Risk of infective endocarditis in mitral valve prolapse with and without precordial systolic murmurs

Mitral Valve Prolapse and Its Motley Crew-Syndromic Prevalence, Pathophysiology, and Progression of a Common Heart Condition

Mitral valve prolapse (MVP) is a commonly occurring heart condition defined by enlargement and superior displacement of the mitral valve leaflet(s) during systole. Although commonly seen as a standalone disorder, MVP has also been described in case reports and small studies of patients with various genetic syndromes. In this review, we analyzed the prevalence of MVP within syndromes where an association to MVP has previously been reported. We further discussed the shared biological pathways that cause MVP in these syndromes, as well as how MVP in turn causes a diverse array of cardiac and noncardiac complications. We found 105 studies that identified patients with mitral valve anomalies within 18 different genetic, developmental, and connective tissue diseases. We show that some disorders previously believed to have an increased prevalence of MVP, including osteogenesis imperfecta, fragile X syndrome, Down syndrome, and Pseudoxanthoma elasticum, have few to no studies that use up-to-date diagnostic criteria for the disease and therefore may be overestimating the prevalence of MVP within the syndrome. Additionally, we highlight that in contrast to early studies describing MVP as a benign entity, the clinical course experienced by patients can be heterogeneous and may cause significant cardiovascular morbidity and mortality. Currently only surgical correction of MVP is curative, but it is reserved for severe cases in which irreversible complications of MVP may already be established; therefore, a review of clinical guidelines to allow for earlier surgical intervention may be warranted to lower cardiovascular risk in patients with MVP.

Mitral Prolapse: An Old Mysterious Entity - The Incremental Role of Multimodality Imaging in Sports Eligibility

Mitral valve prolapse is generally a benign condition characterized by fibromyxomatous changes of the mitral leaflet with displacement into the left atrium and late-systolic regurgitation. Although it is an old clinical entity, it still arouses perplexity in diagnosis and clinical management. Complications, such as mitral regurgitation (MR), atrial fibrillation, congestive heart failure, endocarditis, ventricular arrhythmias, and sudden cardiac death (SCD), have been reported. A large proportion of the overall causes of SCD in young competitive athletes is explained by mitral valve prolapse. Recent studies have shown the fibrosis of the papillary muscles and inferobasal left ventricular wall in mitral valve prolapse, suggesting a possible origin of ventricular fatal arrhythmias. Athletes with mitral valve prolapse and MR should undergo annual evaluations including physical examination, echocardiogram, and exercise stress testing to evaluate the cardiovascular risks of competitive sports and obtain the eligibility. In this setting, multimodality imaging techniques – echocardiography, cardiac magnetic resonance, and cardiac computed tomography – should provide a broad spectrum of information, from diagnosis to clinical management of the major clinical profiles of the disease.

Incidence and Predictors of Infective Endocarditis in Mitral Valve Prolapse: A Population-Based Study

OBJECTIVE

To determine the incidence and predictors of infective endocarditis (IE) in a population-based cohort of patients with mitral valve prolapse (MVP).

PATIENTS AND METHODS

We identified all adult Olmsted County residents with MVP diagnosed by echocardiography from January 1989 to December 1998 and cross-matched them with the Rochester Epidemiology Project-identified Olmsted County cases of IE from January 1, 1986, through December 31, 2006. We retrospectively analyzed and de novo confirmed each IE case using the modified Duke criteria.

RESULTS

There were 896 Olmsted County residents with echocardiographically diagnosed MVP (mean age, 53±21 years; 565 women [63%]). The mean follow-up period was 11±5 years. The 15-year cohort risk of IE after MVP diagnosis was 1.1%±0.4% (incidence, 86.6 cases per 100,000 person-years; 95% CI, 43.3-173.2 cases per 100,000 person-years); thus, the age- and sex-adjusted relative risk of IE in patients with MVP was 8.1 (95% CI, 3.6-18.0) in comparison to the general population of Olmsted County (P<.001). There were no IE cases in patients without previously diagnosed mitral regurgitation (MR). Conversely, IE incidence was higher in patients with MVP with moderate, moderate-severe, or severe MR (289.5 cases per 100,000 person-years; 95% CI, 108.7-771.2 cases per 100,000 person-years; P=.02 compared with trivial, mild, or mild-moderate MR) and in patients with a flail mitral leaflet (715.5 cases per 100,000 person-years; 95% CI, 178.9-2861.0 cases per 100,000 person-years; P=.02 compared with no flail mitral leaflet).

