Table 4.

Summary of main instantaneous wave free ratio trials

Trial	Study population	Mean FFR value +/-SD	Mean iFR-value +/-SD	iFR cut-off	P value for non-inferiority	Correlation	Sensitivity %	Specificity %
DEFINE-FLAIR[13]	2492	0.83 +/-0.09	0.91+/- 0.09	0.89	< 0.001
iFR SWEDEHEART[12]	2037	0.82 +/-0.10	0.91+/- 0.10	0.89	0.007
ADVISE study[59]	131	0.72+/- 0.2		0.83		0.9 (P < 0.001)	85	91
VERIFY[65]	206			0.83		0.67	54 (49-60)	96 (95-99)
JUSTIFY-CFR[61]	186	0.74+/- 0.17	0.81+/- 0.21	0.89		0.68 0.60-0.76	73	74

FFR: Fractional flow reserve; SD: Standard deviation. Table 4 summarize the primary studies evaluating the instantaneous wave free ratio (iFR). These trials have evaluated the correlation rate between iFR and FFR value and showed that iFR guided- percutaneous interventions (PCI) could be an alternative to FFR guided-PCI.