Plasma Clearance of Indocyanine Green Following Experimental Myocardial Infarction in Dogs

Abstract

Abnormalities of liver function have previously been reported in patients with severe heart failure (1) and also in patients with complicated acute myocardial infarction ( 2 ) . The following investigation was carried out in dogs with acute myocardial infarction to determine whether disturbances of liver function can be detected, and related to the relatively mild impairment of circulatory function which characterizes this experimental preparation.Methods. Mongrel dogs weighing from 16-24 kg were anesthetized with 30 mg/kg of pentobarbital, and subjected to an openchested staged ligation of the left anterior descending coronary artery (3 ) . Twelve animals survived this procedure and the period of sustained ventricular arrhythmia which invariably occurred over the next 2 days. On the third or fourth day following ligation, a t a time when arrhythmias had ceased, the animals were premedicated with 1.5 mg/kg of morphine sulfate, then anesthetized with a mixture containing 200 rng of urethane, 30 mg of pentobarbital, and 50 mg of allobarbital per ml. The animals were ventilated with a Harvard respiratory pump. Animals were instrumented for hemodynamic measurements as described in detail elsewhere (4). A second group of 7 animals was subjected to a sham operation, and otherwise treated in an identical fashion; these served as controls. Arterial oxygen saturation exceeded 90% in every animal. Indocyanine green dye (12.5 mg) was injected as a bolus into the right atrium, and the arterial concentration was recorded continuously from a fiberoptic catheter placed * Supported by grants-in-aid from the National Institutes of Health (HE-07776-04, 5 TI-HE-5242 and PO-1-HE-11306-01) ; the John A. Hartford Foundation; and the Fund for Research and Teaching, Harvard School of Public Health, Department of Nutrition.in the arch of the aorta (5). Total blood volume was calculated by extrapolating the dye concentration curve to the time of injection. This was done from a replotted log dye concentration-time curve, utilizing only the exponential portion of the curve after mixing was completed. Plasma volume was calculated from duplicate microcrit determinations, without correction for trapped plasma. The halftime ( t 1 / 2 ) of disappearance of indocyanine green was also measured from the semilogarithmic plot of the fiberoptic tracing, and plasma clearance was calculated as described by Rowel1 et al. ( 6 ) , from the relationship: plasma clearance = (0.693/t1/2) (plasma volume).In an attempt to clarify the effect of acute changes in hemodynamics on removal of indocyanine green by the liver, an additional eight normal dogs were studied during selective alteration of aortic and hepatic venous pressure. This was accomplished by inflating a balloon catheter positioned fluoroscopically either in the thoracic aorta, above the celiac axis, or in the inferior vena cava, just above the level of the diaphragm. Pressures were measured from catheters positioned below the level of obstruction, in the abdominal aorta and inferior vena cava a t the...

The Indocyanine Green Extraction Test of Liver Function in Pulmonary Disease

“…Leevy et al, (1962) noted that hypoxia induced by breathing 10% oxygen did not influence the hepatic extraction of indocyanine green. Extraction has been shown to be abnormal in experimental cardiac infarction (Hood et al, 1968) and in myocardial infarction in man (Cobb and Saunders, 1970) the abnormality probably relating to reduced liver blood flow, other liver function tests being normal.…”

The use of computer-assisted experiments in the canine to support the development of a mathematical model for the hepatic removal of indocyanine green dye under normal and reduced hepatic blood flow conditions

“…The rate of ICG uptake can also be affected by the presence of cardiovascular pathology. Hood et al (1968) reported a 41% decrease from normal in the plasma clearance of ICG in dogs three to four days following surgical ligation of the left coronary artery. It was hypothesized that the more severe cardiac impairment immediately following myocardial in farction may be the cause of sustaining injury to the liver.…”