Neoaortic root dilation and neoaortic valve regurgitation are common complications in infants with transposition of the great arteries who undergo an arterial switch operation for repair, and the risk of developing these changes in the neoaorta increases over time, according to the results of a retrospective database study of patients at Children’s Hospital of Wisconsin.
In addition, when dilation occurs, the dimensions may progressively enlarge over time, making it important to maintain lifelong surveillance of this population, according to a report published the Annals of Thoracic Surgery.
Although perioperative mortality and long-term survival (assessed up to 30 years) has improved in more recent eras for use of an arterial switch operation (ASO) for transposition of the great arteries (TGA), these long-term studies have also shown important late complications that may contribute to late morbidity and the need for reoperation, according to Dr. Jennifer G. Co-Vu and her colleagues at the Medical College of Wisconsin, Milwaukee.
These complications include coronary artery insufficiency, right ventricular outflow tract obstructions, and problems with the native pulmonary root and the pulmonary valve functioning as the neoaortic root and the neoaortic valve, respectively. Dr. Co-Vu and her colleagues performed their study to determine the prevalence of neoaortic root dilation and neoaortic valve regurgitation in patients treated at their institution and to determine risk factors involved in the development of these late complications.
Out of 247 patients with TGA treated with an ASO at the hospital, there were 124 patients who had at least one available postoperative transthoracic echocardiogram at least 1 year after the ASO. Median age of these patients was 0.2 months at the time of their ASO and 7.2 years at their last follow-up; 71% were boys (Ann. Thorac. Surg. 2013;95:1654-9).
Retrospective measurements of the neoaortic annulus and root were performed on all available transthoracic echocardiograms and the severity of neoaortic valve regurgitation was determined by assessing the width of the color Doppler jet of regurgitation measured at the level of the valve in the parasternal long-axis view. A jet width of 1-4 mm was defined as trivial to mild; 4-6 mm was defined as moderate; and greater than 6 mm indicated severe regurgitation, according to the researchers. Significant regurgitation was defined as moderate or severe. Significant neoaortic annulus dilation was defined as a z score of 2.5 or greater.
They evaluated potential risk factors for the development of neoaortic root dilation, annulus dilation, and neoaortic valve regurgitation, including age at ASO, sex, weight, coexisting lesions, prior interventions, and associated operations with the ASO. Coexisting lesions and prior interventions occurred in nearly 60% of the patients. The most common previous intervention was balloon atrial septostomy (54%).
Significant neoaortic root dilation developed in 88 of 124 (66%) of the patients during follow-up, with the probability of being free from a root diameter z score of 2.5 or greater of 84%, 67%, 47% and 32% at 1, 5, 10, and 15 years, respectively. Significant risk factors predicting neoaortic root dilation using multivariate analysis were a history of double outlet right ventricle (DORV), previous pulmonary artery (PA) banding, and length of follow-up. A history of ventricular septal defect (VSD), coarctation, left ventricular outflow tract obstruction, and age at ASO were not significant risk factors.
Significant annulus dilation occurred in 54% of patients, with significant risk factors including a history of VSD, history of DORV, and the presence of a dilated neoaortic root. History of PA banding and length of follow-up were not significant.
Moderate or severe neoaortic valve regurgitation occurred in 17 of 124 (14%) of the patients, with a probability of being free of these levels of regurgitation of 96%, 92%, 89%, and 75% at 1, 5, 10, and 15 years, respectively. The significant risk factors for regurgitation were history of DORV, VSD, left ventricular outflow tract obstruction, and length of follow-up.
No patient in the series reported by the researchers required reintervention on the neoaorta.
Limitations of the study included its retrospective nature; the lack of postoperative echocardiograms on all patients, which raises questions of selection bias; and an inability to account for changes in surgical and postoperative management over time, the authors noted.
"Neoaortic root dilation and neoaortic valve regurgitation are common complications in patients with TGA after repair with ASO. Patients with DORV morphologies or previous PA banding may be at higher risk for these complications," the researchers concluded.
The authors had no relevant disclosures.