Aneurysms of the middle colic arterial branches are extremely rare, the main manifestation occurs due to the rupture and intraabdominal bleeding making death possible in up to 70% of cases. Herein, we report a case of a male patient, who is 50 years old and who displays intermittent, recurrent, and self-limited episodes of a digestive hemorrhage that has been symptomatic during the course of a three-month investigation. After an extensive investigation, the patient was submitted to angiography detecting a pseudoaneurysm in the middle colic branch, being treated with embolization by micro-coils. Intermittent digestive hemorrhages from an obscure source can represent a diagnostic challenge, due to the high degree of clinical suspicion for performing the correct differential diagnosis. Arteriography must not be delayed whenever a pseudoaneurysm with active bleeding is suspected, as this exam is selected for diagnosis and the preferred method for conclusive treatment.
Keywords: Arterial branches; Angiography; Pseudoaneurysm; Laparoscopic surgery; Hypertension
Aneurysms are defined whenever the width of an artery is dilated more than 1.5 times its normal size and then they can be classified as true aneurysms and false aneurysms (pseudoaneurysms). Visceral Artery Aneurysms (VAAs) are rare with an estimated incidence ranging from 0.01% to 2% in autopsies and angiographic series . Aneurysms can affect any of the abdominal aorta branches, although hepatic and splenic aneurysms represent 80% of the reported cases. Aneurysms of the superior mesenteric branches are extremely rare especially in the middle colic [2,3].
The majority of VAAs tend to expand and eventually rupture, resulting in a potentially fatal situation . The traditional strategies for managing VAAs are to follow-up by performing open surgical imaging or intervention exams. The classic surgical options include ligatures of the aneurysm with or without organ resection (for example, splenectomy) or aneurysmatic resection with revascularization .
Through the development of new techniques of minimally invasive intervention and the increased experience of endovascular surgeons, traditional treatment concepts have changed . Herein, we describe a rare case of pseudoaneurysm of the middle colic artery branch responsible for the intermittent digestive hemorrhage condition from an obscure source, diagnosed and successively treated by endovascular technique.
This report is on a male patient, 50 years old, who has a history of arterial hypertension and underwent a bariatric video laparoscopic surgery in 2009 (Fobi-Capella Technique) and who lost 40 kg in the past 6 years. An investigation for anemia has been performed since January 2016, when complaints of asthenia and melena were intercalated between normal appearance feces, 3 red blood concentrates were needed in February for symptomatic anemia. One colonoscopy in February displayed only diverticular disease. In March 2016, he was admitted to an emergency room due a history of bright red bleeding, asthenia, and lipothymia for 3 days. He denied abdominal pain, fever, or hematemesis. His vital signs displayed 100 × 70 mmHg arterial pressure, a 126 bpm heartbeat, and the absence of fever. The physical exam confirmed mucocutaneous pallor, there was no abdominal visceromegaly, and painless palpitation. The results from the hospital admission lab examinations were: 5.4 g/dL hemoglobin and 15% hematocrit, 1.09 INR, and 28s PTT. The patient was administered 2 red blood concentrates and an investigation for the digestive hemorrhage was carried out by performing a new colonoscopy confirming melena in the ileus and diverticular disease. The upper digestive endoscopy did not show any signs of bleeding. A scintigraphy was requested using marked red blood concentrates that verified the probable source of a bleeding site in the small intestines. The enteroscopy did not show any signs of bleeding, however in the validity period previous to the exam, the patient had not experienced any digestive bleeding for 1 week previously and not all intestinal segments were analyzed due to a previous surgery (gastric bypass, biliary bypass, and excluded stomach).
Due to the persistence of decreasing red blood cell count indexes and the need for frequent blood transfusions, an exploratory video laparotomy laparoscopy was chosen with a laparoscopic gastrostomy and intraoperative endoscopy to evaluate the excluded stomach and the proximal biliary bypass. However, bleeding was not confirmed during the procedure. A complete abdomen tomography was performed through oral contrast and intravenously that confirmed a lesion on the head and neck of the pancreas that was apparently complex cystic; it was difficult to characterize through a tomographic study including the possibility of a neoplastic or pseudo-cystic lesion (Figure 1). Nuclear magnetic resonance was performed for diagnostic complementation of the upper abdomen, demonstrating an oval shaped altered site with a T1 hyposignal and T2 hypersignal, including a minimum peripheral capturing through contrast that measured around 15 × 11 mm, compromising the transition between the pancreatic neck and head, with a small dilation of the Wirsung duct in the body/tail topography, studying the hypotheses of inflammatory pancreatopathy with pseudocyst, adenopathy, and primary neoplasia (Figure 2).
