Inversion of the radionuclide regurgitant index in right-sided valvular regurgitation

Abstract

Estimation of left-sided valvular insufficiency has been obtained using the ratio of left- to right-ventricular stroke counts, i.e., the regurgitant index. The present study was designed to evaluate the usefulness of the regurgitant index in identifying patients with isolated right-sided valvular insufficiency. We identified 12 patients with tricuspid or pulmonic regurgitation by at least two of the following criteria: (1) pulsatile liver, (2) positive Carvallo's sign, and (3) pulsatile jugular-venous distension. In 9 of the 12 patients, the right-sided insufficiency was confirmed by catheterization or contrast echocardiography and flow-directed pulsed-echo Doppler. The regurgitant index in patients with right-sided insufficiency was 0.59±0.23. This was significantly different from patients with left-sided insufficiency (3.09±0.8; P<0.001) and from control subjects (1.49±0.32; P<0.001). In 11 of the 12 patients with right-sided regurgitant lesions, the regurgitant index was less than 1.0. The hepatic expansion fraction, a possible correlate of an expansile liver, has previously been found to be both sensitive and specific for the detection of patients with right-sided regurgitation. We calculated the hepatic expansion fraction in 6 patients with tricuspid regurgitation (including 3 with pulsatile livers) and 5 controls using the method of Handler et al.. In the present study, the hepatic expansion fraction in tricuspid-insufficiency patients was 4.3% as compared to 4.1% in normals (P=NS). In summary, this study suggests that the regurgitant index may be a sensitive tool for the diagnosis of right-sided regurgitant lesions, while the hepatic expansion fraction does not appear to be useful for identifying tricuspid insufficiency.