Impact of a preoperative mitral regurgitation scoring system on outcome of surgical repair for mitral valve prolapse

Cardiac magnetic resonance imaging in the evaluation and management of mitral valve prolapse - a comprehensive review

Mitral valve prolapse is a common valve disorder that usually has a benign prognosis unless there is significant regurgitation or LV impairment. However, a subset of patients are at an increased risk of ventricular arrhythmias and sudden cardiac death, which has led to the recognition of "arrhythmic mitral valve prolapse" as a clinical entity. Emerging risk factors include mitral annular disjunction and myocardial fibrosis. While echocardiography remains the primary method of evaluation, cardiac magnetic resonance has become crucial in managing this condition. Cine magnetic resonance sequences provide accurate characterization of prolapse and annular disjunction, assessment of ventricular volumes and function, identification of early dysfunction and remodeling, and quantitative assessment of mitral regurgitation when integrated with flow imaging. However, the unique strength of magnetic resonance lies in its ability to identify tissue changes. T1 mapping sequences identify diffuse fibrosis, in turn related to early ventricular dysfunction and remodeling. Late gadolinium enhancement sequences detect replacement fibrosis, an independent risk factor for ventricular arrhythmias and sudden cardiac death. There are consensus documents and reviews on the use of cardiac magnetic resonance specifically in arrhythmic mitral valve prolapse. However, in this article, we propose an algorithm for the broader use of cardiac magnetic resonance in managing this condition in various scenarios. Future advancements may involve implementing techniques for tissue characterization and flow analysis, such as 4D flow imaging, to identify patients with ventricular dysfunction and remodeling, increased arrhythmic risk, and more accurate grading of mitral regurgitation, ultimately benefiting patient selection for surgical therapy.

A complexity evaluation system for mitral valve repair based on preoperative echocardiographic and machine learning

BACKGROUND

To develop a novel complexity evaluation system for mitral valve repair based on preoperative echocardiographic data and multiple machine learning algorithms.

METHODS

From March 2021 to March 2023, 231 consecutive patients underwent mitral valve repair. Clinical and echocardiographic data were included in the analysis. The end points included immediate mitral valve repair failure (mitral replacement secondary to mitral repair failure) and recurrence regurgitation (moderate or greater mitral regurgitation [MR] before discharge). Various machine learning algorithms were used to establish the complexity evaluation system.

RESULTS

A total of 231 patients were included in this study; the median ejection fraction was 66% (63-70%), and 159 (68.8%) patients were men. Mitral repair was successful in 90.9% (210 of 231) of patients. The linear support vector classification model has the best prediction results in training and test cohorts and the variables of age, A2 lesions, leaflet height, MR grades, and so on were risk factors for failure of mitral valve repair.

CONCLUSION

The linear support vector classification prediction model may allow the evaluation of the complexity of mitral valve repair. Age, A2 lesions, leaflet height, MR grades, and so on may be associated with mitral repair failure.

Mitral valve regurgitation and 3D echocardiography

The mitral valve is a complex, dynamic and functional apparatus that can be altered by a wide range of disorders leading to stenosis or regurgitation. Surgical management of mitral valve disease may be difficult. Planned intervention may not always be feasible when the surgeon is faced with complex pathology that cannot be assessed fully by conventional 2D echocardiography. Transthoracic and transesophageal 3D echocardiography can provide a more reliable functional and anatomical assessment of the different valve components and evaluation of its geometry, which can aid the surgeon in planning a more suitable surgical intervention and improve outcomes. Although 3D echocardiography is a new technology, it has proven to be an important modality for the accurate assessment of valvular heart disease and in the future, it promises to be an essential part in the routine assessment of cardiovascular patients.

Outcome of Watchful Waiting in Asymptomatic Severe Mitral Regurgitation

Background— The management of asymptomatic severe mitral regurgitation remains controversial. The aim of this study was to evaluate the outcome of a watchful waiting strategy in which patients are referred to surgery when symptoms occur or when asymptomatic patients develop left ventricular (LV) enlargement, LV dysfunction, pulmonary hypertension, or recurrent atrial fibrillation.

Methods and Results— A total of 132 consecutive asymptomatic patients (age 55±15 years, 49 female) with severe degenerative mitral regurgitation (flail leaflet or valve prolapse) were prospectively followed up for 62±26 months. Patients underwent serial clinical and echocardiographic examinations and were referred for surgery when the criteria mentioned above were fulfilled. Overall survival was not statistically different from expected survival either in the total group or in the subgroup of patients with flail leaflet. Eight deaths were observed. Thirty-eight patients developed criteria for surgery (symptoms, 24; LV criteria, 9; pulmonary hypertension or atrial fibrillation, 5). Survival free of any indication for surgery was 92±2% at 2 years, 78±4% at 4 years, 65±5% at 6 years, and 55±6% at 8 years. Patients with flail leaflet tended to develop criteria for surgery slightly but not significantly earlier. There was no operative mortality. Postoperative outcome was good with regard to survival, symptomatic status, and postoperative LV function.

