Single-drug therapy for hypertension in men. A comparison of six antihypertensive agents with placebo. The Department of Veterans Affairs Cooperative Study Group on Antihypertensive Agents

BACKGROUND

Characteristics such as age and race are often cited as determinants of the response of blood pressure to specific antihypertensive agents, but this clinically important issue has not been examined in sufficiently large trials, involving all standard treatments, to determine the effect of such factors.

METHODS

In a randomized, double-blind study at 15 clinics, we assigned 1292 men with diastolic blood pressures of 95 to 109 mm Hg, after a placebo washout period, to receive placebo or one of six drugs: hydrochlorothiazide (12.5 to 50 mg per day), atenolol (25 to 100 mg per day), captopril (25 to 100 mg per day), clonidine (0.2 to 0.6 mg per day), a sustained-release preparation of diltiazem (120 to 360 mg per day), or prazosin (4 to 20 mg per day). The drug doses were titrated to a goal of less than 90 mm Hg for maximal diastolic pressure, and the patients continued to receive therapy for at least one year.

RESULTS

The mean (+/- SD) age of the randomized patients was 59 +/- 10 years, and 48 percent were black. The average blood pressure at base line was 152 +/- 14/99 +/- 3 mm Hg. Diltiazem therapy had the highest rate of success: 59 percent of the treated patients had reached the blood-pressure goal at the end of the titration phase and had a diastolic blood pressure of less than 95 mm Hg at one year. Atenolol was successful by this definition in 51 percent of the patients, clonidine in 50 percent, hydrochlorothiazide in 46 percent, captopril in 42 percent, and prazosin in 42 percent; all these agents were superior to placebo (success rate, 25 percent). Diltiazem ranked first for younger blacks (< 60 years) and older blacks (> or = 60 years), among whom the success rate was 64 percent, captopril for younger whites (success rate, 55 percent), and atenolol for older whites (68 percent). Drug intolerance was more frequent with clonidine (14 percent) and prazosin (12 percent) than with the other drugs.

CONCLUSIONS

Among men, race and age have an important effect on the response to single-drug therapy for hypertension. In addition to cost and quality of life, these factors should be considered in the initial choice of a drug.

Rhythm or rate control in atrial fibrillation--Pharmacological Intervention in Atrial Fibrillation (PIAF): a randomised trial

BACKGROUND

Atrial fibrillation is the most commonly encountered sustained cardiac arrhythmia. Restoration and maintenance of sinus rhythm is believed by many physicians to be superior to rate control only. However, there are no prospective data that compare both therapeutic strategies.

METHODS

The Pharmacological Intervention in Atrial Fibrillation (PIAF) trial was a randomised trial in 252 patients with atrial fibrillation of between 7 days and 360 days duration, which compared rate (group A, 125 patients) with rhythm control (group B, 127 patients). In group A, diltiazem was used as first-line therapy and amiodarone was used in group B. The primary study endpoint was improvement in symptoms related to atrial fibrillation.

FINDINGS

Over the entire observation period of 1 year, a similar proportion of patients reported improvement in symptoms in both groups (76 responders at 12 months in group A vs 70 responders in group B, p=0.317). Amiodarone administration resulted in pharmacological restoration of sinus rhythm in 23% of patients. Walking distance in a 6 min walk test was better in group B compared with group A, but assessment of quality of life showed no differences between groups. The incidence of hospital admission was higher in group B (87 [69%] out of 127 vs 30 [24%] out of 125 in group A, p=0.001). Adverse drug effects more frequently led to a change in therapy in group B (31 [25%] patients compared with 17 [14%] in group A, p=0.036).

INTERPRETATION

With respect to symptomatic improvement in patients with atrial fibrillation, the therapeutic strategies of rate versus rhythm control yielded similar clinical results overall. However, exercise tolerance is better with rhythm control, although hospital admission is more frequent. These data may serve as a basis to select therapy in individual patients.

Comparative pharmacology of calcium antagonists: nifedipine, verapamil and diltiazem

Calcium antagonists (slow channel blocking agents) are a very heterogeneous group of agents with dissimilar structural, electrophysiologic and pharmacologic properties. Nifedipine is a potent, long-acting vasodilator that has proved highly efficacious in relieving anginal symptoms caused by coronary vasospasm. In vivo, it exerts no myocardial depressant effects and has no antiarrhythmic properties. Treatment with nifedipine can safely be combined with administration of a beta receptor blocking agent. VErapamil prolongs atrioventricular (A-V) conduction (A-H interval) in a dose-dependent manner. It is the drug of choice for the treatment of reentrant supraventricular arrhythmias, irrespective of whether reentry occurs within the A-V node or through an accessory pathway (the Wolff-Parkinson-White syndrome). Verapamil is only moderately effective as an antianginal agent. Diltiazem is efficacious for the treatment of angiospastic angina, but its value as an antiarrhythmic agent remains to be delineated.

