Mitral Leaflet Thickness Research Articles

Transesophageal echocardiographic assessment of the contribution of intrinsic tissue thickness to the appearance of a thick mitral valve in patients with mitral valve prolapse

This prospective, blinded transesophageal echocardiographic study was performed to determine the relative contributions of leaflet redundancy and overlap versus intrinsic tissue thickening as mechanisms for the apparent increase in diastolic thickness of the mitral valve. Increased diastolic thickness of the mitral valve has been identified as an echocardiographic feature that predicts subsequent adverse sequelae in patients with mitral valve prolapse (MVP). Eleven patients with clinical and transthoracic echocardiographic evidence of MVP and 11 age-matched control subjects underwent protocol transesophageal echocardiography to image the mitral valve in two orthogonal planes and to measure its thickness in systole and diastole. Maximal diastolic width of the slack, unloaded anterior leaflet was significantly greater in patients with MVP than in control subjects (mean +/- SD: 0.64 +/- 0.20 cm vs. 0.30 +/- 0.04 cm, p < 0.001). Similarly, diastolic posterior leaflet width was greater in patients with MVP (0.67 +/- 0.39 cm vs. 0.31 +/- 0.06 cm, p < 0.01). In contrast, minimal systolic width of the distended pressure-loaded mitral valve was not significantly different between patients with MVP and control subjects for either the anterior (0.22 +/- 0.05 cm vs. 0.20 +/- 0.04 cm, p = NS) or the posterior (0.25 +/- 0.07 cm vs. 0.24 +/- 0.05 cm, p = NS) leaflets. The percent change in leaflet width from diastole to systole (% delta W), an index of the contribution of dynamic factors (e.g., leaflet redundancy and overlap) to the apparent increase in diastolic leaflet thickness, was significantly greater in patients with MVP than in control subjects for both the anterior (% delta W 62 +/- 13% vs. 34 +/- 16%, p < 0.001) and the posterior (% delta W 54 +/- 19% vs. 22 +/- 21%, p < 0.005) leaflets. The apparent increase in diastolic mitral leaflet thickness in patients with MVP versus control subjects is largely attributable to dynamic factors such as leaflet redundancy, overlap and deformation. During diastole, when the mitral leaflets are slack and unstressed, the leaflets appear markedly thickened in patients with MVP. In contrast, during systole, when developed intraventricular pressure distends the leaflets, causing them to stretch and balloon into the left atrium, the intrinsic tissue thickness is much less than that measured in diastole. These findings have important implications for the morphologic criteria used to diagnose MVP and the potential pathophysiologic mechanisms for adverse sequelae in this syndrome.

747-5 Transesophageal Echocardiographic Quantitation of Mitral Leaflet Thickness in Patients with Mitral Valve Prolapse

Mitral leaflets which appear abnormally thick by transthoracic echo predict an adverse prognosis in pts with mitral valve prolapse (MVP). While it is known from pathologic studies that the valve tissue in such pts is both redundant and abnormally thick, the echocardiographic appearance of increased thickness may result from a combination of overlap of redundant tissue and intrinsic increases in leaflet thickness. Transesophageal echo (TEE) affords the opportunity to more precisely characterize the morphology of the mitral leaflets in these patients. Accordingly, twenty-two pts [11 with MVP (defined as superior displacement of the mitral leaflets above the mitral annulus on the parasternal long axis view of the transthoracic echo and increased diastolic width of the anterior mitral leaflet) and 11 controls (CTRL)] prospectively underwent detailed TEE examination to quantify mitral leaflet thickness. Since systolic tensing of the closed mitral leaflets minimizes tissue overlap, systolic leaflet width was used to measure intrinsic tissue thickness. In contrast, the width of the relatively slack mitral leaflets in diastole represents a combination of both leaflet overlap and intrinsic tissue thickness. Blinded TEE measurements of leaflet width demonstrated greater diastolic width of both anterior (0.64 ± 0.20 v. 0.30 ± 0.04 em, p &lt; 0.001) and posterior (0.67 ± 0.39 v. 0.31 ± 0.06 em, p &lt; 0.01) leaflets in MVP compared to CTRL. In contrast systolic width of the anterior (0,22 ± 0.05 v, 0.20 ± 0.04 em, NS) and posterior (0.25 ± 0.07 v. 0.24 ± 0.05 em, NS) leaflets were similar in MVP and CTRL. Fractional change in leaflet width from diastole to systole (%ΔW = [(diastolic width) - (systolic Width)] × 100/[diastolic width]) was measured as an index of the change in leaflet overlap between diastole and systole, %LΔW was significantly greater for both anterior (62 ± 13 v. 34 ± 16%, p &lt; 0.001) and posterior (54 ± 19 v. 22 ± 21%, p &lt; 0.005) leaflets in MVP compared to CTRL. In MVP the echocardiographic appearance of increased diastolic mitral leaflet thickness is largely due to tissue overlap of the redundant leaflets, while they are relatively slack. By contrast under systolic tensioning, which minimizes tissue overlap, the leaflet thickness appears similar in MVP pts and CTRL.

