Trials and guidelines support use of a pressure wire to measure the functional importance of angiographically questionable coronary lesions in stable patients, but a lot of operators apparently remain unconvinced of its value. Would real-world evidence for a survival benefit change their minds?
In a registry study, 1-year mortality fell a significant 43% with such fractional flow reserve (FFR) guidance of percutaneous coronary intervention (PCI), compared with angiography alone, in patients with stable ischemic heart disease (IHD) and angiographically intermediate stenoses.
Also, FFR use in the overall cohort rose only slightly over the study period, from about 15% in 2009 to 18.5% in 2017. But the proportion of PCIs that were guided by FFR grew more sharply, from 44% to 75%.
The analysis "provides real-world data, outside of clinical trials, showing the significant benefit with FFR-guided PCI versus angiography [alone] in stable patients with intermediate disease," William F. Fearon, MD, Veterans Affairs Palo Alto Health Care System and Stanford University, Palo Alto, California, told theheart.org | Medscape Cardiology.
Further, "it shows an overall mortality benefit, which we haven't seen in previous studies," said Fearon, who is senior author on the analysis, published January 27 in the Journal of the American College of Cardiology, with lead author Rushi V. Parikh, MD, University of California, Los Angeles.
The analysis was based on almost 18,000 patients with stable IHD and coronary lesions of 40% to less than 70% angiographic severity, followed at 66 sites in the Veterans Affairs Clinical Assessment, Reporting, and Tracking (CART) Program. Of those, about 16% had undergone FFR measurement and 84% had received standard angiography only over the entire study period. PCI was performed at the same session or was staged.
Independent predictors of FFR use included more extensive coronary artery disease (CAD), a history of PCI, a family history of CAD, and higher left-ventricular ejection fraction (LVEF). Use of FFR was less likely in older patients and those with peripheral artery disease or a history of heart failure.
Benefit Is "Striking"
The current study indeed shows that FFR is underused in its "core target" patient group, and "indicates that its use is associated with a marked decrease in mortality," agree Julien Adjedj, MD, PhD, Arnault Tzanck Institute, Saint Laurent du Var, France, and Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland, and Benoit Guillon, MDc, University Hospital Jean Minjoz, Besançon, France, in an accompanying editorial.
Even with the limitations of a registry analysis, the mortality difference between the FFR and angiography-only groups "is striking. Even though only 1-year follow-up is provided, the difference in all-cause mortality keeps growing over time," they write.
"In contrast to virtually all previous randomized studies performed in smaller numbers of patients, the difference in outcome is not driven by repeat revascularization — not even by the rate of myocardial infarction — but by all-cause mortality."
Collectively, the trial and now registry evidence suggests that "when performed in the right patients and the right lesions, FFR-guided PCI works, also on hard endpoints," write Adjedj and Guillon. "There is room for increased use of FFR and good reasons to do so."
"Underutilization" Despite Growth
Although FFR "showed a nice increase in usage" over about 8 years, Fearon observed, the numbers still suggest that FFR is underused in such patients. The analysis sheds some light as to why.
Even after adjustment for patient, site, and procedural characteristics, there was still significant variation among sites in use of FFR, even though "the VA Health Care System is not fee-for-service and [is] almost entirely academically affiliated," the report notes.
The results "suggest that the main reason for FFR underutilization in the contemporary era is operator belief regarding the utility of coronary physiology, and that revised reimbursement policies and additional education/training may not have a meaningful impact on FFR adoption," it states
Across the study's 17,989 patients, mortality at 1 year was 2.8% in the group that underwent FFR measurement and 5.9% in the group that underwent angiography without FFR assessment. In adjusted analysis, the mortality hazard ratio for FFR was 0.57 (95% CI, 0.45 - 0.71; P < .0001).
In contrast, the FFR and angiography-only groups showed similar 1-year risks for the composite of myocardial infarction, repeat revascularization, and stroke.
Fearon said the mechanism of reduced mortality in the FFR group is probably a reduction in MI, even though the 1-year risk of MI in the analysis was virtually the same in the FFR and angiography-only groups.
As occurs in many registry studies, he said, it's likely that many MIs were missed, miscoded, or otherwise not documented. "My suspicion is that if we able to get more granular data, we would see a difference in MI."
It also likely explains why the rate of documented MI at 1 year, which was 0.64% in the FFR group and 0.74% for those with angiography only, "is much lower than in previous studies and than what you'd expect in this population."
Fearon discloses receiving research support from Abbott Vascular and Medtronic and holding "minor stock options" with HeartFlow; the other authors report that they have no relevant relationships. Guillon discloses receiving a grant from Sanofi and "participation in a conference" for Abbott. Adjedj reports no relevant conflicts.
J Am Coll Cardiol. Published online January 27, 2020. Abstract, Editorial
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Cite this: Mortality Falls With FFR-Guided PCI of Intermediate Lesions in Registry Study - Medscape - Jan 27, 2020.
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