Hemodynamic Effects of Angiocardiography

Hemodynamic alterations following angiocardiography were studied during 136 injections of sodium iothalamate in 80 adults. The average dose was 0.5 ml/kg. Systemic blood pressure uniformly fell, beginning 13 sec after left heart injection and returning to the control level after 60 sec. The average maximum decrease was 34 mm Hg systolic (25%). Pulmonary arterial, left atrial and left ventricular end-diastolic pressures characteristically rose moderately. Cardiac output (indocyanine green) increased consistently, the average increment being 1.32 L/min (32%). There was a marked temporary decrease in systemic vascular resistance. Serum osmolarity was sharply clevated 10 sec after injection, then gradually declined. Plasma volume (radio-iodinated serum albumin) increased in every patient, the average increment being 223 ml, a 4% rise. These responses seem primarily related to marked hypertonicity of the contrast material. Underlying mechanisms include movement of water into the vascular space with an increased blood volume, a direct vasodilator effect of the hypertonic material and a neurogenic response, the nature of which is not yet clear. Appreciation of these responses may allow anticipation of adverse reactions in certain patients and indicates the need for caution in interpreting physiologic data obtained with angiography.