Figure 1: Tomography of the entire abdomen with intravenous contrast view displayed in axial cross-sections: A. Arterial phase. B. Venous phase. C. Late phase. Arrow head, hypodense image of the head topography, and the pancreatic neck; pointer, Wirsung duct slightly ectasiated. There is discrete highlighting after administrating the contrast that is more evident in the late cross sections.
Figure 2: Nuclear magnetic resonance of the upper abdomen: (A) Axial cross section of T1 with adipose saturation, pre-contrast phase; (B) Axial cross section of T1 with arterial phase adipose; (C) Axial cross section of T1 with portal phase adipose saturation; (D) Axial cross section with T1 with adipose saturation of balance phase. All these images display an oval-shaped lesion, with minimum peripheral capturing in the pancreas neck along its dorsal border. (E) Axial cross section of T2 with adipose saturation, image (arrow head) with hyper-signal to the neck level of the pancreas. (F) Coronal cross section of T1 with adipose saturation post-contrast displaying an oval-shaped lesion, with minimum peripheral capturing of the pancreas neck along its dorsal border (arrow head).
After 4 days without exteriorizing bleeding, as well as stable hematimetric indexes, new melena episodes occurred with a significant drop in hemoglobin levels to 4.8 g/dL and hematocrit 12%. After performing clinical stabilization measures, the patient was submitted to exploratory laparotomy with an intra-operatory enteroscopy without any sign of a bleeding site. The evolution relieved pain, achieved laboratorial stabilization, and stopped digestive bleeding. After 7 days, a new episode of digestive hemorrhage occurred; thereafter it was submitted to arteriography. A puncture provided access to the right femoral artery, utilizing a 6F introducer. A pseudoaneurysm was uncovered in the middle colic branch in the selective upper mesenteric arteriography using a micro-catheter (Figure 3A). No contrast overflow was observed during the procedure. The pseudoaneurysm treatment was performed using eleven micro-coils. The arteriography confirmed the aneurysm was completely excluded and the distal bed of the colic artery confirmed the aneurysm was completely excluded and the middle colic artery remained with collateral perfusion (Figure 3B).
There was optimal evolution, received medical release after the 3rd post-operatory. In the follow-up one month after the intervention, no new bleeding episodes occurred and the control angiotomography demonstrated the presence of radiopaque material from the embolization in the pancreaticoduodenal region, forming a rounded image measuring 15 × 15 mm and there were no evidences of overflow from the contrast medium (Figure 4).
Aneurysms of the middle colic artery and its branches are extremely rare and represent less than 3% of aneurysms of visceral arteries [5,6]. The majority of the series report an average age of 60 years old and an approximately equal distribution between genders [5-7].
There are 3 layers of vessels in true aneurysms (endothelium, muscularis and adventitia), the most common etiology is aterosclerose [2,8] and the symptoms are present in 70 to 90% of cases . Since false aneurysms or pseudoaneurysms are defined as missing complete arterial walls lined by adventitia or perivascular tissue and arises from the weakening of the arterial wall caused by trauma, including surgical trauma , or by proteolytic action as occurs in pancreatitis cases. Because of that, almost all cases of pseudoaneurysms are symptomatic and display greater risk of rupturing than true aneurysms [1,2].
The pathogenesis of bleeding is probably related to intermittent erosion and the wall destruction of the aneurysm due to contact with the duodenal wall, common bile duct, pseudocyst, or the Wiresung duct, secondary to the pressure necrosis caused by the expanding pseudoaneurysm [10,11]. The image studies of the present case demonstrated intimate contact with the pancreas and the Wirsung duct, simulating pancreatic lesion and even causing, ductal dilatation.
