A method for quantitative detection of tricuspid regurgitation with double injection--single sampling dye-dilution technique.

A method for quantitative detection of tricuspid regurgitation is proposed. In cases without tricuspid insufficiency or intracardiac shunt, 1/slope (ts-fv) of the earpiece dye-dilution curve after injection of dye into the femoreal vein (fv curve) was significantly correlated with that (ts-pa) of the curve after injection into the pulmonary artery (PA curve) within each range of right heart blood volume (rbv) calculated as a product of cardiac output and mean transit time difference between FV curve and PA curve. The relationship among the 3 parameters was expressed as a statistically significant regression equation; log (tsfv) equals 0.9858 log (ts-pa) plus 0.2980 log (RBV) minus 0.6418 (p small than 0.005, sd of predicted ts-fv equals plus or minus 0.591). The assumption was made that tricuspid regurgitation caused prolongation ot ts-fv without any changes in ts-pa or RBV, being based on the concepts of the indicator dispersion and of the path-length distribution. The ratio of tricuspid regurgitation to cardiac output was calculated from (observed ts-fv-predicted ts-fv)/predicted ts-fv, in which predicted ts-fv is the value calculated from ts-pa and RBV using the equation shown above. In 2 patients who manifested clinical tricuspid insufficiency, large amount of tricuspid regurgitant fraction was determined by this method. It is suggested that the present method utilizing double injections--single sampling dye-dilution technique is useful for clinical quantitation of tricuspid regurgitation.