Angiographic identification of extrahepatic perfusion after hepatic arterial pump placement: implications for surgical prevention

Extrahepatic perfusion and incomplete hepatic perfusion after hepatic arterial infusion pump implantation: incidence and clinical implications

INTRODUCTION

This study investigates the incidence of extrahepatic perfusion and incomplete hepatic perfusion at intraoperative methylene blue testing and on postoperative nuclear imaging in patients undergoing hepatic arterial infusion pump (HAIP) chemotherapy.

METHODS

The first 150 consecutive patients who underwent pump implantation in the Netherlands were included. All patients underwent surgical pump implantation with the catheter in the gastroduodenal artery. All patients underwent intraoperative methylene blue testing and postoperative nuclear imaging (99mTc-Macroaggregated albumin SPECT/CT) to determine perfusion via the pump.

RESULTS

Patients were included between January-2018 and December-2021 across eight centers. During methylene blue testing, 29.3% had extrahepatic perfusion, all successfully managed intraoperatively. On nuclear imaging, no clinically relevant extrahepatic perfusion was detected (0%, 95%CI: 0.0-2.5%). During methylene blue testing, 2.0% had unresolved incomplete hepatic perfusion. On postoperative nuclear imaging, 8.1% had incomplete hepatic perfusion, leading to embolization in only 1.3%.

CONCLUSION

Methylene blue testing during pump placement for intra-arterial chemotherapy identified extrahepatic perfusion in 29.3% of patients, but could be resolved intraoperatively in all patients. Postoperative nuclear imaging found no clinically relevant extrahepatic perfusion and led to embolization in only 1.3% of patients. The role of routine nuclear imaging after HAIP implantation should be studied in a larger cohort.

Imaging of the hepatic arterial infusion pump: Primer for radiologists

Hepatic arterial infusion (HAI) pumps are used to deliver liver-directed therapy by allowing the administration of selective chemotherapy to the liver via a catheter implanted most commonly into the gastroduodenal artery connected to a subcutaneous pump. This selective administration helps maximize the chemotherapeutic effect within the hepatic tumors while minimizing systemic toxicity. While HAI therapy has primarily been used to treat liver-only metastatic colorectal cancer, the indications have expanded to other malignancies, including intrahepatic cholangiocarcinoma. Radiologists play an important role in pre-operative planning, assessment of treatment response, and evaluation for potential complications using various imaging studies, including computed tomography angiography, magnetic resonance imaging, and perfusion scintigraphy. This article describes the radiologist's role as part of a multi-disciplinary oncology team to help maximize the success of HAI therapy and also helps radiologists familiarize themselves with various aspects of HAI pumps.

Hepatic Artery Infusion Pumps: A Surgical Toolkit for Intraoperative Decision-Making and Management of Hepatic Artery Infusion-Specific Complications

BACKGROUND

Hepatic artery infusion (HAI) is a liver-directed therapy that delivers high-dose chemotherapy to the liver through the hepatic arterial system for colorectal liver metastases and intrahepatic cholangiocarcinoma. Utilization of HAI is rapidly expanding worldwide.

OBJECTIVE AND METHODS

This review describes the conduct of HAI pump implantation, with focus on common technical pitfalls and their associated solutions. Perioperative identification and management of common postoperative complications is also described.

RESULTS

HAI therapy is most commonly performed with the surgical implantation of a subcutaneous pump, and placement of its catheter into the hepatic arterial system for inline flow of pump chemotherapy directly to the liver. Intraoperative challenges and abnormal hepatic perfusion can arise due to aberrant anatomy, vascular disease, technical or patient factors. However, solutions to prevent or overcome technical pitfalls are present for the majority of cases. Postoperative HAI-specific complications arise in 22% to 28% of patients in the form of pump pocket (8%-18%), catheter (10%-26%), vascular (5%-10%), or biliary (2%-8%) complications. The majority of patients can be rescued from these complications with early identification and aggressive intervention to continue to deliver safe and effective HAI therapy.

CONCLUSIONS

This HAI toolkit provides the HAI team a reference to manage commonly encountered HAI-specific perioperative obstacles and complications. Overcoming these challenges is critical to ensure safe and effective pump implantation and delivery of HAI therapy, and key to successful implementation of new programs and expansion of HAI to patients who may benefit from such a highly specialized treatment strategy.

