Thrombocytopenia, splenomegaly, and portal blood flow in patients who have undergone liver transplantation for cirrhosis

Spleen size change after hepatitis C treatment: a simple parameter to predict clinical outcomes

Portal hypertension contributes to splenomegaly in cirrhotic patients. Reduction in spleen size may represent improvement in portal hypertension. The goal was to determine whether reduction in spleen size following sustained virologic response (SVR) in patients with hepatitis C virus (HCV) cirrhosis is associated with lower risk of liver-related adverse outcomes. A retrospective cohort study was performed regarding HCV-infected patients treated with direct-acting antiviral agents at the Iowa City Veterans Administration Medical Center between 2014 and 2019. Patients with cirrhosis and splenomegaly on baseline ultrasound were included. Spleen size, platelet counts, decompensations, hepatocellular carcinoma (HCC) status, and mortality were recorded through July 31, 2021. Decrease in spleen size ≥1.5 cm was regarded as significant. Intergroup comparisons were performed on SPSS 28. Eighty patients with cirrhosis and splenomegaly before SVR were identified. Spleen sizes decreased significantly after SVR in 31 patients over a median of 1 year (Group A), whereas 49 patients did not meet this endpoint (Group B). Lack of spleen size reduction was associated with the presence of varices before SVR (odds ratio (OR): 5.3, p < 0.01). Group A had significantly greater increases in platelet count after SVR than did Group B. Patients in Group B had greater risk of HCC (OR: 9.7, CI: 1.2-79; p = 0.03) and death (OR: 3.6, CI: 1.1-12; p = 0.04). Reduced spleen size in patients with HCV cirrhosis after SVR is associated with greater increment in platelet count, decreased risk of HCC, and reduced mortality compared to patients whose spleen size does not decrease.

Early post-liver transplant thrombocytopenia in children: Clinical characteristics and significance

BACKGROUND

Post-liver transplant thrombocytopenia is common and associated with worse outcome in adults. In children, however, the prevalence, course, and significance of post-liver transplantation thrombocytopenia are not described. Therefore, we aimed to assess this phenomenon in children.

METHODS

A retrospective chart review of children who underwent liver transplantation at a single tertiary center between 2004 and 2021.

RESULTS

Overall, 130 pediatric liver transplantations were reviewed. During the first 28 POD, thrombocytopenia was evident in 116 (89%, 95% CI 83%-94%). The median nadir platelet count was 54 K/μl (IQR: 37-99). Nadir platelet count was reached in half the patients by the third POD (IQR: 1-6). In multivariate analysis, preoperative platelet count (p = .024), volume of intraoperative packed cell transfusion (p = .045), and hypersplenism (p = .007) were associated with lower postoperative platelet counts. Patients with platelet count lower than the 50th centile on the first POD suffered from a more complicated course leading to a longer PICU admission (p = .039).

CONCLUSIONS

Early post-liver transplant thrombocytopenia appears to be common in children and associated with preoperative thrombocytopenia, hypersplenism, and higher intraoperative blood transfusion volumes. A low first POD platelet count (<86 K/μl) was found to be independently associated with a more complicated postoperative course, suggesting the need for heightened surveillance.

Pretransplantation splenomegaly frequently persists after liver transplantation and can manifest as hypersplenism and graft fibrosis - a retrospective study

The risk factors and clinical impact of post-transplantation splenomegaly (SM) are poorly understood. We investigated the predictors and impacts of post-transplantation SM in 415 LT patients at Kyoto University Hospital from April 2006 to December 2015. First, the predictors and clinical consequences of SM three years post-transplantation were analyzed among spleen-preserved recipients. Second, the clinical data of surviving recipients three years post-transplantation were compared between splenectomized and spleen-preserved recipients. There was no difference in indication for liver transplantation between these two groups. Third, survival outcomes were compared between splenectomized and spleen-preserved recipients. SM was determined as a SV/body surface area (BSA) higher than 152 ml/m² . In the first analysis, preoperative SM occurred in 79.9% recipients and SM persisted three years post-transplantation in 72.6% recipients among them. Preoperative SV/BSA was the only independent predictor of three year post-transplantation SM, which was associated with lower platelet (PLT), white blood cell (WBC) counts and significant graft fibrosis (21.4% vs. 2.8%). In the second analysis, spleen-preservation was related to lower PLT, WBC counts and a higher proportion of significant graft fibrosis (26.7% vs. 7.1%) three years post-transplantation. In the third analysis, spleen-preserved recipients showed worse survival than splenectomized recipients. In conclusion, preoperative SM frequently persists more than three years post-transplantation and is associated with subclinical hypersplenism, graft fibrosis, graft loss, and even death.

