When PCI Decisions Ignore FFR Results, Patients Pay a Price

When the choice about whether to perform PCI diverges from fractional flow reserve (FFR) results—not unusual in real-world practice—patients can suffer worse outcomes, suggest Canadian registry data.

PCI in nonischemic lesions carried greater 5-year MACE risk, as did medical therapy in ischemic lesions with an FFR value of 0.80 or below. The results were presented as an abstract during the virtual American Heart Association 2020 Scientific Sessions and published online in JAMA.

Both US and European guidelines emphasize that FFR should play a role in guiding revascularization decisions related to angiographically intermediate stenoses. Senior author Dennis T. Ko, MD (ICES, Toronto, Canada), told TCTMD that his group had wanted to see how closely clinicians were following this advice and to what benefit.

“Obviously FFR has increased in use in many countries and it’s common in interventional practice, [but] there is variation in use of the technology. I think some places use a lot more and some places use a lot less,” said Ko. Most studies thus far have been either randomized trials or observational studies conducted at highly experienced cath labs, he pointed out. “We know that technology when it’s used in the real world isn’t really as good as the randomized trial setting.”

Here, Ko noted, data were captured as part of routine care. “We saw some overutilization. We saw some underutilization. So I think it’s a good lesson that there’s definitely room for improvement in clinical practice,” he said, cautioning that the study is observational.

Still, the signal of harm in patients who undergo intervention despite their negative FFRs is noteworthy, Ko said. “We originally thought that doing angioplasty in these patients, probably it’s ok, no harm done and such. And it turned out that that’s actually not the case.”

We saw some overutilization. We saw some underutilization. Dennis Ko

Ko, along with lead author Maneesh Sud, MD (ICES) and colleagues, retrospectively analyzed data on 9,106 patients (mean age 65 years; 35.3% women) who underwent single-vessel FFR assessment from April 2013 to March 2018 in Ontario, Canada. Presentations included stable CAD (about 62%) as well as unstable angina and NSTEMI, whereas patients with left main disease or STEMI were excluded. Outcomes were tracked through March 2019.

Overall, 30% of patients had an ischemic FFR value of ≤ 0.80 and 70% had a nonischemic value above that cutoff.

In the ischemic group, 75% of individuals underwent PCI and 25% received medical therapy despite their positive FFR. PCI reduced the primary endpoint of 5-year MACE, defined as the composite of death, MI, unstable angina, or urgent coronary revascularization compared with no PCI (31.5% vs 39.1%; HR 0.77; 95%CI 0.63-0.94).

By comparison, 87.4% of patients in the nonischemic group received medical therapy and 12.6%, despite their negative FFR values, underwent PCI. Here, intervention was associated with increased 5-year MACE compared with no PCI (33.3% vs 24.4%; HR 1.37; 95% CI 1.14-1.65).

‘Added Value’

Richard G. Bach, MD (Washington University School of Medicine in St Louis, MO), writing in an accompanying editorial, agrees that despite the study’s limitations—among them its restriction to relatively straightforward single-vessel FFR assessment and observational design—the results validate the “added value” of physiologic testing.

“Failure to incorporate such physiologic assessment into the routine practice of diagnostic cardiac catheterization and clinical decision-making for managing coronary artery disease represents a missed opportunity to provide better outcomes for patients with coronary artery disease,” he stresses.

But as he and the researchers both note, an unknown here is why operators chose not to heed the FFR values. As Bach observes: “Physiologic testing by FFR is only one variable in a complex multifaceted decision process for or against revascularization of any given lesion; there are many valid reasons that such decisions may have been reasonable and justified.”

Potential factors why FFR hasn’t been universally embraced, he notes, are “misplaced confidence in visual estimation by angiography, costs, lack of familiarity or experience with the technology, confusion regarding the optimal thresholds for the definition of ischemia, and possibly uncertainty that the results of randomized clinical trials and their selected study populations can be generalized to routine practice.”

Speaking with TCTMD, Ko said that the disparities between FFR and revascularization are “something we need to look at and try to understand a bit more in the future.” Possibilities include patients being asymptomatic or having diffuse disease without focal stenosis, he added.

His theory, though, is that many cardiologists still place more stock in angiographic findings than they do in physiologic findings. He emphasized that the latter provides a more objective cutoff but acknowledged that FFR won’t drive decisions 100% of the time. “Things can happen,” Ko observed, and patient preference also matters.