Cleft posterior mitral valve leaflet associated with counterclockwise papillary muscle malrotation

Cleft posterior mitral valve leaflet: The added value of 3-dimensional echocardiography

A 65-year-old female patient diagnosed with degenerative aortic valve disease and severe regurgitation on transthoracic echocardiography (TTE) also had severe mitral regurgitation (MR), but the exact mechanism of MR could not be determined. Transesophageal echocardiography (TEE) showed limited leaflet coaptation and a severe central MR jet. Further three-dimensional (3D) imaging revealed an indentation in the middle of P2 scallop almost reaching the annulus. This was consistent with the diagnosis of cleft posterior mitral valve leaflet. Unlike cleft anterior leaflet which can be clear on TTE short-axis images, cleft posterior leaflet may only be visible using 3D TEE. The identification of cleft posterior leaflet is essential in guiding surgical valve repair.

Diagnosis of Isolated Cleft Mitral Valve Using Three-Dimensional Echocardiography

BACKGROUND

The prevalence of isolated cleft mitral valve (MV; no concomitant congenital heart disease or degenerative MV disease) with significant mitral regurgitation (MR) diagnosed using two-dimensional echocardiography (2DE) has been reported to be very low. Three-dimensional echocardiography (3DE) has enabled a more comprehensive visualization of the MV and detailed understanding of the mechanisms of MR and can potentially reveal isolated cleft MV that is not recognized with 2DE. The aim of this study was to determine, using 3DE, the prevalence, location, and associated MV annular and left ventricular characteristics of isolated cleft MV, in the absence of associated congenital heart disease, in patients with significant MR.

METHODS

A total of 1,092 patients with unexplained moderate or greater MR on two-dimensional transthoracic echocardiography who were referred for three-dimensional transesophageal echocardiography between 2005 and 2017 (n = 626) were retrospectively studied. Left ventricular dimensions and function were determined, and quantitative MR assessment and three-dimensional analysis of the MV annulus was performed.

RESULTS

Twenty-one patients (prevalence 3.3%) were diagnosed with isolated cleft MV using three-dimensional transesophageal echocardiography but not 2DE. The majority of these patients (n = 16) were noted to have anterior cleft MVs, with most located in the mid-A1 (n = 10) or mid-A3 (n = 5) scallops. Posterior clefts were less common (n = 5) and occurred at the site of the natural scallop indentations (three between P1 and P2 and two between P2 and P3). Among patients with either anterior or posterior MV cleft, there were no differences in left ventricular ejection fraction or three-dimensional MV geometry (annular distance, height, circumference, and area). There was a trend toward worse MR severity in patients with anterior cleft MV.

CONCLUSIONS

In patients with otherwise unexplained significant MR referred for transesophageal echocardiography, 3DE uncovered a considerably higher prevalence of isolated cleft MV than previously reported by 2DE, with the majority located in the anterior MV. Although the annular geometry was similar between patients with anterior and posterior cleft MVs, a trend toward more severe MR in anterior clefts may reflect underlying abnormalities in the embryologic development of the anterior MV leaflet. Evaluation of MV pathology is improved by 3DE, which should be used routinely in the setting significant MR.

The Trileaflet Mitral Valve

With the advent of 3-dimensional echocardiography, visualization of the mitral valve has greatly improved. Recently, there has been an increase in reporting of a distinct entity called the "trileaflet mitral valve" using 3-dimensional echocardiography. It is controversial whether this is a new entity or an improved visualization of isolated mitral valve clefts or trifoliate left atrioventricular valve in the setting of an atrioventricular septal defect (AVSD) with intact septum. We present a case of a trifoliate valve, interpreting our findings based on a systematic review of previous publication on trileaflet mitral valves, isolated clefts in the mural (posterior) leaflet of the mitral valve, and trifoliate left atrioventricular valves with AVSD and intact septal structures. We describe the latter entity as a left atrioventricular valve because it never achieves the features of a normal mitral valve. We compare the features of isolated clefts of the mural leaflet of the mitral valve with trifoliate left atrioventricular valve found in the setting of AVSDs with intact septal structures to illustrate the current controversy regarding these conditions. In conclusion, our review suggested the reported trileaflet left atrioventricular valves is likely a misnomer because of a lack of consideration of embryologic development and nomenclature, rather than a greater appreciation and identification of a new distinct disease entity.

