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Assessing the results of surgery for congenital heart disease: a continuing process.

THE SURGICAL TREATMENT of most forms of congenital heart disease is a remarkable success story. Mortality figures are low even for complex conditions such as transposition of the great arteries and tetralogy of Fallot. Despite the immediate operative success, however, important residua, sequelae and late complications have been reported in the more common conditions (table 1). In this issue of Circulation, the University of Minnesota pediatric and adult cardiology groups add another chapter to reports of abnormalities after surgery for congenital heart disease.1 They investigated 11 survivors of the Fontan procedure for treatment of tricuspid atresia. Their report illustrates three recurring themes in follow-up studies for postoperative congenital heart disease patients. First, the surgical mortality is very low, with no perioperative deaths in their 16 consecutive patients. Second, clinical assessment of cardiac status (New York Heart Association classification) reveals that most patients are asymptomatic -nine of 13 (69%) in their series or have only minimal symptoms. Third, with continued follow-up and postoperative investigations, significant residua, sequelae and complications become apparent (table 2). Of particular interest are the late deaths (two of 16 died suddenly, suggesting dysrhythmia), the low cardiac index at rest, and the abnormal response to exercise. Although the numbers of patients are small, the message seems clear: In this group of postsurgical patients, cardiac performance is suboptimal and the incidence of sudden death (possibly due to dysrhythmia) is high. These latter problems (dysrhythmia and abnormal cardiac performance) apply to postoperative tetralogy and transposition patients and suggest that similar mechanisms may play a role in such abnormalities in these cyanotic patient groups (table 3). How do the data regarding the Fontan operation guide the physician attempting to provide optimal care to his or her patient with tricuspid atresia? As with most therapy for complex congenital heart disease, the answers are not clear. In certain subsets of patients, particularly those who fulfill Fontan's criteria for an optimal candidate for his procedure,2 the postoperative results appear to be good.3 8 These ideal patients, however, would probably also do excep-