FFR-Guided Acute Complete Revascularization Studied in COMPARE-ACUTE
March 18, 2017—Pieter Smits, MD, presented findings from the COMPARE-ACUTE trial at ACC.17, the American College of Cardiology's (ACC) 66th annual scientific sessions in Washington, DC. The study evaluated fractional flow reserve (FFR)-guided acute complete revascularization versus treatment of the culprit lesion only in patients presenting with ST-segment elevation myocardial infarction (STEMI) and multivessel disease. The study was simultaneously published by Dr. Smits, et al online in The New England Journal of Medicine.
The background of the study is that under current guidelines, operators typically only treat the blockage responsible for a heart attack; however, patients experiencing a major event often have more than one blocked artery. The COMPARE-ACUTE investigators found that assessing and, when warranted, treating the additional blockages can improve patient outcomes and reduce the need for subsequent invasive procedures, reported the ACC.
According to the ACC announcement, the study’s findings are in line with previous studies showing the benefits of a more comprehensive treatment approach after a major heart attack, but it is the first randomized clinical trial in which operators have used FFR to precisely assess secondary blockages.
Compared with patients in whom operators treated only the blockage that caused the heart attack, patients who underwent FFR-guided evaluation and treatment of all arteries were 65% less likely to experience the trial’s primary endpoint, a composite of all-cause mortality, nonfatal heart attack, stroke, and subsequent revascularization at 12 months.
In the ACC press release, Dr. Smits commented, “Our study shows you can optimize treatment with this approach and potentially also have economic benefits by reducing the need for extra procedures. For the patient, it’s a tremendous advantage to know that you have been treated for the artery that brought you to the hospital but also that any other issues have already been investigated and treated if needed. This way the patient won’t need to be brought back to the hospital later on and again be put at risk with an invasive procedure or additional diagnostics.”
As summarized by the ACC, the COMPARE-ACUTE investigators sought to investigate whether FFR could offer an opportunity to improve outcomes by refining operators’ ability to identify problematic lesions immediately after successful initial percutaneous coronary intervention (PCI). FFR provides a much more accurate assessment of blockages than was previously possible with angiography alone because it is based on precise blood pressure measurements near lesions.
The investigators enrolled 885 STEMI patients at 24 sites in 12 countries in Europe and Asia. Immediately after the infarct-related artery was treated by PCI, stable patients were randomly assigned to undergo FFR-guided assessment of other arteries but no additional PCI (infarct-only revascularization, performed in 590 patients) or FFR-guided assessment and, when indicated by an FFR score of 0.8 or lower, PCI to treat additional lesions (complete revascularization, performed in 295 patients).
The primary composite endpoint occurred in 20.5% of patients who underwent infarct-only revascularization and 7.8% of patients who underwent FFR-guided complete revascularization, a difference that was statistically significant.
When the components of the composite primary endpoint were analyzed separately, there was no significant difference in the rates of all-cause mortality, nonfatal heart attack, or stroke; however, there was a significant reduction in the incidence of subsequent revascularization procedures among patients randomized to undergo complete revascularization.
All nonurgent revascularization procedures performed within the first 45 days after the initial PCI based on symptoms or stress tests were excluded from this analysis to avoid biasing the results in favor of complete revascularization.
When assessing the lesions other than the one responsible for the heart attack, the investigators found that only about half of these lesions required treatment. Together, these results suggest that treating noninfarct-related lesions is beneficial and that FFR can help clinicians to precisely identify those lesions in need of treatment, concluded the investigators.
Dr. Smits stated, “The results show that using FFR in the acute phase of STEMI, which was never done before, is feasible and safe. Furthermore, FFR-guided complete revascularization allows you to fine-tune the treatment and get better outcome results.”
The ACC announcement noted that one downside of performing complete revascularization after initial PCI is that doing so increases the complexity of the procedure. However, the results showed that procedures in the complete revascularization arm were on average just 6 minutes longer than the procedures in the infarct-only revascularization arm, a difference that Dr. Smits said is relatively minor and likely outweighed by the increased need for subsequent revascularization among those undergoing infarct-only revascularization in the initial procedure.
Additionally, a limitation of the study is that investigators struggled with slow enrollment, in part because some participating centers were only able to enroll patients during certain hours of the day or week and because the trial excluded patients who were in shock or unstable, a relatively frequent occurrence with STEMI. The study enrolled patients from 2011 to 2015.
Another limitation is that the study was not large enough to reveal statistically significant differences in all-cause mortality or subsequent heart attacks. A larger study, currently underway, is expected to evaluate these outcomes. In addition, the investigators plan to conduct a further analysis of the cost implications of performing infarct-only revascularization versus complete revascularization after STEMI.
COMPARE-ACUTE was funded by two unrestricted grants from Abbott Vascular and St. Jude Medical, advised the ACC.