Diagnosis of mitral valve cleft using real-time 3-dimensional echocardiography

BACKGROUND

Mitral valve cleft (MVC) is the most common cause of congenital mitral insufficiency, and MVC may occur alone or in association with other congenital heart lesions. Direct suture and valvuloplasty are the major and effective treatments for mitral regurgitation (MR) caused by MVC. Therefore, it is important to determine the location and magnitude of the pathological damage due to MVC when selecting a surgical procedure for treatment. This study explored the application value of transthoracic real-time 3-dimensional (3D) echocardiography (RT-3DE) in the diagnosis of MVC.

METHODS

From October 2012 to June 2016, 19 consecutive patients with MVC diagnosed by 2-dimensional (2D) echocardiography in our hospital were selected for this study. Full-volume RT-3DE was performed on all patients. The 3D-imaging data were cropped and rotated in 3 views (horizontal, sagittal, and coronal) with 6 directions to observe the position and shape of the MVC and the spatial position between the cleft and its surrounding structures. The maximum longitudinal diameter and the maximum width of the cleft were measured. The origin of the mitral regurgitant jet and the severity of MR were evaluated, and these RT-3DE data were compared with the intraoperative findings.

RESULTS

Of the 19 patients studied, 4 patients had isolated cleft mitral valve, and cleft mitral valves combined with other congenital heart lesions were detected in 15 patients. The clefts of 6 patients were located in the A2 segment, the clefts of 4 patients were located in the A1 segment, the clefts of 4 patients were located in the A3 segment, the clefts of 4 patients were located in the A2-A3 segment, and the cleft of 1 patient was located in the P2 segment. Regarding the shape of the cleft, 13 patients had V-shaped clefts, and the others had C- or S-shaped clefts. The severity of the MR at presentation was mild in 2 patients, moderate in 9 and severe in 8. Two of the patients with mild MR did not undergo surgery, while the remaining 17 patients did undergo surgery. Surgical treatment involved direct suture in 11 cases, reconstruction with ring annuloplasty in 3 cases and replacement in 3 cases. The diagnoses of MVC were confirmed by intraoperative findings. RT-3DE successfully captured full-volume 3D images of the 19 patients, which directly displayed the 3D structure of MVC with multiple views such as the position, shape, longitudinal diameter and width of the MVC, and the spatial position between the chordae tendineae surrounding the MVC and the aortic valve. The maximum longitudinal diameter of the valve leaflet cleft measured by RT-3DE and direct measurements during surgery were 12.02±2.12 and 13.01±2.45 mm, respectively, and the difference between these measurements was not statistically significant (P>0.05). Our results indicate that RT-3DE can provide more direct, accurate and abundant information.

CONCLUSIONS

RT-3DE is a simple and fast imaging technique, and the detailed 3D images obtained can be used to confirm the diagnosis of MVC. RT-3DE is considered to be an important preoperative test that provides more comprehensive information for selecting a subsequent procedure for treatment.

Three-dimensional echocardiography of congenital abnormalities of the left atrioventricular valve

Congenital abnormalities of the left atrioventricular (AV) valve are a significant diagnostic challenge. Traditionally, reliance has been placed on two-dimensional echocardiographic (2DE) imaging to guide recognition of the specific morphological features. Real-time 3DE can provide unique views of the left AV valve with the potential to improve understanding of valve morphology and function to facilitate surgical planning. This review illustrates the features of congenital abnormalities of the left AV valve assessed by 3DE. The similarities and differences in morphology between different lesions are described, both with respect to the valve itself and supporting chordal apparatus. The potential advantages as well as limitations of this technique in clinical practice are outlined.

Congenital malformations of the mitral valve

Congenital malformations of the mitral valve may be encountered in isolation or in association with other congenital heart defects. Each level of the mitral valve complex may be affected, according to the embryological development, explaining the fact that these lesions are sometimes associated with each other. As a perfect preoperative assessment is of importance, good knowledge of both normal and abnormal anatomy is required in order to guide the surgeon accurately. This review presents the different embryological, anatomical and echocardiographic aspects of the congenital mitral anomalies.

Successful mitral valve repair for severe mitral regurgitation caused by isolated cleft of the posterior leaflet

Cleft of the post mitral valve leaflet is extremely rare congenital cause of mitral regurgitation. Only six cases have being reported in literature. We report the case of a 34-year-old man with isolated cleft in the posterior mitral valve leaflet causing severe mitral regurgitation. The patient had been experiencing limitation of his exercise capacity becoming more easily tried. Therefore, he was referred for mitral valve surgery. The posterior mitral valve leaflet was successfully repaired using quadrangular resection technique. Intra-operative transesophageal echocardiography showed trivial mitral regurgitation after repair. Satisfactory clinical results were achieved at 2 years post-operatively.

