title: Intracoronary versus intravenous adenosine-induced maximal coronary hyperemia for fractional flow reserve measurements.
abstract: BACKGROUND
  Maximal hyperemia is the critical prerequisite for fractional flow reserve (FFR) assessment. Despite intravenous (IV) adenosine currently being the recommended approach, intracoronary (IC) administration of adenosine constitutes a valuable alternative in everyday practice. However, it is surprisingly unclear which IC strategy allows the achievement of FFR values that are comparable to IV adenosine.
  
  
  OBJECTIVE
  This study sought to compare increasing doses of IC adenosine versus IV adenosine for FFR.
  
  
  METHODS
  30 intermediate coronary stenoses undergoing FFR measurement were prospectively and consecutively enrolled. Hyperemia was sequentially induced by bolus of IC adenosine (ADN; 150 μg) followed by IV adenosine (IVADN) infusion over 3 minutes at dose of (140 μg/kg/min). FFR values, symptoms, and development of atrioventricular block were recorded.
  
  
  RESULTS
  150 μg doses of IC adenosine were well tolerated and associated with fewer symptoms than IV adenosine. Intracoronary adenosine doses induced a significant decrease of FFR compared with baseline levels (P < 0.01). Among the 6 patients with FFR values less than 0.80 identified by IVADN, 4 were correctly identified also by 150 μg bolus IC adenosine. Larger randomized studies with cross-over design are necessary to verify the results.
  
  
  CONCLUSIONS
  This small pilot study suggests that IC adenosine might be an alternative to IV adenosine. Larger randomized studies with a cross-over design are necessary.
authors.affiliation: Ain Shams University, Cardiology Department Cairo, Egypt.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Khashaba
authors.affiliation: Ain Shams University, Cardiology Department Cairo, Egypt.
authors.forename: Ayman
authors.initials: A
authors.lastname: Mortada
authors.affiliation: Ain Shams University, Cardiology Department Cairo, Egypt.
authors.forename: Azza
authors.initials: A
authors.lastname: Omran
keywords: AVB: atrioventricular- nodal block; CAD: Coronary artery disease; CBF: Coronary blood flow; FAME: FFR versus angiography for multi vessel evaluation; FFR: Fractional flow reserve; IC: Intracoronary; ICADN Intracoronary Adenosine; IV: Intravenous; IVADN: intravenous Adenosine; PCI: percutaneous coronary intervention; QCA: quantitative coronary Angiography