Material thrombogenicity in central venous catheterization: a comparison between soft, antebrachial catheters of silicone elastomer and polyurethane.

In order to compare two types of long, soft central venous catheters with the same stiffness, 39 silicone elastomer (SE) and 36 polyurethane (PU) catheters were inserted in 75 patients via basilic or cephalic veins punctured at the cubital fossa. Mean duration of catheterization was 10.5 days. Scanning electron microscopy revealed that the SE catheters to have a more uniform, but somewhat rougher surface topography than the PU catheters. The platelet adhesion in vitro to the SE catheters was four times higher than to the PU catheters. The incidence of clinical thrombophlebitis in the arm veins was 36% with the SE catheters, and 5.5% with the PU catheters (p less than 0.01). No significant differences were found between the SE and PU catheters regarding the number and size of radiologic thrombi in the peripheral and central veins, catheter occlusion rate, and platelet adhesion to the inner side of the catheter tip at withdrawal. Platelet adhesion in vivo correlated with the duration of catheterization in both groups of catheters. Mechanical trauma to the vein endothelium seems to be of vital importance in thrombus formation, but not in the induction of clinical thrombophlebitis.