Cardiovascular Disease

Excerpt

The cardiovascular diseases (CVDs) considered in this chapter have been the major cause of morbidity and mortality in developed countries over the last several decades, and developing countries are rapidly catching up with this epidemic. The underlying pathology is atheromatous vascular disease, resulting in coronary artery disease (CAD), cerebrovascular disease, and peripheral vascular disease, and the subsequent development of heart failure and cardiac arrhythmias. The major risk factors for these disorders were recognized over many years, and they include high levels of low-density lipoprotein (LDL) cholesterol, smoking, hypertension, diabetes, abdominal obesity, psychosocial factors, insufficient consumption of fruits and vegetables, excess consumption of alcohol, and lack of regular physical activity. There has been continued research to help define more precisely the cardiovascular risk of an individual with respect to genetic factors, more complex lipid traits, and inflammatory markers, but it was reconfirmed in the INTERHEART study that the conventional risk factors accounted for over 90% of the population attributable risk for myocardial infarction (MI; Yusuf et al. 2004). There is extensive evidence to show that drug treatment of conventional risk factors is effective in reducing cardiovascular events. Many large clinical trials with the HMG CoA reductase inhibitors (statins) have showed that lowering of LDL cholesterol with these agents decreases coronary and cerebrovascular events (Baigent et al. 2005), and that the target for LDL cholesterol becomes lower with each new set of guidelines and the availability of more potent drugs (Anderson et al. 2007). Likewise, more effective treatment of hypertension with various classes of antihypertensive drugs has been associated with greater benefits (Turnbull et al. 2008), but some recent studies suggest we may be reaching the optimal level of treated blood pressure in some patient groups (ACCORD Study Group 2010). Apart from the treatment of cardiovascular risk factors with pharmacological agents and the use of antithrombotic drugs, there is growing awareness of the role of dietary factors and herbal medicines in the prevention of CVD and the possibility of their use in treatment. Much of this interest centers on the use of antioxidant vitamins and the antioxidant properties of herbal materials, although some herbal materials may also improve conventional cardiovascular risk factors or have antithrombotic effects. In this chapter, we focus mainly on the results from large clinical trials and meta-analyses rather than from mechanistic studies, and we start by considering the use of antioxidant vitamins and other essential micronutrients in Section 16.2 before moving to a discussion of individual herbs in Section 16.3.