942-42 Is Mitral Valve Prolapse with Significant Mitral Regurgitation a Different Condition from Uncomplicated Mitral Prolapse? Results of Family Studies

Mild instances of mitral valve prolapse (MVP) have been suggested to represent variants of normal, whereas individuals with complicated forms of MVP have a distinct medical condition. This hypothesis would predict different phenotypic features and patterns of inheritance in relatives of index cases with complicated or uncomplicated MVP. Accordingly, we performed clinical and echocardiographic assessment of 16 MVP patients with and 76 without moderate to severe mitral regurgitation (MR+and MR– probands) and 60 and 256, respectively, first-degree relatives (MR+ and MR– relatives). MR+ probands were older (p = 0.01), more likely to be male (p = 0.002), were more overweight (p = 0.004) and had higher systolic blood pressures (p = 0.05) and larger aortic roots (p = 0.034) after the effects of age and body size were taken into account. MR+ and MR– relatives had similar prevalences (27 and 32%) and age distribution of MVP, but affected MR+ relatives were younger (expected because more children and fewer parents of MR+ probands could be evaluated). and more likely to be male. MR+ and MR- relatives were virtually identical in regard to body habitus, blood pressure, the prevalence of auscultatory findings, thoracic bony abnormalities and palpitations and all echo measurements including anterior mitral leaflet thickness. Four instances of significant MR and two MVP-related complications (infective endocarditis and transient ischemic attack) occurred in the 82 relatives of MR– probands as opposed to none among relatives of MR+ probands. In 20 families, one proband or relative with MVP had severe MR and at least one other with MVP (presumably due to the same gene) was free of MR or complications. Thus, MVP with severe MR does not represent a heritable phenotype and commonly coexists with mild forms of MVP in the same family, making their classification as separate conditions illogical and potentially misleading.

Arrhythmias in mitral valve prolapse: Relation to anterior mitral leaflet thickening, clinical variables, and color Doppler echocardiographic parameters

Atrial and ventricular arrhythmias have been reported with variable incidence in symptomatic patients with mitral valve prolapse (MVP). The role of clinical and echocardiographic parameters as predictors for arrhythmias still needs to be clarified. One hundred nineteen consecutive patients (56 women and 63 men, mean age 40 ± 17 years) with echocardiographically diagnosed MVP were examined. A complete echocardiographic study (M-mode, two-dimensional, and Doppler) and 24-hour electrocardiographic monitoring were performed in all patients. Complex atrial arrhythmias (CAAs) included atrial couplets, atrial tachycardia, and paroxysmal or sustained atrial flutter or fibrillation. Complex ventricular arrhythmias (CVAs) included multiform ventricular premature contractions (VPCs), VPC couplets, and runs of three or more sequential VPCs (salvos of ventricular tachycardia). The relation between complex arrhythmias and clinical parameters (age and gender) and echocardiographic parameters (left atrial and left ventricular dimensions, anterior mitral leaflet thickness [AMLT], and presence and severity of mitral regurgitation) was evaluated by multiple logistic regression analysis. CAA were present in 14% of patients and CVA in 30%. According to multiple logistic modeling, CAA correlated separately in the univariate analysis with age, presence of MR, and left ventricular and left atrial diameters; age was the only independent predictor ( p < 0.001). CVA, in the univariate analysis, correlated with age, female gender, left ventricular end-diastolic diameter, and AMLT; only female gender and AMLT were independent predictors in the multivariate analysis ( p < 0.01). The incidence of mitral regurgitation (59%) was higher than expected in a general population of MVP patients. In conclusion, in this population with MVP, age was independently correlated to CAA, whereas female gender and AMLT were independently related to CVA.

