instantaneous wave-free ratio
Adenosine-free physiological index for assessing coronary stenosis significance during cardiac catheterization.
Full Definition
Instantaneous wave-free ratio (iFR) is a physiological assessment tool that evaluates the hemodynamic significance of coronary stenoses without the need for adenosine-induced hyperemia. iFR is calculated during the wave-free period of diastole when competing microvascular flows are naturally minimized. An iFR value ≤0.89 indicates hemodynamically significant stenosis. iFR has been shown to be non-inferior to FFR for guiding revascularization decisions while offering advantages of shorter procedure time, reduced patient discomfort, and lower cost due to elimination of adenosine administration.
Usage
Usage note: Abbreviated as iFR with lowercase 'i'; distinguish from FFR by noting absence of hyperemia.
In Context
- "iFR assessment revealed a value of 0.85, indicating need for revascularization." — interventional cardiology report
- "The instantaneous wave-free ratio provided rapid physiological assessment without adenosine." — cardiac catheterization procedure note