Prevention of coronary heart disease with pravastatin in men with hypercholesterolemia. West of Scotland Coronary Prevention Study Group

Changing paradigms in thrombolysis in acute myocardial infarction

Acute myocardial infarction occurs when a ruptured coronary artery plaque causes sudden thrombotic occlusion of a coronary artery and cessation of coronary artery blood flow. This paper reviews the underlying coronary pathology in progressive coronary atherosclerosis, mechanisms of plaque rupture and arterial occlusion and the time relationship between coronary occlusion and myocardial necrosis. Reperfusion can be achieved by chemical thrombolysis with different thrombolytic agents. Early lysis is achieved best by prehospital administration, a transtelephonic monitor, a mobile intensive care unit, active general practitioner treatment or by warning the emergency room of impending arrival of a patient. Thrombolytic therapy may be unsuccessful and not achieve Grade III TIMI flow in less than 4 h (or even 2 h) due to inadequate or intermittent perfusion or reocclusion. Adjuvant therapy includes aspirin and platelet receptor antagonists. Bleeding is a constant danger. Direct percutaneous transluminal coronary angioplasty (PTCA) may be as effective or better than chemical thrombolysis. Reperfusion protects the myocardium and salvages viable tissue. It also improves mechanical remodelling of the ventricle. Long-term follow-up has shown that quantum leaps of fresh coronary occlusion causes step-wise progression in patient disability and that further early, prompt reperfusion can salvage myocardium and prevent this inexorable progress of the disease.

The clinical therapeutic implications of the Scandinavian Simvastatin Survival Study

This analysis of the Scandinavian Simvastatin Survival Study (4S) describes how the design, implementation, and results answer most questions or concerns of practicing physicians regarding practicality and advantages of blood cholesterol-lowering drug intervention in patients who already have coronary artery disease. The results demonstrated that a drug with the safety and efficacy profile of simvastatin, utilized as it would be in a physician's office, can improve mortality and morbidity in patients with existing coronary disease without important side effects, and reduce hospitalizations for patients with coronary heart disease.

A rational approach to treating hypercholesterolaemia in children. Weighing the risks and benefits

Because atherosclerosis is a continuous process throughout life, expert panels have suggested guidelines to reduce the risk of cardiovascular disease, starting from childhood. The guidelines focus on population-based measures and on treating hypercholesterolaemia in individual children. Low-fat diets in children have been widely debated. There is little evidence that growth is stunted or that nutritional deficiencies arise if the energy that is lost by limiting fat intake is substituted with other nutrients. Dietary fibre, plant sterols and fish oils have been used to modify lipid levels in children; however, the efficacy of these dietary adjuncts is limited. Bile acid-binding resins are the only approved drugs to lower cholesterol levels in children and appear to be well tolerated. However, compliance with resins is low because of unpalatability, so low dosages are preferred and vitamin supplementation is prudent. Data on HMG CoA reductase inhibitors and fibrates are insufficient to recommend these drugs at present. Drug treatment should be restricted to children who are at exceptionally high risk of disease, usually those with genetic dyslipidaemias.

Effect of simvastatin therapy on cell membrane cholesterol content and membrane function as assessed by polymorphonuclear cell NADPH oxidase activity

Cell membrane cholesterol is an important determinant of membrane fluidity. Changes in fluidity have important consequences for membrane function. Treatment of hypercholesterolaemia could therefore affect membrane function by reducing cell membrane cholesterol levels. The aim of this study was to determine whether treatment with simvastatin affects membrane cholesterol and the activity of the polymorphonuclear cell membrane enzyme NADPH oxidase. Blood was obtained from 12 hypercholesterolaemic patients before, and 6 weeks after, treatment with simvastatin, and from 20 normolipidaemic subjects. Cell cholesterol was in the unesterified from indicating that it was membrane-associated. Pre-treatment mean cell cholesterol concentration in the hyperlipidaemics was higher (P < 0.05) than in the normolipidaemics [4.19 fmol/cell, 95% confidence interval (CI) 3.38-5.05 versus 3.10 fmol/cell, 95% CI 2.58-3.61]. There was a strong correlation between cell cholesterol content and NADPH oxidase lag phase (R(s) = 0.76, P < 0.01). Cell cholesterol fell to 3.52 fmol/cell (95% CI 2.77-4.28, P < 0.05) following treatment and there was a correlation (R(s) = 0.61, P < 0.05) between the reductions in cell cholesterol and lag phase.

Stroke, statins, and cholesterol. A meta-analysis of randomized, placebo-controlled, double-blind trials with HMG-CoA reductase inhibitors

BACKGROUND AND PURPOSE

To estimate the effect of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors ("statins") on stroke ris, we combined the data of the randomized, placebo-controlled, double-blind trials with HMG-CoA reductase inhibitors published so far.

METHODS

The studies were identified using the Medline CD+ and Current Contents databases from January 1980 through May 1996, inclusive. All studies were evaluated on the use of a placebo control, monotherapy, and double blindness. When the type of stroke or the occurrence of clinical events or adverse effects were incompletely or not reported, the investigators were contacted personally. For each trial, the number of strokes in the treatment arm was compared with the number of strokes expected on all observations under the assumption that drug treatment had no effect.

RESULTS

A total of 462 strokes among 20438 participants in 13 trials could be analyzed. A total of 181 strokes were observed in patients randomized to treatment with an HMG-CoA reductase inhibitor and 261 strokes in patients randomized to placebo. A lower than expected number of strokes was observed in the treatment groups of all but one trial (P = .001). Treatment with an HMG-CoA reductase inhibitor led to an overall risk reduction of 31% (odds ratio, 0.69; 95% confidence interval, 0.57 to 0.83).

