401
edits
Valvular Heart Disease: Difference between revisions
no edit summary
No edit summary |
No edit summary |
||
| Line 128: | Line 128: | ||
== Prognosis == | == Prognosis == | ||
Aortic valve stenosis has a severe prognosis when any symptoms are present, with survival rates of only 15–50% at 5 years. Strongest predictors of poor outcome in the elderly population are high New York Heart Association (NYHA) class (III/IV), associated mitral regurgitation and left ventricular dysfunction. Survival is only 30% at 3 years with the combination of these three factors. | Aortic valve stenosis has a severe prognosis when any symptoms are present, with survival rates of only 15–50% at 5 years. Strongest predictors of poor outcome in the elderly population are high New York Heart Association (NYHA) class (III/IV), associated mitral regurgitation and left ventricular dysfunction. Survival is only 30% at 3 years with the combination of these three factors. | ||
== Bicuspid Aortic valve == | |||
Bicuspid Aortic valve disease affects as many as 1-2% of the population, and is the most frequent congenital cardiovascular malformation in humans. <cite>Fedak</cite> | |||
A bicuspid aortic valve may be part of a phenotypic continuum of congenital aortic valve disorders, associated with unicuspid valves, bicuspid valves, the normal tricuspid valves and the rare quadricuspid forms. Understanding of the pathogenesis of aortic valve malformation remains incomplete. | |||
Bicuspid aortic valves are three to four times more common in men than in women. Bicuspid aortic valve disease results from abnormal cusp formation during valvulogenesis, but coexisting genetic abnormalities of the aorta and proximal coronary vasculature are often present. Moreover, nonvalvular findings occur in up to 50% of patients with bicuspid aortic valves. Associated findings are aortic dilation, aneurysms and dissection. | |||
During valvulogenesis, adjacent cusps of the bicuspid valve fuse to form a single aberrant cusp. This fusion results in large leaflet, yet smaller than 2 normal cusps, with most often a central raphe or ridge. Fusion of the right coronary and noncoronary cusps is associated with cuspal pathology. Fusion of the right and left coronary cusps is associated with coarctation of the aorta. | |||
Although endocarditis can be a devastating complication of bicuspid aortic valve disease, straightforward bicuspid aortic valve disease is no longer an indication for bacterial endocarditis prophylaxis according to the ACC/AHA practice guidelines. The risk of endocarditis is felt to be low in patients with straightforward bicuspid aortic valve disease. An exception to this recommendation is a patient with a prior history of endocarditis. <cite>Nishimura</cite> | |||
=== Clinical Presentation === | |||
In infancy, bicuspid aortic valve disease is often asymptomatic. By adolescence an estimate 1 of 50 children born with these abnormalities will have clinically significant obstruction or regurgitation. <cite>Bonow</cite> | |||
Complications of bicuspid aortic valve disease are common in adulthood <cite>Tzemos</cite>. The abnormal shear stress leads to valve calcification and further aortic root dilation has been reported. <cite>Bonow2</cite> The most common complication is aortic stenosis, caused by premature fibrosis, stiffening, and calcium deposition. The majority of patients under 65 years of age with significant aortic valve stenosis have bicuspid aortic valve disease. A more rare complication of bicuspid aortic valve disease is aortic regurgitation. 15% of all cases of aortic regurgitation in the Euro Heart survey had bicuspid aortic valve disease. On auscultation, an ejection sound can be audible, best heard at the apex. There may be associated murmurs of aortic stenosis, incompetence, or coarctation of the aorta when these lesions are present. | |||
=== Diagnostic options === | |||
==== Imaging ==== | |||
Echocardiography is used to confirm the diagnosis of bicuspid aortic valve disease. Reported sensitivities and specificities of echocardiography for detecting BAV anatomy are 92% and 96% respectively. To establish the diagnosis, visualization of the aortic in systole in the short-axis view is essential. During diastole, the raphe can make the valve appear trileaflet. In the long-axis view, the valve often has an eccentric closure line and there is doming of the leaflets. Transesophageal echocardiography may improve visualization of the leaflets in case of inconclusive visualization during transthoracic echocardiography. The thoracic aorta is visualized by alternative imaging modalities such as cardiac magnetic resonance imaging (MRI) or computer tomography (CT). Both cardiac MRI and CT images can help to confirm the bicuspid anatomy of the aortic valve. | |||
In all patients, serial transthoracic echocardiography should be performed to evaluate the valve and disease progression. Annual cardiac imaging is recommended for patients with significant valve lesions or with aortic root diameters >40 mm. Complete imaging of the thoracic aorta should be performed periodically for surveillance. <cite>SiuSilversides</cite> | |||