Randomised trial of effects of calcium antagonists compared with diuretics and beta-blockers on cardiovascular morbidity and mortality in hypertension: the Nordic Diltiazem (NORDIL) study

BACKGROUND

Calcium antagonists are a first-line treatment for hypertension. The effectiveness of diltiazem, a non-dihydropyridine calcium antagonist, in reducing cardiovascular morbidity or mortality is unclear. We compared the effects of diltiazem with that of diuretics, beta-blockers, or both on cardiovascular morbidity and mortality in hypertensive patients.

METHODS

In a prospective, randomised, open, blinded endpoint study, we enrolled 10,881 patients, aged 50-74 years, at health centres in Norway and Sweden, who had diastolic blood pressure of 100 mm Hg or more. We randomly assigned patients diltiazem, or diuretics, beta-blockers, or both. The combined primary endpoint was fatal and non-fatal stroke, myocardial infarction, and other cardiovascular death. Analysis was done by intention to treat.

FINDINGS

Systolic and diastolic blood pressure were lowered effectively in the diltiazem and diuretic and beta-blocker groups (reduction 20.3/18.7 vs 23.3/18.7 mm Hg; difference in systolic reduction p<0.001). A primary endpoint occurred in 403 patients in the diltiazem group and in 400 in the diuretic and beta-blocker group (16.6 vs 16.2 events per 1000 patient-years; relative risk 1.00 [95% CI 0.87-1.15], p=0.97). Fatal and non-fatal stroke occurred in 159 patients in the diltiazem group and in 196 in the diuretic and beta-blocker group (6.4 vs 7.9 events per 1000 patient-years; 0.80 [0.65-0.99], p=0.04) and fatal and non-fatal myocardial infarction in 183 and 157 patients (7.4 vs 6.3 events per 1000 patient-years; 1.16 [0.94-1.44], p=0.17).

INTERPRETATION

Diltiazem was as effective as treatment based on diuretics, beta-blockers, or both in preventing the combined primary endpoint of all stroke, myocardial infarction, and other cardiovascular death.

The effect of diltiazem on mortality and reinfarction after myocardial infarction

We studied the effect of diltiazem on mortality and reinfarction in 2466 patients with previous infarction from 38 hospitals in the United States and Canada. The patients were randomly assigned to receive diltiazem (240 mg per day, n = 1234) or placebo (n = 1232) and followed for 12 to 52 months (mean, 25). Total mortality rates were nearly identical among the two treatment groups (167 and 166, respectively), as were cumulative mortality rates. There were 11 percent fewer first recurrent cardiac events (death from cardiac causes or nonfatal reinfarction) in the diltiazem group than in the placebo group (202 vs. 226; Cox hazard ratio, 0.90; 95 percent confidence limits, 0.74 and 1.08). A significant (P = 0.0042) bidirectional interaction between diltiazem and pulmonary congestion was observed on x-ray examination. In 1909 patients without pulmonary congestion, diltiazem was associated with a reduced number of cardiac events (hazard ratio, 0.77; 95 percent confidence limits, 0.61 and 0.98); in 490 patients with pulmonary congestion, diltiazem was associated with an increased number of cardiac events (hazard ratio, 1.41; 95 percent confidence limits, 1.01 and 1.96). A similar pattern was observed with respect to the ejection fraction, which was dichotomized at 0.40. Thus, diltiazem exerted no overall effect on mortality or cardiac events in this population of patients with previous infarction. This neutral effect reflected a diltiazem-related reduction in cardiac events in the majority of patients without left ventricular dysfunction and an increase in such events in the minority of patients with left ventricular dysfunction.

Revival of the radial artery for coronary artery bypass grafting

Eighteen years after its first introduction for coronary artery revascularization, the radial artery (RA) was reinvestigated because of unexpected good long-term results in the early series. Since July 1989, 104 patients underwent myocardial revascularization using 122 RA grafts (18 patients received two grafts). The left internal mammary artery (IMA) was concomitantly used as a pedicled graft in 100 cases and the right IMA in 19 cases; a free IMA graft was used in 29 cases and a saphenous vein graft in 24 cases. A mean of 2.8 grafts per patient were performed. Nine patients underwent associated procedures: carotid endarterectomy (3), aortic valve replacement (3), Bigelow procedure (1), and mitral valve repair (2). The target artery receiving the RA was the circumflex (n = 59), diagonal (n = 29), right coronary (n = 27), and left anterior descending (n = 7). One patient died (0.96%) and 2 had perioperative myocardial infarct. Sternal wound infection was noted in 3 cases of double IMA implantation. No ischemia of the hand was observed. All patients received diltiazem started intraoperatively and continued after discharge. In addition aspirin (100 mg/day) was given at discharge. Early angiographic controls (less than 2 weeks) were obtained in the first 50 consecutive patients and revealed 56 of 56 patent RA grafts, 48 of 48 patent left IMA grafts, 11 of 11 patent right IMA grafts, 14 of 18 patent free IMA grafts, and 8 of 9 patent vein grafts.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium channel blocking agents in the treatment of cardiovascular disorders. Part II: Hemodynamic effects and clinical applications

