Quantitative Radiocardiography in Major Pulmonary Thromboembolism

Cardiac index (CI) and pulmonary blood volume index (PVBI) were measured by quantitative radiocardiographic studies using radioactive 113mindium and a scintillation probe in 37 patients with confirmed major pulmonary thromboembolism. The mean PBVI was 185 ± 11 ml/sq m (SE) and was significantly less than normal (310 ± 5 ml/sq m [SE]; P < 0.001). Six patients with major pulmonary thromboembolism had a PBVI within the normal range (262 to 358 ml/sq m; mean ± 2 SD), and the mean pulmonary vascular occlusion was 21 percent in these patients. Eighteen patients (49 percent) died, and the most significant correlate of mortality was CI, which was depressed (less than 2.7 L/min/sq m) in all but two. Twenty-three serial determinations of pulmonary blood volume (PBV) ranging from 1 to 18 days after the initial study showed a mean increase in PBV of 27 ml/day in ten survivors. Quantitative radiocardiographic studies provide a means of diagnosing major pulmonary thromboembolism by measuring decreases in PBVI; it can assess the magnitude of major pulmonary thromboembolism and can assess CI and, thereby, predict risk of mortality; and it provides a means of following the resolution rate of major pulmonary thromboembolism.