Hepatobiliary Scintigraphy in ALPPS: A Response
We thank de Santibanes et al1 for their relevant comments on our article2 that assessed the future remnant liver (FRL) function in the inter-stages period of Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy using sequential (99m)Tc-mebrofenin hepatobiliary scintigraphy (HBS) with single photon emission computed tomography (SPECT). Considering the high morbi-mortality rates (including early liver failure), we assumed that the changes in liver volumes were not paralleled by proportional functional changes. Indeed, in 5 patients undergoing ALPPS, we observed (1) a drop of total liver function due to a loss of function in the excluded liver that was sharper than the functional gain in the FRL, (2) a functional gain in the FRL that was constantly lower than the volume gain. This resulted in poststage 1 liver failure in 1 elderly, leading to poststage 2 death despite a significant volumetric gain. Thus, as underlined by de Santibanes et al, “even though FRL volume is still the gold standard for defining FRL sufficiency, this does not seem to be the case for inter-stages FRL evaluation in ALPPS.”
As stated by de Santibanes et al,1 the use of HBS for assessing the inter-stages FRL function in ALPPS patients has already been reported before, though in an anecdotic manner in 2 reports3 that did not focus on HBS, meaning that the reader had to screen the whole article to find 1 succinct HBS result for 1 single patient. The function of the FRL that was given only as a percentage of the total functioning liver represented up to 40% of total liver function, allowing a safe ALPPS stage 2. Following these reassuring data, HBS was not routinely performed in most ALPPS centers. By contrast, our study provided for the first time a precise analysis of the segmental hepatic function, analyzing separately the function within the excluded segments and the FRL. This was also the first time that HBS was performed sequentially both before stage 1 and stage 2 allowing specific analysis of the inter-stages kinetic of FRL function in parallel with volume. This robust methodology allowed us to draw the clear conclusion that evaluating the FRL volume alone is not appropriate and that HBS should be systematically performed.
Regarding the second point underlined by de Santibañes’ team, we indeed “confirm using HBS that the excluded liver segments … works as an auxiliary liver until its removal”… knowing that the verb “confirm” (ie, “to give approval to”) means that similar observations were indeed made before. On the contrary, rather than confirming this established phenomenon, we aimed to warn surgeons about the drop of total liver function and the delayed functional gain in the FRL, which was on average 2-fold lower than its volumetric gain. This message of caution was important to give to surgeons likely to perform ALPPS. This may indeed explain why “the one-week interval dogma has been penalized in several series with high complication rates and mortality, despite all patients were operated with a theoretically sufficient FRL,” as indicated by de Santibanes et al.1
Third, we did not contrast our results with those of Tanaka et al,4 as we felt that both the objectives and methodologies of each study deeply differed. First, Tanaka et al4 used 99mTc-galactosyl human serum albumin HBS, and not mebrofenin HBS. Second, the authors aimed to compare ALPPS 1 week after the stage 1 with classical 2-stage hepatectomy 3 weeks after the stage 1, whereas we focused on ALPPS before and after the stage 1.