A controlled clinical trial to assess the effect of a calcium channel blocker on the progression of coronary atherosclerosis

Chronic Kidney Disease Progression Risk in Patients With Diabetes Mellitus Using Dihydropyridine Calcium Channel Blockers: A Nationwide, Population-Based, Propensity Score Matching Cohort Study

Background: Whether diabetes mellitus (DM) patients with chronic kidney disease (CKD) can glean individual renal benefit from dihydropyridine calcium channel blockers (DCCBs) remains to be determined. We conducted a nationwide, population-based, propensity score matching cohort study to examine the effect of DCCBs on CKD progression in DM patients with CKD.

Methods: One million individuals were randomly sampled from Taiwan’s National Health Insurance Research Database. The study cohort consisted of DM patients with CKD who used DCCBs. The comparison cohort was propensity-matched for demographic characteristics and comorbidities. The endpoint was advanced CKD or end-stage renal disease (ESRD). The Cox proportional hazards model was used to calculate the risks.

Results: In total, 9,761 DCCB users were compared with DCCB nonusers at a ratio of 1:1. DCCB users had lower risk of advanced CKD and ESRD than nonusers—with adjusted hazard ratio [aHR; 95% confidence interval (CI)] of 0.64 (0.53–0.78) and 0.59 (95% CI, 0.50–0.71) for advanced CKD and ESRD, respectively. DCCB users aged ≥65 years had the lowest incidence rates of advanced CKD and ESRD—with aHR (95% CI) of 0.47 (0.34–0.65) and 0.48 (0.35–0.65) for advanced CKD and ESRD, respectively. Finally, cumulative DCCB use for >1,100 days was associated with the lowest advanced CKD and ESRD risks [(aHR, 0.29 (95% CI, 0.19–0.44)].

Conclusion: DM patients with CKD who used DCCBs had lower risk of progression to advanced CKD and ESRD than nonusers did.

Meta-Analysis Evaluating Calcium Channel Blockers and the Risk of Peripheral Arterial Disease in Patients With Hypertension

Clinical studies have shown that calcium channel blockers (CCB) can mitigate the progression of atherosclerosis. Their role in the primary prevention of peripheral artery disease (PAD) is unclear. We conducted a meta-analysis of randomized control trials (RCT) to compare the impact of CCB on the incidence of PAD in patients with hypertension. A comprehensive review of the literature was performed in PubMed and Cochrane registry. Studies were included if they were RCT and had outcome data on PAD with a follow-up duration of at least 6 months. CCB formed the intervention group, whereas the control group was constituted by either placebo or active treatment with any of the other antihypertensive medications. A random-effects meta-analysis was performed, and we report odds ratio as a measure of treatment effect. Our search identified 934 trials, of which 7 RCTs with 71,971 patients fulfilled the inclusion criteria. The mean duration of follow-up was 3.8 years. In patients receiving CCB, PAD events occurred in 547 out of 27,502 patients (2%) compared with 1,263 out of 42,659 patients in the control group (3%). Based on the random-effect model, the odds for development of PAD in hypertensive patients treated with CCB compared with the control group was 0.70 (95% confidence interval of 0.58 to 0.86, p = 0.0005). In conclusion, this meta-analysis of RCTs of hypertensive patients, we found that treatment with CCB was strongly associated with a decrease in the PAD compared with other antihypertensive agents or placebo.

Pharmacological and Nutritional Modulation of Vascular Calcification

Vascular calcification is an independent predictor of cardiovascular disease, and therefore, inhibition or regression of this processes is of clinical importance. The standard care regarding prevention and treatment of cardiovascular disease at this moment mainly depends on drug therapy. In animal and preclinical studies, various forms of cardiovascular drug therapy seem to have a positive effect on vascular calcification. In particular, calcium channel blockers and inhibitors of the renin-angiotensin-aldosteron system slowed down arterial calcification in experimental animals. In humans, the results of trials with these drugs are far less pronounced and often contradictory. There is limited evidence that the development of new atherosclerotic lesions may be retarded in patients with coronary artery disease, but existing lesions can hardly be influenced. Although statin therapy has a proven role in the prevention and treatment of cardiovascular morbidity and mortality, it is associated with both regression and acceleration of the vascular calcification process. Recently, nutritional supplements have been recognized as a potential tool to reduce calcification. This is particularly true for vitamin K, which acts as an inhibitor of vascular calcification. In addition to vitamin K, other dietary supplements may also modulate vascular function. In this narrative review, we discuss the current state of knowledge regarding the pharmacological and nutritional possibilities to prevent the development and progression of vascular calcification.

Approach to a successful selection of antihypertensive drugs for the patient with atherosclerosis

Coronary heart disease has become a medical and public health issue associated with multiple risk factors such as age, diet, and sedentary life style. Associations between hypertension and atherosclerosis have been extensively studied, and several trials have demonstrated antiatherosclerotic properties in some of the most widely used antihypertensive agents. Hence, calcium channel blockers, angiotensin-converting enzyme inhibitors, and angiotensin receptor blockers have been the target for a number of controlled randomized trials studying its effect on atherosclerosis progression. Carotid intima-media thickness measurement by ultrasound is used as surrogate of atherosclerosis in most of these controlled trials. This review of the literature aims to summarize the most significant controlled trials involving antihypertensive therapy and atherosclerosis regression based on the carotid intima-media thickness measurement.

eNOS-dependent antisenscence effect of a calcium channel blocker in human endothelial cells

Senescence of vascular endothelial cells is an important contributor to the pathogenesis of age-associated vascular disorders such as atherosclerosis. We investigated the effects of antihypertensive agents on high glucose-induced cellular senescence in human umbilical venous endothelial cells (HUVECs). Exposure of HUVECs to high glucose (22 mM) for 3 days increased senescence-associated- β-galactosidase (SA-β-gal) activity, a senescence marker, and decreased telomerase activity, a replicative senescence marker. The calcium channel blocker nifedipine, but not the β₁-adrenergic blocking agent atenolol or the angiotensin-converting enzyme inhibitor perindopril, reduced SA-β-gal positive cells and prevented a decrease in telomerase activity in a high-glucose environment. This beneficial effect of nifedipine was associated with reduced reactive oxygen species (ROS) and increased endothelial nitric oxide synthase (eNOS) activity. Thus, nifedipine prevented high glucose-induced ROS generation and increased basal eNOS phosphorylation level at Ser-1177. Treatment with N^G-nitro-L-arginine (L-NAME) and transfection of small interfering RNA (siRNA) targeting eNOS eliminated the anti-senscence effect of nifedipine. These results demonstrate that nifedipine can prevent endothelial cell senescence in an eNOS-dependent manner. The anti-senescence action of nifedipine may represent a novel mechanism by which it protects against atherosclerosis.

