**2.3.1 The triangle of coaptation**

The central feature of the normal mitral valve geometry is represented by the triangle of coaptation (Cerin, 2006, Tesler 2009). It is usually assessed by two dimensional echocardiography and is delimited by the coaptation point, which is normally sited within the left ventricular cavity, and two other points placed on the septal and lateral mitral annulus (FIG 2). The triangle presents a height, which may be considered the expression of the optimal balance between the elastic and collagen fibres of the mitral valve. In patients with degenerative mitral valve, the height of the triangle of coaptation, which is usually reduced, expresses the excess of elastic fibres.

Fig. 2. The concept of triangle of coaptation. The triangle of coaptation is formed by the two points sited on the mitral annulus (A, B) and the coaptation point. The coaptation point (C) is normally situated into the left ventricle. LV – left ventricle; LA – left atrium; Ao – aorta;

At the tip of this triangle, the echocardiographer has to measure the length of leaflet coaptation. The coaptation length and the coaptation height are cornerstone elements used in order to fully describe the valve geometry and to assess the result of the repair.

It may be assumed that from a volumetric and a three dimensional geometrical perspective, the triangle of coaptation corresponds roughly to an asymmetrical tent. In the course of perioperative echocardiographic study, the systematic analysis of the mitral valve apparatus is done, focusing on whether the triangle of coaptation is present or not. The main surgical purpose of repair is achieving a good leaflet coaptation of at least 6mm in length and whenever possible, rebuilding the triangle of coaptation. Due to the increased amount of myxomatous tissue and elastic fibres in the mitral apparatus, the degenerative mitral valve usually loses its normal geometry progressively, alters the triangle of coaptation, presents itself as, elongated chordae or as a truly prolapsing valve.

#### **2.4 The third step of standardization: Check the pattern of mitral valve lesions**

In degenerative mitral insufficiency, many types of mitral valve lesions were classically described in the literature: from the classical mitral prolapse or mitral flail, to the billowing or floppy mitral valve. For a true dialogue between the echocardiographer, anaesthesiologist, and surgeon, all the team has to rigorously know the meaning of the most frequent lesions found in these patients. Alongside the well-known classically patterns of lesions, our group identifies some other particular patterns of mitral valve injuries*,* such as: elongated chordae, marginal prolapse, overturned mitral valve, undulating mitral valve or the mitral valve's pseudo-cleft. The main echocardiographic pattern used for the characterization of the degenerated mitral valve is presented further on.

### **2.4.1 The pattern of 'elongated chordae'**

6 Echocardiography – In Specific Diseases

The normal mitral geometry is the concept that guides both the evaluation of the various valve lesions and the surgical strategy. This is a key concept, also very helpful in the

The central feature of the normal mitral valve geometry is represented by the triangle of coaptation (Cerin, 2006, Tesler 2009). It is usually assessed by two dimensional echocardiography and is delimited by the coaptation point, which is normally sited within the left ventricular cavity, and two other points placed on the septal and lateral mitral annulus (FIG 2). The triangle presents a height, which may be considered the expression of the optimal balance between the elastic and collagen fibres of the mitral valve. In patients with degenerative mitral valve, the height of the triangle of coaptation, which is usually

Fig. 2. The concept of triangle of coaptation. The triangle of coaptation is formed by the two points sited on the mitral annulus (A, B) and the coaptation point. The coaptation point (C) is normally situated into the left ventricle. LV – left ventricle; LA – left atrium; Ao – aorta;

At the tip of this triangle, the echocardiographer has to measure the length of leaflet coaptation. The coaptation length and the coaptation height are cornerstone elements used

It may be assumed that from a volumetric and a three dimensional geometrical perspective, the triangle of coaptation corresponds roughly to an asymmetrical tent. In the course of perioperative echocardiographic study, the systematic analysis of the mitral valve apparatus is done, focusing on whether the triangle of coaptation is present or not. The main surgical purpose of repair is achieving a good leaflet coaptation of at least 6mm in length and whenever possible, rebuilding the triangle of coaptation. Due to the increased amount of myxomatous tissue and elastic fibres in the mitral apparatus, the degenerative mitral valve usually loses its normal geometry progressively, alters the triangle of coaptation, presents

in order to fully describe the valve geometry and to assess the result of the repair.

itself as, elongated chordae or as a truly prolapsing valve.

**2.3 The second step of standardization: Evaluation of the mitral valve geometry** 

postoperative assessment of surgical result and for the echocardiographic follow up.

**2.3.1 The triangle of coaptation** 

reduced, expresses the excess of elastic fibres.

This pattern defines the situation when the coaptation point is found to be into the left ventricular cavity, immediately below the level of the mitral annulus*.* It is a borderline situation between a normal aspect of the mitral valve and the mitral prolapse. Usually is not associated with mitral regurgitation. For the surgical planning, it is important to recognise it and indicate it to the surgeon. Sometimes it may interest one or both leaflets (Figure 3), involving one or more scallops. The relatives of patients with truly mitral valve prolapse may sometimes present 'elongated chordae' during the echocardiographic exam, without the classical prolapse.

Fig. 3. The pattern of 'elongated chordae'. In the presence of 'elongated chordae', the coaptation point (C) is found into the left ventricular cavity, immediately below or at the level of the mitral annulus. Note the shape of the triangle of coaptation which is flattened. The coaptation height of the triangle has practically disappeared. LV – left ventricle; LA – left atrium; Ao – aorta.

### **2.4.2 The pattern of 'prolapsing valve'**

The pattern of 'prolapsing valve' was classically defined as the presence of the coaptation point into the left atrium, above the level of the mitral annulus (Figure 4). By definition, the

The Degenerative Mitral Valve Regurgitation:

**2.4.4 The pattern of 'marginal prolapse'** 

scallop prolapse of the posterior leaflet (Figure 6).

**2.4.5 The 'undulating mitral valve'** 

From Geometrical Echocardiographic Concepts to Successful Surgical Repair 9

The pattern of 'marginal prolapse' is a rare type of mitral lesion, defined as an isolated protrusion of the free border area of one scallop, usually up to the insertion of the second degree chordae. In case of marginal prolapse, the remaining part of the surface of the scallop may be normal, without the displacement of the coaptation point into the left atrium. It is never present as isolated lesion; the marginal prolapse, as a rule, is associated with a P2

Fig. 6. Marginal prolapse of the anterior leaflet, A2 scallop (arrow), shown in 2D (zoom) and 3 D Echo. Notice the "stair like aspect" of the anterior leaflet due to the regional prolapse located between the border of the valve and insertion of the second degree chordae (usually strut chordae). This is a hidden and tricky lesion, because its presence may transform the

The 'undulating mitral valve' is usually a redundant mitral valve, with excessive tissue, presenting with diastolic fluttering of the free border of both leaflets. In most cases, the prolapsing score is high, approximately 8/8 and as a rule, for the surgeon, it means a complex mitral repair. It is important to underline that the border or a normal mitral valve

Fig. 7. Undulating mitral valve. TEE deep trans-gastric short axis view. Notice the undulating

aspect of the free borders of the leaflets (much more evident on moving pictures).

simple mitral plasty of one leaflet, in a complex mitral repair of both leaflets.

opens in a linear manner, without diastolic fluttering of the edge.

lesion has to be present in PSLAx view, otherwise, due to the shaded shape of the mitral valve, a false diagnose of mitral prolapse may be possible.

Fig. 4. Prolapsing mitral valve, with both leaflet involvement, shown in the 2D transthoracic parasternal long axis view. Notice the coaptation point (C) sited into the left atrium, behind the virtual line of the mitral annulus.
