DOI:10.2214/AJR.04.1258
AJR 2005; 185:1558-1570
© American Roentgen Ray Society
Early Postoperative Hepatic Sonography as a Predictor of Vascular and Biliary Complications in Adult Orthotopic Liver Transplant Patients
Lawrence N. Uzochukwu1,
Edward I. Bluth1,
Dana H. Smetherman1,
Laurie A. Troxclair1,
George E. Loss, Jr.2,
Ari Cohen2 and
James D. Eason2
1 Department of Radiology, Ochsner Clinic Foundation, 1514 Jefferson Hwy., New
Orleans, LA 70121.
2 Section of Abdominal Transplantation, Multi-Organ Transplant Center, Ochsner
Clinic Foundation, New Orleans, LA 70121.
Received September 28, 2004;
accepted after revision December 6, 2004.
Address correspondence to E. I. Bluth.
Abstract
OBJECTIVE. Our objective was to quantitatively assess the value of
early posttransplantation hepatic artery resistive indexes in predicting
vascular and nonvascular complications in adult orthotopic liver transplant
(OLT) patients.
MATERIALS AND METHODS. Between 1999 and 2001, 110 consecutive adults
received grafts. Doppler sonographic graft evaluations measured main, right,
and left resistive indexes within 24 to 48 hr after surgery (normal resistive
index cutoff, 0.6). Clinical, operative, procedural, and radiologic reports
were reviewed for vascular and biliary complications. Frequency, Student's
t test, logistic, and regression statistical analyses were
performed.
RESULTS. even patients (6.4%) had vascular complications, including
two (1.8%) hepatic artery and two (1.8%) hepatic vein stenoses, one (0.9%)
hepatic vein thrombosis, two (1.8%) portal vein thromboses, and one (0.9%)
thrombosis and two (1.8%) stenoses of the inferior vena cava (IVC). In 19
patients (17.3%), biliary complications included anastomotic strictures and
leaks 1 week to 18 months after transplantation. In 11 patients (10%),
sonographically large hematomas required surgical evacuation. In grafts with
vascular complications or large hematomas, the mean early posttransplant main,
right, and left indexes were significantly lower (
0.6) than without these
complications (p < 0.01). In grafts with and without biliary
complications, mean early posttransplant main, right, and left indexes did not
differ significantly.
CONCLUSION. In adult OLT patients, low early posttransplant hepatic
artery resistive indexes were sensitive (100%) and specific (80%) predictors
for vascular complications (e.g., hepatic artery, portal vein, hepatic vein,
and IVC) but not for biliary complications. All patients with indexes less
than 0.6 within 24-48 hr after surgery should be monitored closely for
vascular complications.
Introduction
First performed in 1963 by Dr. Thomas Starzl, liver transplantation
has achieved a high success rate and is the treatment of choice for end-stage
liver disease. According to the United Network for Organ Sharing,
approximately 5,300 liver transplantations were performed in 2002
[1], making the liver second
only to the kidney as the most commonly transplanted solid organ. Improvements
in organ preservation, surgical technique, immunosuppressive regimens,
intensive care, and anesthetic management have resulted in increased survival
rates for liver transplant recipients
[2,
3].
However, there is an increasing disparity between the number of potential
recipients and available cadaveric donors. More than 17,000 potential liver
transplant recipients are waiting for grafts
[1]. Coupled with the financial
costs associated with liver transplantation, this disparity challenges health
providers to optimize organ use and improve patient outcomes. Postoperative
complications contribute significantly to morbidity and mortality of liver
transplant recipients [4].
Accordingly, early postoperative surveillance followed by rapid diagnostic and
therapeutic intervention should help minimize the impact of complications and
maximize both graft and patient survival
[5].
