A 10-year study by researchers from the Mayo Clinic in Minnesota, US, found that in each year of the study, TIA patients had a 1 per cent risk of MI - twice that of patients who had never had a TIA. TIA patients aged under 60 years had 15 times higher MI risk than patients who had never had a TIA.
Researchers examined data from 456 patients with an average age of 72, diagnosed with a TIA between 1985 and 1994.
Patients were followed up after 10 years. On average there was five years between a patient's first TIA and MI.
Risk of mortality also increased. TIA patients who later had an MI were then three times more likely to die during the follow-up period than those who did not have an MI.
Study lead Dr Robert Brown Jr of the Mayo Clinic said: 'Healthcare providers should be mindful of the increased risk for MI after TIA.'