Amlodipine reduces AngII-induced aortic aneurysms and atherosclerosis in hypercholesterolemic mice

Background

The purpose of this study was to determine effects of amlodipine, a dihydropyridine calcium channel blocker, on development of angiotensin II (AngII)-induced vascular pathologies.

Methods and Results

Male LDL receptor -/- mice were infused with vehicle, amlodipine (5 mg/kg/d), AngII (1,000 ng/kg/min), or AngII + amlodipine for 4 weeks through osmotic pumps (n=10/group). Mice were fed a saturated fat-enriched diet for 1 week prior to pump implantation and during 4 weeks of infusion. Infusion of amlodipine resulted in plasma concentrations of 32 ± 2 ng/ml and 27 ± 2 ng/ml for mice in saline + amlodipine and AngII + amlodipine groups, respectively. This infusion rate of amlodipine did not affect AngII-induced increases in systolic blood pressure. Three of 10 (30%) mice infused with AngII died of aortic rupture, while aortic rupture did not occur in mice co-infused with AngII + amlodipine. Suprarenal aortic width and intimal area of ascending aortas were measured to define aortic aneurysms. In the absence of AngII infusion, amlodipine did not change suprarenal aortic width and ascending aortic area. Infusion of AngII led to profound increases of suprarenal aortic width (saline + vehicle versus AngII + vehicle: 0.86 ± 0.02 versus 1.72 ± 0.26 mm; P=0.0006), whereas co-infusion of AngII and amlodipine diminished abdominal dilation (1.02 ± 0.14 mm; P=0.003). As expected, AngII infusion increased mean intimal area of ascending aortas (saline + vehicle versus AngII + vehicle: 8.5 ± 0.3 versus 12.5 ± 1.1 mm²; P=0.001), while co-infusion of AngII and amlodipine ablated dilation of the ascending aorta (8.6 ± 0.2 mm²; P=0.03). Co-administration of amlodipine also significantly attenuated AngII-induced atherosclerosis in the thoracic region as quantified by percent lesion area (AngII + vehicle versus AngII + amlodipine: 5.8 ± 2.1 % versus 0.3 ± 0.1%; P=0.05).

Conclusions

Amlodipine inhibited AngII-induced aortic aneurysms in both the abdominal and ascending regions, and atherosclerosis in hypercholesterolemic mice.

Calcium channel blockers prevent endothelial cell activation in response to necrotic trophoblast debris: possible relevance to pre-eclampsia

AIMS

Pre-eclampsia is characterized by endothelial activation, which is triggered by placental factor(s). One such factor may be trophoblastic debris that is shed into the maternal blood to become trapped against the maternal pulmonary endothelium. Phagocytosis of necrotic trophoblastic debris (NTD) induces endothelial cell activation with increased secretion of interleukin-6 (IL-6) and transforming growth factor β1 (TGFβ1), which may induce systemic endothelial cell activation. In addition to its effects on vascular smooth muscle, evidence suggests that nifedipine may also affect the endothelium, contributing to the therapeutic benefits of the drug. We investigated whether nifedipine could reverse the endothelial cell activation induced by NTD.

METHODS AND RESULTS

Trophoblastic debris was collected from placental explants and exposed to endothelial cells with or without nifedipine, verapamil, or a nitric oxide (NO) donor for 24 h. Endothelial cell activation was measured by cell-surface intracellular adhesion molecule-1 and E-selectin, as well as monocyte adhesion. The activation of endothelial cells exposed to NTD or sera from pre-eclamptic women was significantly reduced by nifedipine or verapamil. In addition, the increases in the levels of IL-6 or TGFβ1 in conditioned media from endothelial cells following phagocytosis of NTD were significantly reduced by nifedipine. These actions of nifedipine were reversed by the NO synthetase inhibitor l-NAME and mimicked by a NO donor.

CONCLUSION

Our results suggest that calcium channel blockers may have a direct effect upon endothelial cells, reducing the endothelial cell activation that is a key pathogenic feature of pre-eclampsia. This action may be mediated, in part, by NO.

Diagnostic performance of noninvasive myocardial perfusion imaging using single-photon emission computed tomography, cardiac magnetic resonance, and positron emission tomography imaging for the detection of obstructive coronary artery disease: a meta-analysis

OBJECTIVES

This study aimed to determine the diagnostic accuracy of the 3 most commonly used noninvasive myocardial perfusion imaging modalities, single-photon emission computed tomography (SPECT), cardiac magnetic resonance (CMR), and positron emission tomography (PET) perfusion imaging for the diagnosis of obstructive coronary artery disease (CAD). Additionally, the effect of test and study characteristics was explored.

BACKGROUND

Accurate detection of obstructive CAD is important for effective therapy. Noninvasive myocardial perfusion imaging is increasingly being applied to gauge the severity of CAD.

METHODS

Studies published between 1990 and 2010 identified by PubMed search and citation tracking were examined. A study was included if a perfusion imaging modality was used as a diagnostic test for the detection of obstructive CAD and coronary angiography as the reference standard (≥50% diameter stenosis).

RESULTS

Of the 3,635 citations, 166 articles (n = 17,901) met the inclusion criteria: 114 SPECT, 37 CMR, and 15 PET articles. There were not enough publications on other perfusion techniques such as perfusion echocardiography and computed tomography to include these modalities into the study. The patient-based analysis per imaging modality demonstrated a pooled sensitivity of 88% (95% confidence interval [CI]: 88% to 89%), 89% (95% CI: 88% to 91%), and 84% (95% CI: 81% to 87%) for SPECT, CMR, and PET, respectively; with a pooled specificity of 61% (95% CI: 59% to 62%), 76% (95% CI: 73% to 78%), and 81% (95% CI: 74% to 87%). This resulted in a pooled diagnostic odds ratio (DOR) of 15.31 (95% CI: 12.66 to 18.52; I(2) 63.6%), 26.42 (95% CI: 17.69 to 39.47; I(2) 58.3%), and 36.47 (95% CI: 21.48 to 61.92; I(2) 0%). Most of the evaluated test and study characteristics did not affect the ranking of diagnostic performances.

CONCLUSIONS

SPECT, CMR, and PET all yielded a high sensitivity, while a broad range of specificity was observed. SPECT is widely available and most extensively validated; PET achieved the highest diagnostic performance; CMR may provide an alternative without ionizing radiation and a similar diagnostic accuracy as PET. We suggest that referring physicians consider these findings in the context of local expertise and infrastructure.

