抄録
Left ventricular (LV) afterload increases after mitral valve replacement, thus it would be useful to estimate postoperative LV afterload before surgery. We tested the usefulness of an index, wall stress, obtained from preoperative end-diastolic LV dimensions and diastolic blood pressure which would represent LV afterload after surgery. The data were compared with surgical mortality and morbidity. The wall stress ranged from 98 to 220 kdynes/cm2 and was 202 or higher in 3 patients who died. Five patients had wall stress above 200 kdynes/cm2. Among these, intra-aortic balloon pumping (IABP) was used in 4, and 3 died. Prolonged catecholamine support for >10 days was given to all of the 4 patients, including two who died 14 and 23 days after surgery. Among 38 patients who had wall stress less than 200 kdynes/cm2, none died, IABP was performed in 3 patients, and prolonged catecholamine infusion was required in 5 patients. The incidence of mortality and morbidity were significantly higher in the high stress than in the low stress group (Chi-square analysis). Left ventricular end-diastolic index was larger in the high stress than in the low stress group (p<0.05). The mass/end-diastolic volume ratio was smaller in the high stress group than in the low stress group (P<0.05). In conclusion, this new index, predictive wall stress, is useful in selecting patients who would have high mortality and morbidity.
