Choosing the “Best” surgical techniques for mitral valve repair: Lessons from the literature

Image-Based Computational Fluid Dynamics to Compare Two Repair Techniques for Mitral Valve Prolapse

OBJECTIVE : The treatment of mitral valve prolapse involves two distinct repair techniques: chordal replacement (Neochordae technique) and leaflet resection (Resection technique). However, there is still a debate in the literature about which is the optimal one. In this context, we performed an image-based computational fluid dynamic study to evaluate blood dynamics in the two surgical techniques. METHODS : We considered a healthy subject (H) and two patients (N and R) who underwent surgery for prolapse of the posterior leaflet and were operated with the Neochordae and Resection technique, respectively. Computational Fluid Dynamics (CFD) was employed with prescribed motion of the entire left heart coming from cine-MRI images, with a Large Eddy Simulation model to describe the transition to turbulence and a resistive method for managing valve dynamics. We created three different virtual scenarios where the operated mitral valves were inserted in the same left heart geometry of the healthy subject to study the differences attributed only to the two techniques. RESULTS : We compared the three scenarios by quantitatively analyzing ventricular velocity patterns and pressures, transition to turbulence, and the ventricle ability to prevent thrombi formation. From these results, we found that the operative techniques affected the ventricular blood dynamics in different ways, with variations attributed to the reduced mobility of the Resection posterior leaflet. Specifically, the Resection technique resulted in turbulent forces, related with the risk of hemolysis formation, up to 640 Pa, while the other two scenarios exhibited a maximum of 240 Pa. Moreover, in correspondence of the ventricular apex, the Resection technique reduced the areas with low velocity to 15%, whereas the healthy case and the Neochordae case maintained these areas at 30 and 48%, respectively. Our findings suggest that the Neochordae technique developed a more physiological flow with respect to the Resection technique. CONCLUSION: Resection technique gives rise to a different direction of the mitral jet during diastole increasing the ability to washout the ventricular apex preventing from thrombi formation, but at the same time it promotes turbulence formation that is associated with ventricular effort and risk of hemolysis.

Application of a Novel Mitral Valvuloplasty Strategy in Children with Mitral Regurgitation

To retrospectively analyze the clinical efficacy of an innovative mitral valvuloplasty strategy in the treatment of mitral regurgitation in children. From January 2018 to December 2022, 140 patients undergoing surgical treatment for mitral regurgitation in our hospital were enrolled. Ninety patients underwent three-step standardized pediatric mitral valvuloplasty (group A) and 50 patients underwent simple annuloplasty (group B). The incidence of primary and secondary study endpoint was compared between the two groups, and the independent risk factors for the primary study endpoint were determined. Our primary study endpoint was a composite endpoint of postoperative functional mitral failure, postoperative heart failure, transplantation, and/or mortality. Secondary end points were defined as perioperative complications. During the follow-up period, there was no all-cause death. Primary endpoint events occurred in 22 patients, including 12 patients in group A and 10 patients in group B. There was no significant difference in the incidence of primary and secondary endpoint events between the two groups. Multivariate Cox proportional hazards regression analysis showed that younger age and residual mitral regurgitation at discharge were independent risk factors for the primary endpoint events, while type of MV repair was not an independent risk factor. Subgroup analysis based on age showed that primary endpoint events occurred in 4 patients in group A and 7 patients in group B in patients < 1 year old. The incidence of primary endpoint events in group A was lower than that in group B (6.06% vs. 20.59%, P = 0.041). In patients ≥ 1 year old, the primary endpoint event occurred in 8 cases in group A and 3 cases in group B. There was no significant difference in the incidence of primary endpoint events between groups A and B (33.33% vs. 18.75%, P = 0.312). The degree of mitral regurgitation at discharge was significantly improved compared with that before operation in both groups (P < 0.001), and the degree of mitral regurgitation at the last follow-up was not significantly worse than that at discharge (P = 0.090). The mid-term results of mitral valvuloplasty for mitral regurgitation in children are encouraging. The perioperative recovery and postoperative outcomes of three-step standardized mitral valvuloplasty in children are not inferior to those of annuloplasty alone. Three-step standardized pediatric mitral valvuloplasty has better postoperative outcomes than simple mitral annuloplasty, especially for patients younger than 1 year old. Children with residual mitral regurgitation at discharge should be followed up regularly to be alert to the occurrence of poor prognosis.

Mitral Valve Repair of the Anterior Leaflet: Are We There Yet?

Mitral regurgitation is one of the most prevalent valvulopathies with a disease burden that incurs significant healthcare costs globally. Surgical repair of the posterior mitral valve leaflet is a standard treatment, but approaches for repairing the anterior mitral valve leaflet are not widely established. Since anterior leaflet involvement is less common and more difficult to repair, fewer studies have investigated its natural history and treatment options. In this review, we discuss surgical techniques for repairing the anterior leaflet and their outcomes, including survival, reoperation, and recurrence of regurgitation. We show that most patients with mitral regurgitation from the anterior leaflet can be repaired with good outcomes if performed at centers with expertise. Additionally, equal consideration for early repair should be given to patients with mitral regurgitation from both anterior and posterior pathology. However, more studies to better evaluate the efficacy and safety of anterior mitral valve leaflet repair are needed.

