posterior leaflet was removed, and virtual plication and suturing were performed. An annuloplasty ring of proper size was reconstructed and virtual ring annuloplasty was performed by superimposing the ring and the mitral annulus. Following the quadrangular resection and ring annuloplasty simulations, patient-specific annular motion and physiologic transvalvular pressure gradient were implemented and dynamic finite element simulation of MV function was performed. The pre-resection MV demonstrated a substantial lack of leaflet coaptation which directly correlated with the severe mitral regurgitation. Excessive stress concentration was found along the free marginal edge of the posterior leaflet involving the chordal rupture. Following the virtual resection and ring annuloplasty, the severity of the posterior leaflet prolapse markedly decreased. Excessive stress concentration disappeared over both anterior and posterior leaflets, and complete leaflet coaptation was effectively restored. This novel personalized virtual MV repair strategy has great potential to help with preoperative selection of the patient-specific optimal MV repair techniques, allow innovative surgical planning to expect improved efficacy of MV repair with more predictable outcomes, and ultimately provide more effective medical care for the patient.

Computational mitral valve evaluation and potential clinical applications

The mitral valve (MV) apparatus consists of the two asymmetric leaflets, the saddle-shaped annulus, the chordae tendineae, and the papillary muscles. MV function over the cardiac cycle involves complex interaction between the MV apparatus components for efficient blood circulation. Common diseases of the MV include valvular stenosis, regurgitation, and prolapse. MV repair is the most popular and most reliable surgical treatment for early MV pathology. One of the unsolved problems in MV repair is to predict the optimal repair strategy for each patient. Although experimental studies have provided valuable information to improve repair techniques, computational simulations are increasingly playing an important role in understanding the complex MV dynamics, particularly with the availability of patient-specific real-time imaging modalities. This work presents a review of computational simulation studies of MV function employing finite element structural analysis and fluid-structure interaction approach reported in the literature to date. More recent studies towards potential applications of computational simulation approaches in the assessment of valvular repair techniques and potential pre-surgical planning of repair strategies are also discussed. It is anticipated that further advancements in computational techniques combined with the next generations of clinical imaging modalities will enable physiologically more realistic simulations. Such advancement in imaging and computation will allow for patient-specific, disease-specific, and case-specific MV evaluation and virtual prediction of MV repair.

Three-dimensional echocardiography-based prediction of posterior leaflet resection

Clinical long-term outcomes have shown that partial leaflet resection followed by ring annuloplasty is a reliable and reproducible surgical repair technique for treatment of mitral valve (MV) leaflet prolapse. We report a 61-year-old male for three-dimensional transesophageal echocardiography (3DTEE)-based virtual posterior leaflet resection and ring annuloplasty. Severe mitral regurgitation was found and computational evaluation demonstrated substantial leaflet malcoaptation and high stress concentration. Following virtual resection and ring annuloplasty, posterior leaflet prolapse markedly decreased, sufficient leaflet coaptation was restored, and high stress concentration disappeared. Virtual MV repair strategies using 3DTEE have the potential to help optimize MV repair.

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.

Early outcomes of chordal reconstruction for posterior mitral leaflet prolapse

We retrospectively reviewed 16 patients (7 men and 9 women, aged 36 to 77 years) who underwent mitral valve repair with chordal reconstruction for isolated posterior mitral leaflet prolapse. Preoperative echocardiography demonstrated moderate mitral regurgitation in 1, and severe regurgitation in 15. We routinely used expanded polytetrafluoroethylene sutures as artificial chords, and ring annuloplasty was performed in all cases (mean ring size, 30 ± 2 mm). After implanting the ring, the length of the artificial chords was adjusted repeatedly using saline solution. Early postoperative echocardiography at 7.1 ± 1.1 days after surgery showed mitral regurgitation grades reduced to none or trivial in 15/16 patients. One required reoperation for recurrent mitral regurgitation 1.5 years after surgery. In the other patients, intermediate-term echocardiography at 9.1 ± 10.1 months after surgery demonstrated that residual mitral regurgitation was less than mild. We concluded that chordal reconstruction is an effective and highly reproducible procedure for the repair of isolated posterior mitral leaflet prolapse. Artificial chords for the posterior mitral leaflet should not be too long, to avoid systolic anterior motion or recurrent mitral regurgitation after surgery.

Mitral Valve Repair: Past, Present, and Future

Mitral valve repair is the operation of choice for mitral valve regurgitation, with appropriate selection. Studies have shown that mitral repair is associated with a decrease in both long-term thromboembolic complications and mortality. Since its initial description, various selection criteria and techniques of mitral valve repair have been discussed in the literature. This review serves as a synopsis of the previous achievements, present status, and possible future directions of mitral valve repair, specifically from an Asian perspective. Vast experience has been amassed in understanding mitral valve pathophysiology, and excellent surgical treatments for mitral regurgitation have been developed. With the efforts of pioneers in the field of mitral valve repair, standard surgical treatment strategies have been proven to restore the life-expectancy of patients with degenerative mitral regurgitation to that of the age-adjusted population. Minimally invasive techniques of mitral valve repair further reduce access trauma, and could potentially benefit patients previously excluded from conventional surgery.