The calcium channel blocking agents have multiple hemodynamic effects that make them potentially valuable in treating many cardiovascular disorders. They are potent dilators of coronary and peripheral arteries and in isolated tissue preparations exert potent negative inotropic, chronotropic, and dromotropic effects. In intact animals the peripheral arterial vasodilatation induces reflex-mediated adrenergic activity, which opposes the direct negative inotropic, chronotropic, dromotropic, and hypotensive effects. The individual calcium channel blockers have different relative potencies on various cardiovascular functions. The net hemodynamic and electrophysiologic effect of each agent, therefore, results from a complex interplay of direct and reflex phenomena. The clinical efficacy of these agents in classic angina pectoris relates to their ability to decrease afterload, myocardial contractility, and heart rate and increase coronary blood flow. The agents have been used to prevent coronary spasm in Prinzmetal's variant angina. The negative inotropic effects of verapamil are valuable in improving the symptoms and hemodynamic disturbances of hypertrophic cardiomyopathy. The role of these agents in treating arterial hypertension, unstable angina pectoris, acute myocardial infarction, and ischemia during cardiopulmonary bypass needs to be determined.

Effects of ranolazine with atenolol, amlodipine, or diltiazem on exercise tolerance and angina frequency in patients with severe chronic angina: a randomized controlled trial

CONTEXT

Many patients with chronic angina experience anginal episodes despite revascularization and antianginal medications. In a previous trial, antianginal monotherapy with ranolazine, a drug believed to partially inhibit fatty acid oxidation, increased treadmill exercise performance; however, its long-term efficacy and safety have not been studied in combination with beta-blockers or calcium antagonists in a large patient population with severe chronic angina.

OBJECTIVES

To determine whether, at trough levels, ranolazine improves the total exercise time of patients who have symptoms of chronic angina and who experience angina and ischemia at low workloads despite taking standard doses of atenolol, amlodipine, or diltiazem and to determine times to angina onset and to electrocardiographic evidence of myocardial ischemia, effect on angina attacks and nitroglycerin use, and effect on long-term survival in an open-label observational study extension.

DESIGN, SETTING, AND PATIENTS

A randomized, 3-group parallel, double-blind, placebo-controlled trial of 823 eligible adults with symptomatic chronic angina who were randomly assigned to receive placebo or 1 of 2 doses of ranolazine. Patients treated at the 118 participating ambulatory outpatient settings in several countries were enrolled in the Combination Assessment of Ranolazine In Stable Angina (CARISA) trial from July 1999 to August 2001 and followed up through October 31, 2002.

INTERVENTION

Patients received twice-daily placebo or 750 mg or 1000 mg of ranolazine. Treadmill exercise 12 hours (trough) and 4 hours (peak) after dosing was assessed after 2, 6 (trough only), and 12 weeks of treatment.

MAIN OUTCOME MEASURES

Change in exercise duration, time to onset of angina, time to onset of ischemia, nitroglycerin use, and number of angina attacks.

RESULTS

Trough exercise duration increased by 115.6 seconds from baseline in both ranolazine groups (pooled) vs 91.7 seconds in the placebo group (P =.01). The times to angina and to electrocardiographic ischemia also increased in the ranolazine groups, at peak more than at trough. The increases did not depend on changes in blood pressure, heart rate, or background antianginal therapy and persisted throughout 12 weeks. Ranolazine reduced angina attacks and nitroglycerin use by about 1 per week vs placebo (P<.02). Survival of 750 patients taking ranolazine during the CARISA trial or its associated long-term open-label study was 98.4% in the first year and 95.9% in the second year.

CONCLUSION

Twice-daily doses of ranolazine increased exercise capacity and provided additional antianginal relief to symptomatic patients with severe chronic angina taking standard doses of atenolol, amlodipine, or diltiazem, without evident adverse, long-term survival consequences over 1 to 2 years of therapy.

Diltiazem and reinfarction in patients with non-Q-wave myocardial infarction. Results of a double-blind, randomized, multicenter trial

We performed a multicenter, double-blind, randomized study to evaluate the effect of diltiazem on reinfarction after a non-Q-wave myocardial infarction. Nine centers enrolled 576 patients: 287 received diltiazem (90 mg every six hours) and 289 received placebo. Treatment was initiated 24 to 72 hours after the onset of infarction and continued for up to 14 days. The primary end point, reinfarction, was defined as an abnormal reelevation of MB creatine kinase in plasma within 14 days. Reinfarction occurred in 27 patients in the placebo group (9.3 percent) and in 15 in the diltiazem group (5.2 percent)--a 51.2 percent reduction in cumulative life-table incidence (P = 0.0297; 90 percent confidence interval, 7 to 67 percent). Diltiazem reduced the frequency of refractory postinfarction angina (a secondary end point) by 49.7 percent (P = 0.0345; 90 percent confidence interval, 6 to 73 percent). Mortality was similar in the two groups (3.1 and 3.8 percent, respectively, in the placebo and diltiazem groups), but adverse drug reactions (most of which were mild) were more common in the diltiazem group. Nevertheless, the drug was well tolerated, despite concurrent treatment with beta-blockers in 61 percent of the patients. We conclude that diltiazem was effective in preventing early reinfarction and severe angina after non-Q-wave infarction and that it was also safe and generally well tolerated.