Vascular and nonvascular complications may occur after liver
transplantation. Vascular complications include stenosis or thrombosis of the
hepatic artery, hepatic vein, portal vein, and vena cava. Nonvascular
complications include biliary anastomotic leaks and strictures, fluid
collections, abscesses, and large hematomas. Of all vascular complications,
those involving the hepatic artery are the most serious, with
retransplantation required in as many as 75% of patients experiencing hepatic
artery thrombosis [6]. Early
detection of hepatic artery stenosis or thrombosis allows early
revascularization and possible graft salvage
[7].
Color Doppler sonography is routinely used at our institution to monitor
liver allografts because it is noninvasive, portable, and inexpensive
[8]. The utility of a low
arterial resistive index value as an indicator of increased diastolic flow and
decreased distal peripheral vascular resistance is well established
[9]. A low hepatic artery
resistive index is a reliable predictor of hepatic artery thrombosis and
stenosis
[8-10].
However, it remains unknown whether hepatic artery resistive indexes can
predict nonvascular complications or venous vascular complications involving
the portal vein, hepatic vein, or inferior vena cava (IVC).
In this retrospective study, we attempted to quantitatively analyze the
relationship between early postoperative hepatic artery resistive indexes and
the occurrence of various vascular and nonvascular complications in adult
orthotopic liver transplant (OLT) patients.
Materials and Methods
This study was approved by our institutional review board.
Study Population
The study group included 110 consecutive patients who underwent OLT between
1999 and 2001. This group consisted of 71 males and 39 females with a mean age
of 50.3 years (range, 17-71 years).
Indications for OLT are listed in Table
1. Chronic viral hepatitis and alcoholic cirrhosis were the causes
for end-stage liver disease in more than 60% of patients studied. Several
patients underwent OLT for more than one indication. A standard liver
transplantation surgical technique was used with caval replacement. After
vascular exclusion and excision of the native liver, the donor liver was
brought to the operative field and four vascular anastomoses were performed in
the following order: suprahepatic donor vena cava to recipient suprahepatic
vena cava, infrahepatic donor vena cava to recipient infrahepatic vena cava,
donor portal vein to recipient portal vein, and donor hepatic artery to
recipient hepatic artery. The liver was reperfused after the portal vein
anastomosis was completed. Venovenous bypass and biliary T tubes were not
used.
Doppler Sonography Measurements
All study patients were examined by color Doppler sonography within 24-48
hr of surgery using a 2.0- to 5.0-MHz transducer (5000 C5-2 curvilinear and
P3-2 phased-array transducers, Philips Medical Systems). Examinations were
repeated in patients after necessary interventions. The color Doppler
sonography examination included a real-time morphologic evaluation of the
liver parenchyma and color mapping of the hepatic artery, portal vein, hepatic
veins, and IVC. Spectral analyses of the hepatic arteries were performed to
measure peak systolic and diastolic velocities. Spectral analyses for the
hepatic vein, portal vein, and IVC were also obtained. The hepatic artery
resistive index was calculated according to the formula:
 |
Data Acquisition and Analysis
A retrospective analysis of clinical, operative, procedural, and radiologic
reports was performed to determine the incidence of vascular complications,
biliary complications, and large hematomas after liver transplantation
surgery. The presence of a complication was confirmed by hepatic digital
subtraction angiography, cholangiography, or surgery. Only large hematomas
requiring operative evacuation were included as complications. A low hepatic
artery resistive index was defined as less than or equal to 0.6. Statistical
significance was defined as a p value of less than 0.05. Frequency
analyses, Student's t test, and logistic regression were used to
analyze the differences in mean hepatic artery resistive indexes in patients
with and without vascular complications, biliary complications, or large
hematomas.
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Fig. 1A —Patient with hepatic artery stenosis. Color Doppler sonograms
show low-resistance flow patterns in main (A), right (B), and
left (C) hepatic arteries in orthotopic liver transplant graft with
hepatic artery stenosis.
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Fig. 1B —Patient with hepatic artery stenosis. Color Doppler sonograms
show low-resistance flow patterns in main (A), right (B), and
left (C) hepatic arteries in orthotopic liver transplant graft with
hepatic artery stenosis.