Assessment of cardiac ischaemia and viability: role of cardiovascular magnetic resonance

Over the past years, cardiovascular magnetic resonance (CMR) has proven its efficacy in large clinical trials, and consequently, the assessment of function, viability, and ischaemia by CMR is now an integrated part of the diagnostic armamentarium in cardiology. By combining these CMR applications, coronary artery disease (CAD) can be detected in its early stages and this allows for interventions with the goal to reduce complications of CAD such as infarcts and subsequently chronic heart failure (CHF). As the CMR examinations are robust and reproducible and do not expose patients to radiation, they are ideally suited for repetitive studies without harm to the patients. Since CAD is a chronic disease, the option to monitor CAD regularly by CMR over many decades is highly valuable. Cardiovascular magnetic resonance also progressed recently in the setting of acute coronary syndromes. In this situation, CMR allows for important differential diagnoses. Cardiovascular magnetic resonance also delineates precisely the different tissue components in acute myocardial infarction such as necrosis, microvascular obstruction (MVO), haemorrhage, and oedema, i.e. area at risk. With these features, CMR might also become the preferred tool to investigate novel treatment strategies in clinical research. Finally, in CHF patients, the versatility of CMR to assess function, flow, perfusion, and viability and to characterize tissue is helpful to narrow the differential diagnosis and to monitor treatment.

Calcium channel blocker nilvadipine, but not diltiazem, inhibits ocular inflammation in endotoxin-induced uveitis

PURPOSE

Calcium channel blockers (CCBs), widely used for hypertensive patients, have recently been shown to inhibit atherosclerosis by their antioxidative action. The aim of the present study was to examine whether the CCBs nilvadipine and diltiazem reduce ocular inflammation in endotoxin-induced uveitis (EIU).

METHODS

EIU was induced in male C57/B6 mice with a single intraperitoneal injection of lipopolysaccharide (LPS). The animals received intraperitoneal injections of either nilvadipine, diltiazem, or vehicle for 5 days before the LPS application. Twenty-four hours after EIU induction, adherent leukocytes to the retinal vasculature were counted with a concanavalin A lectin perfusion-labeling technique. The protein concentration in the aqueous humor was measured to assess blood-ocular barrier breakdown. Retinal levels of intercellular adhesion molecule (ICAM)-1 and monocyte chemotactic protein (MCP)-1 were analyzed by enzyme-linked immunosorbent assay. LPS-stimulated generation of superoxide in murine microvascular endothelial cells was examined with a nitroblue tetrazolium assay.

RESULTS

Compared to vehicle treatment, application of nilvadipine, but not diltiazem, led to significant suppression of EIU-associated retinal leukocyte adhesion, together with anterior-chamber protein leakage, retinal expression of ICAM-1 and MCP-1, and LPS-induced superoxide generation in vitro.

CONCLUSIONS

The CCB nilvadipine exercises an inhibitory effect on the pathogenesis of ocular inflammation through the suppression of inflammation-related molecules.

Impact of medical therapy on atheroma volume measured by different cardiovascular imaging modalities

Atherosclerosis is a systemic disease that affects most vascular beds. The gold standard of atherosclerosis imaging has been invasive intravascular ultrasound (IVUS). Newer noninvasive imaging modalities like B-mode ultrasound, cardiac computed tomography (CT), positron emission tomography (PET), and magnetic resonance imaging (MRI) have been used to assess these vascular territories with high accuracy and reproducibility. These imaging modalities have lately been used for the assessment of the atherosclerotic plaque and the response of its volume to several medical therapies used in the treatment of patients with cardiovascular disease. To study the impact of these medications on atheroma volume progression or regression, imaging modalities have been used on a serial basis providing a unique opportunity to monitor the effect these antiatherosclerotic strategies exert on plaque burden. As a result, studies incorporating serial IVUS imaging, quantitative coronary angiography (QCA), B-mode ultrasound, electron beam computed tomography (EBCT), and dynamic contrast-enhanced magnetic resonance imaging have all been used to evaluate the impact of therapeutic strategies that modify cholesterol and blood pressure on the progression/regression of atherosclerotic plaque. In this review, we intend to summarize the impact of different therapies aimed at halting the progression or even result in regression of atherosclerotic cardiovascular disease evaluated by different imaging modalities.

Future strategies in the management of coronary artery disease

New diagnostic techniques have now become available that will enable us to obtain information on coronary artery disease (CAD), which was not previously possible. This is urgently needed, since changes in CAD management are highly desirable considering that up to 60% of patients die due to an insufficient diagnostic strategy (reactive strategy). In this article, the pathophysiology of CAD and the evidence of current concepts on coronary atherosclerosis are critically reviewed. Consequently, a shift from a 'reactive strategy' of CAD management to an active strategy is proposed in order to detect and treat patients before acute myocardial infarcts occur. Reliability, repeatability, cost-effectiveness and comfort are important features of an optimal test for this active strategy. This perspective gives an overview of current and future tests with respect to these features. The novel tomographic techniques are particularly promising with respect to standardization and reproducibility, which will set the basis for the determination of test performance and, consequently, cost-effectiveness. Assessment of cost-effectiveness is increasingly important, since prevalence of CAD is high and will most likely increase, while resources will remain restricted in most countries. Considering these economic restrictions, this article also proposes new mathematical tools using data from prospective trials and large international registries as an objective means to select the best tests for CAD diagnosis and management, and to identify those patient subsets which benefit most from an active strategy.

End organ protection by calcium-channel blockers

In recent years, much attention has been given to end organ protection by antihypertensive, anti-heart failure, and anti-ischemic medications. This review describes the available information on end organ protection by calcium-channel blockers (CCBs). In normotensive patients and patients with hypertension treated with long-acting dihydropyridines, medial thickness was thinner than in patients treated with atenolol or in untreated hypertensive patients. Long-term treatment was associated with significant reduction in left ventricular mass. Calcium-channel blockers also improved endothelial-dependent relaxation and reversed the vasoconstrictive response to nitric oxide inhibitors. In diabetic patients, CCBs were effective in preserving kidney function and microalbuminurea. The combination of angiotensin-converting enzyme (ACE) inhibitors and CCBs was more effective than ACE inhibitors alone in preserving kidney function. In animal experiments, CCBs prevented development of coronary atheroschlerosis; however, in humans only limited data are available on their antiatherogenic effect. Some studies suggest that CCBs exert antiplatelets properties and may therefore be beneficial in patients with coronary artery disease.

Calcium channel regulation in vascular smooth muscle cells: synergistic effects of statins and calcium channel blockers

In the Anglo-Scandinavian Cardiac Outcomes Trial-Lipid Lowering Arm (ASCOT-LLA) we have reported a positive interaction between atorvastatin and amlodipine-based antihypertensive strategy in terms of the prevention of coronary events. In cellular and molecular studies on human vascular smooth muscle cells (VSMC) we have reported that transformation from a differentiated to a synthetic or dedifferentiated phenotype is associated with loss of function of L-type calcium channels and hence loss of potential responsiveness to calcium channel blockers (CCB). Statins directly inhibit cell cycle progression and dedifferentiation of VSMC due to their ability to inhibit the synthesis of isoprenoid cholesterol intermediates. We hypothesize that statins promote a more differentiated VSMC phenotype that results in upregulation of L-type calcium channels and restoration of a CCB-sensitive calcium influx pathway in VSMC, favourably affecting the balance that exists between VSMC proliferation, apoptosis and matrix metalloproteinase production with an associated increase in stability of atheromatous plaques.

