Definitive treatment of cholecystitis via cystic artery pseudoaneurysm embolisation

Cystic artery pseudoaneurysm is a rare vascular complication that typically arises secondary to regional inflammation, trauma or, less commonly, idiopathic causes. It can lead to a life-threatening haemorrhage, making emergent intervention always mandated. The endovascular technique is minimally invasive but requires a good skillset and availability of expertise. This case report describes how a rare condition was successfully treated using this technique, leading to the definitive resolution of its cause: cholecystitis. There is no known published case in the literature demonstrating cystic artery embolisation resulting in the complete dissolution of the gallbladder that required no further planned cholecystectomy.

Clinical case

A 52-year-old Chinese male with no previous comorbidities presented to the emergency department of a rural hospital with a 3-day history of severe abdominal pain in the right upper quadrant. He was tachycardic and slightly hypotensive but responsive to intravenous fluid resuscitation. Tenderness was confirmed on examination without peritonism. Initial tests were consistent with anaemia (Hb 88g/L), neutrophilia (8.1x10(9)/L), and cholestasis (ALP 240 U/L, GGT 120 U/L, Bilirubin 26 mmol/L). The patient had reported no rectal blood loss or melaena. Rectal examination, however, showed possible melaena on the gloved finger.

As the patient became haemodynamically stable, prompt computed tomography (CT) of the abdomen identified a large gallbladder haematoma with a central pseudoaneurysm arising from the cystic artery and emphysematous cholecystitis (Figure 1). Antibiotics and 1 unit of red cells were administered. Discussions surrounding immediate laparotomy against endovascular intervention were held. Given continued haemodynamic stability, a helicopter was summoned to transfer the patient to the city for endovascular embolisation.

View Figure 1–4.

Access was obtained through the right femoral artery and the cystic artery pseudoaneurysm was embolised using glue and Lipiodol in a 1:2 ratio (Figure 2). Recovery was uneventful with resolving inflammatory markers and liver function tests. The patient was transferred back to the rural hospital for completion of antibiotics and recovery.

A follow-up CT, 2 months later, confirmed the complete resolution of the pseudoaneurysm and almost complete resolution of the pericholecystic inflammation (Figure 3). A subsequent ultrasound 4 months on showed no evidence of gallbladder, where it was assumed to be shrunken to a fibrotic scarred mass (Figure 4). The patient has remained asymptomatic to date since discharge from the hospital. An elective cholecystectomy was not planned.

Discussion

Cystic artery pseudoaneurysm is a rare vascular complication with few cases reported in literature.¹ Its presentation can be vague, requiring a high degree of suspicion for prompt diagnosis and management. The underlying pathophysiology is unclear, but likely to be the result of regional inflammation, trauma or idiopathic causes. Inflammation from cholecystitis can cause damage to the vessel adventitia, weakening the elastic and muscular arterial wall to form a pseudoaneurysm.² Biliary interventions such as cholecystectomy can also weaken the arterial layers, through physical manipulation, thermal injury or the presence of a nearby metallic clip.¹ Other patient comorbidities such as atherosclerosis, hypertension, diabetes or vasculitis may have a contributory role in the formation of pseudoaneurysms.³ A literature review of 67 cases found that a majority of cystic artery pseudoaneurysms were secondary to cholecystitis (61.2%), followed by cholecystectomy (26.8%).¹ Complications associated with cystic artery pseudoaneurysm include haemobilia, biliary obstruction and anaemia.¹ It can be fatal, with an estimated mortality rate of up to 50% due to severe complications of haemorrhage, hemoperitoneum and haemodynamic shock.² As such, prompt diagnosis and management are required to reduce the risk of rupture and bleeding.

