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

Spontaneous regression of coronary artery obstructions: incidence in 313 consecutive repeat angiograms

We studied the incidence of reversibility of coronary obstructions in a consecutive series of 313 patients with nonoperated coronary artery disease catheterized twice 3 to 118 (mean 38) months apart. Recanalization was observed in three patients and regression from an initial less than 100% obstruction in six patients. Progression in a different location occurred in six of the nine patients who demonstrated one recanalized or one regressive lesion. We conclude that true regression is an infrequent event in the natural history of medically treated patients with coronary artery disease; moreover, the pathophysiology and clinical relevance of angiographic regression remain poorly defined.

Prevention of progression of coronary atherosclerosis by treatment of hyperlipidaemia: a seven year prospective angiographic study

The progression of coronary atherosclerosis was assessed by repeat angiography in 28 patients and 20 controls with hyperlipidaemia (serum cholesterol concentration greater than 7.2 mmol/l (278 mg/100 ml) or serum triglyceride concentration greater than 2.0 mmol/l (177 mg/100 ml), or both) and symptomatic coronary artery disease of two or three vessels. Twenty eight patients (26 men and two women) were treated with diet and drugs (clofibrate or nicotinic acid, or both) to lower lipid concentrations. Twenty men taking part in a simultaneous study served as non-randomised controls. They received medical treatment for coronary artery disease but no treatment to reduce lipid concentrations. The initial levels of coronary risk factors and the angiographic state were comparable in the two groups. In the 28 patients total cholesterol, total triglyceride, and low density lipoprotein cholesterol concentrations were reduced by an average 18%, 38%, and 19% respectively by treatment for hyperlipidaemia and high density lipoprotein cholesterol concentration was increased on average by 10%. The treatment maintained these concentrations during a follow up of seven years. By all criteria coronary lesions progressed significantly less in the patients than the controls: the angiographic state remained completely unchanged in nine (32%) of the patients compared with only one (8%) of the surviving controls; of the arterial segments at risk, 46 (16.5%) progressed in the patients compared with 50 (38.2%) in the controls (p less than 0.001); and the coronary obstruction increased less in patients than in controls (p less than 0.05). Cardiac survival was 89% in seven years in the patients compared with 65% in five years in the controls (p less than 0.01). The anginal symptoms diminished or remained stable in 16 of the 24 patients who survived until the end of the study. The progression of coronary atheromatosis was significantly greater in those patients who during the seven years of treatment had an average total cholesterol concentration, VLDL plus LDL cholesterol concentration, or ratio of LDL to HDL cholesterol concentration above the respective median value than in those with the corresponding values below median. On the other hand, the patients with HDL cholesterol concentrations above the median during treatment showed less progression than those with lower HDL cholesterol concentrations. The increase in coronary obstruction was inversely related to the average HDL cholesterol concentration during treatment. The progression was not, however, related to LDL cholesterol concentration during treatment.(ABSTRACT TRUNCATED AT 400 WORDS)

How much of the placebo 'effect' is really statistical regression?

Statistical regression to the mean predicts that patients selected for abnormalcy will, on the average, tend to improve. We argue that most improvements attributed to the placebo effect are actually instances of statistical regression. First, whereas older clinical trials susceptible to regression resulted in a marked improvement in placebo-treated patients, in a modern series of clinical trials whose design tended to protect against regression, we found no significant improvement (median change 0.3 per cent, p greater than 0.05) in placebo-treated patients. Secondly, regression can yield sizeable improvements, even among biochemical tests. Among a series of 15 biochemical tests, theoretical estimates of the improvement due to regression by selection of patients as high abnormals (i.e. 3 standard deviations above the mean) ranged from 2.5 per cent for serum sodium to 26 per cent for serum lactate dehydrogenase (median 10 per cent); empirical estimates ranged from 3.8 per cent for serum chloride to 37.3 per cent for serum phosphorus (median 9.5 per cent). Thus, we urge caution in interpreting patient improvements as causal effects of our actions and should avoid the conceit of assuming that our personal presence has strong healing powers.

