The PLATFORM (Prospective longitudinal trial of FFRCT: Outcome and resource impacts) study, which was presented at the 2015 European Society of Cardiology (ESC) meeting yesterday (1 September) and published in the European Heart Journal, indicates that use of fractional flow reserve computed tomography (FFRCT) is associated with a significant reduction in the number of invasive tests that do not find evidence of obstructive coronary disease.
Pamela S Douglas (Duke Clinical Research Institute, Durham, USA) and others report in the European Heart Journal that FFRCT (HeartFlow) is designed to determine the haemodynamic significance of coronary stenoses by computing FFR values using CT angiography data “based on computational fluid dynamics and simulated maximal coronary hyperaemia”. They add that the hypothesis of PLATFORM is that “patients with suspected coronary artery disease evaluated using a CT angiography/FFRCT-guided strategy would have fewer invasive angiograms that showed no obstructive coronary artery disease than would patients who were evaluated based on standard practice and would have similar and low rates of major cardiac events.”
In the prospective study, 584 patients without known coronary artery disease but with an intermediate likelihood of obstructive disease were assigned to usual diagnostic care or to FFRCT. Patients were then further grouped, based on a pre-enrolment evaluation, into those in whom an invasive test had been planned and into those in whom a non-invasive test had been planned. The primary endpoint was the rate of invasive coronary angiography within 90 days that did not show obstructive coronary artery disease among the group of patients for whom an invasive test had originally been planned (187 in the usual care group and 193 in the FFRCT group).
At 90 days, in the planned invasive testing group, the rate of the primary endpoint was 73.7% in the usual care group vs 31.6% in the FFRCT group. In the overall cohort, these figures were 73.3% and 12.4% respectively (p<0.001). Douglas et al note: “Propensity score matching resulted in inclusion of 148 patients in each group and yielded similar results (72% usual care vs. 12% CT angiography/FFRCT; p<0.0001).”
The authors comment that among patients assigned to FFRCT in the planned invasive coronary angiography group, two had a major adverse cardiac event—one, whose CT angiography was of insufficient quality for FFRCT analysis, had a peri-procedural myocardial infarction and one had to undergo urgent revascularisation after FFRCT analysis showed severe coronary artery disease. “There were no events in the 61% of CT angiography/ FFRCT patients in whom invasive coronary angiography was cancelled,” Douglas et al write.
Douglas says: “The study demonstrated that by using FFRCT, physicians were able to efficiently triage patients to the most appropriate care and dramatically reduce the use of invasive testing, which comes with greater risk and higher costs. While FFRCT is a relatively new technology, this study shows that physicians and patients being evaluated for stable chest pain should consider including this new test in the course of standard diagnostics.”
One-year follow-up data is ongoing and economic and quality of life data from PLATFORM is due to be presented as a late-breaking trial at TCT.