Prospective Randomized Evaluation Of The Vascular Effects Of Norvasc Trial Research Articles

Effect of inter-individual blood pressure variability on the progression of atherosclerosis in carotid and coronary arteries: a post hoc analysis of the NORMALISE and PREVENT studies.

To investigate the relationship between visit-to-visit blood pressure variability (BPV) and the progression of both carotid and coronary artery disease (CAD). Data from two cardiovascular endpoint studies [Norvasc for Regression of Manifest Atherosclerotic Lesions by Intravascular Sonographic Evaluation (NORMALISE) and Prospective Randomized Evaluation of the Vascular Effects of Norvasc Trial (PREVENT)] were analysed separately. Systolic BPV was assessed as within-subject standard deviation of systolic BP across visits from 12-weeks onwards. Follow-up was 24 months (NORMALISE) or 36 months (PREVENT). Any association between BPV and progression of atherosclerosis was assessed using quantitative coronary angiography (QCA), intravascular ultrasound (IVUS), or B-mode ultrasound (depending on study). Patients from NORMALISE (n = 261) and PREVENT (n = 688 for QCA; n = 364 for ultrasound) were stratified within study according to median systolic BPV. No significant difference in change of minimal luminal diameter (by QCA in PREVENT) or change in percent atheroma volume or normalized total atheroma volume (by IVUS in NORMALISE) was detected for subjects with low BPV (BPV < median) compared with high BPV (BPV ≥ median), regardless of treatment. In PREVENT, a significantly greater reduction in maximum carotid intima-media thickness (IMT) (left and right common carotid artery far wall) was observed for patients with BPV < median compared with those with BPV ≥ median [least squares mean difference 0.06 (95% confidence interval 0.01, 0.11); P = 0.0271], after adjusting for treatment, carotid artery segment (left or right), baseline maximum carotid IMT, and other baseline and cardiovascular risk factors/covariates. In patients with existing CAD and well-controlled BP, visit-to-visit BPV was not associated with progression of coronary atherosclerosis; however, a significantly greater reduction in maximum carotid IMT was observed for patients with low BPV.

EFFECT OF INTER-INDIVIDUAL BLOOD PRESSURE VARIABILITY ON THE PROGRESSION OF ATHEROSCLEROSIS IN CAROTID AND CORONARY ARTERIES: A POST HOC ANALYSIS OF THE NORMALISE AND PREVENT STUDIES

Aims To investigate the relationship between visit-to-visit blood pressure variability (BPV) and the progression of both carotid and coronary artery disease (CAD). Methods and results Data from two cardiovascular endpoint studies [Norvasc for Regression of Manifest Atherosclerotic Lesions by Intravascular Sonographic Evaluation (NORMALISE) and Prospective Randomized Evaluation of the Vascular Effects of Norvasc Trial (PREVENT)] were analysed separately. Systolic BPV was assessed as within-subject standard deviation of systolic BP across visits from 12-weeks onwards. Follow-up was 24 months (NORMALISE) or 36 months (PREVENT). Any association between BPV and progression of atherosclerosis was assessed using quantitative coronary angiography (QCA), intravascular ultrasound (IVUS), or B-mode ultrasound (depending on study). Patients from NORMALISE (n = 261) and PREVENT (n = 688 for QCA; n = 364 for ultrasound) were stratified within study according to median systolic BPV. No significant difference in change of minimal luminal diameter (by QCA in PREVENT) or change in percent atheroma volume or normalized total atheroma volume (by IVUS in NORMALISE) was detected for subjects with low BPV (BPV < median) compared with high BPV (BPV ≥ median), regardless of treatment. In PREVENT, a significantly greater reduction in maximum carotid intima-media thickness (IMT) (left and right common carotid artery far wall) was observed for patients with BPV < median compared with those with BPV ≥ median [least squares mean difference 0.06 (95% confidence interval 0.01, 0.11); P = 0.0271], after adjusting for treatment, carotid artery segment (left or right), baseline maximum carotid IMT, and other baseline and cardiovascular risk factors/covariates. Conclusions In patients with existing CAD and well-controlled BP, visit-to-visit BPV was not associated with progression of coronary atherosclerosis; however, a significantly greater reduction in maximum carotid IMT was observed for patients with low BPV.