Influence of clofibrate, bile-sequestering agents and probucol on high-density lipoprotein levels

The management of lipid disorders has been greatly improved by advances in our understanding of lipoprotein metabolism. New developments in the isolation and quantitation of the lipoprotein apoproteins have shed light on their essential role in normal and abnormal lipid transport and have helped clarify the mode of action of lipid-lowering drugs. Excess lipid levels can occur because of overproduction, faulty degradation or defective removal of 1 or more lipoproteins. Clofibrate appears to decrease levels of very low density lipoproteins (VLDL) and intermediate-density lipoproteins (IDL) by enhancing their intravascular degradation. Although it often slightly decreases low-density lipoprotein (LDL) levels, it may markedly increase LDL levels in patients with initially high VLDL levels. Its effects on high-density lipoproteins (HDL) are small, often increasing HDL slightly. Bile acid sequestrants act by enhancing the rate of removal of LDL. Their effects on VLDL and IDL are slight. In some subjects there is a moderate increase in both VLDL and IDL levels. HDL concentrations are increased minimally. Probucol's mechanism of action is still unclear, but it appears to enhance LDL removal. Its effects on VLDL and IDL are minimal. Of concern is the repeated observation that probucol reduces HDL concentrations by decreasing HDL synthesis. The resultant reduction in HDL concentrations often rivals its effect in decreasing LDL levels. Knowledge of the selective effect of lipid-lowering drugs on specific lipoprotein fractions is essential for their proper therapeutic selection.

The effects of colestipol hydrochloride on serum lipoprotein lipid and apolipoprotein B and A-I concentrations in children heterozygous for familial hypercholesterolemia

The effects of colestipol hydrochloride on serum lipoprotein lipid and apolipoprotein B and A-I concentrations in children heterozygous for familial hypercholesterolemia. Acta Paediatr Scand, 72:81, 1983.--Colestipol hydrochloride was administered to 28 children with familial hypercholesterolemia type II-A, and its effects on serum lipoproteins were tested against a placebo in a cross-over design. All children consumed a diet low in cholesterol and high in linoleic acid. Colestipol therapy resulted in a 15.7% decrease in serum very low plus low density lipoproteins and in a 13.5% decrease in serum apolipoprotein B. High density lipoprotein cholesterol, serum apolipoprotein A-I and serum triglycerides remained unaltered.

Reliability of assessing change with sequential coronary angiography

Data are presented from a study evaluating the reliability of sequential angiography in estimating changes in coronary lesions. Three panels of three expert angiographers each read on two separate, independent occasions 18 sets of paired angiograms taken 24 months apart. All readers were blinded to the temporal sequence of the films, clinical data, and ventriculography information. The need for simultaneous viewing and reading of the two films, for training sessions, and for allowance to be made for apparent differences arising from boundary definitions prior to final analysis was demonstrated. Under stringent conditions (determination of change based on agreement of at least two out of three panels of physicians) it was possible to ascertain change in coronary atherosclerosis from sequential sets of coronary angiograms with good reliability. However, single-panel readings yielded an unacceptable overestimate of the number of patients with lesion changes.

Coronary disease progression and its effect on left ventricular function

To determine the effect of coronary disease progression on left ventricular function, 47 patients who had two cardiac catheterizations at a mean interval of 25 months (range three to 92 months) without intervening surgery were studied. Of these, 35 patients had coronary disease and 12 patients had normal or near normal coronary arteries. Coronary disease progression was seen more often in patients with initial coronary disease than in those without significant disease (66 percent vs 25 percent, p less than 0.02). Left ventricular ejection fraction decreased in patients with coronary disease progression (0.63 +/- 0.03 to 0.51 +/- 0.04, p less than 0.01) but was unchanged in patients without progressive disease (0.58 +/- 0.04 to 0.57 +/- 0.93, p = NS). Interval myocardial infarction was the major cause of deteriorating left ventricular function. The rate or degree of coronary disease progression did not predictably change global left ventricular function, and progressive disease in individual vessels did not predictably alter regional left ventricular function. The presence or development of collateral vessels did not significantly alter ventricular performance.

Hyperlipidemia therapy: can it prevent coronary atherosclerosis?

