Clinical significance of the echocardiographic degree of mitral valve prolapse

Does the association between mitral valve prolapse and panic disorder really exist?

OBJECTIVE

Although the possible relationship between panic disorder and mitral valve prolapse (MVP) attracted considerable research interest in the 1980s and 1990s, the reported prevalence of MVP in these patients has been inconsistent and widely variable. Clinical and epidemiologic studies have produced controversial data on possible association or definite causal relationship between these 2 entities. The primary objective of the present review was to summarize the current state of knowledge on the association between panic disorder and MVP, including the influence of diagnostic criteria for MVP on the controversial results.

DATA SOURCES

We searched MEDLINE, LILACS, and EMBASE databases using the keywords panic and mitral. Inclusion criteria were articles concerning the reciprocal association of MVP and panic disorder, published from the earliest dates available through December 2006.

STUDY SELECTION

All relevant articles published in English, Spanish, or Portuguese and reporting original data related to the association of MVP and panic disorder were included. Forty articles fulfilling the criteria for inclusion in this review were identified.

DATA SYNTHESIS

Even though the reported prevalence of MVP in panic disorder varied from 0% to 57%, a significant association between the 2 disorders was documented in 17 of the 40 studies. Such inconsistent results were due to sampling biases in case or control groups, widely different diagnostic criteria for MVP, and lack of reliability of MVP diagnosis. None of the reviewed studies used the current state-of-the-art diagnostic criteria for MVP to evaluate the volunteers. Apparently, the more elaborate the study methodology, the lower the chance to observe a significant relationship between these 2 conditions.

CONCLUSIONS

Published results are insufficient to definitely establish or to exclude an association between MVP and panic disorder. If any relationship does actually exist, it could be said to be infrequent and mainly occur in subjects with minor variants of MVP. To clarify this intriguing issue, future studies should mainly focus on the observed methodological biases and particularly should use the current criteria for MVP as the standard for evaluation.

The Mitral Regurgitation Index: an echocardiographic guide to severity

OBJECTIVES

The purpose of this study was to develop a semiquantitative index of mitral regurgitation severity suitable for use in daily clinical practice and research.

BACKGROUND

There is no simple method for quantification of mitral regurgitation (MR). The MR Index is a semiquantitative guide to MR severity. The MR Index is a composite of six echocardiographic variables: color Doppler regurgitant jet penetration and proximal isovelocity surface area, continuous wave Doppler characteristics of the regurgitant jet and tricuspid regurgitant jet-derived pulmonary artery pressure, pulse wave Doppler pulmonary venous flow pattern and two-dimensional echocardiographic estimation of left atrial size.

METHODS

Consecutive patients (n = 103) with varying grades of MR, seen in the Adult Echocardiography Laboratory at UCSF, were analyzed retrospectively. All patients were evaluated for the six variables, each variable being scored on a four point scale from 0 to 3. The reference standards for MR were qualitative echocardiographic evaluation by an expert and quantitation of regurgitant fraction using two-dimensional and Doppler echocardiography. A subgroup of patients with low ejection fraction (EF < 50%) were also analyzed.

RESULTS

The MR Index increased in proportion to MR severity with a significant difference among the three grades in both normal and low EF groups (F = 130 and F = 42, respectively, p < 0.0001). The MR Index correlated with regurgitant fraction (r = 0.76, p < 0.0001). An MR Index > or =2.2 identified 26/29 patients with severe MR (sensitivity = 90%, specificity = 88%, PPV = 79%). No patient with severe MR had an MR Index <1.8 and no patient with mild MR had an MR Index >1.7.

CONCLUSIONS

The MR Index is a simple semiquantitative estimate of MR severity, which seems to be useful in evaluating MR in patients with a low EF.

Relationship between severity of mitral regurgitation and prognosis of mitral valve prolapse: echocardiographic follow-up study