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Fig. 1C —Patient with hepatic artery stenosis. Color Doppler sonograms
show low-resistance flow patterns in main (A), right (B), and
left (C) hepatic arteries in orthotopic liver transplant graft with
hepatic artery stenosis.
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Results
Among the 110 OLT patients studied, seven patients (6.4%) had vascular
complications; 11 (10%), postoperative hematomas; and 19 (17.3%), biliary
complications. Vascular complications included two hepatic artery stenoses,
three hepatic vein stenoses, one hepatic vein thrombosis, two portal vein
thromboses, one IVC thrombosis, and two IVC strictures
(Table 2). Of these seven
patients, patient 1 was diagnosed with hepatic artery stenosis by digital
subtraction angiography 2 weeks after the OLT and subsequently underwent
surgical revision of the vascular anastomosis (Figs.
1A,
1B,
1C, and
1D). Patient 2 was diagnosed
with hepatic artery stenosis by digital subtraction angiography 4 months after
the OLT and subsequently underwent angioplasty. Patient 3 was diagnosed with
hepatic vein stenoses by digital subtraction angiography 6 months after the
OLT and subsequently underwent angioplasty (Figs.
2A,
2B,
2C, and
2D). Patient 4 was diagnosed
with hepatic vein stenosis by digital subtraction angiography 8 months after
the OLT and subsequently underwent angioplasty (Figs.
3A,
3B,
3C,
3D,
3E,
3F,
3G,
3H,
3I,
3J, and
3K). Patient 5 was diagnosed
with concomitant hepatic vein thrombosis, portal vein thrombosis, and IVC
thrombosis by color Doppler sonography 2 months after the OLT and subsequently
underwent surgical thrombectomy (Figs.
4A,
4B,
4C,
4D,
4E,
4F, and
4G). Patient 6 was diagnosed
with portal vein thrombosis by color Doppler sonography on postoperative day 1
after the OLT and subsequently underwent surgical thrombectomy, but died
shortly thereafter (Figs. 5A,
5B,
5C, and
5D). Patient 7 was diagnosed
with a stenosis of the intrahepatic segment of the IVC by digital subtraction
angiography 12 months after OLT and subsequently underwent angioplasty (Figs.
6A,
6B,
6C,
6D,
6E,
6F,
6G, and
6H). OLT grafts for patients
1-5 and 7 were successfully salvaged after interventions. The graft salvage
rate was 86% (with the exclusion of patient 5).
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TABLE 2 : Early Posttransplantation Main, Right, and Left Hepatic Artery
Resistive Indexes Stratified by Category of Vascular Complication for
Individual Patients
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Fig. 2A —Patient with hepatic vein stenosis. Color Doppler sonograms
show low-resistance flow patterns in main (A) and left (B)
hepatic arteries in orthotopic liver transplant graft with hepatic vein
stenosis.
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Fig. 2B —Patient with hepatic vein stenosis. Color Doppler sonograms
show low-resistance flow patterns in main (A) and left (B)
hepatic arteries in orthotopic liver transplant graft with hepatic vein
stenosis.
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Fig. 3A —Patient with hepatic vein stenosis. Color Doppler sonograms
show low-resistance flow patterns in main (A), right (B), and
left (C) hepatic arteries in orthotopic liver transplant (OLT) graft
with hepatic vein stenosis.
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Fig. 3B —Patient with hepatic vein stenosis. Color Doppler sonograms
show low-resistance flow patterns in main (A), right (B), and
left (C) hepatic arteries in orthotopic liver transplant (OLT) graft
with hepatic vein stenosis.
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Fig. 3C —Patient with hepatic vein stenosis. Color Doppler sonograms
show low-resistance flow patterns in main (A), right (B), and
left (C) hepatic arteries in orthotopic liver transplant (OLT) graft
with hepatic vein stenosis.
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Fig. 3D —Patient with hepatic vein stenosis. Color Doppler sonograms
show normal hepatofugal blood flow in main hepatic vein (D and
F) and abnormal hepatopedal blood flow in right hepatic vein (E
and F) of OLT graft with hepatic vein stenosis. In F, RHV =
right hepatic vein, MHV = main hepatic vein.
