Comparative hemodynamic effects of placebo and oral isosorbide dinitrate in patients with significant coronary artery disease

Differential hemodynamic effects of beta-adrenoceptor blockers, Ca antagonists and combined alpha-beta-receptor blockade in ischemic heart disease

The hemodynamic responses to 3 different therapeutical regimens: beta-adrenoceptor blockade, calcium inflow inhibition and combined alpha-beta-blockade were evaluated in 3 matched randomized groups of patients with ischemic heart disease and typical exercise-induced angina. The groups consisted of 22, 16 and 15 men, mean age 55-59 years. They were studied at rest and during ischemia-inducing exercise, before and after single oral doses of 100 mg metoprolol, 10 mg nifedipine and 200 mg labetalol. Pressures in the brachial artery and the pulmonary circulation were recorded by means of percutaneously introduced catheters. Cardiac output was determined according to the Fick principle. Metoprolol reduced mean arterial pressures, heart rate and cardiac output. Systemic vascular resistance and left ventricular filling pressure increased. Nifedipine resulted under all conditions in a distinct reduction of systemic vascular resistance and arterial pressures and a slight increase in heart rate and cardiac output. Left ventricular filling pressure was significantly lowered, the more the higher the initial level. The effect of labetalol was similar to that of nifedipine; however, cardiac output was unchanged and heart rate was slightly reduced. Left ventricular filling pressure was significantly lower. It is apparent that suppression of adrenergic stimulation by beta-receptor blockade alone may have adverse hemodynamic effects in ischemic heart disease and prompt further functional deterioration. Conversely, both calcium and combined alpha-beta-receptor blockade tend to improve left ventricular function by lowering both left ventricular preload and total systemic vascular resistance. The results strongly suggest that in patients in whom beta-receptor blockers appear indicated, their adverse hemodynamic effects can be offset by concomitant alpha1-receptor blockade or vasodilation without losing symptomatic efficacy. Combined alpha-beta-receptor blockade has the advantage over calcium antagonists alone to prevent any increase in adrenergic activity and related hyperkinetic response.

Double-blind randomised crossover trial comparing isosorbide dinitrate cream and oral sustained-release tablets in patients with angina pectoris

Percutaneous isosorbide dinitrate cream and sustained-release tablets were compared in a double-blind randomised crossover trial in 28 patients with coronary artery disease and chronic stable angina pectoris. Twenty-two patients completed the trial. Both preparations significantly increased the mean exercise time to the onset of angina (P less than 0.001) and to termination of exercise (P less than 0.001) compared to the pre-treatment period. There were no significant differences between the cream and tablets with respect to frequency of anginal attacks, glyceryl trinitrate consumption, heart rate and ST segment depression at the onset of angina, ST segment depression at maximal exercise and the double product of heart rate and systolic blood pressure at maximal exercise. Equal numbers of patients expressed preference for cream and tablets. We conclude that in this group of patients isosorbide dinitrate sustained-release tablets have no clinical advantage over isosorbide dinitrate cream which, may, therefore, be of particular value for those patients with angina pectoris who dislike taking tablets or who prefer this form of nitrate preparation.

Haemodynamics and plasma concentrations following sublingual GTN and intravenous, or inhaled, isosorbide dinitrate

We measured plasma nitrate levels and haemodynamics following sublingual glyceryl trinitrate (GTN) (0.5 mg), or isosorbide dinitrate (ISDN) administered intravenously (0.5 mg) or by inhalation (1.25 mg) in 23 patients undergoing cardiac catheterisation for investigation of chest pain. Peak levels were detected at 90 s and 5 min following intravenous and inhaled ISDN respectively and at 3 min following sublingual GTN. Intravenous and inhaled ISDN produced similar plasma levels at 30 s and both were significantly greater than following sublingual GTN. Plasma levels were maintained for longer following inhaled ISDN than intravenous ISDN or sublingual GTN. Haemodynamic responses were qualitatively similar following each treatment; reduction in pulmonary vascular resistance and pressure and left ventricular end diastolic pressure occurred in each group. Heart rate, cardiac output and LV dP/dt.P-1 remained unchanged. Maximal haemodynamic responses were greater following ISDN than GTN, with little difference between the two preparations of ISDN. Haemodynamic responses were more sustained following inhaled ISDN than following sublingual GTN or intravenous ISDN, the latter two being similar in this respect. These findings suggest that inhaled ISDN may provide more rapid and sustained relief from angina than sublingual GTN.