Modulation of arterial reactivity using amlodipine and atorvastatin measured by ultrasound examination (MARGAUX)

OBJECTIVE

To evaluate the effect of the calcium channel blocker amlodipine on endothelial function in normotensive patients with coronary disease taking concomitant atorvastatin therapy.

METHODS AND RESULTS

Atorvastatin was titrated (10-80 mg/day) to maintain LDL-C<2.5 mmol/L and patients were randomized to receive amlodipine (5-10mg/day, n=64) or placebo (n=70) for 12 months. Brachial artery flow-mediated vasodilation (FMD) was assessed using vascular ultrasound. Inflammatory markers were also measured. At 12 months there was a significant decrease in mean low-density lipoprotein cholesterol (LDL-C) (4.4-2.1 mmol/L, P<0.0001), high-sensitivity C-reactive protein (hsCRP) (3.8-2.3mg/L, P<0.0001) and soluble vascular cell adhesion molecule-1 (sVCAM-1) (710-665 ng/mL, P<0.0001) for all patients, compared with baseline. Amlodipine was associated with a mean blood pressure reduction of 8/3 mm Hg (P<0.0001) whereas patients on placebo had no significant change. In the atorvastatin-placebo group, mean FMD increased (7.3-9.5%, P<0.05) with no change in nitroglycerin-mediated dilation. No further benefit on FMD or inflammatory markers was observed with the addition of amlodipine.

CONCLUSIONS

Intensive reduction of LDL-C with atorvastatin improves endothelium-dependent vasodilation and reduces markers of inflammation in patients with coronary disease. Amlodipine was not associated with a significant additional benefit on these variables.

Modulation of calcification of vascular smooth muscle cells in culture by calcium antagonists, statins, and their combination

Background Vascular calcification is an organized process in which vascular smooth muscle cells (VSMCs) are implicated primarily. The purpose of the present study was to assess the effects of calcium antagonists and statins on VSMC calcification in vitro. Methods VSMC calcification was stimulated by incubation in growth medium supplemented with 10 mmol/l β-glycerophosphate, 8 mmol/l CaCl₂, 10 mmol/l sodium pyruvate, 1 μmol/l insulin, 50 μg/ml ascorbic acid, and 100 nmol/l dexamethasone (calcification medium). Calcification, proliferation, and apoptosis of VSMCs were quantified. Results Calcium deposition was stimulated dose-dependently by β-glycerophosphate, CaCl₂, and ascorbic acid (all P < 0.01). Addition of amlodipine (0.01–1 μmol/l) to the calcification medium did not affect VSMC calcification. However, atorvastatin (2–50 μmol/l) stimulated calcium deposition dose-dependently. Combining treatments stimulated calcification to a degree similar to that observed with atorvastatin alone. Both atorvastatin and amlodipine inhibited VSMC proliferation at the highest concentration used. Only atorvastatin (50 μmol/l) induced considerable apoptosis of VSMCs. Conclusion In vitro calcification of VSMCs is not affected by amlodipine, but is stimulated by atorvastatin at concentrations ≥10 μmol/l, which could contribute to the plaque-stabilizing effect reported for statins.

A double-blind, controlled, multicenter, randomized study comparing the antihypertensive effectiveness and tolerance of a daily dose of two nifedipine formulations: nifedipine microgranules versus nifedipine osmotic pump

INTRODUCTION

Controlled clinical studies have clearly established the advantages of blood pressure (BP) reduction. However, optimal control of BP in the population is still not adequate. Monotherapy is ineffective in the majority of hypertensive patients, and multidrug therapy increases costs.

OBJECTIVE

The objective of the study was to assess to what extent and how uniformly BP can be controlled with two different 24-hour drug-releasing formulations of nifedipine, used as monotherapy.

METHODS

One hundred ninety-two patients of both genders, aged 18 to 65 years, with mild to moderate (Stage 1 and 2) essential hypertension with systolic BP <200 mm Hg and diastolic BP between 90 and 115 mm Hg were randomized in a double-blind, double-dummy fashion to receive sustained-release formulations of 30 mg nifedipine/day either as microgranules (NMG) or via osmotic pump (NOP) for 8 weeks. Office BP was measured at baseline (after 2 weeks of placebo) and after the third to fourth week of treatment. If at the third to fourth week the systolic BP/diastolic BP did not reach values of <140/<90 mm Hg, the dose was doubled to 60 mg/day. Monotherapy that did not yield these BP values at 8 weeks was considered a failure. Ambulatory monitoring of blood pressure (AMBP) was also performed after the placebo period and at the end of treatment. Smoothness index (SI) and trough/peak ratio (T/P) were calculated and their correlation was checked.

RESULTS

The initial systolic/diastolic BP values were similar at baseline and decreased significantly after the third to fourth week of treatment, with no difference between the groups. The proportions of patients reaching the goal BP (<140/<90 mm Hg) were similar in the two groups: NMG, 71%, and NOP, 78% (P = 0.12). There were no changes in the heart rate in either group. There was no difference between groups in the reduction in mean arterial pressure measured by AMBP. The frequency of SI values >1.4 and T/P ratios of >0.5 was similar in both groups. An important correlation was found between the SI and T/P values. The incidence of adverse effects was low and similar in both groups.

CONCLUSIONS

Target BP was reached in more than 70% of patients receiving monotherapy with either formulation. Both formulations were tolerated well.

Myocardial perfusion

Noninvasive cardiac magnetic resonance (CMR) imaging has progressed rapidly over the past few years and will most likely become an integral part of the diagnostic workup of patients with known or suspected coronary artery disease (CAD). In this article the rationale for using perfusion-CMR is discussed, followed by a summary of current state-of-the-art perfusion-CMR techniques that addresses pharmacological stress, monitoring, pulse sequences, and doses of contrast media (CM) for first-pass studies. In the second part, unresolved aspects of perfusion-CMR, such as the lack of fully established and validated imaging protocols, are discussed. The optimum pulse sequence parameters, required cardiac coverage, analysis algorithms, criteria for data quality, and other aspects remain to be defined. Furthermore, since expertise in perfusion-CMR is not yet widely available, training of physicians and technicians to perform perfusion-CMR according to recognized standards is an important future requirement. In the last part of the review, some ideas are proposed to improve the management of patients with known or suspected CAD. This involves making a shift from a "reactive" strategy, in which patients are typically approached when they are symptomatic, to an "active" strategy, in which perfusion-CMR is performed for early detection of high-risk patients so that revascularizations can be performed before potentially deadly infarcts occur. An ideal test for such an active strategy would be highly accurate, reliable, safe (and thus repeatable), and affordable. Large multicenter trials have shown that in experienced centers perfusion-CMR is reliable and repeatable, and it is hoped that future studies will demonstrate its cost-effectiveness as well.

