Low Preoperative Platelet Count Predicts Risk of Subclinical Posthepatectomy Liver Failure in Right Lobe Donors for Liver Transplantation

Optimizing pre-donation physiologic evaluation for enhanced recovery after living liver donation - Systematic review and multidisciplinary expert panel recommendations

BACKGROUND

While preoperative physiologic evaluation of live liver donors is routinely performed to ensure donor safety and minimize complications, the optimal approach to this evaluation is unknown.

OBJECTIVES

We aim to identify predonation physiologic evaluation strategies to improve postoperative short-term outcomes, enhance donor's recovery, and reduce length of stay. We also aim to provide multidisciplinary expert panel recommendations.

DATA SOURCES

Ovid MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Central.

METHODS

The systematic review followed PRISMA guidelines, and the recommendations were formulated using GRADE approach and experts' opinion. The search included retrospective or prospective studies, describing outcomes of physiologic evaluation predonation. The outcomes of interest were length of stay, postoperative complications (POC), recovery after donation, and mortality. PROSERO protocol ID CRD42021260662.

RESULTS

Of 1386 articles screened, only three retrospective cohort studies met eligibility criteria. Two studies demonstrated no impact of age (< 70 years) on POC. Increased body mass index's (BMI) association with POC was present in one study (23.8 vs 21.7 kg/m2 , OR 1.67 (1.14-2.48), P = .01) and absent in another (< 30 vs 30-35 kg/m2 , P = .61). One study demonstrated decreased risk for postdonation subclinical hepatic dysfunction in donors with higher normal platelet count (PLT). None of the studies noted donor death. Given the scarce data on predonation physiologic testing, the expert panel recommended a battery of tests to guide clinical practice and future investigations.

CONCLUSION

Advancing age (60-69 years) is not a contraindication for liver donation. There is insufficient evidence for a specific predonation BMI cut-off. Abbreviated predonation physiologic testing is recommended in all candidates. Comprehensive testing is recommended in high-risk candidates while considering the pretest probability in various populations (Quality of evidence; Low to Very Low | Grade of Recommendation; Strong).

Dualistic role of platelets in living donor liver transplantation: Are they harmful?

Platelets are anucleate fragments mainly involved in hemostasis and thrombosis, and there is emerging evidence that platelets have other nonhemostatic potentials in inflammation, angiogenesis, regeneration and ischemia/reperfusion injury (I/R injury), which are involved in the physiological and pathological processes during living donor liver transplantation (LDLT). LDLT is sometimes associated with impaired regeneration and severe I/R injury, leading to postoperative complications and decreased patient survival. Recent studies have suggested that perioperative thrombocytopenia is associated with poor graft regeneration and postoperative morbidity in the short and long term after LDLT. Although it is not fully understood whether thrombocytopenia is the cause or result, increasing platelet counts are frequently suggested to improve posttransplant outcomes in clinical studies. Based on rodent experiments, previous studies have identified that platelets stimulate liver regeneration after partial hepatectomy. However, the role of platelets in LDLT is controversial, as platelets are supposed to aggravate I/R injury in the liver. Recently, a rat model of partial liver transplantation (LT) was used to demonstrate that thrombopoietin-induced thrombocytosis prior to surgery accelerated graft regeneration and improved the survival rate after transplantation. It was clarified that platelet-derived liver regeneration outweighed the associated risk of I/R injury after partial LT. Clinical strategies to increase perioperative platelet counts, such as thrombopoietin, thrombopoietin receptor agonist and platelet transfusion, may improve graft regeneration and survival after LDLT.

Safety and Threshold Analysis of Preoperative Platelets in Right Lobe Living Donors for Liver Transplantation

BACKGROUND

Low perioperative platelet count is a powerful independent risk factor for posthepatectomy liver failure. Usually, categorical effect of thrombocytopenia was taken into account; upper thresholds were not studied in depth, exclusively in living liver donors.

METHODS

Living liver donors who underwent right hepatectomy were included. Preoperative characteristics of donors were identified and examined to predict posthepatectomy liver failure. To eliminate selection bias, one-to-one propensity score matching was performed.

RESULTS

There were a total of 139 living donors and 40 (29%) donors developed posthepatectomy liver failure in the aftermath of the operation. Remnant liver volume ratio and preoperative platelet count were identified as adjustable independent risk factors (OR: 0.89 and 0.99, 95% CI: 0.79-0.99 and 0.98-0.99, respectively). After propensity score matching, odds ratio of preoperative platelet count was 0.99 (95% CI: 0.98-1.00).

CONCLUSIONS

Preoperative platelet count, in addition to remnant liver volume ratio, can be used as a surrogate marker to predict the risk of posthepatectomy liver failure in living liver right lobe donors. Probability curves figured out from logistic regression analysis, in this regard, provided an explicit perspective of platelets having a decisive role on liver donor safety. Thus, remaining in safer remnant liver volume ratio limits with respect to preoperative platelet count should be addressed in safe donor selection strategies.

The preoperative fibrosis score 4 predicts posthepatectomy liver failure in patients with hepatocellular carcinoma

INTRODUCTION AND OBJECTIVES

The fibrosis score 4 (FIB-4) has been identified as a biochemical surrogate for histological fibrogenesis and fibrosis in cirrhosis. This study investigates the impact of preoperative FIB-4 on postoperative liver failure of patients with hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Data from 205 patients who underwent curative resection for HCC were retrospectively analyzed. The receiver operating characteristic (ROC) curve analysis was performed to determine the cutoff value of the FIB-4. Univariate analysis and multivariate analysis were performed to identify risk factors for postoperative liver failure. The clinical outcomes were compared between patients with high FIB-4 and low FIB-4.

RESULTS

The optimal cutoff value of the FIB-4 was set at 5.92 for postoperative liver failure according to ROC curve. By univariate and multivariate analysis, the number of resected segments, FIB-4, and model for end-stage liver disease score were identified as independent risk factors for postoperative liver failure. Patients with preoperative FIB-4>5.92 had poorer liver function and higher occurrence of postoperative liver failure.

CONCLUSIONS

Preoperative FIB-4 was associated with postoperative liver failure. Patients with preoperative FIB-4>5.92 carry a high risk of postoperative liver failure.

Long-term impact and clinical significance of living donor liver transplantation with respect to donor liver restoration and spleen size: A prospective study

This study aimed to evaluate postoperative long-term liver restoration and splenic enlargement and their clinical significance in living donor liver transplantation. One hundred and sixteen donors who had donated livers more than 5 years previously accepted the invitation to participate in this study. The liver restoration rate and the splenic enlargement rate were calculated as the rate with respect to the original volume. The mean liver restoration rate was 0.99 ± 0.12 and older age was associated with a higher incidence for liver restoration rate <0.95 (P = .005), whereas type of donor operation was not. The donors with liver restoration rate <0.95 showed lower serum albumin levels than those with liver restoration rate ≥0.95. The mean splenic enlargement rate was 1.10 ± 0.16. Right lobe donors demonstrated higher splenic enlargement rate (1.14 ± 0.18) than left lobe/lateral segment donors (1.06 ± 0.13). In the donors with splenic enlargement rate ≥1.10, platelet count was not fully restored to the preoperative level. In conclusion, older age increases the risk for incomplete postoperative liver restoration, which may be associated with a decrease in albumin more than 5 years after donation. Right lobe donation poses a risk of splenic enlargement, which is associated with incomplete restoration of platelet count.