Use of combined diet and colestipol in long-term (7--7 1/2 years) treatment of patients with type II hyperlipoproteinemia

Atherosclerosis: Making a U Turn

The development of potent cholesterol-reducing medications in the last decade of the twentieth century has altered the approach to prevention and treatment of cardiovascular disease (CVD). Initial experience with statins, and more recently with the addition of PCSK9 inhibitors, has proven that human CVD, like that in animal models, can be halted and regressed. Available clinical data show that the lower the achieved level of low-density lipoprotein cholesterol, the greater the regression of disease. Investigative studies are now aimed to understand those factors that both accelerate and impede this healing process. Some of these are likely to be modifiable, and the future of atherosclerotic CVD treatment is likely to be early screening, use of measures to repair atherosclerotic arteries, and prevention of most CVD events.

Relationship Between Xanthelasma Palpebrarum and Hyperlipidemia

BACKGROUND

Xanthelasma palpebrarum is a common periorbital lesion that occurs in middle-aged woman. Dyslipidemia was strongly associated with the occurrence of xanthelasma. Different treatment methods for xanthelasma were applied with comparable results.

MATERIALS AND METHODS

This was a retrospective chart review series performed at a single institute. The surgical pathology of 69 patients who received surgical excision from 1994 to 2012 was obtained. In addition, International Classification of Diseases, Ninth Revision, Clinical Modification code of xanthelasma (374.51) of 44 patients who underwent nonsurgical treatment at an outpatient department was acquired from 2006 to 2012. The serum lipid levels, comorbidities, recurrence, and treatment methods were obtained and analyzed with Statistical Analysis System (SAS) 9.4.

RESULTS

Of a total of 113 identified patients, 50 had lipid profile data. Of these 50 patients, 25 (50%) had dyslipidemia, which is higher than general population in Taiwan. The recurrence rate was 17.5%, and there was no statistical difference in the recurrence rate between the different treatment methods.

CONCLUSIONS

Xanthelasma was found to be associated with dyslipidemia. Thus, we recommend patients with xanthelasma to check their lipid profile and receive diet control and lipid-lowering medications for lipid abnormalities.

Dietary interventions (plant sterols, stanols, omega-3 fatty acids, soy protein and dietary fibers) for familial hypercholesterolaemia

BACKGROUND

A cholesterol-lowering diet and several other dietary interventions have been suggested as a management approach either independently or as an adjuvant to drug therapy in children and adults with familial hypercholesterolaemia (FH). However, a consensus has yet to be reached on the most appropriate dietary treatment. Plant sterols are commonly used in FH although patients may know them by other names like phytosterols or stanols.

OBJECTIVES

To examine whether a cholesterol-lowering diet is more effective in reducing ischaemic heart disease and lowering cholesterol than no dietary intervention in children and adults with familial hypercholesterolaemia. Further, to compare the efficacy of supplementing a cholesterol-lowering diet with either omega-3 fatty acids, soya proteins, plant sterols or plant stanols.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Inborn Errors of Metabolism Trials Register, which is compiled from electronic searches of the Cochrane Central Register of Controlled Trials (CENTRAL) (updated with each new issue of The Cochrane Library), quarterly searches of MEDLINE and the prospective handsearching of one journal - Journal of Inherited Metabolic Disease. Most recent search of the Group's Inborn Errors of Metabolism Trials Register: 22 August 2013. We also searched PubMed to 05 February 2012.

SELECTION CRITERIA

Randomised controlled trials, both published and unpublished, where a cholesterol-lowering diet in children and adults with familial hypercholesterolaemia has been compared to other forms of dietary treatment or to no dietary intervention were included.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the trial eligibility and risk of bias and one extracted the data, with independent verification of data extraction by a colleague.

MAIN RESULTS

In the 2014 update of the review, 15 trials have been included, with a total of 453 participants across seven comparison groups. The included trials had either a low or unclear risk of bias for most of the parameters used for risk assessment. Only short-term outcomes could be assessed due to the short duration of follow up in the included trials. None of the primary outcomes, (incidence of ischaemic heart disease, number of deaths and age at death) were evaluated in any of the included trials. No significant differences were noted for the majority of secondary outcomes for any of the planned comparisons. However, a significant difference was found for the following comparisons and outcomes: for the comparison between plant sterols and cholesterol-lowering diet (in favour of plant sterols), total cholesterol levels, mean difference 0.30 mmol/l (95% confidence interval 0.12 to 0.48); decreased serum LDL cholesterol, mean difference -0.60 mmol/l (95% CI -0.89 to -0.31). Fasting serum HDL cholesterol levels were elevated, mean difference -0.04 mmol/l (95% CI -0.11 to 0.03) and serum triglyceride concentration was reduced, mean difference -0.03 mmol/l (95% CI -0.15 to -0.09), although these changes were not statistically significant. Similarly, guar gum when given as an add on therapy to bezafibrate reduced total cholesterol and LDL levels as compared to bezafibrate alone.

AUTHORS' CONCLUSIONS

No conclusions can be made about the effectiveness of a cholesterol-lowering diet, or any of the other dietary interventions suggested for familial hypercholesterolaemia, for the primary outcomes: evidence and incidence of ischaemic heart disease, number of deaths and age at death,due to the lack of data on these. Large, parallel, randomised controlled trials are needed to investigate the effectiveness of a cholesterol-lowering diet and the addition of omega-3 fatty acids, plant sterols or stanols, soya protein, dietary fibers to a cholesterol-lowering diet.

Combination drug-diet therapies for dyslipidemia

Expense, high drug dose, and low compliance to strict dietary therapies are current issues surrounding modern drug- and diet-based lipid-lowering approaches. Furthermore, variable patient outcomes and suboptimal response to both drug and diet therapies are increasingly evident. Therefore, the question arises as to whether more emphasis should be placed on combination diet/drug therapies to reduce cholesterol levels in patients who respond suboptimally to diet and drug monotherapies. Although considerable research has explored multidrug combination therapies, combination drug/diet therapies receive less attention. However, combined drug/diet approaches may reduce the number of drug prescriptions, the progressive increase in "optimal" drug dosage, and costs associated with pharmaceutical disease management. Future research priorities in drug/diet therapeutic approaches should not only emphasize the discovery of novel combinations but also should address potential safety issues prior to wide-scale acceptance in clinical practice. Accordingly, this review will assess current limitations associated with both drug and diet lipid-lowering therapies and explore the potential of combination drug/diet therapies in the treatment of dyslipidemia.

