[The role of radionuclide ventriculograms in determining the indications for valve replacement in chronic aortic valve insufficiency].

Timing of aortic valve replacement (AVR) in chronic aortic regurgitation (AR) remains a difficult problem in clinical practice. Radionuclide ventriculography (RNV) yields information on the extent of valvular regurgitation, the enlargement and the systolic function of the left ventricle. A "well-timed" AVR is defined by 1) postoperative improvement of clinical symptoms, decrease in left ventricular end-diastolic volume (EDV) and normalization of ejection fraction (EF) as well as by 2) greater improvement under surgical therapy as compared to conservative management. In "too early" AVR the latter condition is not fulfilled, while in "too late" AVR the first condition is not accomplished. In this study 54 patients with chronic aortic incompetence were evaluated by RNV to see whether these three groups ("too early", "well timed", "too late" AVR, resp.) can be separated by the relation between EDV and regurgitant volume (RV), the level of the EDV and the clinical status. The examination was based on pre- and postoperative RNV studies as well as on follow-up studies. A good postoperative result can be expected in cases with a preoperative EDV/RV-ratio similar to that observed in 30 patients with AR in whom AVR was not indicated. In contrast, in the majority of those cases with an EDV/RV-ratio exceeding this normal range the postoperative outcome will be unsatisfactory. If the EDV/RV-ratio is normal, AVR should be performed in cases with an EDV exceeding 400 ml, while in cases with an EDV between 300-400 ml AVR is only indicated in the presence of additional symptoms (NYHA greater than or equal to II).(ABSTRACT TRUNCATED AT 250 WORDS)