Researchers from the Golden Jubilee National Hospital and the University of Glasgow have reported a study that shows one in ten patients may not need cardiac intervention following a heart attack and in those that do need stents, the procedure can be targeted more effectively.
The FAMOUS-NSTEMI trial examined the potential benefits of routinely using a wire guided procedure that can accurately measure blood pressure through a narrowed heart artery, Fractional Flow Reserve (FFR), to determine what treatment a patient should receive following a non-ST segment elevation myocardial infarction (NSTEMI), the most common type of heart attack.
Traditionally, following an NSTEMI, patients would receive coronary arteriography: having a dye injected into the heart arteries to reveal any narrowing or complications on an x-ray. In an attempt to reduce subjective interpretation of these images and uncertainty about treatment, the FAMOUS-NSTEMI trial, proposed that all patients should routinely undergo FFR. The FFR method involves measuring the 'pressure-drop' across a coronary narrowing and using the index of pressure loss as a measure of the severity of the narrowing and in turn, whether the patient should be treated with medical therapy, stents, or bypass surgery.
The trial, led by the Golden Jubilee National Hospital and the University of Glasgow, funded by the British Heart Foundation (BHF) and supported by St Jude Medical, showed that 22.7% of the 176 patients who were randomly assigned to FFR-guided therapy trial did not require revascularisation (stents or bypass surgery) and were able to have their condition managed medically, compared to 13.2% of 174 patients assigned to the standard care group Overall, in the FFR-guided group, a change in the initial treatment plan for bypass surgery, stents or tablets only, occurred in one the fifth of patients.
Discussing the investigation, Professor Colin Berry, Consultant Cardiologist at the Golden Jubilee National Hospital, Professor of Cardiology and Imaging at the University of Glasgow and the Principal Investigator on the study, said:
Generally, patients that are referred for treatment following an NSTEMI are expected to receive a stent or sometimes bypass procedure. This decision is made based on all of the available clinical information and especially the images taken from x-rays of the affected heart arteries.
Measuring FFR, however, allows us to more accurately assess the severity of a heart artery narrowing, to inform the decision for medication only, stents or bypass surgery. The FFR result potentially provides more objective information than subjective visual assessment of heart artery narrowing’s by the doctor. Potentially, FFR safely reduces the number of individuals requiring stents or surgery, and importantly, leads to an optimised, safer stent procedure when it is performed.
The study took place in six hospitals across the UK. Patients were randomly assigned to FFR-guided management or usual care (FFR measured but not disclosed to the doctors) and so the participating patients were split into two groups; all participants would have their FFR levels monitored, however, only half of these individual’s doctors were shown the results.
Professor Peter Weissberg, Medical Director at the BHF, which funded the clinical trial, said:
Someone has a heart attack in the UK every three minutes, meaning research to enhance diagnosis and treatment is crucial. These promising findings show a possible way to improve how cardiologists decide how to treat people who have had an NSTEMI heart attack, where the blood supply to the heart is only partially blocked.
This test might stop patients being given stents unnecessarily, which could also reduce the cost of care. A much bigger study is now needed to be certain that measuring blood flow in this way will lead to better outcomes for patients and save money for the NHS.
Professor Berry added: “This trial was a ‘proof-of-concept’ clinical study in heart attack patients and we are excited about the results. Some of the these are very clear, including the safety and feasibility of FFR guided treatment initially, and the improved safety of stent procedures. FFR is an established technology in stable patients, but this is not the case in heart attack patients. As such, more research is needed to assess whether this new approach can make a positive difference to the lives of patients.”