Dietary treatment for familial hypercholesterolaemia

BACKGROUND

A cholesterol-lowering diet and several other dietary interventions have been suggested as a management approach either independently or as an adjuvant to drug therapy in children and adults with familial hypercholesterolemia. However, a consensus has yet to be reached on the most appropriate dietary treatment.

OBJECTIVES

To examine whether a cholesterol-lowering diet is more effective in reducing ischaemic heart disease and lowering cholesterol than no dietary intervention in children and adults with familial hypercholesterolaemia. Further, to compare the efficacy of supplementing a cholesterol-lowering diet with either omega-3 fatty acids, soya proteins, plant sterols or plant stanols.

SEARCH STRATEGY

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Inborn Errors of Metabolism Trials Register.Most recent search of the Group's Inborn Errors of Metabolism Trials Register: 09 October 2009.We also searched PubMed till 01 June 2008.

SELECTION CRITERIA

Randomised controlled trials, both published and unpublished, where a cholesterol-lowering diet in children and adults with familial hypercholesterolaemia has been compared to other forms of dietary treatment or to no dietary intervention were included.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the trial eligibility and methodological quality and one extracted the data, with independent verification of data extraction by a colleague.

MAIN RESULTS

In the present update, four new trials have been added making eleven trials with a total of 331 participants eligible for inclusion. Only short-term outcomes could be assessed due to the short duration of follow up in the included studies. None of the primary outcomes, (incidence of ischaemic heart disease, number of deaths and age at death) were evaluated in any of the included studies. No significant difference was noted for the majority of secondary outcomes for any of the planned comparisons. However, a significant difference was found only for the following comparison and outcome: total cholesterol levels for the comparison between plant sterols and cholesterol-lowering diet, mean difference 0.70 (95% confidence interval 0.19 to 1.21).

AUTHORS' CONCLUSIONS

No conclusions can be made about the effectiveness of a cholesterol-lowering diet, or any of the other dietary interventions suggested for familial hypercholesterolaemia, due to the lack of adequate data. Large, parallel, randomised controlled trials are needed to investigate the effectiveness of a cholesterol-lowering diet and the addition of omega-3 fatty acids, plant sterols or stanols, soya protein to a cholesterol-lowering diet.

The Importance of Managing Hypertension and Dyslipidemia to Decrease Cardiovascular Disease

BACKGROUND

Clinical management of two key modifiable risk factors for cardiovascular disease (CVD), hypertension and dyslipidemia, has evolved considerably over the past 40 years, in terms of the focus of therapy, available pharmacologic agents, and therapeutic targets.

MATERIALS AND METHODS

A brief review of the epidemiology of hypertension and hyperlipidemia and of controlled clinical trials of pharmacologic therapy of these conditions in decreasing cardiovascular events is presented.

RESULTS

Risk factors for CVD generally do not occur in isolation, and the co-occurrence of hypertension and dyslipidemia, with or without other additional risk factors, greatly increases the risk of CVD. Clinical trials performed in the last 40 years have demonstrated the clinical benefit of treating hypertension and dyslipidemia. Recent trials have shown that intensive, early management of these risk factors provide the greatest clinical benefits. Emerging evidence suggests that lipid management provides clinical benefit in patients at high risk of CVD, regardless of their baseline cholesterol levels, and that lipid-lowering with statin therapy provides additional benefits over antihypertensive therapy alone in high-risk patients with hypertension. It has become evident that the most effective means of reducing CVD risk is the simultaneous management of all modifiable risk factors. Treatment of an individual risk factor can reduce CVD events by approximately 30%, whereas treatment of multiple risk factors can reduce the risk of CVD by more than 50%. However, a large number of patients are not treated or receive suboptimal treatment.

CONCLUSIONS

Overwhelming controlled clinical trial evidence supports the clinical benefit of treating hypertension and hypercholesterolemia. Fixed-dose combination medications for hypertension, and integrative combination therapies containing antihypertensive and lipid-lowering medications in a single pill contribute to better risk factor management with the potential for greater adherence and improved clinical outcomes.

Effect of concomitant colestipol hydrochloride administration on the bioavailability of diltiazem from immediate- and sustained-release formulations

Effects of concomitant colestipol administration on plasma concentrations of diltiazem and desacetyldiltiazem from immediate-release (IR) and sustained-release (SR) formulations were assessed in two studies. In the first study, 12 subjects received 120-mg diltiazem hydrochloride (diltiazem) SR capsules or 120-mg diltiazem IR tablets administered alone and in combination with colestipol hydrochloride (colestipol). Following concomitant administration of SR diltiazem with colestipol, AUC(0-infinity ) and C(max), respectively, were 22 and 36% less, and were 27 and 33% lower for IR diltiazem. In the second study, subjects received 120-mg diltiazem SR capsules at staggered times, without colestipol, 1 h prior to or 4 h following multiple doses of colestipol. A 17% decrease in AUC(0-infinity ) was observed when diltiazem was taken 1 h before colestipol was given, and a 22% decrease when diltiazem was taken 4 h after colestipol, relative to diltiazem SR alone. C(max) values were similarly decreased. Results from these two studies show that colestipol can cause a significant decrease in diltiazem absorption from both IR and SR dosage forms. Staggering the administration of colestipol and diltiazem SR did not blunt this effect, indicating that concomitant administration of diltiazem and colestipol should be used with caution, and that the efficacy of diltiazem should be monitored to assure adequate dosing.

Dietary treatment for familial hypercholesterolaemia

BACKGROUND

Familial hypercholesterolaemia is an inherited disorder characterised by a raised blood cholesterol, the presence of xanthomatosis and premature ischaemic heart disease. The aim of treatment is the reduction of blood LDL cholesterol concentrations in order to reduce the risk of ischaemic heart disease. Current treatment is based on a cholesterol lowering diet alone or in combination with drug therapy. Many of the drugs found to be effective in treating adults with this disease are not licensed for use in children, therefore diet is the main treatment of children with familial hypercholesterolaemia. In addition to the cholesterol-lowering diet, several other dietary interventions have been suggested and consensus has yet to be reached on the most appropriate dietary treatment for children and adults with familial hypercholesterolaemia.

OBJECTIVES

To examine the evidence that in children and adults with familial hypercholesterolaemia, a cholesterol lowering diet is more effective at lowering cholesterol and reducing incidence of ischaemic heart disease than no intervention or than other dietary interventions.

