The notion that soft plaque is more likely to rupture and cause heart attacks than hard calcium deposits in coronary arteries may be wrong, said researchers from Intermountain Medical Centre Heart Institute in the US.
Atherosclerosis is caused when plaque builds up in the arteries, narrowing and hardening them.
"We previously thought the lipid-laden soft plaque was more likely to rupture and cause heart attacks, but based on our new research, it's more the calcified plaque that appears to be associated with adverse cardiovascular events" said Brent Muhlestein, of Intermountain Medical Centre Heart Institute.
Unexpectedly, proportionately higher quantities of calcified plaque best predicted major adverse coronary events, while soft plaque did not, researchers said.
The research reflects more long-term findings after patients were followed for an average of nearly seven years to see if their plaque composition had predicted whether they'd have a cardiac event.