CONCLUSIONS

The combined data suggest that treatment with HMG-CoA reductase inhibitors prevents stroke in middle-aged persons. Because stroke is especially common in older age, these data reinforce the need for clinical trials to evaluate the effect of HMG-CoA reductase inhibitors in preventing stroke in the elderly.

Comparison of pravastatin with crystalline nicotinic acid monotherapy in treatment of combined hyperlipidemia

Pravastatin treatment of combined hyperlipidemia lowers low-density lipoprotein effectively; nicotinic acid lowers remnant cholesterol and raises high-density lipoprotein. A combination of these 2 drugs may be indicated for optimal treatment of lipoprotein abnormalities in combined hyperlipidemia.

Effects of low-dose simvastatin therapy on serum lipid levels in patients with moderate hypercholesterolemia: a 12-month study. The Simvastatin Study Group

The aim of this study was to investigate the safety and long-term effects on serum lipid levels of low-dose simvastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, in Japanese patients with moderate primary hypercholesterolemia. We assigned 201 patients (68 men and 133 women; mean +/- SD age, 61.3 +/- 10.2 years) with serum total cholesterol levels > or = 220 mg/dL to receive simvastatin 5 mg each evening; the treatment period was 1 year. Serum total cholesterol, triglycerides, and low-density lipoprotein (LDL) cholesterol levels decreased significantly in response to simvastatin therapy, and the changes were maintained throughout the treatment period. Mean total cholesterol decreased from 269.9 +/- 35.4 mg/dL to 215.2 +/- 34.5 mg/dL (20.3%), triglycerides decreased from 183.0 +/- 110.2 mg/dL to 155.5 +/- 88.5 mg/dL (15.0%), and LDL cholesterol decreased from 180.0 +/- 33.1 mg/dL to 130.1 +/- 35.1 mg/dL (27.7%). Total cholesterol, triglycerides, and LDL cholesterol tended to decline when the pretreatment values were higher; the critical values and the bidirectional changes of the serum lipid levels were 188.1, 109.5, and 91.6 mg/dL, respectively. Although the serum level of high-density lipoprotein cholesterol did not change significantly, it tended to increase more when the pretreatment values were lower; the "critical value" was 70 mg/dL. Nine patients experienced mild adverse events, but none discontinued simvastatin during the 12-month treatment period. We found that low-dose simvastatin therapy is effective in achieving long-term decreases in serum lipid levels and is well tolerated by patients with moderate hypercholesterolemia. Simvastatin therapy may result in normalization of serum lipid levels.

Lipid modifying agents: mechanisms of action and reduction of cardiovascular disease

1. Recent studies (4S, CARE, WOSCOPS) with the HMG CoA reductase inhibitors have shown that reductions of total cholesterol and LDL cholesterol reduce the risk for a new fatal or non-fatal cardiac event by approximately 30-35%, providing LDL is decreased by 25-35%. 2. Preliminary data also suggest that achieved LDL levels around 3.2 mmol/L results in no greater reduction in new events than when LDL is lowered even further. 3. There is considerable debate, nonetheless, as to whether these reduction in cardiovascular events are entirely a consequence of LDL reduction or whether the lipid-modifying agents have effects on lipoprotein structure, endothelial cell function, clotting and haemorrheological pathways. 4. The study results achieved with statins have obscured the role of fibrates as useful agents for reducing cardiovascular disease. Fibrates have a different mode of action to stains by reducing triglyceride-rich lipoprotein precursors and favourably altering LDL and HDL composition. 5. The practising clinician needs to consider the lipoprotein phenotype and to choose whether the ideal treatment is stain alone, fibrate alone or perhaps a combination.

Atorvastatin. A review of its pharmacology and therapeutic potential in the management of hyperlipidaemias

Atorvastatin is a synthetic HMG-CoA reductase inhibitor which lowers plasma cholesterol levels by inhibiting endogenous cholesterol synthesis. It also reduces triglyceride levels through an as yet unproven mechanism. Dose-dependent reductions in total cholesterol, low density lipoprotein (LDL)-cholesterol and triglyceride levels have been observed with atorvastatin in patients with hypercholesterolaemia and in patients with hypertriglyceridaemia. In large trials involving patients with hypercholesterolaemia, atorvastatin produced greater reductions in total cholesterol, LDL-cholesterol, apolipoprotein B and triglyceride levels than lovastatin, pravastatin and simvastatin. In patients with primary hypercholesterolaemia, the combination of atorvastatin and colestipol tended to produce larger reductions in LDL-cholesterol levels and smaller reductions in triglyceride levels than atorvastatin monotherapy. Although atorvastatin induced smaller reductions in triglyceride levels and more modest increases in high density lipoprotein (HDL)-cholesterol levels than either fenofibrate or nicotinic acid in patients with combined hyperlipidaemia, it produced larger reductions in total cholesterol and LDL-cholesterol. As with other HMG-CoA reductase inhibitors, the most frequently reported adverse events associated with atorvastatin are gastrointestinal effects. In comparative trials, atorvastatin had a similar adverse event profile to that of other HMG-CoA reductase inhibitors. Clinical data with atorvastatin are limited at present. However, with its ability to markedly reduce LDL-cholesterol levels, atorvastatin is likely to join other members of its class as a first-line agent for the treatment of patients with hypercholesterolaemia, if changes in lipid levels with atorvastatin convert to reductions in CHD mortality and morbidity. Atorvastatin may be particularly suitable for patients with heterozygous or homozygous familial hypercholesterolaemia because of the marked reductions in LDL-cholesterol experienced with the drug. Additionally, because of its triglyceride-lowering properties, atorvastatin appears to have the potential to become an appropriate treatment for patients with combined hyperlipidaemia or hypertriglyceridaemia.

