The relationship of mitral annular shape to the diagnosis of mitral valve prolapse.

Abstract

The geometric or anatomic diagnosis of mitral valve prolapse, as opposed to the pathologic diagnosis of myxomatous valve disease, is based on the relationship of the mitral leaflets to the surrounding anulus. Current echocardiographic criteria for this diagnosis include leaflet displacement above the annular hinge points in any two-dimensional view; implicit in this equivalent use of intersecting views is the assumption that the mitral anulus is a euclidean plane. Prolapse by these criteria is found in a surprisingly large proportion of the general population. In most of these individuals, however, prolapse is present in the apical four-chamber view and absent in roughly orthogonal long-axis views of the left ventricle. This frequently observed discrepancy between leaflet-annular relationships in intersecting views suggests an underlying geometric property of the mitral apparatus that would produce the appearance of prolapse in one view without actual leaflet distortion. To address this possibility, a model of the mitral valve and anulus was constructed. When the model anulus was given a nonplanar, saddle-shaped configuration, the clinical observations were reproduced: the leaflets appeared to lie above the low points of the anulus in one plane, and below its high points in a perpendicular plane. Therefore, the appearance of mitral valve prolapse can occur without actual leaflet displacement above the most superior points of the mitral anulus if the anulus is nonplanar. To determine whether this pattern is reflected in the human mitral anulus, two-dimensional echocardiographic views of the mitral apparatus were obtained by rotation about the cardiac apex in 20 patients without evident annular or rheumatic valvular disease. In all cases the mitral anulus, as reconstructed from these views, had a nonplanar systolic configuration, with high points located anteriorly and posteriorly. This is consistent with the findings of other groups in animals, and would favor the appearance of prolapse in the four-chamber view and its absence in long-axis views that are oriented anteroposteriorly. This model can therefore explain the frequently observed discrepancy between leaflet-annular relationships in roughly orthogonal views. It challenges the assumption that the mitral anulus is planar as well as the diagnosis of prolapse in many otherwise normal individuals based on that assumption. Circulation 75, No. 4, 756-767, 1987. PROLAPSE is defined as the displacement of a bodily part from its normal position or relationship. 1 The term mitral valve prolapse, therefore, implies that the mitral leaflets are displaced relative to some reference structure, generally taken to be the mitral anulus. Since

Flow structure in healthy and pathological left ventricles with natural and prosthetic mitral valves

“…According to Levine et al (1987), Salgo et al (2002), Votta et al (2008) and Mahmood et al (2010), the mitral annulus is flat during diastole and becomes saddle shaped only during systole. In particular, Salgo et al (2002) and Votta et al (2008) found that the annulus non-planarity mainly affects the mobility of the posterior leaflet and facilitates the valve closure.…”

Three-dimensional echocardiographic reconstruction of the mitral valve, with implications for the diagnosis of mitral valve prolapse.

“…Therefore, in principle, it is possible for the leaflets to lie above the annular insertion points in mediolateral imaging planes through the low points of the annulus (implying prolapse by current criteria),16"17 and to lie below the annular insertions in anteroposterior imaging planes through the high points (implying normality). 13 Clinical studies indicate that this may be the case. There is a higher prevalence of superior leallet displacement in a mediolateral plane (the apical four-chamber view) than in an anteroposterior plane (the parasternal long-axis view), 16"1720-22 particularly in otherwise normal individuals.5 Also, patients with leaflet displacement above the low points but not the high points of the annulus are similar to normal individuals, that is, free of the disease prolapse.…”

Prevalence of mitral valve prolapse in primary spontaneous pneumothorax

“…Images were recorded on a CD, including complete parasternal, apical and subscostal views, and colour Doppler assessment of the valvular regurgitation. We measured the displacement of the anterior and posterior mitral leaflets in the parasternal and apical long axis views, scanned by tilting the transducer to visualize all the three scallops of the posterior leaflets [8,9,12]. The thickness of the mitral leaflets during diastasis was measured from the leading to the trailing edge of the thickest area of the mid-portion of the leaflet, excluding focal areas of thickness and the chordae [13,14].…”

“…Echocardiographic MVP has been found in 50% of patients with PSP C o p y r ig h t G e n e r a l P r a c t ic e A ir w a y s G r o u p R e p r o d u c t io n p r o h ib it e d [7]. Studies describing the three-dimensional shape of the mitral annulus [8,9] have allowed the two-dimensional (2D-) echocardiographic characterization of the prolapse to be refined, thus minimizing false positive diagnoses [10,11]. We used current 2D-echocardiographic criteria to determine the prevalence of MVP in patients with PSP admitted to Adan teaching hospital in the Ahmadi Governorate in Kuwait.…”