Circulation, Vol 74, 1416-1423, Copyright © 1986 by American Heart Association
HZ Friedman, SF DeBoe, MJ McGillem and GB Mancini
Radiographic techniques used to quantify coronary blood flow all require
bolus injection of contrast material, which markedly alters the flow being
measured. Newer nonionic contrast agents have been shown to have fewer
adverse hemodynamic, inotropic, and rheologic effects compared with ionic
media and it has been suggested that they might not substantially affect
coronary blood flow. Six dogs were instrumented with electromagnetic flow
probes and subendocardial ultrasonic crystals. Intracoronary injections of
iohexol (300 mg/ml iodine) were administered to establish a relationship
between the dose and rate of contrast injection and the effect on flow and
regional myocardial function. Two and 4 ml volumes of iohexol were injected
at 3 ml/sec; 4 ml volumes were administered at 1 and 4 ml/sec. The 2 and 4
ml volumes decreased coronary flow by a mean of 31% (p less than .01) and
77% (p less than .001). The 4 ml injection at 1 and 4 ml/sec 77% (p less
than .001) and 69% (p less than .001). The magnitude of the fall in flow
was directly related to the dose, and the rate at which the flow nadir was
attained was directly related to the rate of injection. Decrements in
fractional shortening were temporally delayed by several beats compared
with the flow changes and showed mean decrements of 19% to 29%. The effects
on regional myocardial function were independent of contrast volume.
However, the degree of dysfunction was more profound with slower infusion
rates, suggesting that prolongation of contrast-induced ischemia was a
major modulating factor.(ABSTRACT TRUNCATED AT 250 WORDS)
ARTICLES
The immediate effects of iohexol on coronary blood flow and myocardial function in vivo
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