MR angiography and 2-D phase-contrast imaging for evaluation of meso-rex bypass function

BACKGROUND

The meso-Rex bypass restores blood flow to the liver in patients with extrahepatic portal vein thrombosis. Stenosis occurs in some cases, causing the reappearance of portal hypertension. Complications such as thrombocytopenia present on a spectrum and there are currently no guidelines regarding a threshold for endovascular intervention. While Doppler ultrasound (US) is common for routine evaluation, magnetic resonance (MR) angiography with two-dimensional phase-contrast MRI (2-D PC-MRI) may improve the assessment of meso-Rex bypass function.

OBJECTIVES

To determine the feasibility and utility of MR angiography with 2-D PC-MRI in evaluating children with meso-Rex bypass and to correlate meso-Rex bypass blood flow to markers of portal hypertension.

MATERIALS AND METHODS

MR angiography and 2-D PC-MRI in meso-Rex bypass patients were retrospectively analyzed. Minimum bypass diameter was measured on MR angiography and used to calculate cross-sectional area. Meso-Rex bypass blood flow was measured using 2-D PC-MRI and divided by ascending aortic flow to quantify bypass flow relative to systemic circulation. Platelet and white blood cell counts were recorded. Correlation was performed between minimum bypass area, blood flow and clinical data.

RESULTS

Twenty-five children (median age: 9.5 years) with meso-Rex bypass underwent MR angiography and 2-D PC-MRI. The majority of patients were referred to imaging given clinical concern for complications. Eighteen of the 25 patients demonstrated >50% narrowing of the bypass cross-sectional area. The mean platelet count in 19 patients was 127 K/μL. There was a significant correlation between minimum cross-sectional bypass area and bypass flow (rho=0.469, P=0.018) and between bypass flow and platelet counts (r=0.525, P=0.021).

CONCLUSION

Two-dimensional PC-MRI can quantify meso-Rex bypass blood flow relative to total systemic flow. In a cohort of 25 children, bypass flow correlated to minimum bypass area and platelet count. Two-dimensional PC-MRI may be valuable alongside MR angiography to assess bypass integrity.

Low platelet count: Predictor of death and graft loss after liver transplantation

BACKGROUND

The impact of platelets on liver transplantation (LT) is well recognized, but not completely understood. Platelets exert dichotomous effects on the graft and on the patient. On the one hand, they are essential for primary hemostasis and tissue repair and regeneration. On the other hand, they support ischemia/reperfusion injury and inflammatory processes. Recent evidence has shown a new role for platelet count (PC) in predicting outcomes after LT.

AIM

To evaluate if low PC is a predictor of short- and long-term outcomes after LT.

METHODS

Four hundred and eighty consecutive LT patients were retrospectively assessed. PC from the preoperative to the seventh postoperative day (POD) were considered. C-statistic analysis defined the ideal cutoff point for PC. Cox regression was performed to check whether low PC was a predictor of death, retransplantation or primary changes in graft function within one year after LT.

RESULTS

The highest median PC was 86 × 10⁹/L [interquartile range (IQR) = 65–100 × 10⁹/L] on seventh POD, and the lowest was 51 × 10⁹/L (IQR = 38–71 × 10⁹/L) on third POD. The C-statistic defined a PC < 70 × 10⁹/L on fifth POD as the ideal cutoff point for predicting death and retransplantation. In the multivariate analysis, platelets < 70 × 10⁹/L on 5POD was an independent risk factor for death at 12 mo after LT [hazard ratio (HR) = 2.01; 95% confidence interval (CI) 1.06-3.79; P = 0.031]. In the Cox regression, patients with PC < 70 × 10⁹/L on 5POD had worse graft survival rates up to one year after LT (HR = 2.76; 95%CI 1.52-4.99; P = 0.001).

