Coronary arterial size late after the atrial inversion procedure for transposition of the great arteries: Implications for the arterial switch operation

Background: Coronary flow reserve in the hypertrophied ventricle is reduced . One contributing factor may be the size of the proximal coronary arteries . In patients who undergo atrial inversion procedures for transposition of the great arteries, the left coronary artery supplies the pulmonary ventric le and may be smaller than the right coronary artery. We hypothesized that the dimensions of the coronary arteries may correlate with symptomatic stat us after atrial inversion and may be an important factor when these patient s are considered for the arterial switch operation. Methods: The proximal left and right coronary arteries were measured in 9 p atients with transposition and failure of the systemic right ventricle afte r atrial inversion, 10 asymptomatic patients after atrial inversion, and 10 patients with normal hearts. The diameters of the coronary arteries were i ndexed to body surface area and compared. Results: The absolute and indexed diameters of the right coronary artery we re greater in symptomatic patients than in asymptomatic patients (indexed: 3.1 +/- 0.6 vs 2.4 +/- 0.4 mm/m(2), P <.001) or control patients (2.0 +/- 0 .3, P <.001), and the absolute diameter of the left coronary artery was sma ller (2.9 +/- 0.7 vs 3.6 +/- 0.5 mm, P =.003 [asymptomatic], 3.6 +/- 0.5 mm , P = .01 [control]). In symptomatic patients, the absolute and indexed dia meters of the left coronary artery were smaller than those of the right (in dexed: 2.1 +/- 0.6 vs 3.1 +/- 0.6 mm/m(2), P <.001). By contrast, there was no difference in asymptomatic patients (2.2 +/- 0.5 vs 2.4 +/- 0.4 mm/m(2) , P = .44), and the left coronary artery was larger in normal control patie nts (2.2 +/- 0.4 vs 2.0 +/- 0.3 mm/m(2), P <.001). Conclusions: Differences in the sizes of the proximal coronary arteries may be related to symptomatic status in patients with transposition of the gre at arteries who have undergone an atrial inversion procedure, as well as to the efficacy of ventricular retraining. When pulmonary artery banding and subsequent arterial switch are considered for patients with a Mustard or Se nning procedure and a failing systemic right ventricle, the size of the pro ximal coronary arteries may be an important factor and should be evaluated with preoperative imaging studies.