Transjugular Intrahepatic Portosystemic Shunt in Nonmalignant Noncirrhotic Portal Vein Thrombosis and Portosinusoidal Vascular Disorder.

Transjugular intrahepatic portosystemic shunt (TIPS) emerges as a key treatment for portal hypertension (PH) complications. While international guidelines provide clear indications for its use in cirrhosis, empirical knowledge is notably scarcer in non-cirrhotic PH, particularly in nonmalignant noncirrhotic portal vein thrombosis (NNPVT) and in patients with portosinusoidal vascular disorder (PSVD). Patients afflicted by these rare diseases exhibit distinct clinical profiles compared to their cirrhotic counterparts, often characterized by a younger age, predominantly preserved hepatic functionality even in cases of severe PH, and a higher propensity for extensive splanchnic thrombosis, which intricately complicates TIPS placement, posing unique challenges for its creation. The objective of this review is to synthesize existing literature on the effectiveness, safety, specific indications, and clinical outcomes of TIPS in adult patients with NNPVT or PSVD, focusing also on the technical challenges of TIPS insertion in the presence of portal cavernoma.

Profiling plasma alterations of extracellular vesicles in patients with acutely decompensated cirrhosis and bacterial infection.

BACKGROUND: Extracellular vesicles (EVs) modulate inflammation, coagulation and vascular homeostasis in decompensated cirrhosis. AIM: To characterize the profile of plasmatic EVs in patients with decompensated cirrhosis and bacterial infections and evaluate the association between EVs and the development of hemostatic complications. METHODS: We measured the levels of EVs using high-sensitivity flow cytometry and phospholipid-dependent clotting time (PPL) in a prospective cohort of hospitalized patients with acutely decompensated cirrhosis with versus without bacterial infections. A separate cohort of patients with bacterial infections without cirrhosis was also enrolled. We measured endothelium-, tissue factor (TF)-bearing, platelet- and leukocyte-derived EVs. In patients with infections, EVs were reassessed upon resolution of infection. Bleeding and thrombotic complications were recorded during 1-year follow-up. RESULTS: Eighty patients with decompensated cirrhosis were recruited (40 each with and without bacterial infections). Electron microscopy confirmed the presence of plasma EVs. Despite no difference in total EVs and PPL, patients with cirrhosis and infection had significantly higher TF+ EVs, P-Selectin+ EVs (activated platelet-derived), CD14+ EVs (monocyte/macrophages derived) and CD14+ TF+ EVs versus those with cirrhosis without infection. Upon infection resolution, levels of these EVs returned to those without infection. Patients with infections showed a significant association between reduced P-Selectin+ EVs and bleeding complications (HR 8.0 [95%CI 1.3-48.1]), whereas high levels of leukocyte-derived EVs (CD45+) and CD14+ EVs were significantly associated with thrombotic complications (HR 16.4 [95%CI 1.7-160] and 10.9 [95%CI 1.13-106], respectively). Results were confirmed in a validation cohort. CONCLUSION: Bacterial infections are associated with particular alterations of plasma EVs profile in decompensated cirrhosis. Bacterial infections trigger the release of EVs originating from various cell types, which may tip the precarious hemostatic balance of patients with acutely decompensated cirrhosis towards hyper- or hypocoagulability.

Porto-sinusoidal vascular disorder in chronic HBV: A significant coexistence not to be overlooked.

