Abstract 19777: How Physiological is Adenosine-Induced Hyperaemia? Insights From Exercise in the Catheterisation Laboratory
Introduction: Fractional flow reserve during adenosine-induced hyperaemia (FFR) is frequently considered a surrogate for inducible myocardial ischaemia on exercise; however it is unclear whether the stresses are comparable.
Hypothesis: The mechanism of flow augmentation with exercise is different to that of adenosine.
Methods: Patients undergoing coronary angiography were assessed with a dual pressure-flow sensing intracoronary wire at rest, whilst performing on-table supine bicycle ergometry and during adenosine-induced hyperaemia. Aortic pressure (Pa), distal coronary pressure (Pd) and flow velocity were recorded at peak exercise and hyperaemia. Mean Pd/Pa was calculated for both stresses (FFR, exercise Pd/Pa). Wave intensity analysis was used to investigate the mechanisms governing flow.
Results: Forty-two patients performed the protocol, attaining a mean heart rate of 75% of age predicted maximum. Rate pressure product (reflecting myocardial work) rose from 11x103±3x103 bpm.mmHg at rest to 13x103±3x103 bpm.mmHg with adenosine and 21x103±7x103 bpm.mmHg with exercise. Mean FFR and exercise Pd/Pa were similar (0.88±0.08 vs. 0.90±0.09, p=0.131), but only moderately correlated (Spearman’s rho 0.57) (figure 1).
Doppler flow velocity was assessed throughout in 18 patients. Mean velocity increased from 18.1±6.3cms-1 at rest to 38.7±16.8cms-1 with adenosine and 28.1±7.4cms-1 with exercise. Coronary perfusion was more efficient during exercise (84±6% of total wave energy accelerating flow) than adenosine hyperaemia (77±12%, p = 0.02). This was due to augmentation of diastolic suction, with the backward expansion wave contributing 58±11% of total wave energy during exercise compared with 50±10% during adenosine (p = 0.02).
Conclusions: Adenosine decreases microvascular resistance but does not reproduce the complex cardiac-coronary coupling that occurs with exercise. This may explain why FFR does not correlate well with Pd/Pa during exercise.
- Coronary microcirculation
- Heart catheterization
- Interventional cardiology
- Percutaneous coronary intervention (PCI)
Author Disclosures: M. Ryan: None. B. Modi: None. S. Arri: None. K. Asrress: None. M. Lumley: None. R. Williams: None. H. Ellis: None. B. Clapp: None. M. Marber: Ownership Interest; Modest; Marber is named as an inventor on a patent held by King’s College London for the detection of cardiac myosin binding protein-C as a biomarker of myocardial injury.. S. Redwood: None. D. Perera: None.
- © 2016 by American Heart Association, Inc.