CONCLUSION

The population-based incidence of IE in adults with MVP is higher than those previously reported in case-control, tertiary care center studies. Patients with MVP and moderate, moderate-severe, or severe MR or a flail mitral leaflet are at a notable risk of developing IE in comparison with those without MR.

Valvular heart disease and the military patient

Valvular heart disease refers to all inherited and acquired abnormalities impairing the function of one or more of the four cardiac valves. Pathology may be of the valve leaflets themselves, of the subvalvular apparatus or of the annulus or other surrounding structures that influences valve function. This paper examines the most common valve lesions, with specific reference to a military population; it focuses on detection and initial management of valve disease in a young adult population and specifically describes how the diagnosis and treatment of valve disease impacts military medical grading.

Prophylaxis to prevent infective endocarditis: to use or not to use?

The American Heart Association (AHA) published their revised guidelines in 2007 in which they markedly limited the recommendations for the use of antimicrobial prophylaxis for the prevention of infective endocarditis (IE), except for patients who are at highest risk of adverse outcomes. A recent focused update on valvular heart diseases changed the recommendation for antibiotic use for patients with many underlying heart conditions including mitral valve prolapse (MVP) which were considered as "low risk" heart defects. In this article, we argue that antibiotic prophylaxis should be considered until concrete clinical evidence is provided to dispute against the use of this strategy, especially for patients with MVP. This approach is cost efficient, and provides a chance to prevent a dreadful disease. We have also enlisted 2 clinical cases to support our argument. These are not uncommon clinical scenarios, and emphasize that IE can be fatal in spite of optimum treatment. Patients have the right to make the final decision, and they should be allowed to participate in choosing for or against this approach until adequate clinical evidence is available.

Pathology and pathogenesis of infective endocarditis in native heart valves

Infective endocarditis is an endovascular microbial infection of cardiovascular structures, including large intrathoracic vessels and intracardiac foreign bodies. The characteristic lesions consist of vegetations composed of platelets, fibrin, microorganisms, and inflammatory cells, as well as leaflet disruption. The commonly accepted pathogenetic theory is herein reported, from endothelial injury with deposition of noninfective sterile thrombotic vegetations to transient bacteremia with microorganism adhesion (injury-thrombus-infection theory). This review addresses the pathology of native valve endocarditis, including local (valvular and perivalvular destruction) and distal (embolism, metastatic infection, and septicemia) complications. Old and new cardiac conditions and patients at risk, predisposing to the occurrence of infective endocarditis, are then discussed. Particular emphasis is given to hidden bicuspid aortic valve and the need of early carrier identification for prophylaxis.

Mitral valve prolapse

Mitral valve prolapse is a common valvular abnormality that is the most common cause of severe non-ischaemic mitral regurgitation in the USA. The overall prognosis of patients with mitral valve prolapse is excellent, but a small subset will develop serious complications, including infective endocarditis, sudden cardiac death, and severe mitral regurgitation. We present a comprehensive review of mitral valve prolapse, examining normal mitral anatomy, the clinical and echocardiographic features of mitral valve prolapse, and the pathophysiology and genetics of the disorder. We discuss the contemporary management of both asymptomatic and symptomatic prolapse, with particular attention to the timing and technique of surgical repair. We conclude that echocardiography is the method of choice for diagnosing mitral valve prolapse, that clinical and echocardiographic features can predict which patients with prolapse are at highest risk for complications, and that mitral valve repair is the treatment of choice for symptomatic prolapse.

Mysteries of mitral valve prolapse. Proper treatment requires consideration of all clues

Although mitral valve prolapse is common in developed countries, its prevalence and its complications are much lower among the general population than was previously thought. No association has been conclusively documented for a myriad of neuropsychiatric symptoms previously speculated to be associated with mitral valve prolapse. Moreover, the prevalence of mitral valve prolapse does not appear to be affected by male or female sex. The most important management issues are mitral regurgitation and antibiotic prophylaxis for procedures that can cause bacteremia. For patients who are asymptomatic, reassurance becomes a critical component of treatment. If symptoms develop because of severe mitral regurgitation and decreased cardiac reserve, surgery may be required.