Background & Aims: Porto-sinusoidal vascular disorder (PSVD) encompasses a group of liver diseases with vascular abnormalities that can cause portal hypertension in the absence of cirrhosis. The new diagnostic criteria allow for coexistence with other liver diseases, however its relationship with chronic hepatitis B (CHB) remains unclear. This study aimed to assess HBV prevalence in a PSVD cohort and evaluate its clinical impact. Methods: This retrospective study was conducted on patients with PSVD at Hospital Clínic Barcelona. HBV serology was evaluated, and patients were categorized into HBV chronic infection, past infection, or no HBV exposure. Clinical characteristics and outcomes were compared. Results: We included 155 patients with PSVD. Prevalence of CHB and past HBV infection in patients with PSVD was higher than in the general population (5.8% vs. 0.5%, p <0.0001 and 20% vs. 9.1%, p <0.0001, respectively). Patients with CHB had a significant delay in PSVD diagnosis compared to those without CHB (11 [5-25] vs. 1 [0-3] years, p = 0.002) and had a more advanced disease (MELD score 12 [9-17] vs. 9 [7-11], p = 0.012) at the time of PSVD diagnosis. The clinical evolution of PSVD in patients with CHB was marked by a significantly higher transplantation rate at the last follow-up (33% vs. 4.1%, p = 0.001). Conclusions: Recognizing the coexistence of PSVD and CHB is important for timely diagnosis and optimal management, highlighting the potential benefits of specialized care for potentially improved outcomes. Impact and implications: The new diagnostic criteria for porto-sinusoidal vascular disorder (PSVD) allow for coexistence with other liver diseases. The results of the present study highlight, for the first time, a non-negligible prevalence of chronic hepatitis B in the PSVD population that was previously unknown. Coexistence may challenge and delay the PSVD diagnosis and is associated with a more unfavorable clinical course. Our findings will increase awareness of this coexistence and improve PSVD diagnosis and management. Furthermore, the data will encourage new studies to determine the prevalence and clinical behavior of other chronic liver diseases that coexist with PSVD.

Role of sex in liver tumor occurrence and clinical outcomes: A comprehensive review.

Clinical research on sex-based differences in the manifestations, pathophysiology, and prevalence of several diseases, including those affecting the liver, has expanded considerably in recent years. Increasing evidence suggests that liver diseases develop, progress, and respond to treatment differently depending on the sex. These observations support the concept that the liver is a sexually dimorphic organ in which estrogen and androgen receptors are present, which results in disparities between men and women in liver gene expression patterns, immune responses, and the progression of liver damage, including the propensity to develop liver malignancies. Sex hormones play protective or deleterious roles depending on the patient's sex, the severity of the underlying disease, and the nature of precipitating factors. Moreover, obesity, alcohol consumption, and active smoking, as well as social determinants of liver diseases leading to sex-related inequalities, may interact strongly with hormone-related mechanisms of liver damage. Drug-induced liver injury, viral hepatitis, and metabolic liver diseases are influenced by the status of sex hormones. Available data on the roles of sex hormones and gender differences in liver tumor occurrence and clinical outcomes are conflicting. Here, we critically review the main gender-based differences in the molecular mechanisms associated with liver carcinogenesis and the prevalence, prognosis, and treatment of primary and metastatic liver tumors.

Role of nonneoplastic PVT in the natural history of patients with cirrhosis and first diagnosis of HCC.

BACKGROUND AND AIMS: HCC can increase the risk of nonneoplastic PVT in cirrhosis. However, the natural history of PVT and its prognostic role in HCC patients are unknown. APPROACH AND RESULTS: Consecutive HCC patients with cirrhosis undergoing laparoscopic ablation were retrospectively evaluated and followed up to 36 months. HCC and PVT characteristics and evolution were reviewed. PVT was categorized according to lumen occupancy (≤50%, >50% <100%, and = 100%) and extension to other veins. The evolution of thrombosis was considered at 1 year from diagnosis. Variables associated with the presence of PVT and evolution patterns were analyzed, as well as their impact on survival. In all, 750 patients were included, 88 of whom had PVT. On multivariate analysis, the occurrence of PVT at HCC diagnosis was associated with pretreatment total tumor volume ( p < 0.001) and clinically significant portal hypertension ( p = 0.005). During the follow-up, 46 de novo PVT occurred, 27/46 (58.7%) in the presence of a viable tumor. Among 115 PVT diagnosed in the presence of HCC, 83 had available radiological follow-up, and 22 were anticoagulated. The "complete/progressive" evolution pattern was associated with nonresponse to HCC treatment in non-anticoagulated patients. The presence of PVT was independently associated with lower overall survival, particularly when progressive or occlusive ( p < 0.001). A higher competing risk of death emerged for "complete and progressive" PVT, both for HCC-related ( p < 0.001) and non-HCC-related ( p = 0.002) death. CONCLUSIONS: HCC represents an independent risk factor for the occurrence and progression of PVT in cirrhosis. Since progressive and occlusive PVT seems to be an independent factor associated with mortality, screening and prompt treatment of this complication should be considered.

The genetics of portal hypertension: Recent developments and the road ahead.

