Study finds lack of evidence for effectiveness of heart stents

The Irish Heart Foundation has played down the findings of a recent study that found a lack of evidence for the effectiveness of heart stents in relieving chest pain.

The research, published this week in the Lancet medical journal, studied 200 patients who had a blocked coronary artery and were experiencing chest pain.

During the study, carried out by Imperial College London cardiologist Dr Justin E Davies and his colleagues, a stent was inserted into half of the patients and a placebo operation, without inserting a stent, was performed on the other patients.

For six weeks, all the patients were treated with a blood pressure drug and medication to reduce their risk of a heart attack before the procedure.

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Following the procedure, both groups of patients then took powerful drugs to prevent blood clots.

Researchers then tested patients with a series of physical exercises, and found the subjects who received the stents did not feel any different to those who had not. There was also no difference between the two groups physical performance.

A stent is a small tube used to open up arteries in patients experiencing heart attacks, or chest pain due to blocked arteries.

‘No evidence’

The study concluded there was “no evidence” from the trials to show stents were effective in reducing chest pain for patients with blocked arteries. Both sets of patients taking part in the study felt less chest pain at the end of the six weeks.

Dr Angie Brown, medical director of the Irish Heart Foundation, played down the significance of the study.

“We already know that medical treatment is very successful in treating chest pain and reducing future coronary events and that stenting treats only a section of a diseased vessel,” she said.

“So though it is surprising, no difference was found in the two patient groups, this study confirms how good medical therapy is. It’s also important that the patients in the study are followed up for longer than six weeks to ensure this remains the case over time.”

Dr Brown, a cardiologist, said stenting remains a “crucial treatment”, particularly among patients intolerant to medication or medical therapy.

Figures from the Irish Heart Foundation show about 10,000 people in Ireland die each year from heart disease or related cardiovascular issues. The main cause of heart disease is the buildup of fatty deposits on the inner lining of blood vessels.

Risk factors

Common risk factors that are known to increase the likelihood of heart disease include smoking, high blood pressure or cholesterol, stress, obesity and an unhealthy diet.

Dr David Maron, a cardiologist at Stanford University, praised the new study as "very well conducted" but said it left some questions unanswered. The participants had a profound blockage but only in one artery, and they were assessed after just six weeks, he said.

“We don’t know if the conclusions apply to people with more severe disease,” Dr Maron said. “And we don’t know if the conclusions apply for a longer period of observation.”

Cardiologists said one reason for the results of the study might be that atherosclerosis (the blocking of the arteries) affects many blood vessels, and stenting only the largest blockage may not make much difference in a patient's discomfort. Additional reporting – New York Times