Respect or resect in Barlow disease

Mitral regurgitation in Barlow disease may still be challenging to be repaired. Most often it involves the posterior leaflet. Many techniques and concepts are currently available; the main goal being to restore a good surface of coaptation. Basic principles such as thorough analysis is still required whatever the approach to assess excess tissue height, width, and prolapse. Nowadays it seems that two different ways of treating mitral prolapse coexist: the nonresection one and the resection one. Both will be discussed and analyzed. Similarly, the use of artificial chordae seems to have a preponderant role to support the free edge and correct a prolapse. Native secondary chord transfer are easy and reliable but seem abandoned by many. Anterior leaflet prolapse is also dealt with and fewer options are available to address this leaflet. Then commissural prolapse is mentioned. It is an important area of the valve which should deserve better treatment than commissuroplasty. Finally, a special entity will be described; mitro annular disjunction. The approach is not or no longer an issue as only good long-term results are important in an era where percutaneous therapy is the only noninvasive technique.

Echocardiographic characteristics of non-resectional ring-only valve repair in mitral valve prolapse

BACKGROUND

Simple mitral valve repair (MVR) using a ring-only approach (ROA) was recently proposed for some complex forms of bileaflet myxomatous mitral valve prolapse (MVP). Nevertheless, few data are available concerning the characteristics of MVP patients that may benefit from this simple repair technique.

METHODS

Based on 39 consecutive patients (28 men; mean age 57 ± 15) with severe primary Mitral regurgitation (MR) caused by bileaflet MVP referred for MVR, we sought to identify the preoperative echocardiographic parameters associated with successful ROA repair.

RESULTS

Twenty-three patients (59%) underwent standard resectional MVR (SMVR) while 16 (41%) underwent ROA. Cardiopulmonary bypass and cross clamp times were lower in ROA than in SMVR (74 ± 27 min vs 99 ± 42 min and 49 ± 19 min vs 70 ± 25 min, respectively, p = 0.03 and p = 0.005). ROA patients were more frequently women (50% vs 13%, p = 0.027). Echocardiographic characteristics of successful ROA were mid-late systolic MR, a paradoxical systolic papillary muscle displacement, and paradoxical systolic annulus expansion (PAE). A prolapsing depth <10 mm, the absence of flail leaflet and ruptured chordae, the presence of multiple jets, more often in the central part of the valve were also associated with ROA. Non hemodynamic systolic anterior motion and residual trivial MR tended to be more frequent in ROA than in SMVR.

CONCLUSION

Simple and fast MVR using a ROA is feasible in 4/10 patients with complex forms of bileaflet MVP. Successful ROA patients were more frequently women, with mid-late systolic central multiple jet, low prolapse depth, absence of chordal rupture or flail leaflet and PAE.

Mitral Annular Forces and Their Potential Impact on Annuloplasty Ring Selection

Objectives: To provide an overview that describes the characteristics of a mitral annuloplasty device when treating patients with a specific type of mitral regurgitation according to Carpentier's classification of mitral regurgitation.

Methods: Starting with the key search term “mitral valve annuloplasty,” a literature search was performed utilising PubMed, Google Scholar, and Web of Science to identify relevant studies. A systematic approach was used to assess all publications.

Results: Mitral annuloplasty rings are traditionally categorised by their mechanical compliance in rigid-, semi-rigid-, and flexible rings. There is a direct correlation between remodelling capabilities and rigidity. Thus, a rigid annuloplasty ring will have the highest remodelling capability, while a flexible ring will have the lowest. Rigid- and semi-rigid rings can furthermore be divided into flat and saddled-shaped rings. Saddle-shaped rings are generally preferred over flat rings since they decrease annular and leaflet stress accumulation and provide superior leaflet coaptation. Finally, mitral annuloplasty rings can either be complete or partial.

Conclusions: A downsized rigid- or semi-rigid ring is advantageous when higher remodelling capabilities are required to correct dilation of the mitral annulus, as seen in type I, type IIIa, and type IIIb mitral regurgitation. In type II mitral regurgitation, a normosized flexible ring might be sufficient and allow for a more physiological repair since there is no annular dilatation, which diminishes the need for remodelling capabilities. However, mitral annuloplasty ring selection should always be based on the specific morphology in each patient.

