Interdisciplinary Management of Visceral Artery Aneurysms and Visceral Artery Pseudoaneurysms

A B S T R AC T The paper presents the results of treating 14 patients, namely eight patients with visceral artery aneurysms and six patients with visceral artery pseudoaneurysms. In 64.3% of the patients, the initial diagnosis was made based on the ultrasound examination. All the patients (100%) underwent CT angiography, while angiography was performed in 71.4% of the cases. Five (35.7%) patients with visceral artery pseudoaneurysms were emergently hospitalized; among them, the signs of bleeding were observed in 2 patients. In 9 patients, pathology was detected during tests for other conditions. Five (35.7%) patients underwent endovascular treatment, while 9 (64.3%) patients received surgical treatment. Endovascular interventions and open surgery demonstrated a nil mortality rate. After endovascular treatment, stent thrombosis was found in 1 patient. In the case of surgical treatment, visceral artery aneurysm was observed in 1 patient who underwent the resection of superior mesenteric artery pseudoaneurysm. Conclusions. The choice of the method of treating visceral artery aneurysms and visceral artery pseudoaneurysms depends on the location, size, anatomic features of the visceral arteries and the clinical course of the disease. Both endovascular and surgical treatment demonstrate good postoperative outcomes. Visceral ischemia is one of the most serious complications in the postoperative period, which can complicate both the diagnosis and the choice of treatment tactics.


INTRODUCTION
Visceral artery aneurysms and pseudoaneurysms are rare yet serious vascular lesions that are quite difficult to diag nose. According to literature, visceral aneurysms account for 2-3% of all the cases of vascular aneurysms (1,2). Risk factors for visceral aneurysm development include athero sclerosis, inflammatory conditions within the abdominal cavity and the retroperitoneal space, portal hypertension, connective tissue diseases, whereas visceral artery pseu doaneurysms are caused by destructive pancreatitis, iat rogenic injury to the visceral arteries, abdominal trauma (3,4). The most common visceral artery aneurysm local ization is as follows: the splenic artery -60%, the common hepatic artery -20%, the gastroduodenal artery -6%, the superior mesenteric artery -5.5%, the celiac artery -4.5%, other arteries -4%. The risk of visceral aneurysm rupture ranges from 5% for aneurysms that are 15-20 mm in diam eter to 50-70% for aneurysms with diameters greater than 30 mm (5,6). According to the international recommenda tions, endovascular or surgical treatment is indicated for the patients with visceral aneurysm larger than 20 mm, whereas, due to a high rupture risk, surgery is indicat ed for every patient with pseudoaneurysm (1,7,8). With the development of interventional radiology, endovas cular methods of treating visceral artery aneurysms and pseudoaneurysms are implemented into practice (9,10); however, traditional surgical treatment remains relevant, especially in the cases when it is impossible to perform the endovascular treatment (2,11,12). Considering a rarity of this pathology, specifics of its diagnosis and treatment, we have decided to share our own experience of treating vis ceral artery aneurysms and pseudoaneurysms.

MATERIAL
The paper presents the results of treating 14 patients during 2008-2018. Among them, there were 8 (57.1%) females and 6 (42.9%) males. The youngest patient was 47 years old; the oldest patient was 78 years old. According to the patients' past medical history, five of them underwent abdominal surgery (gastrectomy -1 patient; pancreatoduodenal re section -1 patient; pancreatic cyst drainage -2 patients; surgical revision of the abdominal cavity in multitrau ma, splenectomy -1 patient). All the patients underwent ultrasound examination of the abdominal cavity and the visceral arteries, enhanced CT angiography. Angiography of the aorta and the visceral arteries was applied in 10 cas es. By the clinical course, five patients with complaints of severe epigastric pain and general weakness were emer gently hospitalized, while nine patients complained of dull epigastric pain and epigastric heaviness.

DIAGNOSIS OF VISCERAL ARTERY ANEURYSMS AND PSEUDOANEURYSMS
In 9 (64.3%) out of 14 patients, the initial diagnosis was made based on ultrasound examination. Using angiogra phy and CT angiography, a differential diagnosis between visceral artery aneurysm and visceral artery pseudoan eurysm was made, and the size of pathological formation was determined. The localization of visceral artery aneu rysms and pseudoaneurysms is presented in Table 1.