Portal hypertension (PH), defined as a pathological increase in the portal vein pressure, has different aetiologies and causes. Intrahepatic PH is mostly secondary to the presence of underlying liver disease leading to cirrhosis, characterized by parenchymal changes with deregulated accumulation of extracellular matrix and vascular abnormalities; liver sinusoidal endothelial cells and hepatic stellate cells are key players in PH progression, able to influence each other. However, PH may also develop independently of parenchymal damage, as occur in portosinusoidal vascular disorder (PSVD), a group of clinical and histological entities characterized by portal vasculature dysfunctions. In this particular group of disorders, the pathophysiology of PH is still poorly understood. In the last years, several genetic studies, based on genome-wide association studies or whole-exome sequencing analysis, have highlighted the importance of genetic heritability in PH pathogenesis, both in cirrhotic and non-cirrhotic cases. The common PNPLA3 p.I148M variant, one of the main determinants of the susceptibility to steatotic liver disease, has also been associated with decompensation in patients with PH. Genetic variations at loci influencing coagulation, mainly the ABO locus, may directly contribute to the pathogenesis of PH. Rare genetic variants have been associated with familiar cases of progressive PSVD. In this review, we summarize the recent knowledges on genetic variants predisposing to PH development, contributing to better understand the role of genetic factors in PH pathogenesis.

Changings and Challenges in Liver Transplantation for Nonalcoholic Fatty Liver Disease/Steatohepatitis.

Liver transplantation for nonalcoholic fatty liver disease/steatohepatitis (NAFLD/NASH) is increasing rapidly worldwide. Compared with alcohol and viral-related liver disease, NAFLD/NASH is more frequently associated with a systemic metabolic syndrome, which significantly affects other organs, requiring multidisciplinary management, in all phases of liver transplant.

Vascular liver diseases: A sex-oriented analysis of the literature.

Vascular liver diseases are an heterogenous group of diseases that collectively represent an important health issue in the field of liver diseases. This narrative review was elaborated by the Special Interest Group (SIG) "Gender in Hepatology" of the Italian Association for the Study of the Liver (AISF). We aimed to review the current knowledge regarding the potential role of biological sex in patients with vascular liver diseases such as splanchnic vein thrombosis, hepatic vein thrombosis, porto-sinusoidal vascular disorder, and hereditary hemorrhagic telangiectasia. As vascular liver diseases commonly affect young individuals, including women in childbearing age, we also included a specific section on the management of pregnancy in these challenging patients.

Global hemostatic profiling in patients with decompensated cirrhosis and bacterial infections.

Background & Aims: Bacterial infections in cirrhosis are associated with increased bleeding risk. To assess the factors responsible for bleeding tendency in patients with bacterial infections, we conducted a prospective study comparing all 3 aspects of hemostasis (platelets, coagulation, and fibrinolysis) in hospitalized patients with decompensated cirrhosis with vs. without bacterial infections. Methods: Primary hemostasis assessment included whole blood platelet aggregation and von Willebrand factor (VWF). Coagulation assessment included procoagulant factors (fibrinogen, factor II, V, VII, VIII, IX, X, XI, XII, XIII), natural anticoagulants (protein C, protein S, antithrombin) and thrombomodulin-modified thrombin generation test. Fibrinolysis assessment included fibrinolytic factors (plasminogen, t-PA, PAI-1, α2-AP, TAFIa/ai) and plasmin-antiplasmin complex (PAP). Results: Eighty patients with decompensated cirrhosis were included (40 with and 40 without bacterial infections). Severity of cirrhosis and platelet count were comparable between groups. At baseline, patients with cirrhosis and bacterial infections had significantly lower whole blood platelet aggregation, without significant differences in VWF. Regarding coagulation, bacterial infections were associated with reduced procoagulant factors VII and XII, and a significant reduction of all natural anticoagulants. However, thrombomodulin-modified thrombin generation was comparable between the study groups. Finally, although mixed potentially hypo-fibrinolytic (lower plasminogen) and hyper-fibrinolytic (higher t-PA) changes were present in bacterial infections, a comparable level of PAP was detected in both groups. Upon resolution of infection (n = 29/40), platelet aggregation further deteriorated whereas coagulation and fibrinolysis factors returned to levels observed in patients without bacterial infections. Conclusion: In hospitalized patients with decompensated cirrhosis, bacterial infections are associated with reduced whole blood platelet aggregation and a significant decrease of all natural anticoagulants, which may unbalance hemostasis and potentially increase the risk of both bleeding and thrombosis. Lay summary: Bacterial infections are a common issue in hospitalized patients with decompensated cirrhosis (i.e. patients hospitalized due to severe complications of advanced chronic liver disease). Patients with decompensated cirrhosis who acquire infections may be at increased risk of bleeding complications following invasive procedures (that is a procedure in which the body is penetrated or entered, for instance by a needle or a tube). As bleeding complications in decompensated cirrhosis are associated with a high risk of further decompensation and death, there is an urgent need to understand the factors responsible for such increased bleeding tendency. Herein, we investigated the alterations of hemostasis (that is the physiological process responsible for clot formation and stability) in patients with decompensated cirrhosis and bacterial infections. We found that development of bacterial infections in these patients is associated with alterations of hemostasis (particularly of platelets and clotting cascade) that may increase the risk of both bleeding and thrombotic complications.

