[Differences in loading condition and its effects for valve replacement between chronic aortic and mitral regurgitation].

In order to clarify the differences of left ventricular mechanics between chronic aortic and mitral regurgitation (AR and MR), 23 patients with AR and 17 patients with MR were studied by noninvasive techniques. There were no differences between two types of regurgitation in R/Th, LV dimension, LVEDVI, PWTd, LV mass I and mean blood pressure. However, the peak systolic wall stress (PSWS), ESVI and systolic blood pressure (sBP) of AR were significantly higher than that of MR. One month after valve replacement (VR), in AR all parameters decreased significantly expect increased PWTd. But in MR, blood pressure, LV systolic size and LV mass I were unchanged, although LVDd, LVEDVI, PSWS and R/Th decreased significantly. These results indicates that high PSWS in AR is diminished effectively after AVR by both effects of reduction of LV volume and sBP, although in MR, as a sBP is kept in low level, a drop of PSWS after MVR occurs only due to reduction of volume. Therefore, systolic function after MVR for MR with impaired myocardium may be more destroyed by relatively high afterload as it is difficult to diminish the volume, even if LV function was kept relatively in good condition before operation.