Defining the role of lipoprotein apheresis in the management of familial hypercholesterolemia

Abstract

Familial hypercholesterolemia (FH) is an autosomal co-dominant disorder characterized by a marked elevation of serum low-density lipoprotein (LDL) cholesterol (LDL-C) concentration, which in turn is associated with a greatly increased risk of premature cardiovascular disease. International consensus recommends the use of statins as the first line of treatment for patients with this condition. However, homozygote FH patients with persistently elevated LDL-C levels are usually resistant to multiple-drug therapy. Fortunately, LDL apheresis (or simply 'lipoprotein apheresis') provides a treatment option for patients who are refractory or intolerant to lipid-lowering medications, or if there is progressive cardiovascular disease despite maximal drug therapy. Lipoprotein apheresis is an extracorporeal LDL-C-lowering treatment similar in concept to renal dialysis. There are now five main methods for extracorporeal lipoprotein apheresis in use, namely dextran sulfate adsorption (DSA), heparin extracorporeal LDL precipitation (HELP), polyacrylate full blood adsorption (PFBA or DALI® system) using hemoperfusion, immunoadsorption, and filtration plasmapheresis. Lipoprotein apheresis has been shown to be successful in reducing LDL-C levels, as well as levels of lipoprotein(a) [Lp(a)], a prothrombotic proatherogenic lipoprotein. In contrast, however, lipoprotein apheresis seems to have a smaller effect in preventing atherosclerosis progression, thus suggesting that a major component of the reduction in cardiovascular events may be mediated by mitigating Lp(a) levels. Side effects are infrequent and mild, and have mainly consisted of lightheadedness, nausea, vomiting, and hypotension. As these are often bradykinin-mediated and associated with concomitant ACE inhibitor use, angiotensin type 2 receptor antagonists should be used instead of ACE inhibitors with DALI and PFBA. Nevertheless, there is scope for wider application of lipoprotein apheresis. The high cost and invasive nature of lipoprotein apheresis limits uptake; however, it is an important treatment modality that should be considered in carefully selected patients. National and international registries compiling outcome data for lipoprotein apheresis need to be established to help expand the evidence base regarding its effectiveness.