Pharmacodynamics and pharmacokinetics of the HMG-CoA reductase inhibitors. Similarities and differences

Hypercholesterolaemia plays a crucial role in the development of atherosclerotic diseases in general and coronary heart disease in particular. The risk of progression of the atherosclerotic process to coronary heart disease increases progressively with increasing levels of total serum cholesterol or low density lipoprotein (LDL) cholesterol at both the individual and the population level. The statins are reversible inhibitors of the microsomal enzyme HMG-CoA reductase, which converts HMG-CoA to mevalonate. This is an early rate-limiting step in cholesterol biosynthesis. Inhibition of HMG-CoA reductase by statins decreases intracellular cholesterol biosynthesis, which then leads to transcriptionally upregulated production of microsomal HMG-CoA reductase and cell surface LDL receptors. Subsequently, additional cholesterol is provided to the cell by de novo synthesis and by receptor-mediated uptake of LDL-cholesterol from the blood. This resets intracellular cholesterol homeostasis in extrahepatic tissues, but has little effect on the overall cholesterol balance. There are no simple methods to investigate the concentration-dependent inhibition of HMG-CoA reductase in human pharmacodynamic studies. The main clinical variable is plasma LDL-cholesterol, which takes 4 to 6 weeks to show a reduction after the start of statin treatment. Consequently, a dose-effect rather than a concentration-effect relationship is more appropriate to use in describing the pharmacodynamics. Fluvastatin, lovastatin, pravastatin and simvastatin have similar pharmacodynamic properties; all can reduce LDL-cholesterol by 20 to 35%, a reduction which has been shown to achieve decreases of 30 to 35% in major cardiovascular outcomes. Simvastatin has this effect at doses of about half those of the other 3 statins. The liver is the target organ for the statins, since it is the major site of cholesterol biosynthesis, lipoprotein production and LDL catabolism. However, cholesterol biosynthesis in extrahepatic tissues is necessary for normal cell function. The adverse effects of HMG-reductase inhibitors during long term treatment may depend in part upon the degree to which they act in extrahepatic tissues. Therefore, pharmacokinetic factors such as hepatic extraction and systemic exposure to active compound(s) may be clinically important when comparing the statins. Different degrees of liver selectivity have been claimed for the HMG-CoA reductase inhibitors. However, the literature contains confusing data concerning the degree of liver versus tissue selectivity. Human pharmacokinetic data are poor and incomplete, especially for lovastatin and simvastatin, and it is clear that any conclusion on tissue selectivity is dependent upon the choice of experimental model. However, the drugs do differ in some important aspects concerning the degree of metabolism and the number of active and inactive metabolites. The rather extensive metabolism by different cytochrome P450 isoforms also makes it difficult to characterise these drugs regarding tissue selectivity unless all metabolites are well characterised. The effective elimination half-lives of the hydroxy acid forms of the 4 statins are 0.7 to 3.0 hours. Protein binding is similar (> 90%) for fluvastatin, lovastatin and simvastatin, but it is only 50% for pravastatin. The best characterised statins from a clinical pharmacokinetic standpoint are fluvastatin and pravastatin. The major difference between these 2 compounds is the higher liver extraction of fluvastatin during the absorption phase compared with pravastatin (67 versus 45%, respectively, in the same dose range). Estimates of liver extraction in humans for lovastatin and simvastatin are poorly reported, which makes a direct comparison difficult.

A brief review paper of the efficacy and safety of atorvastatin in early clinical trials

Preclinical and clinical data on atorvastatin, a new 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, indicate that it has superior activity in treating a variety of dyslipidemic disorders characterized by elevations in low-density lipoprotein cholesterol (LDL-C) and/or triglycerides. Results for patients randomized in early efficacy and safety studies were combined in one database and analyzed. This analysis included a total of 231 atorvastatin-treated patients (131 with hypercholesterolemia (HC), 63 with combined hyperlipidemia (CH), 36 with hypertriglyceridemia (HTG), and 1 with hyperchylomicronemia (Fredrickson Type V)). Patients were treated with a cholesterol-lowering diet (National Institutes of Health National Cholesterol Education Program Step 1 diet or a more rigorous diet) and either 2.5, 5, 10, 20, 40, or 80 mg/day of atorvastatin or placebo. Efficacy was based on percent change from baseline in total cholesterol, total triglycerides, LDL-C, very low-density lipoprotein cholesterol (VLDL-C), high-density lipoprotein cholesterol (HDL-C), apolipoprotein B (apo B), and non-HDL-C/HDL-C. Safety was assessed in all randomized patients. Atorvastatin seemed to preferentially lower those lipid and lipoprotein component(s) most elevated within each dyslipidemic state: LDL-C in patients with HC, triglycerides and VLDL-C in patients with HTG, or all 3 in patients with CH. Atorvastatin was well-tolerated with a safety profile similar to other drugs in its class.

