Radial arterial function following percutaneous cannulation with 18- and 20-gauge catheters.

Radial arterial function was evaluated in 108 patients following 24 hours of percutaneous cannulation with either 18- or 20-gauge cannulas. Arteriography, Doppler ultrasound examination, and Allen's test disclosed an 8 per cent incidence of radial-artery occlusion following cannulation with 20-gauge cannulas, compared with a 34 per cent incidence of occlusion with 18-gauge cannulas (P less than .05). Vessels that occluded were significantly smaller in diameter than were patent vessels (mean 2.00 +/- .09 mm SE vs. 2.22 +/- .05 mm, P less than .05). Occluded vessels also contained significantly greater amounts of thrombotic material (0-3+) just prior to decannulation than those that remained patent (2.42 +/- .13 vs. 1.20 +/- .11,P less than .001). The incidence of arterial occlusion increases linearly as the ratio of cannula outer diameter to vessel-lumen diameter increases.