Regadenoson Shows Promise in Measuring Fractional Flow Reserve

San Francisco, CA—Regadenoson yielded similar Fractional Flow Reserve (FFR) measurements as adenosine in a cohort of patients with angiographic CAD.

Lokien van Nunen MD, of Catharina Hospital Eindhoven in Eindhoven, Netherlands, and colleagues, evaluated A2A-receptor regadenoson and compared two strategies for measuring FFR: a single bolus regadenoson injection and a central venous adenosine infusion. Within the regadenoson group, central venous and peripheral injections were administered.

“Adenosine, the present gold standard for inducing maximum coronary hyperemia, is reliable, safe and well investigated,” van Nunen said. “However, in some countries there may be a barrier for its use due to non-trivial preparation, high price and need for central venous access. An alternative is regadenoson, which is a hyperemic stimulus administered as a single, non-weight based bolus injection in a peripheral vein.”

The outcomes that underwent analysis included time intervals to onset and duration of steady state maximum hyperemia. Safety of repeated injections of the study drug served as the primary adverse event outcome.

The analysis included 50 patients with angiographic intermediate CAD. Eligible participants were scheduled for an FFR measurement.

Two central venous adenosine (140 mcg/kg per minute) measurements were taken, along with two central or peripheral venous regadenoson bolus injections (400 mcg). Clinicians performed the measurements in a randomized sequence.

In 60% of the participants who underwent investigation, stenosis was located in the left anterior descending artery. Of the remaining proportion, stenosis was located in the circumflex in 28% and in the right coronary artery in 11%.

No difference was observed in the FFR measurements by adenosine or regadenoson (R2=0.981; ΔFFR=0.00±0.02; P<.001). There was also no difference between repeated bolus injections of the study drug (R2=0.971; ΔFFR=0.00±0.02; P<.001).

Results indicated a time to onset of hyperemia of 29±12 seconds. Although maximum hyperemia lasted 151 seconds, the variation in this interval was between 15 and greater than 600 seconds.
The researchers reported no noticeable adverse events associated with regadenoson.

 “This is the first study to not only look at maximum hyperemia induced by regadenoson, but also investigate duration of steady state hyperemia, different ways of administration, reproducibility and safety of repeated regadenoson injections,” van Nunen said. “It will change practice for clinicians. In patients with complex coronary artery disease, where extensive pressure-pullback recordings and prolonged maximum coronary hyperemia are necessary, adenosine remains mandatory. In diagnostic coronary angiography with ad-hoc measurement of FFR in 1 or 2 focal lesions, regadenoson is an excellent alternative and can be administered via peripheral venous access.”

The mean patient age was 65±8 years. Men comprised 80% of the population.

Regadenoson is a selective hyperemic stimulus marked by rapid onset and an easy administration method, according to the investigators.

Dr. Van Nunen reports no relevant conflicts of interest. Dr. Pijls receives research grants from Rapidscan Pharma Solutions and St. Jude Medical.

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