Nuclear imaging in the identification of aberrant vascular anatomy prior to hepatic arterial infusion

Hepatic arterial infusion (HAI) pumps are a specialized therapeutic modality designed to deliver high dose local chemotherapy to hepatic metastases in carefully selected patients resulting in improved survival, with patients living an average of 2 years longer than those who did not receive HAI pumps. While beneficial, these chemoinfusion pumps require a multidisciplinary approach to ensure safe and effective treatment for the patient. Here, we present a case where scintigraphic evaluation by the nuclear medicine department directly affected management of a patient with a hepatic arterial infusion pump. Variant vascular anatomy was initially discovered on the postoperative Tc-99m MAA SPECT/CT and was ultimately embolized by interventional radiology prior to initiation of chemoinfusion. This case report demonstrates the utility of obtaining nuclear medicine scintigraphy prior to chemoinfusion in patients with hepatic arterial infusion pumps.

Conventional hepatic arterial anatomy? Novel findings and insights of a multi-disciplinary hepatic arterial infusion pump program

INTRODUCTION

Variant hepatic arterial anatomy (vHAA) is thought to occur in 20-30% of patients. Hepatic arterial infusion (HAI) pump placement for liver cancers requires thorough hepatic artery dissection; we sought to compare vHAA identified during pump placement with established dogma.

METHODS

Between 2016 and 2020, n = 30 patients received a HAI pump. Intra-operatively identified vHAA was characterized and compared with published data.

RESULTS

vHAA was identified in 60% (n = 18) of patients, significantly higher than 19% (3671 of 19013) in the largest published series (P < 0.001). The most common variations were accessory left (n = 12; 40%) and replaced right (n = 6; 20%) hepatic arteries; six (20%) had ≥2 variants. Pre-operative imaging correctly identified 67% of variant hepatic arteries.

DISCUSSION

Meticulous operative dissection of the hepatic arterial tree reveals vHAA not captured by imaging or cadaveric dissection. vHAA likely has a higher prevalence than previously reported and should be addressed to optimize therapeutic efficacy of HAI pump therapy.

Hepatic artery infusion pumps

The preferential blood supply from the hepatic artery to liver tumors allows for the regional delivery of chemotherapy, commonly referred to as hepatic artery infusion chemotherapy via a subcutaneous pump. Hepatic artery infusion chemotherapy has been demonstrated to improve overall survival in select patients with colorectal liver metastasis and is a promising treatment for unresectable intrahepatic cholangiocarcinoma. This review focuses on the technical aspects of hepatic artery infusion pump placement.

Hepatic Artery Infusional Chemotherapy

Hepatic artery infusion (HAI) therapy is a well-studied and viable regional therapy for patients with hepatic metastases. Implantable pump devices may be safely placed intraarterially with minimal morbidity and HAI treatments can be used as an adjunct to systemic therapy. Future trials may address sequencing of regional and systemic therapies. However, HAI is not without complications and requires close monitoring and attention to detail but can offer reasonable control of liver tumor burden when managed jointly between medical and surgical oncologists. Herein we describe the technical aspects of HAI pump placement and review pertinent studies in primary and secondary liver tumors.

Hepatic arterial infusional chemotherapy in the management of colorectal cancer liver metastases

Colorectal liver metastases (CRLM) receive their blood supply predominantly through the hepatic artery. Intra-arterial drug delivery can optimize the dose and time exposure of chemotherapy to tumor cells while limiting systemic toxicity. Chemotherapy is most commonly administered through a catheter surgically placed in the gastroduodenal artery and connected to a subcutaneous pump. Due to its pharmacokinetics features, floxuridine is the most commonly used drug in the USA with hepatic arterial infusional (HAI) chemotherapy. To date, many clinical trials have shown the positive impact of HAI in the management of CRLM. Hence, in unresectable patients, HAI is associated with high response rates and commonly enables subsequent resection in both chemonaive and previously treated patients. Outcomes in patients converted to complete resection are similar to patients who present with initially resectable disease. In the adjuvant setting, HAI with floxuridine improves survival as well as hepatic and overall disease-free survival after complete resection of CRLM, as compared with 5-FU alone, in three of four randomized studies. To date, no trials have compared HAI combined with modern chemotherapy alone to modern chemotherapy alone in the adjuvant setting.