We investigated the relation between the severity of mitral regurgitation and the development of complications and cardiac events by using two-dimensional and color Doppler echocardiography in 229 consecutive patients with mitral valve prolapse. The frequency of moderate and severe mitral regurgitation was significantly higher in patients with a prolapsed posterior leaflet (61%) than in patients with a prolapsed anterior leaflet (25%), and the older the patient, the greater the severity of mitral regurgitation. The occurrence of complications, such as atrial fibrillation, congestive heart failure, and chordal rupture, was significantly greater in prolapsed posterior leaflet cases than in prolapsed anterior leaflet cases, and the occurrence was closely associated with the degree of severity of mitral regurgitation. Multiple logistic regression analysis showed that the severity of mitral regurgitation is a strong prognostic indicator for developing complications. Furthermore in a subgroup of 49 patients tracked for a mean of 4.8 years, the new development of complications was significantly higher in patients who showed a progression in the severity of mitral regurgitation (52%) that in patients without progression in severity (8%). The initial severity of mitral regurgitation was related to the occurrence of cardiac events (mitral valve replacement, infective endocarditis, cerebral embolism and death). The data indicated that the progression of mitral regurgitation is closely associated with the development of complications and cardiac events and suggest that the severity of mitral regurgitation is an important prognostic indicator for the development of complications and cardiac events in patients with mitral valve prolapse.

Spectrum of structural abnormalities in floppy mitral valve echocardiographic evaluation

Posterior displacement of the mitral valve with billowing into the left atrium has been the major echocardiographic criterion used for the diagnosis of mitral valve prolapse (MVP). However, the current criteria are limited by the influence of hemodynamic factors on the degree of prolapse, whereas complications such as mitral regurgitation, endocarditis, and need for surgery have been associated with redundancy or thickening of the leaflets. Sixty-eight normal subjects (mean age, 40 years; range, 18 to 76 years) were compared with 58 patients with MVP (mean age, 37 years, range, 18 to 83 years). Leaflet displacement across the annular plane in the parasternal long-axis view was mandatory for the diagnosis of MVP. Transthoracic echocardiographic measurements of anterior and posterior leaflet thickness, leaflet length, and chordal length were made from the parasternal long-axis view and the mitral annular diameter, from the apical four-chamber and two-chamber views. The MVP group had greater anterior thickness (4.1 +/- 0.4 mm vs 5.3 +/- 0.7 mm; p = 0.0001), posterior thickness (3.2 +/- 0.4 mm vs 4.7 +/- 0.9 mm; p = 0.0001), anterior length (22.8 +/- 2.0 mm vs 25.7 +/- 1.7 mm; p = 0.0001), posterior length (12.8 +/- 1.0 mm vs 15.7 +/- 2.5 mm; p = 0.0001), chordal length (25.6 +/- 2.7 mm vs 28.0 +/- 2.5 mm; p = 0.0001), and annular diameter (29.1 +/- 1.5 mm vs 31.3 +/- 2.6 mm; p = 0.0001). Of the MVP group, >80% had at least one abnormality identified and >50% had at least two abnormalities. In addition, patients with MVP with significant regurgitation had greater anterior thickness (5.2 +/- 0.7 mm vs 5.8 +/- 0.8 mm; p = 0.015), posterior thickness (4.5 +/- 0.9 mm vs 5.3 +/- 0.7 mm; p = 0.024), posterior length (15.1 +/- 1.6 mm vs 17.9 +/- 4.2 mm; p = 0.004), and annular diameter (36.0 +/- 2.0 mm vs 33.3 +/- 2.1 mm; p = 0.0001). The majority of patients with floppy mitral valves resulting in MVP have structural abnormalities that may be defined by echocardiography. A spectrum of floppy valve structure is demonstrated by echocardiography, with mitral regurgitation occurring more frequently in patients with multiple and more severe anatomic abnormalities. In addition to the presence of prolapse and regurgitation, the assessment of leaflet thickness, leaflet length, annular diameter, and chordal length is fundamental to the definition and stratification of patients with MVP associated with the floppy mitral valve.

Exercise-induced mitral regurgitation is a predictor of morbid events in subjects with mitral valve prolapse

OBJECTIVES

This study attempted to determine whether a subset of patients with mitral valve prolapse and no mitral regurgitation at rest will develop mitral regurgitation during exercise and have a higher than anticipated risk of morbid cardiovascular events.

BACKGROUND

Mitral regurgitation in patients with mitral valve prolapse identifies a subset of patients at higher risk for morbid events. However, mitral regurgitation in patients with mitral valve prolapse may be intermittent and could go unrecognized. A provocative test to unmask mitral regurgitation in these patients would be useful.

METHODS

Ninety-four adult patients with mitral valve prolapse and no mitral regurgitation at rest were studied during supine bicycle ergometry using color flow Doppler echocardiography in the apical four-chamber and long-axis views. Patients were prospectively followed up for morbid events.