SEARCH STRATEGY

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Trials Register, a specialist trials register which comprises references identified from comprehensive electronic database searches, handsearching relevant journals and handsearching abstract books of conference proceedings. Additional studies were identified from handsearching the Journal of Inherited Metabolic Disease (from inception, 1978 to 2000) and from the reference lists of identified studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs), both published and unpublished, where a cholesterol lowering diet in children and adults with familial hypercholesterolaemia has been compared to other forms of dietary treatment or to no dietary intervention. Trials which include patients with familial hypercholesterolaemia alongside patients with non-familial hypercholesterolaemia were only included if the group of familial patients was well defined and the results for these patients were available.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed the trial eligibility and methodological quality and one reviewer extracted the data, with independent verification of data extraction by a colleague.

MAIN RESULTS

Only short term outcomes could be assessed in this review due to the length of the five eligible studies. Compliance to treatment, quality of life, mortality and evidence of ischaemic or atheromatous disease were not assessed in the studies identified. No differences were found between the cholesterol-lowering diet and all other diets for all of the short term outcomes assessed.

REVIEWER'S CONCLUSIONS

No conclusions can be made about the effectiveness of the cholesterol-lowering diet, or any of the other dietary interventions suggested for familial hypercholesterolaemia, due to the lack of adequate data. A large, parallel, randomised controlled trial is needed to investigate the effectiveness of the cholesterol-lowering diet and other dietary interventions for FH. It is also possible that data from trials including subjects with both familial and non-familial hypercholesterolaemia could alter the results of future updates of this review and until further evidence is available current dietary treatment of FH should continue to be observed and monitored with care.

The secondary prevention of coronary artery disease

Randomized clinical trials demonstrate the efficacy of medical secondary prevention in coronary disease patients. The magnitude of risk reduction with exercise, diet, lipid modification, and smoking cessation is similar to other medical therapies for coronary disease such as aspirin, beta blockers, as well as coronary bypass surgery, (Table VI) In contrast to these therapies, however, secondary prevention stabilizes angiographic progression in about 50% of patients and induces regression in about 25% of patients. Both symptoms and perceived quality of life also are beneficially altered by secondary prevention programs, although possibly not by the magnitude reported for bypass surgery. These clinical trial results have led the American Heart Association, and the American College of Cardiology to strongly endorse secondary prevention. A reasonable projection based on these clinical trial data is that widespread use of these recommendations in the 12 million established coronary disease patients would significantly reduce coronary mortality and morbidity.

Specific reduction of plasma large, light low-density lipoprotein by a bile acid sequestering resin, cholebine (MCI-196) in type II hyperlipoproteinemia

The effect of a bile acid sequestrant, cholebine (3 g/day), on plasma lipoprotein subfractions was investigated in 16 patients with type II hyperlipoproteinemia. Activities of low density lipoprotein (LDL)-receptor and activities of lecithin:cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP) were assayed to address the mechanism of cholebine-induced changes in plasma lipoprotein subfractions. Twelve weeks of treatment with cholebine reduced plasma levels of total cholesterol (TC) and LDL-cholesterol (C) by 8.3 +/- 8.1% (mean +/- S.D.) and 14.4 +/- 11.9%, respectively (P < 0.001), but did not affect plasma levels of high density lipoprotein (HDL)-C. Cholebine significantly reduced plasma levels of LDL1-C (1.019 < d < 1.045) by 22.9 +/- 18.9% (P < 0.001) but did not affect plasma levels of very low density lipoprotein (VLDL)-C, intermediate density lipoprotein (IDL)-C, LDL2-C (1.045 < d < 1.063), HDL2-C, and HDL3-C (d > 1.125). Gradient polyacrylamide gel electrophoresis (PAGE) revealed that cholebine reduced large LDL in plasma but had almost no effects on small LDL and HDL subfractions. Cholebine did not alter the activities of LCAT and CETP. LDL-receptor activities of cultured lymphocytes negatively correlated with the reduction in plasma levels of LDL-C (r = -0.500, P < 0.05), IDL-C (r = -0.581, P < 0.02), and LDL1-C (r = -0.610, P < 0.01), respectively. Thus, cholebine seems to reduce further the plasma levels of IDL and large, light LDL in patients with lower LDL-receptor activities. We conclude that cholebine only reduces plasma levels of large, light LDL. This may be due to the stimulation of hepatic LDL-receptor activity.

Assessing the independent effect of dietary counseling and hypolipidemic medications on serum lipids

Determination of changes in total cholesterol (TC) and triglyceride (TG) levels has focused primarily on hypolipidemic drug effects. Changes resulting from dietary effect alone versus diet and drug effect have not yet been fully established. Seventy subjects were enrolled into four treatment groups to determine the impact of diet and drug effect upon TC and TG. Group 1 (n = 28) served as the control group and received no dietary counseling or drug therapy. Group 2 (n = 22) received dietary counseling. Group 3 (n = 7) underwent dietary counseling for six months and drug therapy for eighteen months. Subjects in groups 1-3 were monitored for eighteen months. Patients in group 4 (n = 13) were followed up for thirty-six months. No intervention occurred during the first eighteen months, and hypolipidemic medications were used during the second eighteen-month period. Subjects in groups 1 and 4 received no specific dietary counseling and demonstrated no significant improvement over the course of the study. Patients in groups 2 and 3 showed significant reductions in both TC and TG. The improvement in TC seen for patients in group 3 was reduced after dietary counseling ceased. Dietary intervention is necessary if patients are to statistically significantly reduce TC and TG levels. Drug therapy demonstrated the expected reductions in both TC and TG but did not statistically significantly lower lipid levels without concomitant dietary counseling. When dietary counseling and hypolipidemic medications are used together, reductions in TC and TG values are even greater than those seen with dietary effect alone. Diet control alone appears to significantly reduce TC and TG levels, resulting in reduced need for antianginal medications.

Age-related changes affecting atherosclerotic risk. Potential for pharmacological intervention

The incidence of cardiovascular diseases that are related to the atherosclerotic process increases exponentially with age. Organ lesions, the clinical manifestation of atherosclerotic disease, are late events due to complications in the plaque (ulceration, thrombosis, calcification) which are the result of an increased vulnerability to disruption of a previously stable plaque. The higher incidence of age-related clinical events could be explained by a rising sensitivity of plaques to destabilising factors, both parietal and humoral. The increased probability that a plaque in an elderly patient will became vulnerable could be related to those destabilising factors that significantly increase with aging, such as advanced glycation end-products. For these reasons, it seems most important that the analysis of these age-related destabilising factors, rather than those factors that promote the development of early atherosclerotic plaques, should be undertaken. Taking the point of view of a pharmacological intervention, this should eventually lead to a more complete understanding of this process.