Differential effects of AT1 receptor and Ca2+ channel blockade on atherosclerosis, inflammatory gene expression, and production of reactive oxygen species

Angiotensin II receptor blockade has been shown to inhibit atherosclerosis in several different animal models. We sought to determine if this effect was the result of blood pressure reduction per se or a result of the anti-inflammatory effects of receptor blockade. ApoE-deficient mice were fed a high fat diet and treated with either an angiotensin II receptor antagonist, candesartan (0.5 mg/kg/day, s.c.) or a calcium channel blocker, amlodipine (7.5 mg/kg/day, mixed with food). Atherosclerotic lesion area, aortic inflammatory gene expression as well as aortic H2O2 and superoxide production were assayed. We found that candesartan but not amlodipine treatment dramatically attenuated the development of atherosclerosis despite a similar reduction in blood pressure. Similarly, candesartan treatment inhibited aortic expression of inflammatory genes and production of reactive oxygen species, effects not seen with amlodipine. These data demonstrate that angiotensin II receptor blockade inhibits atherosclerosis by reducing vascular oxidative stress and inflammatory gene production independent of blood pressure reduction.

Tracking Coronary Calcification and Atherosclerotic Lesions in Patients with Stable Angina Pectoris Undergoing Nifedipine Therapy

AIMS

The objective of the Coronary Calcification (CC) study was to determine in patients with chronic symptomatic coronary artery disease, if, in addition to standard therapy, nifedipine GITS, relative to placebo, would arrest or slow down the progression of calcium or the development of new atherosclerotic lesions in the coronary arteries.

METHODS AND RESULTS

The CC study was part of the ACTION trial. Multi-slice computerized tomography was used to measure and track the progression of CC. Five hundred and eighteen patients were included in this study. The changes in calcium score from baseline every 24 months, over a period of between 4.5 and 6 years, were similar in the nifedipine and placebo treatment groups (p = 0.8). Compared to placebo, more patients in the nifedipine group (71 vs. 60%) were free of new calcified atherosclerotic lesions during follow-up(p = 0.095).

CONCLUSION

Nifedipine GITS was not effective in slowing down the progression of calcium in advanced atherosclerotic plaques in patients with stable angina pectoris. Although statistically not significant, Nifedipine demonstrated a trend in slowing down the development of new atherosclerotic lesions.

Effect of nifedipine on adiponectin in hypertensive patients with type 2 diabetes mellitus

Nifedipine, a dihydropyridine calcium antagonist, improves endothelial function in patients with hypercholesterolaemia by enhancing nitric oxide (NO) activity, and increases endothelial NO bioavailability by antioxidant mechanisms. We administered a long-acting nifedipine formulation (controlled release (CR) nifedipine: 20 mg/day) to hypertensive patients for 6 months. There were no other changes of drug treatment during therapy with CR nifedipine. Clinical and biochemical data obtained before and after CR nifedipine administration were compared. All markers were measured by enzyme-linked immunosorbant assay. The levels of soluble markers (soluble CD40 ligand, soluble P-selectin, and soluble E-selectin), microparticles (MP) (platelet-derived MP, monocyte-derived MP, and endothelial cell-derived MP), and adiponectin differed between the control group and the hypertension group. The levels of these markers were also different in hypertensive patients with and without type 2 diabetes compared with the control group. In the hypertensive patients with type 2 diabetes, all markers except adiponectin decreased significantly after 3 months of CR nifedipine treatment. In contrast, markers were unchanged in the hypertensive patients without type 2 diabetes. Adiponectin was increased after 6 months of CR nifedipine treatment in hypertensive patients with type 2 diabetes. The effects of CR nifedipine on platelet/monocyte activation and adiponectin levels demonstrated in the present study indicate the potential effectiveness of calcium antagonist therapy for hypertensive patients with type 2 diabetes.

Progression of coronary artery disease in non-ischemic dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is traditionally divided into ischemic and non-ischemic etiologies. We review data from clinical trials that suggest some patients in the latter subgroup develop ischemic complications including fatal myocardial infarction. However, the reasons for and magnitude of the effect are not known. Prospective screening studies and improved endpoint adjudication in clinical trials may be required to better delineate the degree to which the phenomenon occurs. Risk factor modification strategies should be applied to the non-ischemic DCM cohort, especially with continued improvements in survival rates in patients with heart failure.

Reducing the burden of cardiovascular calcification in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) have a higher burden of atherosclerotic coronary artery disease compared with age- and gender-matched individuals with normal renal function. Cardiovascular calcification (CVC), a marker of atherosclerosis, is also more prevalent in these patients and is associated with serious clinical consequences. The pathogenesis of CVC is complex and includes factors that promote calcification and others that inhibit calcification. Thus, multiple therapeutic interventions should be used simultaneously to reduce the burden of calcification in patients with CKD. Thus far, interventional attempts have focused on curtailing the effects of factors that promote calcification such as management of known traditional factors for atherosclerotic coronary artery disease and on adopting specific approaches to normalize mineral metabolism, deliver adequate dialysis, and control serum cholesterol level. By contrast, interventions that may bolster the effects of inhibitors of calcification have not yet been studied well but are beginning to attract attention. Ideally, the goal of interventions is not only to slow or halt progression of calcification but also to reverse pre-existing calcification. Whether this goal is achievable is not currently known. This review examines the potential of various therapeutic interventions in reducing the CVC burden in patients with CKD. Moreover, the review is intended to stimulate more research in this area because the efficacy of these interventions has not been examined in controlled clinical trials.

Anti-Atherosclerotic Effect of Amlodipine, Alone and in Combination With Atorvastatin, in APOE*3-Leiden/hCRP Transgenic Mice

We investigated the pleiotropic effects of a calcium antagonist (amlodipine) on early atherosclerosis development in the presence and absence of an HMG-CoA-reductase inhibitor (atorvastatin) in apolipoprotein E*3-Leiden/human C-reactive protein (E3L/CRP) transgenic mice. Male E3L/CRP transgenic mice were fed a cholesterol-containing diet either with or without amlodipine and/or atorvastatin. After 31 weeks, atherosclerosis in the aortic root area was quantified. Treatment with amlodipine did not significantly lower blood pressure, but resulted in a 43% reduction (P < 0.03) of lesion area as compared with the untreated group. Treatment with atorvastatin resulted in an 80% reduction of lesion area as compared with the untreated group (P < 0.001). Combined treatment with amlodipine and atorvastatin decreased the lesion area by 93%, significantly more than either treatment alone (P < 0.008). Plasma C-reactive protein levels were mildly elevated, on average 10 +/- 6 mg/L, and did not differ between groups, neither on baseline nor during treatment. Treatment with amlodipine, independently of blood pressure lowering, reduced atherosclerosis development in E3L/CRP mice. Atorvastatin had a strong anti-atherosclerotic effect, whereas co-treatment with amlodipine enhanced this effect significantly. Plasma C-reactive protein levels were not affected by any of the three treatments.