Ventricular rate control in chronic atrial fibrillation during daily activity and programmed exercise: a crossover open-label study of five drug regimens

OBJECTIVES

We compared the effects of five pharmacologic regimens on the circadian rhythm and exercise-induced changes of ventricular rate (VR) in patients with chronic atrial fibrillation (CAF).

BACKGROUND

Systematic comparison of standardized drug regimens on 24 h VR control in CAF have not been reported.

METHODS

In 12 patients (11 male, 69+/-6 yr) with CAF, the effects on VR by 5 standardized daily regimens: 1) 0.25 mg digoxin, 2) 240 mg diltiazem-CD, 3) 50 mg atenolol, 4) 0.25 mg digoxin + 240 mg diltiazem-CD, and 5) 0.25 mg digoxin + 50 mg atenolol; were studied after 2 week treatment assigned in random order. The VR data were analyzed by ANOVA with repeated measures. The circadian phase differences were evaluated by cosinor analysis.

RESULTS

The 24-h mean (+/-SD) values of VR (bpm) were - digoxin: 78.9 +/- 16.3, diltiazem: 80.0+/-15.5, atenolol: 75.9+/-11.7, digoxin + diltiazem: 67.3+/-14.1 and digoxin + atenolol: 65.0+/-9.4. Circadian patterns were significant in each treatment group (p < 0.001). The VR on digoxin + atenolol was significantly lower than that on digoxin (p < 0.0001), diltiazem (p < 0.0002) and atenolol (p < 0.001). The time of peak VR on Holter was significantly delayed with regimens 3 and 5 which included atenolol (p < 0.03). During exercise, digoxin and digoxin + atenolol treatments resulted in the highest and lowest mean VR respectively. The exercise Time-VR plots of all groups were nearly parallel (p = ns). The exercise duration was similar in all treatment groups (p = ns).

CONCLUSIONS

This study indicates that digoxin and diltiazem, as single agents at the doses tested, are least effective for controlling ventricular rate in atrial fibrillation during daily activity. Digoxin + atenolol produced the most effective rate control reflecting a synergistic effect on the AV node. The data provides a basis for testing the effects of chronic suppression of diurnal fluctuations of VR on left atrial and ventricular function in CAF.

Calcium channel blocking agents in the treatment of cardiovascular disorders. Part I: Basic and clinical electrophysiologic effects

Calcium ions play an important role in the cardiovascular system. They are involved in electrophysiologic processes, link excitation to muscular contraction, control energy storage and utilization, and constrict vascular smooth muscle in coronary and systemic arteries. A new group of pharmacologic agents that block the passage of calcium ions across cell membranes has been developed. These agents act during the slow inward current of cellular depolarization. The most extensive clinical experience has been obtained with four of these agents: verapamil, nifedipine, perhexiline, and diltiazem. Verapamil, which has profound electrophysiologic effects on the slow inward current, is emerging as a valuable antiarrhythmic agent. Re-entrant supraventricular arrhythmias, such as paroxysmal supraventricular tachycardia, are particularly amenable to treatment with intravenous verapamil. Preliminary trials of long-term therapy with oral verapamil for control of atrial fibrillation, atrial flutter, and paroxysmal supraventricular tachycardia suggest that this agent is effective for therapy of these arrhythmias.

Asymptomatic Cardiac Ischemia Pilot (ACIP) study two-year follow-up: outcomes of patients randomized to initial strategies of medical therapy versus revascularization

BACKGROUND

Patients with ischemia during stress testing and ambulatory ECG monitoring have an increased risk of cardiac events, but it is not known whether their prognosis is improved by more aggressive treatment with anti-ischemic drugs or revascularization.

METHODS AND RESULTS

The Asymptomatic Cardiac Ischemia Pilot study randomized 558 such patients who had coronary anatomy suitable for revascularization to three treatment strategies: angina-guided drug therapy (n=183), angina plus ischemia-guided drug therapy (n=183), or revascularization by angioplasty or bypass surgery (n=192). Two years after randomization, the total mortality was 6.6% in the angina-guided strategy, 4.4% in the ischemia-guided strategy, and 1.1% in the revascularization strategy (P<.02). The rate of death or myocardial infarction was 12.1% in the angina-guided strategy, 8.8% in the ischemia-guided strategy, and 4.7% in the revascularization strategy (P<.04). The rate of death, myocardial infarction, or recurrent cardiac hospitalization was 41.8% in the angina-guided strategy, 38.5% in the ischemia-guided strategy, and 23.1% in the revascularization strategy (P<.001). Pairwise testing revealed significant differences between the revascularization and angina-guided strategies for each comparison.