Treating hyperlipidemia in the elderly

BACKGROUND

Determination of the effects of dietary modification and hyperlipidemic medications in the elderly (> sixty-five years of age) patient has not been significantly investigated to date despite knowledge that elevated cholesterol (TC) and triglyceride (TG) levels increase the risk of coronary artery disease (CAD).

METHODS

Twenty-seven individuals were placed into one of three treatment groups and longitudinally followed up to examine the effects of diet and hyperlipidemic medications on TC and TG levels. Group 1 (n = 14) received neither dietary nor drug therapy. Group 2 (n = 9) received dietary counseling without concomitant hyperlipidemic medications. Subjects in group 3 (n = 4) underwent dietary instruction for six months and hyperlipidemic medication(s) for eighteen months.

RESULTS

Subjects in group 1 demonstrated a statistical increase in TC (P < or = 0.001) during the study. Patients in groups 2 (P < or = 0.001) and 3 (P < or = 0.05) demonstrated statistical improvement in TC reduction during dietary counseling. The effect on TC was blunted in group 3 after dietary counseling was discontinued. Reductions in TG levels were significant (P < or = 0.001) only for patients in group 2.

CONCLUSION

Elderly individuals were able to significantly reduce both TC and TG levels by dietary modification alone. Minimal improvement was seen with the addition of hyperlipidemic medications.

Dyslipidemia and coronary artery disease

Genetically determined and metabolically induced disturbances in lipid metabolism, as manifested in several types of dyslipidemia, have been shown to be causally related to the development of coronary artery disease (CAD). A diversity of clinical and angiographic studies has been made to evaluate the linkage between plasma lipid-control therapy in the development of initial and recurrent cardiovascular events. The plan of treatment invariably begins with a low-fat, low-cholesterol diet before initiation of drug therapy. However, many patients have difficulty in adhering to the low-fat diet. Fortunately, metabolic studies show that foods which contain fats rich in stearic (saturated) and oleic (monounsaturated) fatty acids may be given in limited amounts to boost patients' compliance to a low-fat diet and to prevent their blood lipids from rising to abnormal levels. A bile acid sequestrant (cholestyramine or colestipol) is the first-line drug for control of hypercholesterolemia. Either gemfibrozil or gemfibrozil plus niacin is prescribed to raise high-density lipoprotein (HDL) levels of CAD patients. Approval of two HMG CoA reductase inhibitors, pravastatin and simvastatin, by the FDA gives physicians the additional flexibility of employing a single or a combination drug therapy for optimal control of dyslipidemia. The association of low serum cholesterol level (< 160 mg/dl) with increase in noncardiac mortality has prompted health professionals to consider modifying the universal screening and treatment of serum cholesterol in children and young women and to use hypolipidemic drugs in patients judiciously.

Effect of cholesterol reduction by simvastatin on progression of coronary atherosclerosis: Design, baseline characteristics, and progress of the Multicenter Anti-Atheroma Study (MAAS)

The Multicenter Anti-Atheroma Study (MAAS) is a 2 + 2-year, placebo-controlled trial to evaluate the effect of simvastatin, a 3-hydroxy-3-methylglutaryl coenzyme a (HMG-CoA) reductase inhibitor, on progression and regression of coronary atherosclerosis in patients with established coronary artery disease. This paper describes the aims, methodology, and baseline data. Patients with at least two coronary segments visibly involved with atherosclerosis, in whom an angiogram was carried out according to the standards required for quantitative analysis, were selected provided that the serum total cholesterol was between 5.5 and 8.0 mmol/L and fasting triglycerides were lower than 4 mmol/L. Between march 1988 and October 1989, 383 eligible patients of both sexes aged 30-67 years were randomized in 11 European clinics. Patients received either 20 mg oral simvastatin or placebo daily for 2 years in addition to dietary counseling. The primary outcome measures are the change in the mean absolute width and in the mean of the minimal width of segments analyzed quantitatively by coronary angiography performed before and after 2 and 4 years of trial medication. To this end, at least 5 coronary artery segments are analyzed in each angiogram using matched view. The 2-year analysis was completed on 89% of eligible patients in February 1992. The trial was initially designed with a 2-year treatment period. To allow for the possibility to extend this, the decision was taken to keep all patients on the original medication allocation until all 2-year angiograms had been analyzed. Based on a predefined decision rule, an independent committee then recommended extension of treatment with another 2 years, to be concluded by a third angiogram. Of the patients enrolled initially, 81% continued. Four-year follow-up will be completed late 1993 and final results are expected mid 1994.

Arteriographic view of treatment to achieve regression of coronary atherosclerosis and to prevent plaque disruption and clinical cardiovascular events

Lipid-lowering therapy, as assessed by angiography, clearly benefits the arterial disease process. For example, among intensively treated patients in FATS the frequency of definite progression per lesion at risk was reduced by 75% among mild and moderate lesions, which form the great preponderance of the lesion population. Regression frequency per lesion was more than doubled by intensive therapy in mild and moderate subgroups and quadrupled in the subgroup with severe lesions. Clinical events were reduced by 73%. This was clearly due to a 15-fold reduction in the likelihood that a mildly or moderately diseased arterial segment would undergo abrupt and substantial progression to a severe lesion at the time of the clinical event. It has been shown that the process of plaque fissuring, leading to plaque disruption, thrombosis, and clinical coronary events, is predicted by the size of the plaque core lipid pool and the abundance of lipid-laden macrophages in its fibrous cap. Experimentally, lipid lowering therapy decreases the number of lipid-laden intimal macrophages and more slowly depletes core cholesteryl ester deposits. Thus the composite of new and previously published data presented here supports the idea that lipid-lowering therapy selectively lipid-depletes (causes regression of) those fatty lesions containing a large lipid core and abundant intimal foam cells. By doing so, these lesions, which are most vulnerable to fissuring, are rendered much more stable and the clinical event rate is accordingly decreased.

Improved stenosis geometry by quantitative coronary arteriography after vigorous risk factor modification

This study is a randomized, controlled, blinded, arteriographic trial to determine the effects of a low-cholesterol, low-fat, vegetarian diet, stress management and moderate aerobic exercise on geometric dimensions, shape and fluid dynamic characteristics of coronary artery stenoses in humans. Complex changes of different primary stenosis dimensions in opposite directions or to different degrees cause stenosis shape change with profound effects on fluid dynamic severity, not accounted for by simple percent narrowing. Accordingly, all stenosis dimensions were analyzed, including proximal, minimal, distal diameter, integrated length, exit angles and exit effects, determining stenosis shape and a single integrated measure of stenosis severity, stenosis flow reserve reflecting functional severity. In the control group, complex shape change and a stenosis-molding characteristic of statistically significant progressing severity occurred with worsening of stenosis flow reserve. In the treated group, complex shape change and stenosis molding characteristic of significant regressing severity was observed with improved stenosis flow reserve, thereby documenting the multidimensional characteristics of regressing coronary artery disease in humans.

