Adenosine stress myocardial perfusion scintigraphy in pediatric patients after arterial switch operation

Feasibility and Utility of Adenosine Stress Echocardiography in Children Following Post-Arterial Switch Operation: A Comparison with Technetium 99m-Sestamibi Myocardial Perfusion SPECT (MPS)

There is a need for a sensitive, safe, and cost-effective tool for coronary assessment among asymptomatic post-operative children who have undergone arterial switch operation (ASO) for transposition of great arteries (TGA). Adenosine stress echocardiography may be useful in assessing major structures as well for coronary functional assessment. Twenty-six children [median age 6.0 years; IQR 4.9-7.1 years, (22 boys)], who had undergone ASO at a median age of 40 days (IQR 30-75 days), were prospectively included. Left ventricular ejection fraction (LVEF) was calculated in both rest and stress studies (140 µg/kg/min of adenosine IV over 4 min), along with assessment of regional myocardial wall motion. Coronary flow reserve (CFR) was also measured in the left anterior descending artery (LAD). Technetium 99m-MIBI [0.2mCi/kg] was injected after 2 min of adenosine infusion. Adenosine infusion had to be stopped in two children, due to transient atrioventricular (AV) block. The LVEF increased from 55.87 ± 7.27 to 61.20 ± 7.70% (p  < 0.001) with adenosine stress. No significant regional wall motion abnormality was seen in rest or stress. Distal LAD could not be visualized in four patients. Basal and peak coronary flow velocities were 41.51 ± 14.12 and 74.18 ± 6.01 cm/s. Mean CFR was 1.91 ± 0.51. Myocardial perfusion scintigraphy (MPS) was normal in all the patients. Four patients were lost to follow-up and remaining children did not develop any adverse events in the follow-up period of 64.5 ± 7.19 months. Adenosine stress echocardiography is feasible as the initial screening test in the assessment of asymptomatic post-operative children with ASO, at minimal to no inconvenience to the patient. The findings concurred with stress MPS.

Long-Term Results of Bay Window Technique for Coronary Translocation in the Arterial Switch Operation

BACKGROUND

Accurate coronary translocation is very important for a successful arterial switch operation (ASO) for transposition of the great arteries (TGA) and to provide good long-term outcomes. We have previously reported the "bay window" technique as a useful option for coronary translocation with excellent midterm results. However, the long-term results of this technique and the morphological changes in the coronary channel have not yet been reported.

PATIENTS AND METHODS

Between September 2001 and December 2012, 33 patients with TGA underwent coronary translocation using the bay window technique concomitantly with ASO. The diagnoses were TGA with intact ventricular septum in 21, TGA with ventricular septal defect in 7, and Taussig-Bing anomaly in 5. The median age of the patients at operation was 12 days, and their median body weight was 2.93 kg. Coronary artery patterns were as follows: Shaher and Puddu's type 1 in 23, single coronary artery in 4, intramural type in 1, and others in 5.

RESULTS

The median follow-up period was 4.5 years. There were no operative deaths, but there was one late death because of sepsis 13 months after ASO. Coronary artery evaluation with angiography, computed tomography, or myocardial scintigraphy was performed in 22 patients. There was no abnormal coronary morphology or perfusion. Coronary channel dilatation was not observed. Three patients underwent reoperation for pulmonary stenosis.

CONCLUSIONS

The bay window technique provides excellent long-term results in ASO for TGA. Three-dimensional computed tomography revealed no aneurysmal changes in the bay window channel at nine-year follow-up examination.

Myocardial perfusion SPECT in a case of retropulmonary looping of left coronary artery in a baby after arterial switch surgery

Pediatric myocardial perfusion imaging (MPI) is not a routine investigation in an Indian setting due to under referrals and logistic problems. However, MPI is a frequently performed and established modality of investigation in adults for the identification of myocardial ischemia and viability. We report myocardial perfusion scintigraphy in a case of retropulmonary looping of left coronary artery in a baby after arterial switch surgery. Adenosine stress MPI revealed a large infarct involving anterior segment with moderate reversible ischemia of the lateral left ventricular segment. Coronary angiogram later confirmed left main coronary artery ostial occlusion with retrograde collateral supply from dilated right coronary artery.