Document Type : Original Article
Authors
1 Department of Radiodiagnosis, Ain Shams University, Cairo, Egypt
2 Department of Surgery, Ain Shams University, Cairo, Egypt.
Abstract
The role of Doppler ultrasonography in monitoring the hepatic graft in the early post transplantation period
Maha K Abdel Ghaffar, MIJa; Mohamed Sobhy, MIJa;
MohamedAmin Nassef, MD; Mohamed Bahaa, MJJb
a) Department of Radiodiagnosis, Ain Shams University, Cairo, Egypt. b) Department of Surgery, Ain Shams University, Cairo, Egypt.
Purpose: To distinguish the alarming from the non-alarming signs during immediate postoperative Doppler ultrasonography (US) follow up for liver transplantation cases.
Patients and methods: From March 2012 to June 2013, 36 patients of post living related donor liver transplantation where followed up in the first month after liver transplantation and the US and Doppler US changes were recorded together with their laboratory data. When there were alarming Doppler US signs CT angiography was done to confirm vascular complications.
Results: 5 cases (13.8%) presented with hyperechoic segments due to segmental venous congestion, 12 cases {33.3%) showed raw surface collection, 15 cases (41.6%) presented with free peritoneal fluid and 18 cases (50%) had right pleural effusion. One patient (2.7%) presented with occluded hepatic artery and thrombectomy was done. 30 cases {83.3%) showed increased portal vein velocity The mortality was 8.3% seen in 3 cases, two of them (5.5%) suffered from 7th day syndrome presented with abrupt sharp decrease in portal flow and one case (2.7%) had a small graft size and presented with marked slowliness of the portal flow on Doppler study and a venous infarct on CT
Conclusion: The early monitoring of graft hemodynamic changes by Doppler sonography is of great importance as most of these changes revert to normal in the first postoperative week, however sharp decrease in arterial or portal flow indicates underlying grave vascular complications, some of them are correctable.
Introduction:
End-stage liver disease (ESLD) and (HCC) have become the main cause of mortality in our country in patients with hepatitis B or C vtruses.
Orthotopic liver transplantation (OLT) is
the only definitive treatment for patients with irreversible acute and chronic liver disease.l
Patients should be considered for liver transplantation if they have evidence of fulminant hepatic failure, a life-threatening systemic complication of liver disease, or a liver-based metabolic defect or, more commonly, cirrhosis with complications such as hepatic encephalopathy, ascites, hepatocellular carcinoma, hepatorenal syndrome, or bleeding caused by portal hypertension. While the complications of
cirrhosis can often be managed relatively effectively, they indicate a change in the natural history of the disease that should lead to consideration of liver transplantation.2
Ultrasonography (US) and Doppler examination is the preferred modality for postoperative imaging because it is portable, is readily available, and provides early detection of complications. Doppler US is used to detect treatable vascular complications and ensure graft survival. The first 24 hours after transplantation are referred to as the "hyperdynamic phase," in which the transplanted liver demonstrates disordered circulatory patterns and hemodynamic instability. The first postoperative Doppler US images are obtained fairly early on the first postoperative day, before surgical
Am-Shams] Surg 2014; 7(19):1-10
wounds have been closed. 1
The aim of our work is to highlight the alarming and non-alarming Doppler US findings in the immediate postoperative images, obtained when the effects of surgery are very recent. Most of these changes revert to normal in the first postoperative week; deterioration of transient changes requires further evaluation.
Methods:
During the period from March 2012 to June 2013, 36 adult patients (25 males, 9 females) ranging in age between 37 to 59 years with mean of 53.4 years underwent living related donor liver transplantation in Ain Shams University Specialized hospital (liver transplantation unit). Indication for transplantation was end stage liver disease for
27 cases and HCC in 9 cases. 7 of our patients
had chronic portal vein thrombosis of variable extent and for all successful thrombectomy was done during surgery Table (1).
Routine gray-scale US ofthe transplanted
liver was performed with detailed vascular Doppler US. During the first week, patients were examined daily using Doppler US, then every other day till the third week and twice weekly for the rest of the 1st three months. The examination was done using a 5 MHz curved array transducer LOGIQ
500 (GE, YokogawaMedical System Ltd,
Tokyo, Japan). All patients were examined in the supine position during quiet breathing. Doppler tracings of portal vein were obtained from the right branch of the portal vein in the case of right lobe graft and from umbilical portion of the portal vein in the case of left lobe graft. Doppler tracings of hepatic artery were obtained from the right hepatic artery in the case of right lobe graft and from the left hepatic artery in the case of left lobe graft. Veins of the graft were also examined.
During the Doppler US examination the
following were observed:
-Homogenicity of the graft which was affected by the effect of reperfusion edema and fluid stasis in the extracellular compartments.
-Presence of collections or free fluid in pleura or peritoneum.