Serum levels of thiobarbituric acid reactive substances predict cardiovascular events in patients with stable coronary artery disease: A longitudinal analysis of the PREVENT study

The objective of this study was to test the predictive value of an oxidative stress biomarker in 634 patients from the Prospective Randomized Evaluation of the Vascular Effects of Norvasc Trial (PREVENT). Oxidative stress contributes to mechanisms of atherosclerosis and plaque instability. Biomarkers of oxidation, such as malondialdehyde (MDA), may represent independent indicators of risk for patients with stable coronary artery disease (CAD). Serum MDA levels were measured as thiobarbituric acid reactive substances (TBARS) in 634 patients with documented CAD using reverse-phase high-performance liquid chromatography and spectrophotometric approaches. During the three-year study, there were 51 major vascular events such as fatal/nonfatal myocardial infarction, 149 hospitalizations for nonfatal vascular events, and 139 patients underwent a major vascular procedure. At baseline, patients with TBARS levels in the highest quartile had a relative risk (RR) of 3.30 (95% confidence interval [CI] 1.47 to 7.42; p = 0.038) for major vascular events, RR of 4.10 (95% CI 2.55 to 6.60; p < 0.0001) for nonfatal vascular events, and RR of 3.84 (95% CI 2.56 to 5.76; p < 0.0001) for major vascular procedures. The effect of TBARS on events and procedures was also seen in a multivariate model adjusted for inflammatory markers (C-reactive protein, soluble intercellular adhesion molecule-1, interleukin-6), and other risk factors (age, low-density lipoprotein, high-density lipoprotein, total cholesterol, triglycerides, body mass index, and blood pressure). This analysis showed an independent effect of TBARS on major vascular events (p = 0.0149), nonfatal vascular events (p < 0.0001), major vascular procedures (p < 0.001), and all vascular events and procedures (p < 0.0001). Serum levels of TBARS were strongly predictive of cardiovascular events in patients with stable CAD, independently of traditional risk factors and inflammatory markers.

Calcium antagonists and atherosclerosis protection in hypertension.

Calcium antagonists are effective in hypertensive patients of all ethnic groups, irrespective of age, dietary salt intake, salt-sensitivity status or plasma renin activity profile. Some prospective studies show that the calcium antagonists, nifedipine GITS and nitrendipine, reduce cardiovascular morbidity and mortality at least to the same extent as the diuretics. Other prospective studies are in progress to evaluate the effect of calcium antagonists on cardiovascular morbidity and mortality, and the progression of atherosclerosis in hypertensive patients. Calcium antagonists, especially the highly lipophilic amlodipine, lacidipine and nisoldipine, are shown to possess antioxidant properties. These drugs reduce the oxidation of LDL and its influx into the arterial wall, and reduce atherosclerotic lesions in animals. Platelet production of malondialdehyde, a marker of oxygen free radical formation, is suppressed by amlodipine, lacidipine or nifedipine in hypertensive patients. New evidence from long-term clinical trials of calcium antagonists indicates that these drugs can reduce the rate of progression of atherosclerosis in hypertensive and coronary heart disease patients. In the Regression Growth Evaluation Statin Study (REGRESS), co-administration of calcium antagonist, amlodipine or nifedipine with pravasatin caused a significant reduction in the appearance of new angiographic lesions. In the Verapamil in Hypertension and Atherosclerosis Study (VHAS), verapamil was more effective than chlorthalidone in promoting regression of thicker carotid lesions in parallel with a reduction in the incidence of cardiovascular events. In the Prospective Randomized Evaluation of the Vascular Effects of Norvasc Trial (PREVENT), amlodipine slowed the progression of early coronary atherosclerosis in patients with coronary artery disease. In a subprotocol of the Intervention as a Goal in the Hypertension Treatment (INSIGHT) study, nifedipine GITS significantly decreased intima-media thickness as compared to co-amilozide (hydrochlorothiazide + amiloride). Preliminary results of the European Lacidipine Study on Atherosclerosis (ELSA) show that lacidipine reduced the intima-media thickness progression rate as compared to atenolol. Thus, selective calcium antagonists are potential antiatherosclerotic agents.

Coronary angiographic changes in patients with cardiac events in the Prospective Randomized Evaluation of the Vascular Effects of Norvasc Trial (PREVENT)

The Prospective Randomized Evaluation of the Vascular Effects of Norvasc Trial (PREVENT) was the first prospective, double-blind, randomized trial to assess specifically the antiatherosclerotic potential of a calcium antagonist in coronary artery segments with minimal, angiographic disease.1 Unanticipated reductions in prospectively defined clinical events (mainly hospitalization for unstable angina pectoris and the need for percutaneous coronary interventions [PCI]) were noted. We undertook this post hoc analysis to assess the association between angiographic findings and clinical events.

Mechanisms of atherosclerotic plaque stabilization for a lipophilic calcium antagonist amlodipine

