Acute pancreatitis complications: collections, bleeding and beyond. Poster No.:

C-1450

Congress:

ECR 2012

Type:

Educational Exhibit

Authors:

E. Rivera , M. Santillana , M. Villa , I. Artero-Munoz , J. M.

1

2

1

2

1

3 1

Rodriguez Mesa , J. J. MUÑOZ RUIZ-CANELA ; Malaga/ES, 2

3

Málaga/ES, MALAGA/ES

Keywords:

Abdomen, Pancreas, Interventional non-vascular, CT, CTAngiography, Fluoroscopy, Embolisation, Drainage, Abscess, Hemorrhage

DOI:

10.1594/ecr2012/C-1450

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Learning objectives •

To present the highlights of pancreatic anatomy, with emphasis on the vascular system.

•

To analyze the imaging strategies for vascular and non-vascular complications of acute pancreatitis.

•

To explain the interventional management (vascular or non vascular) of those complications.

Background Acute pancreatitis is a serious condition with a high prevalence of complications. With the development of cross-sectional imaging and advanced interventional techniques, percutaneous drainage has become the first line of treatment for collections, pseudocysts and abscesses.

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Fig. 1 References: cancer research institute Peripancreatic circle: Pancreatic head irrigation: • •

Superior pancreatoduodenal artery originated from hepatic artery. Inferior pancreatoduodenal artery originated from superior mesenteric artery.

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Fig. 2 References: Wikimedia commons. Gray's anatomy. Gastroduodenal artery originated from splenic artery. Both arteries run in the groove between the pancreas and the duodenum and supply the head of the pancreas. The pancreatic branches of splenic artery also supply the neck, body and tail of the pancreas. The largest of those branches is called the pancreatic magna artery; its occlusion, although rare, is fatal. Page 4 of 17

The body and neck of the pancreas drain into splein vein; the head drains into the superior mesenteric and portal vein.

Imaging findings OR Procedure details Non-vascular complications: •

Acute pancreatic fluid collections:

Acute fluid collection occurs in the vicinity of the pancreas. Early in the course of severe acute pancreatitis. Do not have perceptible wall. Often conform to the anatomic spaces. Spontaneous resolution in 50% of patients. It progresses to pseudocysts and abscesses in the other 50% of patients. Drainage is only necessary if it becomes infected. •

Pseudocysts:

Definition: A sterile organized peripancreatic fluid collection that persists for more than 4 weeks after the beginning of acute pancreatitis. Collection of pancreatic juice usually sterile enclosed by a well-defined wall or fibrous or granulation tissue. It occurs in 10-20% of acute pancreatitis patients. Usually in the retroperitoneal space. Approximately half of pseudocyst resolves spontaneously and 25% tends to secondary infection.

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Fig. 3: Grade E acute pancreatitis with pleural extension of an abdominal pseudocyst. References: E. Rivera; SERVICIO ANDALUZ DE SALUD (SAS), Malaga, SPAIN Treat when: • • • • • •

Persistent enlargement (larger than 5cm that have been present for longer than 6 weeks) Severe pain. Infection. Hemorrhage Biliary obstruction. Gastrointestinal obstruction.

With the advent of cross-sectional imaging, percutaneous drainage has become the preferred treatment for many pancreatic pseudocyst. (Lower than 5% recurrence rate at 1 year).

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Fig. 4: (a) Enhanced CT on portal phase shows necrosis of pancreatic body and tail (arrow). Besides it is observed an abdominal collection in front of the pancreas with thick walls diagnosed as pseudocyst. (b) It was punctured with a 18 G needle and a drainage catheter (8,5 F) was inserted. Good radiological evolution was observed in the next control CT. References: E. Rivera; SERVICIO ANDALUZ DE SALUD (SAS), Malaga, SPAIN •

Pancreatic necrosis (PN):

Pancreatic necrosis is considered to be one of the most important complications and the most important indicator of disease severity. Pancreatitis is defined as necrotising when it has more than 30% of the gland. Diffuse or focal areas of nonviable pancreatic tissue. 10-15% of all cases of acute pancreatitis. It usually appears between 48 and 96 hours after symptoms onset; thus, early CT within 12 hours of symptoms onset be falsely reassuring.