RESULTS

Thirty (32%) of 94 patients had exercise-induced mitral regurgitation. Prospective follow-up (mean 38 months) showed more morbid events in the group with than without mitral regurgitation and included, respectively, syncope (43% vs. 5%, p < 0.0001), congestive heart failure (17% vs. 0%, p < 0.005) and progressive mitral regurgitation requiring mitral valve replacement surgery (10% vs. 0%, p < 0.05). Cerebral embolic events, endocarditis or sudden death were rare and not different between groups.

CONCLUSIONS

In patients with mitral valve prolapse without mitral regurgitation at rest, exercise provokes mitral regurgitation in 32% of patients and predicts a higher risk for morbid events.

Echocardiography in the management of mitral valve prolapse

Echocardiography plays a major role in the management of patients with mitral valve prolapse (MVP). The technique has greatly enhanced our understanding of the pathophysiology, epidemiology and natural history. There are major and minor echocardiographic diagnostic criteria for prolapse. Major criteria involve the mitral leaflets and include late systolic posterior displacement on M-mode, bulging into the left atrium on 2D long-axis (LAX) view, and thickening and redundancy of the leaflets. Minor criteria include holosystolic posterior prolapse on M-mode, bowing of the mitral leaflets into the left atrium (LA) in the apical 2D views, and late systolic mitral regurgitation on the Doppler echogram. Any of the major criteria should be sufficient to make the diagnosis. One or two minor criteria without a major sign would be questionable. The degree of thickening and redundancy and the presence and quantitation of mitral regurgitation influence prognosis. Echocardiography is also helpful in identifying complications such as endocarditis and ruptured chordae. An echocardiogram may not be necessary for the diagnosis, but it is helpful for prognosis and as a baseline for possible future changes. The frequency of follow-up echocardiograms should be determined by clinical findings. When mitral regurgitation is present, then one should follow LA and left ventricular size and function. Transoesophageal echocardiography may be desirable for better definition of vegetations or flail leaflets and is frequently used to monitor surgical repair.

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.

Linkage analysis of five fibrillar collagen loci in a large French Marfan syndrome family

Marfan syndrome consists of a group of dominantly inherited disorders of connective tissue with wide clinical variability. Using the candidate gene approach, we have attempted to map the gene defect in a large French Marfan syndrome family with no ocular manifestations. We performed linkage studies with polymorphic probes for five structural procollagen genes. The data obtained exclude linkage of Marfan syndrome to the two major fibrillar collagen (COL1A1, COL1A2, and COL2A1) genes. These results confirm previously published data obtained from smaller pedigrees. A small positive lod score (Z = 0.99, theta = 0.00) was obtained for the COL3A1-COL5A2 gene cluster located on chromosome 2.

Follow-up in mitral valve prolapse by phonocardiography, M-mode and two-dimensional echocardiography and Doppler echocardiography

To assess the serial phonocardiographic and echocardiographic change in patients with mitral valve prolapse (MVP), phonocardiograms and echocardiograms were reviewed retrospectively in 116 patients (48 men and 68 women, mean age 27 years) who had been determined to have MVP and were reexamined 4.3 years (range 1 to 14) later by phonocardiography and echocardiography between 1971 and 1988. Follow-up phonocardiograms showed periods when 5 of 18 patients with silent MVP developed mid- or late systolic clicks. Of 57 patients with mid- or late systolic clicks, 15 had silent MVP, 6 developed a late systolic murmur with or without systolic clicks and 1 developed a pansystolic murmur. Two of 9 patients with an isolated late systolic murmur developed a pansystolic murmur. M-mode echocardiograms showed that left atrial and left ventricular dimensions at end-diastole and end-systole increased in patients with systolic murmur (33 +/- 10 vs 35 +/- 11, 46 +/- 6 vs 50 +/- 7 and 29 +/- 4 vs 31 +/- 5 mm, respectively, all p less than 0.001) and no statistically significant changes in any of these dimensions were found in patients without a systolic murmur. The degree of MVP evaluated by the anteroposterior mitral leaflet angle on the 2-dimensional echocardiogram was more severe in patients with a systolic murmur than in patients without systolic murmur (157 +/- 12 vs 131 +/- 16 degrees, p less than 0.001). The degree of prolapse did not change during the follow-up periods. The number of patients with mitral regurgitation detected by pulsed Doppler echocardiography increased from 21 of 72 (29%) to 31 of 72 (43%).(ABSTRACT TRUNCATED AT 250 WORDS)