Pulmonary regurgitation in transposition of the great arteries

Arterial Switch for Repair of Simple and Complex Transposition of Great Arteries in a New Unit

Between January 1987 and October 1992, 11 neonates and 2 infants (12 males and 1 female) underwent arterial switch operation (ASO). There were 9 simple transpositions of great arteries (TGA), 3 TGA with ventricular septal defect (VSD), and 1 double outlet of right ventricle (Taussig-Bing) with TGA. There were 12 cases of patent ductus arteriosus (PDA) and 6 cases of atrial septal defect (ASD). Nine patients had Yacoub type A coronary pattern, 3 had type B, and 1 had type D. The neonates' mean age was 15.5 days (one 120 days old and one 22 months old). The average body weight of the neonates was 4.2 kg. The Lecompte maneuver was performed on all patients. The average bypass time was 187.8 min, and mean aortic cross-clamp time was 76.2 min, with a mean circulatory arrest time of 10 min in 6 cases. Early hospital mortality was 15.4% (2 deaths)—1 patient died during operation from myocardial infarction, and another died postoperatively from poor heart function. All survivors experienced early postoperative heart failure and needed temporary inotropic support. One patient was lost to follow-up. The other 10 patients were free from any cardiac symptoms at follow-up, with good left ventricular function. Mild to moderate aortic regurgitation and stenosis and the same in the pulmonary valve were seen on echocardiogram. Seventeen months after ASO, 1 patient required reoperation for severe postoperative pulmonary stenosis. We concluded that ASO can be performed with an acceptable mortality rate in a new unit with no previous experience of such surgery.

Results of the arterial switch operation for transposition of the great arteries with ventricular septal defect. Surgical considerations and midterm follow-up data

Between January 1983 and December 1987, 62 patients underwent an arterial switch operation for transposition of the great arteries with ventricular septal defect or double outlet right or left ventricle. There were three hospital deaths (4.8%), and no deaths occurred in neonates (less than 1 month of age, n = 18). There were three late deaths, one due to coronary obstruction and two due to pulmonary vascular obstructive disease. One child has been lost to follow-up. We have prospectively evaluated the remaining 55 survivors by clinical evaluation, echocardiography, cardiac catheterization, ambulatory electrocardiographic monitoring, and limited electrophysiologic studies. The mean length of follow-up has been 27 +/- 16 months since surgery. One child has required reoperation for a residual ventricular septal defect; no child has undergone reoperation for supravalvar pulmonary or aortic stenosis. Aortic regurgitation was identified in 12 children (22%), which was mild in 11 and moderate in one. One child has asymptomatic occlusion of the left main coronary artery, one child has a tiny right coronary artery-to-pulmonary artery fistula, and one child has abnormal left ventricular wall motion according to follow-up angiography. No other abnormalities of systemic (left) ventricular function have been identified at late follow-up. In addition to the two late deaths due to pulmonary vascular obstructive disease, three children, all of whom were repaired at more than 6 months of age, have elevated pulmonary vascular resistance. Notable postoperative arrhythmias include complete heart block in four patients and nonsustained supraventricular or ventricular tachycardia early after surgery in eight patients (all resolved without medication at later follow-up). Only two patients have evidence of sinus node dysfunction and have not required treatment. The low hospital mortality and encouraging early follow-up data represent a significant improvement over atrial level repairs, supporting the arterial switch operation as the procedure of choice for children who have transposition of the great arteries with ventricular septal defect or double outlet ventricle. Because of the potential for the development of early pulmonary vascular obstructive disease in these patients, repair is recommended within the first 2 months of life.

A quantitative evaluation of aortic regurgitation after anatomic correction of transposition of the great arteries

Twenty patients who had undergone anatomic correction of transposition of the great arteries were assessed by Doppler echocardiography or cardiac catheterization, or both, to identify the presence of aortic regurgitation. The severity of aortic regurgitation was evaluated by radionuclide angiographic measurement of the stroke volume index a mean of 47.1 months postoperatively. The stroke volume index was defined as the ratio of the stroke counts between the left and right ventricles. A value greater than 1.8 was considered to indicate significant left ventricular volume overload. Eight patients (40%) were shown to have various degrees of aortic regurgitation by Doppler echocardiography or cardiac catheterization, or both. The mean (+/- SD) stroke volume index was 1.03 +/- 0.15 in these patients and 1.01 +/- 0.21 in the 12 patients without aortic regurgitation (p = NS). The stroke volume index was not above the normal range in any patient, indicating that the degree of aortic regurgitation present was trivial. This medium-term study indicates that trivial or mild aortic regurgitation is a frequent finding after anatomic correction of transposition of the great arteries. However, it rarely results in an audible cardiac murmur or significant left ventricular volume overload. Long-term evaluation is required to determine its importance.

Neonatal anatomical correction of transposition of the great arteries: non-invasive assessment of haemodynamic function up to four years after operation

Intracardiac and great artery blood flow velocities were recorded by pulsed and continuous wave Doppler ultrasound in 18 children aged between eight months and four years (mean 25 months) who had undergone anatomical correction of transposition of the great arteries in the first month of life. Postoperative peak flow velocities across the mitral valve and in the ascending aorta were not significantly different from those in an age matched control population, but tricuspid flow velocities were higher than normal. Aortic regurgitation was detected in only one of the eighteen patients, a markedly lower frequency than that reported after two stage anatomical correction. Peak velocities in the pulmonary artery were higher than normal, and in most cases there was some degree of stenosis of the pulmonary artery at the site of anastomosis.

Doppler echocardiographic comparison of haemodynamic results of one- and two-stage anatomic correction of complete transposition

Eighteen children who had single-stage and 18 who had two-stage anatomic correction of complete transposition between the ages of 1 week and 3 years (mean 6.5 months) were investigated with pulsed and continuous wave Doppler ultrasound. Peak mitral flow velocities showed no significant difference from normal after single-stage correction, but were significantly higher than normal after two-stage correction (P less than 0.05). Peak tricuspid flow velocities were significantly higher than normal in both groups (P less than 0.02 and P less than 0.001). There was no significant difference in pulmonary artery flow velocities between the two groups, which were means (SD) of 214 (84) cm/sec after single-stage and 179 (87) cm/sec after two-stage repair. Peak velocities in the ascending aorta were within normal limits after single-stage correction, but were lower than normal in the two-stage group (P less than 0.02). Mild aortic regurgitation was detected in 22% of single-stage and 55% of two-stage patients (P = 0.043, 2P = 0.085). Both types of repair are associated with higher peak tricuspid flow velocities than normal and have a similar incidence of mild supravalvar pulmonary stenosis. Mitral flow velocities are higher than normal only after two-stage correction. Velocities in the ascending aorta are lower than normal and the incidence of mild aortic regurgitation appears to be increased after two-stage repair, probably due to dilatation of the aortic root following banding of the pulmonary trunk.