Prediction of change in mitral valve area after mitral balloon commissurotomy using cine computed tomography.

Mitral balloon commissurotomy (MBC) can successfully increase the mitral valve area (MVA) in mitral stenosis, but the outcome is variable. In multicenter studies, qualitative echocardiographic scores obtained before MBC are only weakly predictive of the increase in MVA after MBC. To evaluate whether the change in MVA after MBC can be predicted by evaluating mitral valve morphology using cine computed tomography (CT), we studied 12 women with mitral stenosis and 11 female control subjects. In the patients with mitral stenosis, MVA increased from 1.13 +/- 0.24 to 1.93 +/- 0.56 cm2 (P < .0001) after MBC. A standard echocardiographic score assessment of mitral valve morphology before MBC was not associated with the change in MVA after MBC in these patients (P > .20). However, the total mitral valve morphology score evaluated by cine computed tomography was strongly associated with the change in MVA after MBC (r = -.87; P < .0005). In addition, the individual morphologic characteristics of mitral valve mobility (P < .0025), leaflet thickness (P < .05), and subvalvular disease (P < .05) were significant predictors of the change in MVA after MBC. Cine computed tomography may be useful for predicting immediate increases in MVA in patients after MBC and may be helpful for preoperative assessment of these patients.

In vivo mitral valve morphology and motion in mitral valve prolapse

Mitral leaflet morphology in mitral valve prolapse (MVP) has been suggested to be prognostically important, but in vivo valvular morphology is incompletely described in patients with MVP or in normal subjects. Accordingly, the length of both mitral leaflets and their zone of apposition, the thickness of their rough and clear zones, diastolic and systolic mitral annular diameters, and indexes of abnormal leaflet motion were measured in the parasternal long-axis echocardiographic view in 100 patients with MVP and 100 age- and sex-matched normal subjects. In both groups posterior leaflet thickness was related to age, as were anterior leaflet thickness and posterior leaflet length in patients with MVP. Compared with normal subjects, MVP patients without mitral regurgitation had thickened leaflets, elongated anterior leaflets, and large annular diameters (p < 0.0001). Patients with severe regurgitation had thicker leaflets, longer posterior leaflet and annular dimensions, and more abnormal leaflet motion than MVP patients without regurgitation. Leaflet thicknesses of different zones were supranormal in 60% to 67% and in 49% to 59% of MVP patients with and without severe regurgitation, respectively. MVP patients with regurgitation also had higher prevalences of abnormal mitral annular diameter than those without regurgitation (67% vs 29%) and > 3 mm posterior leaflet billowing into the left atrium (60% vs 34%). Thus, mitral valve size and leaflet thickness are increased in MVP patients without as well as with clinically important mitral regurgitation. The usefulness of leaflet thickening as a marker of severe MVP is limited by its high prevalence in patients with clinically mild MVP.

