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With the introduction of cyclosporine in 1969, survival rates after liver transplantation (LT) improved drastically;1 however, mortality still remained high due to challenges encountered during the anhepatic phase when the inferior vena cava (IVC) is first clamped and subsequently removed, along with the diseased liver. Together with the interruption of the portal venous blood flow, there is a dramatic decrease in the volume of the central venous return to the heart, which in turn, decreases the cardiac output and arterial pressure. Furthermore, when these events occur with the backdrop of hypoperfusion of critical organs and extensive bleeding from venous collaterals, the consequences can have disastrous implications. Additionally, a systemic increase in potassium levels and acidosis usually occur during reperfusion of the liver graft.2,3
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Pros and Cons of Venovenous Bypass
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In 1984, Griffith et al.4 described a new technique for overcoming these challenges. The venovenous bypass (VVB), which is performed with a temporary femoral-to-jugular venovenous pump-driven bypass system, was introduced to LT to maintain the venous return to the heart. The use of the VVB increases cardiovascular stability during the anhepatic phase, but has a complication rate of 10% to 30% and generally leads to both prolonged operation and warm ischemia times (Table 61-1).2,4,5
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DEVELOPMENT OF THE PIGGYBACK TECHNIQUE
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The piggyback method was first described by Calne et al.6 but was popularized during a clinical study conducted by Tzakis et al. in 1984.7 This technique circumvents the need for a pump-driven VVB and ensures that the venous return remains intact during the whole LT procedure, which ultimately leads to increased hemodynamic stability in recipients. Moreover, fewer anastomoses are needed in this procedure, resulting in an overall reduction in the duration of the anhepatic phase, as well as a decrease in the length of time for both warm ischemia and the operation duration (Table 61-2).
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