進化する右心バイパス循環

Since Fontan’s exploit over 30 years ago, a number of important advances relevant tothe Fontan strategy could be achieved as being variations in the technique of anatomical connectionof the systemic venous circulation to the pulmonary arteries and variations instaging of the Fontan procedure. Innovative Norwood procedure and its concept as a firststage of palliation to Fontan circulation have been equivalent to Fontan’s exploit, and haveproduced the “current” philosophy of pushing patients into Fontan physiology early in lifewith hemi-Fontan procedure or bidirectional Glenn shunt.The aim of the first half of our present study is to determine the optimal size and techniquefor construction of the systemic-to-pulmonary arterial shunt which will provide suitablepulmonary blood flow in first-stage Norwood palliation for hypoplastic left heart syndromein neonates. A prosthesis of 3.0 or 3.5 mm in diameter arising from the brachiocephalicartery would be acceptable and can be recommended for first-stage Norwood palliation insmall infants. Although many complicated factors are concerned in the regulation of pulmonaryblood flow, the fundamental strategy is to create a necessary and minimal systemicto-pulmonary arterial shunt in the first-stage Norwood palliation, and then to proceed swiftlywith a second-stage hemi-Fontan procedure.It remains to be determined whether all children should undergo an intermediate hemi-Fontan procedure or bidirectional Glenn shunt prior to their Fontan completion. In my personalopinion, the several advantages of the hemi-Fontan procedure seem to be weighed againstits disadvantages. It is our current practice to perform an intermediate hemi-Fontanprocedure in staging of the Fontan strategy of the patients with some risk factors. Althoughwe generally have waited 6-8 months after a hemi-Fontan operation for a Fontancompletion, we would like to perform an early Fontan completion a few months after hemi-Fontan procedure to shorten the period of partial Fontan circulation and get nearly normaloxygen saturation. Careful follow-up and further investigation will be necessary to determinethe most optimal management guidelines for the Fontan circulation.