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Fig. 3E —Patient with hepatic vein stenosis. Color Doppler sonograms
show normal hepatofugal blood flow in main hepatic vein (D and
F) and abnormal hepatopedal blood flow in right hepatic vein (E
and F) of OLT graft with hepatic vein stenosis. In F, RHV =
right hepatic vein, MHV = main hepatic vein.
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Fig. 3F —Patient with hepatic vein stenosis. Color Doppler sonograms
show normal hepatofugal blood flow in main hepatic vein (D and
F) and abnormal hepatopedal blood flow in right hepatic vein (E
and F) of OLT graft with hepatic vein stenosis. In F, RHV =
right hepatic vein, MHV = main hepatic vein.
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Fig. 3J —Patient with hepatic vein stenosis. and K, Angiogram
shows high-grade stenosis (J) and subsequent restoration of blood flow
with minimal residual narrowing (K) of intrahepatic IVC after balloon
venoplasty.
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Fig. 3K —Patient with hepatic vein stenosis. Angiogram shows
high-grade stenosis (J) and subsequent restoration of blood flow with
minimal residual narrowing (K) of intrahepatic IVC after balloon
venoplasty.
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Fig. 4A —Patient with thrombosis of portal vein, hepatic vein, and
inferior vena cava (IVC) and IVC stenosis. Color Doppler sonograms show
high-resistance flow patterns in main (A), right (B), and left
(C) hepatic arteries in orthotopic liver transplant graft with
surgically proven thrombosis of IVC, portal vein, and hepatic vein.
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Fig. 4B —Patient with thrombosis of portal vein, hepatic vein, and
inferior vena cava (IVC) and IVC stenosis. Color Doppler sonograms show
high-resistance flow patterns in main (A), right (B), and left
(C) hepatic arteries in orthotopic liver transplant graft with
surgically proven thrombosis of IVC, portal vein, and hepatic vein.
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Fig. 4C —Patient with thrombosis of portal vein, hepatic vein, and
inferior vena cava (IVC) and IVC stenosis. Color Doppler sonograms show
high-resistance flow patterns in main (A), right (B), and left
(C) hepatic arteries in orthotopic liver transplant graft with
surgically proven thrombosis of IVC, portal vein, and hepatic vein.
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Fig. 4D —Patient with thrombosis of portal vein, hepatic vein, and
inferior vena cava (IVC) and IVC stenosis. Color flow images show absence of
blood flow within IVC and main portal vein, and distention by thrombus. MHV =
main hepatic vein.
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Fig. 4E —Patient with thrombosis of portal vein, hepatic vein, and
inferior vena cava (IVC) and IVC stenosis. Color flow images show absence of
blood flow within IVC and main portal vein, and distention by thrombus. MHV =
main hepatic vein.
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Fig. 4G —Patient with thrombosis of portal vein, hepatic vein, and
inferior vena cava (IVC) and IVC stenosis. Angiogram shows restoration of
normal blood and improvement in caliber at junction of IVC and right
atrium.
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Fig. 5A —Patient with portal vein thrombosis. Color Doppler sonogram
shows low-resistance flow patterns in main (A) and right (B)
hepatic arteries in orthotopic liver transplant graft with surgically proven
portal vein thrombosis.
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Fig. 5B —Patient with portal vein thrombosis. Color Doppler sonogram
shows low-resistance flow patterns in main (A) and right (B)
hepatic arteries in orthotopic liver transplant graft with surgically proven
portal vein thrombosis.
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Fig. 5C —Patient with portal vein thrombosis. Color Doppler sonograms
show absence of blood flow within main portal vein (C) and normal blood
flow within adjacent main hepatic artery (D) in this patient with
surgically proven portal vein thrombosis.
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Fig. 5D —Patient with portal vein thrombosis. Color Doppler sonograms
show absence of blood flow within main portal vein (C) and normal blood
flow within adjacent main hepatic artery (D) in this patient with
surgically proven portal vein thrombosis.