Anatomic explanation of mobile systolic clicks: implications for the clinical and echocardiographic diagnosis of mitral valve prolapse

An echocardiogram (echo) is often ordered for suspected mitral valve prolapse (MVP). Using echo as the gold standard, we conducted a meticulous physical examination on 61 patients with this referral diagnosis. Ninety percent of patients with negative physical examination and echo results for MVP had physical examination findings likely to have been misinterpreted as MVP by the referring physician. Redundant portions of the mitral valve apparatus were found in 57% of patients with MVP on our physical examination but not on echo. A carefully performed physical examination (including dynamic auscultation) can exclude MVP. Not all mobile systolic clicks are associated with anatomic echo prolapse; they can be generated by redundant chordae tendineae and, in the absence of echo prolapse, probably by redundant leaflets. Patients with mobile systolic clicks should have an echo to determine the portion of the spectrum of echo prolapse present and to determine risk stratification and management.

Pregnancy outcome and mitral valve prolapse

Mitral valve prolapse (MVP) comprises a large proportion of obstetric cardiac problems and has a general prevalence of 4%. We examined the obstetric outcome of patients with MVP delivered between 1988-1991 at the National University Hospital, Singapore. During this interval, deliveries totalled 16,755 of which 85 (0.51%) had maternal cardiac disease. Of these, 28 (32.9%) had echocardiographic evidence of non-myxomatous MVP. Ten patients (37.5%) had demonstrable mitral regurgitation and 4 (14.3%) had benign ventricular ectopics. All patients remained well throughout pregnancy. Gestation at delivery and use of analgesia did not differ significantly from non-cardiac patients. However, the labour induction rate was twice the department average at 17.9%. Twenty-four (85.7%) patients achieved vaginal delivery and 4 (14.3%) patients were delivered abdominally. All babies were liveborn. Eight patients (28.6%) did not receive antibiotic prophylaxis during labour and postpartum period and remained afebrile. The role of antibiotics in this category of patients is discussed. Patients with MVP without myxomatous valve changes may expect excellent pregnancy outcome.

Cost-effectiveness of infective endocarditis prophylaxis for mitral valve prolapse with or without a mitral regurgitant murmur

To assess the cost-effectiveness of prevention of infective endocarditis (IE) and to calculate cost-effectiveness of currently recommended regimens in patients with mitral valve prolapse (MVP), data on risk of death, complications, and health-care use, and cumulative incremental health-care costs due to the occurrence of IE were combined with data on the prevalence and manifestations of MVP, estimated years of life lost, and efficacy of antibiotic prophylaxis. Effectiveness and costs of standard endocarditis prophylaxis regimens were calculated per IE case prevented and years of life saved. Under the most likely scenario, oral amoxicillin prophylaxis for all MVP patients would prevent 32 cases of IE per million dental procedures at approximate costs of $119,000 per prevented case and $21,000 per year of life saved. Limiting prophylaxis to patients with mitral murmurs would prevent 80 cases of IE per million procedures at costs of about $19,000 per prevented case and $3,000 per year of life saved. Erythromycin prophylaxis was slightly less expensive than amoxicillin per benefit because of lower cost and lack of drug anaphylaxis, whereas intravenous ampicillin was 7 to 30 times more costly. Sensitivity analyses suggested that erythromycin prophylaxis might be cost-saving under some scenarios, whereas intravenous ampicillin use might cause net loss of life. Thus, prevention with oral antibiotics of the cumulative morbidity and incremental health care costs due to IE in MVP patients is reasonably cost-effective for MVP patients with mitral murmurs.

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.

