Continuous flow plasma exchange in the treatment of homozygous familial hypercholesterolemia.

We report the clinical and laboratory effects of continuous-flow plasma exchange in two patients suffering from homozygous familial hypercholesterolemia. In one (Case 1) plasmapheresis was performed at fortnightly intervals over a period of 18 months; in the other (Case 2) the necessity for surgical relief of an associated supravalvular aortic stenosis resulted in premature termination of the trial. The plasma cholesterol levels in both patients fell by 35 per cent from the mean before study in the course of treatment. In Case 1 this was associated with marked regression of the patient's xanthomas, disappearance of the S-T segment depression seen on effort electrocardiograms obtained prior to the introduction of plasmapheresis, possible widening of the stenosis present at the origin of the left anterior descending coronary artery, and a marked increase in exercise tolerance and diminished frequency of anginal attacks. Cessation of cholestyramine and clofibrate administration during this study did not in any way reverse the reduction of plasma cholesterol achieved by means of plasmapheresis combined with drug therapy. We conclude that plasmapheresis has a role to play in the management of patients with homozygous familial hypercholesterolemia.