Unblocking additional plaque or cholesterol-clogged coronary arteries with stents after a heart attack — instead of just the one that caused the heart attack — leads to a reduction in the risk of dying or having another heart attack, a multinational study involving B.C. experts and patients shows.
Experts predict the “landmark” study will have immediate implications for heart attack patients as interventional cardiologists will now stent additional coronary arteries with significant narrowing (more than 70 per cent) instead of just the culprit artery that caused the heart attack. There are three major coronary arteries and when heart attack patients have one blocked artery, it is not unusual to see blockages in the others, referred to as multi-vessel coronary artery disease.
The study began in 2013 at hospitals in 31 countries, predominately in Europe and North America. It was published in the New England Journal of Medicine and was presented as a late-breaking session at the World Congress of Cardiology in France.
The COMPLETE study, as it is called, involved 4,041 patients (200 in Vancouver) who were followed for about three years. All patients got stents in the culprit arteries as an emergency rescue measure. But in one arm of the study, half were then released from the hospital and prescribed the usual post-angioplasty medications while in the other study arm, patients had their other blocked arteries stented in what is called complete revascularization, either at the same time as the heart attack causing culprit stenting or within 45 days.
Deaths from heart disease, further heart attacks or related to the medical procedure occurred in 179 patients (8.9 per cent) in the complete revascularization group, compared to 339 (16.7 per cent) of those who had only one stent put in.
After a median followup of three years, the risk of a second heart attack or death from heart disease occurred in 7.8 per cent of the patients who had complete revascularization while it was 10.5 per cent in those who got one stent.
“In the past, the gestalt was you do an immediate angioplasty to open the culprit blocked artery and then do less with the other ones, put patients on meds and monitor them instead of fixing the additional blockages at the same time or right after,” said Dr. David Wood, the Vancouver co-principal investigator and director of the Vancouver General Hospital Cardiac Catheterization Lab.
“But in this study, the results show that doing more stenting, even within the first 45 days after the heart attack, was beneficial. There was a 26 per cent reduction in the patients’ risk of dying or having another heart attack.”
Dr. Shamir Mehta, the principal investigator of the study led by McMaster University and Hamilton Health Sciences, said the data shows that there are benefits to clearing all the arteries and no major downside to the additional procedures.
“Given its large size, international scope and focus on patient-centred outcomes, the COMPLETE trial will change how doctors treat this condition and prevent many thousands of recurrent heart attacks globally every year,” said Mehta, an interventional cardiologist and a senior scientist at the Population Health Research Institute.
Dr. John Cairns, a Vancouver cardiologist who is the former dean of UBC medical school and a study collaborator said: “(Additional) blockages should be fixed in the first 45 days after a patient’s initial heart attack.”
Leslie Carey was one of the trial participants. In 2015, the Burnaby resident had a heart attack while riding a bus to work,
Carey’s chest pains were so severe that he got off the bus and called 911. Paramedics quickly attended to him in a nearby parking lot, whisking him off to VGH.
Life was stressful at the time but his health was pretty good, or so he thought.
“I didn’t have high blood pressure or diabetes but I was taking meds on and off for cholesterol,” said the 58-year old marine administrator for the Royal Vancouver Yacht Club.
Right after a coronary artery was stented, Carey said he felt so much better. His chest pain was gone. Since he was randomly assigned to the trial arm of patients who would get further treatment, he then had another stent inserted into another partly blocked artery. And months later, yet another stent was added so he now has three stents propping open his major coronary arteries.
“I’m fully wired now,” said Carey.
About 20,000 B.C. residents have diagnostic angiograms and angioplasties — usually with stents — each year and another 2,000 have open heart surgery, which is indicated for more serious cases and for patients with diseases like diabetes, according to a Cardiac Services B.C. provincial registry.
Mehta said patients who had angioplasties were on the right medications to reduce their risk of a heart attack. No one should jump to the conclusion that the medications weren’t effective.
“We don’t know if the same benefit of angioplasty would be there if they were not on the medication. The angioplasty can be considered as an add-on to the medications to prevent further events.”
Mehta, Cairns and Wood agreed that doing more angioplasties on patients with heart attacks is not going to overburden the Canadian health care system. A future study may look at the economics of “front-loading” angioplasties and Cairns said he thinks there could be some cost efficiencies in addition to health benefits.
“We are well equipped in Canada to perform the additional procedures, particularly since the trial shows they can be done any time within 45 days of the index (first) heart attack,” said Mehta.
The median age of trial participants was about 62 and 80 per cent were male. Study authors said that is because more men have large heart attacks. About 50 per cent of study participants had high blood pressure and 40 per cent were smokers. Just under 40 per cent had high cholesterol.
The study cost over $14 million; $3 million came from the Canadian Institutes of Health Research and just over $11 million from Boston Scientific and AstraZeneca. The companies had no role in trial design, analysis or manuscript writing, according to the authors.