Differences of intravenous nitroglycerin responses in left ventricular systolic and end-diastolic pressures and coronary artery diameters during long-term treatment with cutaneous nitroglycerin patches.

The differences of intravenous nitroglycerin responses in left ventricular (LV) systolic and end-diastolic pressures and in coronary artery diameters (cross-tolerance) were investigated in patients receiving nitroglycerin patches. During diagnostic cardiac catheterization, graded doses of 50, 100, and 150 mcg of intravenous nitroglycerin were given. Left ventricular systolic and end-diastolic pressures and left coronary arteriograms were obtained during each dose. Twenty patients with coronary artery disease were studied. Before cardiac catheterization, 10 received nitroglycerin patch (patch group), and 10 did not (control group). In the control group, graded intravenous nitroglycerin doses of 50, 100, and 150 mcg caused decrease in LV systolic pressure of 18 +/- 7%, 20 +/- 5%, and 23 +/- 6%, respectively. In the patch group, the same intravenous nitroglycerin doses decreased LV systolic pressure by 12 +/- 6% (p < 0.05), 19 +/- 7% (NS), and 18 +/- 6% (p < 0.05), respectively, (p value: vs. control group). At the same intravenous nitroglycerin doses, LV end-diastolic pressures were decreased by 48 +/- 14%, 52 +/- 17%, and 56 +/- 9%, respectively, in the control group. However, there were no significant differences in LV end-diastolic pressure between the two groups for any of the three intravenous nitroglycerin doses. The same intravenous nitroglycerin doses caused increase in diameter of the left anterior descending coronary artery and circumflex coronary artery in the control group, which was attenuated significantly in the patch group. Tolerance may develop in LV systolic pressure and coronary artery diameters, whereas it may not develop in LV end-diastolic pressure.(ABSTRACT TRUNCATED AT 250 WORDS)