Author + information
- 1Northwick Park Hospital, London, United Kingdom
- 2Brighton and Sussex Medical School, Brighton, United Kingdom
- 3Brighton and Sussex University Hospitals, Overijse, United Kingdom
- 4Golden Jubilee National Hospital, Glasgow, United Kingdom
- 5Cardiovascular Research Foundation, Columbia University Medical Center/NewYork-Presbyterian Hospital, New York, New York, United States
To evaluate the safety and efficacy of intracoronary (IC) adenosine infusion using a HYPEREM™ FFR infusion microcatheter compared with the standard intravenous (IV) method.
The HYPEREMIC study was a randomized single blinded crossover investigation to evaluate the effectivenes and safety of a novel dedicated over-the-wire infusion micro-catheter (HYPEREM™IC) for measuring FFR using IC non-weight adjusted adenosine infusion versus the standard IV method. FFR measurements were performed sequentially using standard IV adenosine (140-180mcg/kg/min) followed by the HYPEREM™IC FFR microcatheter with non-weight adjusted IC adenosine (360mcg/min) or vice versa. All patients were blinded to the order in which they received adenosine with a 3 minute washout period. The primary endpoint was non-inferiority between the IC infusion versus the IV. Secondary endpoints were incidence and severity of side effects, time to hyperemia, dose and duration of adenosine.
A total of 41 patients were randomized in 3 UK sites. The mean (SD) peak FFR was 0.84 (±0.09) IV versus 0.82 (±0.09) IC (p=0.0008). There was no evidence of a period effect (p=0.90) or a period/procedure interaction (p=0.75) allowing for the planned analysis to proceed using within-patient differences. Differences in FFR (IC minus IV), revealed a mean of -0.02 with a 95% confidence interval of -0.03 to -0.01, which confirmed that IC was non-inferior. 31.7% (13/41) of lesions were at or below the 0.8 threshold with IC infusion method compared to only 22% (9/41) with the IV method. No patients with a functionally ischaemic stenosis(es) were classified incorrectly by IC infusion. Time (mean ± SD) in seconds to achieve peak FFR was 84 (±37) IV vs. 40 (±24) IC (p<0.0001). Duration of adenosine infusion was 105 (±33) for IV vs. 57 (±35) for IC (p<0.0001). Patients experienced more chest discomfort during IV 78% vs. 29% during IC. No patients reported severe chest discomfort with IC infusion compared to 12.2% during IV.
IC adenosine infusion is a reliable, faster and better tolerated method of achieving maximal hyperemia compared to IV. The total IC dose required is about 1.5% of the equivalent IV dose yet achieved a more rapid and stable state of hyperemia. Moreover, FFR values were consistently lower with IC infusion with more lesions classified as ischemic. This suggests we may be failing to achieve maximal hyperemia in a proportion of patients undergoing physiological assessment.
IMAGING: FFR and Physiologic Lesion Assessment