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| ACE comes up trumps for CHD |
12-Apr-2007 |
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By Rebecca Jenkins
ACE inhibitors confer greater protection against coronary heart disease than angiotensin receptor blockers, according to a major Australian review.
A meta-analysis of 26 major trials that involved either an ACE inhibitor or angiotensin receptor blocker as one treatment arm found each class provided comparable blood pressure reduction, which correlated with reductions in risk of stroke, CHD and heart failure.
But ACE inhibitors provided an additional 9% relative risk reduction in CHD, even in the absence of blood pressure reduction — an effect not seen with angiotensin receptor blockers, researchers found.
“These findings therefore suggest that the coronary disease prevention afforded by a blood pressure-lowering regimen may be determined by the choice of agent as well as the size of the blood pressure reduction achieved,” they said.
“Maximisation of the benefit may therefore be achieved with a regimen that includes an ACE inhibitor together with other drugs in an effort to optimise the size of the blood pressure reduction achieved.”
Lead author Dr Fiona Turnbull, of the George Institute for International Health in Sydney, said the topic has been contentious for a long time, with much debate about whether ACE inhibitors or angiotensin receptor blockers were the superior class.
Writing in the Journal of Hypertension (May), Dr Turnbull and her co-authors said there had been uncertainty as to whether mechanisms independent of blood pressure also affected treatment outcomes.
“This is the first major study that’s used so many trials and fairly sophisticated techniques to show that firstly an independent effect does exist — although it’s small in relation to the total benefit from blood pressure reduction — and it’s not there for angiotensin receptor blockers,” Dr Turnbull told Australian Doctor.
The authors noted that although no such effect was observed for angiotensin receptor blockers, the confidence limits were too wide to exclude a modest effect.
Professor Phil Harris, director of cardiology services with Sydney South West Area Health Service, said some of the information that the drugs had benefits beyond blood pressure reduction came from pharmaceutical companies keen to distinguish these drugs from other blood pressure-lowering agents.
“I think the major message is that the primary effect ... is in fact due to blood pressure lowering,” he said.
“It’s very important confirmatory evidence because there’s been a debate.”
Professor Henry Krum, cardiologist and pharmacologist at Melbourne’s Monash University, said the issue of whether either class had an effect independent of blood pressure lowering had been contentious, with mechanisms difficult to elicit.
But he said it was reassuring the study did not identify any increase in cardiovascular events with angiotensin receptor blockers, which some researchers had suggested could be a concern among post-MI patients.
However, Professor Krum said the findings confirmed his preference for ACE inhibitors.
“The fact there is additional effect is probably even more reason to still think ACE inhibitor as first option,” he said.
Journal of Hypertension 2007; 25:951-58.
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