A huge intrahepatic portal vein aneurysm

Understanding the Pathophysiology of Portosystemic Shunt by Simulation Using an Electric Circuit

Portosystemic shunt (PSS) without a definable cause is a rare condition, and most of the studies on this topic are small series or based on case reports. Moreover, no firm agreement has been reached on the definition and classification of various forms of PSS, which makes it difficult to compare and analyze the management. The blood flow can be seen very similar to an electric current, governed by Ohm's law. The simulation of PSS using an electric circuit, combined with the interpretation of reported management results, can provide intuitive insights into the underlying mechanism of PSS development. In this article, we have built a model of PSS using electric circuit symbols and explained clinical manifestations as well as the possible mechanisms underlying a PSS formation.

Portal vein aneurysm: What to know

Portal vein aneurysm is an unusual vascular dilatation of the portal vein, which was first described by Barzilai and Kleckner in 1956 and since then less than 200 cases have been reported. The aim of this article is to provide an overview of the international literature to better clarify various aspects of this rare nosological entity and provide clear evidence-based summary, when available, of the clinical and surgical management. A systematic literature search of the Pubmed database was performed for all articles related to portal vein aneurysm. All articles published from 1956 to 2014 were examined for a total of 96 reports, including 190 patients. Portal vein aneurysm is defined as a portal vein diameter exceeding 1.9 cm in cirrhotic patients and 1.5 cm in normal livers. It can be congenital or acquired and portal hypertension represents the main cause of the acquired version. Surgical indication is considered in case of rupture, thrombosis or symptomatic aneurysms. Aneurysmectomy and aneurysmorrhaphy are considered in patients with normal liver, while shunt procedures or liver transplantation are the treatment of choice in case of portal hypertension. Being such a rare vascular entity its management should be reserved to high-volume tertiary hepato-biliary centres.

Visceral venous aneurysms: clinical presentation, natural history and their management: a systematic review

AIM

Aneurysms of the visceral veins are considered rare clinical entities. The aim is to assess their clinical presentation, natural history and management.

METHODS

An electronic search of the pertinent English and French literature was undertaken. All studies reporting on aneurysms of visceral veins were considered. Cases describing patients with arterial-venous fistulae and extrahepatic or intra-hepatic portosystemic venous shunts were excluded.

RESULTS

Ninety-three reports were identified, including 176 patients with 198 visceral venous aneurysms. Patients' age ranges from 0 to 87 years, and there is no apparent male/female preponderance. The commonest location of visceral venous aneurysms is the portal venous system (87 of 93 reports, 170 of 176 patients, 191 of 198 aneurysms). Aneurysms of the renal veins and inferior mesenteric vein are also described. Portal system venous aneurysms were present with abdominal pain in 44.7% of the patients, gastrointestinal bleeding in 7.3%, and are asymptomatic in 38.2%. Portal hypertension is reported in 30.8% and liver cirrhosis in 28.3%. Thrombosis occurred in 13.6% and rupture in 2.2% of the patients. Adjacent organ compression is reported in 2.2% (organs compressed: common bile duct, duodenum, inferior vena cava). The management ranged from watchful waiting to intervention. In 94% of the cases, aneurysm diameter remained stable and no complications occurred during follow-up. In most of the cases, indications for operation were symptoms and complications. Six cases of renal vein aneurysm are reported; three of them were asymptomatic. Three of these patients were treated surgically.

CONCLUSION

The most frequent location of visceral venous aneurysms is the portal venous system. They are often associated with cirrhosis and portal hypertension. They may be asymptomatic or present with abdominal pain and other symptoms. Watchful waiting is an appropriate treatment, except when complications occur. Most common complications are aneurysm thrombosis and rupture. Other visceral venous aneurysms are extremely rare.

Computer Simulation of Hemodynamic Changes After Right Lobectomy in a Liver with Intrahepatic Portal Vein Aneurysm

BACKGROUND/PURPOSE

Intrahepatic portal vein aneurysm is rare and its natural history is unknown. A 22-year-old healthy man, who wished to donate part of his liver to his diseased father, was incidentally diagnosed to have an intrahepatic portal vein aneurysm. The surgical decision of performing live donor hepatectomy for such a patient is normally difficult. We combined modern imaging reconstruction technologies with scientific computing as a new modality to foresee the risks of surgical complications.

METHODS

Cross-sectional computed tomography images were used to reconstruct the three-dimensional image of portal vein distribution using the 3D-Doctor v3.5 software. The reconstructed images were further employed to generate surface and interior meshes with CFX software. Simulated hemodynamic changes in velocity, pressure, and wall stress were determined for the right lobectomy case pre- and postoperatively.

RESULTS

The simulation results indicated that aneurismal pressure would be elevated significantly to 12.03 mmHg after operation. The left segmental portal venous blood flow would increase from 2.95- to 4.25-fold. The area near the branch point of one left segmental portal vein, which supplies blood to liver segment 4, and the portal vein aneurysm would endure high shear stress gradient. The resulting elevated aneurismal pressure may cause the thin wall to enlarge and rupture, while the high shear stress gradient would lead to vascular endothelial cell injury. Living donor surgery was not recommended hemodynamically based on the simulated results.

CONCLUSION

Scientific computing and modern imaging technologies can be applied together to aid surgeons to make the best decision in difficult clinical situations.