Effects of Glyceryl Trinitrate on Blood Pressure and Arterial Compliance

Abstract

Glyceryl trinitrate (GTN) mainly reduces systolic blood pressure (SBP) rather than diastolic blood pressure (DBP) in acute conditions. To examine the efficacy of GTN as an antihypertensive agent in patients with isolated systolic hypertension (ISH), the authors examined the effects of GTN on BP and arterial compliance (AC) in patients who underwent cardiac catheterization. Seventy patients (with old myocardial infarction, 36; angina pectoris, 25; chest pain syndrome, 9) who underwent cardiac catheterization because of chest pain were included in this study. They were aged between thirty-seven and seventy-four (mean sixty-one) years. According to the levels of BP at cardiac catheterization, the authors selected two subgroups: the normotensive group (NT group, n = 18) and the isolated systolic hypertensive group (ISH group, n = 20) from all sub jects. The authors measured BP before and after (three minutes) sublingual administration of GTN (0.3 mg) at the cardiac catheterization. AC was assessed by means of diastolic pressure decay. The change of BP was estimated by the differences between values before and at three minutes after GTN. After ad ministration of GTN, SBP was decreased significantly from 157 ± 25 to 142 ± 23 mmHg (P < 0.01), while DBP did not change (83 ± 13 vs 84 ± 15 mmHg). The change in SBP was positively correlated with the pretreatment SBP and nega tively correlated with AC (r = 0.51, P < 0.001; r = 0.39, P < 0.001, respectively). AC was significantly lower in the ISH group than in the NT group (P < 0.01). The change in SBP after GTN was greater in the ISH group than in the NT group (P < 0.01). The change in DBP was not correlated with the pretreatment DBP and AC. These results suggest that GTN is effective in patients with a high SBP and a low AC, indicating that GTN provides a desirable antihypertensive agent for ISH in the elderly.