Improvements in diagnosis permit primary care physicians to identify lipid disorders. Until recently, most of the therapy for coronary artery disease was directed at the symptoms produced by the ischemic myocardium. As more studies reveal the close relationship between the presence of abnormal lipid levels and the prevalence and progression of coronary artery disease, physicians who care for coronary patients should pay closer attention to the possibility of preventing or attenuating progression of the disease. The development of effective drugs represents an initial phase in long-range resolution of the problem of progressive vascular disease. While dietary management is important, pragmatic considerations suggest that modification of serum lipids to ideal levels will require the use of polypharmacy.

Protection of myocardium by the compensatory mechanism of coronary collaterals after total occlusion of major coronary arteries shown in patients with familial hypercholesterolemia

We report 11 in a group of 21 asymptomatic patients with heterozygous familial hypercholesterolemia (FH) and progressive coronary artery disease to evaluate the role of compensatory mechanism(s), especially coronary collaterals, in providing adequate blood supply to the myocardium, following complete occlusion of one or more major coronary arteries. Diet-colestipol-nicotinic acid treatment decreased their plasma total cholesterol and low density lipoprotein cholesterol (mg/dl, mean +/- SEM) from 442.9 +/- 25.8 and 363.0 +/-24.1, respectively, to 231.2 +/- 11.8 and 185.3 +/- 14.2, respectively, for 6 to 9 years. The initially stenotic lesions of these 11 patients slowly progressed to complete occlusion, while the patients remained free of myocardial ischemia or infarction and exhibited no abnormality on 24-hour ambulatory ECG monitoring, exercise stress, and thallium 201 stress tests. We conclude that coronary occlusion can be retarded in FH patients by strenuous hypocholesterolemic therapy to allow the development of compensatory mechanism including coronary collaterals. Apparently, the angiographically visualizable collaterals combined with subendocardial anastomosis can give adequate myocardial blood supply to this series of FH patients following occlusion of one or more of their major coronary arteries.

Diverging effects of cholestyramine on apolipoprotein B and lipoprotein Lp(a). A dose-response study of the effects of cholestyramine in hypercholesterolaemia

Nineteen hypercholesterolaemic patients were randomly treated with either 16 or 8 g cholestyramine with a changeover after 6 weeks for a second 6-week period. During a third consecutive 6-week period all patients received 4 g cholestyramine daily. The low density lipoprotein (LDL) cholesterol and triglyceride concentrations decreased significantly (- 11%, - 21% and - 26% for LDL cholesterol on 4, 8 and 16 g, respectively) with a dose-response effect. However, the increase from 8 g to 16 g only caused a modest additional reduction of the lipid levels. The serum concentration of apolipoprotein (apo) B was correlated to the LDL cholesterol and decreased similarly in a dose-response fashion. However, the average reduction of apo B was less pronounced (- 4%, - 13% and - 17% on 4, 8 and 16 g of cholestyramine, respectively) resulting in a significant change of the apo B/LDL cholesterol ratio during treatment. There was a significant increase of the high density lipoprotein (HDL) cholesterol concentration, which was similar at all dose levels. Also, the apo A-I concentration in serum increased significantly but the relative decrease was less pronounced than that of HDL cholesterol, causing a significant decrease of the apo A-I/HDL cholesterol ratio. The apo A-II concentration in serum was unchanged or slightly decreased and the apo A-I/apo A-II ratio increased significantly.

Regulation of high density lipoprotein levels

Current concepts of the structure and metabolism of high density lipoproteins are presented and factors that influence their levels in human beings are surveyed.

Effect of lipid-lowering therapy on the progression of coronary atherosclerosis assessed by scheduled repetitive coronary arteriography

We studied 42 subjects, each of whom demonstrated significant (greater than or equal to 50%) narrowing of a non-grafted coronary artery and a baseline cholesterol level greater than 250 mg%. All patients underwent repeat scheduled coronary arteriography after 2 years on the study. Twenty-five colestipol responders (cholesterol levels reduced at least 15% within 1 month of therapy) were compared to 17 non-responders who were given 23 months of placebo after a 1 month exposure to colestipol. Baseline risk factors and demographic characteristics were similar for the two groups. In comparison to baseline arteriography, only 3 of the 25 drug-treated patients showed progression, while 8 of 17 placebo treated patients demonstrated progression (P = 0.011). Drug-treated patients demonstrated a 20% decrease in cholesterol levels, while placebo patients did not experience a significant reduction in cholesterol levels. Our study suggests that significant reduction in serum cholesterol levels is associated with a reduced likelihood of progression of coronary atherosclerotic lesions assessed by scheduled repetitive coronary arteriography in hyperlipidemic subjects demonstrating significant coronary artery narrowing on their initial arteriograms.

