Prevalence and outcome of portal thrombosis in a cohort of cirrhotic patients undergoing liver transplantation

1130-0108/2016/108/11/716-720 Revista Española de Enfermedades Digestivas Copyright 2016. SEPD y ARÁN EDICIONES, S.L. Rev Esp Enferm Dig 2016, Vol. 108, N.º 11, pp. 716-720 ORIGINAL PAPERS Prevalence and outcome of portal thrombosis in a cohort of cirrhotic patients undergoing liver transplantation Marta Hernández-Conde 1, Elba Llop 1, Juan de-la-revilla 1, Fernando Pons 1, Natalia Fernández-Puga 1, José Luis Martínez-Porras 1, María Trapero 1, Valentín Cuervas-Mons 2, Víctor Sánchez-Turrión 3 and José Luis Calleja 1 Departments of 1 Gastroenterology and Hepatology, 2 Internal Medicine, and 3 Surgery. Hospital Universitario Puerta de Hierro Majadahonda. Majadahonda, Madrid. Spain ABSTRACT Introduction: The prevalence of portal vein thrombosis (PVT) in patients that have undergone liver transplantation (LT) is 9.7% (SD 4.5). The aim of our study was to determine the prevalence, assess the factors that are associated with PVT and clarify their association with prognosis in patients with liver cirrhosis (LC) and LT. Aims and methods: From 2005 to 2014, laboratory, radiological and surgical data were collected from patients with LC in our center who had undergone LT for the first time. Results: One hundred and ninety-one patients were included. The mean age was 55 (SD 9), 75.4% of patients were male and 48.7% had HCV. The Child-Pugh scores were A/B/C 41.9%/35.9%/25.5% and the MELD score was 15 (SD 6). Previous decompensations were: ascites (61.4%), hepatic encephalopathy (34.4%), variceal bleeding (25.4%), hepatocellular carcinoma (48.9%) and spontaneous bacterial peritonitis (SPB) (14.3%). The mean post-transplant follow-up was 42 months (0-113). PVT was diagnosed at LT in 18 patients (9.4%). Six patients were previously diagnosed using imaging tests (33.3%): 2 patients (11.1%) by DU and 4 patients (22.2%) by CT scan. All patients with PVT had DU in a mean time of 6 months before LT (0-44) and 90 patients (47.1%) had a CT scan in a median time of 6 months before LT (0-45). PVT was significantly related to the presence of SBP (33.3% vs 12.6%; p = 0.02) and lower levels of albumin (3.1g/dl vs 3.4g/ dl; p = 0.05). MELD was higher in patients with PVT (16.6 vs 14.9; p = 0.3). There were no significant differences with regard to the need for transfusion of blood components. Moreover, the surgery time was similar in both groups. PVT correlated with a higher mortality in the first 30 days (8.8% vs 16.7%; p = 0.2). Conclusion: Prior history of SBP and lower levels of albumin were identified as factors associated with PVT. The pre-transplant diagnosis rate is very low and the presence of PVT may have implications for short-term mortality. Key words: Portal vein thrombosis. Liver transplant. Cirrhosis. INTRODUCTION Thrombotic episodes are more frequent in patients with liver cirrhosis (1). Portal vein thrombosis (PVT) has a prevalence of 10%-25% in patients without hepatocellular carcinoma (HCC) and 33% in patients with HCC (2,3). The pathophysiology of PVT in liver cirrhosis is complex. It is believed that two of the factors are a decreased portal flow and a hypercoagulable state that exists in these patients (4). In a prospective study, decreased flow rate in the portal vein was the only variable predictive of the development of PVT in a cohort of 73 patients with liver cirrhosis (LC) (5). Other studies have shown an increase in factor VIII in patients with LC, which has been shown to be a risk factor associated with PVT (6,7). In addition, molecular studies have shown that some thrombophilic genotypes, including the factor V Leiden mutation, may be