Otsuka M, Kodama Y, Kuraoka A, Ishikawa Y, Nakamura M, Nakano T, Kado H, Umemoto S, Ishikita A, Sakamoto I, Ide T, Tsutsui H, Sagawa K.Pediatr Cardiol. 2022 Feb;43(2):360-365. doi: 10.1007/s00246-021-02727-6. Epub 2021 Sep 8.PMID: 34498105
Take Home Points:
Higher mortality rates have been reported for patients with Down’s syndrome undergoing Fontan surgery compared to patients with non- Down’s syndrome patients. The causes of death are diverse, but pulmonary vascular obstructive disease is considered a contributing factor. In the study, they observed only one death, but there was a significant upward trend in central venous pressure in post-Fontan patients with Down’s syndrome. Post-Fontan patients with Down’s syndrome must be managed carefully, with regular evaluation for central venous pressure by cardiac catheterization.
Commentary from Dr. Masamichi Ono (Munich, Germany), section editor of Congenital Heart Surgery Journal Watch:
In this study, results after the Fontan procedure was compared between 7 patients with Down’s syndrome and 35 patients with non-Down’s syndrome. Main diagnosis of Down’s syndrome was unbalanced AVSD in 6 patients and tricuspid atresia in 1 patient. There was 1 death in patients with Down’s syndrome. The patients died of pulmonary thrombosis. At the last follow-up of median 19 years, creatinine, AST, ALT concentrations were significantly higher in the patients with Down’s syndrome. There was no significant difference in medications except for the administration of pulmonary arterial hypertension-specifc therapies.
Postoperative cardiac catheterization data showed that central venous pressure, transpulmonray gradient, and pulmonary artery wedge pressure increased in patients with Down’s syndrome, whereas these variables did not changed in patients with non- Down’s syndrome. Arterial oxygen saturation decreased in patients with Down’s syndrome, whereas it did not changed in patients with non- Down’s syndrome.
The main significance of the study are that, there was a significant increase in central venous pressure and trans-pulmonary pressure gradient over time after the Fontan procedure in patients with Down’s syndrome compared with patients with non-Down’s syndrome. Whereas, there was no statistically significant difference in the change in calculated RpI over time.
Patients with genetic anomalies including Down’s syndrome are generally regarded as not being good candidates for the Fontan procedure. Although exact mechanisms are not still clear, we observe failing cavopulmonary shunt physiology more frequently in patients with genetic anomalies, compared with patients without genetic anomalies. As the causes, pulmonary vascular abnormalities in patients with genetic anomalies are speculated. It might not be apparent before bidirectional cavopulmonary shunt (BCOS) procedure, but emerged postoperatively as a failing BCPS physiology. Even after the Fontan completion, increase of central venous pressure and transpulmonary gradient in patients with Down’s syndrome was reported in this study. Special attentions should be paid for patients with Down’s syndrome, in respect to indication of BCPS procedure, postoperative management, and even after the Fontan completion.
As for the therapy, multiple classes of PAH-ST have been reported to reduce central venous pressure, reduce pulmonary vascular resistance, and increase exercise tolerance in Fontan patients. In this study, catheterization data before and after administering PAH-ST were obtained from 2 patients in the Down’s syndrome group. In both patients, central venous pressure and transpulmonary pressure gradient decreased, which may be caused by macitentan as a PAH-ST. However, further studies are needed to determine the benefit of PAH-ST in Fontan patients with Down’s syndrome.
In summary, central venous pressure tended to increase over time in patients with Down’s syndrome after Fontan procedures compared with patients with non-Down’s syndrome. Further research is warranted to clarify better management in patients with Down’s syndrome after the Fontan procedure, including the efficacy of pulmonary arterial hypertension-specifc therapy.