SCMR 22nd Annual Scientific Sessions
Description of Clinical Presentation:
Myocardial perfusion assessment is increasingly used to detect myocardial ischemia in pediatric patients. Regadenoson is a selective myocardial stressor that has recently been demonstrated to be an efficacious physiologic stressor in pediatric patients with congenital and acquired heart disease. In two pediatric patients with Kawasaki disease (KD) regadenoson was used as pharmacologic stressor in CMR assessment of myocardial perfusion defects. Stress-myocardial first-pass perfusion was performed 60 seconds after administration of 0.4 mg of regadenoson, with 0.1 mmol/kg of gadolinium at a rate of 3 mL/s. Upon the return of heart rate to close to baseline, rest-first-pass perfusion was performed with 0.1 mmol/kg of gadolinium.
Diagnostic Techniques and Their Most Important Findings:
The first patient was a 15 year old female with KD diagnosed at age three. Initial coronary involvement consisted of giant aneurysms of right and left coronary systems that regressed to small aneurysms of the left coronary system and complete resolution of right system. She remained clinically asymptomatic on aspirin therapy. Screening exercise stress test demonstrated normal exercise capacity with no electrocardiographic abnormalities or symptoms.
CMR demonstrated stable mild residual fusiform dilation of distal left main coronary artery and proximal left anterior descending and circumflex coronary arteries. With stress first pass perfusion there was subendocardial perfusion defects in the distribution of the left anterior descending (LAD) that were not noticed at resting perfusion. Subsequent cardiac catheterization showed focal area of stenosis in the proximal LAD and circumflex and abnormal fractional flow reserve in the left coronary system, corroborating perfusion imaging findings. The patient is being considered for surgical versus catheterization based intervention.
The second patient was a 4 year old male with KD diagnosed at age of two years. He had coronary involvement that included giant aneurysms of the left main coronary, left anterior descending artery, and right coronary artery.
CMR evaluation was notable for stable giant aneurysms of the left coronary system and hyopkinesis of the basal anteroseptal segment in the distribution of the LAD with normal global left ventricular function. Myocardial perfusion imaging demonstrated a fixed perfusion defect in basal and mid anteroseptal and reversible defect in the apical septal segment, with transmural late gadolinium enhancement of basal anteroseptal segment. Subsequent cardiac catheterization showed near total occlusion of LAD and giant aneurysm with potential thrombus. The patient is scheduled for surgical coronary artery bypass graft surgery.
Learning Points from this Case:
Compared to previous continuous infusions, the ability to administer Regadenoson as a single bolus with one IV makes it advantageous in children. In these two cases, stress CMR showed excellent agreement with cardiac catheterization in KD and augmented decision making.