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INTRODUCTION at a single institution was undertaken. Patients with complete
mesenteric venous thrombosis were excluded from LT, and
[1]
In 1985, Shaw et al. reported the first successful cases of all other patients were included in the analysis. Pre-operative
liver transplantation (LT) in the setting of recipient portal patient demographics and clinical status were evaluated to
vein thrombosis (PVT). PVT was once considered an absolute identif y any potential risk factors for PVT. Routine imaging at
contraindication to LT due to the considerable risk of our center consists of liver Doppler ultrasound (US) and a cross-
intraoperative mortality and the technical difficulty of the sectional imaging either a triple phase computed tomography
[2]
operation. Advancements in operative technique, greater (CT) or an Eovist magnetic resonance imaging (MRI). All imaging
experience with the operation, and improved intra-operative was reviewed by a multidisciplinary conference held weekly
anesthesia management have now made LT in patients with with all surgeons, hepatologists, body imaging radiologist,
PVT increasingly common. [3] and interventional radiologists present. Interval imaging after
listing a patient for transplantation consists of the US every 6
It is estimated that the prevalence of PVT in cirrhotic patients months. In patients with malignancy, contrasted CT, or MRI is
who are the candidates for LT ranges from 5% to 26%. Despite done every 3 months until LT. The effectiveness of diagnosing
[4]
its prevalence, the understanding of PVT in the context of LT PVT pre-LT, when PVT was later identified at LT, was evaluated
remains incomplete. Furthermore, the impact of PVT on the for US, CT, MRI, and retrograde portal venography (RPV). Patient
natural history and progression of cirrhosis is uncertain. and graft survival were considered as primary endpoints.
[5]
Although there is no clear evidence that PVT leads to further Blood utilization, LOS, and overall morbidity (Clavien grade II
deterioration of liver function in advanced cirrhosis, this is or greater) were used as surrogates of resource utilization.
[14]
often a common assumption or observation. Furthermore, These were our secondary endpoints.
PVT may be a source of technical difficulties in the particular
setting of transplantation leading to a negative impact on Statistical analysis
outcomes. To date, the evidence regarding the effect of PVT Continuous variables were compared between the groups
[4]
on LT outcomes is mixed.
using Student’s t-test, categorical variables were compared
using Chi-square test, and the serial values were compared
The mixed evidence exists regarding the risk factors for PVT, using analysis of variance (ANOVA). Kaplan-Meier with
as well as the utility of preoperative imaging protocols in
[6-9]
identifying the patients with, or at risk for PVT. As a result, log-rank analysis of actuarial patient and graft survival
it is estimated that more than 50% of patients with PVT remain were calculated. LOS and PRBC were analyzed using
undiagnosed until the time of surgery, even when a rigorous ANOVA. Overall morbidity (Clavien grade II or greater)
pre-operative screening protocol is utilized. [10,11] In addition, was compared between the groups by Chi-square analysis.
the full extent of PVT is not evident until the LT operation. Pre-operative characteristics that were significant on
[7]
Since surgeons are unable to rely on imaging, pre-operative univariate analysis were evaluated by logistic regression
planning according to the severity of thrombosis remains to identify any potential risk factors for PVT. Multivariate
difficult. However, as is the case with known PVT, it is still survival analysis was done with a Cox proportional hazards
undetermined whether or how the occult, or incorrectly model, and independent predictors of LOS and PRBC were
graded PVT, discovered at LT, impacts outcome. analyzed by multivariate analysis of covariance.

Regarding the resource utilization in LT, it has been shown RESULTS
that longer length of stay (LOS) and higher cost of care are
associated with increased severity of illness, increased number Of 216 patients undergoing cadaveric LT, 30 (13.8%) patients
of procedures performed, and younger age. Resource had PVT at the time of operation. Two hundred and five
[12]
utilization data specific to LT with PVT is limited. However, PVT patients had at least one diagnostic imaging study within
has been associated with longer operative times and increased 1-year of LT. Only, 7 of 30 patients with PVT (23.3%) had at
use of blood products. [13] least one positive imaging study suggestive of PVT pre-LT.
The sensitivity of imaging techniques ranged 4.8-50%, and the
Herein, an analysis of the risk factors for PVT and independent negative predictive value ranged 10.5-22.2% [Table 1].
predictors of survival were undertaken. We review the
commonly used modalities for detection of PVT, and the effects Analysis of perioperative variables for those patients with and
of an uncertain pre-operative diagnosis of PVT on survival without PVT revealed that there was a significantly higher model
and resource utilization as determined by blood utilization/ for end-stage liver disease (MELD) score (25.0 vs. 21.4, P = 0.049)
transfusion rate [packed red blood cell (PRBC)], LOS, and post- and age (57.8 vs. 53.8, P = 0.041) in those with PVT, although
operative morbidity at our institution. intensive care unit (ICU) status approached statistical significance
(30% vs. 15.6%, P = 0.07) [Table 2]. However, in our small
METHODS series, the only factor by logistic regression that significantly
predicted PVT was age [P = 0.037; hazard ratio (HR) = 0.95].
A retrospective analysis of 216 consecutive adult patients
undergoing cadaveric LT from January 2007 to December 2013 Overall 90-day, the patient and graft survivals were 90.7% and

Hepatoma Research | Volume 2 | Issue 2 | February 29, 2016 37