Immune Activation, Exhaustion and Senescence Profiles as Possible Predictors of Cancer in Liver Transplanted Patients.

Liver transplanted (LT) patients for hepatocellular carcinoma (LT-HCC) or for other causes (LT-no-HCC) may develop post-transplantation malignancies. Although immune activation and senescence are frequently implicated in cancer development, no data is available on their possible role as biomarkers predictive of tumor onset in this setting. A total of 116 patients were investigated: the 45 LT-HCC patients were older than the 71 LT-non-HCC (p=0.011), but comparable for sex, HCV, HBV infection and immunosuppressive treatment. At baseline, the numbers of activated and senescent-like circulating cells were significantly higher in LT-HCC patients than in LT-no-HCC ones. After a median follow-up of 26.8 months, 6 post-transplant malignancies (PTM) occurred: 4 in LT-HCC (8.9%) and 2 in LT-no-HCC (2.8%) patients. Overall, subjects with high percentages of activated and exhausted T and B cells at baseline were at higher risk of PTM. Notably, within the LT-HCC group, a higher percentage of senescence-like T cells was also associated with cancer development. Moreover, patients with PTM had higher telomere erosion and higher levels of circulating PAMPs (16S rDNA) and DAMPs (mtDNA) when compared with matched patients without PTM. Overall, these findings suggest that immune activation and exhaustion may be useful to predict the risk of PTM occurrence, regardless of the cause of transplantation. In LT-HCC, T-cell senescence represents an additional risk factor for tumor onset.

An Essential Guide for Managing Post-Liver Transplant Patients: What Primary Care Physicians Should Know.

With long-term survival after liver transplantation becoming the rule, care for medical problems arising over time in liver-transplanted patients gained increasing importance. The most common causes of death occurring more than 1 year after liver transplantation are unrelated to liver diseases and facilitated by immunosuppressive treatments; examples are malignancies, renal failure, and cardiovascular, metabolic, and infectious diseases. Recipients receive life-long follow-up care at transplant centers, however, the increasing number of liver-transplanted patients is saturating the health care supply that transplant centers have to offer. Primary care physicians are increasingly exposed to liver-transplanted patients, even in the early periods after transplant, and an understanding of the most common risks and complications faced by these patients would enhance their care. This article reviews the long-term care of liver transplant recipients, emphasizing the key internal medicine-related issues that should be known by primary care physicians. A specific section is devoted to implementing strategies to involve these physicians in the long-term follow-up of liver-transplanted patients in close collaboration with transplant hepatologists.

Hepatocellular carcinoma recurrence after direct-acting antiviral therapy: an individual patient data meta-analysis.

