article83

IFR-SWEDEHEART

"Instantaneous Wave-Free Ratio versus Fractional Flow Reserve in Patients with Stable Angina Pectoris or Acute Coronary Syndrome".

The New England Journal of Medicine. 2017.
ClinicalTrials.gov number, NCT02166736.

1 Clinical Question
2 Bottom Line
3 Major Points
4 Guidelines
5 Design
6 Population
6.1 Inclusion Criteria
6.2 Exclusion Criteria
6.3 Baseline Characteristics
7 Interventions
8 Outcomes
8.1 Primary Outcome
8.2 Secondary Outcomes
9 Funding
10 Further Reading

Clinical Question

Is instantaneous wave-free ratio (iFR) noninferior to fractional flow reserve (FFR) in guiding revascularization and reducing major adverse cardiac events in patients with stable angina or acute coronary syndrome?

Bottom Line

In patients with stable angina or acute coronary syndrome, an iFR-guided revascularization strategy was noninferior to FFR in terms of major adverse cardiac events at 12 months and resulted in less reported chest discomfort during the procedure.

Major Points

The iFR-SWEDEHEART trial found that for guiding revascularization in patients with coronary artery disease, the newer iFR method was noninferior to the established FFR method with regards to major adverse cardiac events within 12 months. This trial also showed that using iFR led to significantly less chest discomfort as it does not require adenosine administration which is needed for FFR.

Guidelines

As of August 2017, no guidelines have been updated to reflect the results of this trial. Previous guidelines recommend using FFR to guide revascularization.

Design

- Multicenter, randomized, controlled, open-label clinical trial
- Participants enrolled from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR)
- N=2,037 participants with stable angina or acute coronary syndrome
- iFR group (n=1,019) vs. FFR group (n=1,018)
- Enrollment: May 2014 to October 2015
- Follow-up: 12 months
- Analysis: Per-protocol
- Primary outcome: Composite of death from any cause, nonfatal myocardial infarction, or unplanned revascularization within 12 months

Population

- Enrollment of 20.3% of presenting patients at trial hospitals with stable angina, unstable angina, or NSTEMI
Inclusion Criteria
- Indication for physiologically guided assessment of coronary artery stenosis (40-80% stenosis)
- Patient consent
Exclusion Criteria
- Excluded technical issues, unacceptable side effects to adenosine, or other specified reasons
Baseline Characteristics
- Mean age: 68 years
- Diabetes mellitus: 21.8%
- Stable angina: 62.0%
- Prior myocardial infarction: 33.0%

Interventions

- Intracoronary nitroglycerin administered before lesion assessment
- iFR-guided or FFR-guided revascularization based on pre-defined thresholds
- Revascularization either performed (PCI or CABG) or deferred based on pressure gradient measurements

Outcomes

Primary Outcome
- Primary end-point event:
- iFR group: 6.7% (68 of 1,012 patients)
- FFR group: 6.1% (61 of 1,007 patients)
- Difference in event rates: 0.7 percentage points (95% CI, -1.5 to 2.8, P=0.007 for noninferiority)
Secondary Outcomes
- Death, nonfatal MI, unplanned revascularization, target-lesion revascularization, stent thrombosis, restenosis
- Chest discomfort during the procedure was significantly higher in FFR group (68.3%) compared to iFR group (3.0%)

Funding

This study was funded by an unrestricted research grant from Philips Volcano to the Uppsala Clinical Research Center.