This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Medicine
[{'content': 'Poal hypeension is defined as, hepatic venous pressure gradient (HVPG) greater than \nSelect and explain. \nA. 5 mm of hg, B. 10 mm of Hg, C. 15 mm of Hg, D. 20 mm of Hg', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Poal hypeension is defined as the elevation of the hepatic venous pressure gradient (HVPG) to >5 mmHg. Poal hypeension is caused by a combination of two simultaneously occurring hemodynamic processes: 1) Increased intrahepatic resistance to the passage of blood flow through the liver due to cirrhosis and regenerative nodules, and 2) Increased splanchnic blood flow secondary to vasodilation within the splanchnic vascular bed. Poal hypeension is directly responsible for the two major complications of cirrhosis: variceal haemorrhage and ascites.Ref: Harrison 19e pg: 2063', 'role': 'assistant'}]