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PN can be associated with disconnection of the main pancreatic duct (high risk of infection). Mortality: • •

Infected pancreatic necrosis: 15-50%. Sterile pancreatic necrosis: 10%

Cause: Thrombosis of the pancreatic microcirculation. Diagnosis: Lack of parenchymal enhancement following i.v. contrast administration. Less than 30UH correlates well with necrosis. Normal parenchyma: 80-150UH. Infection is a mayor complication of pancreatic necrosis (30-70% cases). It's responsible for approximately 80% of deaths in patient with severe acute pancreatitis. Sterile necrosis: Do not treat. Initially: medical treatment.

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Fig. 5: (a) Fatty liver and focal necrosis in the pancreatic tail with an homogeneous collection in the pancreatic bed. (b)Another patient with focal necrosis in the pancreatic neck. Less than 30 UH were detected in the circles areas. References: E. Rivera; SERVICIO ANDALUZ DE SALUD (SAS), Malaga, SPAIN •

Pancreatic abscess:

Well-circumscribed intra-abdominal collections of pus which usually lie in close proximity to the pancreas. It contains pus and little or no necrotic debris. It occurs late in the course of acute pancreatitis. Mortality 70-80%. Typically 4-6 weeks after symptoms onset. Diagnosis: Focal areas of low attenuation in the vicinity of the pancreas surrounded by a thick wall that may be enhanced.

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The presence of bubbles of gas within a collection is strongly suggestive of abscess (20% of abscesses contains gas). Percutaneous drainage has been found successful in 50-80% of patients.

Fig. 6: Peripancreatic abscess: (a) Enhanced CT on portal phase shows necrotizing acute pancreatitis in the pancreas tail (arrow) surrounded by a collection with enhanced walls. (b) That peripancreatic abscess was punctured with a 18G needle and a multipurpose drain catheter was inserted (c). (d)Two months after, in a enhanced CT on portal shows a small residual abscess in the anterior pararenal space (arrow). References: E. Rivera; SERVICIO ANDALUZ DE SALUD (SAS), Malaga, SPAIN Requirements for drainage: • • •

50.000 platelets / µL or higher. INR of 1,5 or less. In coagulation deficiencies: Attempt to normalize the coagulation status before the procedure (transfusion of platelets, fresh frozen plasma and vitamin K administration).

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Catheters must be placed for gravity drainage and routinely irrigated with saline solution every 8 hours. When remove the catheter? 1. 2.

No residual collection on follow-up CT. When the drain output isn't purulent and less than 10 ml on two consecutive days.

Collapsed collection on CT + persistent drain output = Consider duct connection. Percutaneous necrosectomy: It consists of the utilization of percutaneously sited drains like an access port for minimally invasive surgical debridement of infected pancreatic necrosis. This procedure requires a catheter to be inserted within the infected cavity (usually a 8,5F pigtail catheter). The track of this catheter is then dilated to allow insertion of 30F sheath in order to pass an operating nephroscope. Solid material is removed from cavity piecemeal via the nephroscope which also allows intermittent irrigation and suction of the cavity. Surgery can be reserved for those patients who are hemodynamically unstable and require rapid, large volume debridement that can only be performed via an open surgical incision.

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Fig. 7: Percutaneous necrosectomy: (a) Severe acute necrotizing pancreatitis of the body and pancreatic tail with unorganized peripancreatic collections. The patient didn't improve clinically and was suspected to have superinfection of pancreatic necrosis. It was settled a 8,5F pigtail catheter. The track of this catheter was dilated to allow insertion of 30F sheath to pass an operating nephroscope (c). Enhanced CT on portal phase shows radiological improvement with nearly resolution of the mentioned collections. References: E. Rivera; SERVICIO ANDALUZ DE SALUD (SAS), Malaga, SPAIN Vascular complications (25% of patients with acute pancreatitis) 1. Venous thrombosis: Commonest vascular complication. Cause: *Secondary to inflammatory intimal injury. *External compression by fluid collections. Page 12 of 17

Location: Splenic (10-40%), superior mesenteric and portal vein. May be associated with hepatic infarction and portosystemic collaterals.

Fig. 8: Venous thrombosis: (a and b) Patient with acute pancreatitis showing filling defect in superior mesenteric and portal vein (arrows). (c) D grade acute pancreatitis with filling defect in the splenic vein.(d) Enhanced CT on portal phase shows huge filling defect inside the portal vein with formation of gastric varices (arrow). References: E. Rivera; SERVICIO ANDALUZ DE SALUD (SAS), Malaga, SPAIN 2. GI bleeding: Hemorrhage is one of the most life threatening complications of pancreatitis. Massive hemorrhage is rare but frequently lethal complication. Causes: •

Erosion of vascular structures is caused by the proteolytic activity of pancreatic enzymes, which are released during subacute or recurrent chronic pancreatitis or after severe trauma. Page 13 of 17

• • •

Formation of pseuaneurysms. Enlargement of pseudocysts and rupture into GI estructures or intrapseudocyst hemorrhage. Occasionally, the pseudocyst erodes the large vessels such as the aorta and portal vein. Splenic artery > gastroduodenal > pancreatoduodenal arteries > peripancreatic vessels.

