Interventional cardiology

Access to angiography improving but high risk ACS patients missing out: CONCORDANCE

Whether patients  with ACS  present to a hospital with a catheterisation laboratory or one without does not influence the odds of a major cardiac event or death six months on, an audit reveals, for the first time suggesting that inequities in access to invasive coronary angiography are being overcome across more parts of the country.

The latest review of the long-running CONCORDANCE registry shows angiography rates were high overall – about 80% of patients presenting to hospitals with catheterisation labs underwent the procedure but even amongst those hospitals that were not catheterisation capable the number of patients that were sent on for angiography was close to 70% and far higher than in previous audits.

The comprehensive analysis of 8245 patients who presented with ACS to 43 Australian hospitals during 2009–2018 shows that while the availability of coronary angiography at the hospital of presentation influenced catheterisation rates the clinical characteristics of patients undergoing the procedure were similar for both hospital categories, which suggests that practice patterns and decisions to offer invasive treatment are similar in both settings.

Across both hospital settings the odds of in‐hospital MACE was higher for older patients, patients with diabetes, chronic renal failure, or dementia/cognitive impairment; it was also higher for patients diagnosed with STEMI or NSTEMI than for those diagnosed with unstable angina.

Meanwhile, the odds of in‐hospital death were higher for older patients, those with prior myocardial infarction, chronic renal failure, or dementia or cognitive impairment; and were higher for patients diagnosed with STEMI or NSTEMI than for those diagnosed with unstable angina

Speaking about the latest audit, Professor David Brieger, head of coronary care and coronary interventions at Concord Hospital in Sydney said the finding was ‘surprising.”

“We found that hospitals that didn’t have Cath labs on site were providing angiography for a higher proportion of their ACS patients than we’ve seen in previous audits we’ve done and that’s surprised us,” he told the limbic.

Despite differences in the proportions of patients who ultimately underwent catheterisation, outcomes for patients with ACS who presented to catheterisation‐capable and non‐capable hospitals were similar, suggesting that they are not significantly influenced by the availability of on‐site coronary angiography in the hospital of presentation, Professor Brieger explains.

“Whether you came from a hospital with a cath lab or one without if you had a certain clinical cluster you were equally likely to get an angiogram and similarly if you had a different cluster – if you were much higher risk – you were less likely to get an angiogram at both hospitals regardless of where you presented.”

But there is a caveat. While CONCORDANCE is the largest ACS registry in the country it does not include regional and remote hospitals, which generally do not have the sort of resources requited to collect data needed for registry participation.

“We did make a big effort to be as representative as we could however, the registry does represent perhaps better performing hospitals than general. We found that when we ran the SNAPSHOT registry around 10 years ago the CONCORDANCE hospitals tend to be better resourced because they’ve got the capacity to collect these types of data and even those that don’t have Cath labs are prob better resourced than many other comparable hospitals without cath labs.”

Nonetheless, angiography rates are on the up around many parts of the country regardless of whether the hospital to which patients presented had a catheterisation laboratory or not, suggesting that triage and transfer systems in hospitals enrolled in CONCORDANCE are overcoming previously documented inequities in access to invasive procedures.

“When we ran studies years ago, like the Heart Protection study for example in the early 200s and ACACIA a few years later, we didn’t see the angiography rates that we’re seeing now so in my mind there clearly has been an improvement in access to angiography for patients and that’s a great thing.”

The differences presumably reflect growing acceptance of coronary angiography as the standard of care for patients with ACS at high risk of cardiovascular events, and the increased capacity to transfer patients to catheterisation‐capable hospitals that contribute to CONCORDANCE registered hospitals, Professor Brieger notes.

“I think the data has become relatively consistent suggesting that, certainly high risk, ACS does benefit from an invasive management strategy and CONCORDANCE is representative of a relatively high risk population and systems of care have evolved across the country really to improve access to angiography

Interestingly  the audit reveals that it’s higher risk ACS patients that don’t go on invasive angiography. 

“It’s something we’ve seen all along and that is that we are still risk averse when we’re offering angiography to our patients if you look at the risk profile of the patients who went for an angiogram it was actually much lower than those who did not,” says Professor Brieger.

Whilst under certain circumstances it’s ‘totally appropriate’ not to offer an angiogram to all high risk patients – those who are approaching end of life or who have life affecting co-morbidities for instance notes Professor Brieger – the audit shows there were a number of patients who didn’t fall into that category but who did have features that increase the risk of a complication of an angiogram.

“We tend to shy away from performing risky procedures on these patients even though the amount that you gain from doing these procedures is greater because their absolute risk of ischaemic event is greater so it’s a focus of ours to try and enhance angiography among the higher risk patients who have the most to gain,” adds Professor Brieger when asked about  priorities for achieving lower long-term mortality in patients with ACS.

Other priorities include advancing efforts to understand the condition outside of traditional risk factors and the role of inflammation in ACS.

“We’re doing pretty well in coronary disease – mortality rates are falling, STEMI rates are falling and that’s related to primary prevention and better acute care but there’s still a lot that we don’t understand; there are still events occurring in patients despite optimal risk factor control; we still have events in patients who don’t have identified modifiable risk factors and there are newer avenues for investigation into coronary disease that I think are fruitful and exciting – things like looking at coronary inflammation and using drugs like  canakinumab and colchicine … I think that’s where the future lies – looking at these novel mechanisms,.”

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