Results after Repair of Functional Tricuspid Regurgitation with a Three-Dimensional Annuloplasty Ring

Background: Tricuspid valve (TV) repair is the recommended treatment for severe functional tricuspid regurgitation (fTR) in patients undergoing left-sided surgery. For this purpose, a wide range of annuloplasty devices differing in form and flexibility are available. This study reports the results using a three-dimensional annuloplasty ring (Medtronic, Contour 3D Ring) for TV repair and analysis of risk factors. Methods: A cohort of 468 patients who underwent TV repair (TVr) with a concomitant cardiac procedure from December 2010 to January 2017 was retrospectively analyzed. Results: At follow-up, 96.1% of patients had no/trivial or mild TR. The 30-day mortality was 4.7%; it significantly differed between electively performed operations (2.7%) and urgent/emergent operations (11.7%). Risk factors for recurrent moderate and severe TR were LVEF < 50%, TAPSE < 16 mm, and moderate mitral valve (MV) regurgitation at follow-up. Preoperatively reduced renal function lead to a higher 30-day and overall mortality. Reoperation of the TV was required in six patients (1.6%). Risk factors for TV related reoperations were preoperative TV annulus over 50 mm and an implanted permanent pacemaker. Conclusions: TVr with the Contour 3D annuloplasty ring shows low TR recurrence and reoperation rates. Risk-factor analysis for the recurrence of TR revealed the importance of left- and right-ventricular function.

Clinico-pathological classification of rheumatic mitral valve damage and surgical strategy

Background

There is a lack of established pathological indications for rheumatic valve repair. Therefore, we summarized the pathological classifications of rheumatic heart diseases and their correlations with the surgical strategies.

Methods

This observational study enrolled patients with rheumatic heart diseases who underwent mitral valve repair (MVP) or replacement at our centre between January 2017 and January 2019. Mitral leaflet, mitral commissural, and sub-valvular apparatus were classified into three grades from mild to severe, according to their degree of pathological damage. Based on certain principles and the grade of mitral leaflet, mitral commissural, and sub-valvular apparatus damage, three pathological types were identified (types I to III), based on which all patients were classified. The features of each pathological type were summarised. Differences between the three pathological types were analysed using chi-square test of tendency. These data were used to propose a clinico-pathological classification of rheumatic mitral valve damage in Chinese patients.

Results

Of 398 patients, 284 (70%) underwent MVP for rheumatic mitral valve diseases. There were 58 type I (15%) patients in the study, all of whom underwent repair (repair rate, 100%). Preoperative moderate-to-severe regurgitation with mild pathological lesions was observed in 64% of these patients. In 260 type II (65%) patients, the repair rate was 76% (197/260); preoperative moderate-to-severe stenosis was observed in 88% of these patients. In 80 type III (20%) patients, the repair rate was 36% (29/80); the preoperative rates of extremely severe stenosis and moderate-to-severe regurgitation in these patients were 50% and 40%, respectively. Several preoperative parameters show the change in trend with the increase in the pathological classification severity.

Conclusions

Our clinico-pathological classification of rheumatic mitral valve damage is applicable to MVP. Considering that the classification principles are based on the possibility of mitral repair, it provides a phased and achievable target ratio for MVP and a principle of screening patients who should undergo rheumatic MVP.

Minimally Invasive Mitral Surgery: Patient Selection and Technique

In most patients, minimally invasive approaches to mitral valve surgery are technically possible. However, in practice, patient selection is critical to mitigate safety concerns when performing the procedure. In this article, we describe our approach to preoperative assessment for minimally invasive mitral valve surgery candidacy, as well as discussing the technical aspects of procedure execution.

Early failure after non-resectional mitral valve repair with artificial chordae

Severe recurrent mitral regurgitation within 1 year of mitral valve repair is usually attributed to a technical issue with the original repair procedure. However, when artificial chordae are employed to correct mitral valve prolapse, ventricular remodeling (ie, decreased ventricular size) can lead to recurrent prolapse and valve dysfunction. To illustrate this phenomenon, we present two patients who experienced early failure after undergoing mitral valve repair with artificial chordae.

Early outcomes of mitral valvuloplasty by minimally invasive surgery or sternotomy

BACKGROUND

Disagreement exists regarding methods for repair of the mitral valve. We compared early outcomes of mitral valvuloplasty by a minimally invasive technique and by a median sternotomy.

METHODS

The data of 507 patients (mean age 47.9 ± 15.2 years) undergoing mitral valvuloplasty from January 2015 to June 2018 were analyzed retrospectively. In the study group (n = 225), mitral valvuloplasty via a totally thoracoscopic approach was performed by a single surgeon. In the control group (n = 282), mitral valvuloplasty via the traditional median sternotomy was carried out by other cardiac surgeons in our hospital. Clinical data, surgical results, and follow-up findings in the two groups were comparatively analyzed.

RESULTS

In the study group, the blood transfusion rate (5.3% vs. 20.9%, p < 0.05) and incidences of poor wound healing (0 vs. 5.3%, p < 0.05) and respiratory tract infection (4.4% vs. 16.3%, p < 0.05) were lower, and postoperative hospitalization was shorter (5.9 ± 4.0 vs. 10.7 ± 8.4 days, p < 0.05). Within 30 days after surgery, no patient died in the study group while one died in the control group. The duration of follow-up was 12-36 months (mean 22.9 ± 8.8 months). During follow-up, there were 1 and 0 cases of redo surgery and 1 and 3 deaths in the study group and control group, respectively.

CONCLUSION

Mitral valvuloplasty via a minimally invasive approach is superior to the traditional median sternotomy in terms of early outcomes, especially when performed by experienced surgeons.