The most common clinical presentation is haemobilia, which can be described through Quincke’s triad. This presents as jaundice in 60% of cases, right upper quadrant pain in 70% of cases and upper gastrointestinal bleeding in 45% of cases, with 32–40% of patients presenting with all three symptoms.^2,3

In the acute setting, a duplex doppler ultrasound can be used to diagnose a cystic artery pseudoaneurysm. This is demonstrated by an anechoic or typical yin-yang symbol (swirling flow) adjacent to the damaged artery, which can also be measured for its size and neck.^4–6 There may also be hyperechoic fluid in the gallbladder if the pseudoaneurysm has ruptured.⁴ This imaging modality is cost-effective and readily available, but the image quality can be highly dependent on the user’s skill and experience.⁶ Low sensitivity has also been reported with ultrasound, specifically with smaller lesions.² The acoustic shadow of gallbladder calculi can also obscure pseudoaneurysms in this modality.²

Alternatively, a contrast-enhanced CT can be performed, which displays a pseudoaneurysm as a well-circumscribed, high attenuation nodule.⁶ Complications such as rupture can be identified through high attenuation adjacent to the pseudoaneurysm, and intracholecystic haemorrhage can be identified through heterogeneous high attenuation in the gallbladder.^2,5 Visualisation of the aneurysm and its neck can also be seen from various angles through this method using multiplanar reconstruction.⁶ Triple-phase CT angiography has the added benefit of identifying vasculature and planning percutaneous treatment.^2,4 This method also allows for multi-organ screening and can help to determine the cause of the pseudoaneurysm.^5,6 It is also not dependent on the user, and images are quickly produced over a few minutes. However, it may not be a suitable option for patients in whom contrast usage is contraindicated.⁶

Conventional angiography is sometimes considered the gold standard, with a sensitivity of 80% and the ability to detect pseudoaneurysms less than 10mm.² This procedure can also be combined with interventional embolisation for management.^2,6 The downside is its invasive nature, which is associated with procedural risks such as haematomas, ischaemia and thrombosis.⁶

The management of cystic artery pseudoaneurysm is best done endovascularly, via embolisation or the placement of a stent, which has a high likelihood of achieving haemostasis and clearance of the aneurysm.^1,2 Its minimally invasive nature helps to enhance patient recovery. Such a technique requires experience and a good skillset. In many rural hospitals, this service is often unavailable. Embolisation agents include coils, detachable balloons, glue or gel-foam. Coils are often preferred due to their ability to target a variety of vessel sizes, and have a lower risk of increasing the pressure in the vascular lesion as compared to gel-foam and glue.⁶ This method is also preferred in high-risk surgical patients who may be haemodynamically unstable and septic, as it controls active bleeding and allows ample opportunity for resuscitation.^6,7 While gallbladder ischaemia and necrosis is commonly described in the literature as a potential risk of embolisation, its incidence is unclear. A review of 59 cases identified no patients who suffered this complication, including two patients who underwent exploration for suspected gangrenous gallbladder that found no evidence of ischaemia.⁷ If embolisation is unsuccessful, vessel ligation of the cystic artery could be indicated.¹ Following embolisation, a staged cholecystectomy is commonly arranged, alongside the removal of the pseudoaneurysm or biliary drainage.² Literature suggests, however, that embolisation alone could suffice as the sole management, particularly in older patients with higher surgical risks.⁷ However, the management of choice continues to remain controversial, with some authors suggesting that cholecystectomy should be the definitive management for cystic artery pseudoaneurysms arising from cholecystitis.^1,7 Our decision to defer surgery was supported by the patient’s clinical resolution and imaging findings, providing evidence against the notion that cholecystectomy is always necessary in such cases. It also challenges the widely held concern that embolisation of the gallbladder’s principal arterial supply would inevitably result in clinically significant ischaemic injury.

This case is unique as there are no prior reports, to our knowledge, of cystic artery embolisation resulting in the complete atrophy of the gallbladder without the need for surgical intervention. The inflammatory process from emphysematous cholecystitis is likely a contributory factor, resulting in the accumulation of fibroblasts and myofibroblasts in the tissue and eventual fibrosis.⁸ Combined with arterial embolisation, the pre-existing ischaemia was likely exacerbated, further promoting fibroblast activation and myofibroblast proliferation. This pathophysiological process, while well described in other ischaemic conditions, has not previously been reported in the context of cystic artery pseudoaneurysm embolisation.

Conclusion

Cystic artery pseudoaneurysm is a rare complication of cholecystitis. It requires a high index of suspicion, particularly in patients presenting with jaundice, shock and right upper quadrant pain. Imaging options such as ultrasound, contrast-enhanced CT and conventional angiography provide diagnostic capabilities. While there is no consensus on definitive management, endovascular embolisation has emerged as a safe and effective first-line treatment, especially in high-risk patients.