"Low dose" colestipol in children, adolescents and young adults with familial hypercholesterolemia

The effect of colestipol on plasma lipids and lipoproteins was studied in children, adolescents and young adults with familial hypercholesterolemia. O.125 g or 0.25 g/kg body weight were given in randomized sequence for period of 4 weeks. Total cholesterol was lowered by 13 and 18% with the smaller and larger dose , respectively, and LDL cholesterol lowered by 15% with the smaller and 12% with the larger dose. HDL cholesterol rose by 18 an 32%. LDL composition before and during the study was abnormal due to a markedly reduced triglyceride content. "Low-dose" colestipol is less effective lowering total plasma and LDL cholesterol than conventional doses but may, due to very few side effects, by advantageously used in cases of familial hypercholesterolemia when plasma cholesterol levels after dietary management are only 15-20% above normal.

Lipid peroxide levels and lipids content of serum lipoprotein fractions of pregnant subjects with or without pre-eclampsia

Total serum lipids in normal pregnant subjects were significantly higher than those in non-pregnant subjects. This was due to an increase in the lipid content in all of the lipoprotein fractions, especially in VLDL. Serum lipids in pre-eclamptic subjects were higher than those in normal pregnant subjects. This was due to the increase in both VLDL and LDL. Serum lipid peroxide levels in pregnant subjects were significantly higher than those in non-pregnant subjects and further elevation of the levels was observed in pre-eclamptic subjects. The elevation of the peroxide levels in normal pregnant subjects was due to changes in all of the fractions of serum lipoproteins, especially in VLDL. The further elevation of peroxide in pre-eclamptic subjects resulted from an increase in HDL fraction.

Comparison of the effects of colestipol hydrochloride and clofibrate on plasma lipids and lipoproteins in the treatment of hypercholesterolemia

The effects of colestipol HCl resin and clofibrate on plasma lipid and lipoprotein levels were compared in 65 patients with primary hypercholesterolemia. Patients were randomly assigned to treatment with colestipol (in progressive doses of 15, 20, and 30 g/day), clofibrate (2 g/day), or placebo resin; lipoprotein levels were determined at months 0, 2, 4, 6, and 9. The colestipol group received both colestipol and clofibrate during months 7 through 9 of the study. After 6 months of treatment, mean plasma total cholesterol fell from 333 to 266 (P less than 0.01) on colestipol, and from 329 to 270 (P less than 0.05) on clofibrate. More patients responded, however, to colestipol than to clofibrate. Both drugs also produced significant reductions in LDL cholesterol levels, and clofibrate lowered plasma triglycerides as well. HDL cholesterol level did not change significantly on either medication. The placebo group showed no change in any of the parameters studied. A significant difference was not observed between the effects of 15 g/day of colestipol and those of the higher doses studies. Addition of clofibrate to colestipol did not enhance the latter's hypocholesterolemic action.

Familial type II hyperlipoproteinemia with coronary heart disease: effect of diet-colestipol-nicotinic acid treatment

Heterozygous familial type II hyperlipoproteinemia (F type II) is primarily manifested in hypercholesterolemia (due to low density lipoprotein-cholesterol [LDL-C] elevation) and premature coronary heart disease (CHD). We studied sequentially the effects of low cholesterol-low saturated fat-low simple carbohydrate diet; diet and colestipol, 30 g/day; and diet, colestipol, plus nicotinic acid (NA) 3 to 7 g/day on plasma cholesterol (Ch), LDL-C, triglyceride (TG), high density lipoprotein-cholesterol (HDL-C) and angiographically documented coronary arterial lesions of 32 F type II patients. Effective control of F type II resulted in arresting the progression of angiographically demonstrated coronary arterial lesions.