Hemodynamic effects of high-dose sustained-action oral isosorbide dinitrate in stable angina

Hemodynamic effects of sustained-action oral isosorbide dinitrate (40 or 80 mg) were studied in 10 patients with stable angina for a period of 16 hours. Control hemodynamic parameters monitored for eight hours prior to the administration of isosorbide dinitrate showed no significant change. However significant reduction in mean arterial pressure, cardiac index, pulmonary artery wedge pressure, mean pulmonary artery pressure, double product (systolic pressure multiplied by heart rate), stroke volume index, and stroke work index occurred in the first two hours and persisted for 12 hours following the administration of isosorbide dinitrate. Heart rate did not change significantly for 12 hours. It can be concluded that the hemodynamic effects of sustained-action oral isosorbide dinitrate occur in the first two hours and last up to 12 hours. The predominant hemodynamic effect appears to be on the myocardial preload. The antianginal effect of the drug could be attributed to the reduction of myocardial oxygen demand reflected by a decrease in the double product and stroke work. The duration of the hemodynamic changes observed in this study indicates that high-dose oral isosorbide dinitrate could be administered conveniently two or three times daily.

A new oral slow release form of isosorbide dinitrate. Effect on the hemodynamics and exercise capacity of patients with angina

To assess the bioavailability of a new oral and slow release form of isosorbide dinitrate (ISDN-SR), we evaluated 12 patients with confirmed coronary artery disease, chronic stable angina pectoris and abnormal maximal exercise tests (angina-limited and associated with greater than or equal to 0.1 mV ST displacement). Each patient was known to have an increased exercise time after 0.4 mg of sublingual nitroglycerin. Patient responses to exercise on the treadmill at two, four, six, and eight hours after the double-blind administration of 40 mg of ISDN-SR were compared to an identical placebo. It is concluded that 40 mg of this slow release form of isosorbide dinitrate is bioavailable for at least eight hours as demonstrated by significantly improved exercise capacity of the majority (64 percent) of angina patients in this study, each of whom demonstrated anginal limitation to exercise and favorable responses to 0.4 mg of sublingual nitroglycerin.

Hemodynamic effects of felodipine at rest and during exercise in exertional angina pectoris

To examine the antianginal effects of felodipine, a new calcium antagonist, 8 patients with coronary artery disease and exertional angina pectoris were studied. Hemodynamic measurements were made at rest, during submaximal exercise and during angina-limited exercise before and 30 minutes after oral administration of 0.1 mg/kg of felodipine. Angina pectoris was always prevented after the drug was given and the exercise intensity was increased until recurrence of angina (5 patients) or exhaustion (3 patients). Hemodynamic data were also recorded at this higher exercise capacity. At rest and during submaximal exercise, felodipine increased heart rate and decreased arterial blood pressure and systemic vascular resistance. The prevention of angina pectoris was accompanied by lower mean pulmonary capillary wedge pressure, systemic vascular resistance and ST-segment depression; the pressure-rate product was unchanged. The 20% greater exercise capacity after felodipine was attended by a 20% increase in maximal cardiac output, a 17% increase in maximal heart rate and a 13% increase in maximal pressure-rate product; the maximal arterial blood pressure and ST-segment abnormalities were unchanged and the systemic vascular resistance was lower. The relation between ST-segment depression and the pressure-rate product during exercise was favorably influenced by felodipine. Thus, felodipine is an active antianginal drug; its major mechanism of action is to lower the systemic vascular resistance. The data also suggest that it improves coronary blood flow during exercise.

Oral isosorbide dinitrate in angina pectoris: comparison of duration of action an dose-response relation during acute and sustained therapy

The effects of different oral doses of isosorbide dinitrate administered acutely and four times daily during sustained therapy were studied in 12 patients with angina pectoris. After administration of 30, 60 and 120 mg of isosorbide dinitrate, the average plasma concentrations were higher and the area under the plasma concentration time curve was greater during sustained than during acute therapy (p less than 0.01). Reduction in standing systolic blood pressure was greater during acute than during sustained therapy (p less than 0.001). This reduction in systolic blood pressure was dose-related and persisted for 8 hours during acute therapy, but was not dose-related and was demonstrable for only 4 hours during sustained therapy. Compared with placebo therapy, exercise duration to the onset of angina and to the development of moderate angina increased significantly after each dose of isosorbide dinitrate for 8 hours during acute therapy but for only 2 hours during sustained therapy. During acute therapy, administration of a single dose of 15 or 30 mg of isosorbide dinitrate produced similar improvement in exercise tolerance as did a dose of 60 or 120 mg. During sustained therapy (15 mg four times daily), exercise tolerance increased to the same magnitude as with doses of 30, 60 or 120 mg four times daily. In most patients, near maximal improvement in exercise tolerance occurred after a dose of 15 or 30 mg four times daily. It is concluded that during sustained therapy with isosorbide dinitrate, partial tolerance to the antianginal and circulatory effects develops rapidly.

