Heart Attack Risk Includes Normal Cholesterol Levels

A new study suggests statin eligibility be based on a person's overall cardiovascular disease (CVD) risk, and not cholesterol levels.

Researchers at the Minneapolis Heart Institute, and Cedars-Sinai Heart Institute conducted a prospective study involving 1,062 consecutive ST-segment elevation myocardial infarction (STEMI) patients (mean age 63.7 years, 72.5% male), of which 71.7% did not have any known CVD prior to STEMI. The researchers determined pre-STEMI statin eligibility, both according to previous Third Report of the Adult Treatment Panel (ATP3) and newer American College of Cardiology/American Heart Association (ACC/AHA) 2013 guidelines.

The researchers evaluated demographics, low-density lipoprotein (LDL) cholesterol levels, CVD risk factors, medication use, and outpatient history over the two years prior to STEMI. The results revealed that only 62.5% and 19.3% of individuals with and without prior CVD were taking a statin before STEMI, respectively. In individuals not taking a statin, median LDL cholesterol levels were low, with only 38.7% of patients statin eligible according to ATP3 guidelines. Conversely, 79% would have been statin eligible according to the 2013 ACC/AHA guidelines.

The researchers also found that less than half of individuals (both with and without prior CVD) had seen a primary care provider during the two years prior to STEMI. According to the researchers, the results are in line with a previous study that showed that use of known preventive CVD medications prior to STEMI was low, with only 7.8% of individuals taking aspirin and a statin before their event. The study was published on April 12, 2017, in the Journal of the American Medical Association (JAMA).

“Heart disease is a multifactorial process, and factors others than cholesterol, like smoking or high blood pressure, can raise your risk even if your cholesterol is normal. In fact, we found that cholesterol levels in this group of individuals were quite average,” said lead author cardiologist Michael Miedema, MD, MPH, of the Minneapolis Heart Institute. “The more recent cholesterol guidelines are clearly a big step in the right direction, but we need to have better systems and incentives in place to get patients the assessment and treatments that could potentially be life-saving.”

Statin therapy remains the mainstay treatment of elevated cholesterol, substantially lowering the risk of myocardial infarct (MI) in both primary and secondary prevention; this benefit is largely independent of baseline LDL. Prior data have shown that LDL, although a clear CVD risk factor, does not improve discrimination for future CVD events, when added to age and other traditional risk factors. In contrast to the ATP3 guidelines for the treatment of cholesterol, which relied heavily on LDL levels, the 2013 ACC/AHA cholesterol guidelines endorse a strategy recommending statin allocation largely based on absolute CVD risk.