Topical nitroglycerin and lidocaine to dilate the radial artery prior to transradial cardiac catheterization: A randomized, placebo-controlled, double-blind clinical trial: The PRE-DILATE Study

Transradial access (TRA) is being increasingly used for both diagnostic and interventional cardiac procedures. Use of TRA offers many advantages: decreased bleeding, vascular complications, reduced length of hospital stay, and reduced cost. However, the small size of the radial artery limits the size of the equipment that can be used via this approach. We sought to determine whether pre-procedural administration of topical nitroglycerin and lidocaine increases the size of the radial artery. Patients undergoing transradial cardiac catheterization were randomized in a double-blind fashion to a topical combination of nitroglycerin+lidocaine or placebo ointment. The primary endpoint was change in radial artery size. Secondary endpoints included radial artery spasm and radial artery patency. 86 patients were enrolled (43 allocated to treatment group and 43 to placebo group). Patients underwent ultrasound of the radial artery at baseline and before the catheterization. Complications were rare: one hematoma (placebo group) and one radial artery occlusion (placebo group). Baseline demographic and clinical characteristics were similar. The baseline radial artery cross-sectional area (CSA) was similar in both groups (4.95 ± 0.24 mm(2) in placebo group and 5.14 ± 0.34 mm(2) in the treatment group). However, the final CSA decreased to 4.66 ± 0.25 mm(2) in the placebo group and increased to 5.78 ± 0.38 mm(2) in the treatment group (p=0.02), which corresponded to a decrease in CSA by -5.6 ± 2.1% and an increase in CSA by 16.5 ± 4.2% (p