Mitral annulus and valves form the mitral orifice area with the size between 4.0-6.0 cm2. Every area which is smaller than this, represents mitral stenosis. As a consequence of mitral stenosis hemodynamic gradients occur over the mitral orifice with circulation disturbances below and above the stenotic mitral valve. The size of transmitral gradient is important in the evaluation of functional or/and structural changes in the blood vessels of pulmonary circulation. This investigation included 40 patients with mitral stenosis (or accompanying minimal mitral regurgitation). All patients underwent echocardiographic examination: area of the mitral orifice was determined and hemodynamic procedure with the left and right heart catheterization was performed. The following hemodynamic parameters were measured: mean capillary wedge pressure, left ventricular filling pressure, left ventricular mean diastolic pressure, mean pulmonary artery pressure. According to these parameters resistance in the pulmonary circulation was measured. The size of the mitral orifice was determined according to oximetry blood analyses and hemodynamic parameters. All patients were divided into 4 groups: minimal (2.5-4.0 cm2), mild (1.5-2.5 cm2), moderate (1.0-1.5 cm2) and severe mitral stenosis (1.0 cm2). The comparison of echocardiographic and hemodynamic parameters revealed a high and positive correlation between the area of mitral orifice. There was also a negative and moderate correlation between the values of stenotic mitral orifice area and total pulmonary resistance, i.e. in all patients with severe mitral stenosis there was an increased pulmonary arteriolar resistance.
Conclusion: Noninvasive echocardiographic method is valid in the evaluation of stenotic mitral valve area. In the evaluation of hemodynamic parameters in the pulmonary circulation the index of arteriolar pulmonary systemic vascular resistance is very important. In all patients with the area of stenotic mitral orifice 1.0 cm2, there are functional or pathomorphologic changes in the pulmonary circulation of the blood vessel wall.