Assessment of explanted PTCA balloons

The data presented here are part of a on-going study to define the surface characteristics and properties of explanted PTCA catheters in a further effort to address some of the ramifications of the re-use issue. PTCA balloon catheter were examined after angioplasty in one hundred and sixty-eight patients (n = 168). This series included six balloon types from three manufacturers. The fresh fixed and dehydrated balloons were examined at first with light microscopy and then in a scanning electron microscope. X-ray semiquantitative microanalysis and FT-IR-ATR analysis were also performed on the balloons. Because most blood proteins are water soluble, we examined unfixed balloons with a protein silver staining kit for detection of adhered proteins described by Heukeshoven. A further method for protein detection is the Lowry-analysis. With this method water insoluble proteins can be observed. Our study has shown convincingly that all deployed angioplasty catheters were coated with adherent protein layers. Plaque particles were found embedded in the surfaces of most of the balloons examined. Fissuring and micro tearing of balloon surfaces was noted. FT-IR-ATR analyses of the blood contacted balloon surfaces did not show any peaks indicative of proteins on the balloon surface. The silver staining method also did not show any evidence of protein adsorption on the balloons. On the other hand, the Lowry-analysis yielded clear evidence that water insoluble proteins were adherent to the balloon surfaces. The average measured protein concentration was 17 microg/ml.