Non-occlusive hepatic artery hypoperfusion syndrome and imaging findings: a systematic review

A systematic review of diagnostic and interventional techniques in non-occlusive hepatic artery hypoperfusion syndrome

OBJECTIVE

This systematic review aims to elucidate the diagnostic capabilities of imaging techniques in identifying Non-Occlusive Hepatic Artery Hypoperfusion Syndrome (NOHAH) and to evaluate the efficacy and outcomes of splenic artery embolization (SAE), including the choice and placement of embolic agents.

MATERIALS AND METHODS

A comprehensive literature search was conducted using PubMed, CINAHL, and Scopus databases, adhering to PRISMA guidelines. Fifteen studies encompassing 240 patients treated with embolization (using coils or Amplatzer Vascular Plugs (AVP)) were analyzed. Key metrics assessed included patient demographics, embolization techniques, embolic agents, technical success, radiologic findings pre- and post-embolization, and complication rates.

RESULTS

Among the 240 patients studied, 177 (73.8%) were reported by gender, with a majority being male (127/177, 71.7%). Doppler ultrasonography (DUS) emerged as the primary initial screening tool in 80% of studies. The hepatic arterial resistive index (RI) was a critical parameter, with mean values significantly decreasing from 0.84 pre-embolization to 0.70 post-embolization (p < 0.001). All cases confirmed technical success via digital subtraction angiography, revealing delayed hepatic arterial filling without stenosis or thrombosis. Coils were the predominant embolic agent, used in 80.8% of patients, followed by AVP in 16.3%. The overall mortality rate was 4.58%, with 29 major and 3 minor complications noted. Notably, proximal placement of coils in the splenic artery was associated with lower mortality rates compared to distal placement and showed comparable complication rates to AVPs.

CONCLUSION

DUS is a reliable screening modality for NOHAH, with post-SAE assessments showing significant improvements. The choice and location of embolization significantly impact patient outcomes, with proximal placement of coils emerging as a preferable strategy due to lower mortality rates and comparable complication profiles to alternative methods.

Diagnostic Value of Color Doppler Ultrasound and Contrast-Enhanced Ultrasound in the Artery Steal Syndrome After Orthotopic Liver Transplantation

Purpose

This study aimed to investigate the application of color Doppler ultrasound (CDU) and contrast-enhanced ultrasound (CEU) in the early diagnosis of arterial steal syndrome (ASS) after orthotopic liver transplantation (OLT).

Patients and Methods

A total of 1827 patients received OLT in our department between January 2007 and December 2021, and CDU and CEU were performed after surgery. Ultrasonographic data were collected and further analyzed. ASS was confirmed by digital subtraction angiography (DSA), and the use of splenic artery embolization was dependent on the DSA findings and clinical conditions. The ultrasonographic data were collected before and after embolization.

Results

ASS was found in 23 patients (23/1827; 1.26%). CDU: the portal vein velocity was higher than normal in 17 patients (52.83±21.74 cm/s); the hepatic artery flow signals disappeared in 7 patients; the hepatic artery velocity was 13.57±5.85 cm/s in 16 patients. In 23 patients, the spleen artery velocity was 170.12±32.04 cm/s. CEU: the hepatic artery was observed in 7 patients without hepatic artery flow signals on CDU; in 23 patients, the contrast agent reached the portal vein at the presence of contrast in the hepatic artery or earlier (difference: 2.21±1.09 s). Splenic artery embolization was done in 17 of 23 patients with ASS. The hepatic artery flow velocity, hepatic artery resistance index, splenic artery velocity and time to the presence of contrast were significantly improved after embolization (P<0.05).

Conclusion

CDU and CEU are the preferred, effective tools in the diagnosis of ASS. Reduced peak hepatic artery velocity, increased spleen artery velocity and reduced time difference in the contrast reaching the portal vein and hepatic artery are indicative of ASS.

Multimodality Imaging after Liver Transplant: Top 10 Important Complications

Patients who have undergone liver transplant are now regularly seen in day-to-day radiology practice. All surgical techniques for liver transplant require arterial, portal venous, hepatic venous and caval, and biliary anastomoses. This review is focused on the 10 "not to be missed" complications of liver transplant that affect the health and life of the graft and graft recipient. Arterial complications are the most common and devastating. Early hepatic artery thrombosis may be catastrophic because the biliary tree is solely dependent on the hepatic artery after transplant and collateral vessels have not yet formed. In contrast, delayed hepatic artery thrombosis may be more insidious as collateral arteries develop. US findings of delayed hepatic artery thrombosis may be similar to those of hepatic artery stenosis and celiac artery stenosis. Splenic artery steal syndrome is an increasingly recognized cause of graft ischemia. Venous complications are much less common. Hepatic venous and caval complications are notable for their increased incidence in living-donor and pediatric transplants. Biliary complications often result from arterial ischemia. Biliary cast syndrome is a notable example in which ischemic biliary mucosa sloughs into and obstructs the duct lumens. Neoplasms also may occur within the hepatic graft and may be due to recurrent malignancy, posttransplant lymphoproliferative disorder, or metastases. US is the initial imaging modality of choice, particularly in the acute postoperative setting. Further evaluation with contrast-enhanced US, CT, or MRI; catheter angiography; endoscopic retrograde cholangiopancreatography; and/or nuclear medicine studies is performed as needed. An invited commentary by Bhargava is available online. Online supplemental material is available for this article. ^©RSNA, 2022.