Echocardiographic evaluation of left ventricular outflow tract obstruction in complete transposition of the great arteries

Coronary echocardiography in 406 patients with d-loop transposition of the great arteries

OBJECTIVES

The reliability of two-dimensional echocardiography for determining the proximal coronary artery anatomy in d-loop transposition of the great arteries was investigated in 406 infants who underwent surgical repair at one institution.

BACKGROUND

The origin and proximal course of the main coronary arteries can affect the surgical results of the arterial switch operation. Preoperative determination of the coronary artery anatomy appears to be advantageous for the surgeon.

METHODS

All infants with d-loop transposition who underwent a two-dimensional echocardiogram and primary surgical repair at our institution between 1987 and 1992 were identified, and the echocardiographic, operative and, when available, autopsy reports were reviewed for coronary artery anatomy, presence of a ventricular septal defect and the spatial relation between the arterial roots. The two-dimensional echocardiographic findings were compared with surgical or autopsy findings. The relation between proximal coronary artery anatomy and 1) a ventricular septal defect, and 2) the spatial orientation of the arterial roots was investigated. Twenty-seven infants diagnosed with an intramural coronary artery were not included because they are the subjects of another report.

RESULTS

Excluding intramural coronary artery patterns, 10 different types of coronary artery anatomy were seen in these 406 patients. The coronary arteries were imaged adequately in 387 (95%) of the 406 patients. The coronary artery anatomy was determined correctly by two-dimensional echocardiography in 369 (95.4%) of the 387 patients, with 18 errors in diagnosis. During the most recent 2.5 years, 193 (98.5%) of 196 patients were diagnosed correctly, with three diagnostic errors. Patients with a ventricular septal defect or side-by-side great arteries are more likely to have an unusual coronary pattern.

CONCLUSIONS

Echocardiography appears to be highly reliable for determining proximal coronary artery anatomy in d-loop transposition of the great arteries. An unusual coronary artery pattern is more likely in patients with side-by-side great arteries or posterior aorta or a ventricular septal defect, or both.

The diagnostic evaluation of patients with complete transposition

SummaryThe vast majority of patients with complete transposition present during either the neonatal period or early infancy. Almost always the diagnosis and the categorization of associated lesions can be established by cross-sectional echocardiography. Doppler techniques usually provide enough information about flows to allow palliative or radical surgery to be undertaken without formal cardiac catheterization, because balloon atrial septostomy is carried out with echocardiographic imaging, often on the intensive care unit. Angiography is occasionally performed to visualize the pulmonary arteries or the aorta, and, if there is suspicion of a significant elevation of the pulmonary vascular resistance, it must be measured at cardiac catheterization. Neither cross-sectional echocardiography nor aortography is entirely reliable in identifying those patterns of the coronary arteries which are a contraindication to the arterial switch operation. There is, as yet, no evidence that either magnetic resonance imaging or transesophageal echocardiography are superior to more conventional methods of preoperative diagnosis in complete transposition and it seems unlikely that they will be required.