Thirteen people who were in invasive procedure group died, compared with just six in the medication group.

BBC: 'Operations are best' for older hearts

But researchers said half of those deaths had occurred in patients who had been allocated to the invasive procedure group but were unsuitable for revascularisation or unwilling to have it.

BBC: 'Operations are best' for older hearts

The second group had a sham procedure, in which incisions were made but all muscles and nerves remained intact.

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