The same diseases that affect the mitral and tricuspid valves may also affect the aortic valve. According to the pathophysiological triad ( Table 21-1 ), a clear distinction should be made between etiology, lesions, and dysfunctions.
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ETIOLOGY
Aortic valve diseases involve either the leaflets themselves (primary valve diseases) or the leaflets’ supporting structures (secondary valve diseases) ( Table 21-2 ). The three most common etiologies ( Fig. 21-1 ) are bicuspid valve malformation (a) , rheumatic valvular disease (b) , and calcified aortic valvular disease (c) . In developing countries rheumatic valvular disease remains the predominant etiology, while in developed countries valve sclerosis leading to calcific aortic stenosis is seen with increasing frequency because of the aging of the population. Besides the characteristic gross lesions recognized during surgery, several factors may contribute to the determination of the cause of valve disease, such as age, medical history, geographical origin, socioeconomic conditions, and clinical presentation. This information and echocardiography findings make it possible to determine the etiology of most aortic valve diseases before the surgical intervention.
Primary Aortic Valve Diseases
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Secondary Aortic Valve Diseases
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Etiologic determination is important to assess the feasibility of valve reconstruction, the long-term prognosis, and the prescription of appropriate medical therapy.
LESIONS
Any of the diseases previously listed can cause one or several lesions that may affect one or several components of the aortic root ( Table 21-3 ). They may be associated with mitral and tricuspid valve lesions, which should be systematically searched for during the operation by transesophageal echocardiography and even direct surgical inspection.
| Annulus | Dilatation |
| Abscess | |
| Calcification | |
| Leaflets | Distension |
| Tear, perforation | |
| Vegetations | |
| Thickening | |
| Calcification | |
| Commissures | Rupture |
| Fusion | |
| Calcification | |
| Aorta | Dilatation |
| Aneurysm | |
| Dissection | |
| Calcification |
DYSFUNCTION: THE “FUNCTIONAL CLASSIFICATION”
The “functional approach” by echocardiography provides accurate information on leaflet mobility to the surgeon, whose primary aim is to try to restore proper valve function.
Aortic Valve Regurgitation
Valve regurgitation is classified according to the amplitude of leaflet motion and the diastolic position of the free edge of each leaflet in relation to the annular plane, which serves as a reference point. Three types of aortic valve dysfunction can be described ( Table 21-4 ).
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Type I: Aortic valve regurgitation with normal leaflet motion . In type I aortic valve regurgitation, the course of the leaflets between systole and diastole has a normal amplitude and the free edge of the leaflets during diastole is well positioned above the annular plane ( Fig. 21-2 ). The regurgitation results from a lack of coaptation between leaflets, a consequence of annular dilatation . It may also result from leaflet perforation or vegetations .
FIGURE 21-2
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Type II: Aortic valve regurgitation with leaflet prolapse . Typically, leaflet prolapse is a valve dysfunction in which the free edge of a leaflet is displaced underneath the annular plane during diastole. The resulting lack of leaflet apposition produces a regurgitant jet, which runs obliquely under the nonprolapsing leaflets.
