With the rise of metabolic diseases such as hypertension, diabetes, and hyperlipidemia increase in Korea, the prevalence of myocardial infarction and atherosclerotic cardiovascular diseases are also on the rise.

The mortality rate of myocardial infarction is in the 20-30% range when it occurs for the first time, but the mortality rate increases sharply to 68-85% when it recurs, which is why efforts to prevent recurrence are being stressed now.

In particular, one of the hot topics in treatment is how to manage LDL cholesterol, which is known to be an important factor in preventing the recurrence of atherosclerotic cardiovascular disease (ASCVD).

In recent years, treatment options have become more diverse and multiple approaches have been proposed. Dr. Dong-Oh Kang, Professor of Cardiology and Cardiovascular Center at Korea University Guro Hospital, emphasized the need to effectively lower LDL cholesterol levels in high-risk patients.


“New drugs have changed the approach to LDL cholesterol management in high-risk patients”

In severe cases of acute myocardial infarction, stenting or balloon angioplasty is performed to open up the blood vessel, as it is an emergency treatment for blocked blood vessels or low blood flow.

However, these procedures are reactive, and it is important to use medications to prevent the same event from happening again.

“It is important for patients who have had a myocardial infarction to use drugs to prevent further accumulation of atherosclerotic plaque and narrowing of the artery,” said Professor Kang. ”Lowering cholesterol to inhibit the progression of atherosclerotic plaque and preventing blood clots has become a key treatment.”

This is why one of the most important topics in recent guidelines is to what level LDL cholesterol should be lowered in very-high-risk patients.

Both domestic and international academic societies have proposed a strict management standard for patients with a history of atherosclerotic cardiovascular disease, with LDL cholesterol targets of less than 55 mg/dL and at least 50% lower than baseline.

“The past guidelines suggested that LDL cholesterol levels could be as low as 100 mg/dL, but more potent drugs have come in a variety of combinations.” said Professor Kang, “As lowering LDL cholesterol levels has been shown to reduce the risk of atherosclerotic cardiovascular disease, even lower levels are now being recommended.”

According to Kang, the suggested LDL cholesterol level for high-risk patients was less than 70 mg/dL in the 2010s, but by the late 2010s, patients with coronary artery disease or at very-high-risk were advised to lower their LDL cholesterol level to less than 55 mg/dL and at least 50% from baseline.

In particular, the European guidelines suggest lowering LDL cholesterol levels to less than 40 mg/dL for patients with acute coronary syndrome who have had a recurrent event within the last 2 years.

“Cardiologists who see patients with more severe acute myocardial infarction or patients undergoing procedures seem to be in agreement with the lower LDL cholesterol targets. However, some have concerns about lowering LDL cholesterol levels below 55 mg/dL or 70 mg/dL.”

Diversification of treatment options, including PCSK9 inhibitors...“Strategy will change depending on reimbursement status”

As Professor Kang noted, the lower LDL cholesterol target levels have been accompanied by the emergence of drugs that can effectively lower the levels to such targets.

In the past, statins, which inhibit the synthesis of cholesterol in the liver, were the only drugs available to lower LDL cholesterol levels, but more strategies became available with the introduction of ezetimibe, which inhibits cholesterol absorption in the intestine, including statin and ezetimibe combinations.

Then, the entry of monoclonal antibody drugs such as Repatha (evolocumab), a PCSK9 inhibitor, into the reimbursement system has transformed the clinical landscape.

Currently, PCSK9 inhibitors are used in patients with myocardial infarction whose LDL cholesterol levels have not dropped sufficiently despite the use of high-intensity statins and ezetimibe.

“It's important to monitor the dose escalation during initial therapy,” said Kang. “If LDL-C targets are not met, the dose should be increased and the patient reevaluated. If the maximum dose is not effective, a PCSK9 inhibitor such as Repatha, which has a faster LDL cholesterol lowering rate and is more potent, may be considered.”

“In terms of Repatha’s effect, 19 out of 20 people will have lower LDL cholesterol level maintained, even at 30 mg/dL. In patients who had low LDL cholesterol, to begin with, we see reductions to less than 10 mg/dL.”

In the long term, the introduction of oral bempedoic acid and injectable siRNA therapies is expected to further expand treatment options.

In addition to access to treatments based on patient condition, Professor Kang predicts that treatment approaches will change based on the drug’s reimbursement status.

“As more effective treatments will continue to be developed, we expect more and more combination options to emerge, and it is necessary to prescribe them considering the patient's condition and the characteristics of each drug,” said Kang. ”Since there are various drugs, their use will likely be determined by how reimbursement is applied in high-risk patients.”

In addition to secondary prevention, Kang emphasized the need for policy promotion to screen and manage patients before they become high-risk.

“Even though people are sufficiently screened and informed about their risk factors through health screenings, they often overlook them and look back in retrospect after they become ill. It is necessary to always receive screening and make efforts to properly treat or improve lifestyle habits from the primary prevention stage.”