Diagnostic and prognostic characteristics of currently invasive coronary physiology indices. FFR, fractional flow reserve; iFR, instantaneous wave-free ratio; RFR, resting full-cycle ratio; DFR, diastolic hyperaemia-free ratio; IMR, index of microcirculatory resistance; RRR, resistive reserve ratio; HMR, hyperaemic microvascular resistance; AMR, absolute microvascular resistance; MRR, microvascular resistance reserve.