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Fig. 6A —Patient with inferior vena cava (IVC) stenosis. Color Doppler
sonograms show low-resistance flow patterns in main (A), right
(B), and left (C) hepatic arteries in orthotopic liver
transplant graft with IVC stenosis.
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Fig. 6B —Patient with inferior vena cava (IVC) stenosis. Color Doppler
sonograms show low-resistance flow patterns in main (A), right
(B), and left (C) hepatic arteries in orthotopic liver
transplant graft with IVC stenosis.
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Fig. 6C —Patient with inferior vena cava (IVC) stenosis. Color Doppler
sonograms show low-resistance flow patterns in main (A), right
(B), and left (C) hepatic arteries in orthotopic liver
transplant graft with IVC stenosis.
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The seven patients with vascular complications had mean main, right, and
left hepatic artery resistive index values of 0.52 ± 0.18 (SD), 0.49
± 0.17, and 0.47 ± 0.19, respectively
(Table 3). Patients without
vascular complications had mean main, right, and left hepatic artery resistive
indexes of 0.72 ± 0.17, 0.72 ± 0.19, and 0.72 ± 0.17,
respectively (Table 3).
Patients with vascular complications showed significantly lower mean hepatic
artery resistive indexes compared with those without vascular complications
(p < 0.05) (Table
3).
One patient (patient 5, Table
2) had concomitant thromboses of the hepatic vein, portal vein,
and IVC, and a stenosis at the junction of the right atrium and IVC. This
patient was therefore initially included in three vascular complication
categories. This was also the only patient with a vascular complication who
had hepatic artery resistive indexes greater than 0.6. This exception noted,
all other patients with vascular complications involving the hepatic artery,
hepatic vein, portal vein, or IVC had main, right, and left hepatic artery
resistive indexes that were less that 0.6.
Of the 110 patients in the study group, 27 had a hepatic artery resistive
index of less than 0.6 in the early posttransplant period. Of these 27
patients with low early posttransplant hepatic artery resistive indexes, six
had vascular complications. Conversely, of all patients with hepatic artery
resistive indexes greater than 0.6 in the early posttransplant period, only
one (patient 5, Table 2) had a
vascular complication. Therefore, a hepatic artery resistive index of less
than or equal to 0.6 in the early postoperative period had a sensitivity of
85% and a specificity of 80% for the detection of a vascular complication
involving the hepatic artery, hepatic vein, portal vein, or IVC. Excluding
patient 5, whose case was confounding because of multiple vascular
complications, the sensitivity increased from 85% to 100% while the
specificity remained 80%.
Eleven patients had sonographically apparent large hematomas that were
surgically evacuated. These patients with large hematomas had mean main,
right, and left hepatic artery resistive indexes of 0.61 ± 0.22, 0.57
± 0.23, and 0.59 ± 0.21, respectively (Tables
3 and
4). Patients without large
hematomas had mean main, right, and left hepatic artery resistive indexes of
0.75 ± 0.17, 0.72 ± 0.18, and 0.72 ± 0.17, respectively
(Table 3). Patients with large
hematomas had significantly lower mean hepatic artery resistive indexes
compared with those without large hematomas (p < 0.02)
(Table 3). Color Doppler
sonography examinations were not consistently performed in the preoperative
periods after surgical evacuations to determine if there was a significant
change in the hepatic artery resistive indexes, as would be expected.
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TABLE 4 : Early Posttransplantation Main, Right, and Left Hepatic Artery
Resistive Indexes and Corresponding Hematoma Size for Patients with
Hematomas
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The 19 cases of biliary complications included two patients with biliary
leaks that occurred within 1 week postoperatively and 17 patients with biliary
strictures that occurred between 1 and 16 months postoperatively
(Table 5). Most strictures
occurred at the anastomosis. The 19 patients with biliary complications had
mean main, right, and left hepatic artery resistive indexes of 0.74 ±
0.14, 0.70 ± 0.15, and 0.71 ± 0.16, respectively
(Table 3). Patients without
biliary complications had mean main, right, and left hepatic artery resistive
indexes of 0.74 ± 0.19, 0.71 ± 0.20, and 0.70 ± 0.19,
respectively (Table 3). No
significant difference was found between the mean hepatic artery resistive
indexes in patients with biliary complications compared with those without
biliary complications (p > 0.5)
(Table 3). Two patients in the
biliary complication group had low initial hepatic artery resistive indexes,
but these patients had concomitant vascular complications.
