Anaemia in acute coronary syndrome associated with higher mortality: Insights from the UK MINAP Registry.
20 December 2016
By: Krishnaraj Rathod
colleagues recently published a paper using data from the UK MINAP registry. Although
their observation is not novel, this registry had 422,855 ACS patients, making
this one of the largest groups analysed for this condition. They had 27.7%
patients who were anaemic at presentation and the study found there was an
increased risk of death at 30 days (OR 1.28, 95% CI 1.22-1.35) and 1-year (OR
1.31, 95% CI 1.27-1.35) 1.
As we know
already, there arenít many guidelines or evidence to support the use of
pharmacotherapy in patients who are anaemic. It remains unclear from the
guidelines whether these patients should receive a blood transfusion and the
optimal transfusion strategy.
This study noted
that patients with anaemia were less likely to receive aggressive therapy than
patients without anaemia. For example, anaemic patients had a higher incidence
of taking aspirin and clopidogrel before arriving to the hospital compared with
those without anaemia (7% vs 5%; P<0.001), but there was a lower incidence
of dual antiplatelet therapy upon discharge (75% vs 79%; P<0.001). In
addition, there were lower rates of angiograms being performed in the anaemic
patients compared to those without anaemia (26% vs 38%; P<0.001) 1.
The reasons for
the increased mortality rate among anaemic patients is likely to be
multifactorial. Patients with anaemia were older and had higher rates of other
comorbidities. Although these co-variables were taken into account in the
analysis, as with all observational studies, there are bound to be unmeasured
confounding variables that could increase the risk of death.
So how do we try and manage patients presenting with
anaemia and ACS?
A meta-analysis of
10 studies that used a liberal transfusion strategy found an increased risk of
mortality in patients with acute myocardial infarction. This risk remained
independent of anaemia status 2.
strategies that are currently being practised to reduce the risk of bleeding
include performing PCI via the radial route, using closure devices
post-procedure and adjusting the doses of antithrombotic agents with renal
function and weight 3.
this study adds to the literature regarding the dangers of ACS in patients with
anaemia and these patients certainly fall into a very high-risk category. In addition, the effectiveness of correcting anaemia,
particularly via blood transfusion, has not been investigated thoroughly and
therefore targeted individual patient guided therapy may be more appropriate
than a generalised guideline for this cohort of patients.
- 1 Relationship
Between Anemia and Mortality Outcomes in a National Acute Coronary Syndrome
Cohort: Insights From the UK Myocardial Ischemia National Audit Project
Registry. Mamas MA, Kwok CS, Kontopantelis E, Fryer AA, Buchan I, Bachmann MO,
Zaman MJ, Myint PK. J Am Heart Assoc.
2016 Nov 19;5(11). pii: e003348.
- 2 Anemia and Acute Coronary
Syndrome: Time for Intervention Studies. Farhan S, Baber U, Mehran R. J Am Heart Assoc. 2016 Nov 19;5(11).
- 3 Association of blood
transfusion with increased mortality in myocardial infarction: a meta-analysis
and diversity-adjusted study sequential analysis. Chatterjee S, Wetterslev J,
Sharma A, Lichstein E, Mukherjee D. JAMA
Intern Med. 2013 Jan 28;173(2):132-9.
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