Pathophysiology, Valve Analysis, and Surgical Indications

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.

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.

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.