Control of catheters in coronary angiography--resistance to torsion in the aortic arch
Schröder, J.
Zeitschrift für Kardiologie 81(8): 449-452
1992
ISSN/ISBN: 0300-5860 PMID: 1413954 Document Number: 402085
A curved catheter, unlike a straight catheter, cannot be rotated around its longitudinal axis without resistance. In a curved catheter section, the torsion causes internal deformation of the material which consumes energy and which is associated with resistance to rotation. This resistance can be measured in terms of a moment of torsion (Nm); it greatly differs in magnitude depending on the cross-section of the catheter and on the catheter material. This resistance to rotation must always be reckoned with in transfemoral coronary angiography, as a consequence of the semicircular curvature of the catheter. The controllability of the catheter therefore does not depend solely on its (likewise measurable) torsional stability, but rather on the ratio between the torsional stability and resistance to rotation in the aortic arch. In the 20 catheter types of caliber 7F, 6F, and 5.2F investigated, the corresponding measurement results were the most favorable for 6F braided nylon catheters.