CONCLUSIONS

A strategy of initial revascularization appears to improve the prognosis of this population compared with angina-guided medical therapy. A larger long-term study is needed to confirm this benefit and to adequately test the potential of more aggressive drug therapy.

Diltiazem. A review of its pharmacological properties and therapeutic efficacy

Diltiazem is an orally and intravenously active calcium channel blocking agent shown to be an effective and well-tolerated treatment for stable angina and angina due to coronary artery spasm. Its efficacy in these diseases has generally been similar to that of nifedipine or verapamil - alternative calcium channel blockers with which diltiazem has many electrophysiological, haemodynamic, and antiarrhythmic similarities. The antianginal mechanism of diltiazem cannot be precisely described; however, it appears to increase myocardial oxygen supply and decrease myocardial oxygen demand, mainly by coronary artery dilatation and/or via both direct and indirect haemodynamic alterations. Diltiazem has also shown substantial efficacy in the treatment of unstable angina, hypertension, and supraventricular tachyarrhythmias, but further study is necessary before its place in the treatment of these diseases may be clearly established. Although headache due to peripheral vasodilatation and depression of atrioventricular nodal conduction may be troublesome, side effects occur in only 2 to 10% of patients receiving diltiazem and are generally minor in nature. Thus, diltiazem offers a worthwhile alternative to other agents currently available for the treatment of angina pectoris. Although the infrequency of serious side effects may offer an advantage, its relative place in therapy compared with that of other calcium channel blockers remains to be clarified.

A preliminary study of diltiazem in the prevention of coronary artery disease in heart-transplant recipients

BACKGROUND

Accelerated coronary artery disease is a major cause of late morbidity and mortality among heart-transplant recipients. Because calcium-channel blockers can suppress diet-induced atherosclerosis in laboratory animals, we assessed the efficacy of diltiazem in preventing coronary artery disease in transplanted hearts.

METHODS

Consecutive eligible cardiac-transplant recipients were randomly assigned to receive diltiazem (n = 52) or no calcium-channel blocker (n = 54). Coronary angiograms obtained early after cardiac transplantation and annually thereafter were used for the visual assessment of the extent of coronary artery disease. The average diameters of identical coronary artery segments were measured on the angiograms obtained at base line and at the first and second follow-up examinations.

RESULTS

In the 57 patients who had all three angiograms, the average coronary artery diameter (+/- SD) 0.27 decreased in the group that received no calcium-channel blocker from 2.41 +/- 0.27 mm at base line to 2.19 +/- 0.28 mm at one year, and to 2.22 +/- 0.26 mm at two years (P < 0.001 for both years). The average diameter in the diltiazem group changed little from the base-line value of 2.32 +/- 0.22 mm (2.32 +/- 0.27 mm at one year and 2.36 +/- 0.22 mm at two years). The average change in the diameter of the segment differed significantly between the two treatment groups (P < 0.001), and the estimated effect of treatment changed only negligibly after adjustment for other relevant clinical variables. New angiographic evidence of coronary artery disease developed in 14 patients not given calcium-channel blockers, as compared with 5 diltiazem-treated patients (P = 0.082). Coronary stenoses greater than 50 percent of the luminal diameter developed in seven patients not given calcium-channel blockers, as compared with two patients given diltiazem; death due to coronary artery disease or retransplantation occurred in five patients in the group that did not receive calcium-channel blockers and none of those who received diltiazem.

CONCLUSIONS

Our preliminary results suggest that diltiazem can prevent the usual reduction in the diameter of the coronary artery in cardiac-transplant recipients, but further follow-up will be required to determine whether diltiazem can decrease the long-term incidence of symptomatic coronary artery disease.

Exertional angina pectoris caused by coronary arterial spasm: effects of various drugs

In four patients with exertional angina induced by arm exercise, coronary arteriograms taken before, during and after the attack demonstrated that spasm appeared in the large coronary artery supplying the area of myocardium shown to be ischemic in the electrocardiogram during the attack. The spasm disappeared with subsidence of the attack after administration of nitroglycerin. Anginal attacks induced by treadmill exercise were not suppressed by propranolol, 60 mg orally, in two of the four patients. However, such attacks were suppressed in all patients by oral administration of diltiazem (90 mg, four patients) or nifedipine (20 mg, three patients) or intramuscular injection of phentolamine (0.2 mg/kg body weight, three patients). It is concluded that coronary arterial spasm can be induced by exercise and can cause exertional angina in some patients. Diltiazem and nifedipine, calcium antagonistic drugs, prevent spasm.

