Some patients experiencing chest pain from reduced blood flow to the heart, known as angina, may benefit from having a stent implanted instead of starting chest pain medication, according to researchers at Imperial College London and Imperial College Healthcare NHS Trust. The research was partially funded by the NIHR, including the NIHR Imperial BRC Cardiovascular Theme Co-Lead Dr Rasha Al-Lamee.
The team found that implanting a stent – a tiny device that helps keep a narrowed artery open – in the heart improved chest pain and the patient’s ability to do exercise compared to patients who had not received a stent but had undergone a placebo procedure instead.
The ORBITA-2 trial follows the 2017 ORBITA trial, which found stents had no significant additional benefit on exercise capacity, symptoms or quality of life compared to medication. Participants in the ORBITA trial received stents (or placebo procedure) according to the current guidelines for treating patients with angina, which state patients should be offered three different types of chest pain medication to treat angina before a stent is considered.
Researchers suspected the lack of benefit from stents shown in the previous ORBITA trial may have been due to the high levels of chest pain medication these patients were taking, meaning stents did not have additional benefit.
To explore this further, patients in the ORBITA-2 study stopped taking their chest pain medication before receiving a stent or placebo procedure. Patients continued taking other medications, including aspirin and statins that reduce the risk of heart attack.
Analysis showed that more than one-third of patients who received a stent in the ORBITA-2 trial were free of angina symptoms at the end of the trial. These patients were three times more likely to have no angina at the end of the study than patients who received the placebo procedure. Stenting was not effective for all patients and 59 per cent of those who received a stent during the study continued to experience chest pain even after a successful procedure.
Dr Al-Lamee, who led the trial at Imperial College London and is also an interventional cardiologist at Imperial College Healthcare NHS Trust said: “The reality of clinical practice tells us that trying multiple chest pain medications is not realistic for patients who are experiencing uncomfortable angina symptoms. In the future, patients and medical teams have a choice of two pathways. For chest pain relief: anti-anginal chest pain medication or implanting a stent. All patients will need to continue medications that reduce their risk of future events such as heart attacks and death.”
“The key finding from looking at our two trials together is that the first treatment offered seems to have the maximum effect. Stents are not risk or cost-free but their use as an upfront procedure can now be considered evidence-based and potentially effective for some patients.”
“The ORBITA and ORBITA-2 trials suggest the American and European guidelines for stable coronary artery disease may require updating to offer more flexibility for patients and clinicians to decide which treatment is most appropriate. Our study suggests that by restricting stenting to patients with inadequate response to chest pain medications, we may inadvertently be selecting the group of patients with the least to gain.”
Results of the trial were presented by Dr Christopher Rajkumar, a clinical research fellow at Imperial College London and lead author of the study, at the American Heart Association’s Scientific Sessions 2023 and published at the same time in the New England Journal of Medicine.
Researchers found that the positive effect of stenting was immediate and continued throughout the 12-week follow-up. They asked patients to score their symptoms daily using a specially developed app and found scores improved at the end of the study in those patients who had received a stent. These patients could also exercise for around one minute longer than those who received the placebo procedure. This is noted to be a smaller effect than many cardiologists would have believed from existing data and thought to be similar to the effect of one full dose of chest pain medication.
The study recruited 301 patients across 14 sites in the UK. Participants and research teams were unaware if they had received a stent or placebo procedure during the trial. Patients had 24-hour access to clinical research teams who were also unaware if patients had received a stent or not and medication was restarted if any participants complained of symptoms. Four patients in the stenting group and six in the placebo group experienced a heart attack.