The history of right heart bypass before Fontan.

Numerous clinical and experimental studies have suggested that adequate pulmonary blood flow and normal central venous pressure may be maintained without significant contribution of right ventricular function. These data induced experimental and clinical research in the quest for complete bypass of the right heart. More than 40 different operations have been designed to bypass the right ventricle. Partial right ventricular bypass was achieved in 1949 by anastomosing the superior vena cava to the pulmonary artery in animal experiments. In 1950 such as operation was successfully performed clinically for the first time. Complete bypass of the right heart was accomplished for the first time experimentally in 1954 by performing a superior vena cava-to-right pulmonary artery anastomosis and implanting the inferior vena cava into the left atrium. Successful clinical bypass of the right heart was carried out later by implanting both vena cavae into the pulmonary circulation. Until the cavopulmonary shunt conclusively proved the validity of the concept that compensated circulation is possible without participation of the right ventricle, surgeons did not fully understand its possible relevance in clinical situations. The development of partial and complete right heart bypass procedures, both experimental and clinical, not only presented us with viable alternatives to aortopulmonary shunts like the Blalock-Taussig or Potts anastomosis, but it also opened the way to development of new operations such as the Fontan procedure which are based on the principle of low pressure pulmonary flow and right ventricular bypass.