High mortality rate. Angiography is the procedure of choice for identification of the site and source of bleeding. The source and site of bleeding are usually diagnosed by identification of the erosive arterial changes or pseudoaneurysm formation. Surgery should be reserved for actively bleeding, hemodynamically unstable patients; for failed embolization; and for other secondary complications such as infection or extrinsic compression.

Fig. 9: Patient with severe acute pancreatitis. A, b and c: enhanced CT on arterial phase. (a) High density image surrounding the liver diagnosed as hemoperitoneum. (b) It is observed high attenuation of the fat around the pancreatic bed and an enhanced artery probably responsible of bleeding (c). Huge intraperitoneal bleeding around the

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greater curvature of the stomach. (d) Conventional angiography image shows constrast extravasation in the gastroduodenal artery. It was twice embolized with coils in the proximal and distal segment of the gastroduodenal artery to control the hemorrhage (e and f).Unfortunately the patient died a day later. References: E. Rivera; SERVICIO ANDALUZ DE SALUD (SAS), Malaga, SPAIN

Fig. 10: Intrapseudocyst bleeding: (a and b): Enhanced CT on portal phase shows cholelitiasis and a collection with enhanced walls with high attenuation image within, sugestive of intrapseudocyst bleeding. (c and d) : conventional angiography image shows celiac and superior mesenteric artery without any extravasation of contrast. Hemorrhage was spontaneously autolimited. References: E. Rivera; SERVICIO ANDALUZ DE SALUD (SAS), Malaga, SPAIN 3. Pseudoaneurysms (PSA): Common vascular abnormality that represents disruption in arterial wall continuity with patent flow in a defined space beyond the confines of the vessels. 3,5-10% of patients with acute pancreatitis.

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Cause: digestive effects of pancreatic enzymes on local arteries causing weakness of the artery wall. Localization: splenic (40%), gastroduodenal (30%), pancreaticoduodenal (20%), gastric (5%) and hepatic artery (2%). PSA --> enlarge --> rupture --> hemorrhage. Diagnosis: Arterial phase CT allows delineation of PSA anatomy and identification of active bleeding, providing a road map for subsequent intervention.

Fig. 11: Pseudoaneurysm (PSA): (a) Conventional angiography image shows PSA of splenic artery. (b) PSA was treated by splenic artery embolization with platinum coils. (c) Postembolization angiogram shows absence of enhancement within the PSA and no complications were observed after the procedure. References: E. Rivera; SERVICIO ANDALUZ DE SALUD (SAS), Malaga, SPAIN Management:

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Symptomatic PSA should be treated. The location of the PSA may affect its outcome. However, if left untreated, rupture of extra-organic visceral PSA is correlated with a mortality rate that may approach 100%. Value: size of the PSA neck and collateral supply.

Conclusion

The complications of pancreatitis are many and potentially severe, in particular vascular complications. Interventional vascular radiology plays an increasing role in both the diagnosis and the treatment of these complications.

Personal Information References 1. 2. 3. 4.

5. 6. 7. 8. 9.

Pancreatic arterial anatomy: depiction with dual-pase helical CT. Radiology 1998; 208: 537-542. Imaging of the complications of acute pancreatitis. AJR 2011; 197: W375-381. Diagnosis and management of pseudoaneurysms: An update. Curr Probl Diagn Radiol 2099;38:170-188. CT-Guided percutaneous catheter drainage of acute necrotizing pancreatitis: Clinical experience and observations in patients with sterile and infected necrosis.AJR 2009,192:110-116. Interventional radiological treatment in complications of pancreatitis. European Journal of Radiology 43 (2001) 219-228. Imaging and intervention in acute pancreatitis. Radiology 1994; 297-306. Acute pancreatitis: The role of imaging in diagnosis and management. Clinical Radiology 66 (2011) 164-175. Body TC and correlation MR. Lee. Learning vascular and interventional radiology. J.J. Muñoz, R. Ribes

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