more frequent in cirrhotic patients with PVT compared with cirrhotic patients without PVT, which is further demonstrated by the fact that the TT677 polymorphism of methylenetetrahydrofolate reductase and the G20210A polymorphism of the prothrombin gene are more frequent in PVT patients (8,9). PVT usually presents without symptoms, although it is not uncommon to present as ascitis, upper gastrointestinal bleeding from esophageal varices or portal hypertension gastropathy. Less frequently, it can cause acute abdominal pain which is associated with an increased frequency of intestinal infarction (9). The initial diagnosis is usually made by abdominal Doppler ultrasound (DU), with sufficient sensitivity for grades III-IV with the classification of Yerdel (Table I) of 92%- 100% and with much lower sensitivity for partial PVT (14.3%-50%). Performing an angio-ct scan or angio-mri confirms the diagnosis and allows for the extension of the thrombosis to be determined. Many authors have classified PVT by its extent and severity with the most commonly used classification being the one proposed by Yerdel (1). Despite having a pre-liver transplantation (LT) radiological study, 12% to 63.7% of PVT are diagnosed during surgery, although the exact proportion is not known (10). Predictive factors of PVT in a small series of patients have been described. The appearance of PVT seems to appear more frequently in patients with advanced LC Received: 22-01-2016 Accepted: 05-09-2016 Correspondence: Marta Hernández-Conde. Department of Gastroenterology and Hepatology. Hospital Universitario Puerta de Hierro Majadahonda. C/ Manuel de Falla, 1. 28222 Majadahonda, Madrid. Spain e-mail: Marta.hernandez.conde@gmail.com Hernández-Conde M, Llop E, De-la-Revilla J, Pons F, Fernández-Puga N, Martínez-Porras JL, Trapero M, Cuervas-Mons V, Sánchez-Turrión V, Calleja JL. Prevalence and outcome of portal thrombosis in a cohort of cirrhotic patients undergoing liver transplantation.. DOI: 10.17235/reed.2016.4211/2016

2016, Vol. 108, N.º 11 PREVALENCE AND OUTCOME OF PORTAL THROMBOSIS IN A COHORT OF CIRRHOTIC PATIENTS 717 UNDERGOING LIVER TRANSPLANTATION Grade I Grade II Grade III Grade IV Table I. Yerdel classification Minimal or partial thrombosis of the PV (< 50% luminal space) with or without minimal extension of the superior mesenteric vein (SMV) > 50% occlusion of the PV, including complete thrombosis, with or without minimal extension in SMV Complete thrombosis of the proximal VP and SMV Complete thrombosis of the VP and SMV (proximal and distal) (Child Pugh C) (1,11). Nonami et al. (3) observed that patients with chronic hepatic encephalopathy, refractory ascites, gastrointestinal bleeding or splenomegaly had a higher PVT incidence. Yerdel et al. (1) established that PVT is significantly more common in patients with prior treatment for bleeding portal hypertension (sclerotherapy, transjugular intrahepatic portosystemic shunt (TIPs), shunt surgery and splenomegaly), and that this effect increased with the severity of liver disease (Child-Pugh C). Moreover, thrombocytopenia appears to be an independent risk factor for PVT in liver cirrhosis (5). The inverse correlation between the number of platelets and PVT may be due to the fact that the decrease in portal flow secondary to portal hypertension exceeds the possible protective effect of thrombocytopenia (12). The impact that PVT has in the natural history of cirrhosis and LT remains uncertain (12). In a systematic review of the literature by Rodríguez-Castro KI et al. (13), there is evidence that the prevalence of PVT in patients undergoing LT is 9.7% ± 4.5% (with partial PVT being more frequent than complete PVT (12). It also appears