ARRS 2022 Abstracts

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2102. High-Yield Doppler Ultrasound Features for Diagnosing Hepatic Artery Complications in Transplanted Livers: A Single-Institution Experience
Authors * Denotes Presenting Author
  1. Rana Rabei; University of California - San Francisco
  2. Shareef Syed; University of California - San Francisco
  3. John Roberts; University of California - San Francisco
  4. Vickie Feldstein; University of California - San Francisco
  5. Sean Woolen; University of California - San Francisco
  6. Nicholas Fidelman; University of California - San Francisco
  7. Hailey Choi *; University of California - San Francisco
Objective:
This study aims to identify Doppler ultrasound (US) features most predictive of hepatic artery complications in liver transplant recipients.

Materials and Methods:
A single-center radiology report database was retrospectively queried from 2015-2021. Inclusion criteria were liver transplant recipients with Doppler US followed by either CT angiogram (CTA) or digital subtraction angiogram (DSA) in 30 days. If multiple US exams were completed within 30 days, the exam closest to the CTA or DSA was included. Doppler US images were analyzed for Doppler waveforms of the main and intrahepatic arteries (MHA, IHA) by a single reader with 4 years of US experience. Chart review was performed for patient age, sex, transplant type (whole vs. single lobe), time from transplant to US, and time from US to angiogram. Image features included: waveform morphology (normal, mild tardus parvus waveform (TPW: either acceleration time (AT) or resistive index (RI abnormal), TPW (AT > 0.08s and RI < 0.5), no flow, and high resistance (RI >0.8)). Study outcome of hepatic artery complication included hepatic artery stenosis (HAS), hepatic artery thrombosis (HAT), and dissection, based on angiographic findings.

Results:
Final study population was 142 exams in 108 patients: 70 cases were confirmed on CTA, 59 with DSA, and 13 with both. Mean time interval between US and angiogram was 6.3 days (range 0-28 days). Hepatic artery complications included stenosis (43/142 30.3%), thrombosis (24/142, 16.9%), and dissection (10/142, 7%). Other abnormalities were vasospasm, vasculitis, pseudoaneurysm, and splenic steal (11/142, 7.7%). On univariate analysis, transplant type (whole liver more commonly associated with complication (81.8% vs. 64.6%, p=0.03), as well as waveforms, RI and AT for both IHA and MHA were significant. For MHA, RI was lower (mean 0.57 vs. 0.66, p=0.006), AT higher (0.77 vs. 0.46, p=0.002), and TPW more common (29.9% vs. 13.8%, p<0.001) for cases with complications. For IHA, RI was also lower (0.43 vs. 0.59, p<0.001), AT was higher (mean 0.62, and median 0.12 vs. mean 0.05 and median 0.04, p<0.001), and TPW was more common (51.9% vs. 15.4%, p<0.001) for those with complications. On multivariate analysis, IHA waveform and AT were significant predictors (p<0.001 for both). Either absent flow or TPW in the IHA resulted in 75% sensitivity and 81% specificity for complications. Adding mild TPW to this resulted in a greater sensitivity of 94%, but lower specificity of 68%. On ROC analysis, IHA AT had an AUC of 82.5% with an optimal threshold of 0.075 seconds (82% specificity, 78% sensitivity). IHA RI had an AUC of 74.7% with an optimal cut-off of 0.50 (70% specificity, 81% sensitivity).

Conclusion:
For predicting hepatic artery complications, IHA waveforms and AT are the most important US features. IHA waveform abnormalities of no flow, TPW, and mild TPW can be used as a screening tool for hepatic artery complications; these patients may benefit from further evaluation with angiography or close follow-up. ROC analysis supports the accepted AT cut-off of 0.08 seconds for detecting hepatic artery complications.