title: Myocardial stress perfusion magnetic resonance: initial experience in a pediatric and young adult population using regadenoson.
abstract: BACKGROUND
  Dipyridamole and adenosine are traditional pharmacological stressors for myocardial perfusion. Regadenoson, a selective adenosine A2A agonist, has a lower side effect profile with lower incidence of bronchospasm and bradycardia. There is a growing need for myocardial perfusion assessment within pediatrics. There is no report on the utility of regadenoson as a stress agent in children.
  
  
  OBJECTIVE
  To observe the safety and feasibility of regadenoson as a pharmacologic stressor for perfusion cardiac MR in a pilot cohort of pediatric patients weighing more than 40 kg who have congenital heart disease and pediatric acquired heart disease.
  
  
  METHODS
  We reviewed our initial experience with regadenoson stress cardiac MR in 31 pediatric patients 15.8 ± 1.7 years (range 12-22 years) with congenital heart disease and acquired heart disease. Mean patient weight was 60 ± 15 kg (range of 40-93 kg). All patients underwent cardiac MR because of concern for ischemia. The cohort included a heterogeneous group of patients at a pediatric institution with potential risk for ischemia. Subjects' heart rate and blood pressure were monitored and pharmacologic stress was induced by injection of 400 mcg of regadenoson. We evaluated their hemodynamic response and adverse effects using changes in vital signs and onset of symptoms. A pediatric cardiologist and radiologist qualitatively assessed myocardial perfusion and viability images.
  
  
  RESULTS
  One child was unable to complete the stress perfusion portion of the examination, but did complete the remaining portion of the CMR. Resting heart rate was 72 ± 14 beats per minute (bpm) and rose to peak of 124 ± 17 bpm (95 ± 50% increase, P < 0.005) with regadenoson. Image quality was considered good or diagnostic in all cases. Three patients had irreversible perfusion defects. Four patients had reversible perfusion defects. Nine of the patients underwent cardiac catheterization with angiography and the findings showed excellent agreement.
  
  
  CONCLUSIONS
  Regadenoson might be a safe and feasible pharmacologic stress agent for use in cardiac MR in older pediatric patients with congenital heart disease and acquired heart disease. The ease of use as a bolus and the advantage of a prolonged hyperemia make its use appealing in pediatrics. In a limited number of cases, regadenoson stress perfusion showed excellent agreement with cardiac catheterization. Regadenoson might be a viable pharmacologic stress agent in this population.
authors.affiliation: Department of Pediatric Cardiology, Baylor College of Medicine, Houston, TX, USA. cvnoel@texaschildrens.org.|Department of Pediatric Cardiology, Texas Children's Hospital, 6621 Fannin St., MC 19345-C, Houston, TX, 77030, USA. cvnoel@texaschildrens.org.
authors.forename: Cory V
authors.initials: CV
authors.lastname: Noel
authors.affiliation: Department of Radiology, Texas Children's Hospital, Houston, TX, USA.
authors.forename: Ramkumar
authors.initials: R
authors.lastname: Krishnamurthy
authors.affiliation: Department of Pharmacology, Texas Children's Hospital, Houston, TX, USA.
authors.forename: Brady
authors.initials: B
authors.lastname: Moffett
authors.affiliation: Department of Radiology, Texas Children's Hospital, Houston, TX, USA.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Krishnamurthy
mesh_terms: D058908:Adenosine A2 Receptor Agonists / Q000008:administration & dosage*; D000293:Adolescent; D002318:Cardiovascular Diseases / Q000000981:diagnostic imaging*; D002648:Child; D005080:Exercise Test; D005240:Feasibility Studies; D005260:Female; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010865:Pilot Projects; D011687:Purines / Q000008:administration & dosage*; D011720:Pyrazoles / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D058908:Adenosine A2 Receptor Agonists; D011687:Purines; D011720:Pyrazoles; C430916:regadenoson
keywords: Acquired coronary artery disease; Children; Congenital heart disease; Heart; Magnetic resonance imaging; Pharmacologic stress; Regadenoson; Stress perfusion