Response of the radial artery to three vasodilatory agents

We examined the response of the radial artery to vasoactive agents (isosorbide dinitrate, ISDN, 1 mg, 3 mg, and 5 mg; verapamil, 1 mg, 3 mg, and 5 mg; and lidocaine, 10 mg, 30 mg, and 50 mg) in 100 consecutive patients admitted for elective coronary angiography. The drug solutions were directly injected into the radial artery from the puncture site. As a result, 5 mg of ISDN increased the diameter of the radial artery by 31% and 28.8% at the proximal and distal sites, respectively. Similarly, 5 mg of verapamil increased it by 9% and 10.8% at the proximal and distal site, respectively. But 10 mg of lidocaine decreased it by -15.6% and -12.1% at the proximal and distal site, respectively. At the doses utilized, ISDN was the most potent vasodilator for the radial artery and lidocaine caused paradoxical vasoconstriction.