Synergistic effects of probucol and cholestyramine to lower serum cholesterol

Ten men with hypercholesterolemia were treated sequentially with a fat-modified diet, a diet plus probucol (1 Gm/day), and a diet plus probucol plus cholestyramine (16 Gm/day). Each treatment period was 12 weeks. Diet alone reduced mean serum cholesterol by 1.0 per cent. Diet plus probucol caused a mean 7.7 per cent reduction in serum cholesterol below the baseline values (P = 0.001 compared to diet). Adding cholestyramine to probucol and diet resulted in a mean 18.2 per cent reduction in serum cholesterol below baseline values (P = 0.001 compared to probucol and diet). The treatment was well tolerated.

[The National Research Program 1A: a community-oriented intervention study. Methodological considerations on various types of studies]

Intervention tricals can principally be classified into community or clinically oriented designs. The clinical approach of the randomized controlled trial (RCT) implies the individual randomization of a volunteer population into a study and a control group. In community-oriented trials, however, the study and control group are not composed of individuals, but rather of total population groups (e.g. communities, factories). The paper gives first an overview over the historial development of epidemiological methods as the basis for both study types. Shortcomings and advantages both of RCT's and of community trials are discussed, using the examples of the "diet-heart" hypothesis and of the National Research Program 1A design, respectively. The two study types uses as primary endpoints for the analysis changes in risk factor distribution, morbidity and/or mortality. A recent alternative is presented, too: advances in angiography allow direct measurements of changes in vessels with atherosclerotic disease. The different study types available complement one another in trying to understand the mechanisms involved in disease of multifactorial origin.

Assessment of long-term plasma exchange for familial hypercholesterolaemia

The effectiveness of repeated plasma exchange with 2 to 4 litres of plasma protein fraction as long-term treatment for familial hypercholesterolaemia has been evaluated in six severely affected patients receiving conventional cholesterol lowering treatment. Cell-separator mediated exchange at monthly intervals for one to two years reduced mean serum cholesterol levels from 18.5 mmol/l (715 mg/dl) to 12.4 mmol/l (480 mg/dl) in two female homozygotes but failed to influence xanthomata or prevent a two- to threefold increase in their left ventricular aortic systolic pressure gradients. More effective reduction of mean serum cholesterol levels from 15.7 mmol/l (608 mg/dl) to 8.6 mmol/l (333 mg/dl) in two male homozygotes by plasma exchange at fortnightly intervals for two to three years was accompanied by resolution of xanthomata and by stabilisation of aortocoronary lesions. In two male heterozygotes with angina, coronary angiographic appearances were unaltered or improved after one to two years of thrice-monthly plasma exchange, which reduced mean serum cholesterol levels from 6.4 mmol/l (248 mg/dl) to 4.7 mmol/l (182 mg/dl). We conclude that plasma exchange every one to two weeks, combined with oral nicotinic acid and/or cholestyramine, retards the rate of progression of atheroma in homozygotes and possibly induces regression in heterozygotes.

Colestipol: a review of its pharmacological properties and therapeutic efficacy in patients with hypercholesterolaemia

Colestipol is an anion exchange resin with bile acid sequestering properties resembling those of cholestyramine, another lipid-lowering binding resin. In daily doses of 15 to 30g colestipol reduces total plasma cholesterol concentrations (primarily low density lipoprotein cholesterol) by about 15 to 30%, but plasma triglyceride concentrations may be unchanged or in some patients increased. Thus, like cholestyramine, colestipol is of benefit in patients with primary hypercholesterolaemia without associated hypertriglyceridaemia (type IIa hyperlipoproteinaemia). Colestipol is odourless and tasteless, and is said by some to be more readily tolerated by patients than cholestyramine, leading to improved compliance, but such data has not been documented in most studies. Side effects of colestipol treatment are primarily gastrointestinal in nature since the drug is essentially unabsorbed. As with cholestyramine, colestipol may bind with other concomitantly administered drugs reducing their absorption or enterohepatic recirculation; dosage intervals of other concurrent medications should be adjusted to minimise the potential for such an interaction.

Spontaneous return of patency in a completely occluded coronary artery

We observed a 56-year=old man in whom an occluded right coronary artery was observed to be widely patent on a subsequent angiogram 40 months later. This "regression," which occurred without a change in his risk factors, shows that manipulation of risk factors can be proven to be a cause of regression only in controlled studies.