LONG-TERM HEMATOLOGICAL MANAGEMENT OF CYANOTIC CONGENITAL HEART-DISEASE

The long-term management of cyanotic congenital heart disease requires treatment of raised haematocrit (> 65 %) whilst conserving the quality of the red blood cells [mean corpuscular volume, mean corpuscular haemoglobin concentration (MCHC)]. Since 1975, the author has chosen chemotherapy (hydroxyurea, pipobroman) as first-line treatment, reserving iron supplements, phlebotomy and platelet antagonists as adjuvant therapy. Pre-treatment data of 170 patients showed: a high prevalence of hypochromic microcytosis due to iron deficiency and of thrombopaenia, in relation to the severity and duration of the polycythaemia. Hyperuricaemia was greater than 420 mu mol/l in 67 % of cases; effort tolerance and hyperviscosity were related to the haematocrit and iron deficiency. One hundred and forty seven patients were followed up for a total duration of 769 years of chemotherapy: Clinical tolerance was good: biological tolerance was marked by a high frequency of thrombocytopaenia requiring withdrawal (10 cases) or reduction of treatment (34 cases). The causes of the 39 deaths observed are analysed : none was related to the hydroxyurea or pipobroman. The treatment or follow-up was stopped in 29 cases : the reasons are reported. Seventy eight patients under treatment had a favourable outcome with normal social reinsertion in 74 cases. This efficiency was related to maintenance of a haematocrit < 65 %, to correction of the iron deficiency and increase in the MCHC. These results were obtained with an average dosage of 19 +/- 14.5 mg/kg/day of hydroxyurea (69 patients). By slowing erythropoiesis, chemotherapy reduces the indication of phlebotomy, so reducing iron loss : it also inhibits excessive bouts of polycythaemia in cases of iron therapy. Early treatment before the haematocrit reaches 65 %, reduces the frequency of thrombocytopaenia. The role of platelets in the pathogenesis of cerebral and pulmonary infarction is discussed and their responsibility in the evolution of Eisenmenger' s syndrome; theoretically, it justifies the use of platelet antiaggregants from childhood.