- Bicuspid aortic valve
Name = Bicuspid aortic valve
DiseasesDB = 1392
ICD9 = ICD9|746.4
OMIM = 109730
eMedicineSubj = ped
eMedicineTopic = 2486
A bicuspid aortic valve is a defect of the aortic valve that results in the formation of two leaflets or cusps instead of the normal three. Normally only the mitral valve has two cusps (instead of three); situated between the
left atriumand left ventricle. Valves ensure the unidirectional flow of blood from the atrium to the ventricles, or the ventricles to the major arteries and veins.
About 1-2% of the population have bicuspid aortic valves, although the condition is nearly twice as common in males.
It is more common than any other congenital cardiac anomaly.cite journal |author=Tzemos N, Therrien J, Yip J, "et al" |title=Outcomes in adults with bicuspid aortic valves |journal=JAMA |volume=300 |issue=11 |pages=1317–25 |year=2008 |month=September |pmid=18799444 |doi=10.1001/jama.300.11.1317 |url=http://jama.ama-assn.org/cgi/pmidlookup?view=long&pmid=18799444]
Bicuspid aortic valve has been found to be an inheritable condition, with a demonstrated association with
Notch 1.cite journal |author=Garg V, Muth AN, Ransom JF, "et al" |title=Mutations in NOTCH1 cause aortic valve disease |journal=Nature |volume=437 |issue=7056 |pages=270–4 |year=2005 |pmid=16025100 |doi=10.1038/nature03940] Familial clustering as well as isolated valve defects have been documented. The incidence of bicuspid aortic valve can be as high as 10% in families affected with the valve problem. Other congential heart defects are associated with bicuspid aortic valve at various frequencies.
In many cases, the condition will cause no problems. [cite web |url=http://www.americanheart.org/presenter.jhtml?identifier=991 |title=Ask the Pediatric Cardiologist - Bicuspid Aortic Valve |accessdate=2007-08-08 |format= |work=] However, especially in later life, a bicuspid aortic valve may become calcified, which may lead to varying degrees of severity of
aortic stenosisand aortic regurgitation, which will manifest as murmurs. If these become severe enough, they may require heart surgery.
The condition can be associated with a
heart murmurlocated at the right 2nd intercostal space. Oftentimes there will be differences in blood pressures between upper and lower extremities. The diagnosis can be assisted with echocardiography and chest x-ray. "Rib notching" is often noted on chest x-ray.
Most patients with bicuspid aortic valve whose valve becomes dysfunctional will need careful follow-up and potentially valve replacement in their third or fourth decade of life.
Patients with bicuspid aortic valve should be followed by cardiologist or cardiac surgeon with specific interest in this valve pathology.
Average lifespan is similar to that of those without the anomaly.cite journal |author=Michelena HI, Desjardins VA, Avierinos JF, "et al" |title=Natural history of asymptomatic patients with normally functioning or minimally dysfunctional bicuspid aortic valve in the community |journal=Circulation |volume=117 |issue=21 |pages=2776–84 |year=2008 |month=May |pmid=18506017 |doi=10.1161/CIRCULATIONAHA.107.740878 |url=http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=18506017]
Another important fact is the aorta of patients with bicuspid aortic valve is not normal. The aorta of a patient with a bicuspid aortic valve does not have the same histological characteristics of a normal aorta. The tensile strength is reduced. These patients are at a higher risk for
aortic dissectionand aneurysmformation of the ascending aorta. The size of the proximal aorta should be evaluated carefully during the work-up. The initial diameter of the aorta should be noted and periodic evaluation with CT scan (every year or sooner if there is a change in aortic diameter) should be recommended. Therefore, if the patient needs surgery, the size of the aorta will determine what type of surgery should be offered to the patient. Additionally, patients with bicuspid aortic valve are at higher risk of aortic coarctation, an abnormal narrowing of the thoracic aorta.
* [http://bicuspidfoundation.com/ Bicuspid Aortic Foundation Homepage]
* [http://www.csmc.edu/3893.html Cedars Sinai Heart Center - Bicuspid Aortic Disease]
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