A New Risk Factor for Heart Attack and Stroke

Why is it that most patients who have had a stroke or a heart attack don't have any of the normal risk factors, such as high cholesterol or high blood pressure, that are generally associated with cardiovascular risk? The answer, it seems, may be a risk factor that has been missed until now; a condition called clonal hematopoiesis of indeterminate potential, or CHIP.

In essence, CHIP is a condition in which some of the stem cells in bone marrow that initiate the production of white blood cells (WBCs) begin to mutate, resulting in the increased production of white blood cells carrying the mutation. Patients with an increased number of these mutated WBCs in their blood are 40-50% more likely to die of a stroke or a heart attack within 10 years. Apparently, the risk of developing CHIP goes up sharply with age. Although only about 20% of 60-yr-olds have developed CHIP, half of all 80-yr-olds have the condition. It's almost as if CHIP is a normal consequence of aging.

And how might CHIP contribute to cardiovascular disease risk? Researchers have long speculated that chronic inflammation may contribute to the development of blood vessel-blocking atherosclerosis. And its possible that chronic inflammation is initiated by increased numbers of inflammatory WBCs in the blood.

Doctors are not advising their patients to be tested for CHIP yet, because at the moment there is nothing to be done about it even if you do test positive. At least not yet; perhaps some day there will be.