CONCLUSION

PC < 70 × 10⁹/L on 5POD is an independent predictor of death in the first year after LT. These results are in agreement with other studies that indicate that low PC after LT is associated with negative outcomes.

Therapeutic implication of platelets in liver regeneration -hopes and hues

Mounting evidence highlights platelet involvement in liver regeneration via interaction with liver cells, growth factors release, and signaling contributions. Existing research suggests a compelling biological rationale for utilizing platelet biology, with the goal of improving liver function and accelerating its regenerative potential. Despite its expanding application in several clinical areas, the contribution of the platelet and its therapeutic implementation in liver regeneration so far has not yet fulfilled the initial high expectations. Areas covered: This review scrutinizes the progress, current updates, and discusses how recent understanding - particularly in the clinical implications of platelet-based therapy - may enable strategies to introduce and harness the therapeutic potential of the platelet during liver regeneration. Expert commentary: Several clinical and translational studies have facilitated a platform for the development of platelet-based therapy to enhance liver regeneration. While some of these therapies are effective to augment liver regeneration, the others have had some detrimental outcomes. The existing evidence represents a challenge for future projects that are focused on directly incorporating platelet-based therapies to induce liver regeneration.

JOURNAL CLUB: Four-Dimensional Flow MRI-Based Splenic Flow Index for Predicting Cirrhosis-Associated Hypersplenism

OBJECTIVE

The objective of this study is to evaluate the ability of spleen volume, blood flow, and an index incorporating multiple measures to predict cirrhosis-associated hypersplenism.

MATERIALS AND METHODS

A total of 39 patients (14 women and 25 men; mean [± SD] age, 52 ± 10 years) with cirrhosis and sequelae of portal hypertension underwent 4D flow MRI and anatomic 3-T MRI performed before and after contrast administration. Unenhanced 4D flow MRI was used to assess abdominal hemodynamics, and splenic volumes were measured on T1-weighted gradient-recalled echo MRI. Relationships among demographic characteristics, blood component counts, splenic volume, arterial flow, venous flow, and the percentage of shunted portal flow were assessed in 29 consecutive patients (i.e., the derivation group), to develop a splenic flow index. This index was assessed along with splenic volume and blood flow alone in 10 additional consecutive patients (i.e., the validation group) via ROC curve analysis, to identify platelet counts of less than 50 × 10³ cells/μL, leukocyte counts of less than 3.0 × 10³ cells/μL, or both.

RESULTS

In the derivation cohort (platelet count, 129 ± 76 × 10³ cells/μL), splenic volume, arterial flow, venous flow, and the percentage of shunted portal flow were inversely correlated with platelet counts (ρ = -0.68, -0.68, -0.56, and -0.36, respectively; p < 0.05). Adding splenic volume to arterial flow and the product of venous flow and the percentage of shunted portal flow indexed to the body surface area yielded superior correlations with platelet counts, leukocyte counts, and the degree of severity of hypersplenism (ρ = -0.75, -0.48, and -0.75, respectively; p ≤ 0.001) and predicted severe hypersplenism (sensitivity, 100%; specificity, 100%) in the validation cohort (platelet count, 93 ± 71 × 10³ cells/μL).

CONCLUSION

A splenic flow index that incorporates both splenic volume and blood flow is a better indicator of hypersplenism than is splenic volume alone.

Transient Elastography for Spleen Stiffness Measurement in Patients With Cirrhosis: Role in Degree of Thrombocytopenia

OBJECTIVES

The purpose of our study was to evaluate the relationship between spleen stiffness measured by transient elastography and the degree of thrombocytopenia in patients with liver cirrhosis.