Factors influencing the formation of new human coronary lesions: age, blood pressure, and blood cholesterol

BACKGROUND

The Cholesterol Lowering Atherosclerosis Study, a controlled angiographic trial, has reported that new native coronary artery lesions are significantly reduced by aggressive blood lipid lowering therapy with colestipol plus niacin. To study factors relevant to primary atherosclerosis prevention, we have conducted an epidemiologic analysis of new native coronary lesion formation in placebo-treated patients.

METHODS

Univariate and multivariate logistic regression procedures were used to examine age at entry into the study, number of years since bypass, body weight, diastolic and systolic blood pressure, plasma total cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, non-HDL-cholesterol, and apolipoproteins A-I,B, and C-III.

RESULTS

Significant univariate protective factors were older age (P less than .006), reduction of total plasma cholesterol (P less than .040), and systolic (P less than .024) and diastolic (P less than .022) blood pressure. Significant multivariate protective factors were older age (P less than .005) and reduction in systotic blood pressure (P less than .021). Blood pressure effects were not associated with use of specific antihypertensive agents.

CONCLUSIONS

These data provide additional support for the control of hypertension and reduction of blood cholesterol level for primary and secondary ischemic heart disease prevention. They also indicate the existence of a population at high risk for early coronary lesion formation and the need for improved means to identify such individuals prior to the onset of clinical manifestations of ischemic heart disease.

A comparative review of the adverse effects of treatments for hyperlipidaemia

Various lipid-lowering drugs have been shown to reduce serum cholesterol and serum triglycerides effectively. In view of trials indicating that lipid-lowering drugs may reduce cardiac morbidity and mortality but not the overall mortality in the study group, increased attention must be focused on potential harmful side effects during treatment with these agents. The adverse effects of many of the principal drugs in this category are discussed. Gastrointestinal symptoms, usually self-limited and reversible, are the most common side effects. Potential harmful adverse effects include drug interactions (cholestyramine), myopathy and hepatic injury (HMG-CoA reductase inhibitors), and increased gallstone formation and ventricular arrhythmias (clofibrate). Not all lipid-lowering drugs have been studied adequately on a long term basis, so that medications given for an indefinite period must be reevaluated frequently. However, there are several agents that lower serum lipid levels effectively and that have been used for more than 20 years without serious side effects.

Effects of therapy with diet and simvastatin on atherosclerosis in hypercholesterolemic patients

We evaluated the effect of cholesterol reduction on atherosclerotic coronary artery lesions using diet and simvastatin, a potent HMG CoA reductase inhibitor. Fifteen subjects aged 28-69 years (mean 44), each of whom demonstrated significant (greater than 50%) narrowing of a coronary artery and a baseline cholesterol level greater than 278 mg/dl, were studied. Coronary arteriography was performed prior to and after 20 +/- 2.5 months of therapy. A 42% reduction in total serum cholesterol, a 52% reduction in LDL cholesterol, and an 87% increase in the HDL/LDL cholesterol ratio (p less than 0.01) were achieved. Pretreatment and posttreatment angiograms were reviewed by three experienced angiographers with temporal order masked. Improvement in the overall status of coronary atherosclerotic lesions was demonstrated in two patients (13%), while deterioration occurred in one patient (7%). No overall change was found in the remaining 12 patients (80%). We conclude that a cholesterol-lowering regimen using a nonatherogenic diet and simvastatin therapy may at least stabilize coronary atherosclerosis.

A new method of scoring coronary angiograms to reflect extent of coronary atherosclerosis and improve correlation with major risk factors

We developed a new angiographic score of the extent of coronary disease (extent score), which we compared with conventional stenosis and vessel scores that emphasize the severity of stenosis. Scores were determined in 132 patients (29 women, 103 men with a mean age of 55 +/- 10 years) who underwent elective coronary angiography. Risk factors were more closely related to the extent score than to either the stenosis or vessel scores (Total R2 = 0.35 versus 0.28 (p less than 0.001) and 0.25 (p less than 0.001), respectively). The extent score was more closely related to age (r = 0.30, p less than 0.05), than was either stenosis (r = 0.21 ns) or vessel score (r = 0.26, p less than 0.05). Apolipoprotein B was the strongest predictor of both extent and stenosis scores but was more closely related to the extent score (r = 0.36, p less than 0.05), even after correction for age and gender. This new angiographic score that assesses the extent of coronary disease is simple to perform and correlates better with age and lipoprotein risk factors than conventional scores do.

Bile acid sequestrants

The bile acid sequestrants, cholestyramine and colestipol, are the drugs of choice for the treatment of patients with hypercholesterolemia caused by increases in LDL-cholesterol levels without concurrent hypertriglyceridemia (type IIA and type IIB hyperlipoproteinemia). Longitudinal clinical studies with these drugs have shown their ability to slow the progression of atherosclerosis and to limit the consequences of the disease. Bile acid sequestrants can be used with other lipid-lowering drugs such as nicotinic acid or HMG CoA reductase inhibitors, to maximize the cholesterol-lowering effects. The side effect profile of the bile acid sequestrants is tolerable, with most complaints related to effects on the gastrointestinal tract and the bulkiness of the resins.

Drug therapy and the prevention of atherosclerosis in humans

The results of the World Health Organization Cooperative Trial, the Coronary Drug Project, the Coronary Primary Prevention Trial and the Helsinki Heart Study indicate that clinical expression of coronary artery disease can be delayed with pharmacologic modification of plasma lipoproteins. Change in coronary artery disease can be semiquantitated by repeat arteriograms. Three randomized clinical trials indicate that rate of progression of atherosclerosis, as defined by arteriography, can be reduced, and existing lumen obstruction decreased. Tendon xanthomas occur in hypercholesterolemia, and reduction in xanthoma size with drug therapy suggests an improved atherosclerotic disease state. The clinician has a variety of pharmacologic therapies available. The role of bile acid-binding resins, fibric acid derivatives, hydroxymethylglutaryl coenzyme A reductase inhibitors, nicotinic acid and antioxidants is each unique. Understanding the role of lipoproteins in atherosclerosis will help in selecting the most appropriate therapy for each individual patient. Medications not designed for their lipoprotein effects can significantly alter lipoproteins. Medications, such as nonselective beta blockers, can alter low-density lipoprotein (LDL) subclass distribution with no change in LDL cholesterol content. Such changes may eradicate part of the beneficial cardiovascular effect of beta blockade therapy. In the future, therapeutic choices may depend in part on lipoprotein abnormalities such as lipoprotein (a), apolipoprotein E isoforms, hyperapobetalipoproteinemia, LDL.