-Patency of hepatic artery and its wave pattern demonstrated normally by rapid systolic upstroke with systolic acceleration time of less 80 msec and continuous diastolic flow, and RI which ranges normally from
0.55 to 0.8.
-Patency of portal vein presented normally by a centripetal direction of flow and a mean portal velocity of 58 em/sec at the anastomosis site.
-Patency of hepatic veins and its normal
triphasic wave pattern.
In cases of persistent abnormality in Doppler US study or ifthere were laboratory abnormality as increased level of SGOT, SGPT, bilirubin, INR and serum lactate with no significant Doppler explanation, diagnostic CT angiography was recommended.
Results:
36 patients after living related donor liver transplantation were examined daily during the first week using US and Doppler US, then every other day till the third week and twice weekly for the rest of the 1st three months Tables (2-3).
Five cases (13.8%) with segmental venous
congestion presented with hyperechoic segments and had increased levels of SGOT and SGPT in the first week Figure (1).
Twelve cases (33.3%) showed raw surface
collection, 15 cases (41.6%) presented with free peritoneal fluid and 18 cases (50%) had right pleural effusion Figure (2).
We had one patient with occluded hepatic
artery in day 2, he presented with shooting liver enzymes and increased serum lactate. Occluded hepatic artery was confirmed by 3D CT MIP (maximum intensity projection) and the patient was explored and a thrombus was found in hepatic artery at anastomotic site. Thrombus was removed, anastomosis was revised and patency was regained Figure (3).
The increased portal vein velocity was
detected in 30 patients (83.3%) and was noticed to be the most frequent abnormality seen in the early post-operative period however it declined gradually through the first month Figure (4).
Additionally 2 cases (5.5%) developed
Figure (1): /creased liver enzymes in day 3 after LT in a 50 years old male. Gray scale US shows congested hyperechoic area at segment VII of the graft.
Figure (3): Shooting liver enzymes with increased serum lactate in the second day after LT in a 53 years old male. A and B: 3D CT MIP showing abrupt occlusion of hepatic artery at the surgical anastomosis {arrow). C: Pulsed Doppler and D: Color Doppler showing patent hepatic artery after removal of thrombectomy.
what is known as 7th day syndrome in which the pmtal flow showed abrupt sharp decrease in day 7 reaching to less than 5 crn!s and unfortunately both patients died in day 8 and day 9. They showed shooting levels in SGOT and SGPT as well as bilimbin and INR.
We also had one patient (2.7%) who presented with slowliness of pmtal flow at day 7 reaching 18 cm/s with shooting levels
Figure (2): Organized haematoma in a
47 year old female. Gray scale US image obtained on the first day after LT shows organized collection (haematoma) at the raw surface of the graft.
Figure (4): Increased portal venous flow in a 56 years old male patient. Pulsed Doppler US obtained on the third day after LT shows increased portal venous velocity {162 em/ sec) due to presence of persistence portal hypertension before the surgery.
of SGOT, SGPT and bilimbin. CT was done because Doppler US alone could not explain the laboratmy abnmmalities and it showed a non-enhancing wedge shaped area around a patent tight hepatic vein. This area was a venous infarct that occUlTed despite patency of the tight hepatic vein due to the small size of the graft. The patient died on day 9
Figw·e(S).
Figure (5): Shooting liver enzymes with increased serum bilirubin in day 7 after LT in a 48 years old female patient. A: CT scan shows a wedge shaped infarction oriented around a patent right hepatic vein {arrow).B: CT scan shows patent graft artery {arrow), C: CT Shows patent portal vein {arrow), D: Pulsed Doppler study of the right hepatic vein showing its patency with triphasic flow.
Table (1): Patient's clinical presentation before liver transplantation.
Patient's clinical presentation |
Number |
Percentage |
End stage liver disease |
27 |
75% |
Hepatocellular carcinoma |
9 |
25% |
Table (2): Summary of ultrasonographic manifestations and the resu/1 of the patient's follow up.
US findings |
Number |
Percentage |
Sequence |
Congested segment |
5 |
13.8% |
Recovered |
Raw surface collection |
12 |
33.3% |
Recovered |
Free peritoneal fluid |
15 |
41.6 |
Recoverd |
Right sided pleural effusion |
18 |
50% |
Recoverd |
Table (3): Summary of Doppler manifestations and the resu/1 of the patient's follow up.
