Revascularisation on non-infarct-related lesions during primary PCI in STEMI patients
Fractional Flow Reserve–Guided Multivessel Angioplasty in Myocardial Infarction
Presented at ACC.17 by Pieter C Smits
In STEMI patients with multi-vessel disease, the infarct-related coronary artery is treated acutely with PCI and stent implantation, but the non-infarct-related coronary artery (non-IRA) lesions are not. During coronary angiography the assessment of the functional severity of a lesion may lead to overtreatment, with additional costs and risks. The fractional flow reserve (FFR) is used for the evaluation of the functional severity of coronary lesions in patients with stable coronary artery disease and is helpful for the decision making of whether or not a PCI will be of benefit.
In this study, FFR was used to guide treatment decisions regarding the non-IRA lesions, in 885 patients presenting with STEMI and multi-vessel disease. In a ratio of 1:2, patients were randomised to acute FFR-guided complete revascularisation of non-IRA lesions, or to IRA-only treatment plus blinded FFR of non-IRA lesions. The primary outcome was MACCE, a composite of cardiac death, myocardial Infarction, any revascularization, stroke and major bleeding.
- According to FFR measurements, the distribution of significant flow-limiting lesions in non–infarct-related coronary arteries was similar in the two groups.
- In the complete-revascularisation group, 54.1% had one or more lesions in non–infarct-related coronary arteries, with an FFR ≤ 0.80, and underwent PCI of these lesions.
- In the infarct-artery-only group, 47.8% had one or more lesions in non-infarct-related coronary arteries with an FFR ≤ 0.80.
- FFR was associated with 2 serious adverse events, brief episodes of AV conduction delay and moderate drops in BP.
- At 1 year, the primary outcome had occurred in 7.8% of patients in the complete-revascularization group and in 20.5% of patients in the infarct-artery-only group (HR: 0.35; 95% CI: 0.22 - 0.55; P<0.001).
- The HRs for the comparison of the individual components of the composite end point in the two groups were as follows: all-cause mortality: 0.80; 95% CI: 0.25 - 2.56; P = 0.70; non-fatal re-infarction: 0.50; 95% CI: 0.22 - 1.13; P = 0.10; revascularization: 0.32; 95% CI: 0.20 - 0.54; P<0.001.
- Pre-specified subgroup comparisons showed a significantly lower rate of MACCE among patients with treated lesions compared with patients with untreated lesions with an FFR ≤ 0.80 (8.9% vs. 30.7%; P<0.001).
In STEMI patients with multi-vessel disease, FFR-guided complete revascularisation of non–infarct-related lesions in the acute phase of primary PCI, reduced the risk of a composite CV outcome compared with the treatment of the infarct-related artery only. These findings suggest that FFR might be useful for deciding whether non-infarct-related arteries should be re-opened in the acute STEMI setting, or not.
In his editorial article, Køber doubts that the results of the Smits et al study can be extrapolated to every day clinical practice, since the patients included in the study had a lower risk than average, and were not negatively influenced by the prolongation of the index procedure. Moreover, information about eligible patients who were not randomised is missing, and the treatment allocation was not blinded. The author concludes:
‘When considered together with previously published data, the report by Smits and colleagues indicates that a strategy of FFR-guided complete revascularization results in lower rates of major adverse cardiovascular events and of revascularization procedures performed than a strategy based only on angiography. However, the cardiovascular benefit was driven largely by revascularization. Larger trials powered for hard end points (recurrent myocardial infarction or cardiovascular mortality) are needed to determine the effects of an FFR-guided complete-revascularization strategy on these outcomes and to identify the subgroups of patients most likely to benefit (recruitment is ongoing in one trial of 3900 patients [ClinicalTrials.gov number, NCT01740479]).’