Hemodynamic Consequences of the Injection of Radiopaque Material

TLDR

Injection of radiopaque material into the left heart produces hemodynamic changes, but the mechanism by which hypertonic solutions elicit these effects remains unknown. The study examines how the physiological effects of hypertonic media differ when injected into the right versus the left circulation. Because pressure changes are easily monitored and mirror other hemodynamic responses, injections are delayed until pressures return to baseline, a process that typically takes about 15 minutes. Hypertonic radiopaque material induces a characteristic hemodynamic reaction—left atrial pressure rise, altered pulse contour, increased stroke output, unchanged heart rate, lowered peripheral artery pressure, reduced hematocrit, and a mild transient drop in myocardial contractility—which can be reproduced in experimental animals.

Abstract

The hemodynamic changes resulting from injection of radiopaque material into the left heart in a series of patients undergong cineangiographic studies have been reported. The hypertonicity of radiopaque materials appears to be responsible for much of the observed reaction. The mechanism whereby hypertonic solutions produce the observed physiologic changes remains unknown. Changes observed in patients could be reproduced in experimental animals. The combined experimental and clinical data show that left atrial pressure increases, left atrial pulse contour alters, stroke output increases, heart rate is much unchanged, peripheral artery pressure falls, hematocrit level falls, and myocardial contractile force decreases mildly and transiently. The difference between the physiologic effects of injecting hypertonic media into the right and left sides of the circulation is discussed. Because the pressure changes are easy to monitor and parallel the other features of the hemodynamic reaction, it is good to wait until pressures have returned to the pre-angiographic level before proceeding with the injection of more radiopaque material. This usually requires 15 minutes.