Outcomes in the short and long term
Despite the advances made in diagnosis and surgical treatment, the overall prognosis remains less than satisfactory in either the long or the short term.14-22 To an extent, this is hardly surprising, since right isomerism has long been recognized as one of the worst forms of congenital heart disease. The malformations in right isomerism, for the most part, preclude biventricular repair.15,18,19,21-23,41,43-47 Reported mortalities range between one-third and one-half for construction of a systemic-to-pulmonary arterial shunt and repair of totally anomalous pulmonary venous connection repair, while comparable mortalities have ranged between one-third and three-quarters for functionally univentricular repair.15-23,46 Of those in whom a superior cavopulmonary connection had been constructed, up to one-quarter proceeded to completion of the Fontan circulation, but even in this group there was reported mortality of one-fifth.15-23,42 Totally anomalous pulmonary venous connection was identified as a poor prognostic indicator, associated with a median age at death of of 3 months, with the addition of pulmonary atresia resulting in a median age at death of 1 month.9 But, since totally anomalous pulmonary venous connection is universally present in those with right isomerism, it is likely the combination with pulmonary atresia that is the straw that breaks the back of the camel.
Reported mortalities for those with left isomerism and functionally univentricular repair range between one-fifth and one-third, but for those suitable for biventricular repair, mortality has been reported between zero and one-quarter.16,17 Of those undergoing univentricular palliation, however, only seven-tenths are in NYHA class I, as opposed to almost all of those suitable for biventricular repair.15-23,55 Longer term prognosis at present is equally depressing. At one year, 85% of those with right isomerism are dead, along with more than half of those with left isomerism.15-23,55 The situation, of course, is further tilted against those with right isomerism, since in absence of the spleen they have an increased risk of sepsis.15-23,55-57 In most reported series, unsurprisingly, survival is better when the lesions permit biventricular repair.14-23,55-58 Such biventricular repair has been reported in a small proportion of patients with right isomerism.15,18,19,21-23,41,43,47-49 And for those not receiving surgical intervention, death is inevitable.28 Incremental risk factors for death have been identified as obstructed totally anomalous pulmonary venous connection, restenosis of pulmonary veins, and pulmonary atresia.