Management of blood lipid abnormalities in coronary heart disease patients

Information obtained from clinical and laboratory research strongly supports a causal relationship between hyperlipidemia (dyslipidemia) and coronary heart disease (CHD), and provides an impetus to develop strategy for control of dyslipidemia. Some recent developments in the field may include the use of: (1) colestipol-niacin to control hypercholesterolemia and induce regression of coronary atherosclerosis; (2) limited amounts of foods rich in stearic or oleic fatty acids to enhance the appeal of cholesterol-lowering regimen; (3) gemfibrozil or lovastatin to inhibit cholesterol synthetic activity; and (4) gemfibrozil to raise atherosclerosis-protective plasma high-density lipoprotein levels. These and other newer developments will stimulate interest in research on dyslipidemia and its control to facilitate primary and secondary prevention of CHD.

Population strategies of cardiovascular disease prevention: scientific base, rationale and public health implications

Congruence of evidence from all medical research methodologies has established the major causal influences in cardiovascular disease. Causation thus established, epidemiological observations are the best available evidence on which to base estimates of the potential of preventive strategies. From population comparisons we learn that some countries have little cardiovascular disease; therefore, prevention is a reality. From mortality surveillance we learn that the disease processes are highly dynamic. Parallels between cardiovascular disease and major non-cardiovascular disease mortality trends suggest that they have common causes and that common preventive strategies may be effective for both. From migrant studies we learn the predominant contribution to population risk of environment and culture. From population surveys we learn that risk characteristics for cardiovascular disease are mass phenomena, therefore they require mass preventive approaches. Follow-up studies in cohorts provide evidence of the risk attributable to elevated risk characteristics and the potential for preventive strategies in high risk societies with high disease rates. Clinical trials indicate the effectiveness of interventions in high risk individuals, the relative safety of such efforts and that cardiovascular disease prevention effects emerge in a very few years. Public health trials demonstrate that communities can mount and maintain effective preventive programs and what programs work best. Studies in youth indicate that risk of adult disease starts early and that an optimal prevention program would seek to prevent elevated risk in the first place.

Effects of acipimox and cholestyramine on serum lipoproteins, non-cholesterol sterols and cholesterol absorption and elimination

The hypolipidaemic and metabolic effects of cholestyramine combined with acipimox or placebo have been evaluated in a double-blind ninety-day study in 18 patients with xanthomatous familial hypercholesterolaemia. Serum LDL-cholesterol was reduced by 35% in the cholestyramine group and 39% in the acipimoxcholestyramine group. The latter treatment increased the HDL-cholesterol level. Serum VLDL-cholesterol and triglyceride concentrations were unchanged. Cholesterol absorption efficiency was significantly reduced, and bile acid synthesis and faecal cholesterol elimination in both groups were increased. The metabolic changes were similar in the two treatment groups, but the increase in faecal neutral sterol excretion was significant only when acipimox was added. The serum cholesterol precursor sterol contents were similarly increased during the two treatments, indicating enhancement of endogenous cholesterol synthesis. The decrease in cholesterol absorption and the increase in neutral sterol excretion were more pronounced in subjects with greater than 30% than in those with less than 30% reduction in LDL-cholesterol. The changes in serum total and LDL-cholesterol levels and cholesterol metabolism were not related to apoE phenotype, but the increase in HDL-cholesterol was higher in E4 then in E3 subjects.

Therapeutic control of hyperlipidemia in the prevention of coronary atherosclerosis: a review of results from recent clinical trials

The link between elevated plasma cholesterol levels and coronary atherosclerosis is now well established. During the past decade, results from therapeutic trials indicate that control of hypercholesterolemia does result in lower cardiovascular risk. Many of these results were obtained in hypercholesterolemic, middle-aged men. Comparable data in women are not available but it is inferred that they would also benefit from cholesterol reduction. Results from the Coronary Drug Project, extended over 15 years, indicate that lipid-lowering therapy with niacin for 5 years was associated with a decrease in total mortality as well as mortality from coronary heart disease. In the studies performed for shorter periods (5 to 7 years), therapy lowered only cardiovascular morbidity and mortality but had no beneficial effect on total mortality. A reduction in cardiovascular risk begins to appear 24 to 28 months after the initiation of therapy and continues to accrue thereafter. The relatively uniform results from recent large-scale clinical trials (Lipid Research Clinics Coronary Primary Prevention Trial, Coronary Drug Project, Helsinki Heart Study) indicate that cholesterol reduction, per se, probably explains the lower cardiovascular morbidity and mortality observed in these trials. As a result of these trials, recent redefinitions of hypercholesterolemia and more aggressive treatment programs have been recommended. These guidelines stress assessment of all cardiovascular risk factors and recommend individualized care of the patient. To control hypercholesterolemia, conservative measures with diet are recommended before therapy with medication is considered. Recent clinical trial experience indicates that the clinician can have significant impact on atherosclerosis by identifying and treating patients with plasma cholesterol levels in the high-risk range.

Management of lipids in primary and secondary prevention of cardiovascular diseases

Although the frequency of cardiovascular disease is declining, it remains a major present and future threat to health in the United States. The deleterious effects of abnormal blood lipid concentrations have long been recognized, but the benefit of corrective intervention in this process has only recently been demonstrated. We review the major lipid abnormalities and the available clinical therapeutic interventions. In addition, we discuss data that address the premise that reducing low-density lipoprotein cholesterol or raising high-density lipoprotein cholesterol should decrease the progression of coronary atherosclerosis, and we summarize drug trials in which clofibrate, niacin, cholestyramine, and gemfibrozil decreased coronary heart disease events. Studies that used cholestyramine and the combination of colestipol and niacin resulted in decreased progression of coronary artery disease. On the basis of early experience with lovastatin, inhibitors of hydroxymethylglutaryl-coenzyme A reductase are likely to be effective in the treatment of hypercholesterolemia. The available information on the association of low cholesterol levels and cancer suggests that low total cholesterol is a consequence rather than a cause of carcinoma. Current data strongly support the concept of vigorous intervention directed at management of lipids, both with non-pharmacologic treatment and with drug therapy, for the primary and secondary prevention of coronary atherosclerosis.