OBJECTIVE: The benefit of direct-acting antivirals (DAAs) against HCV following successful treatment of hepatocellular carcinoma (HCC) remains controversial. This meta-analysis of individual patient data assessed HCC recurrence risk following DAA administration. DESIGN: We pooled the data of 977 consecutive patients from 21 studies of HCV-related cirrhosis and HCC, who achieved complete radiological response after surgical/locoregional treatments and received DAAs (DAA group). Recurrence or death risk was expressed as HCC recurrence or death per 100 person-years (100PY). Propensity score-matched patients from the ITA.LI.CA. cohort (n=328) served as DAA-unexposed controls (no-DAA group). Risk factors for HCC recurrence were identified using random-effects Poisson. RESULTS: Recurrence rate and death risk per 100PY in DAA-treated patients were 20 (95% CI 13.9 to 29.8, I2=74.6%) and 5.7 (2.5 to 15.3, I2=54.3), respectively. Predictive factors for recurrence were alpha-fetoprotein logarithm (relative risk (RR)=1.11, 95% CI 1.03 to 1.19; p=0.01, per 1 log of ng/mL), HCC recurrence history pre-DAA initiation (RR=1.11, 95% CI 1.07 to 1.16; p<0.001), performance status (2 vs 0, RR=4.35, 95% CI 1.54 to 11.11; 2 vs 1, RR=3.7, 95% CI 1.3 to 11.11; p=0.01) and tumour burden pre-HCC treatment (multifocal vs solitary nodule, RR=1.75, 95% CI 1.25 to 2.43; p<0.001). No significant difference was observed in RR between the DAA-exposed and DAA-unexposed groups in propensity score-matched patients (RR=0.64, 95% CI 0.37 to 1.1; p=0.1). CONCLUSION: Effects of DAA exposure on HCC recurrence risk remain inconclusive. Active clinical and radiological follow-up of patients with HCC after HCV eradication with DAA is justified.

Recent Advances in the Management of Acute Variceal Hemorrhage.

Gastrointestinal bleeding is one of the most relevant causes of death in patients with cirrhosis and clinically significant portal hypertension, with gastroesophageal varices being the most frequent source of hemorrhage. Despite survival has improved thanks to the standardization on medical treatment aiming to decrease portal hypertension and prevent infections, mortality remains significant. In this review, our goal is to discuss the most recent advances in the management of esophageal variceal hemorrhage in cirrhosis with specific attention to the treatment algorithms involving the use of indirect measurement of portal pressure (HVPG) and transjugular intrahepatic portosystemic shunt (TIPS), which aim to further reduce mortality in high-risk patients after acute variceal hemorrhage and in the setting of secondary prophylaxis.

New Indications for Liver Transplantation.

Liver transplantation (LT) is an important therapeutic option for the treatment of several liver diseases. Modern LT is characterized by remarkable improvements in post-transplant patient survival, graft survival, and quality of life. Thanks to these great improvements, indications for LT are expanding. Nowadays, clinical conditions historically considered exclusion criteria for LT, have been considered new indications for LT, showing survival advantages for patients. In this review, we provide an updated overview of the principal newer indications for LT, with particular attention to alcoholic hepatitis, acute-on-chronic liver failure (ACLF), cholangiocarcinoma and colorectal cancer metastases.

More Pronounced Hypercoagulable State and Hypofibrinolysis in Patients With Cirrhosis With Versus Without HCC.

In patients with cirrhosis, particularly those with hepatocellular carcinoma (HCC), hypercoagulability may be associated with purported increased risks of portal vein thrombosis and cirrhosis progression. In this study, we extensively investigated hemostatic alterations potentially responsible for the thrombotic tendency in HCC, and evaluated whether such alterations were predictive of hepatic decompensation. Patients with cirrhosis at all stages were prospectively recruited and underwent an extensive hemostatic assessment, including all procoagulant factors and inhibitors, thrombin generation with and without thrombomodulin (TG), profibrinolytic and antifibrinolytic factors, and plasmin-antiplasmin complex. In study part 1 (case control), we compared alterations of coagulation and fibrinolysis in patients with cirrhosis with versus without HCC. In study part 2 (prospective), the subgroup of patients with decompensated cirrhosis was followed for development of further decompensation, and predictors of outcome were assessed by multivariate analysis. One-hundred patients were recruited (50 each with and without HCC). Severity of cirrhosis was comparable between groups. Median HCC volume was 9 cm3 (range: 5-16). Compared with controls, patients with HCC demonstrated a significantly more prothrombotic hemostatic profile due to increased TG and reduced activation of fibrinolysis, independent of cirrhosis stage. During a median follow-up of 175 days, 20 patients with decompensated cirrhosis developed further episodes of decompensation that were predicted by low FVII and high plasminogen activator inhibitor-1 levels, independent of Model for End-Stage Liver Disease score. Conclusion: Patients with cirrhosis with HCC have profound hyper-coagulable changes that can account for their increased thrombotic tendency. In contrast, hypercoagulability in patients with decompensated cirrhosis is more likely a consequence of chronic liver disease rather than a driver for cirrhosis progression.

