In the present study, the torsional moments of 8 different types of ca
theter having two different calibres (n = 5 in each case) were investi
gated. The catheters were made of linear polyurethane (Cordis, Netherl
ands). The transmitted torsional moments of the 5.2 Fr. catheters posi
tioned in a straight line were 1.48 +/- 0.09 Nem (VK = 6 %), positione
d 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 behaviou
r in particular of the 5 Fr. catheters with a variation coefficient of
the torsional moments of 6 % - is due mainly to the accurate manufact
ure of the catheters, and the material chosen. The study is a first st
ep towards achieving systematic quality control of the materials used
for diagnosis and therapy.