Inhibition of proliferation of human smooth muscle cells by various HMG-CoA reductase inhibitors; comparison with other human cell types

The effects of 6 HMG-CoA reductase inhibitors: pravastatin, lovastatin, simvastatin, atorvastatin, fluvastatin and cerivastatin were analyzed in cultured human smooth muscle cells, fibroblasts, endothelial cells and myoblasts. In vascular smooth muscle cells, pravastatin was a much weaker inhibitor of cholesterol synthesis than the 5 other drugs which displayed equally strong inhibitory potency. The anti-proliferative effects of these 6 drugs were analyzed by measuring cell number and mitochondrial dehydrogenase activity (MTT assay) after 3 days of incubation. IC25 values for inhibition of proliferation were very similar among the 4 cell types and were in the following order of magnitude: pravastatin << lovastatin = simvastatin = atorvastatin = fluvastatin << cerivastatin. Only in the case of pravastatin was proliferation inhibited at lower concentration in smooth muscle cells than in the other cell types. Proliferation was also assessed by measuring DNA synthesis in these cells. A 3 day-incubation with 1 microM of pravastatin had no effect on this parameter in all 4 cell types. However, 1 microM of simvastatin or lovastatin caused either an inhibition (in smooth muscle cells and endothelial cells) or stimulation (in fibroblasts) of this process. The effects of simvastatin on cell number, mitochondrial dehydrogenase activity and DNA synthesis were counteracted by simultaneous mevalonate addition. Simvastatin treatment was also associated with a change in the post-translational modification of the ras protein in smooth muscle cells, probably by inhibition of its farnesylation. Moreover, simvastatin treatment blocked the PDGF and bFGF-induced DNA synthesis in synchronized smooth muscle cells, whereas it does not affect the fetal calf serum-induced DNA synthesis in synchronized fibroblasts, suggesting that simvastatin blocks various steps of the cell cycle and that this effect depends on the cell type and the growth signalling pathway activated.

Human lesion studies

We describe recent information on the atherothrombotic processes leading to the acute coronary syndromes (ACS) in humans. Then, we outline the mechanism of action and impact of lipid-lowering therapy in stabilization and secondary prevention of such processes. We start with (1) definitions of atherosclerotic lesions. In the progression of coronary atherosclerosis, eight morphologically different lesions are defined (Type I to VI) in various phases of disease. (2) Then we discuss vulnerable lipid-rich plaques and ACS. The type IV and Va lesions tend to be relatively small in size, but soft or vulnerable to disruption (with subsequent thrombosis) because of high lipid content (cholesterol esters rather than free cholesterol monohydrate crystals). The above process represents a "passive" phenomenon of plaque disruption. In addition to this "passive" phenomenon, an "active," macrophage-dependent, phenomenon of plaque disruption is evolving. (3) We then show the role of thrombosis in ACS. Monocytes/macrophages in lipid-rich plaques may play a detrimental role after plaque disruption, promoting thrombin generation and thrombosis through the tissue factor pathway, which can be prevented by tissue factor pathway inhibitor. Such thrombotic phenomena are critical in the development of ACS. (4) Finally, we discuss the effect of lipid-modifying strategies on the vulnerable lipid-rich plaques. When high LDL-cholesterol is reduced therapeutically, efflux from the plaques of the liquid or sterified cholesterol, and also its hydrolysis into cholesterol crystals depositing in the vessel wall, predominate over the influx of LDL-cholesterol. Consequently, there is a decrease in the softness of the plaque and so, presumably in the "passive" phenomenon of plaque disruption. When low HDL-cholesterol is increased experimentally, there is a partial decrease in the number and activity of the macrophages and so, presumably in the "active" phenomenon of plaque disruption.

The efficacy of lovastatin in lowering cholesterol in African Americans with primary hypercholesterolemia

PURPOSE

To evaluate the efficacy of lovastatin in African Americans (AA) diagnosed with primary hypercholesterolemia.

PATIENTS AND METHODS

Forty-seven AA patients from the King/Drew Medical Center in Los Angeles were recruited from the Hypertension, Family Practice, and General Medicine Clinics for a double-blinded, placebo-controlled trial. Forty-one patients completed the 10 week study. Eligibility for entrance into the study was determined by patient lipid profiles meeting the criteria for pharmacological intervention outlined by the National Cholesterol Education Program II guidelines. Patients were randomized into 2 groups: lovastatin 20 mg per day, or placebo. A registered dietitian counseled both groups on two visits during the study to ensure compliance with a low fat, low cholesterol diet. Lipid levels were compared at the first and last visit of the study.

RESULTS

The lovastatin-treated group demonstrated significant reductions in mean total cholesterol (TC) (14.7%, 95% confidence interval [CI]-6.6 to -22.8, P < 0.01) and low-density lipoprotein (LDL) cholesterol (20.0%, 95% CI-7.9 to -32.1, P < 0.01) from baseline. Plasma triglyceride (TG) levels decreased by 10.5% (95% CI-2.4 to -18.6) and total cholesterol/high density lipoprotein (HDL) ratio fell below five in the lovastatin group, but neither reduction reached statistical significance. Placebo administration was not associated with any significant changes in TC, LDL, or TG. There were no significant differences between baseline and post-treatment hepatic transaminase levels in either group.

CONCLUSIONS

The HMG-CoA (3-hydroxyl-3 methylglutary coenzyme A) reductase inhibitor lovastatin in a dose of 20 mg per day was effective in decreasing TC, LDL, and TG levels in an AA population. Considering that the AA population is at substantially increased risk for hypertension and cardiovascular morbidity, more aggressive and wider use of HMG-CoA reductase inhibitors should be employed in reducing elevated plasma cholesterol levels.

