In spite of development of medical intensive care, severe acute pancreatitis (SAP) is still a fatal disease with a high mortality rate. Severe acute pancreatitis is characterized by both systemic organ failure and pancreatic and/or peripancreatic necrosis with infection. Unfortunately, pharmacological therapy including anti-inflammatory drugs, antiproteases, and probiotics could not be clarified to having beneficial effects on the course of SAP as expected (1). Prophylactic antibiotics are also controversial in acute necrotizing pancreatitis (ANP) (2). A new strategy of treatment based on pathophysiology of the disease should be mandatory.

We have clarified pancreatic ischemia with vasospasm precedes necrotic change of the pancreas in the early phase of acute necrotizing pancreatitis (3). Microcirculatory derangement due to ischemia and an increase in intravascular coagulation associated with SAP may easily cause microthrombi formation resulting occlusion of microvessels and necrosis. Therefore, a therapeutic strategy to inhibit the intravascular coagulant activity in the pancreas may be expected to prevent evolution of pancreatic ischemia into necrosis. Nafamostat mesilate is a potent serine-protease inhibitor. In addition, it acts as an anticoagulant as well as antiprotease (4, 5, 6). Regional arterial infusion technique can provide enough amount of nafamostat to the ischemic area of the pancreas. Early initiation of continuous regional arterial infusion (CRAI) of a protease inhibitor and an antibiotic in ANP has been recommended in Japanese guidelines (7). Recently, Piascik et al reported that CRAI of protease inhibitor nafamostat and antibiotic imipenem was effective in preventing complications and reducing mortality rate in SAP based on a randomized controlled trial (8).

Angiographic appearances of arterial irregularities in acute pancreatitis have already been described since 1960’s (9, 10). However, main reason for angiography was examination of the presence of complications, such as a palpable mass, suspicion of abscess or pseudocyst. Nowadays contrast-enhanced computed tomography (CE-CT) enabled us to detect pancreatic abscess, pseudocyst and pancreatic necrosis easily. In addition, pancreatic ischemia is also detected by CE-CT in the early phase of ANP. Unfortunately, relationship between angiographic abnormalities and pancreatic ischemia and/or necrosis on CE-CT findings has never been discussed in the literature.

Angiographic features in the early phase of acute necrotizing pancreatitis were investigated in a few Japanese medical centers using digital subtraction angiography with selective catheterization into the celiac artery and superior mesenteric artery (3, 11, 12). In the early phase of ANP, angiographic appearances with irregularities in various grades were observed. Angiographic abnormalities such as sudden tapering, alternative narrowing and dilatation, angulations and diffuse caliber irregularities of the intrapancreatic branch arteries are characteristic of ANP. Severe ischemic change with diffuse vasospasm and/or obstruction was observed not only in the intra- and peripancreatic arteries, but also in the extrapancreatic arteries such as the superior mesenteric artery and its branches (3). Arterial irregularities with vasospasm were already visible on the initial angiography at 12 hours after the onset. Figure 1 shows a typical appearance of vasospasm on angiography. CE-CT revealed a heterogeneous enhancement in the pancreatic head. Selective angiography via the gastroduodenal artery showed alternative narrowing and dilatation and sudden tapering of the intrapancreatic branch arteries consistent with the poorly perfused area of the pancreas on CE-CT. Improvement of ischemic change with angiographic irregularities of the intrapancreatic branch arteries were also observed on follow-up angiography (fig. 2). These findings strongly suggested that the irregular narrowing of the arteries was not caused by structural or irreversible change due to postinflammatory fibrous adhesion but was caused by vasospasm. The extent of ischemic changes with vasospasm on angiographic appearance was correlated with the extent of the poorly perfused area of the pancreas on CE-CT findings and the severity of acute pancreatitis (fig. 3, 4). Non-occlusive mesenteric ischemia (NOMI) associated with SAP was also investigated based on the angiographic appearance by Hirota et al. (13) Severe vasospastic changes of both the celiac artery and the superior mesenteric artery were observed simultaneously in patients with NOMI accompanied by ANP. Severe ischemic changes in the intraabdominal vessels may aggravate microcirculation not only in the pancreas but also in the abdominal viscera leading to pancreatic necrosis and systemic organ failure.