EXPERIMENTAL AND CLINICAL TRANSPLANTATION

Key words : Key words: Abdominal aortic aneurysm, Iliac artery cannulation, Organ retrieval

Liver transplant is a lifesaving treatment option for patients with end-stage liver disease.¹ The increasing number of patients on liver transplant wait lists and the scarcity of donors have led many transplant centers to accept liver grafts from donors with extended criteria.^1-4 With increased use of extended criteria donors, a higher incidence has been shown of previously undiscovered intra-abdominal pathologies, including abdominal aortic aneurysms and atherosclerotic aortic disease, which are being accidentally discovered during organ retrieval surgery.^1,4 These findings often involve technical difficulties that may hamper the success of organ retrieval and eventual transplant or even cause the loss of the organ to be transplanted.^1,5 In this case report, we present a novel case of a successful liver retrieval from a donor with brain death who was incidentally found to have an infrarenal aortic aneurysm. We also describe the management of this pathology by our organ procurement team.

A 63-year-old female patient with a past medical history of poorly controlled hypertension with 2 hypotensive drugs, diabetes mellitus, and tobacco smoking (1 pack a day) experienced a hemorrhagic stroke due to rupture of a middle cerebral artery aneurysm and died in the intensive care unit of a tertiary hospital. She was evaluated to be an organ donor, and, after confirmation of serology criteria and organ status requirements, the patient’s relatives were asked to consent to donation. During liver procurement, a previously unknown infrarenal aortic artery aneurysm was revealed (Figure 1). For our team, the infrarenal aortic artery is the preferred anatomic region for cannulation, to provide arterial perfusion of organ preservation solution to the aortic artery. The aneurysm had a thinned arterial wall, with some isolated atherosclerosis plaque. Because of the high risk of rupture of the aneurysm in the infrarenal aortic artery during aortic cannulation, the left iliac artery was chosen as the alternative route for cannulation, after dissection and ligation of the contralateral common iliac artery (Figure 2). This surgical procedure could be performed without incident, with less risk of massive hemorrhage prior to the onset of cold ischemia of the liver. The arteries of the celiac trunk and the superior mesenteric artery were carefully evaluated, and no anatomic anomalies or lesions from arteriosclerosis were found. The liver was judged to be suitable for implant after infusion of the organ preservation solution. Liver transplant was uneventful, and the recipient had no vascular complications, as shown by postoperative Doppler ultrasonography performed on day 1, day 2, and day 5. Total hospitalization duration was 9 days.

An abdominal aortic aneurysm is a large bulge in the aorta wall within the abdominal area that develops as a result of progressive weakening of the aortic wall over time.⁶ An abdominal aortic aneurysm typically develops asymptomatically and slowly over a period of years,⁶ so abdominal aortic disease in a donor often remains undiscovered until the time of organ retrieval.⁴ Donor cannulation involves the introduction of a perfusion cannula in the inferior mesenteric vein for portal perfusion and the aorta for arterial perfusion of organ preservation solution to the liver. The aortic cannula is usually inserted in the infrarenal aorta, which is also the most common site of arteriosclerotic occlusive disease.^7,8 Inadequate flushing of the liver with organ preservation solution has been associated with graft dysfunction or failure after liver transplant.⁹ When confronted by infrarenal aortic pathology during donor surgery, organ procurement teams are compelled to choose the most convenient approach to cannulate the aorta safely, in a manner most likely to avoid complications such as dissections, plaque emboli that could migrate and potentially occlude renal or hepatic arteries, disruption of organized hematomas, and poor perfusion of marginal organs, any of which could eventually lead to organ loss.^4,5,10 Various technical approaches have been proposed in these circumstances. Levi Sandri and colleagues have suggested a preference for the superior mesenteric artery for cannulation, especially if both the iliac artery and the renal artery are unusable.¹ Molmenti and colleagues have proposed cannulation just above the celiac trunk (thoracic aorta exposure is needed) or cannulation of the aortic arch.⁴ González Rodríguez and colleagues, as well as Fukuzawa and colleagues, have reported their use of anterograde perfusion by cannulation on the ascending or descending aorta.^7,10 Other teams have also reported experiences with iliac artery cannulation.^5,11 It should be noted, however, that Shimizu and colleagues also cannulated the left common carotid artery as a backup.⁵ De Carlis and colleagues have described their experience with cannulation in a donor who had a Stanford type B aortic aneurysm; they decided to cannulate the infrarenal aorta, which they judged to be sufficiently healthy to endure such a procedure.³ These examples from the literature support the notion that the presence of a pathology in a particular region of the aorta does not necessarily contraindicate procedures to be performed in other aortic sites.

As previously described in the literature, the cannulation of the thoracic aorta (ascending aorta, aortic arch, or descending aorta) is a safe and successful alternative to other preferred sites to achieve an organ procurement.² Cannulation of the ascending aorta presents several advantages, namely, the surgical exposure is brief, with minimal dissection; it is feasible in obese donors who require deep surgery; and ease of immediate clamp placement, in the event of vascular complications.^2,10 Compared with cannulation of the ascending aorta, cannulation of the aortic arch obviates the need for the extra maneuvers necessary to occlude the vessels to the head and upper extremities and allows for the use of larger cannulas.⁴ The surgeon must maintain awareness, however, that abdominal organ perfusion via a proximal approach requires immediate infusion of University of Wisconsin solution upon cannulation of the aorta.⁹

Nevertheless, the thoracic approach may not always be feasible, especially if a thoracic surgeon is not available on site during the organ procurement. Therefore, according to details presented here, iliac cannulation should be considered as a feasible alternative, especially for cases when iliac vessels are macroscopically found to be spared from the aortic pathology. It is also true that even if at least 1 of the 2 iliac arteries is healthy, it is necessary to confirm that the aortic pathology has not progressed to a critical stenosis of the infrarenal aorta, which would be a contraindication for the iliac artery approach. In point of fact and by example, Fukuzawa and colleagues have described their experience with the complication of critical stenosis of the infrarenal aorta, for which they were compelled to proceed with a thoracic cannulation.

The pathology of the aorta, especially in the infrarenal aorta, is a challenge that organ procurement teams often face unexpectedly. Proper management in such cases requires an experienced team to best ensure a successful organ retrieval and maintain good organ status for a successful transplant. We have shown that iliac artery cannulation is a safe and accessible procedure for a general surgeon who has a preferential dedication to organ procurement, especially when thoracic and cardiac surgeons are not available on site.

Volume: 22 Issue: 11 November 2024

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