The Cholesterol Lowering Atherosclerosis Study (CLAS): design, methods, and baseline results

The Cholesterol Lowering Atherosclerosis Study (CLAS) is a prospective, placebo-controlled, angiographic trial designed to test the hypothesis that aggressive lowering of LDL cholesterol with concomitant increase in HDL cholesterol will reverse or retard the atherosclerotic process. Specifically, CLAS was designed to determine whether combined therapy with colestipol plus niacin will produce clinically significant change in coronary, carotid, and femoral artery atherosclerosis and coronary bypass graft lesions. To this purpose, 188 subjects were randomized to diet plus drug or diet plus placebo. We report on methodological aspects of planning and evaluating this study, including the choice of the study population, procedures for recruitment, the experimental design including sample size considerations, methods for evaluating outcome, and methods for evaluating compliance to treatment. Comparison of baseline data indicated no significant differences between groups at the time of randomization. Subjects were predominantly male, Caucasian, 54 years of age, 20% above ideal weight, with normal blood pressure. The average age at bypass was 50 years. The average lipids were cholesterol (243 mg/dL), HDL (45 mg/dL), and LDL (168 mg/dL). Finally, the distribution of baseline coronary stenosis was equivalent between the two groups (average number of lesions per subject = 10.6).

Mode of action of lipid-lowering drugs

Following the recent demonstration that both cholestyramine and nicotinic acid decrease mortality from coronary heart disease, there is a new enthusiasm for hypolipidaemic therapy. The agents in current use are, however, insufficiently active or are accompanied by unacceptable side effects. An understanding of the mode of action is necessary, both to optimize treatment guidelines (e.g. regarding combination therapy or use in specific subsets of patients) and to develop new agents with preferred actions on rate-limiting steps. A reduction in LDL cholesterol concentration remains the principal desired action, although an elevation in HDL may also be beneficial. The main categories of commercially available agent comprise the anion exchange resins (inhibitors of bile acid absorption); cholesterol absorption inhibitors; fibrates (probably acting by enhancing lipoprotein lipase); and probucol (affecting LDL clearance). The most interesting of the new agents in clinical trials are the beta-hydroxy-beta-methylglutaryl-CoA reductase inhibitors, but other types of agent are at an earlier stage of evaluation, e.g. acyl-CoA: cholesterol acyltransferase inhibitors and peptide cofactors. It is not yet certain whether all the approaches to cholesterol lowering have equal validity, although an effect on biological endpoints is obtained for a variety of agents. Future evaluation will be aided by the implementation of noninvasive methods to quantify atherosclerosis and by the use of simple, 'dry-chemistry', cholesterol assays to screen populations.

Medical approaches to prevention of restenosis after coronary angioplasty

Although initial success rates for coronary angioplasty have improved, the rate of restenosis within 6 months of the procedure has persisted at 30 to 40%. The relation of restenosis to initial success, recurrence of symptoms and risk factors suggests that high grade or total lesions, long lesions, lesions in the proximal left anterior descending artery or in saphenous grafts, and the absence of intimal dissection after angioplasty are associated with an increased risk of restenosis. Unstable angina, male sex and diabetes are clinical factors associated with a greater risk of restenosis. Pathologic specimens suggest that plaque splitting and disruption are found acutely after angioplasty, but that restenosis occurs as an excessive reparative, proliferative response of smooth muscle cells leading to recurrent luminal narrowing. A prospective analysis of therapeutic interventions to prevent restenosis, such as administering antiplatelet and lipid-lowering agents, intensive diabetic therapy and administration of calcium antagonists, is proposed. Problems with timing of studies, design and sample size are considered. Current recommendations for anti-restenosis therapy include antiplatelet therapy before and after angioplasty, administration of heparin in some patients and intensive risk factor intervention for the 6 months after the procedure.

Adverse effects of hypolipidaemic drugs

Cholestyramine, colestipol, clofibrate, gemfibrozil, nicotinic acid (niacin), probucol, neomycin, and dextrothyroxine are the most commonly used drugs in the treatment of hyperlipoproteinaemic disorders. While adverse reaction data are available for all of them, definitive data regarding the frequency and severity of potential adverse effects from well-controlled trials using large numbers of patients (greater than 1000) are available only for cholestyramine, clofibrate, nicotinic acid and dextrothyroxine. In adult patients treated with cholestyramine, gastrointestinal complaints, especially constipation, abdominal pain and unpalatability are most frequently observed. Continued administration along with dietary manipulation (e.g. addition of dietary fibre) and/or stool softeners results in diminished complaints during long term therapy. Large doses of cholestyramine (greater than 32 g/day) may be associated with malabsorption of fat-soluble vitamins. Most significantly, osteomalacia and, on rare occasions, haemorrhagic diathesis are reported with cholestyramine impairment of vitamin D and vitamin K absorption, respectively. Paediatric patients have been reported to experience hyperchloraemic metabolic acidosis or gastrointestinal obstruction. Concurrent administration of acidic drugs may result in their reduced bioavailability. Serious adverse reactions to clofibrate will probably limit its role in the future. Of particular concern are ventricular arrhythmias, induction of cholelithiasis and cholecystitis, and the potential for promoting gastrointestinal malignancy which far outweigh the reported benefits in preventing new or recurrent myocardial infarction, cardiovascular death and overall death. Patients with renal disease are particularly prone to myositis, secondary to alterations in protein binding and impaired renal excretion of clofibrate. Drug interactions with coumarin anticoagulants and sulphonylurea compounds may produce bleeding episodes and hypoglycaemia, respectively. Nicotinic acid produces frequent adverse effects, but they are usually not serious, tend to decrease with time, and can be managed easily. Dermal and gastrointestinal reactions are most common. Truncal and facial flushing are reported in 90 to 100% of treated patients in large clinical trials. Significant elevations of liver enzymes, serum glucose, and serum uric acid are occasionally seen with nicotinic acid therapy. Liver enzyme elevations are more common in patients given large dosage increases over short periods of time, and in patients treated with sustained release formulations.(ABSTRACT TRUNCATED AT 400 WORDS)

Progression of coronary atherosclerotic disease assessed by cinevideodensitometry: relation to clinical risk factors

Progression of coronary artery stenosis was measured using a quantitative, computer-assisted cinevideodensitometric method in 144 arterial segments in 44 subjects undergoing coronary arteriography on two separate occasions at least 6 months apart. Projected coronary arteriograms were digitized into 512 X 512 pixel mode and percent stenosis was calculated by comparing background-corrected videodensitometric values over stenotic and normal segments. Subjects underwent repeat coronary arteriography because of worsening symptoms of angina or heart failure; subjects with renal failure, coronary artery bypass grafts or cardiac transplant were excluded. Clinical variables determined at the time of the first arteriogram included age, sex, serum cholesterol, systolic blood pressure and presence or absence of cigarette smoking, diabetes mellitus and left ventricular hypertrophy. The mean interval between arteriograms was 29.3 months. Overall progression of coronary stenosis was observed in 40 of the 44 subjects; the mean progression at 24 months was 39% (90% confidence interval, 33 to 45%) and at 36 months was 48% (40 to 56%). The degree of overall progression was related to the length of time between arteriograms (F = 5.81, p less than 0.05) and to serum cholesterol level (F = 4.37, p less than 0.05). These data indicate that using an accurate, quantitative method, it is possible to measure progression of coronary artery atherosclerosis within 2 to 3 years of the initial arteriogram. Serum cholesterol appears to be an important determinant of disease progression.