METHODS

A total of 67 patients with liver cirrhosis were prospectively enrolled in the study. All patients underwent single-day hematologic and biochemical tests, sonography, and transient elastography of the liver and spleen. Thrombocytopenia was categorized as mild (platelet count, 75,000-150,000/μL), moderate (50,000-75,000/μL), and severe (<50,000/μL).

RESULTS

The degree of thrombocytopenia was significantly correlated with spleen stiffness (P = .001) and spleen size (P = .002) but not with liver stiffness (P = .086). In patients without splenomegaly, spleen stiffness values were significantly higher in patients with thrombocytopenia than in those without thrombocytopenia (P = .035). In patients with splenomegaly, spleen stiffness values were significantly higher in patients with moderate to severe thrombocytopenia than in those with a normal platelet count or mild thrombocytopenia (P = .007). Compared to liver stiffness, spleen stiffness showed a better and statistically significant correlation with platelet count and spleen size in patients with cirrhosis.

CONCLUSIONS

The degree of thrombocytopenia was directly correlated with spleen stiffness, irrespective of the presence of splenomegaly. The clinical phenomenon of unexpected thrombocytopenia may be explained by a subtle or irreversible change in spleen stiffness.

Hypersplenism in liver disease and SLE revisited: current evidence supports an active rather than passive process

BACKGROUND

Active and passive theories have been advanced to explain splenomegaly and cytopenias in liver disease. Dameshek proposed active downregulation of hematopoiesis. Doan proposed passive trapping of blood components in a spleen enlarged by portal hypertension. Recent findings do not support a passive process.

DISCUSSION

Cytopenias and splenomegaly in both liver disease and systemic lupus erythematosus (SLE) poorly correlate with portal hypertension, and likely reflect an active process allocating stem cell resources in response to injury. Organ injury is repaired partly by bone-marrow-derived stem cells. Signaling would thus be needed to allocate resources between repair and routine marrow activities, hematologic and bone production. Granulocyte-colony stimulating factor (G-CSF) may play a central role: mobilizing stem cells, increasing spleen size and downregulating bone production. Serum G-CSF rises with liver injury, and is elevated in chronic liver disease and SLE. Signaling, not sequestration, likely accounts for splenomegaly and osteopenia in liver disease and SLE. The downregulation of a non-repair use of stem cells, bone production, suggests that repair efforts are prioritized. Other non-repair uses might be downregulated, namely hematologic production, as Dameshek proposed.

SUMMARY

Recognition that an active process may exist to allocate stem-cell resources would provide new approaches to diagnosis and treatment of cytopenias in liver disease, SLE and potentially other illnesses.

Immediate Postoperative Low Platelet Counts After Living Donor Liver Transplantation Predict Early Allograft Dysfunction

To investigate whether the platelets can improve liver function by mediating liver regeneration. Using a retrospective cohort with 234 consecutive adult-to-adult living donor liver transplantation recipients, we have discussed the relationship between immediate postoperative platelet count and outcome. Patients have been stratified into Low Platelet Group (106 patients) with platelet ≤68 × 10/L and High Platelet Group (128 patients) with platelet >68 × 10/L.Low Platelet Group has a higher rate of preoperative thrombocytopenia (90.6% vs. 32.8%, P<0.001), higher model for end-stage liver disease score (15 vs. 11, P<0.001), cirrhosis (86.8% vs. 76.6%, P=0.046), hepatorenal syndrome (18.2% vs. 4.0%, P=0.005) and fulminant hepatic failure (26.4% vs. 7.8%, P<0.001). The packed red blood cells transfusion (7.5 vs. 5, P = 0.023) and plasma transfusion (1275 mL vs. 800 mL, P=0.001) are more in patients with low platelet count. Low Platelet Group has a higher early allograft dysfunction (EAD) (22.6% vs. 7.0%, P=0.001) and severe complications (22.6% vs. 10.9%, P = 0.016). The 90-day mortality between the 2 groups is similar. The multivariate analysis has found that postoperative platelet ≤68 × 10/L is an independent risk factor for EAD.Platelet maybe influences the functional status of the liver by promoting graft regeneration after liver transplantation.