Comparison of Fondaparinux and Low-Molecular-Weight Heparin in the Treatment of Portal Vein Thrombosis in Cirrhosis.

BACKGROUND: Portal vein thrombosis is the most common thrombotic complication in cirrhosis. About 60% of anticoagulated patients can achieve recanalization. Despite fondaparinux (FPX) theoretical advantages, data are lacking about safety and efficacy for treatment of portal vein thrombosis in cirrhosis. METHODS: Cirrhotic patients with portal vein thrombosis treated with FPX or low-molecular-weight heparin (LMWH) were retrospectively included. The extension of thrombosis at baseline and its evolution during anticoagulant treatment were evaluated. Patients were treated with LMWH or FPX at therapeutic dosage and reduction was considered in selected cases. RESULTS: There were 124 patients included. Main portal vein branch, splenic, and superior mesenteric veins were involved in 84%, 13%, and 36% of cases, respectively. Forty-one patients (33%) were treated with FPX and 83 (67%) with LMWH. The probability of resolution of thrombosis at 36 months was significantly higher in patients treated with FPX than in those treated with LMWH (77% vs 51%; P = .001), particularly when prescribed at reduced dose. With multivariate analysis, the treatment with FPX (hazard ratio 2.38; P = .002) and use of a full dose (hazard ratio 1.78; P = .035) were independent predictors of portal vein full recanalization. Bleeding rate was higher in patients treated with FPX than in those treated with LMWH (27% vs 13%; P = .06). CONCLUSIONS: FPX appears to be more effective than LMWH in the treatment of portal vein thrombosis when used at reduced dose, also in complete thrombosis. FPX should be considered among possible treatments for portal vein thrombosis in cirrhosis.

Clinical impact of sexual dimorphism in non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH).

NAFLD/NASH is a sex-dimorphic disease, with a general higher prevalence in men. Women are at reduced risk of NAFLD compared to men in fertile age, whereas after menopause women have a comparable prevalence of NAFLD as men. Indeed, sexual category, sex hormones and gender habits interact with numerous NAFLD factors including cytokines, stress and environmental factors and alter the risk profiles and phenotypes of NAFLD. In the present review, we summarized the last findings about the influence of sex on epidemiology, pathogenesis, progression in cirrhosis, indication for liver transplantation and alternative therapies, including lifestyle modification and pharmacological strategies. We are confident that an appropriate consideration of sex, age, hormonal status and sociocultural gender differences will lead to a better understanding of sex differences in NAFLD risk, therapeutic targets and treatment responses and will aid in achieving sex-specific personalized therapies.

Influence of Hepatocellular Carcinoma on Platelet Aggregation in Cirrhosis.

Hyper-functional platelets are being proposed as a potential therapeutic target in multiple cancers. Whether this can be considered in patients with cirrhosis and hepatocellular carcinoma (HCC) is unknown as their platelet function has not yet been investigated. We evaluated platelet function in cirrhosis patients with HCC. Patients with cirrhosis with and without HCC were prospectively recruited. Platelet aggregation, a marker of platelet function, was assessed by impedance aggregometry with adenosine diphosphate (ADP), arachidonic acid (ASPI), and thrombin (TRAP) stimulation. Plasmatic levels of Von Willebrand factor antigen (VWF) were also determined. One-hundred patients were recruited (50 cirrhotics with and 50 without HCC). Cirrhosis severity by Child class and platelet count were comparable between cirrhotics with and without HCC. Cirrhotics with HCC had higher ADP- (45 vs. 28; p < 0.001), ASPI- (47 vs. 28; p < 0.001), and TRAP- (85 vs. 75; p = 0.01) induced platelet aggregation than cirrhotics without HCC, all indicative of platelet hyper-function. The relatively increased platelet aggregation in patients with HCC was confirmed after adjusting the analysis for platelet count/severity of thrombocytopenia. Levels of VWF were higher in patients with vs. without HCC (348 vs. 267; p = 0.006), particularly in compensated cirrhosis. In patients with cirrhosis, HCC is associated with increased platelet aggregation and higher VWF. The clinical implications of these findings deserve further investigation.