Divergent action of calcium channel blockers on ATP-binding cassette protein expression

Calcium channel blockers (CCBs) are widely used in clinical practice, and have been reported to be effective in preventing the progression of atherosclerosis. We examined whether various types of calcium channel blockers affected the expression of ATP binding cassette transporter A1 (ABCA1), a factor contributing to anti-atherogenesis. Undifferentiated monocytic cell line, THP-1 cells were maintained in RPMI 1640 medium and treated with different kinds of calcium channel blockers. Among the calcium channel blockers tested, aranidipine and efonidipine increased ABCA1 protein expression without an increase in ABCA1 mRNA expression, whereas other calcium channel blockers (eg, nifedipine, amlodipine, and nicardipine) or T-type calcium channel blockers (eg, mibefradil and nickel chloride) failed to upregulate ABCA1 expression. H89, a protein kinase A inhibitor inhibited the aranidipine-induced ABCA1 protein expression, whereas genistein (a tyrosine kinase inhibitor), or AG490 (a JAK-2 inhibitor) had no effects. Neither of these inhibitors suppressed the efonidipine-induced ABCA1 protein expression. Intracellular cAMP levels were elevated only by aranidipine, but not by efonidipine. In conclusion, aranidipine and efonidipine have the ability to induce ABCA1 protein by distinct mechanisms; protein kinase A is involved in the aranidipine-induced ABCA1 upregulation. This non-class effect of calcium channel blockers may potentially offer beneficial action in the treatment of hypertensive subjects with atherosclerosis.

Nifedipine enhances the cardioprotective effect of an angiotensin-II receptor blocker in an experimental animal model of heart failure

This study was designed to examine the hypothesis that a calcium channel blocker nifedipine (CCB) could enhance the cardioprotective effect of an angiotensin-ll receptor blocker candesartan (ARB) in the treatment for heart failure. Isoproterenol (ISP) was injected into male rats at 300 mg/kg to produce progressive heart failure. Three months later, the rats were divided into 4 groups and treated for 4 weeks with 1) vehicle (n = 20), 2) ARB at 0.2 mg/kg/day (n = 6), 3) CCB at 10 mg/kg/day (n = 6), or 4) both drugs (n = 8). Rats injected with saline served as controls (n = 13). ISP caused severe myocardial degeneration and decreased the capillary density (D(cap)) of the left ventricular (LV) myocardium (mean +/- SD: 2,197 +/- 627 vs. 2,847 +/- 298 N/mm2 for normal controls), while increasing plasma thiobarbituric acid-reactive substances (TBARS; 3.6 +/- 1.1 vs. 1.9 +/- 0.5 nmol/ml). Although ARB therapy preserved cardiac morphology, it had little effect on D(cap) or oxidative stress. On the other hand, CCB decreased plasma TBARS and 4-hydroxy-2-nonenal protein expression in LV myocardium. Furthermore, the combination of CCB and ARB increased D(cap) and preserved the ultrastructure of LV myocardium, so this combination may be a useful option for the treatment of heart failure.

Long-term treatment with nifedipine modulates procoagulant marker and C-C chemokine in hypertensive patients with type 2 diabetes mellitus

In type 2 diabetes mellitus, there is increased risk of nephropathy and cardiovascular complications and the incidence of renal failure increases in advanced stages of the disease. Nifedipine, a dihydropyridine-type calcium antagonist, improves endothelial function in hypercholesterolemia by enhancing nitric oxide function, and increases endothelial nitric oxide bioavailability by antioxidative mechanisms. We administered nifedipine, 50 mg/day, to the hypertensive patients for 12 months. There were no other changes in any of the patient's pharmacologic regimen during nifedipine treatment. Clinical and biochemical data obtained before and after nifedipine administration were compared. All markers were measured by ELISA. The levels of platelet activation markers (CD62P, CD63, PAC-1, and Annexin V), microparticles (PDMP and MDMP), RANTES and soluble adhesion markers (sP-selectin and sVCAM-1) differed in the control group and the hypertension group. The levels of these markers were also different in hypertensive patients with and without type 2 diabetes but were unchanged in patients without diabetes in comparison to the control group. However, the concentrations of MDMPs, chemokines, and soluble adhesion markers in hypertensive patients without type 2 diabetes decreased significantly following nifedipine treatment, although the level of RANTES was unchanged. Systolic blood pressure correlated with CD62P, CD63, annexin V, and RANTES levels, and diastolic blood pressure with CD62P and annexin V levels. The effect of nifedipine on platelet activation markers and C-C chemokines in the present study indicates potential effectiveness of calcium antagonist therapy for hypertensive patients with type 2 diabetes.

Different antioxidative potencies of dihydropyridine calcium channel modulators in various models

There is evidence that dihydropyridine calcium antagonists (DHP) play a beneficial role during the development of atherosclerosis. Since antioxidative properties of this substance class may be important, we investigated the antioxidative potency of the DHP prototype calcium channel antagonist nifedipine, the long acting calcium channel antagonist lacidipine, the DHP calcium channel agonist Bay K 8644 and the bulky DHP derivate Bay O 5572 (negligible effects on L-type calcium channels) in three different models. Additionally, we examined the potential correlation between lipophilic and antioxidative properties. In an in vitro model, Bay K 8644 was significantly more effective in scavenging superoxide anions (hypoxanthine/xanthine-oxidase-assay) than lacidipine, Bay O 5572 or nifedipine (micro- to millimolar concentration range). Addition of artificial membrane preparations (dimyristoylphosphatidylcholine) to mimic a physiological environment resulted in an enhanced antioxidative effect, with lacidipine being the most effective DHP to quench radicals (low micromolar concentration range). Thirdly, in a more physiological model of hyperglycemia (30 mmol/l) induced release of reactive oxygen species (ROS) from native endothelial cells of porcine coronary arteries, we showed that nifedipine was a significantly more potent antioxidant (therapeutical nanomolar concentration range) than the other DHP. Calculation of the lipophilicity of the four substances (lacidipine>Bay O 5572>Bay K 8644>nifedipine) showed a positive correlation between the antioxidative potency and the lipophilicity in the model with the artificial membranes but not in the other models. We conclude that it seems necessary to access antioxidative properties of substances in physiological models in which we could demonstrate that nifedipine exhibits ROS-quenching properties in a therapeutic concentration range.

Selecting antihypertensive drug therapy: the JNC-V controversy

OBJECTIVE

To present both the supporting and the opposing arguments for the fifth set of recommendations issued by the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure (JNC).

METHODS

The published studies are reviewed, and the various opinions are discussed.

RESULTS

The 1993 recommendation from the JNC that diuretics or beta-adrenergic blockers be preferred for therapy in most patients with hypertension has proved controversial. This recommendation derived primarily from recent long-term studies showing convincing reductions in cardiovascular morbidity and mortality when these agents are used to control hypertension. Comparable data have not yet been obtained for newer agents, such as calcium channel blockers and angiotensin-converting enzyme inhibitors. Nonetheless, some critics of the JNC recommendation still favor the newer agents because of their putatively superior side-effect profile, from both a metabolic and a compliance standpoint.