Clinical and health care cost consequences of infective endocarditis in mitral valve prolapse

Although mitral valve prolapse (MVP) predisposes to infective endocarditis (IE), both the clinical consequences of IE and the increment in health care costs it imposes on patients with MVP remain uncertain. Accordingly, 21 MVP patients with IE and 41 age- and sex-matched control subjects with initially uncomplicated MVP were followed (95% complete) a mean of 8 years. Outcomes included death, complications, health care use and cumulative incremental costs. More MVP patients with IE died (25 vs 5%, p < 0.05), underwent valve surgery (40 vs 8%, p < 0.01), had heart failure (50 vs 5%, p < 0.01) or embolization (53 vs 11%, p < 0.01), underwent cardiac catheterization (40 vs 13%), and saw their physicians > 2 times per year (88 vs 33%). The cumulative incremental cost of IE (1990 dollars) was $46,132 per case. Thus, IE in patients with MVP causes considerable cumulative morbidity and incremental health care costs.

Mitral valve prolapse, panic disorder, and chest pain

Mitral valve prolapse is a common cardiac disorder that can readily be diagnosed by characteristic auscultatory and echocardiographic criteria. Although many diseases have been associated with mitral valve prolapse, most affected individuals have the primary form of the disorder. Mitral valve prolapse is an inherited condition commonly associated with myxomatous degeneration of the mitral valve and its support structures. Complications of mitral valve prolapse, including cardiac arrhythmias, sudden death, infective endocarditis, severe mitral regurgitation (with or without chordae tendineae rupture), and cerebral ischemic events, occur infrequently considering the wide prevalence of the disorder. Panic disorder is a specific type of anxiety disorder characterized by at least three panic attacks within a 3-week period or one panic attack followed by fear of subsequent panic attacks for at least 1 month. It too is a common condition with a prevalence and age and gender distribution similar to that of mitral valve prolapse. Panic disorder and mitral valve prolapse share many nonspecific symptoms, including chest pain or discomfort, palpitations, dyspnea, effort intolerance, and pre-syncope. Chest pain is the symptom in both conditions that most commonly brings the patient to medical attention. The clinical description of chest pain in patients with mitral valve prolapse is highly variable, possibly reflecting multiple etiologies. Chest pain in panic disorder is usually characterized as atypical angina pectoris and as such bears resemblance to the chest pain commonly described by patients with mitral valve prolapse. Multiple investigative attempts to elucidate the mechanism of chest pain in both conditions have failed to identify a unifying cause. Review of the literature leaves little doubt that mitral valve prolapse and panic disorder frequently co-occur. Given the similarities in their symptomatology, a high rate of co-occurrence is, in fact, entirely predictable. There is, however, no convincing evidence of a cause-effect relationship between the two disorders, nor has a single pathophysiologic or biochemical mechanism been identified that unites these two common conditions. Until specific biologic markers for these disorders are identified, it may be impossible to do so. The lack of a proven cause-and-effect relationship between mitral valve prolapse and panic disorder and the absence of a unifying mechanism do not diminish the clinical significance of the high rate of co-occurrence between the two conditions. Primary care physicians and cardiologists frequently encounter patients with mitral valve prolapse and nonspecific symptoms with no discernible objective cause who fail to respond to beta-blockade. Panic disorder should be considered as a possible explanation for symptoms in such patients.(ABSTRACT TRUNCATED AT 400 WORDS)

The changing pattern of infective endocarditis in childhood

Forty-eight cases of infective endocarditis (IE) that occurred in 42 patients with congenital heart disease were reviewed from 1970 through 1990 and were compared with a 20-year review of 108 cases diagnosed between 1953 and 1972. The review demonstrates that the natural history of IE in children has changed over the last 2 decades, with half of the cases occurring after surgery for congenital heart disease. In the postoperative group, 46% of patients had undergone valve replacement and 7 of these (29%) had a right ventricular to pulmonary artery valved conduit as the site for IE, suggesting significant additional risk in this setting. Among patients with nonsurgically treated congenital heart disease and IE, mitral valve prolapse has emerged as an important underlying heart lesion occurring in 29% of patients. The bacterial spectrum has shifted, with a significant increase in the incidence of uncommon causative organisms. Mortality has continued to decline with survivorship of 90% in this series.