Effects of combined probucol-colestipol treatment for familial hypercholesterolemia and coronary artery disease

To evaluate the effect of hypercholesterolemic treatment on coronary artery disease in patients known to be susceptible to disease progression, 44 patients with familial hypercholesterolemia and coronary artery disease were started on a lipid-lowering diet and either probucol (1 g/day) or colestipol (30 g/day). After 5 months of monotherapy, all patients went on a regimen of diet and 2-drug therapy. To date, combination therapy has continued for 3.4 to 4.1 years, and has resulted in the following changes from baseline in mean serum lipid levels: -48.5% in total cholesterol, -53.3% in low density lipoprotein cholesterol, -30.0% in high density lipoprotein cholesterol and +14.5% in triglycerides. The reduction in low density lipoprotein cholesterol apparently improved the clinical status of these patients despite the associated drop in high density lipoprotein cholesterol. In the 19 patients who underwent coronary arteriography before admission to the study, follow-up arteriograms showed that combined treatment stabilized the progression of established lesions and prevented the formation of new ones. Side effects occurred mainly with monotherapy and during the early phase of combination therapy. Reactions included diarrhea, constipation, other vague abdominal symptoms, headache and joint stiffness. In all instances, the side effects gradually subsided after the institution of combination therapy. The combination of probucol and colestipol plus diet appears to be effective in treating most patients with familial hypercholesterolemia.

Role of risk factor management in progression and regression of coronary and femoral artery atherosclerosis

The results of 3 recently completed studies usher in a new era in the treatment of coronary atherosclerosis and its sequelae. In aggregate, these results show that reductions in low density lipoprotein (LDL) cholesterol or reductions in the ratio of total to high density lipoprotein (HDL) cholesterol by either diet or drugs or both are effective in primary and secondary prevention of coronary artery disease (CAD). In the Lipid Research Clinics' Coronary Primary Prevention Trial, reducing levels of LDL cholesterol, regardless of whether the primary intervention was diet or drug, correlated with a reduction in CAD events. In the National Heart, Lung, and Blood Institute's Type II Coronary Intervention Study, CAD progression at 5 years was inversely related to a change in the ratio of HDL cholesterol to total cholesterol. In the Leiden Intervention Trial, cessation of coronary artery atherosclerotic lesion growth correlated with the ratio of total cholesterol to HDL cholesterol. Several trials now under way will test the effects of much more substantial reductions of LDL cholesterol (up to 50%) and increments in HDL cholesterol (up to 25%) on interrupting the progression or inducing the regression of coronary artery atherosclerosis. Even small reductions in the progression of coronary artery lesions or induction of their regression should produce major reductions in morbidity and mortality from CAD. The importance of secondary prevention also extends to patients after coronary artery bypass surgery, because the likelihood of graft occlusion is likewise related to the patient's lipid profile. Further, the importance of primary prevention of atherosclerosis through modification of lipids and lipoprotein cholesterol in the first-degree relatives of young victims of atherosclerosis cannot be overemphasized.

Nutrition education for risk factor reduction and patient education: a review

Studies of adult nutrition education and counseling for weight reduction, diabetes, cancer, low-fat diets, sodium-restricted diets, and renal diets are reviewed and synthesized. Nutrition education consists of three phases: assessment or problem diagnosis, intervention, and evaluation and monitoring. This article examines the importance of accurate problem diagnosis, the use of behavioral and biological measures of nutrition education effectiveness, and the types and effects of reported strategies. In addition, the issues of maintaining behavioral changes, nutrition education providers and their training, and settings for nutrition education are discussed. Implications and suggestions for advances in practice, theory, and research in patient nutrition education are presented.

Coronary heart disease and risk factor modification. Is there a threshold?

Modification of coronary heart disease risk factors may play an important role in the control and alteration of the atherosclerotic process. The amount of modification necessary to obtain beneficial results is a controversial issue. Review of epidemiologic studies and recent arteriographic investigations allows for the approach to the issue of threshold levels of modification that may be required prior to obtaining some benefit. Serum lipoproteins appear to play a central role in the atherosclerotic risk factor relationship. On the basis of current evidence, clinical aims are suggested for coronary heart disease risk factor modification in order to assist in obtaining optimal health goals.

Diet, lipoproteins, and the progression of coronary atherosclerosis. The Leiden Intervention Trial

We studied the relation between diet, serum lipoproteins, and the progression of coronary lesions in 39 patients with stable angina pectoris in whom coronary arteriography had shown at least one vessel with 50 per cent obstruction before intervention. Intervention consisted of a two-year vegetarian diet that had a ratio of polyunsaturated to saturated fatty acids of at least 2 and that contained less than 100 mg of cholesterol per day. Dietary changes were associated with a significant increase in linoleic acid content of cholesteryl esters and a significant lowering of body weight, systolic blood pressure, serum total cholesterol, and the ratio of total to high-density lipoprotein (total/HDL) cholesterol. Angiographic examination was performed after 24 months; angiograms were assessed visually (with blinding) and by computer-assisted image analysis. Both types of assessment indicated progression of disease in 21 of 39 patients but no lesion growth in 18. Coronary lesion growth correlated with total/HDL cholesterol (r = 0.50, P = 0.001) but not with blood pressure, smoking status, alcohol intake, weight, or drug treatment. Disease progression was significant in patients who had values for total/HDL cholesterol that were higher than the median (greater than 6.9) throughout the trial period. No coronary-lesion growth was observed in patients who had lower values for total/HDL cholesterol (less than 6.9) throughout the trial or who initially had higher values (greater than 6.9) that were significantly lowered by dietary intervention.