The impact of lipoprotein apheresis in patients with refractory angina and raised lipoprotein(a): Objectives and methods of a randomised controlled trial

Abstract

It is well established that Lipoprotein(a) [Lp(a)] is an independent cardiovascular risk factor and predictor of major adverse cardiovascular events. Lipoprotein apheresis is currently the most effective approved treatment available, with minimal effect conferred by conventional lipid lowering agents. A growing body of evidence suggests that aggressively lowering raised Lp(a) may improve cardiovascular and clinical outcomes, although more prospective research is required in this field.Angina which is refractory to conventional medical therapy and revascularisation is extremely challenging to manage. There is a significant unmet need to establish therapeutic options.Our goal is to determine the impact of lipoprotein apheresis on clinical parameters and symptoms of patients with refractory angina secondary to advanced coronary disease and raised Lp(a). Determining whether we should aggressively lower Lp(a) in such patients remains a very important question, which could potentially impact on the management of a large population. We will also gain insight into how this treatment works and the mechanisms via which Lp(a) increases cardiovascular risk.We are currently conducting a prospective, randomised controlled crossover study of patients with refractory angina and raised Lp(a), randomised to undergoing three months of weekly lipoprotein apheresis or sham apheresis. Patients will then crossover to the opposite study arm after a 1 month wash-out phase. We will assess myocardial perfusion, carotid atherosclerosis, endothelial vascular function, thrombogenesis, oxidised LDL and their antibodies, exercise capacity, angina and quality of life at the beginning and end of treatment, to determine the net true treatment effect on the above parameters. This is a novel area of research, as previous studies have not assessed the role of lipoprotein apheresis in patients with refractory angina and raised Lp(a) in a prospective randomised controlled manner.