Evaluation of mitral stenosis by cine magnetic resonance imaging

To evaluate the ability of cine magnetic resonance imaging (cine MRI) in the assessment of mitral stenosis (MS), we studied 20 patients (14 women and 6 men, mean age 60.6 ± 8.5 years) with rheumatic mitral valve stenosis by using an 0.5 T magnet. Cine MRI showed several signs of MS. Mitral leaflet thickening, reduced diastolic opening, and abnormal valve motion toward the left ventricular outflow tract were all common features. MS was also characterized by an abnormal diastolic transmitral signal from blood. Both left atrial and left ventricular dimensions were similar to those obtained at two-dimensional echocardiography (2-DE) ( r = 0.89andr = 0.86, respectively; p < 0.001). A significant relationship was also found between the maximum mitral leaflet separation measured by cine MRI in diastole and the mitral valve area as calculated using the pressure half-time method and continuous wave Doppler ( r = 0.81; p < 0.001). These data indicate the improved ability of MRI to detect and assess MS and also suggest that this technique may contribute to the noninvasive assessment of MS.

Cardiac involvement in patients with primary antiphospholipid syndrome

To evaluate cardiac involvement in primary antiphospholipid syndrome, two-dimensional and Doppler echocardiographic studies were performed in 34 consecutive patients with this syndrome. All patients had an increased level of serum anticardiolipin antibodies with no evidence of malignancy or systemic lupus erythematosus. The clinical manifestations of primary antiphospholipid syndrome were arterial thrombosis in 14 patients, venous thrombosis in 6 and recurrent fetal loss in 14. Valvular lesions were observed on two-dimensional echocardiography in 11 patients (32%) (9 women and 2 men), aged 24 to 57 years (mean ± 1 SD 36 ± 10).Abnormal echocardiographic findings were observed in 9 (64%) of 14 patients with arterial thrombosis versus 1 (17%) of 6 patients with venous thrombosis and 1 (7%) of 14 patients with recurrent fetal loss. The most common echocardiographic abnormality was mitral leaflet thickening, found in five patients; this was associated with mitral regurgitation in three and with combined mild mitral stenosis and regurgitation in one patient. Localized subvalvular mitral thickening was observed in one patient and calcification of the anulus in another. Aortic valve thickening was observed in two patients, one of whom also had a moderate degree of aortic regurgitation. Vegetation-like lesions on the mitral or aortic valve were found in two patients.It is concluded that valvular lesions are commonly found in primary antiphospholipid syndrome, particularly when the syndrome is manifested by peripheral arterial thrombosis. The location and appearance of valvular lesions in this syndrome are heterogeneous. Most patients have no clinically significant valvular disease. Two-dimensional and Doppler echocardiographic studies are often informative in these patients.

Relation of echocardiographic morphology of the mitral apparatus to mitral regurgitation in mitral valve prolapse: Assessment by Doppler color flow imaging

Few data exist regarding the relationship of valvular anatomy and coaptation to the presence of mitral regurgitation (MR) in patients with mitral valve prolapse (MVP). Therefore this study was undertaken to assess the ability of two-dimensional echocardiographic features of mitral valve morphology to predict the presence, direction, and magnitude of MR as assessed by color Doppler flow imaging. MR was present in 21 of 46 patients with MVP on two-dimensional echocardiography. Echocardiograms were specifically evaluated for leaflet apposition, leaflet morphology, and mitral anulus diameter. Color flow images were analyzed for presence of MR, direction of the regurgitant jet, and area encompassing the largest jet visible in any view. Abnormal mitral leaflet coaptation on two-dimensional echocardiography was strongly associated with the presence of MR (p = 0.003), being present in 15 of 21 patients with as compared with 5 of 25 patients without MR. Similarly, mitral leaflet thickness and MR were closely associated (p = 0.0035), with the latter being present in 9 of 30 patients with normal and 12 of 16 patients with excessive leaflet thickness. MR jet direction tended to be anterior to central with posterior leaflet prolapse and posterior or central with anterior leaflet prolapse (p = 0.02). Maximal jet area of MR tended to be larger in patients with compared with those without mitral annular dilatation (5.4 +/- 2.3 versus 2.1 +/- 1.9 cm2, p = 0.001), and in those with abnormal rather than normal leaflet thickness (4.5 +/- 2.7 versus 2.0 +/- 1.6 cm2, p = 0.009). Thus the presence, direction, and size of MR jets in MVP are related to structural abnormality of the mitral apparatus on echocardiography.

