Heart stents for stable angina show no benefit over placebo, study findsBMJ 2017; 359 doi: https://doi.org/10.1136/bmj.j5076 (Published 02 November 2017) Cite this as: BMJ 2017;359:j5076
Percutaneous coronary intervention (PCI) is not significantly better than a placebo procedure in improving exercise capacity or symptoms even in patients with severe coronary stenosis, research has found.
The ORBITA study, published in the Lancet,1 is the first double blind randomised controlled trial to directly compare stenting with placebo in patients with stable angina who are receiving high quality drug treatment.
Coronary artery stents are life saving in patients with myocardial infarction. For patients with stable coronary artery disease who get pain only on exertion, guidelines recommend antianginal medicine as first line therapy, and PCI is reserved for the many patients who remain symptomatic.
A common perception is that PCI unquestionably improves angina, but no placebo controlled data support this. Cardiologists have so far resisted the idea of a placebo controlled trial of angina relief, partly because exposing patients to an invasive placebo procedure was feared to be unethical.
Unblinded trials of PCI have reported an increase in exercise time by 96 seconds more than medical therapy. Single antianginal drugs typically increase exercise time by more than 45 seconds when compared with placebo.
Researchers recruited 200 patients with severe (≥70%) single vessel stenosis from five study sites in the UK. Once enrolled, the patients had a six week phase of intensive medical treatment in which antianginal agents were introduced and increased to maximal doses. The patients were then randomly assigned to PCI (105 patients) or a placebo group (95 patients), in which they had an angiogram procedure but did not receive the stent. For the next six weeks neither the patients nor the doctors knew which procedure the patient had received.
Exercise tests were carried out before the procedure and six weeks afterwards. The average increase in overall exercise time was 28.4 seconds in patients who had PCI and 11.8 seconds in those who had the placebo procedure. However, this difference was not statistically significant (difference 16.6 seconds (95% confidence interval –8.9 to +42.0); P=0.200). And no significant differences were seen in patient reported improvement of symptoms in either group.
However, the tests did confirm that stenting considerably relieved narrowing in the coronary artery and improved blood supply to the heart.
Rasha Al-Lamee, of the National Heart and Lung Institute at Imperial College London and lead author of the study, said, “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.”
She added, “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 [instead of] taking long term medication to control their symptoms.”
The researchers noted that patients took high doses of medicine before the procedure: an average of three antianginal agents, which may not be adhered to in a real world setting. They added that participants all had the single vessel form of coronary artery disease and that patients with the multi-vessel form may get more symptom relief from stenting.
“It seems that the link between opening a narrowing coronary artery and improving symptoms is not as simple as everyone had hoped,” said Al-Lamee.