Hemodynamic effects of molsidomine at rest and during submaximal and maximal exercise in patients with coronary artery disease limited by exertional angina pectoris

To analyze the mechanisms of action of molsidomine, a new antianginal drug, 10 patients with coronary artery disease and exertional angina pectoris were studied. Hemodynamic measurements were made at rest, during submaximal exercise and during angina-limited exercise before and 1 hour after intravenous administration of 2 mg of molsidomine. When angina pectoris was prevented after the drug was given (6 of 10 patients), the exercise intensity was increased until the recurrence of angina (3 patients) or until exhaustion (3 patients), and hemodynamic data were recorded at this higher exercise capacity. At rest and during submaximal exercise, molsidomine increased heart rate and decreased cardiac output and mean systemic and pulmonary arterial pressures. The prevention of angina pectoris was attended by lower mean systemic and pulmonary arterial pressures and pressure-rate product; cardiac output and heart rate were unchanged. The greater exercise capacity (+26 percent) after molsidomine was attended by increases in maximal cardiac output (+19 percent) and in arteriovenous oxygen difference (+6 percent); the maximal pressure-rate product was unchanged and systemic vascular resistance was lower. The mechanisms of action of molsidomine are very similar to those of nitrates and imply a decrease in venous and arterial tone. Molsidomine deserves further study in patients with angina or congestive heart failure.

Nitroglycerin and nitrate esters

The expanding applications of nitroglycerin and nitrate esters--in congestive heart failure, in the reduction of infarct size in myocardial infarction and in the long-term prophylaxis of angina--have enhanced the clinical importance of these drugs. This article reviews some of the significant recent investigations of the nitrates and makes specific recommendations regarding clinical use.

Hemodynamics and antianginal effects of high dose oral isosorbide dinitrate after chronic use

In a randomized, double-blind, crossover study, 19 patients with angina were exercised 2 min after 0.4 mg sublingual nitroglycerin and after sublingual placebo and before and 1, 3, and 5 hours after oral isosorbide dinitrate (ISDN) and oral placebo. After initial testing, patients took the dose of ISDN they had had during the study (mean dose 29 mg) for a mean period of 5.6 months before retesting using the same protocol. Compared to placebo, exercise time after sublingual nitroglycerin increased 56% (P less than 0.001) initially and 51% (P less than 0.001) at retest. Compared to placebo, exercise time increased 58% (P less than 0.05) initially and 58% (P less than 0.005) at retest 1 hour after ISDN, 38% (P less than 0.05) initially and 27% (P less than 0.005) at retest 3 hours after ISDN, and 13% (NS) initially and 21% (P less than 0.02) at retest five hours after ISDN. The mean exericse times initially and at retest were not significantly different. Hemodynamic changes (decrease in systolic blood pressure and increase in heart rate) at 15 min persisted through 300 min after ISDN during both initial testing and during retesting. However, these changes were significantly less during retesting. We conclude that a partial tolerance to the hemodynamic effects of the drug develops after chronic use of high dose oral ISDN but that the antianginal efficacy of both sublingual nitroglycerin and oral ISDN is unimpaired.

Sustained hemodynamic and antianginal effect of high dose oral isosorbide dinitrate

Twenty-one patients with documented coronary atherosclerotic heart disease were studied to determine the effect of high dose oral isosorbide dinitrate (ISDN) on heart rate, blood pressure, and exercise time until angina pectoris. Patients were tested in two phases, initially with 0.4 mg of sublingual nitroglycerin and with sublingual placebo, and then with oral ISDN, mean dose 29 mg, and oral placebo. Both phases of the study were conducted in a randomized, double-blind, crossover manner. After ISDN was compared to oral placebo, heart rate increased at 30 to 300 min (P less than 0.01) (peak increase 18 beats/min at 60 min), and systolic blood pressure decreased from 45 to 300 min (P less than 0.005) (peak decrease 18 mm Hg at 60 min). Exercise time at 2 min after sublingual nitroglycerin increased 51% as compared to oral placebo, exercise time increased 54% at 1 hr (P less than 0.005), 37% at 3 hr (P less than 0.01), and 12% at 5 hr (NS). Twelve of 21 patients (57%) improved their exercise time until angina larger than or equal to 25% at 1 hr after oral ISDN. The exercise response to sublingual nitroglycerin was a good predictor of this response to oral ISDN.

