Metabolic syndrome is a cluster of conditions including high blood pressure, excess body fat around the waist, elevated insulin levels and abnormal cholesterol levels. Many people have more than one-and sometimes all-of these conditions, and the coexistence is not a coincidence, but a common underlying abnormality allows them to develop. Any of these conditions increases the risk of diabetes, heart attack and stroke, but the risk is greater when they are combined. This cluster of metabolic abnormalities is a significant risk factor for death during and immediately after bypass surgery. Also known as “Syndrome X”, metabolic syndrome is increasing in the Western world and is associated with insulin resistance. Insulin stimulates glucose (sugar) uptake into body tissues where it is utilized. In insulin resistance, tissues have a diminished ability to respond to the action of insulin. To compensate for resistance, the pancreas secretes more insulin. Insulin-resistant persons, therefore, have high plasma insulin levels yet are unable to store glucose so they also have high levels of blood sugar (diabetes). Patients with one of these problems should discuss the situation with their physician and may wish to be tested for the other conditions.