Failure of diltiazem to prevent restenosis after percutaneous transluminal coronary angioplasty

This prospective randomized trial was carried out in 92 patients who underwent a successful percutaneous transluminal coronary angioplasty (PTCA) and had no evidence of coronary spasm before PTCA. All patients were premedicated with calcium antagonists and platelet inhibitors and received platelet inhibitors (aspirin and dipyridamole) for 6 months after PTCA. The diltiazem group (46 patients with 50 stenoses successfully dilated) received diltiazem, 90 mg three times a day by mouth for 3 months after PTCA; in the control group (46 patients, 53 stenoses), calcium antagonists were discontinued immediately after PTCA. All patients underwent a control angiogram 5 to 10 months after PTCA unless recurrence of angina dictated its need earlier. Baseline characteristics were similar in both groups, except for the number of diseased vessels greater than or equal to 70%, which was higher in the control group (1.2 +/- 0.55 vs 0.9 +/- 0.39 for the diltiazem group, p less than 0.05). In the diltiazem group, the degree of stenosis increased from 38 +/- 15% immediately after PTCA to 42 +/- 23% at repeat angiography 8.24 +/- 4.79 months after PTCA and there were seven restenoses. In the control group, the degree of stenosis increased from 37 +/- 12% to 44 +/- 23% at repeat angiography 8.26 +/- 4.91 months after PTCA and there were 10 restenoses (NS vs the diltiazem group). In conclusion, in patients without variant angina before PTCA, adjunction of diltiazem to platelet inhibitors does not decrease the incidence of restenosis. These data suggest that coronary spasm is not the major mechanism of restenosis.

Effect of single-drug therapy on reduction of left ventricular mass in mild to moderate hypertension: comparison of six antihypertensive agents. The Department of Veterans Affairs Cooperative Study Group on Antihypertensive Agents

BACKGROUND

Antihypertensive drugs may differ in their ability to reduce LV mass. Covariates other than drug selection, such as pretreatment LV mass, body weight, the magnitude of blood pressure reduction, race, and age may modify the response of LV mass to therapy.

METHODS AND RESULTS

Patients with mild to moderate hypertension (diastolic blood pressure, 95 to 109 mm Hg) were randomly allocated to treatment with atenolol, captopril, clonidine, diltiazem, hydrochlorothiazide, or prazosin in a double-masked trial. Patients achieving the goal diastolic blood pressure of <90 mm Hg during drug titration entered a 1-year maintenance period. Longitudinal analysis examined changes from baseline echocardiogram in LV mass at 8 weeks and at 1 year, statistically adjusted for pretreatment LV mass, systolic blood pressure, body weight, sodium excretion, physical activity, race, and age. Significant reductions at 1 year in adjusted LV mass were seen for patients in the highest tertile of pretreatment LV mass treated with hydrochlorothiazide (mean, -42.9; 95% confidence limits, -65.5, -20.2 g), captopril (mean, -38.7; 95% confidence limits, -61.0, -16.4 g), and atenolol (mean, -28.1; 95% confidence limits, -50.9, -5.3 g). These treatment effects differed from those of prazosin, diltiazem, or clonidine.

CONCLUSIONS

Antihypertensive drugs have disparate effects on LV mass independent of the magnitude of blood pressure reduction. Patients with adequate blood pressure control on captopril, hydrochlorothiazide, and atenolol show a reduction of LV mass after 1 year of treatment, whereas patients on diltiazem, clonidine, or prazosin do not.

Inhaled nitric oxide as a screening agent for safely identifying responders to oral calcium-channel blockers in primary pulmonary hypertension

In a subset of patients with primary pulmonary hypertension (PPH), high doses of oral calcium-channel blockers (CCB) produce a sustained clinical and haemodynamic improvement. However, significant side-effects have been reported during acute testing with CCB. Therefore, to identify accurately patients who may benefit from long-term CCB therapy, there is a need for a safe, potent and short-acting vasodilator. The aim of this study was to compare the acute response to inhaled nitric oxide (NO) and oral high doses of CCB in 33 consecutive patients with PPH. A significant acute vasodilator response was defined by a fall in both mean pulmonary artery pressure and total pulmonary resistance by >20%. Ten patients responded acutely to NO, nine of whom responded acutely to CCB, without any complications. The 23 other patients failed to respond to NO and CCB. In these nonresponders, nine serious adverse events were observed with CCB (38%). There was no clinical or baseline haemodynamic feature predicting acute vasodilator response. Long-term oral treatment with CCB was restricted to the nine acute responders and a sustained clinical and haemodynamic improvement was observed in only six patients. In primary pulmonary hypertension, the acute response rate to high doses of calcium-channel blockers is low (27%). Serious adverse reactions to high doses of calcium-channel blockers during acute testing are frequently observed in nonresponders. It is concluded that nitric oxide may be used as a screening agent for safely identifying patients with primary pulmonary hypertension who respond acutely to calcium-channel blockers and may benefit from long-term treatment with these agents.

