Adenosine Administration for FFR Measurement
For fractional flow reserve (FFR) measurement, administer adenosine as a continuous intravenous infusion at 140 μg/kg/min for at least 2 minutes to achieve maximal hyperemia. 1
Route and Dosing
Intravenous continuous infusion is the gold standard for FFR measurement, administered through a large-bore cannula in a large vein at 140 μg/kg/min 1
Infusion duration must be at least 2 minutes to achieve steady-state maximal hyperemia before calculating FFR 1
Peripheral venous access via hand vein is acceptable when central venous access is unavailable (particularly during transradial procedures), though it takes longer to reach peak hyperemia (63 seconds vs 43 seconds for femoral vein) but produces equivalent FFR values 2, 3
Critical Technical Points
Administer nitrates first: Give intracoronary isosorbide dinitrate 2 mg (or nitroglycerin 200 μg) at least 2 minutes before adenosine to abolish epicardial vasoconstrictor tone 1
Calculate FFR at the nadir of distal pressure (Pd) during steady-state hyperemia, measured as the ratio of Pd to aortic pressure (Pa) 1
Continuous infusion is superior to bolus administration because it allows for pressure pullback curves to differentiate focal from diffuse disease and permits measurement at ostial lesions 1
Alternative Dosing Considerations
While intracoronary bolus adenosine is sometimes used in practice, the evidence shows important limitations:
Standard intracoronary doses (60-300 μg) are inadequate: They produce significantly higher FFR values than IV infusion, potentially missing functionally significant stenoses 4, 5
Very high intracoronary doses (600 μg) approach IV equivalence but still show variability and are not officially recommended 4, 6
Intracoronary boluses create artifacts from the injection itself that complicate analysis and should be avoided during continuous IV infusion 1
10% of patients with borderline FFR values using 60 μg intracoronary bolus were reclassified as functionally significant when IV adenosine was used 5
Common Pitfalls to Avoid
Guiding catheter damping: Disengage the catheter if pressure waveform shows ventricularization during measurement, as this impairs coronary flow and falsely elevates FFR 1
Inadequate infusion time: Measuring FFR before 2 minutes of infusion may not capture true maximal hyperemia 1
Adding intracoronary boluses during IV infusion: This does not improve hyperemic efficacy but increases risk of atrioventricular block 3
Pressure drift: Verify equal pressures between pressure wire and guiding catheter at procedure end; drift >5 mmHg requires repeat measurement 1
FDA-Approved Dosing for Myocardial Perfusion Imaging
The FDA label specifies 0.14 mg/kg/min (140 μg/kg/min) infused over 6 minutes for nuclear perfusion studies, confirming this dose achieves maximal coronary hyperemia in approximately 95% of cases within 2-3 minutes 7