The drug - a slimmed-down form of the commonly used clot-dissolving drug heparin - could be used as a do-it-yourself home injection kit for heart attack or chest pain victims.

Enoxaprin works by helping to stifle a clot-forming protein that enters the bloodstream after the heart is damaged, its developers say.

The release of clot-inducing proteins into the bloodstream continues months after chest pain or mild heart attacks.

But researchers, writing in Circulation, the journal of the American Heart Association, claim it should be possible to develop enoxaparin injections for use by patients at home.

Effective therapy

Lead researcher Dr Elliott Antman, director of a Boston-based cardiac unit, said: "It seems logical to not only provide effective anti-clotting therapy during the initial episode of chest pain or just after the heart attack, but to also use that therapy in the months following that event.

"In theory, this new research might allow physicians to prescribe relatively unsupervised long-term self-administration of anti-clotting therapy, sort of an insulin-like injection for coronary artery disease."

Drug could combat health problems

By using enoxaparin, researchers were able to control von Willebrand factor, a protein released into the bloodstream when blood vessels are inflamed or when a person has a heart attack or chest pain.

Enoxaparin 'superior'

The scientists found enoxaparin to be superior to heparin in controlling von Willebrand factor.

When released into the bloodstream, von Willebrand factor directs platelets - disk-shaped blood particles that help form clots - to the damaged area of blood vessels, leading to a particle pile-up that can form blood clots. By suppressing von Willebrand factor, potential clots can be avoided.

Scientists found high blood levels of von Willebrand factor were a sign of future heart attacks or chest pain.

Dramatic increase

The levels of von Willebrand factor increased dramatically over the first 48 hours following a heart attack or an episode of chest pain in those people treated with regular heparin. The release of this factor was lessened in people receiving enoxaparin.

In a follow-up 14 days after people had an episode of chest pain or a mild heart attack, nine of the 34 people treated with enoxaparin had another bout of chest pain or a heart attack compared to 17 of 34 people given regular heparin.