Treatment of variant angina with drugs: a survey of 11 cardiology institutes in Japan

Data from 11 cardiology institutes in Japan were examined to determine the effectiveness of drug therapy, especially with calcium antagonists, on variant angina. The subjects were 243 males and 43 females, most of whom were 40-59 years old. Coronary artery lesions were found in 92 of 162 patients (56.7%) in whom cinecoronary arteriograms were done. The efficacy rates of nifedipine, diltiazem and verapamil were 94.0%, 90.8% and 85.7%, respectively. Regardless of the presence or absence of organic coronary artery lesions, the drugs were effective in 92.3% of the patients with normal or nearly normal coronary arteries and in 82.6% of those with stenosis of more than 50% of the luminal diameter. These findings suggest that the drugs are effective through their antispasmodic actions.

Retinitis pigmentosa: rod photoreceptor rescue by a calcium-channel blocker in the rd mouse

Retinitis pigmentosa is an inherited degenerative disease of photoreceptors leading to blindness. A well-characterized model for this disease is provided by the retinal degeneration mouse, in which the gene for the rod cGMP phosphodiesterase is mutated, as in some affected human families. We report that D-cis-diltiazem, a calcium-channel blocker that also acts at light-sensitive cGMP-gated channels, rescued photoreceptors and preserved visual function in the retinal degeneration mouse. The long record of diltiazem prescription in cardiology should facilitate the design of clinical trials for some forms of retinitis pigmentosa.

A pharmacological analysis of the pathophysiological mechanisms of posttraumatic spinal cord ischemia

A pharmacological analysis was carried out to determine the possible role of aberrant calcium fluxes, vasoactive arachidonic acid metabolites, and microvascular lipid peroxidation in the development of posttraumatic spinal cord white matter ischemia. Pentobarbital-anesthetized cats were treated intravenously 30 minutes before a 500-gm-cm contusion injury to the lumbar spinal cord with one of the following test drugs: the Ca++ channel antagonists verapamil, diltiazem, or nifedipine; the cyclo-oxygenase inhibitors ibuprofen or meclofenamate; the thromboxane A2 (TXA2) synthetase inhibitor furegrelate sodium; or the stable epoprostenol (prostacyclin, or PGI2) analogue ciprostene calcium alone or in combination with furegrelate sodium. Another group of animals was pretreated for 5 days before spinal injury with a combination of the antioxidants vitamin E and selenium in high doses. The hydrogen clearance technique was used to make repeated measurements of spinal cord blood flow (SCBF) in the dorsolateral funiculus of the injured segment before and for 4 hours after injury. In 11 untreated uninjured cats, the mean preinjury SCBF was 12.7 +/- 1.5 ml/100 gm/min. Following contusion, there was a progressive decline in SCBF to 6.8 +/- 0.4 ml/100 gm/min, or 53.5% of the preinjury level at 4 hours. In comparison, the Ca++ antagonists diltiazem and nifedipine (but not verapamil) prevented a significant posttraumatic decrease in SCBF. Similarly, both cyclo-oxygenase inhibitors (ibuprofen and meclofenamate) maintained SCBF within normal limits (10 ml/100 gm/min or greater). However, neither TXA2 synthetase inhibition nor the stable PGI2 analogue alone had a significant effect in preventing ischemia, whereas a combination of the two agents did serve to support SCBF. The most impressive preservation of posttraumatic SCBF, however, was observed in the antioxidant-treated animals. Based upon these results, a hypothesis is presented concerning the pathogenesis of posttraumatic central nervous system ischemia which integrates an injury-induced rise in intracellular Ca++, the increased synthesis of vasoactive prostanoids (such as prostaglandin F2 alpha and TXA2), and progressive microvascular lipid peroxidation.

Calcium channel blockers in the management of low-tension and open-angle glaucoma

Fifty-six patients with either open-angle or low-tension glaucoma who were concurrently taking calcium channel blockers were compared to similar groups not taking such medications for a mean follow-up period of 3.4 years. Serial stereoscopic optic nerve photographs and visual fields of all patients were evaluated for evidence of glaucomatous progression. In patients with low-tension glaucoma, there was a significant difference in the progression of visual field defects, with only two of 18 eyes (11%) of patients taking calcium channel blockers, compared to ten of 18 eyes (56%) of controls showing new visual field defects. Similarly, low-tension glaucoma patients taking calcium channel blocker therapy demonstrated no evidence of progressive optic nerve damage, compared to eight of 18 control eyes (44%). In contrast, patients with open-angle glaucoma taking calcium channel blockers showed no marked difference in the progression of glaucoma, compared to controls. These findings suggest that calcium channel blockers may be useful in the management of low-tension glaucoma.

Comparative clinical electrophysiologic effects of diltiazem, verapamil and nifedipine: a review

The slow channel blocking agents--diltiazem, verapamil and nifedipine--have generated clinical interest for the treatment of a variety of cardiovascular disorders. These agents, despite a similar basic mechanism of action, produce disparate clinical cardiac electrophysiologic effects in human beings. In usual doses, the acute administration of diltiazem slows heart rate. Verapamil and nifedipine, however, increase heart rate. Although diltiazem and verapamil produce equivalent slowing of atrioventricular (A-V) nodal conduction, verapamil prolongs A-V nodal refractoriness to a greater degree. In contrast, nifedipine facilitates A-V nodal conduction and shortens A-V nodal refractoriness. Knowledge of these differences may aid in the appropriate selection of specific slow channel blocking agents in specific clinical situations.