Multiple aneurysms in the splenic artery were detect ed in 1 patient. In 1 patient, in addition to splenic artery aneurysm, infrarenal aortic artery aneurysm with a di ameter of 62 × 58 mm was found. In 1 case, celiac artery aneurysm extended to the hepatic artery (Fig. 3).
TREATMENT OF VISCERAL ARTERY ANEURYSMS AND PSEUDOANEURYSMS Five (35.7%) patients received endovascular treatment. Endovascular treatment tactics were determined by both vascular surgeon and interventional radiologist. Emboli zation was used in 2 patients with pseudoaneurysm of the distal part of the splenic artery.
One patient with an aneurysm of the proximal part of the splenic artery underwent coil occlusion. Endovascular aneurysm repair was performed in 1 patient with celiac artery pseudoaneurysm and one patient with common hepatic artery aneurysm.
In other cases (64.3%), surgical treatment was pre ferred: ligature of the splenic artery -1 patient; resec tion of splenic artery aneurysm with direct endto end anastomosis -2 patients; resection of celiac artery aneurysm and celiac artery reconstruction with a polytet rafluoroethylene (PTFE) graft -1 patient (Fig. 4); resec tion of pancreaticoduodenal artery aneurysm and direct suture of the pancreaticoduodenal artery -1 patient; re section of left gastric artery aneurysm with left gastric artery plasty -1 patient; resection of superior mesenteric artery aneurysm with vein plasty -1 patient; resection of superior mesenteric artery pseudoaneurysm with direct sutures -2 patients.
Endovascular interventions and open surgery demon strated a nil mortality rate. After endovascular treatment, stent thrombosis was found in 1 patient. After surgical treatment in the early postoperative period, serious com plication (visceral artery aneurysm) was observed in 1 pa tient who underwent the resection of superior mesenteric artery pseudoaneurysm.
Considering a particular interest of this case report, we propose its more detailed presentation.
A 57yearold female patient with complaints of gener al weakness, mild epigastric pain, and diarrhea were hos pitalized to the Department of Surgery No 1. According to past medical history, the patient had undergone pancre aticoduodenal resection for pancreatic head tumor three weeks prior hospitalization. According to the surgical treatment protocol, pancreatic tumor infiltrated the ad ventitia of the anterior surface of the superior mesenteric artery that required the preparation of malignant pancre atic formation at the subadventitial layer of the superior mesenteric artery. The pancreatic tumor was removed ad block without any signs of intraoperative bleeding.
At the hospitalization stage, abdominal ultrasound was performed that revealed the collection of hypoechoic fluid 5 × 2.5 × 1.5 cm in size in the epigastric region. To specify the diagnosis, there was prescribed CT angiography of the abdominal cavity, that, during the arterial phase of con trast administration, revealed a rounded area of contrast medium accumulation 50 × 42 mm in size to the left of the aorta and approximately 1.5-2 cm below the origin of the superior mesenteric artery.
The interventional radiologist did not recommend en dovascular treatment of pseudoaneurysm as, according to CT angiography, significant anatomical and topographical changes in the superior mesenteric artery were observed.
Taking into account the presence of superior mesenter ic artery pseudoaneurysm confirmed by CT angiography, the vascular surgeon recommended surgical resection of superior mesenteric artery pseudoaneurysm. The patient underwent elected laparotomy. During surgical revision, Fig. 4 Arterial reconstruction of the celiac artery with a PTFE Graft. in the projection of the superior mesenteric artery, a pul sating mass 5 × 4 cm in diameter was detected. The superi or mesenteric artery was prepared proximally and distal ly to the pseudoaneurysm. After injection of 5,000 units of heparin and clamping (compression) of the superior mesenteric artery, pseudoaneurysm was mobilized on the anterior surface of the superior mesenteric artery, where a 2-3mm opening was found. Considering a pronounced subacute process, we have decided to perform minimally invasive surgery. Namely three single transverse sutures were applied to the superior mesenteric artery. After blood flow restoration, excellent pulsation of the superior mes enteric artery distal to sutures was detected.
