A commonly used test for diagnosis and treatment of angina is flawed in at least a quarter of cases when used on its own, a leading heart specialist claimed today.
The condition, which is characterised by a painful tightening of the chest when a build-up of fatty substances blocks or interrupts the blood supply to the heart, is diagnosed using coronary angiography.
These are X-rays taken via tubes which are put in the wrist or groin to inject dye into the coronary arteries to highlight narrowings. This is considered the “gold standard” method for diagnosing angina.
But Professor Nick Curzen, a consultant cardiologist at Southampton General Hospital, said angiograms would be more accurate if combined with a pressure wire to assess the severity of blockages at the diagnostic stage after 200 angina patients were examined in a study in 10 locations across the UK.
Used in conjunction with angiography, the additional test, known as fractional flow reserve (FFR), would allow doctors to choose the most appropriate management plan for their patients, which could be medical management, the insertion of a stent (angioplasty) or coronary artery bypass graft surgery.
The tiny wire, which is passed into individual major arteries to measure pressure within the vessel, gives a precise reading of whether blood flow is significantly restricted through the coronary artery, which is vital in deciding if the artery needs either a stent or surgery.
In the study, Prof Curzen found more than a quarter (26%) of stable heart disease patients would have had the wrong treatment plan based on angiogram alone.
The findings could be important because coronary artery disease is the most common cause of angina and heart attacks and responsible for 82,000 deaths in the UK every year.
As part of the project, cardiologists performed diagnostic angiograms on the patients with stable chest pain and drew up their treatment plans based on the initial assessment before leaving the room to allow a second cardiologist to carry out the pressure test.
Results were shared with each patient's original doctor - those who performed the initial angiograms - to give them an opportunity to see if the additional information would alter their decisions.
In 26% of the 200 cases, the management plan changed after the cardiologist had seen the FFR information and further analysis showed the pressure wire measurement changed cardiologists' opinion on whether individual coronary arteries had “significant” narrowings in almost a third of vessels (32%).
“Although this was a proof-of-concept study, the results indicate management of patients with stable angina by angiogram alone is probably flawed and treatment would be much more tailored to the individual through routine use of a FFR pressure test at the diagnostic stage,” said Prof Curzen.
“Not only did we see a quarter of treatment plans change, decisions on the significance of a patient's disease changed in a third of patients following the inclusion of FFR information, which suggests there is real need for the specialty to rethink the most effective universal approach.”
Prof Curzen said a large randomised trial comparing angiography and FFR-guided assessment and management of patients with stable angina was needed to provide comprehensive data on cost as well as clinical outcomes.
He added: “We are now working with collaborators to design such a trial and attract funding for it and, if this large scale study is positive, it could lead to a major change in practice in this area of medicine.”