that the need for transfusion of blood components is higher in patients with PVT (1,14). Numerous studies have shown that there is no statistically significant difference in post-lt survival between cirrhotic patients with or without PVT (15,16). However, the largest series available to date suggests that, regardless of the MELD score, pre-transplant PVT may be associated with a 50% mortality risk in the first year post-lt (11). Therefore, the aim of our study was to determine the prevalence of PVT in the explanted liver of patients undergoing LT and to evaluate the pre-lt factors associated with the presence of PVT and prior radiological diagnosis of PVT. Finally, we evaluated the impact of the presence of PVT on post-lt evolution. Patients who underwent LT due to fulminant liver failure or who did not suffer from cirrhosis were excluded from the study. At all times, the study was conducted in accordance with the standards of good clinical practices and in compliance with pertinent ethical guidelines (the 6 th revision of the Declaration of Helsinki of the World Medical Association at the 59 th General Assembly, Seoul, 2008). Statistical analysis was performed using SPSS 21.0 software (SPSS Inc., Chicago, IL, USA). Quantitative data are described as the mean and standard deviation or median and range where appropriate. Qualitative data are described in percentages. The Chi-square test was used to compare proportions and t-student tests were used to compare means. Differences were considered to be statistically significant when the p value was less than 0.05. RESULTS From January 2005 to June 2014, 261 patients received an LT. Of them, 191 patients met the inclusion criteria and were considered for the study. Of those patients not meeting the criteria (n = 70), 32 were excluded due to having a previous LT, 30 of them were not cirrhotic and 8 of them did not have sufficient data (Fig. 1). Patient baseline demographic and transplant characteristics are shown in tables II and III. The median patient follow-up in the study, from the LT to death or loss of follow-up, was 42 months (range 0-113). PVT was present during LT in 18 patients (9.4%), of which only 6 patients were diagnosed by imaging tests prior to LT. The other 12 patients were diagnosed de 261 screened patients 32 had had a previous LT PATIENTS AND METHODS This is a retrospective study with a prospective collection of data. Data were collected in consecutive patients with liver cirrhosis of any etiology undergoing their first LT at the Hospital Universitario Puerta de Hierro, Majadahonda (Madrid, Spain). Pre-LT clinical, laboratory and radiological data were collected as well as protocol data from surgery and post-lt clinical evolution. PVTs were classified based on the Yerdel classification (1). Inclusion criteria were the following: patients over 18 years of age, undergoing a first liver transplant and diagnosed with cirrhosis. 191 patients met all inclusion criteria Fig 1. Patient disposition. 70 patients were excluded 30 were not cirrhotic 8 did not have sufficient data available

718 M. HERNÁNDEZ-CONDE ET AL. Rev Esp Enferm Dig Table II. Baseline characteristics of patients (n = 191) Age (years) 55 (24-74) Sex (%) (M:F) 75.4: 24.6 Etiology n (%) HCV 93 (48.7%) Alcohol 47 (24.6%) Autoimmune disease/cholestatic 16 (8.4%) HBV 8 (4.2%) Others 27 (14.1%) Child-Pugh A 80 (41.9%) B 68 (35.6%) C 43 (22.5%) MELD (mean) (SD) 15 (6) Previous decompensated n (%) Ascitis 116 (61.4%) Hepatic encephalopathy 65 (34.4%) Upper gastrointestinal bleeding 48 (25.4%) SBP 27 (14.3%) HCC 92 (48.9%) Analytical baseline mean (SD) Creatinine (mg/dl) 1.04 (0.9) Albumin (g/dl) 3.4 (0.7) Bilirrubin (mg/dl) 3.6 (4.3) ALT/AST (U/L) 98 (247)/178 (1,130) Alkaline phosphatase (U/L) 161 (130) GGT (U/L) 136 (159) Platelets (10E3/microL) 93 (52) Prothrombin activity (%) 65 (18) aptt (seg) 41 (9) Table III. Transplant characteristics Duration of transplantation in hours (SD) 6:15 (1:54) Red cell concentrates (mean) (SD) 7 (9) Bags of plasma (mean) (SD) 12 (11) Pools of platelets (mean) (SD) 3 (5) Bags of cryoprecipitate (mean) (SD) 0.01 (0.1) novo. The patients had the following Yerdel classifications: 12 patients (66.6%) had PVT type I, 3 patients (16.7%) had type II and 3 patients (16.7%) had type III. Thrombectomy was performed during LT on all patients found to have PVT. PVT was diagnosed by an imaging test prior to LT in 6 of the 18 patients (33.3%), 2 patients (11.1%) by DU and 4 patients (22.2%) by CT scan. All patients with PVT had a DU in the last 6 months before LT (0-44) and 90 patients (47.1%) had an abdominal-ct scan performed 6 month before the LT (0-45). Ten of the 18 patients with a PVT had an abdominal ultrasound in the 3 months prior to LT, resulting in only one patient being diagnosed with PVT. Patients who didn t undergo a DU were followed up with a CT or MRI scan. Pre-LT-related factors were evaluated as potential factors associated with the presence of PVT in the explanted liver. Results are described in table IV. It was found that the baseline factors which were significantly related to the presence of PVT in the explanted liver were: SBP (present in 33.3% of patients with PVT [n = 6] vs 12.6% of patients [n = 21] without PVT; p = 0.02), lower levels of albumin (mean baseline level of 3.1 g/dl in patients with PVT vs 3.4 g/dl in patients without PVT; p = 0.04). Although the MELD score was higher in PVT patients, it was not statistically significant (16.5 vs 14.9; p = 0.3). PVT patients required more transfusions of blood components, but the difference was not statistically significant (Table V). Moreover, the surgery time was similar in both groups (6:11 h in patients without PVT vs 6:15 h in patients with PVT; p = 0.8). When compared according to the Yerdel classification, similar results were observed for patients with grade I and those with grade II/III. However, patients with severe grades of PVT had longer surgery times than those who had less severe PVT (7:07 h vs 6:09 h; p = 0.1) Two patients (11.1%) had previous thrombosis (subclavian vein thrombosis and thrombosis of a temporal branch of the central vein in the retina). None of the patients were treated with anticoagulants before LT. After LT, all patients received low molecular weight heparin for 7 days and vitamin K antagonist (acenocumarol) for 6 months. Currently, 4 patients (22.2%) are treated with acenocumarol and 4 patients (22.2%) with acetylsalicylic acid (100 mg per day). The median patient follow-up time from the LT to death or loss of follow-up was 42 months (range 0-113). During follow-up, 29 patients (15.2%) had post-lt vascular complications: 11 patients had hepatic arterial thrombosis, 9 patients had portal vein stenosis, 2 patients had inferior vena cava thrombosis, 1 patient had PVT, and 6 patients had other vascular complications. No differences between vascular complications were observed between patients with PVT and those without PVT in the explanted liver. Sixteen patients (8%) died within 30 days post-lt. Mortality at 30 days post-lt was higher in the PVT group, although the difference was not statistically significant (16.7% vs 8.8%; p = 0.3). The 1-year mortality risk was 15.2% (29 patients). Although the risk was higher in the PVT group (4 of 18 patients [22.2%] vs 25 of 173 patients [14.5%]; p = 0.4), although the difference did not reach statistical significance.