CONCLUSION

The issue of optimal antihypertensive drug therapy will not be definitively resolved until long-term studies directly comparing the various classes of agents are completed in future years.

Class of Antihypertensive Drugs, Blood Pressure Status, and Risk of Cardiovascular Disease in Hypertensive Patients: A Case-Control Study in Japan

The purpose of this study was to compare the effect of different classes of antihypertensives on the risk of cardiovascular events in a case-control study of hypertensive patients. The subjects consisted of 171 hypertensive patients who had experienced a cardiovascular event and 537 randomly selected hypertensive controls who were matched to the cases by gender, age, and hospital/clinic. Both cases and controls had been under antihypertensive medication for at least 6 months before the onset of the cardiovascular event (cases) or before the enrollment (controls). A total of 134 physicians across the nation recruited cases and controls, and reported details of the prescription of antihypertensives and clinical and behavioral variables of their patients. Although there was no measurable difference in the risk of cardiovascular events according to the class of antihypertensives, statistically significant increases in the risk of cardiovascular events were observed for non-use of calcium antagonists among patients with angina pectoris and for non-use of the renin-angiotensin system inhibitor (angiotensin-converting enzyme inhibitor and angiotensin II receptor blockers combined) among patients with diabetes mellitus. Higher levels of blood pressure were associated with an increased risk of cardiovascular events. The findings suggest that appropriate control of blood pressure is more important in the treatment of hypertension than the choice of antihypertensives.

Calcium antagonists

Calcium antagonists were introduced for the treatment of hypertension in the 1980s. Their use was subsequently expanded to additional disorders, such as angina pectoris, paroxysmal supraventricular tachycardias, hypertrophic cardiomyopathy, Raynaud phenomenon, pulmonary hypertension, diffuse esophageal spasms, and migraine. Calcium antagonists as a group are heterogeneous and include 3 main classes--phenylalkylamines, benzothiazepines, and dihydropyridines--that differ in their molecular structure, sites and modes of action, and effects on various other cardiovascular functions. Calcium antagonists lower blood pressure mainly through vasodilation and reduction of peripheral resistance. They maintain blood flow to vital organs, and are safe in patients with renal impairment. Unlike diuretics and beta-blockers, calcium antagonists do not impair glucose metabolism or lipid profile and may even attenuate the development of arteriosclerotic lesions. In long-term follow-up, patients treated with calcium antagonists had development of less overt diabetes mellitus than those who were treated with diuretics and beta-blockers. Moreover, calcium antagonists are able to reduce left ventricular mass and are effective in improving anginal pain. Recent prospective randomized studies attested to the beneficial effects of calcium antagonists in hypertensive patients. In comparison with placebo, calcium antagonist-based therapy reduced major cardiovascular events and cardiovascular death significantly in elderly hypertensive patients and in diabetic patients. In several comparative studies in hypertensive patients, treatment with calcium antagonists was equally effective as treatment with diuretics, beta-blockers, or angiotensin-converting enzyme inhibitors. From these studies, it seems that a calcium antagonist-based regimen is superior to other regimens in preventing stroke, equivalent in preventing ischemic heart disease, and inferior in preventing congestive heart failure. Calcium antagonists are also safe and effective as first-line or add-on therapy in diabetic hypertensive patients. Heart rate-lowering calcium antagonists (verapamil, diltiazem) may have an edge over the dihydropyridines in post-myocardial infarction patients and in diabetic nephropathy. Thus, calcium antagonists may be safely used in the management of hypertension and angina pectoris.

Drug treatment of stable angina pectoris in the elderly: defining the place of calcium channel antagonists

Chronic stable angina pectoris (CSAP) resulting from coronary artery disease (CAD) is common in elderly patients, and significantly reduces their quality of life. Myocardial revascularisation procedures in this age group entail significant risks, largely related to comorbidities rather than advanced age itself. Coronary artery anatomy is more likely to be technically unsuitable for revascularisation and angina more resistant to drug treatment. Therefore, elderly patients often take combinations of antianginal drugs. Calcium channel antagonists (CCAs) are effective antianginal drugs first introduced for clinical use in the late 1970's. They reduce myocardial ischaemia by both causing vasodilatation of coronary resistance vessels and reducing cardiac workload (negative inotropic effect). However, adverse effects related to abrupt arterial vasodilatation limited the tolerability of these short acting 'first generation' drugs (nifedipine, verapamil and diltiazem). Furthermore, short acting nifedipine may occasionally increase both the frequency of angina pectoris and mortality in patients with CAD. Since then, long acting formulations of first generation agents and new chemical entities (second and third generation drugs) have been developed. These are well tolerated and effective at attenuating both myocardial ischaemia and the frequency and severity of angina pectoris in most patients with stable CAD. Current guidelines on the drug treatment of CSAP propose that beta-adrenoceptor antagonists (beta-blockers) should be used as first line medication primarily for their prognostic benefits, and that CCAs need only be introduced if beta-blockers are not tolerated, contraindicated or ineffective. Despite this, there is a wealth of evidence from clinical trials that demonstrate equal antianginal efficacy for CCAs and beta-blockers. The presence of chronic heart failure and prior myocardial infarction are clear indications for the use of beta-blockers in preference to CCAs for the treatment of CSAP. However, in patients with both CSAP and hypertension, second and third generation CCAs may offer prognostic benefits of similar magnitude to those provided by beta-blockers. Therefore, antianginal drug therapy must be tailored to the individual needs and comorbidities of each elderly patient.

Efficacy of Calcium Channel Blocker in the Secondary Prevention of Myocardial Infarction-Retrospective Analysis of the 10-Year Prognosis of Coronary Thrombolysis-Treated Patients-

BACKGROUND

Calcium channel blockers (CCBs) may have a positive influence on the long-term prognosis of Japanese patients with ischemic heart disease.

METHODS AND RESULTS

The effect of nifedipine-retard (NR) (n=202) compared with that of non-CCB treatment (n=92) on the secondary prevention of myocardial infarction (MI) was retrospectively investigated in patients who had survived acute MI between 1987 and 1996. The primary endpoint was the occurrence of cardiac death or non-fatal MI. The median follow-up was 6.3+/-2.4 years. The incidence of cardiac events was 8.9% in the NR group and 14.1% in the non-CCBs group (p=0.14, odds ratio (OR): 0.584, 95% confidence interval (CI): 0.286-1,193). However, subanalysis revealed that NR significantly reduced the incidence of cardiac events in patients aged less than 55 years (4.2 vs 18.2%, p=0.016, OR: 0.180, 95%CI: 0.045-0.721) and those who did not smoke (8.6 vs 16.4%, p=0.048, OR: 0.462, 95%CI: 0.203-0.999).