Hemodynamic changes associated with reduction in total cholesterol by treatment with the HMG-CoA reductase inhibitor pravastatin

Hemodynamic changes associated with the lowering of total cholesterol (TC) by the water-soluble HMG-COA reductase inhibitor pravastatin were investigated in 59 patients with hypercholesterolemia (TC level at least 220 mg/dl) who received pravastatin therapy for 6 months. The patients were divided into two groups according to the reduction in TC: a > or = 15% reduction group and a < 15% reduction group. The changes in hemodynamics were compared before and after pravastatin treatment. No changes in blood pressure, heart rate or aortic damping factor were found in either group. However, significant decreases in pulse wave velocity and total peripheral resistance, and increase in cardiac output were seen in the > or = 15% reduction group. All these hemodynamic parameters remained unchanged in the < 15% reduction group. The 12 patients with a clear pravastatin-induced reduction in TC maintained over a 5-year period showed no changes in blood pressure, heart rate or aortic damping factor, but the reductions in pulse wave velocity and total peripheral resistance, and increase in cardiac output were maintained. These changes in hemodynamics were not dependent on aortic elasticity, and appeared to result from improved peripheral hemodynamics. Lowering of TC levels by pravastatin results in improvement in the peripheral endothelium-dependent vasodilation disorder associated with hypercholesterolemia.

Aspirin protects low density lipoprotein from oxidative modification

OBJECTIVE

To examine the effects of aspirin on the potential for oxidative modification of low density lipoprotein (LDL).

DESIGN

Before and after trial.

SETTING

University department of medicine within a district general hospital campus.

PATIENTS

Ten healthy normolipidaemic volunteers drawn from laboratory and medical staff.

INTERVENTIONS

Aspirin (enteric coated) 300 mg daily for two weeks.

MAIN OUTCOME MEASURES

In vitro oxidation of LDL following ultraviolet C (UVC) irradiation with measurements made of malondialdehyde, conjugated dienes, and electrophoretic mobility.

RESULTS

There was a significant decrease in malondialdehyde production from LDL modified by aspirin in vivo following exposure to UVC irradiation for 90 minutes, culminating in a 30% decrease by 240 minutes (mean (SD) 64.2 (9.12) v 89.6 (11.6) nmol/mg LDL protein, P = 0.029). These observations were borne out using LDL modified by aspirin in vitro. The UVC induced increase in relative electrophoretic mobility of LDL was also significantly reduced following aspirin treatment (mean (SD) 2.17 (0.16) v 2.66 (0.24), P = 0.012).

CONCLUSIONS

Aspirin, both in vivo and in vitro, protects LDL against subsequent oxidative modification, providing an additional mechanism whereby aspirin may protect against atherosclerosis.

Efficacy and safety of atorvastatin compared to pravastatin in patients with hypercholesterolemia

Plasma cholesterol and other lipoproteins play a significant role in the development of atherosclerosis and subsequent coronary heart disease (CHD). This 1 year study was designed to confirm the efficacy and safety of atorvastatin (Lipitor) compared to pravastatin, a marketed agent for low density lipoprotein cholesterol (LDL-C) reduction in hypercholesterolemic patients. Patients were recruited at 26 centers in six European countries. After a 6 week placebo baseline phase, patients were randomized to receive atorvastatin 10 mg or pravastatin 20 mg daily. The dose could be doubled at week 16, if LDL-C levels remained > or = 3.4 mmol/l (135 mg/dl). Atorvastatin significantly lowered LDL-C from baseline by 35% compared with 23% for pravastatin (P < 0.05). A total of 72% of atorvastatin patients attained the LDL-C target level of < 3.4 mmol/l, compared to 26% of pravastatin patients. Atorvastatin also significantly reduced TC, TG and apo B (P < 0.05). Safety was assessed by recording adverse events and measuring clinical laboratory parameters. The adverse event profile was similar for both treatment groups and neither treatment caused clinically relevant laboratory abnormalities. Atorvastatin 10 and 20 mg once daily is superior to pravastatin 20 and 40 mg once daily in treating patients with hypercholesterolemia.

Do codeine and caffeine enhance the analgesic effect of aspirin?--A systematic overview

OBJECTIVE

To assess whether codeine and caffeine enhance the analgesic effect of aspirin in post-operative pain.

METHOD

Systematic overview of the literature and meta-analysis of published randomized controlled trials (RCTs).

RESULTS

Codeine 60 mg leads to a small increase in the analgesic effect of 650 mg of aspirin when total pain relief score (TOTPAR%) is used as a efficacy end-point. This increased effect was not seen when sum of pain intensity (SPID%) and proportions of patients responding with moderate to excellent pain relief were used as outcome measures. Caffeine did not enhance the analgesic effect of aspirin.

CONCLUSION

Codeine 60 mg may produce a small increase in the analgesic effect of aspirin 650 mg. However, this effect is not clinically meaningful. Caffeine has no adjuvant analgesic effect. At over-the-counter (OTC) doses, caffeine and codeine are not useful in aspirin formulations.

Non-pharmacological modification of cardiac risk factors: Part 2. The role of diet

A high intake of saturated fats and cholesterol is associated with an increased risk of developing and dying from coronary artery disease (CHD), particularly if other risk factors are present. However, although a reduction in the consumption of the amounts of saturated fat and cholesterol may reduce the incidence of primary and secondary CHD in susceptible individuals, other dietary measures may also be important. These include an increased consumption of poly- and monounsaturated fatty acids, fresh fruit, fish and fibre.

Tamoxifen decreases cholesterol sevenfold and abolishes lipid lesion development in apolipoprotein E knockout mice

BACKGROUND

Apolipoprotein E (apo E) knockout mice develop severe vascular lipid lesions resembling human atherosclerotic plaques, irrespective of the fat content of their diet.