Identification of the increased frequency of cardiovascular abnormalities associated with mitral valve prolapse by two-dimensional echocardiography

Two-dimensional echocardiography (2-D echo) was performed in 86 consecutive patients with mitral valve prolapse (MVP) and in 25 normal subjects. In normal subjects, mitral leaflet thickness was 3.5 +/- 0.8 mm (mean +/- standard deviation) and the mitral leaflet thickness to aortic wall thickness ratio was 1.0 +/- 0.2. Patients with MVP were separated into 2 groups: those with normal mitral thickness (less than or equal to mean + 2 SD observed in normal subjects, i.e., less than or equal to 5.1 mm) and normal mitral thickness to aortic wall thickness ratio (less than or equal to mean + 2 SD observed in normal subjects, i.e., less than or equal to 1.4) (group I) and others in whom these values were increased (group II). In group I, mitral thickness was 3.6 +/- 0.6 mm and mitral thickness to aortic wall thickness ratio was 1.1 +/- 0.1, and in group II, mitral thickness was 8.8 +/- 1.2 mm and mitral thickness to aortic wall thickness ratio was 2.2 +/- 0.5. The only significant cardiovascular abnormalities in group I were mitral regurgitation in 2 patients and tricuspid valve prolapse in 1 patient. In group II, 7 patients had clinically significant mitral regurgitation, 8 had aortic root abnormalities, 4 had tricuspid valve prolapse and 6 had Marfan's syndrome. Cardiovascular abnormalities were present in 60% (18 of 30) of patients in group II and in 6% (3 of 56) of patients in group I (p less than 0.001). Two-dimensional echo enabled the identification of a subset of patients with MVP who had thickened mitral leaflets. These patients had an increased incidence of cardiovascular abnormalities.

Two-dimensional echocardiographic assessment of the idiopathic hypereosinophilic syndrome. Anatomic basis of mitral regurgitation and peripheral embolization.

Important cardiac manifestations in the idiopathic hypereosinophilic syndrome include mitral regurgitation and peripheral embolization. To determine the anatomic basis of these abnormalities, real-time, wide-angle, two-dimensional echocardiography (2-D echo) was performed in 21 patients with the hypereosinophilic syndrome. Nine patients (43%) had clinical evidence of mitral regurgitation, and each had localized thickening of the posterobasal left ventricular wall behind the posterior mitral leaflet and absent (seven patients) or diminished (two patients) motion of the posterior leaflet. Anatomic observations at operation or necropsy in four patients with mitral regurgitation demonstrated that the echocardiographic abnormalities resulted from posterior mitral leaflet thickening and adherence of the leaflet to the underlying mural endocardium of the posterobasal wall. On 2-D echo, each of the six patients with peripheral emboli had either apical left ventricular echo-dense targets consistent with thrombus or thickening of the posterobasal wall of the left ventricle, and these findings were validated at autopsy or operation in three patients. Hence, in patients with the hypereosinophilic syndrome, 2-D echo is useful in identifying the probable etiology of two important cardiac manifestations. Thickening of the posterobasal wall is usually associated with impairment of posterior mitral leaflet function, resulting in mitral regurgitation. Because the hypereosinophilic syndrome is associated with peripheral embolization, thrombus formation and subsequent endocardial scarring, the noninvasive identification of intracavitary ventricular thrombi may be important.

The Echocardiogram in Scleroderma Endocarditis of the Mitral Valve

Echocardiography was performed in a woman with long-standing scleroderma with the CRST syndrome in whom the murmur of mitral regurgitation had been present for one year. The echocardiogram showed an irregular shaggy thickening of the anterior mitral valve leaflet. At autopsy three months later, myocardial fibrosis, small coronary artery sclerosis, and nodular thickening of the mitral valve were found. To our knowledge, anterior mitral leaflet thickening in scleroderma has not been reported previously. In this patient, it was associated with a poor prognosis.