More than half of heart attack patients with a blocked artery were not treated with primary angioplasty in UK and treatment methods varied in different parts of the country, new research has revealed.

The Myocardial Ischaemia National Audit Project found that in some parts of the UK patients were prescribed clot-busting drugs instead of being given primary angioplasty.

Figures showed that 47% of patients in England received the stent operation treatment while in Cheshire and Merseyside hospitals only 5% were operated on, The Telegraph reports.

Last year, the UK government ordered that majority of the patients should receive the stent operation within two years, since survival rate is lower for patients treated with drugs and they also need to stay longer in hospitals to recuperate.

Primary angioplasty involves a balloon that is inserted into an artery and inflated.