METHODS AND RESULTS

Oral tamoxifen (TMX) at a dose of 1.9 mg.kg body wt-1.d-1 abolished lipid lesion development, assayed by oil red O staining, whether the mice were fed a normal diet or a diet with high fat content. The TMX-treated mice showed a sevenfold decrease in total cholesterol. However, the proportion of plasma cholesterol present in VLDL remained unchanged, whereas the proportion in LDL decreased by 37%, and that in HDL increased by 64%. Consistent with the shift from LDL to HDL cholesterol, there was a 62% decrease in total triglycerides. The concentrations of active and acid-activatable latent plus active TGF-beta in the aorta were substantially elevated by TMX (87% and 24% increase, respectively).

CONCLUSIONS

Although the mechanism of cardiovascular protection by TMX in apo E knockout mice is unknown, the inhibition of lipid lesion formation may be attributable to the changes in lipoprotein profile and the elevated levels of TGF-beta, both of which are thought to be protective against atherosclerosis in humans and animal models.

Baseline risk factors and their association with outcome in the West of Scotland Coronary Prevention Study. The West of Scotland Coronary Prevention Study Group

The West of Scotland Coronary Prevention Study recently demonstrated the benefits of pravastatin therapy in the prevention of coronary heart disease events in middle-aged hypercholesterolemic men without prior myocardial infarction. We present an analysis of the influence of baseline risk factors on coronary events and total mortality in the trial, and their interaction with therapy, using the Cox proportional hazards model. The multivariate predictors of fatal or nonfatal coronary events were treatment allocation (pravastatin or placebo), current smoking, diabetes mellitus, nitrate consumption, minor electrocardiographic abnormalities, angina pectoris, family history of premature coronary death, widowhood, blood pressure, and total cholesterol/high density lipoprotein cholesterol ratio. Independent of other risk factors, pravastatin reduced the risk of definite coronary heart disease death or nonfatal myocardial infarction by 32% (95% confidence interval 17 to 44, p = 0.0001), definite or suspected coronary heart disease death by 35% (3 to 56, p = 0.035), cardiovascular death by 33% (4 to 53, p = 0.027), coronary revascularization procedures by 38% (11 to 56, p = 0.009), and all-cause mortality by 24% (2 to 41, p = 0.037). The 5-year risk of fatal or nonfatal myocardial infarction, calculated using the predictors identified in the Cox analysis, ranged from <4.4% in the lowest quartile of risk to >9.6% in the highest quartile. The proportional benefit achieved by pravastatin was independent of other risk factors; hence, the absolute benefit of therapy was greatest in subjects with the highest baseline risk. Such subjects can be identified easily in the population and deserve high priority for treatment.

Cell dysfunction in atherosclerosis and the ischemic manifestations of coronary artery disease

Many of the cellular mechanisms and dysfunctions that underlie atherosclerotic plaque formation have been identified, including adverse interactions between atherogenic lipids and the arterial endothelium, loss of endothelium-dependent dilation, accumulation of inflammatory cells and mediators of inflammation in the intima of the arteries, and a decline in anticoagulant defenses. Several studies have shown that these mechanisms, which appear to be active throughout the pathogenesis and progression of atherosclerosis, are reversible within days, weeks, or months with effective lipid-lowering therapy. In addition, the findings of large-scale trials of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors suggest that the rapid improvement observed in trial participants is attributable to a reversal of endothelial and vascular wall dysfunctions rather than to a reduction in plaque size. The accumulated evidence indicates that improved endothelial function can benefit patients who have angina pectoris and/or are at risk for myocardial infarction. Current understanding of the cellular mechanisms of atherogenesis also suggests avenues of future research to refine treatment approaches and further improve outcomes for patients with coronary artery disease.

The potential use of angiotensin-converting enzyme inhibitors in patients with hyperlipidemia

New evidence suggests an interaction between hyperlipidemia, activation of the renin-angiotensin system, and atherosclerotic disease. In patients with atherosclerosis and hyperlipidemia, coronary endothelial dysfunction is usually diffuse and affects vasomotor tone, platelet activity, thrombosis, fibrinolysis, and regulation of inflammatory cells. Angiotensin II, an important oxidant, alters the binding of low-density-lipoprotein (LDL) cholesterol to its receptors and increases endothelial uptake of LDL. Endothelial dysfunction is worsened by the suppression of nitric oxide production and/or release via angiotensin II-associated degradation of bradykinin and oxygen free radical production, resulting in inadequate vasorelaxation. Therapy with angiotensin-converting enzyme (ACE) inhibitors appears to eliminate these untoward effects and may ameliorate the tendency for myocardial infarction associated with elevated plasma levels of angiotensin II. Although the role of ACE inhibitors in the prevention and/or treatment of coronary artery disease in patients without left ventricular dysfunction remains to be established, the capacity of ACE inhibition to correct endothelial dysfunction offers promise. The ability of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors to improve endothelial function, prevent the progression of coronary atherosclerosis, reduce the incidence of ischemic events, and improve survival is well known. Potentially, ACE inhibitors may have an additive or synergistic effect on the development of atherosclerosis and the clinical consequences of this disease when used in combination therapy with lipid-lowering strategies.

Simvastatin, an HMG-coenzyme A reductase inhibitor, improves endothelial function within 1 month

BACKGROUND

Cholesterol-lowering therapy can improve cardiovascular morbidity and mortality in patients with atherosclerosis. Although the mechanisms responsible are unclear, these benefits precede macroscopic changes in the vasculature. Emerging evidence that improvement in endothelial function may occur requires substantiation; in particular, it is unclear how early any such improvement would be detectable after initiation of therapy.

