[Torsion stability of coronary catheters]

In the present study, the torsional moments of 8 different types of catheter having two different calibres (n = 5 in each case) were investigated. The catheters were made of linear polyurethane (Cordis, Netherlands). The transmitted torsional moments of the 5.2 Fr. catheters positioned in a straight line were 1.48 +/- 0.09 Ncm (VK = 6%), positioned in a 90 degree curve 1.39 +/- 0.11 Ncm (VK = 8%). The corresponding figures for the 6 Fr. catheters were 2.43 +/- 0.20 Ncm (VK = 8%) and 2.26 +/- 0.20 Ncm (VK = 9%). The highly stable transmission behaviour in particular of the 5 Fr. catheters--with a variation coefficient of the torsional moments of 6%--is due mainly to the accurate manufacture of the catheters, and the material chosen. The study is a first step towards achieving systematic quality control of the materials used for diagnosis and therapy.