Analytical assessment of Broviac catheter occlusion

Eight of 92 consecutive silastic central venous catheters used for home parenteral nutrition occluded. Six of the eight had patency restored by the instillation of urokinase or streptokinase into the catheter. The thrombus in one of the two catheters that was not reopened with thrombolytic agents was studied in detail by electron microscopy, x-ray dispersive analysis, solubility in isopropyl alcohol-diethyl ether (1:1, v:v), and thin-layer chromatography of extracted lipids. Electron microscopy found the clot to be an amorphous mass without features to suggest crystalline properties. The x-ray dispersive analysis showed that the only elements which were significantly increased were chloride and silicon and the silicon detected was likely from the underlying catheter. Treatment with isopropyl alcohol-diethyl ether left an insoluble, flaky residue that resembled protein from a thrombus. Thin-layer chromatography detected a lipid profile suggestive of circulating endogenous fat instead of the fat that was infused through the catheter.