Stroke and the Fontan Procedure

Abstract

The article by Day et al. [1] regarding stroke after the Fontan operation is important because it once again emphasized the clinical relevance of neurologic long-term outcome in children operated on for congenital heart diseases and the risk of disabling complications. We would like to add some comments. The authors reported a prevalence of about 11% of stroke in children with Fontan-type circulation. These figures are in an intermediate position between those previously reported by Mathews et al. (16%) and by us (3.6%) [2, 3].Day et al. were not able to identify a common risk factor, although a residual right-to-left shunt was detected in seven of eight patients. Probably other risk factors were the alveolar hypoxia and the increased pulmonary vascular resistance due to the higher altitude. However, stroke occurred even at sea level and in patients without communications between the ''right'' and ''left'' circulations. Reported patients with cerebrovascular events are few, which probably does not allow identification of definite risk factors. Indeed, it seems that we should probably search for factors other than the coagulation status and hemoglobin level.Microcytic erythrocytes are less elastic and less able to modify their shape to ''slip'' into the capillaries. Polycythemia secondary to hypoxia is commonly associated with a reduction of iron stores and microcytosis. Moreover, a long-standing cyanotic stimulus may have induced anatomic changes of small cerebral vessels, where the blood flow velocity may be further reduced. In this respect, the age at operation, iron status, and a microcytic anemia may be significant factors, because the longer the cyanotic stimulus, the higher is the risk for these alterations [3]. Unfortunately, Day and colleagues do not provide this information.Although the improvement in the general pediatric care of these patients and the tendency to operate on them at an earlier age could have reduced the impact of these factors, we believe that these complications are not so uncommon and are generally unreported. The availability of reliable data about the incidence and the patients' clinical characteristics may be helpful for understanding the pathogenesis of these disturbing complications. It could be the time to plan a multicenter study. References1. Day RW, Boyer RS, Tait VF, Ruttenberg HD (1995) Factors associated with stroke following the Fontan procedure. Pediatr Cardiol 16:270-275 2. Mathews K, Bale JF Jr, Clark EB, Marvin WJ Jr, Doty DB (1986) Cerebral infarction complication Fontan surgery for cyanotic congenital heart disease. Pediatr Cardiol 7:161-166 3. Rosti L, Cerini E, Frigiola A (1995) Cerebral infarction after Fontan procedure for tricuspid atresia. Cardiol Young 5:357-359

Intracardiac thrombus formation after the Fontan operation

“…The symptoms of thrombus formation include venous obstruction, progressive cyanosis, paradoxic emboli to the cerebral or peripheral circulation (if right-to-left atrial shunt is present), or atrial tachyarrhythmia. [13][14][15] One of our patients had a history of pulmonary embolization, and 3 others had a history of systemic or cerebrovascular embolization. The source of thromboembolism remained unknown, but cardiac anatomy was not investigated by TEE at that time.…”

Pediatric cardiovascular disease and stroke

“…In essence, the Fontan procedure redirects venocaval blood directly to the pulmonary arteries separating systemic from pulmonary venous blood [37]. Stroke following the Fontan procedure has been reported in 1.4%-16% of children [18,[37][38][39][40][41][42][43][44]. This may occur in the immediate post-operative period [18,38,42,45] but has been described as long as 5-9 years following surgery [42,46,47].…”