Spleen size in cirrhosis of different etiologies

OBJECTIVES

The purpose of this study was to evaluate the impact of cirrhosis etiology on spleen size as measured by sonography and computed tomography (CT).

METHODS

The spleen images of 139 patients with cirrhosis secondary to alcohol abuse, hepatitis C, or nonalcoholic steatohepatitis were reviewed retrospectively. The maximum diagonal spleen length on a single sonogram and maximum spleen diameter on axial, coronal, or sagittal CT, whichever was largest, was compared among the etiologic groups.

RESULTS

In 127 patients who underwent sonography, the mean spleen size ± SD on sonography in the alcohol group (13.1 ± 2.5 cm) was significantly smaller than in the hepatitis C (15.0 ± 3.4 cm) and nonalcoholic steatohepatitis (15.2 ± 3.0 cm) groups (95% confidence intervals of the mean difference, 0.6 to 3.3 and 0.8 to 3.4 cm, respectively). In 87 patients who underwent CT, the mean spleen size on CT in the alcohol group (14.0 ± 2.7 cm) was smaller than in the hepatitis C (15.9 ± 3.4 cm) and nonalcoholic steatohepatitis (15.5 ± 3.6 cm) groups, but the difference was not statistically significant. The spleen sizes on both sonography and CT in 79 patients were strongly correlated (r = 0.88; P < .0001).

CONCLUSIONS

Spleen size in patients with cirrhosis varies by the etiology of the disease. Therefore, to apply spleen size as a diagnostic or prognostic criterion in this context, it is important to recognize that cutoff values derived from spleen size in one etiologic group may not produce the same results when extrapolated to another etiologic group.

Use of analytic morphomics of liver, spleen, and body composition to identify patients at risk for cirrhosis

BACKGROUND & AIMS

A diagnosis of cirrhosis can be made on the basis of findings from imaging studies, but these are subjective. Analytic morphomics uses computational image processing algorithms to provide precise and detailed measurements of organs and body tissues. We investigated whether morphomic parameters can be used to identify patients with cirrhosis.

METHODS

In a retrospective study, we performed analytic morphomics on data collected from 357 patients evaluated at the University of Michigan from 2004 to 2012 who had a liver biopsy within 6 months of a computed tomography scan for any reason. We used logistic regression with elastic net regularization and cross-validation to develop predictive models for cirrhosis, within 80% randomly selected internal training set. The other 20% data were used as internal test set to ensure that model overfitting did not occur. In validation studies, we tested the performance of our models on an external cohort of patients from a different health system.

RESULTS

Our predictive models, which were based on analytic morphomics and demographics (morphomics model) or analytic morphomics, demographics, and laboratory studies (full model), identified patients with cirrhosis with area under the receiver operating characteristic curve (AUROC) values of 0.91 and 0.90, respectively, compared with 0.69, 0.77, and 0.76 for aspartate aminotransferase-to-platelet ratio, Lok Score, and FIB-4, respectively, by using the same data set. In the validation set, our morphomics model identified patients who developed cirrhosis with AUROC value of 0.97, and the full model identified them with AUROC value of 0.90.

CONCLUSIONS

We used analytic morphomics to demonstrate that cirrhosis can be objectively quantified by using medical imaging. In a retrospective analysis of multi-protocol scans, we found that it is possible to identify patients who have cirrhosis on the basis of analyses of preexisting scans, without significant additional risk or cost.

Platelet count reduction and outcomes in living liver donors

BACKGROUND

Platelet count reduction in living donors after graft harvesting is very common. The mechanisms and the subsequent adverse consequences are not clear. The present study was to explore the mechanisms and the consequences of platelet count reduction in living donors.

METHODS

We collected data from 231 living liver donor patients who donated at our transplant center between July 2002 and August 2009. Baseline and post-operative platelet counts were collected and analyzed. Multivariate logistic regression analysis was used to compare the risk factors for the persistent decrease in platelet counts. Complications and other post-operative recovery were compared between the donors.

