Contrast-enhanced ultrasound for the evaluation of hepatic artery occlusion after liver transplantation

Abstract

Introduction:Vascular complications after liver transplantation remain a major threat to the survival of recipients.HAT is a major cause of graft loss and patient mortality, with an incidence between 3% to 8% in transplant recipients.Early detection of HAT is critical because urgent revascularization is required to avoid severe graft loss. Although ultrasound is the preferred first-line imaging modality in patients with suspected HAT, the accuracy and positive predictive value of HAT on Doppler US are reported to be low. Moreover, Doppler examination of the hepatic vasculature is time consuming and requires a high level of operator skill. Conventional angiography remains the gold standard for diagnosis. Recently, contrast-enhanced ultrasound (CEUS) has begun providing real-time angiographic-like images of vessels at bed side and allowing the accurate diagnosis of arterial diseases such as hepatic artery thrombosis. The purpose of this study was to evaluate the efficacy of CEUS in detecting HAT after liver transplantation:

Materials and Methods: This is a retrospective data of the medical records of patients undergoing Liver transplantation in the Osmania General Hospital, Hyderabad between 2016 to 2018. Status of hepatic vascular assessment following liver transplantation done by conventional Doppler Ultra sonography and Contrast Enhanced Ultrasonography tests were obtained from registries of medical records.

Results:23 cases of post Liver transplantation aged between 4years and 58 years, with a median age of 30 years were included in the analysis. There were 20 males and 3 females. 14 patients underwent DDLT, 7 patients underwent LDLT, 1underwent split Liver transplantation and another 1 patient underwent Auto liver transplantation. Doppler US was inconclusive regarding patency of the hepatic artery (HA) circulation in 5 (21.7 %) of 23 transplantations. CEUS was performed in these 5 patients and detected HA thrombosis (HAT) in 2 cases and patent HA in 3 transplants. These 5 Transplants were confirmed by CT Angiography /conventional Angiography. In the subset of transplantations examined with CEUS, the sensitivity, specificity and accuracy of CEUS were 100%. CEUS was done at bedside without any Radiation and Nephro toxicity. In approximately 21.7% of cases, conventional Doppler US did not provide sufficient visualization of the HA after liver transplantation. In these cases, correct diagnosis was achieved by supplementary CEUS.

Conclusion:CEUS may be a new approach for early diagnosis of postoperative vascular complications after Liver Transplantation, and it can be performed at the bedside. It is safe will not cause any nephron toxicity and Radiation. CEUS is a fast, non-ionizing imaging modality for the initial exclusion of vascular complications after liver transplantation. CEUS shows a high specificity and PPV in the detection of vascular complications. In unclear cases CT still is considered as the gold standard