Isolated cleft mitral valve with posterior and anterior clefts: a rare cause of congenital valve regurgitation

We report a case of isolated cleft mitral valve with two clefts in the posterior and one in the anterior leaflet. Our case adds to the few reports of posterior and multiple mitral valve clefts and to our knowledge is the first using real-time transoesophageal three-dimensional echocardiography (3DE) for assessment of isolated cleft mitral valve. (Echocardiography 2010;27:E50-E52).

Determination of the mitral papillary muscle positions by the septal-to-free wall arc ratio method

BACKGROUND

Determination of mitral papillary muscle positions is of increasing interest in wide spectrum of clinical cardiology fields. Particularly, relative positioning of the papillary muscles between the inter-ventricular septum and the left ventricular free wall is of interest. A reproducible method for determination of papillary muscle positions has not been established. In this study a new 'septal-to-free wall arc ratio' (SFAR) method for measuring papillary muscle positions is presented. The reproducibility of the SFAR method between echocardiographic (ECHO) and magnetic resonance (MRI) modalities and between observers is tested.

METHODS

Twenty subjects with structurally normal hearts in whom both MRI and ECHO were performed in 2007 were included in the study. Papillary muscle positions were determined using the SFAR method. Inter-modality (ECHO and MRI) and inter-observer reproducibility of the methods was assessed by calculating correlation coefficients and the mean difference from agreement.

RESULTS

The inter-modality correlation of the SFAR method was 0.80 (P < 0.0001) for both papillary muscles. The mean difference of measurements from agreement was 4% for the superior and 2% for the inferior papillary muscle. The inter-observer correlation was 0.93 (P < 0.0001) for superior and 0.90 (P = 0.0002) for inferior papillary muscle. The mean inter-observer difference from agreement was 2% for superior and 3% for inferior papillary muscle.

CONCLUSIONS

The SFAR method may be applied in wide range of both scientific and clinical medical fields as a reproducible method for determination of papillary muscle positions with the benefit of estimation of relative papillary muscle positions both from the septum and the free wall.

Isolated cleft posterior mitral valve leaflet: an uncommon cause of mitral regurgitation

A 53-year-old woman with a history of hypertension was referred for an echocardiogram by her primary care physician after an unspecified abnormal ECG. The echocardiogram showed normal left ventricular size and function; however, an isolated cleft posterior mitral valve leaflet was identified with concomitant bileaflet prolapse and mild mitral regurgitation. She was subsequently referred to a cardiologist for clinical evaluation. Cleft mitral valve leaflet (CMVL) is an uncommon congenital cause of mitral regurgitation. Clefts, defined as slit-like holes or defects, are hypothesized to be a result of incomplete expression of an endocardial cushion defect which most commonly involves the anterior mitral valve leaflet with a paediatric incidence of 1:1340. Clefts affecting only the posterior mitral valve leaflet are extremely rare with only four cases being reported in the medical literature. Important co-existing anomalies with either posterior and/or anterior CMVL include counterclockwise rotation of the papillary muscles, the presence of an accessory papillary muscle or mitral valve leaflet, atrial septal defects, and mitral valve prolapse. Regurgitation from CMVL can lead to important physiological and anatomical changes within the cardiac system. Regurgitation results from blood flow directly through the cleft itself or from malcoaptation from accessory chordae with or without papillary muscle distortion. Significant chronic mitral regurgitation elevates left atrial filling pressures and leads to chamber enlargement and eccentric left ventricular hypertrophy. Early detection through two-dimensional echocardiography can provide accurate anatomical images of the various mitral valve structures and identify associated congenital anomalies. Early surgical correction is preferred before mitral regurgitation causes unfavourable remodelling. Most mitral valve cleft defects can easily be repaired by suturing the edges of the cleft. If a cleft resection leads to limited residual valve tissue, the leaflet of the mitral valve can be reconstructed using an autologous pericardial patch pre-treated with buffered glutaraldehyde. Posterior CMVL is an uncommon but clinically important cause of mitral insufficiency. Early recognition of this rare clinical entity and possible co-existent anomalies can identify the patients who would benefit from surgical intervention before compensatory left ventricular remodelling and contractile dysfunction develop.