Coronary artery disease (CAD) is the result of atherosclerosis, a vascular disorder characterized by abnormalities in vasoconstriction and endothelial function, ultimately leading to partial or complete vessel occlusion. Because the atherosclerotic plaque is marked by changes in calcium regulation, there has been interest in a potential antiatherosclerotic role for calcium antagonists. In support of this hypothesis, a recent clinical study demonstrated in patients with CAD that treatment with the lipophilic dihydropyridine-type calcium antagonist amlodipine resulted in significantly fewer cardiovascular procedures and events. The Prospective Randomized Evaluation of the Vascular Effects of Norvasc Trial (PREVENT) evaluated the effects of amlodipine on the development and progression of atherosclerotic lesions in coronary and carotid arteries in 825 patients with documented CAD. The results of PREVENT showed that patients receiving amlodipine had marked reductions in hospitalization for revascularization and unstable angina compared with placebo in a population consisting of either normotensive or controlled hypertensive patients. Ultrasound approaches determined that amlodipine therapy was also associated with significant slowing in carotid atherosclerosis—an important surrogate marker for CAD—over the 3-year period. This vascular-wall benefit associated with amlodipine treatment was not related to changes in blood pressure. The findings from PREVENT were consistent with a second reported study known as the Coronary Angioplasty Amlodipine Restenosis Study (CAPARES). These clinical results have led to an interest in potential plaque-stabilization properties of this lipophilic calcium antagonist. In this article, cellular and molecular mechanisms of action that may contribute to a beneficial role for a calcium antagonist in the treatment of atherosclerosis will be reviewed.

Confusing Press Releases and the PREVENT Study

To the Editor: The Prospective Randomized Evaluation of the Vascular Effects of Norvasc Trial (PREVENT) was presented at the American Heart Association meeting >2 years before its publication.1 At that time, a lot of confusion and uncertainty was created by the press releases. Some authors stated, “In the 825-patient Prospective Randomized Evaluation of the Vascular Effects of Norvasc Trial (PREVENT), cardiovascular morbidity and mortality events were reduced by 31%. These events included heart attacks, strokes, deaths, angioplasty, bypass surgery, hospitalizations for severe angina, and heart failure.”2 Other authors seemed to disagree: “There was no difference in the overall …

Mechanisms of plaque stabilization for a charged calcium channel blocker in coronary artery disease.

Coronary artery disease (CAD) results from atherosclerosis, a systemic vascular disorder that is the leading cause of death and disability throughout much of the developed world. Because cellular changes associated with vulnerable atherosclerotic plaque are characterized by a loss of normal calcium regulation, there is strong interest in a potential antiatherosclerotic role for calcium channel blockers. This hypothesis has been supported by investigational studies conducted in well-defined cellular and animal models of atherosclerosis. In addition, several clinical studies have tested the benefit of calcium channel blockers among patients with mild-to-moderate CAD. More recent trials have shown reductions in cardiovascular events after treatment with amlodipine, a long-acting, dihydropyridine-type calcium channel blocker. The Prospective Randomized Evaluation of the Vascular Effects of Norvasc Trial (PREVENT) demonstrated that patients with documented CAD treated with amlodipine experienced marked reductions in cardiovascular events compared with patients receiving placebo. Amlodipine also was associated with significant slowing of carotid atherosclerosis, an important surrogate marker for CAD, independent of blood pressure modification. These results have renewed interest in potential plaque stabilization properties of third-generation calcium channel blockers and their possible therapeutic role in CAD.

Rationale, design, and baseline characteristics of the Prospective Randomized Evaluation of the Vascular Effects of Norvasc Trial (PREVENT)

There is increasing recognition that determinants of plaque rupture leading to overt clinical events more often result from angiographically modest, not severe, stenoses. PREVENT may provide useful insights into the means of preventing development or progression of such lesions by possibly diminishing the substrate for plaque rupture.

Role of calcium channel blocking agents in the prevention of atherosclerosis

Summary. Calcium channel blocking agents, although effective and widely used in the symptomatic therapy of hypertension and ischemic heart disease, have an uncertain effect on the development of coronary atherosclerosis, plaque rupture, and postrupture thrombosis. Both nifedipine and nicardipine have been shown to prevent the development of new coronary lesions but not the progression of existing lesions in prospective randomized angiographic studies. Verapamil, in contrast, failed to prevent the development of new coronary lesions and had no significant effect on the progression of existing lesions. Diltiazem, although not studied in patients with coronary atheroscleroses, has been shown to prevent the development of post-transplant coronary vascular disease. Despite the beneficial effects of nifedipine and nicardipine on new coronary lesion development, they have not been shown to reduce the incidence of recurrent ischemic events or mortality in the prospective randomized studies that demonstrated their effect on new coronary lesion development. A relatively new dihydropyridine calcium channel blocking agent, amlodipine, is hypothesized to prevent atherosclerosis due to its calcium channel blocking properties as well as by mechanisms independent of its calcium channel blocking properties. This agent has been selected for evaluation in the Prospective Randomized Evaluation of the Vascular Effects of Norvasc Trial (PREVENT) to explore whether the use of amlodipine over 3 years will reduce the incidence of early atherosclerotic lesions and, possibly, the progression of existing lesions in both the coronary and carotid arterial beds. Amlodipine could play an important future role in the secondary prevention of ischemic heart disease, but further study and a demonstration of a beneficial effect on recurrent ischemic events is required before any final conclusions concerning its effectiveness are reached. Cardiovasc Drugs Ther 1995;9:21-24