The diagnosis is rarely performed in asymptomatic patients, as it is frequent in those who manifest complications from aneurysms, especially rupturing, present in 90% of cases. In case of rupturing, the gastrointestinal hemorrhage is the most common clinical manifestation [11,12]. It can cause hematemesis, hemophilia, retroperitoneal hemorrhage, and hemorrhagic shock depending on the location [10,11], once it is broken, mortality can reach up to 70% . An aneurysm of a middle colic artery can display intermittent or slow hemorrhage that lasts for several months [5,6], as the clinical condition is manifested in this case.
Ultrasonography can reveal a hypoechoic cystic lesion strictly related to an artery. Doppler can display the typical entrance and leaving of blood described as a whirlwind movement in a bag through a neck (“yin-yang” sign) . The contrasted computerized tomography can show the aneurysm itself, or identify areas where there is bleeding hiding the aneurysm. We have shown the atypical appearance of a pseudoaneurysm, as it is not detected by contrast. The angiotomography supplies additional information on the pseudoaneurysm, as well as the disease process . The angiography is the gold standard for the diagnosis of pseudoaneurysms due to its capacity to evaluate in real time the location of an overflow. The anatomy of collateral vessels and the extension of affected vessels can be evaluated through this method [5,11,13]. The angiography is most sensitive (100%), followed by tomography (67%) and ultrasound (50%) [11,12].
Thus, a high degree of clinical and radiological suspicion is necessary in the interpretation of complementary exams in order to avoid wrong diagnoses. Since, the middle colic artery emerges from the upper mesenteric artery near the head of the pancreas to irrigate the transverse colon and occasionally the hepatic flexure of the colon , aneurysmatic dilations can be confused with pseudocysts, adenopathies, and even neoplasms involving the pancreas, as observed in this study. It is probable there will be episodes of pseudoaneurysm ruptures with bleeding to the Wirsung duct and the exteriorization of the digestive hemorrhage, followed by thrombosis, and periods of remission from the symptoms, thereby hindering and even confusing the diagnosis.
In the past, watchful waiting conduct was adopted, followed by ultrasonography, or the patients were then submitted to open surgery. In the last 20 years, due to advances in endovascular techniques, a new modality of treatment has arisen, as an alternative for open surgery, providing the advantage of reducing inherent morbidity and mortality of the procedure .
According to guidelines, the treatment of a true visceral aneurysm is recommended when its diameter is >2 cm or three times larger than the respective normal artery [11,15]. The treatment is also recommended in cases of rapid expansion >0.5 cm/year, symptoms, pregnant women, or those who are fertile, and patients submitted to hepatic transplant [11,14,16]. Conversely, pseudoaneurysms must be immediately treated as the rupture rate is much greater than true aneurysms (76.3% versus 3.1%) [11,17].
Endovascular management is safe and effective, including fewer complications, shorter hospital stay and recovery [4,18,19]. There are various methods for endovascular treatment, including the placement of coils, stent implantation, injection of polyvinyl alcohol particles, gelfoam or glue, and endoluminal thrombin injection [4,20,21]. Complications from these procedures are related to femoral cannulation, visceral infarction, and abscess, and more rarely organ necrosis, inadvertent and incorrect occlusion of a vessel, coil migration to other branches, infection, or aneurysmatic rupture during embolization . None of these complications have been observed in our work.
Treatment techniques used for each aneurysm must be individualized. Coil embolization is the most commonly utilized, especially in cases when the permeability of vessels is not imperious. There are various different options available for coil embolization, and their use depends on vascular anatomy and the aneurysm . The less invasive endovascular interventions must be priorities in the treatment of visceral aneurysms and pseudoaneurysms. As in case of any failure, there is the possibility of surgical rescue .
Visceral pseudoaneurysms must be considered among the diagnostic hypotheses in patients with a history of surgical manipulation or abdominal trauma and who have developed a digestive hemorrhage from an obscure source. Typical images of aneurysms may not be present when the symptomatology is intermittent, as they can confuse the diagnosis and delay treatment. Arteriography must not be delayed whenever a pseudoaneurysm is suspected accompanied by active bleeding, as that exam must be selected for the diagnosis and it is the chosen method for conclusive treatment.