Can aggressive lipid lowering using low-density lipoprotein apheresis prevent restenosis after percutaneous transluminal coronary angioplasty in patients with normocholesterolemia?

Differences in the atherogenic risk of patients treated by lipoprotein apheresis according to their lipid pattern

In high-risk patients who are already on a maximal lipid-lowering therapy, a lipoprotein apheresis is an important therapeutic option in preventing further progress of vascular complications as it may decrease both LDL-cholesterol (LDL-C) and lipoprotein(a) (Lp(a)) levels. We looked at the occurrence of cardiovascular events before apheresis and during apheresis in three groups defined by their lipid patterns at the start of an apheresis treatment: Group 1 (LDL-C ≥ 3.4 mmol/l and Lp(a) ≤ 600 mg/l; n = 35), Group 2 (LDL-C ≤ 3.4 mmol/l and Lp(a) ≥ 600 mg/l n = 37) and Group 3 (LDL-C ≥ 3.4 mmol/l and Lp(a) ≥ 600 mg/l; n = 15). Group 2 shows a time period of about 10 years from the first event until the start of apheresis treatment (compared to 2-6 years in the other two groups). Before the start of apheresis treatment 2.1 events per patient had occurred in Group 1, 3.4 events per patient in Group 2 and 1.8 events per patient in Group 3. Under apheresis therapy just 0.9 events per patient occurred in Group 1, 0.5 in Group 2 and 0.5 in Group 3. When comparing the two years before the start of apheresis treatment with the first two years under apheresis we saw the following reduction rates of cardiovascular events: Group 1-54%; Group 2-83%; Group 3-83.5%. Our results show that the reduction of cardiovascular events due to lipoprotein apheresis is especially high in patients with elevated levels of Lp(a) compared to patients with elevated LDL-C only indicating that physicians should be more focused on the risk factor elevated Lp(a).

Influence of serum cholesterol on atherogenesis and intimal hyperplasia after angioplasty: inhibition by amlodipine

The objectives of the present study were to determine whether serum hypercholesterolemia (HC) promotes the development of spontaneous and angioplasty-induced lesions and whether amlodipine inhibits these lesions and cellular processes underlying their genesis. Rabbits were fed normal, 0.5%, or 2% cholesterol diets for 9 wk, which resulted in the development of increasing HC. After week one, balloon dilation of the abdominal aorta was performed while the thoracic aorta was not disturbed and monitored for the development of spontaneous lesions. Lesion size increased with the degree of HC and was accompanied by increased collagen synthesis and smooth muscle cell (SMC) proliferation at each site. Amlodipine (5 mg/kg p.o.) inhibited lesion size by 50% (P < 0.01) at both sites in cholesterol-fed animals but not at angioplasty sites in animals on a normal diet. Local collagen synthesis was inhibited at both sites by amlodipine in the diet animals. The increase in HC was accompanied by a 1.7-fold increase in basal Ca2+ uptake in SMCs in the thoracic aorta, which was not altered by amlodipine, nifedipine, Ni2+, or La3+, revealing an uninhibitable calcium leak during atherogenesis. In culture, cholesterol enrichment increased SMC proliferation, collagen synthesis, and the secretion of a soluble SMC mitogen, which were inhibited by amlodipine (10(-9) M). Finally, in SMC membranes, amlodipine uniquely restored the cholesterol-expanded membrane bilayer width without any effect on membrane fluidity. This study establishes a causal role between serum HC and the development of spontaneous and angioplasty-induced lesions and the ability of amlodipine to disrupt this action by a novel remodelling action on the SMC membrane.

LDL apheresis

Low density lipoprotein (LDL) apheresis provides a safe and effective means of treating patients with homozygous familial hypercholesterolaemia (FH). It also has a role in preventing the progression of coronary artery disease in heterozygotes and others with severe dyslipidaemia who are refractory to or intolerant of high doses of lipid-lowering drugs. Established methods involve either adsorption of apolipoprotein B-containing lipoproteins by affinity columns containing anti-apolipoprotein B antibodies or dextran sulphate, or their precipitation at low pH by heparin, in each instance after first separating plasma from blood cells with a cell separator. The most recently developed method enables lipoproteins to be adsorbed directly from whole blood, using polyacrylate columns. All 4 methods have proved to be similarly efficient when used weekly or biweekly to lower LDL cholesterol and Lp(a) without unduly reducing HDL cholesterol. Economic constraints restrict the use of LDL apheresis to the treatment of potentially fatal disorders such as FH, where there is clear evidence of benefit compared with conventional therapy. Widening the indications to include the treatment of other dyslipidaemic disorders such as steroid-resistant nephrotic syndrome, post-transplant donor vessel disease, stroke and prevention of re-stenosis after coronary angioplasty requires evidence from controlled trials that is currently lacking.