Metabolic Syndrome is a strong factor in the development of the Aortic Stenosis
Metabolic syndrome is the name given to a collection of disorders having to do with the body’s metabolism. All of these disorders are related to a primary disorder of insulin resistance . Metabolic syndrome occurs in people who are genetically disposed to insulin resistance, and who then allow themselves to become sedentary and overweight. It is estimated that 25 percent of the American population have metabolic syndrome.
The presence of metabolic syndrome greatly increases a person’s chances of developing overt diabetes, a host of cardiovascular (heart and blood vessel) conditions including heart attack, stroke, kidney disease, and premature death.
Metabolic Syndrome and Aortic Stenosis
One of the cardiovascular conditions that can result from metabolic syndrome is called “aortic valve stenosis” or “aortic stenosis.” Aortic stenosis is one of the most common cardiovascular diseases in North America. Aortic stenosis that occurs later in life can be due to age and the wear and tear of normal heart function.
Researchers have discovered that metabolic syndrome is prevalent in patients who are diagnosed with aortic stenosis, but more than this, metabolic syndrome has been found to be a strong factor in the development of the disease.
Aortic stenosis progresses at twice the rate in those with metabolic syndrome. Unfortunately, those with metabolic syndrome also have worse outcomes.
What is the Aortic Valve?
The aortic valve, also called a semilunar valve, lies between the left ventricle (major pumping chamber of the heart) and the aorta (largest artery in the body). When it is working properly, the heart pumps and the aortic valve opens, allowing blood to flow freely from the left ventricle into the aorta to circulate throughout the body. It then closes to prevent a back flow of blood into the heart.
What is Aortic Valve Stenosis?
In aortic stenosis, the aortic valve develops a hard buildup similar to plaque (buildup of fats, cholesterol, calcium and cell debris) that causes hardening and narrowing of the arteries (atherosclerosis). The aortic valve hardens and narrows. This hardening prevents the valve from opening properly. The flow of blood is then reduced, and pressure builds up within the left ventricle (main pumping chamber of the heart). The heart has to work harder to pump blood throughout the body.
How Does Metabolic Syndrome Cause Aortic Stenosis?
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One thing that happens with metabolic syndrome is the low-density lipoproteins - also known as LDL (bad) cholesterol - become smaller and more dense. These smaller LDL particles are susceptible to oxidation (a reaction with oxygen causing a chemical change) and become damaged. It is thought that these damaged smaller particles enter more easily into the leaflets of the aortic valve starting the hardening process. The damaged LDL particles also cause inflammation. They carry other particles with them such as C-reactive protein, which enhances the hardening or stenosis of the aortic valve. C-reactive protein (CRP) is a marker in the blood that is released when inflammation is occurring in the body. It is now thought that both the inflammation and the CRP particles are involved in the process of heart disease.
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High-density lipoproteins or HDL (good) cholesterol has antioxidant and anti-clot (antithrombogenic) effects. But in metabolic syndrome, the levels of HDL cholesterol are reduced. Instead of being able to prevent the oxidation that happens to the small LDL particles, the LDL particles have free reign to promote inflammation and hardening of the aortic valve.
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Abdominal obesity that is present in most people with metabolic syndrome increases insulin resistance. Insulin resistance is responsible for the metabolic changes in metabolic syndrome that promote heart disease. These include increased blood sugar, insulin, high LDL cholesterol and triglyceride levels, as well as high blood pressure. Abdominal fat also increases inflammation in the body. All of these disorders together contribute to the development of aortic stenosis.
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Adiponectin is a protein in the body that reduces inflammation and prevents the formation of deposits on the inside of the artery walls and the aortic valve. When a person is obese or has metabolic syndrome, this protein is decreased in the body. When the body loses this protection, hardening of both the arteries and the aortic valve is escalated.
Signs and Symptoms
The the three classic symptoms of aortic stenosis are shortness of breath (dyspnea), fainting (syncope) and chest pain (angina). You may find that you can’t walk as far or climb the stairs without becoming short of breath. Your doctor may hear an extra heart sound or a murmur. This is the sound of blood being forced through the hardened narrow aortic valve.
If you experience any of these symptoms, an echocardiogram is a fairly simple test that your doctor can order. It provides a two dimensional view of the movement of the valve and any thickening that might be occuring. Anyone who is diagnosed or is suspected of having aortic stenosis should be screened for metabolic syndrome.