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TABLE 5 : Early Posttransplantation Main, Right, and Left Hepatic Artery
Resistive Indexes and Corresponding Timeline for Patients with Biliary
Complications
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Discussion
Hepatic artery stenosis reportedly occurs in 4-5% of OLT cases, and hepatic
artery thrombosis occurs in 2-12% of cases
[4]. Both hepatic artery
stenosis and hepatic artery thrombosis can occur early in the postoperative
period or remote from the time of transplantation
[10]. Causes for hepatic
artery stenosis include surgical technique, intraoperative trauma or clamp
injury, anastomotic ischemia, and graft rejection. Hepatic artery thrombosis
is most often caused by a low-flow state or anastomotic stenosis
[4,
11].
Restriction or obstruction of hepatic artery perfusion can be particularly
deleterious in a liver transplant graft, because the normal collateral
vascular pathways and regulatory neurologic pathways are disrupted during the
normal allograft explant and implant procedures
[7]. This makes the hepatic
artery the major source of oxygenated blood to the liver allograft parenchyma
and biliary tree and makes the allograft particularly susceptible to the
ischemic states of hepatic artery stenosis or hepatic artery thrombosis.
Nevertheless, the clinical presentation of hepatic artery stenosis or hepatic
artery thrombosis is not very specific and the diagnosis is often difficult to
make. Consequently, postoperative surveillance imaging has become a frequently
used diagnostic tool. While digital subtraction angiography is the gold
standard for diagnosing hepatic artery stenosis and hepatic artery thrombosis,
color Doppler sonography, because of its noninvasive nature and relatively low
cost, has become the most widely used technique for monitoring transplant
allografts, particularly for hepatic artery-related complications
[7,
11]. Digital subtraction
angiography is most often performed after a positive color Doppler sonography
to confirm the diagnosis and to effect a therapeutic intervention.
Dodd et al. [9] reported
that color Doppler sonography findings, including an abnormally low hepatic
artery resistive index (< 0.5), long systolic acceleration time (
0.08), elevated peak velocity, and the absent arterial flow, had a 97%
sensitivity and 64% specificity for diagnosing hepatic artery thrombosis and
severe hepatic artery stenosis. De Gaetano et al.
[11] reported that the
presence of intraparenchymal tardus-parvus waveforms improved the diagnostic
accuracy of color Doppler sonography for severe hepatic artery disease,
although this finding could not distinguish hepatic artery thrombosis from
hepatic artery stenosis. Both patients in our study with angiographically
proven hepatic artery stenosis (patients 1 and 2) showed low early
posttransplantation hepatic artery resistive indexes. Patient 1 showed
tardus-parvus waveforms on the initial postoperative color Doppler sonography,
whereas patient 2 showed tardus-parvus waveforms on a follow-up color Doppler
sonography examination immediately preceding angioplasty 4 months after
transplantation. Patients with vascular complications involving the hepatic
vein, portal vein, and IVC did not show tardus-parvus waveforms on initial or
follow-up color Doppler sonography examinations. Therefore, the presence of a
low hepatic artery resistive index and tardus-parvus waveforms may be
suggestive of a vascular complication specifically involving the hepatic
artery, such as hepatic artery stenosis.
Hepatic vein stenosis, hepatic vein thrombosis, and IVC thrombosis are rare
complications, occurring in 1-2% of liver transplant patients and usually
resulting from vessel torsion or extrinsic compression
[4,
12]. Both patients in our
study with hepatic vein stenosis and one of the patients with intrahepatic IVC
stenosis showed low early posttransplantation hepatic artery resistive index
measurements and underwent angiographic venoplasties.
