US Pharm. 2008;33(2):28-33
Mitral valve prolapse (MVP) is
a condition that affects nearly 15 million Americans.1 It is the
most common cause of severe, nonischemic mitral regurgitation in the United
States. Its cause is unknown, but in some patients it appears to be a
genetically determined collagen tissue disorder. Mitral valve prolapse
encompasses a broad spectrum of severity. Some patients with this condition
are asymptomatic, while others experience an array of symptoms that can be
life altering. The prognosis of this condition is excellent, but a small
subset of patients will develop serious complications.2 Pharmacists
can play a role in managing patients with MVP by providing needed reassurance
of the benign prognosis for asymptomatic patients as well as by offering
proper medication counseling to those patients who require medication
mitral valve itself is important in managing MVP and can help lead to
effective treatment. The mitral valve of the heart is a complicated apparatus
and is located between the left atrium and the left ventricle. The mitral
valve has two flaps. In some people, one or both of the mitral valve flaps are
enlarged and do not close properly. When the left ventricle contracts, the
valve's flaps bulge (prolapse) backward into the left atrium. This heart
abnormality is called MVP. Mitral valve prolapse is a common source of valve
repair and replacement for patients with isolated mitral regurgitation in the
U.S. It is important to note that MVP is the most common form of valvular
The term mitral valve
prolapse describes a defect in the mitral valve of the heart. A different
term, mitral valve prolapse syndrome, is commonly used to indicate the
presence of MVP and an assemblage of other physical abnormalities such as
autonomic dysfunction, palpitations, and pectus excavatum. These other
physical abnormalities can result in a variety of unrelated symptoms. It is
estimated that MVP syndrome affects between 3% to 6% of adults in the U.S.
1 This syndrome can often be debilitating to patients and extremely
frustrating for physicians to properly manage.
SIGNS AND SYMPTOMS
Mitral Valve Prolapse
prolapse is typically diagnosed during a routine physical exam with a
stethoscope. Most patients with MVP are female. It affects individuals of
differing ages but most commonly those patients between the ages of 14 and 30.
Patients with MVP share a hallmark physical finding of a midsystolic click and
a late systolic murmur.3 Interestingly, many patients with MVP
appear to be part of a connective tissue phenotypic spectrum. Often, these
patients have "tall, thin habitus, thoracic cage deformity and joint
hypermobility as well as low blood pressure."4,5 Most patients
with MVP do not have symptoms, do not have problems, and will not need
treatment. Those patients who do complain of symptoms report chest discomfort,
anxiety, fatigue, and dyspnea. It is inconclusive if these symptoms are
actually due to the prolapse of the mitral valve or if they are coincidental
occurrences.1 For symptomatic patients, the most common reason for
symptoms is the leakage of blood backward through the valve. This is known as
regurgitation. Patients who experience regurgitation often have symptoms
of a racing or irregular heartbeat, dizziness, lightheadedness, fatigue, chest
pain, and shortness of breath.3
Mitral Valve Prolapse
Many patients who
present with MVP also exhibit symptoms that appear to be unrelated. As
mentioned earlier, these patients are often diagnosed with a condition known
as MVP syndrome. Mitral valve prolapse syndrome is usually diagnosed after a
patient has seen a multitude of specialists. Patients present with an array of
symptoms that are often cause for misdiagnosis. These patients appear to have
an autonomic or neuroendocrine system imbalance. This condition is often
referred to as dysautonomia (malfunction of the autonomic nervous
system). The autonomic nervous system is complex and controls necessary
functions such as respiration, heartbeat, blood pressure, vision, and
digestion. When the autonomic system is out of balance, it can cause a
multitude of symptoms, including panic attacks, anxiety, fatigue,
palpitations, migraines, hypotension, and irritable bowel syndrome. It has
been hypothesized that there is a potential role of the renin angiotensin
system in the pathogenesis of MVP syndrome. Investigations are being conducted
to examine the possible relation between the A-C polymorphism of the AT
1 gene and MVP syndrome. One study has found a link.4
Diagnosis of MVP syndrome is
determined by physical examination, a careful medical history, and, in most
cases, an echocardiogram. Symptoms of MVP syndrome do not typically present
before the age of 14.4,5 It is important to note that patients
without MVP often present with similar dysautonomic symptoms. It is unclear if
this condition is related solely to a valvular abnormality or if there is a
genetic link involved.2
electrocardiogram may provide some valuable information in patients with MVP,
patients typically present with a normal ECG. If there is an abnormality, it
will present as ST-Tñwave depression or T-wave inversion in the inferior leads
(II, III, and VF). Occasionally, the ECG will show supraventricular or
ventricular premature contractions. Electrocardiograms may be useful for
documenting arrhythmias in patients who experience palpitations.3
and Doppler echocardiography is the most useful, noninvasive test for
diagnosing MVP. It is effective in identifying the abnormal position and
prolapse of the mitral valve leaflets.5 MVP can be diagnosed when
one or both mitral leaflets demonstrate at least 2 mm of systolic displacement
superior to a line connecting the annular hinge points in a long-axis view.
