BACKGROUND: Transposition of the great arteries accounts for 5% to 7% of all congenital heart disease. It is the most common cyanotic heart disease and the most frequently diagnosed in the neonatal period. Arterial switch operation is the procedure of choice in patients with transposition of the great arteries. The purpose of this study is to identify variables that will undergo this procedure in patients.
MATERIALS AND METHODS: This is a cross-sectional study involving 77 patients who underwent arterial switch operation from January 1991 to June 1992 at The Philippine Heart Center. Primary outcome measured was mortality. Patients were also classified into: transposition of the great arteries, transposition of the great arteries with intact ventricular septum, transposition of the great arteries with ventricular septal defect, and transposition of the great arteries with left ventricular outflow tract obstruction.
RESULTS: Predictors of mortality were identified in patients who underwent arterial switch operation. Statistically significant pre-operative variable were pulmonary artery pressure and aorta: pulmonary artery annulus ratio; operative variable was bypass time and post-operative predictors were use of dobutamine (p=0.024), presence of acidosis (p=0.001) and bleeding (p=0.008). A clinical scoring index was formulated to predict outcome in patients who will undergo arterial switch operation. Variables included in the scoring system were sex (4.2125), left ventricular posterior wall thickness (3.7079) and aorta: pulmonary artery annulus ratio (4.6068) based on the result of multiple regression analysis. In the clinical scoring index developed, the cut off score was at eight, which has 37% sensitivity and 97% specificity for predicting mortality. At a score of 4-5; sensitivity is at 79%-58% and specificity of 54%-79%, and mortalit is probable. At a score of 9-13; sensitivity is at 3%-29%, specificity is 100%, and mortality is definite.
CONCLUSION: This study was able to identify predictors of mortality and developed a scoring index that will predict outcome in patients with transposition of the great arteries who will undergo arterial switch operation.