We read the article by Kim et al,1 which was recently published in Transplantation, with great interest. In the study, the authors found that HA flow lower than 400 mL/min was associated with an increased rate of biliary strictures in younger donors (<50 years) and in patients with duct-to-duct anastomoses (P = 0.028). Lower HA flow was also associated with decreased graft survival (P = 0.013). Nevertheless, only donor age and HCC as the primary diagnosis were related to biliary strictures in the first 24 months based on multivariate analysis. HA flow lower than 400 mL/min was associated with biliary strictures (hazard ratio, 1.53; 95% confidence interval, 1.04-2.24; P = 0.0297) but only in univariate and not multivariate analysis. In addition, HA flow lower than 400 mL/min was also related to graft failure in univariate analysis. The authors conclude that increasing HA flow in patients receiving grafts from younger donors and with low HA flows should be considered. Recently, we conducted a retrospective observational study over a prospective database analyzing 333 consecutive orthotopic liver transplants performed between January 2007 and October 2012. Two groups were established per HA flow (216 patients with HA flow <200 mL/min and 117 patients with HA flow ≥200 mL/min). Lower HA flow was significantly associated with female donors (37.6% vs 24.5%, P = 0.012) and with lower body weight (73.2 ± 11.8 vs 76.2 ± 12.4 kg, P = 0.011). No differences between groups were observed in recipient parameters. Longer intensive care unit and hospital stays after transplantation were observed in the lower-HA-flow group compared with the higher-HA-flow group: 5 versus 4 days (P = 0.03) and 20 versus 16 days (P = 0.004), respectively. No significant differences in vascular complication (9.4% vs 6.9%, P = 0.425) and biliary complication rate (12.8% vs 8.3%, P = 0.191) were found. Moreover, 5-year graft survival was comparable between both groups (70.8% vs 70.8%, P = 0.224). We also studied 100 mL/min as the HA flow threshold (12 patients with HA flow <100 mL/min and 321 patients with HA flow ≥100 mL/min). Significantly, lower graft survival was observed in the lower-HA-flow group at 5 years (54.6% vs 70.8%, P = 0.006), but no differences were found in arterial (8.3% vs 8.1%, P = 0.999) or biliary complications (8.3% vs 10%, P = 0.999). The lack of a direct relationship between HA flow and biliary complications has also been observed by Pratschke et al,2 who reported that HA flow under a cutoff point of 240 mL/min was related to impaired postoperative organ function and higher rates of primary nonfunction after liver transplantation. Moreover, lower HA flow was an independent factor of lower organ survival in univariate and multivariate analyses. Of note, biliary complications were not affected by HA flow in this study. In summary, recent studies have failed to define a threshold for HA flow that could be related to biliary complications after LT. Finally, we agree with the authors when they suggest that the relationship between biliary strictures and HA flow may be an association but not a causality.
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