2 The diagnosis of MVP is even more certain when the echocardiography
shows a leaflet thickness greater than 5 mm. Echocardiograms are helpful in
detecting left atrial size, left ventricle size, and function. The
echocardiogram is also helpful in determining the extent of mitral leaflet
redundancy for patients at risk for developing complications.5
Although the echocardiogram is
a confirmatory test for diagnosing MVP, it may not always be abnormal. It is
recommended that all patients with MVP have an initial echocardiogram to
assess left atrial and left ventricle size, left ventricle function, and
mitral leaflet movement and thickness.1 Sequential echocardiograms
are not usually deemed necessary in asymptomatic patients with MVP unless such
patients present with clinical indications that their condition is worsening.
5 Using echocardiography as a screening tool for MVP is not recommended
for patients who do not have a systolic click or murmur on several
auscultatory examinations, regardless of whether the patient is symptomatic.
The most frequent and important
complication of MVP is a condition known as mitral regurgitation (MR). In this
condition the mitral valve is particularly leaky and allows excessive blood to
leak backwards into the left atrium.6 Physical examination is not
always reliable in diagnosing MR and, in fact, cannot accurately measure the
severity of MR.7 The gradual progression of MR in patients with MVP
may result in increasing dilation and dysfunction of the left atrium and left
ventricle. MR that becomes severe can lead to cardiac arrhythmias, congestive
heart failure, and an increased risk of sudden death.7 Patients who
suffer from severe MR are also at an increased risk of developing infective
endocarditis, which can be fatal.8,1
Although MVP appears to be
prevalent more among women, males who are older than 50 years do present with
MVP. These men have a threefold higher risk than women of ultimately needing
surgery for severe MR. Patients with hypertension and a high body-mass index
are at higher risks for developing severe MR.3 Age is also of
importance when considering who is at greater risk for developing severe MR.
The prevalence of severe MR is infrequent before the fifth decade of life.
2 Echocardiography is used to diagnose severe MR. Patients whose
echocardiogram reveals thickened leaflets, posterior leaflet prolapse, and
increased left ventricular dimensions are at greater risk for development of
severe MR. Contrastingly, patients with thin leaflets have a lower risk of
developing severe MR.
Patients with MR may be
asymptomatic for years. The average interval from diagnosis to the onset of
symptoms is 16 years.7 Most available data focus on patients with
severe regurgitation. There are few data on the rate of progression of disease
with mild to moderate regurgitation. The progression may be slow and insidious
or it may be abrupt. Abrupt progression is indicative of a chordal rupture,
which leads to flail leaflet. Patients with severe symptomatic MR have a poor
clinical outcome. Survival rates are 33% at 8 years in the absence of surgical
intervention. Most deaths are related to heart failure, but there is
significant incidence of sudden death.7
inflammation of the endocardium or lining layer of the heart, and the most
common heart structures involved are the valves. Endocarditis is either
infective or noninfective depending on the source of the problem. Patients who
develop infective endocarditis are typically infected with staphylococci or
streptococci.9 Individuals with suspected endocarditis often
require echocardiographic evaluation to detect and characterize the
hemodynamic and pathologic consequences of type of endocarditis. Patients
developing endocarditis typically exhibit major cardiac complications. One
complication includes damaged cardiac valves, including the mitral valve. The
functional and structural integrity of these valves may be completely
destroyed by the invading infectious organism. Patients who develop
endocarditis require antimicrobial therapy, and in some instances surgical
management is warranted.9
Patients with MVP who
experience regurgitation are at a three- to eightfold increased risk for
developing infective endocarditis. Predictors of increased risk for developing
infective endocarditis include males older than 45 years, the presence of a
systolic murmur, and leaflet thickening and redundancy.2 Because
endocarditis is associated with substantial morbidity and mortality, patients
with MVP regurgitation are encouraged to take antibiotics prior to dental
procedures and certain types of surgery. By taking prophylactic antibiotic
therapy, patients are less likely to develop infective endocarditis.3
In a patient with MVP and the absence of regurgitation, the incidence of
infective endocarditis is similar to that of the general population, and
therefore antibiotic prophylaxis is not warranted.2
TREATMENT AND FOLLOW-UP
Most patients with
MVP are asymptomatic and are not at high risk for serious complications.
Practitioners should manage these patients by providing reassurance of their
benign prognosis. Patients should be encouraged to live a healthy lifestyle
and exercise regularly.1
Asymptomatic patients with
mild or no regurgitation can be clinically evaluated every 3 to 5 years.
Sequential echocardiograms are not deemed necessary unless cardiovascular
symptoms develop or if progression of MR is suspected.1
MVP patients who
demonstrate palpitations associated with tachycardia, increased adrenergic
symptoms, chest pain, anxiety, or fatigue often respond well to therapy with
low-dose, beta-blocking agents. Symptoms related to orthostatic changes, such
as postural hypotension, can be treated with increased fluid and salt intake.