METHODS AND RESULTS

This randomized, double-blind, placebo-controlled crossover study evaluated the effect of simvastatin (20 mg daily for 4 weeks) on endothelium-dependent and endothelium-independent vasodilation and on the response to the inhibitor of nitric oxide synthesis, NG-monomethyl-L-arginine (L-NMMA), in the forearm vasculature of subjects with moderate elevation of total serum cholesterol (6.0 to 10.0 mmol/L) by use of strain-gauge plethysmography. Studies were repeated after 3 more months of open therapy. When the results are expressed as percentage changes in flow in the infused arm relative to the noninfused arm, the vasodilator response to acetylcholine was significantly increased after 4 weeks of treatment with simvastatin (P < .0005), and this improvement was further enhanced after 3 months (P < .005). Concurrently, simvastatin augmented the vasoconstrictor response to L-NMMA, an effect that was maintained at 3 months (P < .0005). The response to the endothelium-independent vasodilator sodium nitroprusside was unaltered.

CONCLUSIONS

These observations indicate that within 1 month of treatment with simvastatin, both the stimulated and basal nitric oxide dilator functions of the endothelium are augmented, and the benefits of this HMG-coenzyme A reductase inhibitor persist with continued therapy.

Cardiac complications in non-insulin-dependent diabetes mellitus

There is clear evidence of the negative influence of type I or II diabetes non-insulin-dependent diabetes mellitus (NIDDM) on the prevalence, severity, and prognosis of cardiovascular disease. Epidemiologic studies have confirmed the relationship between NIDDM and the occurrence of coronary artery disease (CAD) and cardiac heart failure (CHF). The clinical aspects of NIDDM cardiac complications include a high rate of silent events, which merit an improvement in their diagnosis and treatment. Besides pharmacological therapy, aggressive approaches including percutaneous transluminal coronary angioplasty (PTCA), and coronary surgery should be considered for the treatment of stable angina. IN some subgroups, the benefit of surgery has been proven. Available data indicate that diabetes (both type I and II) is a risk factor for an increase in morbidity and mortality following coronary bypass surgery. These data do not differentiate results between type I and type II diabetes. The indications for surgical revascularization are: three-vessel disease, left main artery stenosis, two-vessel disease including proximal left anterior descending artery stenosis, and two-vessel disease with left ventricular dysfunction. For PTCA, diabetes (type I more than type II) renders the technique more difficult and restenosis more frequent. From the results obtained in the general population and from a few specific studies, it is suspected that, in type II diabetes, PTCA and CABG are superior to conventional medical treatment. However, further specific studies on the beneficial effects of PTCA/CABG over optimal medical therapy are needed, at least in some angiographic conditions. Management of the diabetic patient with acute myocardial infarction is for the most part similar to the nondiabetic patient, with certain special considerations. Treatment includes thrombolytic therapy, invasive management, surgery, PTCA, beta blocker use, and aspirin use. Finally, diabetes mellitus is a cause of systolic and diastolic function, leading to clinical signs of CHF. Conventional medical therapy also applies to cardiac failure complicating diabetes. Medical therapy includes as the first line diuretics and angiotensin-converting enzyme inhibitors. We conclude that cardiac care can be improved in diabetic patients. For the time being, the first step is to improve the detection of coronary artery disease. As serious events are more likely to occur in the diabetic population, it would be easier (shorter studies and less patients) to demonstrate the benefit of a selected therapy. Further studies are therefore required. In the meantime, special efforts can be made: (1) prevent the development of coronary artery disease. Preventive measures aimed at the control of risk factors at the individual level must be optimal. What should be promoted is a more global approach to the patient, taking into account all parts of the risk factor profile, in order to amplify the reduction in risk and in cardiovascular morbidity and mortality. (2) When CAD is confirmed: the goal is to prevent all major cardiac events: unstable angina, myocardial infarction, sudden death, and CHF secondary to silent ischemic events. This can be achieved through the improvement of the accuracy of noninvasive diagnostic procedures, taking into account the cost of these procedures and the absence of pain perception in diabetic patients.

Improvement of erythrocyte deformability by cholesterol-lowering therapy with pravastatin in hypercholesterolemic patients

Erythrocyte deformation is an important regulatory factor of the microcirculation. The present study was designed to examine whether erythrocyte deformability is altered in hypercholesterolemic patients and, if so, whether cholesterol-lowering therapy affects this parameter in these patients. The erythrocyte deformability of 37 hypercholesterolemic patients was evaluated before and after 1 year of therapy with pravastatin, an inhibitor of hepatic hydroxymethyl glutaryl coenzyme A reductase, under various shear stresses (4.7, 9.5, 23.6, 47.3, 118.1, and 236.2 dyne/cm2) using laser diffractometry. At study entry, erythrocyte deformability under 4.7 and 9.5 dyne/cm2 shear stress, which is actually observed in human vessels, was reduced compared with that in 20 age-matched normocholesterolemic subjects and was inversely correlated with serum cholesterol and low-density lipoprotein (LDL) cholesterol. Pravastatin therapy for 1 year, which reduced serum cholesterol from 288 +/- 28 to 223 +/- 20 mg/dL, significantly improved erythrocyte deformability by approximately 20%. There was a significant relation between the improvement of erythrocyte deformability and the reduction of serum cholesterol or LDL cholesterol. The results suggest that erythrocyte deformability is reduced in hypercholesterolemic patients, and that long-term cholesterol-lowering therapy can improve reduced erythrocyte deformability, which may contribute to the improvement of organ perfusion.

