Predicting postoperative haemodynamics in valve patients.

Patients with combined valve and myocardial disease often have poor haemodynamic status early postoperatively. This occurs in spite of normalization of the left ventricular work load by technically uncomplicated valve replacement. Therefore an algorithm was developed for predicting postoperative left ventricular performance, based on the Emax concept, (end-systolic wall stress/volume relationship as a load-independent ventricular function parameter). Load changes effected by valve normalization were included in the predictive methodology, with ventricular function assumed unchanged by surgery. The algorithm was tested in 12 valve patients who had less than 10% change in heart rate and left atrial pressure pre- vs postoperatively. Preoperative data were obtained during catheterization with quantitative ventriculography. The predicted data were compared to measured data on postoperative day I. There were non-significant differences between the means of predicted and of measured postoperative left ventricular stroke volume, end-systolic volume, end-systolic stress, stroke work, and aortic pressure. The postoperative myocardial function parameter fell by 3-20% below preoperative values in 8 patients not requiring high-dose catechol support and rose by 3-36% in those requiring support. This pilot study suggests the feasibility of a predictive haemodynamic algorithm in surgical valve disease.