Instantaneous wave-free ratio as an alternative to fractional flow reserve in assessment of moderate coronary stenoses: A meta-analysis of diagnostic accuracy studies

Cardiovasc Revasc Med. 2018 Jul-Aug;19(5 Pt B):613-620. doi: 10.1016/j.carrev.2017.12.014. Epub 2017 Dec 27.

Abstract

Background/purpose: Fractional flow reserve (FFR) remains underutilized due to practical concerns related to the need for hyperemic agents. These concerns have prompted the study of instantaneous wave-free ratio (iFR), a vasodilator-free index of coronary stenosis. Non-inferior cardiovascular outcomes have been demonstrated in two recent randomized clinic trials. We performed this meta-analysis to provide a necessary update of the diagnostic accuracy of iFR referenced to FFR based on the addition of eight more recent studies and 3727 more lesions.

Methods: We searched the PubMed, EMBASE, Central, ProQuest, and Web of Science databases for full text articles published through May 31, 2017 to identify studies addressing the diagnostic accuracy of iFR referenced to FFR≤0.80. The following keywords were used: "instantaneous wave-free ratio" OR "iFR" AND "fractional flow reserve" OR "FFR."

Results: In total, 16 studies comprising 5756 lesions were identified. Pooled diagnostic accuracy estimates of iFR versus FFR≤0.80 were: sensitivity, 0.78 (95% CI, 0.76-0.79); specificity, 0.83 (0.81-0.84); positive likelihood ratio, 4.54 (3.85-5.35); negative likelihood ratio, 0.28 (0.24-0.32); diagnostic odds ratio, 17.38 (14.16-21.34); area under the summary receiver-operating characteristic curve, 0.87; and an overall diagnostic accuracy of 0.81 (0.78-0.84).

Conclusions: In conclusion, iFR showed excellent agreement with FFR as a resting index of coronary stenosis severity without the undesired effects and cost of hyperemic agents. When considering along with its clinical outcome data and ease of application, the diagnostic accuracy of iFR supports its use as a suitable alternative to FFR for physiology-guided revascularization of moderate coronary stenoses.

Summary: We performed a meta-analysis of the diagnostic accuracy of iFR referenced to FFR. iFR showed excellent agreement with FFR as a resting index of coronary stenosis severity without the undesired effects and cost of hyperemic agents. This supports its use as a suitable alternative to FFR for physiology-guided revascularization of moderate coronary stenoses.

Keywords: Coronary physiology; Diagnostic accuracy; Fractional flow reserve; Instantaneous wave-free ratio.

Publication types

  • Meta-Analysis
  • Review

MeSH terms

  • Aged
  • Cardiac Catheterization / methods*
  • Coronary Artery Disease / diagnosis*
  • Coronary Artery Disease / physiopathology
  • Coronary Stenosis / diagnosis*
  • Coronary Stenosis / physiopathology
  • Coronary Vessels / physiopathology*
  • Female
  • Fractional Flow Reserve, Myocardial*
  • Humans
  • Hyperemia / physiopathology
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Prognosis
  • Reproducibility of Results
  • Severity of Illness Index
  • Vasodilator Agents / administration & dosage

Substances

  • Vasodilator Agents