Krause W, Press W R
Schering AG, Berlin, Germany.
Invest Radiol. 1997 May;32(5):249-59. doi: 10.1097/00004424-199705000-00001.
Contrast agents have been reported to influence the blood clotting system to an extent depending mainly on whether the compounds are ionic or nonionic. The objective of the current series of studies was to determine interspecies differences; the effect of variable incubation times; and the effect on thromboplastin times (TPT) of adding heparin to a number of x-ray and magnetic resonance imaging (MRI) contrast agents. In addition, the stability of clots formed in the presence of iopromide was studied. In a final experiment, the effect of the contrast agents on the bleeding time was studied in rats.
Nine x-ray and three MRI contrast agents were used in the study. Thromboplastin times was determined in platelet-poor plasma of humans, rats, rabbits, or dogs using calcium (Ca) thromboplastin from human placenta or rabbit brain and lung tissue and incubation times as long as 4 hours. Bleeding times were determined in rats 5 minutes, 4 hours, 24 hours, and 48 hours after intravenous injection of the contrast agents by making a small incision into the tail of the animal, immersing the tail in saline, and measuring the time period during which small blood streaks were visible.
Nonionic contrast agents (x-ray and MRI) increased the TPT by a factor of 1.5 to 2, whereas ionic compounds prolonged TPT by a factor of > 3. Thromboplastin times increased in the order of dog < rabbit < rat < human 2- to 4-fold. However, the ranking of different contrast agents remained unchanged. Prolongation of bleeding time lasted as long as 24 hours for some contrast agents. Clots formed in the presence of iopromide were unstable and did not absorb the contrast agent.
The animal models used in the current series of studies seem to be valid for predicting the effect of contrast agents on the blood clotting system in humans.
据报道，造影剂对血液凝固系统有一定影响，主要取决于化合物是离子型还是非离子型。本系列研究的目的是确定种间差异；不同孵育时间的影响；以及向多种X射线和磁共振成像（MRI）造影剂中添加肝素对凝血酶原时间（TPT）的影响。此外，还研究了在碘普罗胺存在下形成的血凝块的稳定性。在最后一项实验中，研究了造影剂对大鼠出血时间的影响。
本研究使用了9种X射线造影剂和3种MRI造影剂。使用来自人胎盘或兔脑及肺组织的钙（Ca）凝血活酶，在人、大鼠、兔或犬的乏血小板血浆中测定凝血酶原时间，孵育时间长达4小时。在静脉注射造影剂后5分钟、4小时、24小时和48小时，通过在动物尾巴上做一个小切口，将尾巴浸入盐水中，并测量可见小血痕的时间段，来测定大鼠的出血时间。
非离子型造影剂（X射线和MRI）使TPT增加1.5至2倍，而离子型化合物使TPT延长超过3倍。凝血酶原时间按犬＜兔＜大鼠＜人增加2至4倍。然而，不同造影剂的排名保持不变。某些造影剂导致的出血时间延长可持续长达24小时。在碘普罗胺存在下形成的血凝块不稳定，且不吸收造影剂。
本系列研究中使用的动物模型似乎可有效预测造影剂对人体血液凝固系统的影响。