Management of high serum cholesterol and related disorders in patients at risk for coronary heart disease

Cholesterol lowering has been shown to be of benefit in reducing the risk of coronary heart disease (CHD) in both patients with established CHD (secondary prevention) and those without (primary prevention). In secondary prevention trials, moderate cholesterol lowering reduced the rate of new events and decreased both morbidity and mortality from cardiovascular disease. In primary prevention, a reduction of cholesterol by 20% has produced a 31% reduction in recurrent coronary morbidity, a 33% reduction in coronary mortality, and 22% less total mortality. The target of therapy is low-density lipoprotein (LDL) cholesterol: in patients with established CHD, goal LDL is < or = 100 mg/dL. In high-risk patients without established CHD, the target goal for LDL cholesterol is < or = 130 mg/dL. Nondrug measures, bile acid sequestrants, nicotinic acid, and 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors all play important roles in cholesterol-lowering therapy.

Healthcare decisions and product labeling: results of a consumer comprehension study of prototype labeling for proposed over-the-counter cholestyramine

This study was designed to determine whether randomly selected subjects could comprehend prototype consumer-oriented package labeling and inserts for over-the-counter cholestyramine, a nonsystemic lipid-lowering agent. The primary messages communicated in the label were that consumers should see their doctor before taking cholestyramine and should read the full package insert. In addition, the label communicated indication, dosage, and preparation, as well as key warnings about use with other medications. The insert reinforced the message about seeing the doctor before taking cholestyramine and before taking concurrent medications, further explained the purpose of the drug and its correct use, and provided information about the two types of cholesterol, risk factors for heart disease, and the importance of diet and exercise. A total of 1,806 randomly selected subjects were interviewed in their homes in 40 geographic regions. After examining the product container with one of the three labels being tested, they were given a questionnaire to test their understanding of the label communication points. They were then asked to read the package insert and tested on their understanding of the messages it communicated. Responses were analyzed by gender, age, and education level, as well as by label format. For the education-level subgroup analysis, the high-school-nongraduate group was supplemented by 419 subjects, for a total of 2,225 subjects. Statistical analyses were performed on completed questionnaires by an independent data analysis company. The net correct response to the two primary communication objectives was 99% among the total population. Responses to questions addressing the use of concurrent medications; types of cholesterol; purpose, dosage, and preparation of the medication; and diet and exercise were also clearly understood. This study showed a high level of comprehension of the purpose and correct use of cholestyramine among both high-school graduates and nongraduates.

Current status of cholesterol treatment in the community: the Minnesota Heart Survey

There is a consensus on the importance of lowering blood cholesterol in individuals and populations. To determine trends in the detection and treatment of elevated cholesterol, a series of studies known as the Minnesota Heart Survey evaluated cardiovascular disease, risk, and health behavior among adults in the upper Midwest between 1980 and 1992. Over 25,000 adult residents of large and small communities were surveyed for information on risk factors and health habits, including status of cholesterol detection and treatment. During those years, population levels of blood cholesterol declined significantly for both men and women, largely as the result of changes in diet. Levels of clinical detection of hypercholesterolemia, initially low, also rose. However, subjects who had been informed that they had increased lipids reported that recommendations from their physicians for dietary therapy declined, while recommendations for weight loss increased during the survey period. Medication use for elevated blood cholesterol, always low, rose slightly, but many subjects discontinued medications due to side effects, the perception that their cholesterol was controlled, lack of perceived benefit, or cost. A total of 274 primary care physicians were also surveyed. Physicians reported that they screen more frequently than in the past and initiate drug therapy at a lower threshold. Despite improving trends in detection, treatment, and follow-up for elevated blood cholesterol in the general population, > 50% of U.S. citizens are still unaware of their elevated cholesterol levels and a growing segment of the population that has been identified as having elevated blood cholesterol remains untreated. Dietary therapy needs to be better utilized. Physicians also need to educate their patients about the importance of maintaining desirable cholesterol levels and to encourage compliance with medications for those who require them.

Adults aged 20 and older should have their cholesterol measured

The guidelines of the National Cholesterol Education Program recommend that adults > or = 20 years of age should have their total and high-density lipoprotein cholesterol measured. This recommendation, which has been endorsed by representatives of > 40 medical and health organizations, is based on a large and diverse body of scientific evidence derived from animal, pathologic, genetic, biochemical, metabolic, and epidemiologic studies and clinical trials. Elevated cholesterol levels raise the risk of coronary heart disease (CHD) in men and women and in younger and older adults. Recent clinical trials have confirmed that cholesterol lowering reduces CHD morbidity and mortality and total mortality, without an increase in noncardiovascular mortality, in patients with and without CHD. Measuring cholesterol levels in adults > or = 20 years of age is necessary to provide an accurate assessment of CHD risk to an individual; to identify individuals who should lower their cholesterol levels, using diet and lifestyle changes as the primary treatment; and to reinforce population recommendations. Atherosclerosis begins early in life, and cholesterol levels in young adults predict CHD risk 30-40 years later. Cholesterol measurement can be used to motivate lifestyle changes that will reduce the long-term risk for CHD. Waiting until mid-life to find an elevated cholesterol loses a significant portion of the benefit. Cholesterol is a CHD risk factor in women and older adults, and recent trials show significant CHD risk reduction in these groups. While drug treatment is properly directed to patients with high CHD risk, in whom drugs are cost-effective, cholesterol measurement and lifestyle-based cholesterol lowering are necessary on a broader scale to reduce long-term CHD risk in adults aged > or = 20 years.