RESULTS

Platelet count decreased differently at each of the follow-up intervals, and the average reduction from baseline evaluation to year 3 was 18.2%. A concomitant decrease in white blood cells was observed with platelet count reduction. All of the splenic volumes at the post-operative follow-up time points were significantly higher than those at baseline (P<0.01). Multivariate logistic regression analysis indicated that the graft-to-donor weight ratio was a risk factor for low post-operative platelet counts in living donors at the three follow-up time points: one week (P=0.047), one month (P=0.034), and three months (P=0.047). At the one week follow-up time, 77 donor platelet counts were higher (group 1) and 151 donor platelet counts were lower (group 2) than baseline levels. Two hemorrhage events (1.3%) were observed in group 2, while three hemorrhage events (3.9%) were observed in group 1 (P=0.211). The overall complication rate was comparable between the two groups (P=0.972).

CONCLUSION

An increase in harvesting graft may decrease platelet counts, but this reduction does not produce short- or long-term damage in living liver donors.

Low platelet counts after liver transplantation predict early posttransplant survival: the 60-5 criterion

Platelets play a critical role in liver injury and regeneration. Thrombocytopenia is associated with increases in postoperative complications after partial hepatectomy, but it is unknown whether platelet counts could also predict outcomes after transplantation, a procedure that is often performed in thrombocytopenic patients. Therefore, the aim of this study was to evaluate whether platelet counts could be indicators of short- and long-term outcomes after liver transplantation (LT). Two hundred fifty-seven consecutive LT recipients (January 2003-December 2011) from our prospective database were analyzed. Preoperative and daily postoperative platelet counts were recorded until postoperative day 7 (POD7). Univariate and multivariate analyses were performed to assess whether low perioperative platelet counts were a risk factor for postoperative complications and graft and patient survival. The median pretransplant platelet count was 88 × 10(9) /L [interquartile range (IQR) = 58-127 × 10(9) /L]. The lowest platelet counts occurred on POD3: the median was 56 × 10(9) /L (IQR = 41-86 × 10(9) /L). Patients with low platelet counts on POD5 had higher rates of severe (grade IIIb/IV) complications [39% versus 29%, odds ratio (OR) = 1.09 (95% CI = 1.1-3.3), P = 0.02] and 90-day mortality [16% versus 8%, OR = 2.25 (95% CI = 1.0-5.0), P = 0.05]. In the multivariate analysis, POD5 platelet counts < 60 × 10(9) /L were identified as an independent risk factor for grade IIIb/IV complications [OR = 1.96 (95% CI = 1.07-3.56), P = 0.03)], graft survival [hazard ratio (HR) = 2.0 (95% CI = 1.1-3.6), P = 0.03)], and patient survival [HR = 2.2 (95% CI = 1.1-4.6), P = 0.03)]. The predictive value of platelet counts for graft and patient survival was lost in patients who survived 90 days. In conclusion, after LT, platelet counts < 60 × 10(9) /L on POD5 (the 60-5 criterion) are an independent factor associated with severe complications and early graft and patient survival. These findings may help us to develop protective strategies or specific interventions for high-risk patients.

Portal vein complications after pediatric liver transplantation

Relatively few pediatric donors are available in relation to the number of children waiting for a liver transplant. This limited number of pediatric donor livers leads to the use of adult livers, usually requiring more complex portal vein (PV) anastomoses. These anastomoses are complicated by differences in PV caliber between donors and recipients, as well as by limitations of PV length, which may be inadequate to reach the recipient spleno-mesenteric junction. Three types of post-transplant complications result from these complexities: 1) anomalies of the portal flow; 2) stenosis of the PV anastomosis; and 3) PV thrombosis. Abnormal portal flow may rarely need a specific intervention, but persistent stenosis or appearance of signs of portal hypertension need to be corrected. Balloon dilatation and placement of a stent are usually successful to repair stenosis. Portal vein thromboses are in general diagnosed in the immediate post-operative period and frequently lead to re-transplantation; however, thrombolytic therapy should be attempted in children without major signs of liver necrosis. When intra-hepatic portal vein(s) are permeable, despite extrahepatic PV thrombosis, a Meso-Rex shunt may be the indicated therapy.