However, the patient's clinical condition in the post operative period was complicated; diffuse abdominal pain and weakly positive signs of peritoneal irritation were ob served on the second day after surgery. CT angiography of the abdomen was emergently performed that revealed superior mesenteric artery occlusion. Relaparotomy and surgical revision were urgently performed, taking into account acute intestinal ischemia. Superior mesenteric artery occlusion at the site of pseudoaneurysm resection was found. Arterial reconstruction has been decided to be performed: iliacmesenteric bypass with the great saphe nous vein (Fig. 6).
As it was impossible to assess the viability of the small intestine, the abdomen was left open for eight hours for planned secondlook reoperation; then, the small intes tine was surgically revised. There was found the necrotic segment of the jejunum. There was performed segmental resection of the jejunum (70-80 cm). The postoperative course was uncomplicated. There were prescribed antiin flammatory, detoxification, and antiplatelet therapies.

DISCUSSION
With the implementation of diagnostic methods such as angiography and CT angiography into clinical practice, visceral artery aneurysms and pseudoaneurysms can be detected before their complications develop that, certain ly, increases the quality of treatment thereby reducing the risk of postoperative complications (8,13).
Digital angiography is currently the gold standard for diagnosing pseudoaneurysms as it allows realtime assess ment of the site of extravasation. Digital angiography has the highest sensitivity (100%), followed by CT (67%) and ultrasound (50%) (14). In our study, the initial diagnosis of visceral artery aneurysm based on ultrasound exam ination was made in 64.3% of the patients; all the patients (100%) underwent CT angiography, while angiography was performed in 71.4% of the cases.
The ratio of visceral artery aneurysms to visceral ar tery pseudoaneurysms depends on visceral artery loca tion. The most common visceral artery aneurysm localiza tion is the splenic artery while pseudoaneurysms of the gastroduodenal and superior mesenteric arteries are more common as compared to their aneurysms (89% vs. 11% and 67% vs. 33% respectively) (2,9).
More than 60% of visceral artery pseudoaneurysms occur secondary to pancreatitis, and almost 10-17% of pseudocysts in patients with chronic pancreatitis are com plicated by the development of visceral artery pseudoan eurysms (15).
Blunt or penetrating abdominal trauma and iatrogenic injury after hepatobiliary or vascular surgery, or pancre atic head biopsy may result in visceral artery pseudoaneu rysm as well (7,13).
Approximately 80% of visceral artery aneurysms are asymptomatic being detected during tests for other con ditions. Almost 20% of visceral artery aneurysms have severe clinical manifestations; in 9% of the cases, they result in death (2). Clinical manifestations of visceral ar tery aneurysms are nonspecific. The patients complain of abdominal discomfort and abdominal pain that is not related to food intake. At the same time, in most patients with visceral artery pseudoaneurysms, the symptomatic clinical course is found; they complain of abdominal and epigastric pain; hematemesis and melena may be observed (3). Among 14 patients, 5 (35.7%) individuals with visceral artery pseudoaneurysms were emergently hospitalized; among them, the signs of bleeding were observed in 2 pa tients. In 9 patients, pathology was detected during tests for other conditions; among them, three patients with re current symptoms of chronic pancreatitis were hospital ized in the surgical department.
The choice of the method for treatment of visceral artery aneurysms and pseudoaneurysms remains controversial, and the prognostic indicators of the clinical course depend on many factors, namely aneurysm localization and size, clinical manifestations, work experience of the surgical team and technical capabilities of a healthcare institution (7).
The method of choice should be endovascular treat ment (selective embolization, coils, stent, gelatin foam, Fig. 5. CT scan of superior mesenteric artery pseudoaneurysm Fig. 6 Iliac-mesenteric bypass with the great saphenous vein polyvinyl alcohol), which is performed under local anes thesia (9,10). According to literature, endovascular treat ment of visceral artery aneurysms was effective in 95-98% of cases. Reintervention was required in 3-5% of cases. Aneurysmrelated thirtyday mortality rate was 3-4%, and the periprocedural mortality rate was about 6% (3,9). In our study, only 5 (35.7%) patients underwent en dovascular treatment. Two (14.3%) patients underwent attempted endovascular treatment that was not effective due to tortuosity of the affected visceral artery.
