[Diagnostic approach and optimal treatment of aortic valve stenosis].
The slow progression of valvular aortic stenosis enables the left ventricular myocardium to adapt itself to the increasing afterload. When myocardial adaption is exhausted, surgical intervention is urgent, the prognosis, however, is already limited. To quantify the hemodynamic severity of aortic stenosis, transaortic pressure gradients (dp) measured by Doppler echocardiography or hemodynamically are inappropriate, because dp is significantly dependent on the transaortic flow volume. In severe aortic stenosis, despite constant narrowing of the aortic valve area, the reduced stroke volume results in decreasing transaortic pressure gradients. With aortic valve resistance or transaortic pressure loss (PL)--the quotient of pressure gradient and stroke volume--the hemodynamic severity of aortic stenosis can be described accurately. If PL is known, a decompensated aortic stenosis (PL > 1 mm Hg/ml) may be differentiated from myocardial failure of another etiology and a concomitant left ventricular outflow tract obstruction. With respect to medical therapy, the prevention of bacterial endocarditis and thromboembolic complications is important. Knowing the potential danger of syncopies and ventricular arrhythmias during exercise with increasing severity of aortic stenosis, patients have to be informed about their limited functional capacity. The occurrence of typical symptoms during the natural history of chronic aortic stenosis (e.g. dizziness, syncopes, angina pectoris, arrhythmias) manifestation of ST-T-alterations or silent myocardial ischemias and demonstration of an inadequate myocardial adaptation to the chronic pressure overload in asymptomatic patients are accepted indications for a surgical intervention. If the indication for surgery remains uncertain, stress tests (e.g. radionuclidventriculography) may be performed to demonstrate an exhausted myocardial adaptation. If the PL and the severity of aortic valve/anulus calcification is known, the progression of a chronic aortic stenosis can be estimated. This might be important, if a cardiosurgical intervention has to be performed for other indications and aortic stenosis is co-existent but does not require an intervention at that time. For prognostic reasons myocardial decompensation due to aortic stenosis is an indication for an urgent surgical intervention. Attempts for medical recompensation or bridging strategies (e.g. balloon valvotomy) worsens the prognosis significantly.