In the context of the ongoing and increasingly sterile debate about the pros and cons of statins to lower cholesterol, it is refreshing to hear something new.
At a recent meeting in Quebec, researchers made the case that it might be more sensible to better identify individuals at heightened risk of heart attacks and strokes by using a more accurate screening test. Advice and interventions to reduce risks could then be more precisely targeted.
Hardening or furring of the arteries, also known as atherosclerosis, is due to the accumulation of calcium and cholesterol in plaques on artery walls. There are two broad categories of atherosclerotic plaques: stable and unstable (also known as vulnerable). Unstable plaques are more likely to rupture and cause a blood clot that blocks the supply of blood to the heart (triggering a heart attack) or the brain (triggering a stroke).
Currently, assessing an individual’s risk of stroke or heart attack relies heavily on computer programmes that grade people according to a number of features including age, sex, ethnicity, cholesterol level, blood pressure, smoking status and family history. But a number of studies have shown that one in five individuals who have had a heart attack might not have been assessed as being at high or moderate risk using the currently available computer programmes before the heart attack occurred.
Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an enzyme that seems to play a role in the progression of early, relatively stable atherosclerotic plaques to unstable rupture-prone plaques. Moreover, high levels of Lp-PLA2 are present in unstable rupture-prone plaques, and it appears that Lp-PLA2 is released from these plaques into the circulation where its levels can then be measured by a simple blood test.
The Lp-PLA2 blood test has now been approved by the U.S. Food and Drug Administration for assessing the risk of stroke and coronary artery disease, and has also recently become available in the U.K.
Individuals with a raised Lp-PLA2 result might be just the group that should be the major target group for treatment with statins in order to lower their risks. As the current approach to commencing treatment with statins is somewhat arbitrary – ignoring the linear correlation between heart attacks and cholesterol levels – it is further proposed that if the Lp-PLA2 result is high, statin treatment should be considered even if a person has been told that their cholesterol reading is ‘normal.’
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