Contraindications to endovascular treatment may in clude vascular tortuosity and the length of the affected artery, especially in case of stent implantation when there is a need to fix the proximal and distal ends (8). Compli cations of endovascular surgery may include thrombosis resulting in visceral ischemia, stent or coil migration, stent occlusion, reperfusion, rebleeding, nephropathy, accessrelated complications (femoral pseudoaneurysm, hematoma, thrombosis or embolism, infection) (13).
When it is impossible to perform endovascular treat ment, surgical treatment, that involves the exclusion of aneurysmal sac, arterial bypass, vessel ligature, is recom mended. Among 14 patients, surgical treatment was per formed in 64.3% of the cases. In some cases, organ resec tion (splenectomy, colon resection) is needed (11,16). Due to the constant collateral circulation between the visceral arteries, most visceral artery aneurysms can be treated by ligation or embolization. However, they cannot be applied in superior mesenteric artery aneurysms when endovas cular or surgical revascularization is always mandatory (4).
The choice of treatment tactics (surgical or endovascu lar) for hemodynamically unstable patients is controver sial. We prefer surgical treatment, although there were a few articles on successful endovascular treatment of visceral artery aneurysms in hemodynamically unstable patients (10,17).
Both in the case of endovascular surgery and tradition al surgery, the most serious postoperative complication is visceral ischemia that not always is acute, thereby compli cating both timely diagnosis and adequate treatment (18).
In the study group, visceral ischemia as a postoperative complication after surgical treatment of superior mesen teric artery pseudoaneurysm was observed in 1 patient.
The clinical picture was changed by a specific sign of the postoperative course (changes in the trajectory of the gastrointestinal contents passage after pancreaticoduodenal resection, adhesions, the significant extent of surgery). This case confirmed that in case of severe postoperative course, even if surgery was uneventful, the presence of iatrogenic injury to the visceral arteries should be taken into account. Ul trasonography was found to play an important role in the postoperative period. If there is any fluid collection, a differential diagnosis with the detection or exclusion of an active venous or arterial blood flow is required. If there are any abnormal abdominal masses, an objective diagnostic method is CT with intravenous bolus contrast medium injection.
The choice of surgery extent (resection of superior mesenteric artery pseudoaneurysm and application of direct transverse single sutures) was substantiated by the fact that, intraoperatively, the superior mesenteric artery was sufficiently wide that allowed us to apply su tures without stenosis formation. Moreover, our goal was to minimize the extent of surgery, as, in the case of a sub acute process, anastomosis or plasty may result in the de velopment of other postoperative complications.
Superior mesenteric artery occlusion was diagnosed on the second day after surgery, however. This was most likely due to pronounced infiltrative changes in the pancreaticoduodenal region. An unfavorable prognostic criterion in the postoperative period is intestinal ischemia. Therefore, rapid recognition of the patient's clinical condition is the key to treatment success (19). If the di agnosis of mesenteric ischemia is confirmed, emergency surgery is needed (20).
We performed emergency surgery and arterial reconstruction, namely iliacmesenteric bypass. Next day, segmental resection of the jejunum (70-80 cm) was performed. As it is impossible to assess the viability of the small intestine, many surgeons use minimally in vasive surgical interventions (resection of the necrotic segment) and delayed, secondlook surgical revision of the intestine (21). On the other hand, practically no alternative approach to surgical treatment of the patients with mesenteric ischemia exists (22). The factor of acute intestinal ischemia duration is of extreme importance in the prediction of surgical treatment success for the patients with mesenteric ischemia (23). Therefore, careful attention should be paid to clinical signs of acute intestinal ischemia, especially in the patients who underwent visceral artery reconstruction.

CONCLUSIONS
The choice of the method for treatment of visceral artery aneurysms and visceral artery pseudoaneurysms depends on the location, size, anatomic features of the visceral ar teries and the clinical course of the disease. Both endovas cular and surgical treatment demonstrate good postoper ative outcomes.
In the case of visceral artery reconstructions, the potential risk of both the development of acute mes enteric ischemia and visceral artery occlusion should be taken into account. Visceral ischemia is one of the most serious complications in the postoperative period, which can complicate both the diagnosis and the choice of treatment tactics. In acute intestinal ischemia, emergency surgery, that involves the revascularization of the intestine, the assessment of intestinal viability and segmental resection of the necrotic intestinal segment, is required.