A multimillion-dollar international study appears to have settled a long-running controversy about the treatment of patients with blocked arteries.

The study, named ISCHEMIA (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches), found that – for patients with severe but stable heart disease – there is no difference between undergoing dangerous and painful bypass surgery, and relying simply on medications (such as aspirin and statins) and lifestyle changes, to ward off death or heart attack.

The common insertion of artery-widening stents was also found to provide a life-saving benefit that couldn’t be achieved by drug therapies and lifestyle changes.

In other words, a pill and a healthy lunch and a walk in the sunshine has the same life-saving, heart-protecting capability as going under the knife.

The consequences of this study

If the study is truly “practice-changing” as it’s being widely described, the fallout will affect how millions of people are treated for ischaemic heart disease.

Also known as coronary artery disease, it is the leading cause of death in Australia for both males and females (about 20,000 dead in every year), and the leading cause of death in the world (8.76 million deaths worldwide in 2015), according to the Australian Bureau of Statistics.

Ischaemic heart disease, also called coronary artery disease, is caused by the build-up of plaque (fatty material) in the heart’s arteries, causing them to narrow. This build-up, called atherosclerosis, causes reduced flow of blood and oxygen to the heart (ischaemia), which can lead to many serious acute and chronic health problems.

Surgery helps pain relief, but doesn’t cut death risks

Led by researchers from NYU Grossman School of Medicine and Stanford University, the study found that invasive procedures to unclog blocked arteries (more often by the insertion of a stent, a mesh tube that props open a blood vessel after artery-clearing angioplasty) was useful for patients with symptoms of angina, the chest pain caused by restricted blood flow to heart muscle.

Open heart surgery or stent insertion led to better symptom relief and quality of life that persisted for four years.

However these strategies had no impact in reducing the rate of occurrence of cardiovascular death, heart attack, hospitalisation for unstable angina, hospitalisation for heart failure, or resuscitation after cardiac arrest.

There was no benefit at all in people without chest pain.

Big money and corporate interests under threat

The Washington Post described these findings as “the latest entry into a long and contentious argument over how to treat artery blockages, one that has pitted powerful factions of American heart specialists against each other.”

The paper also noted that, with the use of widespread use of stents called into question, “so much is at stake… companies that make stents are multibillion-dollar enterprises; the procedures are a major income stream to interventional cardiologists and hospitals; and many people who have stents credit their good health to the procedure.”

One doctor told The New York Times  the US could save more than US $775 million a year (more than $1 billion AUD) “by not giving stents to the 31,000 patients who get the devices even though they have no chest pain.”

How they did it

The study randomly assigned 5179 patients at 320 sites in 37 countries to receive one of the two treatment strategies after a stress test indicated they had heart disease: an invasive procedure, coupled with medication and lifestyle changes, or medication and lifestyle changes without intervention.

For the study, “invasive” treatment meant routine catheterisation, a procedure that slips a tube-like catheter into an artery in the groin or arm, and threads it through blood vessels to the heart.

This was followed by revascularisation when suitable – in most cases involving delivery of a balloon through the catheter to open a vessel (angioplasty), followed by the placement of a rigid stent.

In other cases, improved blood flow was accomplished by cardiac bypass surgery, where another artery or a vein is used to go around (bypass) the area of blockage.

There was an average four-year follow-up.

In the ISCHEMIA study, patients were randomised into one of two groups: a conservative strategy (medications and changes to diet and exercise) or an invasive strategy such as a stent or open-heart surgey plus the medication and lifestyle changes. Illustration: NYU Langone staff

According to a prepared statement from the researchers:

“By year two, the event rate for the study disease endpoints was roughly the same between the two approaches (9 per cent versus 9.5 per cent).

By four years, the rate of events was 2 percentage points lower in patients treated with heart procedures than in those that received medications and lifestyle advice alone (13.3 per cent with invasive versus 15.5 per cent). Overall, say the investigators, the trend shifts over time showed no significant evidence of a difference in rates between strategies.”

Among those with daily or weekly angina at the start of the study, 50 per cent of those treated invasively were angina-free after a year, compared to 20 per cent of those treated with medications and lifestyle advice alone.

 An Australian expert’s opinion

The results of the study were presented November 16 at the American Heart Association’s Scientific Sessions 2019 in Philadelphia. Heart Foundation chief medical adviser and cardiologist Professor Garry Jennings was among the many heart specialists from around the world that attended.

Professor Jennings, responding to questions by email, told The New Daily: “This study does confirm previous studies with similar findings and the evidence base has been growing that best practice medical therapy can match the results of interventions for most people with stable angina.”

He said that previous studies were smaller and subject to both “scientific criticism and push back from the interventional field.” ISCHEMIA, however, is “adequately powered” and has been very well accepted so far.

He said: “It will be most interesting to see how much this impacts on practice as the existing evidence prior to ISCHEMIA was strong albeit not definitive but does not appear to have reduced the number of interventions for stable angina.”

How will patients respond to this news – and will the study lead to a change in clinical standard practice?

“A key factor is the alignment of patient wishes and practitioner incentives. When people see a picture of their narrowed coronary artery they want something done about it and they want it now,” Professor Jennings said.

“Misleading adverse publicity about statins does not help and to many patients lifelong medications and lifestyle measures seem mundane.
No doubt funders will be alert to these data and they are in a position to drive down utilisation of expensive procedures when simpler measures achieve similar outcomes.”

Professor Jennings said it was important to note the interventional arm did reduce persistent angina.

“It is also important that the evidence for interventions for acute cardiac syndromes, especially STEMI (ST-Elevation Myocardial Infarction, a serious kind of heart attack), has gone the other way with clear benefit for early intervention.”

What might the study mean in terms of costs of treatment?

“Clearly the impact is likely to be substantial if there is a big shift away from coronary interventions in people with exertional angina.”