If patients experience severe orthostatic symptoms, mineralocorticoid therapy
may be warranted.1
According to the guidelines of
the American College of Cardiology/American Heart Association, symptomatic MVP
patients with histories of transient ischemic attacks may benefit by being
placed on aspirin therapy (80-325 mg/day). Symptomatic MVP patients with
histories of stroke and recurrent transient ischemic attacks while on aspirin
therapy are advised to take long-term anticoagulation therapy such as warfarin.
Patients with MVP syndrome are
often encouraged to take measures to correct their autonomic dysfunction.
Certain measures would include proper diet, limiting caffeine intake, and
increasing exercise. It has been suggested that heavily symptomatic MVP
patients have low serum magnesium levels. These patients also often present
with hyperadrenergic activity. Studies have demonstrated that when this is the
case, magnesium supplementation may lead to improvement of symptoms. Magnesium
supplementation may also decrease catecholamine excretion and reduce overall
weakness, chest pain, dyspnea, palpitations, and anxiety.10
Symptomatic patients may find symptom improvement by taking 200 to about 800
mg of magnesium a day. One common side effect of magnesium is diarrhea. If a
patient experiences diarrhea, he or she should decrease the daily amount of
magnesium. In general, magnesium is considered a safe mineral, but people with
heart problems or kidney problems should be cautious of taking too much.
patients with severe MR should be evaluated for mitral valve repair, and
replacement is sometimes indicated. Valvular surgery is recommended for
patients with severe MR accompanied by atrial fibrillation or pulmonary
hypertension. There are different types of surgery options for patients.
Mitral valve repair and mitral valve replacement are two options. There is a
consensus in the medical literature that mitral valve repair is preferred over
mitral valve replacement.
Mitral valve repair is a
surgical procedure that preserves the patient's mitral valve. The surgeon
attempts to modify the original mitral valve. This is called valvuloplasty,
which eliminates backward blood flow. Surgeons also sometimes repair the valve
by tightening or replacing the ring around the valve. This is called
annuloplasty. Mitral valve repair has many advantages over valvular
replacement. Patients undergoing mitral valve repair have lower operative
mortality, better long-term survival, and lower risks of thromboembolic events.
Mitral valve replacement is
performed when mitral valve repair is not possible. In this procedure, the
surgeon removes the damaged mitral valve and replaces it with a prosthetic
valve. There are two types of prosthetic valves used, mechanical valves and
tissue valves. Mechanical valves are made of metal. Patients who choose this
route will be required to take an anticoagulant medication for the remainder
of their lives. Tissue valves are made from biological tissue such as pig's
heart valves, and patients are not required to take an anticoagulant
medication. Typically, mechanical valves last longer than tissue valves.
prolapse is not a preventable disorder. Patients with MVP can lead normal,
productive, symptom-free lives. The prognosis for someone with uncomplicated
MVP (without regurgitation) is excellent. Patients who present with MVP often
differ in disease severity. Some patients are asymptomatic, while others
experience more extreme symptoms that may be life altering. One major part of
managing patients with MVP is providing reassurance, because most patients are
asymptomatic and not at high risk for complications. Health care providers
should reassure patients with mild or no symptoms of the benign prognosis. All
patients with MVP are encouraged to lead a normal lifestyle that includes a
regular exercise plan. Patients who have evidence of disease complications,
such as regurgitation, are at increased risk for mortality and morbidity.
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management of mitral valve prolapse. Am Fam Physician.
2. Hayek E, Gring C, Griffin B.
Mitral valve prolapse. Lancet. 2005;365:507-518.
3. Mayo Clinic Web site. Available
at: www.mayoclinic.com. Accessed November 5, 2007.
4. Szombathy T, et al. Angiotensin
II type 1 receptor gene polymorphism and mitral valve prolapse syndrome. Am
Heart J. 2000;139:101-105.
5. Maron B, et al. Task Force 4: HCM
and other cardiomyopathies, mitral valve prolapse, myocarditis and Marfan
syndrome. J Am Coll Cardiol. 2005:40:1340-1345.
6. American Heart Association Web
site. Available at americanheartheart.org. Accessed November 6, 2007.
7. Otto C. Evaluation and management
of chronic mitral regurgitation. N Engl J Med. 2001;345:740-746.
8. Jonkaitiene R, Benetis R,
Ablonskyte-Dudoniene R, Jurkevicius R. Mitral valve prolapse: diagnosis,
treatment and natural course. 2005;41:325-334.
9. Lester S, Wilansky S.
Endocarditis and associated complications. Crit Care Med.
10. Lichodziejewska B, et al.
Clinical symptoms of mitral valve prolapse are related to hypomagnesemia and
attenuated by magnesium supplementation. Am J Cardiol. 1997:79:768-772.
11. St John Sutton M, Weyman A.
Mitral valve prolapse prevalence
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and complications: an
ongoing dialogue. Circulation. 2002;106:1305-1307.