In this retrospective observational study, the Authors aimed to evaluate incidence, risk factors, temporal course of hemodynamic recovery, and impact on functional graft outcome of post reperfusion syndrome (PRS) in a large sample of patients undergoing cadaveric donor orthotopic liver transplantation (OLT). In multivariate analysis they found that higher donor age, higher donor risk index (DRI) and lower central venous pressure (CVP) before graft reperfusion were independent risk factors for PRS in multivariable analysis. Hemodynamic changes following portal vein reperfusion were divided into 3 phases and the Authors identified a negative correlation between DRI and the slope of hemodynamic recovery following hepatic artery reperfusion. Finally the Authors found no significant differences between the need for hemodynamic support with catecholamines in patients developing and non developing PRS; moreover, the appearance of PRS didn’t have any effect on graft survival, rejection graft free survival, post transplant recovery of liver enzymes and early allograft dysfunction. The subject of this manuscript is very interesting because, since PRS is a serious intraoperative event with a still unclear etiology, the evaluation of potential risk factors could define prevention strategies and foster perioperative management of liver transplant recipients. This is the largest study evaluating incidence and risk factors for PRS until now. In my opinion this paper is very well written, the abstract is clear and accurately synthesizes the rest of the article, title is informative and precise. The introduction section is rather short but clearly frames the topic of the article. The Methods section is clear, subject selection criteria are defined and their flow through the study is well defined. The study design is appropriate to answer the aims of the study, the statistical analysis used goes beyond my statistical knowledge so I can’t evaluate it. The results section correctly informs the reader of the main results of the study, tables are well presented and figures are self explaining. The discussion section answers the aims of the study, describes study limitations and contains opportunities for future research such as the evaluation of other preload assessment methods in order to prevent PRS. Overall, I think that this is an very interesting work, I failed to find any major flaw, I just will give some minor suggestions:

1. Since PRS is often reported to have effects on postoperative kidney function and mortality, it would have been interesting to show these data.

2. In the “Independent predictors of PRS” section, the Authors state that “The results of univariate and multivariate regression analyses of each variable studied are summarized in Tables 1 and 2” this is not correct since table 1 only describes the study population while table 2 contains both univariate and multivariate analysis results.