ALTERATIONS IN FIBRIN DETECTED IN CORONARY SINUS BLOOD AFTER HEPARIN AND CORONARY ANGIOGRAPHY WITH A NONIONIC CONTRAST AGENT (IOHEXOL)

Although heparin and some radiographic contrast agents inhibit coagula tion, thrombi can still form in their presence. The chemical environme nt in which a thrombus forms affects fibrin structure that may alter t he ability of the thrombus to be lysed. Therefore, we assessed changes in fibrin structure in 13 patients referred for coronary angiography. Blood was obtained from the femoral vein, femoral artery, ascending a orta, left main coronary artery (LMCA), and coronary sinus (CS) before , during, and after coronary angiography was performed with iohexol. T he number of fibrin monomers per fiber cross section was determined by turbidity measurements of fibrin gels formed from plasma samples. At baseline there was no difference in the number of fibrin monomers per fiber cross section in plasma gels generated from the different sampli ng sites. After iohexol administration, there was a significant decrea se in the number of fibrin monomers per fiber cross section at the sam pling sites ranging from -13% to -25% compared with the respective bas eline values with the largest change in the LMCA CS (51 +/- 16 to 38 /- 15, p <0.025). transcardiac (LM - CS valve) changes in the number o f fibrin monomers per fiber cross section were dependent on the timing of the sample collection in the CS. In 7 patients, the CS sample was collected approximately 2 minutes after injection of contrast material and there was no transcardiac difference. When the CS sample was obta ined during contrast injection (n = 6) a large transcardiac change occ urred (44 +/- 10 to 32 +/- 14, p = 0.01), These data show transient ch anges in fibrin structure during coronary angiography with iohexol. Th e thinner fibers formed in the presence of iohexol were more resistant to fibrinolysis. (C) 1998 by Excerpta Medico, Inc.