ATACH-2 disputes intensive BP control benefits in acute ICH
medwireNews: Reducing systolic blood pressure (BP) to less than 140 mmHg has offered no benefits over standard care for patients with acute intracerebral haemorrhage (ICH) in the ATACH-2 trial.
In fact, the trial was halted for futility after the enrolment of 1000 patients (the target was 1280), by which point disability or death had occurred in 38.7% of patients treated to a BP target of 110 to 139 mmHg and 37.7% of those treated to a standard target of 140 to 179 mmHg.
This 1 percentage point difference, in favour of the standard-treatment group, fell far short of the 10 percentage point difference the researchers had powered the trial to detect, reasoning that anything smaller would be “viewed as insufficient for broad acceptance of a new intervention.”
The patients all had a haematoma volume of less than 60 cm3 and a Glasgow Coma Scale score of at least 5. Their treatment, using intravenous nicardipine, was started within 4.5 hours of symptom onset.
The findings, which appear in The New England Journal of Medicine, contrast with those of INTERACT2, which recruited around 1800 patients. It just missed its primary endpoint of reduced death or disability in the intensive treatment group, with an odds ratio of 0.87 and a 95% confidence interval of 0.75–1.01, but the key secondary endpoint of the distribution of scores on the modified Rankin Scale was significant.
Besides the number of patients recruited, there were several notable differences between the two trials, as highlighted by ATACH-2 investigator Adnan Qureshi (University of Minnesota, Minneapolis, USA) and colleagues.
These include earlier treatment initiation and higher average pretreatment BP in ATACH-2, as well as a lower rate of treatment failure (ie, failure to attain target BP range) and lower attained BP in the intensive-treatment group.
The researchers note that they had powered their trial in anticipation of a 3-month death or disability rate of 60%, but the actual rate was more than a third lower. They say this may have been partly due to patients having favourable baseline characteristics, with more than half having unimpaired consciousness, but also suggest that the consistent level of care provided within a clinical trial may have helped.
“Although additional studies are needed, we may have seen a global benefit of careful monitoring and standardized care for patients with acute cerebral hemorrhage”, said Qureshi in a press statement.
As well as being standardised, care was rarely withdrawn, compared with a reported rate of 34% in clinical practice, say the researchers.
And they add: “It is also possible that the blunting of fluctuations in the systolic blood-pressure level in patients with intracerebral hemorrhage and an acute hypertensive response may exert a therapeutic benefit that is independent of the magnitude of lowering the systolic blood-pressure level.”
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