Anaemic patients with acute coronary syndrome (ACS) receive less evidence-based medical therapies than other patients, which likely contribute to their poorer outcomes, an Australian study shows.
An analysis of more than 8,000 patients from the CONCORDANCE registry found 21.7% were anaemic on presentation with ACS.
These patients were typically older and had more comorbidities than the non-anaemic group but their in-hospital management and outcomes were also significantly different.
The study found anaemic patients presenting with STEMI were less likely than other patients to receive reperfusion with either thrombolytic therapy (22% v 33%) or primary PCI (45% v 51%).
When a coronary stent was used during primary PCI, it was less likely to be a drug eluting stent in the anaemic group compared to the non-anaemic patients (45% v 54%).
For all ACS patients, STEMI, non-STEMI and unstable angina, anaemic patients were less likely to receive coronary angiography (63% v 86%), PCI (30% v 52%) and drug eluting stents (50% v 58%).
Anaemic patients were less likely to be prescribed heparin (82% v 88%), aspirin (94% v 97%), dual antiplatelet therapy such as aspirin plus prasugrel or ticagrelor (2% v 5%; 11% v 20%) or glycoprotein IIb/IIIa inhibitors (6% v 15%).
Anaemic patients also had more complex hospital stays and in-hospital events such as cardiogenic shock (5% v 2%), recurrent ischaemia (13% v 8%) re-infarction (4% v 2%) major bleeds (13% v 7%) and death (7% v 3%).
The study authors said there was general agreement that the management of ACS patients should incorporate anaemia into an overall PCI strategy but that there were no guidelines directly addressing this common clinical dilemma.
“Ultimately the difficulty remains in elucidating the exact drivers of poor outcome in anaemic patients given this particular cohort is not included in clinical trials.”
“However, the observation that the poor outcomes in our cohort were only partly corrected following adjustment for baseline clinical characteristics, highlights the importance of ensuring these patients are at the very least considered for prognostically important therapies.”
“We would suggest that this cohort requires further focused study to determine whether more active treatment in the acute phase of their presentation will improve outcomes.”
Lead author Professor David Brieger told the limbic the bleeding risk in patients with anaemia was not fully understood and not always amenable to therapy in a timely manner.
“When we have the opportunity we will correct the anaemia before coronary procedures but in emergencies such as STEMI it is often not possible to correct the anaemia before proceeding to intervention,” he said.
“I think the more we learn about these patients the better; as we gain access to larger patient level datasets through the EMR and improved data linkage strategies we will gain a better understanding of the factors that drive and ameliorate risk in these populations.”