The collaborative research between Victoria University of Wellington and Capital and Coast District Health Board (C&C DHB), highlights an important issue for New Zealand heart attack sufferers and their medical treatment.
When patients are admitted to hospital with a heart attack, standard practice is to put them on antiplatelet drugs, such as aspirin and clopidogrel. These drugs make the platelets (the cells in the blood that form clots) less ‘sticky’, improving blood flow.
C&C DHB cardiologist Dr Scott Harding says that although the drugs have been shown to significantly improve patient outcomes, overseas studies have found that patients do not respond equally to these drugs.
“As many as 25-30% of patients tested overseas are not receiving an adequate benefit from this drug treatment. That means they have a higher risk of experiencing another heart attack or dying following their stay in hospital.”
In the New Zealand study, 38% of patients overall did not have an adequate response to the antiplatelet drugs after a heart attack.
The non-response rate for Maori and Pacific Island patients was very high with 57% not demonstrating an adequate response.
“This is an important finding as Maori and Pacific Island patients have a high rate of cardiovascular disease and poor outcomes following heart attacks. This finding could partially explain these poor outcomes,” says Dr Harding, who is also an adjunct professor at Victoria University.
Additional aspects of the study also found that the drug dose and the presence of diabetes affected the patients’ response to the drug.
The study conducted by Dr Harding and Victoria PhD student Lisa Johnston is the first New Zealand-based study to examine what proportion of patients suffering a heart attack is not being effectively treated with the standard drug approach.
“You can’t always extrapolate data from international studies and apply it to New Zealand. We have a unique population that means results overseas aren’t necessarily the same for us,” says Miss Johnston.
Dr Harding and Miss Johnston also tested a newly developed antiplatelet drug called Prasugrel, which was shown to be highly effective in patients that who had not responded adequately to the older drugs. Their findings suggest that certain at-risk groups such as Maori and Pacific Islanders may benefit from receiving Prasugrel.
The findings were presented the annual meeting of the Cardiac Society of Australia and New Zealand at the weekend.
The study itself was conducted by Lisa Johnston, one of the first PhD students working at the new Clinical Research Lab at Wellington Hospital under the collaboration between C&C DHB and Victoria University. Her work was supervised by Dr Scott Harding and Victoria Associate Professors Dr Anne La Flamme and Dr Peter Larsen.