CONCLUSION

Although this was a retrospective analysis, it showed that NR did not cause an increase in the incidence of cardiac events in post-MI patients; it even prevented cardiac events, especially in those who were less than 55 years of age and in non-smokers, suggesting the potential usefulness of CCBs in the secondary prevention of MI in Japan.

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.

Current treatment of patients with hypertension: therapeutic implications of INSIGHT

When planning treatment for patients with hypertension, current guidelines emphasise the importance of risk stratification, based on blood pressure, the presence of end-organ damage and other cardiovascular risk factors. Because the beneficial effect of antihypertensive therapy seems to be linked to the degree of blood pressure reduction, guidelines recommend reducing blood pressure below 140/90mm Hg, with a lower target in patients who are young or who have diabetes mellitus (with or without nephropathy) or non-diabetic nephropathy. Blood pressure reduction can be achieved with several classes of drugs, including diuretics, beta-blockers, ACE inhibitors, angiotensin II antagonists and calcium channel antagonists. Calcium channel antagonists have been shown to reduce the risk of stroke and major cardiovascular events. However, it is still controversial whether different treatment regimens based on different drug classes can offer advantages beyond similar degrees of blood pressure control in preventing cardiovascular morbidity and mortality. The International Nifedipine GITS Study: Intervention as a Goal in Hypertension Treatment (INSIGHT) was a controlled clinical trial aimed at comparing the efficacy of a long-acting calcium channel antagonist, nifedipine gastrointestinal-transport-system (GITS), versus co-amilozide, a combination of the diuretics hydrochlorothiazide (HCTZ) and amiloride, on morbidity and mortality in high-risk hypertensive patients. Nifedipine GITS and HCTZ/amiloride were equally effective at reducing blood pressure and the risk of primary outcomes (a composite of death from any cardiovascular or cerebrovascular cause, non-fatal stroke, myocardial infarction and heart failure). Results from other studies indicate that there may be greater benefits for stroke and smaller benefits for coronary artery disease with calcium channel antagonist-based regimens than with diuretic or beta-blocker-based regimens. However, there is at present insufficient evidence to recommend a specific drug choice based on patient risk profile. Thus, the choice of antihypertensive drug(s) should be according to efficacy and tolerability. In addition to the reductions in cardiovascular risk, two substudies of INSIGHT showed that nifedipine GITS was able to prevent the progression of intima media thickness in the common carotid artery and slow the progression of coronary calcification. The clinical significance of this effect in the prevention of cardiovascular events still remains to be established.

The Differences Between ACE Inhibitor-Treated and Calcium Channel Blocker-Treated Hypertensive Patients

Large-scale outcome trials have demonstrated that blood pressure reduction with angiotensin-converting enzyme (ACE) inhibitors or calcium channel blockers (CCBs) is associated with reduced cardiovascular complications in hypertension. Comparative trials against conventional drugs and between ACE inhibitors and CCBs have failed to reveal conclusive differences in cause-specific outcomes. Studies in high-risk patients suggest that ACE inhibitors are superior to CCBs and other drugs in protection against cardiovascular events and renal disease. Very long-term prospectively collected observational data from the Glasgow Blood Pressure Clinic and the UK General Practice Research Database strongly support an advantage of ACE inhibitors over CCBs for cardiovascular morbidity and mortality. Considering all the available information, it can be concluded that the use of CCBs in the routine therapy of hypertension cannot be recommended while wider use of ACE inhibitors, along with low-dose diuretics and beta blockers, appears justified.

Long term effects of nisoldipine on the progression of coronary atherosclerosis and the occurrence of clinical events: the NICOLE study

BACKGROUND

Earlier angiographic studies have suggested that calcium antagonists may prevent the formation of new coronary lesions and the progression of minimal lesions. Conversely, a meta-analysis suggested that these drugs may increase cardiovascular mortality and morbidity in patients with coronary heart disease.

OBJECTIVE

To investigate whether nisoldipine retards the progression of coronary atherosclerosis or reduces the occurrence of clinical events.

DESIGN AND SETTING

The NICOLE study (NIsoldipine in COronary artery disease in LEuven) is a single centre, randomised, double blind, placebo controlled trial with coronary angiography at baseline, six months, and three years of follow up.

PATIENTS

826 patients who had undergone successful coronary angioplasty were randomised to nisoldipine 40 mg once daily or placebo. The intention to treat and per protocol population consisted of 819 and 578 patients, respectively.

RESULTS

In the per protocol population, 625 of the nisoldipine treated and 655 of the placebo treated patients (NS) showed angiographic progression in at least one coronary arterial segment, defined as an increase in diameter stenosis of > or = 13%. The average minimum luminal diameter of the non-dilated lesions decreased by 0.163 mm and 0.167 mm in the nisoldipine and placebo groups, respectively (NS). The respective numbers of new lesions detected were 7 and 13 (NS). In the intention to treat population, the rates of death, stroke, and acute myocardial infarction were similar in both treatment groups. However, nisoldipine use was associated with fewer revascularisation procedures and thus the percentage of patients with any clinical event was lower (44.6% v 52.6%, p = 0.02).

CONCLUSIONS

Nisoldipine has no demonstrable effect on the angiographic progression of coronary atherosclerosis or the risk of major cardiovascular events but its use is associated with fewer revascularisation procedures.

Differential effects of amlodipine and atorvastatin treatment and their combination on atherosclerosis in ApoE*3-Leiden transgenic mice

This study was designed to investigate the potential antiatherosclerotic effects of the calcium antagonist amlodipine as compared with the HMG-CoA reductase inhibitor atorvastatin and the combination of both in ApoE*3-Leiden transgenic mice. Four groups of 15 ApoE*3-Leiden mice were put on a high-cholesterol diet. One group received 0.002% (wt/wt) amlodipine in the diet, which had no effect on plasma cholesterol levels. Another group received 0.01% (wt/wt) atorvastatin, resulting in a decrease of plasma cholesterol by 50% by a reduction in very low density lipoprotein production. The combination group received both amlodipine and atorvastatin. After 28 weeks, atherosclerosis in the aortic root was quantified. Treatment with amlodipine had no significant effect on atherosclerotic lesion area, whereas atorvastatin markedly reduced atherosclerosis by 77% compared with the control group. Atorvastatin also reduced inflammation markers. The combination of amlodipine and atorvastatin tended to reduce lesion area by 61% compared with the atorvastatin-only group; however, this effect did not reach statistical significance. Amlodipine treatment significantly reduced calcification in the lesions, whereas atorvastatin alone had no effect. The combination of amlodipine and atorvastatin resulted in a near absence of calcium deposits in the lesions. This study demonstrates that amlodipine treatment alone does not significantly reduce atherosclerotic lesion development. Atorvastatin was shown to have strong antiatherosclerotic effects, and cotreatment with amlodipine may potentiate the antiatherosclerotic effect of atorvastatin.