Does the Kensey catheter keep a coaxial position inside the arterial lumen? An in-vitro angioscopic study.

Angioscopy was used to evaluate the "self-centering" ability of three Kensey catheters (KC) with different flexibility: one 8Fr "peripheral" and two 5Fr "coronary" (I & II). Angioscopic observations were made inside arteries, 5-18 mm in diameter. There was a good correlation between flexibility and self-centering of the KC [r = 0.83, p less than 0.05]. Increasing the flow rate of rinsing solution from 18 to 60 ml/min prolonged coaxial position from 8.9 +/- 3.3 to 36 +/- 2.2 sec/min of activation [p less than 0.001]. A smaller effect on coaxial position was exerted by increasing cam speed from 5.2 +/- 0.7 to 19.2 +/- 1.6 sec/min (p less than 0.001). In conclusion, angioscopy showed that the KC has a limited ability to maintain a coaxial position inside the arterial lumen and operators cannot rely on its self-centering property.