Related Experiment Videos
Differences in ischemic threshold and nitrate efficacy between normotensive and hypertensive patients with stable
Insights
Hypertension diminishes the effectiveness of nitrate antianginal therapy in patients with stable angina. Higher oral nitrate doses may be needed for hypertensive individuals to achieve similar benefits as normotensive patients.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Hypertension management is crucial for patients with ischemic heart disease.
- The efficacy of antianginal nitrate therapy in hypertensive patients with stable angina remains unclear.
Purpose of the Study:
- To evaluate the impact of hypertension on nitrate efficacy in patients with stable angina pectoris.
- To assess how hypertension affects the ischemic threshold and time to angina during nitrate treatment.
Main Methods:
- A double-blind, parallel-group study involving 141 patients with stable angina pectoris.
- Patients received varying doses of isosorbide-5-mononitrate or placebo for 21 days.
- Comparison of nitrate effects on anginal pain and ischemic threshold between hypertensive and normotensive groups.
Main Results:
- The antianginal effect of isosorbide-5-mononitrate was significantly reduced in hypertensive patients.
- Time to moderate anginal pain was shorter in hypertensive individuals receiving 10 mg and 20 mg doses.
- Impaired vasodilatory response, possibly due to nitric oxide biotransformation issues, is suggested in hypertensives.
Conclusions:
- Oral nitrate therapy provides less antianginal benefit in hypertensive patients compared to normotensive patients.
- Consideration of dose adjustment or higher doses of oral nitrates is recommended for hypertensive patients with stable angina.
Abstract:
The coexistence of ischemic heart disease with hypertension makes antihypertensive therapy essential, since relief of hypertension may ameliorate the coronary disease. On the other hand, the effect of antianginal nitrate therapy in patients with stable angina pectoris and systemic arterial hypertension is not fully understood. This study assessed the effects of hypertension on the ischemic threshold and the time to moderate angina, measured as parameters of nitrate efficacy. In this double-blind, parallel-group study, 141 patients with stable angina pectoris were randomly assigned to receive 5 mg, 10 mg or 20 mg isosorbide-5-mononitrate or matching placebo bid for 21 days. Ninety-three normotensive and 48 hypertensive patients were compared with regard to the time to moderate anginal pain and the ischemic threshold before and after nitrate treatment on the first day of the study. The acute nitrate effect 2 h after drug administration was substantially attenuated in hypertensives at both 10 and 20 mg of isosorbide-5-mononitrate, with the time to moderate anginal pain being significantly shortened. Impaired vasodilatator response of the arterial vasculature to organic nitrates, probably due to impaired biotransformation of organic nitrates to nitric oxide in hypertensive patients, is suggested as a possible mechanism for the diminished nitrate effect. Thus, oral nitrate therapy does not have the same beneficial antianginal effect in hypertensive patients as it does in normotensives. Dose adjustment based on the pretreatment blood pressure, and the administration of higher doses of oral nitrates should therefore be considered in hypertensive patients suffering from stable angina pectoris.