Comparison of propranolol, diltiazem, and nifedipine in the treatment of ambulatory ischemia in patients with stable angina. Differential effects on ambulatory ischemia, exercise performance, and anginal symptoms. The ASIS Study Group

Episodes of transient myocardial ischemia during ambulatory activities are common in patients with stable coronary artery disease and who are often asymptomatic. Selection of therapy for episodes of asymptomatic ischemia is limited by a lack of direct comparative studies. To determine the most effective monotherapy for patients with stable angina and a high frequency of asymptomatic ischemic episodes, propranolol-LA (mean daily dose, 293 mg), diltiazem-SR (mean daily dose, 350 mg), nifedipine (mean daily dose, 79 mg) were each compared with placebo, each for 2 weeks, in a randomized, double-blinded, crossover trial. Entry criteria were a positive exercise treadmill test during placebo therapy characterized by 1.0 mm or more ST segment depression and angina pectoris, and six or more episodes of transient ST segment depression of 1.0 mm or more on a 48-hour ambulatory electrocardiogram. One hundred ninety-four patients were screened, 63 were eligible and received randomized therapy, of which 56 patients completed at least two of the four treatment periods and were included in an intent-to-treat analysis. Fifty patients completed all four treatment phases and were included in the protocol-completed analysis. Anti-ischemia efficacy was assessed by 48-hour ambulatory electrocardiographic monitoring, exercise treadmill tests, and anginal diaries. Ninety-four percent of all episodes of ambulatory ischemia were asymptomatic. Compared with placebo, only propranolol was associated with a marked reduction in all manifestations of asymptomatic ischemia during ambulatory electrocardiographic monitoring (2.3 versus 1.0 episodes/24 hr; mean duration of ischemia per 24 hours, 43.6 versus 5.7 minutes; both p less than 0.0001). Diltiazem's reduction of the frequency of episodes compared with placebo (2.3 versus 1.9 episodes/24 hr) was associated with a trend (p = 0.08) in the protocol-completed analysis and with a significant reduction in the intent-to-treat analysis (p = 0.03). Nifedipine had no significant effect on any measured variable of ambulatory ischemia. The dosages of medication used may have been excessive for some patients, and a more beneficial effect may have been evident at a lower dose. In contrast to the marked effects of the active agents on ambulatory asymptomatic ischemia, the effects on exercise performance and angina pectoris were slight. The active agents modestly improved treadmill exercise duration time until 1 mm ST segment depression (3%), and only propranolol and diltiazem had significant effects. Only diltiazem significantly prolonged the total exercise time. Anginal frequency was significantly decreased by both propranolol and diltiazem.(ABSTRACT TRUNCATED AT 400 WORDS)

Diltiazem treatment for pre-clinical hypertrophic cardiomyopathy sarcomere mutation carriers: a pilot randomized trial to modify disease expression

OBJECTIVES

The study sought to assess the safety, feasibility, and effect of diltiazem as disease-modifying therapy for at-risk hypertrophic cardiomyopathy (HCM) mutation carriers.

BACKGROUND

HCM is caused by sarcomere mutations and characterized by left ventricular hypertrophy (LVH) with increased risk of heart failure and sudden death. HCM typically cannot be diagnosed early in life, although subtle phenotypes are present. Animal studies indicate that intracellular calcium handling is altered before LVH develops. Furthermore, early treatment with diltiazem appeared to attenuate disease emergence.

METHODS

In a pilot, double-blind trial, we randomly assigned 38 sarcomere mutation carriers without LVH (mean 15.8 years of age) to therapy with diltiazem 360 mg/day (or 5 mg/kg/day) or placebo. Treatment duration ranged from 12 to 42 months (median 25 months). Study procedures included electrocardiography, echocardiography, cardiac magnetic resonance imaging, and serum biomarker measurement.

RESULTS

Diltiazem was not associated with serious adverse events. Heart rate and blood pressure did not differ significantly between groups. However, mean left ventricular (LV) end-diastolic diameter improved toward normal in the diltiazem group but decreased further in controls (change in z-scores, +0.6 vs. -0.5; p < 0.001). Mean LV thickness-to-dimension ratio was stable in the diltiazem group but increased in controls (-0.02 vs. +0.15; p = 0.04). Among MYBPC3 mutation carriers, LV wall thickness and mass, diastolic filling, and cardiac troponin I levels improved in those taking diltiazem compared with controls. Four participants developed overt HCM, 2 in each treatment group.

CONCLUSIONS

Pre-clinical administration of diltiazem is safe and may improve early LV remodeling in HCM. This novel strategy merits further exploration. (Treatment of Preclinical Hypertrophic Cardiomyopathy With Diltiazem; NCT00319982).