SAN FRANCISCO — Using CT to estimate fractional flow reserve in evaluating patients who are stable but show signs of CAD could improve resource use and patient quality of life, according to data presented at the annual TCT Scientific Symposium.
“There are many choices for evaluating patients who have stable, new-onset chest pain, so we’re not certain which is the optimal approach,” Mark A. Hlatky, MD, of the department of health research and policy, department of medicine, Stanford University School of Medicine, said during a presentation.
Mark A. Hlatky
In the PLATFORM study, the use of FFR-CT reduced the rate of invasive angiography without obstructive CAD from 73% to 12%, according to Hlatky said. “[Our] aim was to evaluate the economic and quality-of-life outcomes within PLATFORM,” he said.
Hlatky and colleagues stratified 584 symptomatic patients (75% with atypical angina) without known CAD based on planned invasive or noninvasive diagnostic testing, then assessed consecutive observational cohorts with usual care or FFR-CT. The probability of CAD among patients before testing was 49%.
At 90 days, the investigators multiplied the number of diagnostic tests, invasive procedures, hospitalizations and medications by U.S. cost weights and tallied them to calculate total medical costs. The researchers assessed changes in quality of life from baseline to follow-up using the Seattle Angina Questionnaire, the EuroQOL and a visual analog scale.
“[Because] no Medicare assessment has yet been set for FFR-CT, in our primary analysis we used $0 as a cost weight to estimate the cost offsets,” Hlatky said. “In a sensitivity analysis, we used multiples of the CTA cost weight to estimate the costs.”
In the planned invasive stratum, mean costs were 32% lower among patients with FFR-CT compared with usual care ($7,343 vs. $10,734; P < .0001). In the planned noninvasive stratum, no significant differences were observed between the FFR-CT group and the usual care group ($2,679 vs. $2,137; P = .26).
In a sensitivity analysis with cost weight of FFR-CT set to seven times that of CTA, the FFR-CT group still showed lower costs vs. usual care in the invasive stratum ($8,619 vs. $ 10,734; P < .0001). When the FFR-CT cost weight was set to half that of CTA, the costs were higher with FFR-CT than the usual care group ($2,766 vs. $2,137, P = .02) in the noninvasive stratum.
In the overall study population, each quality-of-life score improved (P < .0001). Quality-of-life scores improved more with FFRCT than usual care in the noninvasive stratum (Seattle Angina Questionnaire: 19.5 vs. 11.4; P = .003; EuroQOL: 0.08 vs. 0.03; P = .002; and visual analog scale: 4.1 vs. 2.3; P = .82); the improvements were similar in the FFR-CT and usual care groups in the invasive stratum.
“In symptomatic patients with an intermediate probability of [CAD], an evaluation strategy based on FFR-CT had lower costs than a basic coronary angiography and greater improvement in quality of life than usual care noninvasive testing,” Hlatky said. – by Allegra Tiver
Hlatky MA, et al. PLATFORM: Quality-of-life and economic outcomes of an FFR-CT diagnostic strategy in patients with suspected coronary artery disease. Presented at: TCT Scientific Symposium; Oct. 11-15, 2015; San Francisco.
Disclosure: Hlatky reports receiving research grants from HeartFlow.