Portal vein thrombosis is also an uncommon complication, occurring in 3% of
liver transplant patients [4,
12]. In a study of 35
nontransplant patients with proven partial or occlusive portal vein
thrombosis, Platt et al. [13]
found that 27 of the 35 patients had significantly lower mean hepatic artery
resistive indexes than patients without portal vein thrombosis. Furthermore,
12 of these 27 patients had mean hepatic artery resistive indexes that were
below 0.5. These 12 patients had acute occlusive portal vein thrombosis. This
phenomenon of acute occlusive portal vein thrombosis associated with low
hepatic artery resistive indexes in the nontransplant setting appears to hold
true for portal vein thrombosis encountered in livers posttransplantation.
Both patients in our study with portal vein thrombosis also showed low early
posttransplantation hepatic artery resistive index measurements. Accordingly,
a hepatic artery resistive index may serve as a valuable screening tool for
posttransplant portal vein thrombosis.
A low hepatic artery resistive index in the early posttransplantation
period was also associated with the presence of large hematomas. This possibly
resulted from the hematoma compressing all of the vascular structures,
including the hepatic artery, although confirmatory postevacuation duplex
examinations were not consistently performed.
Interestingly, our study showed no association between low hepatic artery
resistive indexes and biliary complications. This is surprising, because the
biliary anastomosis and the bile ducts in general are particularly sensitive
to changes in hepatic arterial blood flow. The low incidence of hepatic artery
stenosis/thrombosis in our series and the early intervention afforded by color
Doppler sonography surveillance and detection likely account for this lack of
association.
There was also a high concordance among hepatic artery resistive indexes
measured for the main, right, and left hepatic arteries. This suggests that a
hepatic artery resistive index measurement for the main hepatic artery may
preclude the necessity of obtaining hepatic artery resistive index
measurements for the right and left hepatic arteries except in patients with
unusual anatomy, such as a replaced right hepatic artery.
In our experience, vascular complications after OLT are rare (6.4%).
However, the vascular complications we encountered included not only hepatic
artery stenosis but also hepatic vein stenosis, hepatic vein thrombosis,
portal vein thrombosis, and IVC stenosis and thrombosis. Patients with
vascular complications in all these categories showed low early
posttransplantation hepatic artery resistive indexes. For our study, we
selected a low hepatic artery resistive index cutoff of less than or equal to
0.6 instead of less than 0.5 to screen for vascular complications not limited
to the hepatic artery, but also including the hepatic vein, portal vein, and
IVC. We think that using this new parameter will enable sonologists to
diagnose all vascular complications and not just those involving the hepatic
artery. Our data suggest that a low hepatic artery resistive index in the
early posttransplantation period is a sensitive (100%) and specific (80%)
predictor of arterial and venous vascular complications. Consequently, all
vascular structures need to be carefully interrogated as part of the routine
postoperative evaluation.
One shortcoming of our study is the small number of vascular complications
encountered, which somewhat limits the power of the statistical analyses. A
larger study with a longer follow-up period is needed to corroborate our
finding that low hepatic artery resistive indexes are associated with both
arterial and venous vascular complications.
Vascular complications after liver transplantation can be catastrophic.
However, early recognition of these complications can facilitate prompt
intervention and optimize graft survival and patient outcomes. Hence, all
patients with early posttransplantation hepatic artery resistive indexes below
0.6 should be monitored closely for vascular complications. We recommend that
color Doppler sonography be part of routine perioperative liver allograft
surveillance to identify patients at high risk for arterial or venous vascular
complications. A low early posttransplantation hepatic artery resistive index
is a sensitive and specific predictor of both venous and arterial vascular
complications in adult OLT patients. Moreover, low hepatic artery resistive
indexes are associated with large intraabdominal hematomas but are not
predictive of postoperative biliary complications.
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Abstract
Introduction
