Info Gleaned From FFRCT Has Durable Impact on 1-Year Outcomes: ADVANCE Registry
“Adding physiology to the anatomy is going to be an approach that we’re predominately using in the future,” Matthew Budoff says.
NEW ORLEANS, LA—Patients with suspected CAD whose management is informed by CT-derived fractional flow reserve (FFRCT) experience low event rates through 1 year, new findings from the ADVANCE registry show. The test seems to effectively risk-stratify patients: normal baseline values were linked to less revascularization as well as a lower risk of CV death or MI over time.
The long-term results are good news, in that they extend the 90-day data showing similar patterns.
“The ADVANCE Registry shows the use of FFRCT as a complement to CTA in current real-world clinical practice is occurring and can be informative,” Manesh Patel, MD (Duke University Medical Center, Durham, NC), said yesterday in a featured clinical research session at the American College of Cardiology (ACC) 2019 Scientific Session. The latest findings were simultaneously published online in JACC: Cardiovascular Imaging.
Currently, he noted, the evaluation of suspected CAD is quite varied and relies on pretest likelihood of disease, ability to exercise, other test results, and—perhaps most importantly—"the ability to discriminate downstream risk. It’s that risks that we’re often in the clinics trying to identify for our patients as we decide which way to care for them.”
Coronary CT angiography (CTA) is increasingly being used as the primary diagnostic tool in these patients, Patel noted. While it has high sensitivity, however, it has modest specificity and is “associated with high rates of follow-on invasive coronary angiography, some of [which] show nonobstructive coronary disease, and leads to increased rates of revascularization,” he said, adding that CTA is also unable to provide functional information.
Therein lies the appeal of FFRCT, according to Patel: the ability to gauge both function on top of the anatomical information provided by CTA. The goal of ADVANCE, he said, was to see how these imaging modalities were being used in real-world practice.
As reported by TCTMD last fall, ADVANCE tracked treatment plans and outcomes for 5,083 patients with clinically suspected CAD and ≥ 30% degree stenosis on coronary CT angiography (CTA) who were enrolled at 38 sites in Europe, North America, and Japan between July 15, 2015, and October 20, 2017. More than half of the cohort (58%) presented predominately with angina.
Site investigators first described their management plan and treatment strategy based on CTA alone. Then, at physician discretion, patients with stenoses in the range of 30% to 90% on CTA could be evaluated using FFRCT (HeartFlow), after which investigators were given the option of rethinking their plan. Nearly two-thirds of the time (63.5%) they did so. For the primary endpoint, reclassification between a core lab-determined strategy based on CTA alone versus CTA plus FFRCT, the rate was 66.9%.
The 90-day findings indicate “we’re safely deferring individuals who might have gone ahead and had maybe an inappropriate and invasive angiography,” investigator Timothy A. Fairbairn, MBChB, PhD (Liverpool Heart and Chest Hospital, England), told TCTMD at the time. “So the test is being used in a sensible, practical manner, and it does really seem to be benefiting . . . in terms of moving patients in the right direction.”
The Long View
Here at ACC, Patel shared results showing this continues to be the case. One-year data were available for 4,288 patients (93% of the original cohort).
By 1 year, revascularization was nearly seven times more common in patients with FFRCT values of 0.80 or below than in those above that cut point, at 38.4% vs 4.6% (RR 6.87; 95% CI 5.59-8.45). Most of the procedures occurred within the first 90 days.
Among these patients in whom medical therapy was recommended based on FFRCT, 92.9% continued with this strategy through 1 year and 7.1% underwent PCI or CABG.
There were a total of 55 MACE when evaluated as time-to-first event: 35 deaths (of which 15 were CV-related), 12 MIs, and eight ACS with unplanned hospitalization leading to revascularization.
Neither MACE nor the combined rate of all-cause death and MI significantly differed by baseline FFRCT. Looking specifically at the 1-year rate of time to first CV death/MI, though, outcomes were worse for the FFRCT ≤ 0.80 group than for the FFRCT > 0.80 group (0.8% vs 0.2%; RR 4.22; 95% CI 1.28-13.95).
MACE rates increased in a stepwise fashion as FFRCT values decreased, Patel reported.
That MACE were so infrequent in patients undergoing CTA “highlights the need for ongoing efforts to refine the pretest evaluation and risk assessment in clinical practice, which is the focus of an ongoing randomized trial known as PRECISE,” he added.
Patel concluded: “Lower rates of revascularization and clinical events in patients with FFRCT > 0.80 who were managed conservatively provide reassurance regarding this clinical strategy.”
Panelist Matthew Budoff, MD (Harbor-UCLA Medical Center, Torrance, CA), said the idea of “adding physiology to the anatomy is going to be an approach that we’re predominately using in the future.” An FFR-like approach will likely prove to be as important with CTA has it has in conjunction with invasive, catheter-based angiography, he predicted. “Obviously, the PRECISE trial will hopefully frame that a little bit better.”
One interesting aspect of the current data, Budoff pointed out, is that there was no “inflection point” around the 0.76 to 0.80 range, thought by some to be an area of “diagnostic accuracy loss” where FFR values might be less informative. Yet here, outcomes rose gradually and there was no abrupt cutoff, he explained. “I think that’s reassuring that this tool is performing the way that you’d expect it to—as FFRCT drops, at least on a per-patient basis, the event rates go up.”
Budoff asked what is known about the cost of the testing strategy. In reply, Patel explained that cost data from an international registry are difficult to interpret—ADVANCE spanned across sites in Europe, North America, and Japan.
Commenting on the results for TCTMD, Subha Raman, MD (Ohio State University Wexner Medical Center, Columbus), said that she's glad long-term data have come out. As for what should come next, she added, “Prospective evaluation of how this technology performs in a Kaiser-like health system would be a great addition to the field.”
Patel reports receiving research grants from HeartFlow, Bayer, Janssen, Phillips, Medtronic, AstraZeneca, and the National Institutes of Health as well as serving on the advisory boards of Bayer, Janssen, and Amgen.
Raman reports no relevant conflicts of interest.