While pharmacologic stress cardiovascular magnetic resonance (PSCMR) has been well-studied in adults with stable ischemic heart disease, research has been lacking in the pediatric field. In a review published in Congenital Heart Disease, researchers examined the implications of PSCMR in a pediatric population. They also studied 2 cases of patients with Kawasaki disease.
Investigators identified 4 cohorts of high-risk pediatric patients, with either congenital or acquired heart disease who could benefit from a myocardial perfusion assessment by PSCMR. These cohorts and the role of PSCMR are outlined below:
Surgical coronary reimplantation: Subsets of patients include the arterial switch operation, the double-switch operation in the setting of congenitally corrected transposition of the great arteries, the Ross procedure, and anomalous left coronary artery from the pulmonary artery (ALCAPA). PSCMR for evaluation of myocardial ischemia has been reported following the arterial switch operation; excellent agreement with imaging results has been demonstrated. PSCMR has been successfully performed following the Ross procedure and ALCAPA.
Anomalous coronary artery origin or course: PSCMR has been reported as having potential in both anomalous aortic origin of the coronary arteries and myocardial bridges.
Acquired coronary artery disease: This group primarily comprises patients with Kawasaki disease. PSCMR should be considered as a method of long-term follow-up because of the involvement of the coronary artery.
Systemic right ventricle: Research has indicated that PSCMR can detect right ventricular dysfunction by assessment of the myocardial reserve.
The diagnostic accuracy and safety profile of PSCMR have been shown to be superior to other stress imaging modalities among adults; however, the use of this diagnostic tool is still evolving in the pediatric population. Limitations of PSCMR are multifactorial, including a lack of experience and familiarity with this modality. In children and young adults, pharmacologic stress echocardiography is limited due to variability in image acquisition and experience.
Investigators of the study also presented 2 cases of patients with Kawasaki disease:
In the first case, a 15-year-old girl developed giant aneurysms of the left and right coronary artery systems. Over time, a regression of the aneurysms was noted, and a surveillance treadmill exercise stress test demonstrated normal exercise capacity. CMR evaluation was used to identify stable, mild residual fusiform dilation of the distal left main coronary artery, proximal left anterior descending (LAD), and circumflex coronary arteries. Subendocardial perfusion defects of the LAD not found at rest perfusion, as seen by stress first-pass perfusion. The patient underwent catheterization-based rotational atherectomy and cutting balloon dilation.
The second case was of a 4-year-old boy with Kawasaki disease who developed giant aneurysms in the left main LAD and right coronary arteries. Giant aneurysms on the left coronary system and hypokinesis of the basal anteroseptal segment in the LAD distribution were seen by CMR evaluation. Myocardial perfusion imaging demonstrated fixed perfusion defect in the basal- and mid-anteroseptal walls. The patient underwent coronary artery bypass graft of the LAD and posterior descending coronary arteries.
“The role and utilization of PSCMR continue to evolve in the evaluation of pediatric age patients with congenital and acquired heart disease at high risk for myocardial ischemia,” the researchers concluded. “Additional studies will hopefully add to our understanding of the indications, benefits, and pitfalls of this robust noninvasive imaging tool and its potential impact in management and prognostication.”
Fares M, Critser PJ, Arruda MJ, et al. Pharmacologic stress cardiovascular magnetic resonance in the pediatric population: a review of the literature, proposed protocol, and two examples in patients with Kawasaki disease [published online September 9, 2019]. Congenit Heart Dis. doi:10.1111/chd.12840