Since she had a history of Marfan's syndrome and was in her last trimester of pregnancy, she was referred for echocardiography, which showed mitral valve prolapse with minimal mitral regurgitation. The shape of the aorta was consistent with Marfan's syndrome. Descending aorta was not dilated and the diameter measured 3.3 cm at sinus of Valsalva and 2.6 cm in ascending aorta. Chamber sizes and wall thickness were normal. Left ventricular ejection fraction was greater than 60%.
Other Studies: ECG revealed sinus rhythm and an incomplete right bundle branch block.
NOTES:
A case of Marfan's
Hospital Course: Since she had no dilatation of the aorta and was asymptomatic, she was followed by the high-risk obstetrics service, with plans to undergo a normal vaginal delivery. She was started on Beta-blocker therapy with plans to continue this through delivery.
Marfan's syndrome is an autosomal dominant inherited abnormality which has been localized to a mutation in Chromosome 15. This disorder is characterized by muscular and ocular and cardiovascular features including mitral valve prolapse, mitral regurgitation, aortic insufficiency and aortic root dilation, which can progress and be complicated by dissection. The mean age for cardiovascular events is 32 years. Small retrospective studies have demonstrated an increased risk of aortic dissection in women with Marfan's syndrome who become pregnant. In women with preconception aortic dilation the risk is greater due to the changes of cardiac output and plasma volume that occur by the 6th week of pregnancy and the increased stress during labor. Vaginal delivery is acceptable in patients with Marfan's and epidural anesthesia may be helpful in lowering the blood pressure at the time of delivery. However if the aortic root is greater than 4 cm a cesarean section should be considered.
Echocardiography has proven useful to screen for preconception aortic dilatation to identify women with Marfan's at higher risk for aortic complication. If the aortic root is less than 4 cm , the risk of a life threatening aortic event during pregnancy appears to be at baseline for all women. The rate of aortic dissection dramatically increases if the aortic root is greater than 5.5 cm. Monthly transthoracic echocardiography while pregnant is useful to monitor for progressive aortic root dilatation, which may be a precursor to aortic dissection. Long-term therapy with beta-blockers to control hypertension has been shown to slow the rate of aortic dilatation in patients with Marfanıs syndrome. Beta-blockers can be used safely from mid-trimester until labor particularly if there is evidence of aortic dilatation.
Antibiotic prophylaxis is not necessary since the rate of endocarditis during pregnancy and delivery is not increased in most studies. However prophylactic antibiotics should be considered for pregnant women with Marfan's syndrome and mitral prolapse with mitral regurgitation.
Further information can be obtained at www.marfan.org
Selected readings:
Shores, J, Berger KR and Murphy EA et al Progression of aortic dilatation and the benefit of long term beta-adrenergic blockade in Marfanıs syndrome. NEJM 1994, 330:1335-1341
Lipscomb KJ, Smith JC, Clarke B et al Outcome of pregnancy in women with Marfanıs syndrome. British J of Obstetrics and Gyn. 104:201-206 Feb 1997
Simpson LL, Athanassious AM, DıAlton ME. Marfanıs syndrome in pregnancy. Current Opinion in Obstetrics and Gyn. 9:337-341, 1997