Opening Up More Arteries, and More Possibilities

A landmark study has found that stenting narrowed non-culprit arteries after a serious heart attack can reduce the risk of future heart attacks.


In the aftermath of a serious heart attack, patients are ushered into the operating room to open up the clogged artery with a stent, restoring blood flow to the heart.

But with the culprit blockage gone, doctors are still left with a big question: do they perform another procedure to stent other narrowed arteries they find? Or do they go the more conservative route and send their patients home with medication to deal with the other potential blockages?

It’s not an easy question because the risks of additional surgical procedures could be significant for patients in recovery, especially if they are older or have other medical conditions. And while non-culprit partial blockages are discovered in about half of patients who have had a serious heart attack, they could be stable, meaning that stenting them preventatively would not provide a benefit.

A landmark international study, led by researchers at McMaster University in collaboration with 140 hospitals across 31 countries, shows that routinely opening all blockages leads to better outcomes than opening only the one blockage that led to the heart attack.

Not only did the routine stenting of non-culprit blockages lead to a 26 percent reduction in risk of death or recurrent heart attack when combined with medication, there were no major side effects versus treating with medication alone.

The study, known as the COMPLETE trial, was published in the New England Journal of Medicine.

A total of 4,041 heart attack patients were recruited to the study with 70 percent narrowing of multiple coronary arteries. Half were randomly assigned to receive medication after stenting the culprit blockage, and the other half received both medication and a stent in each blocked coronary artery.

After a follow-up at a median three-year mark, 10.5 percent of patients with non-culprit blockages treated with medication only had died or experienced a second heart attack; this compares with only 7.8 percent in patients who also received multiple stents.

The reduction in future complications grows when factoring in other possibilities, like severe chest pain that then requires a repeat stenting procedure. The risk of other major side effects, like stroke and major bleeding, were equivalent in both groups.

Notably, the second stenting procedure for the non-culprit blockages doesn’t need to be done immediately. The study waited up to 45 days after the primary surgery before going ahead with the second procedure, giving patients in recovery a chance to stabilize first.

“Given its large size, international scope and focus on patient-centered outcomes, the COMPLETE trial will change how doctors treat this condition and prevent many thousands of recurrent heart attacks globally every year,” said lead author Shamir R. Mehta, professor of cardiology at McMaster University, in a statement.

It’s a clear result that doctors can use to guide their clinical practice immediately. And with coronary artery disease being the leading cause of death worldwide, it could have a major global impact.

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Karyn Ho is a science animator and engineer who thrives at the interface between science, engineering, medicine, and art. She earned her MScBMC (biomedical communications) and PhD (chemical engineering and biomedical engineering) at the University of Toronto. Karyn is passionate about using cutting edge discoveries to create dynamic stories as a way of supporting innovation, collaboration, education, and informed decision making. By translating knowledge into narratives, her vision is to captivate people, spark their curiosity, and motivate them to share what they learned.