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 high-risk and low-risk subgroups of patients with mitral-valve prolapse

Mitral-valve prolapse is a common cardiac valvular disorder with a wide range of severity and diverse clinical outcomes. The lack of a standard definition of mitral-valve prolapse may explain the variation in reported complication rates. To identify high-risk and low-risk subgroups, we retrospectively analyzed clinical and two-dimensional echocardiographic data from 456 patients with mitral-valve prolapse. Mitral-valve prolapse was defined on the basis of echocardiographic findings as systolic displacement into the left atrium of one or both leaflets beyond the plane of the mitral annulus in the parasternal long-axis view. Two groups of patients were compared: those with thickening of the mitral-valve leaflets and redundancy (designated the classic form; n = 319) and those without leaflet thickening (designated the nonclassic form; n = 137). The two groups were similar in age and sex ratio. Complications or a history of complications was more prevalent in the classic than the nonclassic form: infective endocarditis, 3.5 percent and 0 percent, respectively (P less than 0.02); moderate-to-severe mitral regurgitation, 12 percent and 0 percent (P less than 0.001); and the need for mitral-valve replacement, 6.6 percent and 0.7 percent (P less than 0.02). However, the frequency of stroke was similar in the two groups: 7.5 percent and 5.8 percent (P not significant). We conclude that in a selected population of patients with mitral-valve prolapse, those with the classic form (leaflet thickening and redundancy) are at higher risk than those without these features for the infectious and hemodynamic complications of mitral-valve prolapse, but not for stroke.

Reconsideration of echocardiographic standards for mitral valve prolapse: lack of association between leaflet displacement isolated to the apical four chamber view and independent echocardiographic evidence of abnormality

Mitral valve prolapse by current echocardiographic criteria can be diagnosed with surprising frequency in the general population, even when preselected normal subjects are examined. In most of these individuals, however, prolapse is present in the apical four chamber view and absent in roughly perpendicular long-axis views. Previous studies have shown that systolic annular nonplanarity can cause apparent prolapse in the four chamber view without actual leaflet displacement above the most superior points of the anulus, and there is evidence for such nonplanarity in vivo. It is then reasonable to ask whether superior leaflet displacement limited to the four chamber view has any pathologic significance or complications. The purpose of this study, therefore, was to address the following hypothesis: that patients with superior leaflet displacement confined to the four chamber view have no higher frequency of associated echocardiographic abnormalities than do patients without displacement in any view. Such abnormalities, which would provide independent evidence of mitral valve pathology or dysfunction, include leaflet thickening, left atrial enlargement and mitral regurgitation. Leaflet displacement was measured in the parasternal long-axis and apical four chamber views in 312 patients who were studied retrospectively and selected for the absence of forms of heart disease other than mitral valve prolapse. Leaflet thickness and left atrial size were measured and mitral regurgitation was graded. Patients with leaflet displacement limited to the four chamber view were no more likely to have associated abnormalities than were patients without displacement in any view (0 to 2% prevalence, p greater than 0.5). In contrast, patients with leaflet displacement in the long-axis view were significantly more likely to have associated abnormalities (12 to 24%, p less than 0.005), the frequency of which increased with the extent of leaflet displacement in that view (p less than 0.0001). These results suggest that displacement limited to the apical four chamber view is, in general, a normal geometric finding unassociated with echocardiographic evidence of pathologic significance.

Mitral valve prolapse

Mitral valve prolapse is a common mitral valve disorder manifested clinically as a midsystolic click and/or a late systolic murmur (the click-murmur syndrome) and pathologically as billowing or prolapsing mitral leaflets (the floppy valve syndrome). Not only is it one of the two most common congenital heart diseases and the most common valve disorder diagnosed in the United States, but it is also prevalent throughout the world. Mitral valve prolapse may be associated with a variety of other conditions or diseases. Diagnosis of mitral valve prolapse should be made on clinical grounds and, if necessary, supported by echocardiography. The majority of patients with mitral valve prolapse suffer no serious sequelae. However, major complications such as disabling angina-like chest pains, progressive mitral regurgitation, infective endocarditis, thromboembolism, serious arrhythmias, and sudden death may occur. Unless these serious complications occur, most of the patients with mitral valve prolapse need no treatment other than reassurance, including those with atypical chest pain or palpitation unconfirmed by objective data. Therapy with a beta-blocker for disabling chest pain and/or arrhythmias and antiplatelet therapy for cerebral embolic events may be indicated. In occasional patients with significant mitral regurgitation surgery may be necessary.