Doppler findings |
Number |
Percentage |
Sequence |
Occluded hepatic rutery |
1 |
2.7% |
Explored and patency regained |
Increased portal vein velocity |
30 |
83.3% |
Recovered |
Decreased pmtal velocity |
3 |
8.2% |
Died |
Discussion:
Angiography is the standa.I·d of reference for exploration in the assessment of hepatic vessels patency; it is an invasive technique
and requires intravenous administration of iodinated contrast, increasing the tisk of renal function impainnent, which is fi:equent dming the eru·ly postoperative period in liver
transplanted patients.3 DUS is the screening technique preferably used in the transplanted liver as it is a noninvasive procedure and very usefulness in the assessment of hepatic vessels patency.4
Routine gray-scale US of the transplanted liver is performed before detailed vascular Doppler US. It is fairly common for the effects of reperfusion edema and fluid stasis in the extracellular compartments to manifest as the so-called starry-sky appearance of reperfusion hepatic edema, which is characterized by visible portal venules and diminished parenchymal echogenicity that accentuate the portal venule walls. Other common gray-scale US findings include variable amounts of perihepatic hematoma, small fluid collections, and sympathetic right pleural effusion.1 In our patient population,
5 cases (13.8%) with segmental venous
congestion presented with hyperechoic segments and had increased levels of SGOT and SGPT in the first week. 12 cases (33.3%) showed raw surface collection, 15 cases (41.6%) presented with free peritoneal fluid and 18 cases (50%) had right pleural effusion.
Angeles Garcia-Criado et al,4 have performed DUS routinely in the first 3 days after OLT in all patients who have had liver transplants. In this early period it is common to detect a high RI (>0.8) that becomes normal a few days after transplantation if there are no abnormalities in the hepatic artery. Transient increased arterial resistance has been attributed to various causes, such as hepatic arterial spasm; increased portal flow, which inhibits the release of arterial vasodilators; tissue edema; increased cold ischemia time; and an older age in liver donors.5-7 They had surmised initially that this high resistance would lead to an increased risk of HAT.4 It has been reported that prompt diagnosis of HAT may be of great significance because retransplantation can be avoided by prompt revascularization.s-10
Pulsed Doppler sonography is important since blood flow can be demonstrated. Findings indicative of anastomotic stenosis are normal flow proximal to the stenosis, high-velocity
flow at the stenosis, and turbulence above
the stenosis. 11- 12 In our study, we had one patient with occluded hepatic artery in day
3, exploration was done immediately and
a thrombus was found in the hepatic artery at the anastomotic site. The thrombus was removed, anastomosis was revised and patency was regained.
Immediately after OLT, reduced portal
resistance in the presence of increased splanchnic flow leads to increased portal flow, which manifests as increased portal venous velocity at immediate post-OLT Doppler US. Another cause of increased portal venous velocity in the immediate post OLT period is transient compression of the pliable portal vein by postoperative edema or fluid. Subsequently, the body adapts, and portal blood flow decreases, with an average decrease in portal venous velocity of 20% over the next few days.1 In our study, The increased portal vein velocity was detected in
30 patients (83.3%) and was noticed to be the
most frequent abnormality seen in the early post-operative period however it declined gradually through the first month.
Portal vein thrombosis (PVT) is a
common complication of chronic liver disease with an incidence that varies between
0.6% and 15.8%.13 In past years, PVT has been taken a contraindication for LT.14 With improvement of surgical techniques and the use of aggressive approaches have made it possible to overcome PVT during LT, which is currently the only way to cure patients with end-stage liver disease and concurrent PVT1-14_ Enhancement of post-transplant care made the outcomes of PVT patients very close to those of non-PVT patients.15 In the present study, we had 7 patients with chronic portal vein thrombosis that was removed during surgery and they had high portal flow in the postoperative period declining gradually to the normal levels during the following weeks. On the other hand we had
2 patients (5.5%) with 7th day syndrome and one patient (2.7%) with small graft size who presented with abrupt decrease of the portal flow. In the latter case, the slowliness of the portal flow appeared at day 7 reaching
18 cm/s with shooting levels of SGOT and
SGPT and serum bilirubin. CT was done because Doppler US alone could not explain the laboratory abnormalities and it showed a non-enhancing wedge shaped area around a patent right hepatic vein. This area was a venous infarct that occurred despite the patency of the right hepatic vein due to the small size of the graft. The patient was lost on day 9. In these 3 patients the portal flow decreased abruptly due to marked increase of the portal flow within the graft and not due to an intraluminal cause.
Due to the limited number of patients and the relative short period of study, we agreed with Wozney et ai16 and Lerut et ai17 that thrombosis of the IVC and stenosis of the IVC anastomoses are rare vascular complications of orthotopic liver transplantation as we were not confronted with these complications. In the contrary, Yi-Ping Jia et ai15 recognize IVC thrombosis in 10 cases out of 284 LT on 5-13 days postoperatively. All were subhepatic IVC thrombosis, with 4 complete and 6 partial thromboses. Recanalization occurred in 9 cases after anticoagulation. One case with partial thrombosis got natural cure after
2 months.
Conclusion:
The early monitoring of graft hemodynamic changes by Doppler ultrasonography is of great importance as most of these changes revert to normal in the first postoperative week, however sharp decrease in arterial or portal flow indicates underlying grave vascular complications, some of them are correctable.
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