Abstract 15071: Persistent Hemodynamic Variability during Intravenous Adenosine Administration Affects Fractional Flow Reserve Assessment despite Stable Stenosis Hemodynamics as Expressed by Its Pressure Drop-Velocity Relationship
Background: Intravenous (iv) adenosine administration is thought to provide maximal and stable hyperemia for the assessment of functional coronary artery stenosis severity. When only intracoronary pressure is acquired, the lowest FFR during hyperemia is used for clinical decision-making. The aim of this study was to investigate the effects of iv adenosine on coronary hemodynamics and on the assessment of functional stenosis severity.
Methods: In 14 diseased vessels (25 to 57% diameter stenosis), flow velocity (v), aortic (Pa) and distal pressure (Pd) were simultaneously measured during 2 minutes of iv adenosine infusion (140 μg/kg/min). We defined 3 time points: t0, when v reached 10% above baseline; t1, time of maximal v; t2, when v started to decline. Hemodynamic variability between t1 and t2 was assessed by intrapatient coefficient of variation (CV). At baseline, at t1 and at the time of minimum FFR (= Pd/Pa) we evaluated cycle-averaged pressure and velocity signals, FFR, CFR, microvascular (MR= Pd/v) and stenosis (SR= ΔP/v) resistance. Stenosis ΔP-v relations were also derived throughout the hyperemic response.
Results: Hemodynamic conditions were generally not stable during hyperemia (from t1 to t2) and CV ranged from 3-12% for Pa and Pd, from 3-26% for v, and from 3-27% for MR and SR. Maximal v (54 ± 5 cm/s) was reached 29 ± 3 s after t0, with FFR= 0.83 ± 0.01 and CFR= 2.83 ± 0.23. Minimal FFR (0.82 ± 0.01) occurred 48 ± 7 s after t0, when Pa and Pd had declined by 7 and 9%, respectively, and v was 5% less than at t1, with CFR= 2.68 ± 0.23 (p<0.01 for all). MR and SR did not differ at t1 and at FFRmin (p>0.05). Functional significance (FFR ≤ 0.80) was reached by 21% more lesions at FFRmin than at maximal v. Despite this variability, ΔP-v relations remained remarkably stable and reliably followed a quadratic relationship during the infusion (r= 0.97 ± 0.01).
Conclusions: In conclusion, minimal FFR occurred 19 ± 7 s after maximal flow velocity and was due to pressure decrease mediated by systemic adenosine infusion rather than maximal coronary dilation. FFR at peak hyperemia should be considered rather than FFRmin to avoid unnecessary treatment. In contrast, the stenosis ΔP-v relation is preserved indicating stable stenosis hemodynamics.
- Coronary artery disease
- Intravascular ultrasound/Doppler
- Interventional cardiology
Author Disclosures: L. Casadonte: None. K.M. Marques: None. J.A. Spaan: None. M. Siebes: None.
- © 2014 by American Heart Association, Inc.