Beginning and development of surgery for acquired valvular heart disease in Japan

The initiation and development of surgery for acquired valvular heart disease in Japan was reviewed. The first series of attempts at closed valvular surgery were performed in 1951-1952 by collaboration between the brothers Tohru and Shigeru Sakakibara in patients with pulmonary or mitral stenosis. During the popularization of closed valvular surgery, open heart surgery under direct vision was successfully performed by Shigeru Sakakibara with cooling of the body in 1954 and by using cardiopulmonary bypass (CPB) in 1956. With the development of CPB and artificial heart valves, closed valvular heart surgery was replaced by open surgery, which expanded rapidly during the 1960s and 1970s. Along with the serial introduction and improvement of mechanical vales thereafter, bioprosthetic valves were also introduced and were adopted for certain patients. Use of bioprosthetic valves in the aortic position exceeded 50% in 2005, along with the increase of elderly patients. Although trials of mitral valve plasty for mitral regurgitation were first done during the 1950s to 1960s in Japan, interest in valve plasty only increased during the late 1970s. Considering the patient's quality of life and the long-term results, mitral valve plasty became the major procedure (exceeding valve replacement) from 2004. In 2002, the Guideline for Surgical and Interventional Treatment of Valvular Heart Disease was published by a joint committee of the relevant academic societies, and it has made an important contribution to improving surgical outcomes.

A Simplified Approach to Degenerative Disease: Triangular Resections of the Mitral Valve

BACKGROUND

Only 40% of patients with mitral valve (MV) regurgitation undergo operative repair rather than replacement. Quadrangular resection combined with ring annuloplasty has been the most common method of repair for degenerative posterior leaflet disease. Techniques such as sliding annuloplasty and artificial chord usage have increased the complexity of repair. These techniques have been perceived to be difficult and have possibly reduced the incidence of MV repair. We present our experience with a simplified approach to MV repair utilizing a triangular resection and larger rings.

METHODS

Retrospective review of all MV repairs over a 7-year period (1999 to 2006) revealed 154 patients who underwent triangular resection for degenerative disease. Patients who underwent ring annuloplasty without leaflet resection and patients who had artificial chords or quadrangular resections were excluded.

RESULTS

Of 154 patients who underwent triangular resection, isolated posterior leaflet resection was performed on 130 patients. Isolated anterior and combined anterior and posterior leaflet triangular resections were performed on 16 and 8 patients, respectively. Thirty-day postoperative mortality was 0%. Five-year freedom from reoperation for recurrent mitral regurgitation was 99.0%. No patients who had intended leaflet resection were converted to MV replacement. Intraoperative transesophageal echocardiogram revealed trace to 1+ mitral regurgitation. Mild systolic anterior motion was noted in 7.1% of cases initially, but resolved with volume loading in all.

CONCLUSIONS

Triangular leaflet resection of the mitral valve produces durable results and can be safely and efficiently performed with minimal morbidity and mortality. This technique should allow increased utilization of MV repair for degenerative disease.

Mitral valve repair for degenerative mitral regurgitation

Mitral valve repair for degenerative mitral regurgitation is nowadays one of the most common valvular procedures. Different technical modifications were added to the original Carpentier's method, trying to maximise the stability of the results and to reduce the incidence of immediate complications and of late failure of the correction. Survival is good, even if recent reports showed that recurrence of mitral regurgitation can be higher than expected. Prolapse of the anterior leaflet remains challenging and is related to higher reintervention rates. Nevertheless, the overall success rate is high, and the increasing experience of the different surgical teams approaching this procedure will help maintain satisfactory and stable long-term results.

Midterm results of mitral valve repair with the Carpentier-Edwards rigid ring

OBJECTIVE

Prosthetic annuloplasty rings play an important role in mitral valve repair. This clinical study was undertaken to evaluate the midterm results obtained with the Carpentier-Edwards rigid ring.

METHODS

Between October 1991 and March 2005, 112 patients (mean age 53.0 years) underwent mitral valve repair with a Carpentier-Edwards rigid ring at our institution. Degenerative disease was the most frequent cause and a small number had other conditions such as endocarditis and rheumatic disease. Ten patients were in Carpentier's functional class Type I, 101 patients in Type II and 1 patient in Type III, based on valve pathology. Ischemic mitral regurgitation was excluded. The mean follow-up time was 5.3+/-3.6 years (range: 8 days to 12.3 years). All patients were completely followed by echocardiography.

RESULTS

The rigid ring ranged from 26 to 36 mm in diameter and the most common size was 30 mm. Although the mitral orifice area was decreased after mitral valve repair in all patients, none of them required reoperation because of mitral stenosis or left ventricular outflow tract obstruction (systolic anterior motion). Reduction of both systolic and diastolic left ventricular volumes was observed postoperatively. Ejection fractions were preserved in all cases. The actuarial survival rate was 92.0+/-3.0% at 10 years and the reoperation-free rate at 10 years was 96.0+/-2.0%.

CONCLUSION

The rigid ring has produced promising midterm results in terms of reoperation-free and survival rates.