HEART disease affecting the arteries of the heart is known to be the result of several processes that occur over decades and result in the accumulation of cholesterol in the walls of the arteries of the heart.

Research studies performed over several decades have identified many of the processes that promote the deposition of cholesterol (atherosclerosis). These include hypertension, diabetes, abnormalities of blood cholesterol, smoking, family history, etc. Over the past several decades, inflammation has been identified as an important factor in the development of many disease processes including disease of the heart arteries (coronary artery disease). Inflammation not only has a role as a risk factor for the development of heart disease, but it also plays a direct role in the process of accumulation of cholesterol in the heart arteries and chronic inflammation may be a determinant factor in the severity and outcome of heart disease.

What is inflammation?

Inflammation is a normal process that takes place in our bodies. Most typically we experience inflammation in response to injury. We have all had the experience of injuring our skin with a cut or a blunt injury. The area that is injured becomes warm, swollen and red. These changes are because of vascular and local chemical processes that act to resolve the injury. Chemicals are released that dilate blood vessels, attract white blood cells, increase the permeability of blood vessels, and increase clotting. These actions together lead to the destruction of dead tissue, prevention or containing of infection and the restoration of the injured area often with scar tissue. In scenarios in which a large area of injury occurs such as with a widespread bacterial infection, the inflammatory process affects the entire body. Hormones and chemical agents are released into the blood stream which have several actions. They can have positive effects of activating the immune system to aggressively counter the infection, increase the cardiac output to deliver oxygen, improving the ability of the blood to clot and to break down inappropriate clot. Symptoms of severe infection such as fever, malaise and loss of appetite are often related to the effects of inflammation.

Inflammation in response to an injury or infection is usually a temporary phenomenon that subsides once the injury or infection has healed. Inflammation can, however, be chronic and most often this is a result of disease or factors which stimulate the inflammatory process inappropriately. This inappropriate stimulation of the inflammatory process can result in damage to healthy tissue and the development of a variety of disease conditions. Several disease states are well known to result in inflammation in the body. Rheumatoid arthritis results in the production of chemical agents which act to damage various tissues including blood vessels. Other immune diseases such as systemic lupus and psoriasis have been also documented to result in inflammation and damage to blood vessels. Obesity, smoking, HIV, poor diet, COVID infection, genetics, lack of exercise, infections, blood cholesterol abnormalities have been demonstrated to cause chronic inflammation which can affect the heart and its blood vessels.

How does inflammation affect the blood vessels of the heart?

Obstruction of the blood vessels supplying the heart is often described as cholesterol “getting laid down in the vessel wall” but what is often not made clear is the role that the inflammatory process plays. Pathologic studies have clearly demonstrated that integral role of inflammation across the entire spectrum of coronary artery disease including the initial development of cholesterol plaque, the continuing accumulation of cholesterol in the wall of the artery, the conversion of soft cholesterol to fibrous tissue and calcium and the rupture of cholesterol plaque leading to heart attack. Increasingly inflammation is being noted as part of the pathologic process of other cardiac diseases including heart failure and valvular heart disease.

Clinical effects of inflammation in heart disease

For several decades the role of chronic inflammation in cardiac disease has been become more evident. In the 1990s a clinical marker of inflammation, the high sensitivity C-reactive protein (hs-CRP), was shown to be a marker for cardiac risk. Clinical studies found that treatment with lipid lowering drugs could improve the prognosis of patients with high hs-CRP levels even if they already had normal blood cholesterol levels. What has also become clear is that patients with chronic inflammation from other diseases have elevated risk of developing coronary artery disease. Patients with rheumatoid arthritis, for example, have a risk of developing coronary artery disease that is the same as a patient with type two diabetes. Systemic lupus, psoriasis and HIV infection are associated with increased risk of coronary artery disease possibly mediated by chronic systemic inflammation. Smoking and hyperlipidemia increase the risk of coronary disease partly through the effects on vessel inflammation. Obesity, particularly obesity around the abdominal cavity, produces chemical agents that increase systemic inflammation.

Potential for treatment of inflammation to prevent heart disease

An exciting area in cardiac research currently is the potential to target inflammation to prevent or treat cardiac disease. It has been demonstrated that cholesterol lowering can improve outcome in some of these patients, but more promising may be the use of the medications that directly target the inflammatory process. Monoclonal antibodies which suppress inflammation have been used with great success in rheumatologic disease and studies are now beginning to be done in cardiac patients. The studies so far have mixed results and given the cost of these agents may not be easily applicable to much of the developing world. An older anti-inflammatory medication used for gout, Colchicine, has shown promise in reducing complications from heart attack, recurrent hospitalisations from heart failure and death in patients with established cardiac disease.

What can I do to reduce the risk of inflammation affecting my heart?

Currently we should look to identifying people at risk, by using traditional therapies, and following lifestyle changes. For patients who are known to have chronic inflammatory diseases particularly collagen vascular diseases, they should speak with their physicians about potential cardiac risk. There should be a low threshold for cardiac evaluation and treatment to lower the risk of heart disease and stroke. For the general population, several lifestyle measures are important including not smoking, regular aerobic exercise, trying to avoid becoming overweight (particularly with fat around the abdomen) and diets that include fruits, vegetables, grains, beans, nuts and fatty fish. For some patients testing for markers of inflammation and acting on the results may prove useful. Potentially in the future, medications that directly attack inflammation to prevent or treat cardiac disease may be part of our medical tool kit.

Dr Ernest Madu, MD, FACC and Dr Paul Edwards, MD, FACC are consultant cardiologists for Heart Institute of the Caribbean (HIC) and HIC Heart Hospital. HIC is the regional centre of excellence for cardiovascular care in the English-speaking Caribbean and has pioneered a transformation in the way cardiovascular care is delivered in the region. HIC Heart Hospital is registered by the Ministry of Health and Wellness and is the only heart hospital in Jamaica. Correspondence to info@caribbeanheart.com or call 876-906-2107.