PARIS – Pressure wire assessment of ischemia in patients with stable angina changed the management strategy for these patients 27% of the time compared with decisions based solely on coronary anatomy information from angiography, in a prospective, multicenter British study with 200 patients.
Basing management of patients with stable angina on an angiogram alone is a "flawed" strategy, Dr. Nick Curzen said at the annual congress of the European Association of Percutaneous Cardiovascular Intervention. "Management of patients would be improved by routine use of fractional flow reserve [FFR] assessment at the diagnostic stage," he said.
Dr. Curzen stressed that this was a pilot study, and said that he is now trying to gather the funding needed to start a large-scale randomized trial to compare management decisions made with angiography alone with those made by routine ischemia assessment using a pressure wire to measure FFR throughout the main coronary branches of patients with stable angina suspected to be of coronary origin. Another limitation of the current results is "we have no idea whether this approach will be cost effective," he said.
Although results from three prior studies – DEFER (J. Am Coll. Cardiol. 2007;49:2105-11), FAME (N. Engl. J. Med. 2009;360:213-24), and FAME 2 (N. Engl. J. Med. 2012;367:991-1001) – together established definitively that measuring FFR with a pressure wire benefited patients by allowing interventionalists to identify clinically important coronary stenoses during percutaneous coronary intervention (PCI), the new study moved the time of pressure wire use earlier in the course of patient management.
"We pushed the time for FFR back to the diagnostic stage, not during PCI itself," said Dr. Curzen, professor of interventional cardiology at the University Hospital in Southampton (England)."The limitation of prior studies is that they did not take into account the options of medical management or coronary artery bypass grafting."
"This is a very, very important study. So far, measurement of fractional flow reserve has only been in patients already committed to undergoing PCI. But these data suggest that adding a pressure wire assessment at the diagnostic stage is potentially disruptive for current practice, it could potentially be very important for allocating resources, it may reduce the need for noninvasive testing, and it may also improve outcomes. I’m a big believer in the importance of ischemia," commented Dr. William Wijns, codirector of the cardiovascular center at OLV Hospital in Aalst, Belgium.
"We now need results from a prospective study to establish a link between this approach and improved outcomes," Dr. Wijns added.
The RIPCORD (Does Routine Pressure Wire Assessment Influence Management Strategy at Coronary Angiography for Diagnosis of Chest Pain?) study enrolled 200 stable angina patients at 10 British centers. All patients underwent diagnostic angiography, and then the cardiologists recorded their treatment recommendation based on the anatomic information only, choosing among medical treatment, PCI, coronary bypass surgery, or need for additional, noninvasive testing, usually an exercise stress test. While the patients remained in the catheterization laboratory, they underwent pressure wire assessment for ischemia. Those findings were presented to the cardiologist, who could then change the initially recommended treatment if necessary based on this additional information.
Taking the FFR information into account changed recommended management for 53 of the 200 patients (27%). The changes led to more aggressive management in some patients and less aggressive treatments for others. For example, among the 90 patients initially flagged for PCI on the basis of their coronary anatomy, the attending cardiologists changed their recommendations to medical management for 24 patients after they found that none of the coronary lesions in these 24 patients caused clinically significant ischemia. On the other hand, among the 72 patients initially slotted for medical management based on their angiogram, the cardiologists found 9 patients whom they realized needed revascularization with PCI (6 patients) or coronary surgery (3 patients), Dr. Curzen reported.
Another result from the FFR assessment was a sharp drop in the number of patients with ambiguous results who required further testing. The number of cases that the cardiologists felt needed further testing dropped from 15 after angiography alone to a single patient once the FFR results were also available.
The study’s secondary endpoint was the change in the number of coronaries identified within each patient with significant stenoses that required treatment. Adding in the FFR information changed this designation for 64 of the 200 patients (32%). For example, angiography identified 84 patients with single-vessel disease, but with the pressure wire results, 24 of these patients were downgraded to having no affected coronary arteries, 6 patients got upgraded to having two-vessel disease, and an additional patient was identified with significant left-main disease that had been missed by angiography.