2016, Vol. 108, N.º 11 PREVALENCE AND OUTCOME OF PORTAL THROMBOSIS IN A COHORT OF CIRRHOTIC PATIENTS 719 UNDERGOING LIVER TRANSPLANTATION Table IV. Factors related to the presence of TP in the explanted liver PVT No PVT p Age (years) (SD) 53 (5) 56 (9) 0.3 Sex (%) (M:F) 77.8:22.2 75.4:24.6 0.8 Etiology n (%) 0.13 HCV 9 (50%) 83 (49.7%) Alcohol 2 (11.1%) 44 (26.3%) Autoimmune disease/cholestatic 1 (5.6%) 14 (8.4%) HBV 2 (11.1%) 5 (3%) Other 4 (22.3%) 21 (12.6) Child-Pugh 0.4 A 7 73 B 8 51 C 2 36 MELD (mean) (SD) 16.5 (4.7) 14.9 (6.3) 0.3 Previous decompensated n (%) Ascitis 13 (72.2%) 100 (59.9) 0.3 Hepatic encephalopathy 8 (44.4) 56 (33.5) 0.4 Upper gastrointestinal bleeding 6 (33.3) 42 (25.1) 0.45 SBP 6 (33.3) 21 (12.6) 0.02 HCC 9 (50) 82 (49.1) 0.9 Analytical baseline mean (SD) Creatinine(mg/dl) 1.3 (1.7) 1 (0.8) 0.1 Albumin (g/dl) 3.1 (0.9) 3.4 (0.6) 0.05 Bilirrubin(mg/dl) 3.1 (1.9) 3.7 (4.5) 0.5 ALT/AST(U/L) 119 (277)/80 (63) 97 (247)/190 (1,200) 0.7/0.7 Alkaline phosphatase 107 (33) 167 (136) 0.07 GGT (U/L) 90 (83) 140 (166) 0.2 Platelets (10E3/microL) 86 (54) 94 (51.6) 0.5 Prothrombin activity (%) 59 (15) 66 (18) 0.1 aptt (seg) 37.5 (4.3) 41.2 (9.0) 0.1 Table V. Transfusion of blood components PVT No PVT p Red cell concentrates N 9 7 0.6 Platelet pools N 4 3 0.5 Bags of plasma N 15 12 0.3 DISCUSSION The prevalence of PVT in our cohort of patients was 9.4%, which is consistent with previous observations (3,12,13). In our cohort, patients with PVT had lower albumin levels and platelet counts and higher creatinine levels than those without PVT. PVT patients also had higher MELD scores. However, only the lower levels of albumin were statistically significant, probably due to the low prevalence of events in our series. Therefore, advanced liver disease appears to be a predictive factor for the development of PVT. Moreover, we show that the presence of previous SBP was statistically significant when associated with the presence of PVT in the explanted liver, which had not been described previously, and is probably related to advanced liver disease as well. In our study, the low diagnostic yield of imaging tests with regards to the diagnosis of PVT prior to LT was striking. Only 5 patients were diagnosed by CT scan and 2 with DU, and only 1 patient was diagnosed by both methods over-

720 M. HERNÁNDEZ-CONDE ET AL. Rev Esp Enferm Dig lapped. Pre-LT diagnosis was very low (33.3%) when a DU and/or an abdominal CT scan were used. This could be due to the fact that the median time between the completion of the DU and the LT was not excessively large. In our opinion, the follow up should be shortened in order to allow a short time interval between the imaging technique and the LT. PVT patients required more plasma transfusion units, as has been mentioned in other studies (1,14), which may be due to thrombocytopenia and advanced liver disease. Surgery times were similar in both groups but this could be related to the fact that most of the PVTs were type I and II (Yerdel classification), and therefore surgeries were not excessively complicated. However, if we consider severe grades of PVT, surgery times were higher. With regard to post-lt survival, mortality at 30 days post-lt in patients with PVT was higher, although the difference was not statistically significant, which is consistent with the data provided in other studies (15,16). This may be related to the fact that partial PVTs are more frequent than complete PVTs, and due to the small sample size in our study. Notwithstanding existing evidence in favor of avoiding thrombosis progression, guidelines before 2014 did not comprise treatment strategies for the management of patients on the waiting list for LT. In conclusion, in our study albumin and SBP were pre- LT factors associated with PVT. The 30-day mortality was two-fold higher in patients with PVT. The presence of PVT may have implications for morbidity and mortality in the short term, in particular with regards to complete PVT. REFERENCES 1. Yerdel MA, Gunson B, Mirza D, et al. 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