COMPARISON OF THE ANTITHROMBOGENIC POTENT IAL OF 2 LOW-OSMOLALITY IODINE CONTRAST-MEDIA DURING PERCUTANEOUS TRANSLUMINAL CORONARY ANGIOPLASTY BY SCANNING ELECTRONIC MICROSCOPY

The antithrombogenic potentials of two low osmolality iodine contrast media, ioxaglate (Iox), an ionic product, and iopamidol (Iop), a non-i onic product, were compared in a multicentre, randomised, double-blind study in 64 patients undergoing percutaneous transluminal coronary an gioplasty (PTCA) by scanning electron microscopy for the presence of t hrombotic material on the guiding catheter (GC) and guide wires (GW). The procedure was strictly standardised: stable angina, type A coronar y lesions; aspirin administration (at least 300 mg the day before and on the day of angioplasty); heparinisation (10000 IU at the beginning of the procedure); same GCs (Marathon Baxter 8F). same GWs (Veriflex U SCI 0.014). The tips of the catheters and guide wires were scanned by an electronic microscope in a double-blind protocol. The scores for th e number of erythrocytes (RBCs), platelets (PLs) and constitued thromb i (THi) were : thickness scored from 0 to 3, the % surface covered and an index of volume combining these two parameters. The clinical and a ngiographic characteristics of the 2 groups were strictly comparable. The time that the GCs and GWs were in the circulation were 30.0 +/- 2. 3 vs 32.6 +/- 3.0 minutes for the former, and 18.6 +/- 1.8 vs 17.1 +/- 1.4 minutes for the later in the Iox and Iop groups. respectively (NS ). An angiographic filling defect was not observed in any of the patie nts in the lox group and in 4 patients (13 %) in the lop group (NS). T he number of thrombotic elements observed on the GCs (RBCs, PLs, THi) was negligeable in both groups. On the other hand, a difference was ob served on the GWs. It was significant with respect to the platelets : % surface covered 24.1 +/- 5.7 % in the Iox group vs 52.3 +/- 7.0 % in the lop group (p = 0.004); distribution with respect to thickness (p = 0.04) and volume index 65.2 +/- 16.3 vs 145.2 +/- 20.2 (p = 0.005). The number of RBCs and THi on the GWs assessed by these 3 parameters w as lower in the lox group but the difference was not statistically sig nificant. This study undertaken in a small number of low risk patients under strickly standardised conditions, confirms, in vivo, that of th e low osmolality contrast media, the antithrombogenic effect is greate r with the ionic than with the non-ionic. This raises the question of the potential role and choice of contrast media for PTCA, especially i n complex procedures and in patients at high risk of acute closure.