Thrombus formation on guide wires during routine PTCA procedures: a scanning electron microscopic evaluation.

Background: Various coatings are used on catheters and guide wires to improve resistance to surface thrombus formation. However, little is known about the thrombogenicity of 0.014" angioplasty guide wires and the protection offered by these coatings.

Objectives: To evaluate the thrombogenicity of five different guide wires used in coronary angioplasty.

Methods: Five different 0.014" guide wire types were evaluated in 50 consecutive angioplasty procedures. At the end of the procedure, the distal part of the guide wire was cut, put in formalin and prepared for scanning electron microscopic evaluation. The condition of each guide wire was then classified into one of three predefined categories: no thrombus, limited thrombus and significant thrombus formation.

Results: Silicone (n=10, Guidant, USA), phosphorylcholine polymer (n=8, Biocompatibles, Ireland), hydrophilic polymer (n=8, Scimed, USA) and two Teflon-based coatings (n=16, Schneider, USA; n=8, Cordis, USA) were evaluated. On microscopic examination, 48% of guide wires had a significant amount of thrombus, 18% had limited thrombus formation and 34% had no thrombus. The results were very dissimilar among the groups. Significant thrombus was found on 80% of Guidant guide wires, 69% of Schneider guide wires, 38% of Scimed guide wires and 25% of Cordis guide wires, while none was found on Biocompatibles guide wires (P<0.0001).

Conclusions: Significant thrombus formation on angioplasty guide wires was a frequent finding, occurring in 48% of cases. Resistance to thrombus formation was very dissimilar among coatings, with only the Biocompatibles phosphorylcholine-coated guide wires showing no thrombus formation at all. Whether subclinical thromboembolization occurred in some patients is unknown, and the clinical implications of this study remain to be defined.