NITRATE-INDUCED CORONARY VASODILATATION - DIFFERENTIAL-EFFECTS OF SUBLINGUAL APPLICATION BY CAPSULE OR SPRAY

Background-Sublingual nitroglycerin (glyceryltrinitrate, GTN) capsules or isosorbide dinitrate (ISDN) spray are routinely used to treat angi nal attacks and to vasodilate maximally the epicardial coronary arteri es during coronary angiography. Objective-To compare the coronary vaso dilatory effects of GTN capsules and ISDN spray with those induced by intracoronary GTN using quantitative coronary angiography. Design-96 p atients (79 men and 17 women; median age 59 years) were randomised to four groups to receive either a sublingual capsule containing 0.8 mg G TN or two puffs of spray delivering 0.8 mg ISDN, followed or preceded by an intracoronary bolus of 0.2 mg GTN used as reference for maximal vasodilatation. Results-There was a significant increase in the mean d iameter of coronary arteries in angiographically normal segments in pa tients who received either intracoronary GTN (groups 1 and 2) or ISDN spray (group 4) as a first application (group 1, 0.46 mm, +17%, (basel ine vessel diameter 100%), p < 0.001; group 2, 0.45 mm, +13%, p < 0.00 1; group 4, 0.47 mm, +13%, p < 0.05). Patients who received a sublingu al GTN capsule as the first application mode (group 3) had no signific ant change in epicardial vessel diameter (0.10 mm, +5%, p = 0.3). Conc lusions-Sublingual ISDN spray may be more efficacious than sublingual GTN capsules in certain patients with anginal attacks. ISDN spray shou ld be preferred over capsules in coronary angiographic procedures.