Conclusions— Asymptomatic patients with severe degenerative mitral regurgitation can be safely followed up until either symptoms occur or currently recommended cutoff values for LV size, LV function, or pulmonary hypertension are reached. This management strategy is associated with good perioperative and postoperative outcome but requires careful follow-up.

Risk factors of posterior pericardial annuloplasty for isolated posterior leaflet prolapse

BACKGROUND

Posterior autologous pericardial annuloplasty is an option in mitral valve repair. However, the durability of posterior pericardial annuloplasty remains controversial.

METHODS

From June 1999 to July 2004, 49 patients (18 male and 31 female; mean age, 64 +/- 12 years) with isolated posterior leaflet prolapse received posterior autologous pericardial annuloplasty. Transthoracic echocardiographic examination before the operation, at the time of discharge, and then annually was performed and analyzed.

RESULTS

There was no incidence of in-hospital or late death. Only 1 patient (2.1%) required reoperation. In terms of recurrent mitral regurgitation, 31 patients (64.6%) exhibited grade 0 mitral regurgitation, 7 patients (14.6%) exhibited grade 1, and 9 patients (18.8%) exhibited grade 2, whereas only 1 patient (2.0%) exhibited more than grade 3. In terms of predicting postoperative recurrence of significant mitral regurgitation (> or =grade 2), multivariate Cox analysis demonstrated that marked left atrial dilatation and high fractional shortening were independent risk factors. In 8 of 10 patients significant mitral regurgitation recurred after discharge. In terms of left atrial dimension, no significant reduction was observed in the postdischarge recurrent group, and there was a significant difference of left atrial dimension between the postdischarge recurrent group and the nonrecurrent group at the time of discharge.

CONCLUSIONS

The merits of mitral valve repair using posterior autologous pericardial annuloplasty are attractive. However, its use should be limited in selected patients with isolated posterior leaflet disease, nonenlarged atria, and non-high fractional shortening to maintain the durability of the mitral valve repair.

Development of a new animal model of chronic mitral regurgitation in rats under transesophageal echocardiographic guidance

Large animal models (dog and sheep) are often used for the investigation of the pathophysiology of chronic mitral regurgitation (MR). A major limitation of large animal models is cost. The aim of this study was to develop a new animal model of chronic MR. Left thoracotomy was performed in 34 rats. Under the guidance of transesophageal echocardiography, a fine needle was inserted into the left ventricle (LV) to damage the mitral leaflets and produce MR. Serial transthoracic echocardiography was performed to assess LV remodeling and function. Left atrial and LV diameters were significantly larger, and LV fractional shortening was lower in the MR group than in the sham group. The 150-day survival was 59% in the MR group and 100% in the sham group (P < .01). This new animal model of chronic MR may be used in the study of the pathophysiology of chronic MR and pharmacologic therapies.

Pre-operative atrial fibrillation as the key determinant of outcome of mitral valve repair for degenerative mitral regurgitation

AIMS

To examine the impact of pre-operative atrial fibrillation (AF) on the outcome of mitral valve repair (MVR) for degenerative mitral regurgitation (MR).

METHODS AND RESULTS

Among 392 patients with moderate to severe MR who underwent MVR between 1991 and 2002, 283 patients with isolated degenerative MR were followed for 4.7+/-3.3 years. Of 27 deaths, nine were due to cardioembolic events and four were due to left ventricular (LV) dysfunction. When compared with patients with pre-operative AF, those with sinus rhythm (SR) had better survival (96+/-2.1 vs. 87+/-3.2% at 5 years, P=0.002) and higher cardiac event-free rates (96+/-2.0 vs. 75+/-4.4% at 5 years, P<0.001). In patients with pre-operative SR, observed and expected survival were similar (P=0.811). Cox multivariable regression analysis confirmed AF [P=0.027, adjusted hazard ratio (AHR) 2.9] and age as independently predictive of survival, and AF (P=0.002, AHR 3.1), New York Heart Association Class, and LV fractional shortening as independently predictive of cardiac event.

CONCLUSION

Death due to LV dysfunction was not frequent and cardioembolic events due to AF were the leading cause for cardiac death. Pre-operative AF became a strong independent predictor of survival and morbidity. Patients with pre-operative SR had excellent prognosis. The benefits of preventing cardioembolic events due to AF validate the indication of MVR for patients with high risk for AF.