It may be a waste of time to undergo a heart procedure for angina, a study suggests.
Around two million people in the UK and 10 million in the US have angina, which causes chest pain following physical activity because of restricted blood flow to the heart. Many have a small metal tube called a stent put in to widen their arteries.
But the procedure, which can damage the arteries or cause excessive bleeding, has been found to have no significant benefit for patients’ symptoms or quality of life.
Researchers from Imperial College London looked at 200 patients who either received a heart stent or a sham procedure.
A study by Imperial College London found the operation has a huge risk of damaging the arteries but does not improve quality of life
Doctors widely believe the stent ‘unquestionably improves angina’, according to the researchers. But when the effect on patients’ ability to exercise was examined, the stent group showed little difference.
Lead author Dr Rasha Al-Lamee, from Imperial’s National Heart and Lung Institute, said: ‘It seems that the link between opening a narrowing coronary artery and improving symptoms is not as simple as everyone had hoped.’
She added: ‘Surprisingly, even though the stents improved blood supply, they didn’t provide more relief of symptoms compared to drug treatments – at least in this patient group.’
The results add to growing evidence that procedures including keyhole knee surgery and arthritis operations do not work in themselves but only because of a ‘placebo effect’.
In Britain, more than 94,000 people a year receive a Percutaneous Coronary Intervention (PCI) to put a stent into their artery. It is done for people who have had a heart attack, as well as the nearly one in seven men and one in 12 women with angina because of hardened arteries or fatty plaques in their blood vessels.
The study of 200 patients in London and the south of England measured the effect of a stent on how long people could exercise after the procedure before needing to stop.
They found the average increase in overall exercise time was 28·4 seconds for patients who had the PCI procedure.
Those given a sham version of the procedure, getting an angiogram using a catheter to examine their arteries but no stent, managed 11.8 seconds. The authors say this is not ‘statistically significant’ so could be due to the stent or to chance.
Importantly those given a stent and the group denied it reported no significant difference in their symptoms, despite stents being shown to improve blood supply to the heart.
The study, published in the Lancet, said any benefits from the procedure may therefore be down to the placebo effect – where something works simply because patients and cardiologists believe it will.
Dr Al-Lamee, who is also an interventional cardiologist at Imperial College Healthcare NHS Trust, said: ‘While these findings are interesting and deserve more attention, they do not mean that patients should never undergo the procedure for stable angina.
‘It may be that some patients opt to have an invasive procedure over taking long-term medication to control their symptoms.’
The patients in the study all had stable angina, which is reliably triggered by exercise or stress. Many patients manage the condition with drugs such as beta-blockers or nitro-glycerine, which were also used during the six-week trial.