Effect of cutaneous nitroglycerin patches on coronary artery diameter: issues concerning development of tolerance

The coronary dilative and systemic responses to graded doses of intracoronary nitroglycerin were studied in 53 patients undergoing diagnostic coronary arteriography, 43 of whom had received a cutaneous nitroglycerin patch. During coronary arteriography, graded doses of 50, 100 and 200 micrograms of intracoronary nitroglycerin were given 5 min apart. An arteriogram and hemodynamic measurements were obtained after each dose. In the control group (n = 10) cumulative intracoronary nitroglycerin doses of 50, 150 and 350 micrograms caused an increase in coronary diameter in the left anterior descending artery of 20 +/- 4%, 21 +/- 3% and 22 +/- 7%, respectively, and in the circumflex artery of 18 +/- 6%, 23 +/- 8% and 18 +/- 5% (p less than 0.01 versus values in untreated group). In Group 1 (15 patients given a 5 mg/24 h nitroglycerin patch 2 to 12 h before coronary arteriography), the same intracoronary nitroglycerin doses increased the left anterior descending artery diameter by 6 +/- 2%, 7 +/- 2% and 7 +/- 2%, respectively, and the circumflex artery diameter by 3 +/- 2%, 3 +/- 2% and 1 +/- 3%. All values were statistically different from control (p less than 0.05). An even more pronounced blunting (p less than 0.01) of the coronary dilative response was observed in Group 2 (14 patients given a 15 mg/24 h nitroglycerin patch 2 to 12 h before arteriography).(ABSTRACT TRUNCATED AT 250 WORDS)