Stents open era in heart surgery

Clem Reeve likes the idea that the tiny scaffolding placed in his heart will melt away once its vital job is done.

He began suffering chest pains in December. But now he is feeling even better than before, after becoming one of the first patients in a new international trial of dissolving heart stents.

"It's bloody brilliant. The best fact is that I'm getting a really good night's sleep," said 58-year-old Mr Reeve, a council roading assets manager, from Whangarata, south of Auckland.

The clinical trial is the second involving the Abbott stent, which is made of polylactic acid and breaks down within two years into carbon dioxide and water, to be absorbed into the walls of heart arteries.

It has been developed to replace stents made from metal. A stent is a tiny, expandable, mesh frame used to prop open a diseased, narrowed heart artery. A treatment for some heart attacks and angina, they improve the flow of blood and oxygen to the heart muscle.

The artery wall, thickened by fatty deposits, is pressed back by inflating a tiny balloon, then the stent is expanded into position, again by balloon. All this is done by remote control using a thin tube and wire inserted, under local anaesthetic, into a blood vessel at the groin and gently pushed up to the heart.

But after the risk of scar tissue growing back through the stent became clear, manufacturers added a coating to stents of a drug to inhibit this. Another problem is a small increase in the risk of blood clots forming at the stent, even years after they have been placed.

Around 6500 New Zealand patients a year are given heart artery stents; just over half are the drug-releasing kind.

Cardiologist Dr John Ormiston - who is on Abbott's advisory board, led the first trial and treated Mr Reeve at Auckland City Hospital - said a strong reason for the dissolving stent, which also releases the drug to prevent renarrowing, was that it might avoid the increased risk of late clots.

He points to results of the first trial of 30 straightforward patients, published in British medical journal The Lancet in March, which showed a low rate of major heart complications - one suffered a minor heart attack - and the stents were effective and had been absorbed within two years. The treated arteries were as flexible as those that had never had a stent.

A commentary in the journal by two experts in Italy says the dissolving stents may be a "major step" in heart treatment, but larger trials in more-complex patients are needed before they could be called a breakthrough.

The world's first patient to receive one, John Lamb, of Tauranga, is still feeling great following the treatment in 2006.