Hemodynamic assessment of oral peripheral vasodilator therapy in chronic congestive heart failure: prolonged effectiveness of isosorbide dinitrate

To evaluate the effectiveness of oral vasodilator therapy in chronic congestive heart failure, 20 mg of isosorbide dinitrate or placebo was administered orally in double-blind fashion to 25 patients with congestive heart failure. In 15 patients receiving isosorbide dinitrate, pulmonary arterial wedge pressure decreased 5 minutes to 5 hours after drug administration; the peak reduction was observed at 1 hour (from 23 to 14 mm Hg; P less than 0.001). Wedge pressure decreased to normal (12 mm Hg or less) in 8 of the 15 patients (Group I) but remained greater than 12 mm Hg in 7 (Group II). Reductions in mean systemic arterial pressure, systemic vascular resistance and pressure-time per minute also occurred. Indexes of pump output were unchanged in the 15 who received isosorbide dinitrate but tended to decrease slightly in Group I. Stroke index (from 23 to 26 cc/m2) and stroke work index (from 21.4 to 24.1 g-m/m2) increased slightly but significantly (P less than 0.05) in Group II. Thus the prinicpal hemodynamic action of isorbide dinitrate is marked and sustained reduction in left ventricular filling pressure without pronounced effect on cardiac output. This agent should be used in congestive heart failure primarily for relief of congestive symptoms.

Effect of swallowed isosorbide dinitrate on blood pressure, heart rate and exercise capacity in patients with coronary artery disease

Blood pressures and heart rates were measured with the patients supine and standing after a placebo and small (5 to 10 mg) and large (10 to 30 mg) doses of isosorbide dinitrate were given orally in double-blind fashion to six patients. Compared to the findings after the placebo, the blood pressure level fell and the heart rate increased after the ingestion of isosorbide dinitrate. The changes were more striking with the patients standing than with them supine, and the larger dose of the drug produced greater changes than the smaller dose. The hemodynamic effects were usually apparent at 15 minutes, peaked between 30 and 120 minutes, and were still present at 240 minutes. Two hours after swallowing a 7.5 to 20 mg dose of isosorbide dinitrate or placebo, administered in random fashion, 10 patients with coronary artery disease and angina pectoris underwent graded, treadmill, exercise testing designed to provoke angina only after 3 minutes or more. Nine of them exercised longer and achieved higher maximal heart rates after taking the isosorbide dinitrate. Thus, in man, swallowed isosorbide dinitrate has a dose-related, "long-acting," pharmacologic effect, and when tested by properly designed protocols, it improves exercise capacity. However, because the problems of nitrate tolerance and dependence have not been resolved, the place of oral nitrates in the management of patients with angina pectoris remains uncertain.

Sustained haemodynamic action of nitroglycerin ointment

Intravenous vasodilators have been shown to improve the haemodynamic status of patients in congestive heart failure. However, neither intravenous nor sublingual preparations are suitable for chronic administration or use in ambulatory patients. In this study, nitroglycerin ointment bas administered to 11 patients in congestive heart failure. Mean pulmonary wedge and arterial pressures, as well as systemic blood pressures and heart rate were then monitored for 2 to 5 hours and compared with baseline values. Pulmonary wedge and arterial pressures, as well as systemic systolic arterial pressure, decreased significantly at 15 minutes after application and remained depressed for up to 5 hours. Systemic diastolic pressures fell significantly at 30 minutes and also remained significantly reduced for up to 5 hours. Thus, nitroglycerin ointment may be suitable for chronic vasodilator therapy of congestive heart failure.

Effects of isosorbide dinitrate and nitroglycerin on central circulatory dynamics in coronary artery disease

This study compares the effects and duration of the effects of 5 mg. of sublingual (SL) isosorbide dinitrate (ISD), 20 mg. of oral ISD, and 0.4 mg. of SL nitroglycerin (TNG) on central circulatory dynamics. Twenty-seven patients with coronary artery disease were evaluated with radioisotope techniques and determinations made of heart rate (HR), blood pressure (BP), cardiac index (CI), stroke volume index (SVI), left ventricular enddiastolic volume index (LVEDVI), and left ventricular ejection fraction (LVEF). There were significant and equivalent reductions in BP, SVI, LVEDVI, and CI 15 minutes after TNG, 1 hour after SL ISD, and 4 hours after oral ISD in addition to comparative increases in HR and EF by all drugs at these same time intervals. The effects of TNG were gone at 30 minutes while changes in LVEDVI, LVEF, and CI were present 4 hours after SL ISD and persistent changes in LVEDVI and SVI present 6 hours after oral ISD. We conclude that nitrates have significant effects on both preload and afterload and that the duration of effects of sublingual and oral ISD are truly long acting as compared to TNG.