Care guided by coronary computed tomographic angiography (CTA) and selective fractional flow reserve with CTA (FFRCT) was associated with equivalent clinical outcomes, quality of life, and lower costs in patients with stable chest pain and planned invasive coronary angiography, compared with usual care.
Pamela S. Douglas, MD, of the Duke Clinical Research Institute at Duke University School of Medicine in Durham, North Carolina, and colleagues compared 1-year clinical, economic, and quality of life outcomes in usual care and FFRCT. Their findings were recently published in the Journal of the American College of Cardiology.
“Evaluation of chest pain is a common clinical problem, yet disagreement remains regarding optimal evaluation strategy, in part because of the many available testing options,” researchers wrote. “The landmark PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) trial suggested that an evaluation strategy based on CTA was safe and clinically effective, but increased the rate of subsequent cardiac catheterization by almost 50% compared with functional testing.”
In the present study, named PLATFORM (Prospective Longitudinal Trial of FFRCT: Outcome and Resource Impacts), researchers enrolled symptomatic outpatients at least 18 years of age without known coronary artery disease (CAD) “who had an intermediate likelihood of obstructive CAD (20% to 80%) and whose physician had planned nonemergent CV testing to evaluate suspected CAD.”
A total of 584 patients were followed for 12 months: 204 patients In the planned noninvasive testing stratum (usual care noninvasive testing: n=100; CTA followed by selective FFRCT: n=104) and 380 patients in planned invasive testing stratum (usual care: n=187; CTA followed by selected FFRCT: n=193). Patients were 60.9 years on average (40% women), and some had diabetes, hypertension, a history of smoking, and/or dyslipidemia.
In the planned invasive testing stratum, CTA was performed in 100% of patients who received FFRCT-guided care, submitted for FFRCT in 69%, and analyzed in 60%. Of the 60% of patients who had planned invasive coronary angiography cancelled, researchers reported that the FFRCT data were considered in the treatment decision in 79%, with 55% of the decisions based solely on that data. Revascularization was performed in 28% of patients; 5% being coronary artery bypass grafting (CABG).
Catheterization without obstructive CAD at 90 days occurred in 12% FFRCT-guided care patients and in 73% of usual care patients, which yielded a risk difference of 61% (95% confidence interval [CI]: 53.0%–68.7%; P<.0001).
Only 2 MACE events occurred during the 1-year follow-up in the FFRCT-guided care group—1 periprocedural myocardial infarction (MI) and 1 hospitalization for urgent revascularization while awaiting CABG. “Importantly, there were no events during 1 year of follow-up in the 117 whose planned ICA [invasive coronary angiography] was cancelled on the basis of the CT/ FFRCT findings, only 4 of whom underwent ICA during 1-year follow-up,” the authors wrote.
In the usual care group, 2 MACE events occurred—1 unexplained death and 1 nonfatal MI during cardiac surgery—as well as 2 vascular complications at 1 year. “The risk difference between the groups was nearly zero,” Dr Douglas and colleagues noted. “However, there was insufficient evidence to conclude noninferiority due to low power.”
In addition, the cost of medical care was significantly lower in the FFRCT-guided strategy group vs the usual care strategy group (mean 1-year per-patient: $8127 vs $12 145; P<.0001; 95% CI on the $4018 difference: $1590–$6577).
Meanwhile, in the planned noninvasive testing stratum managed by FFRCT-guided care, CTA was also performed in 100% of patients, submitted for FFRCT in 64%, and analyzed in 58%. Catheterization without obstructive CAD at 90 days occurred in 12.5% of FFRCT-guided care patients and in 6.0% of usual care patients with a risk difference of –6.5 (95% CI: –14.4 to 1.4; P=.95). Only 1 MACE event occurred (a nonfatal MI) in the usual care planned noninvasive group compared to zero in the FFRCT-guided group during the 1-year follow-up.
A few minor limitations should be noted: small sample size, follow-up duration that may not be sufficient to detect an effect on clinical outcomes in this patient population (low-to-intermediate risk), and the lack of randomization.
To that end, the authors concluded, “Randomized trials are needed to compare the clinical utility of FFRCT with invasive strategies for evaluation of patients with suspected coronary disease.
Disclosures: The PLATFORM study was funded by HeartFlow (Redwood City, CA). Dr Douglas received grants from HeartFlow during the study and has previously received other support from GE Medical Systems. Other study authors also reported financial ties to the pharmaceutical industry.
Douglas PS, De Bruyne BD, Pontone G, et al; on behalf of the PLATFORM Investigators. 1-year outcomes of FFRCT -guided care in patients with suspected coronary disease. The PLATFORM Study. J Am Coll Cardiol. 2016;68(5):435-445. doi: 10.1016/j.jacc.2016.05.057.