The expanding role of lipoprotein apheresis in the treatment of raised lipoprotein(a) in ischaemic heart disease and refractory angina

It is increasingly recognised that lipoprotein(a) [Lp(a)], an inherited, genetically-determined form of LDL-cholesterol, is an independent cardiovascular risk factor and predictor of adverse cardiovascular outcomes. Lp(a) is felt to increase cardiovascular risk via its pro-thrombotic effect and by enhancing intimal lipoprotein deposition. Lipoprotein apheresis is currently the most effective treatment for raised Lp(a). There is a growing body of evidence suggesting that aggressively lowering raised Lp(a) may improve cardiovascular and clinical outcomes, although much more research is required in this field.

Angina which is refractory to conventional medical therapy and revascularisation, is extremely challenging to manage. Treatment options for such patients remain very limited. We describe the case of a patient with refractory angina and raised lipoprotein(a) in whom aggressive reduction of Lp(a) with lipoprotein apheresis successfully ameliorated the progression of coronary stenosis and provided effective and durable relief of angina symptoms. In our centre, we are currently conducting a prospective, randomised controlled cross-over study of patients with refractory angina and raised Lp(a), randomised to undergoing lipoprotein apheresis or ‘sham’ apheresis with assessment of myocardial perfusion, carotid atherosclerosis, endothelial vascular function, thrombogenesis, oxidised phospholipids and their antibodies, exercise capacity, angina symptoms and quality of life at the beginning and end of treatment.

Obesity-related non-communicable diseases: South Asians vs White Caucasians

South Asians are at higher risk than White Caucasians for the development of obesity and obesity-related non-communicable diseases (OR-NCDs), including insulin resistance, the metabolic syndrome, type 2 diabetes mellitus (T2DM) and coronary heart disease (CHD). Rapid nutrition and lifestyle transitions have contributed to acceleration of OR-NCDs in South Asians. Differences in determinants and associated factors for OR-NCDs between South Asians and White Caucasians include body phenotype (high body fat, high truncal, subcutaneous and intra-abdominal fat, and low muscle mass), biochemical parameters (hyperinsulinemia, hyperglycemia, dyslipidemia, hyperleptinemia, low levels of adiponectin and high levels of C-reactive protein), procoagulant state and endothelial dysfunction. Higher prevalence, earlier onset and increased complications of T2DM and CHD are often seen at lower levels of body mass index (BMI) and waist circumference (WC) in South Asians than White Caucasians. In view of these data, lower cut-offs for obesity and abdominal obesity have been advocated for Asian Indians (BMI; overweight >23 to 24.9 kg m(-2) and obesity ≥ 25 kg m(-2); and WC; men ≥ 90 cm and women ≥ 80 cm, respectively). Imbalanced nutrition, physical inactivity, perinatal adverse events and genetic differences are also important contributory factors. Other differences between South Asians and White Caucasians include lower disease awareness and health-seeking behavior, delayed diagnosis due to atypical presentation and language barriers, and religious and sociocultural factors. All these factors result in poorer prevention, less aggressive therapy, poorer response to medical and surgical interventions, and higher morbidity and mortality in the former. Finally, differences in response to pharmacological agents may exist between South Asians and White Caucasians, although these have been inadequately studied. In view of these data, prevention and management strategies should be more aggressive for South Asians for more positive health outcomes. Finally, lower cut-offs of obesity and abdominal obesity for South Asians are expected to help physicians in better and more effective prevention of OR-NCDs.

Dyslipidemia in South Asian patients

South Asians around the globe have the highest rates of coronary artery disease (CAD). These rates are 50% to 300% higher than other populations, with a higher risk at younger ages. These high rates of CAD are accompanied by low or similar rates of major traditional risk factors. The prevalence of diabetes is three to six times higher among South Asians than Europeans, Americans, and other Asians but does not explain the "South Asian Paradox." A genetic predisposition to CAD, mediated by high levels of lipoprotein(a), markedly magnifies the adverse effects of traditional risk factors related to lifestyle and best explains the South Asian Paradox. Although the major modifiable risk factors do not fully explain the excess burden of CAD, they are doubly important and remain the foundation of preventive and therapeutic strategies in this population. A more aggressive approach to preventive therapy, especially dyslipidemia, at an earlier age and at a lower threshold is clearly warranted.