Daijiworld Media Network - New Delhi
New Delhi, Aug 4: A liberal blood transfusion strategy may reduce the risk of death or recurrent heart attack in patients with myocardial infarction and anaemia compared with a restrictive transfusion approach, according to a post hoc analysis of a large international randomised clinical trial.
The findings suggest that maintaining higher haemoglobin levels through earlier transfusion may provide greater overall clinical benefit despite a small increase in the risk of heart failure.
Determining the optimal haemoglobin threshold for blood transfusion after a heart attack has remained a challenge for clinicians, who must balance the potential reduction in recurrent ischaemic events against the possibility of fluid overload and heart failure.
To further examine this balance, researchers conducted a Bayesian post hoc analysis of data from the Myocardial Ischemia and Transfusion (MINT) trial.
The study involved 3,504 adults hospitalised with myocardial infarction and anaemia across 144 hospitals in six countries. Participants were randomly assigned to one of two transfusion strategies.
Under the restrictive strategy, blood transfusion was recommended only when haemoglobin levels dropped below 7-8 g/dL. The liberal strategy aimed to maintain haemoglobin levels above 10 g/dL through earlier transfusions.
Researchers evaluated the likelihood of benefit and harm using Bayesian statistical analyses based on three different prior assumptions.
The analysis found that the liberal transfusion strategy was associated with a 1.4 to 2.4 percentage point lower risk of death or recurrent myocardial infarction within 30 days compared with the restrictive approach, depending on the statistical model used.
The probability that the liberal strategy reduced the combined risk of death or heart attack ranged from 89.1 per cent to 98.8 per cent.
Researchers also estimated a 62.7 per cent to 90.4 per cent probability that treating 100 patients using the liberal strategy would prevent at least one death or recurrent heart attack.
The study, however, identified a modest increase in the risk of heart failure among patients receiving the liberal transfusion strategy.
Compared with the restrictive approach, the estimated increase in heart failure risk ranged from 0.2 to 0.6 percentage points. The probability of causing at least one additional heart failure event per 100 treated patients ranged between 13.3 per cent and 29.3 per cent.
Despite this increased risk, investigators concluded that the overall balance of benefits favoured the liberal transfusion strategy.
Based on their analysis, treating 200 patients with the liberal approach would be expected to prevent approximately five deaths or recurrent heart attacks while resulting in one additional case of heart failure.
The researchers said the findings are consistent with current clinical guideline recommendations and support consideration of a liberal transfusion strategy for selected patients with myocardial infarction and anaemia.
They emphasised that decisions regarding blood transfusion should continue to be individualised, taking into account each patient's clinical condition, cardiovascular risk and personal preferences alongside medical judgement.