Marfan's Syndrome
Definition
Marfan's syndrome is a genetically inherited connective tissue disease that appears in 4-6 of every 100,000 people. There is 50% incidence of transmittance to offspring, with no sex-linked characteristics. Marfan's syndrome causes deformations and defects in several body systems, most notably the ocular, skeletal, and cardiovascular. Diagnosis is based only upon clinical observation, with symptoms of two or more of the common conditions required for confirmation.
Pathology
Mitral valve:
the cusps of the valve become redundant and elongated, causing MV prolapse, a condition more common in female patients. The mitral annulus may become dilated, causing MR. Chordae tendinae can stretch and rupture. Mitral valve deformations are often associated with aortic root dilatation.
Aortic root:
the sinuses of Valsalva are dilated at birth. Aortic regurgitation occurs with a valvular diameter of 50 mm. Regurgitation is absent at diameters above 60mm. The aortic root becomes dilated and is often coexistent with aortic dissection. The risk of dissection increases as the diameter of the aorta increases.
Aortic Dissection:
dissection usually begins above the coronary ostia and extend the lenth of the aorta
(DeBakey Type I). Only 10% of Marfan's patients present with Type III dissections,
and only rarely to dissections involve only the abdominal aorta.
Dysrhythmias:
Marfan's syndrome is usually associated with ventricular and supraventricular arrythmias. THe SV type are most often associated with MR.
Clinical Manifestations
Skeletal manifestations of Marfan's syndrome are the most obvious. Patients are tall and lanky, with long extremities. Scoliosis and joint hypermobility are common. There are also associated sternal and spinal deformities.
Ocular defects would include myopia and retinal detachment. These affect 70% of Marfan's patients.
Marfan's syndrome may also cause attention deficit disorder, hyperactivity, and verbal discrepancies through its effects on the CNS.
The most significant effects are those on the cardiovascular system, seen in 98% of Marfan's patients. The pathology includes mitral valve prolapse, endocarditis, dysrhythmias, dilatation of the mitral annulus, mitral regurgitation, tricuspid valve prolapse, aortic regurgitation, aortic dissection, and dilatation of the aortic root.
Medical and Surgical Interventions
Regular echocardiograms are recommended to monitor changes in the valves and changes in the diameter of the aorta. Routine endocarditis prophylaxis is required before any dental or other potentially infectious procedures.
Patients with Marfan's syndrome have restricted activities and are banned from any contact sports. Mitral valve repair/replacement is often necessary, and is usually accompanied by an aortic root replacement. Marfan's patients have an increased incidence of prosthetic valve failure due to the connective tissue degeneration that causes the disease. Aortic root surgery is usually performed when the dimension exceeds 60 mm. A composite graft is utilized in most cases, but success is limited to susceptibility of these patients to endocarditis and anticoagulation abnormalities. Surgical interventions are made more difficult due to the sternal deformity that is associated with Marfan's syndrome. This makes approach by median sternotomy nearly impossible.
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