By Jeyashree Sundaram, MBA
Gastric varices (GV) are enlarged submucosal veins that are capable of causing hazardous bleeding at the upper gastrointestinal tract. Generally, GV are identified in patients suffering from portal hypertension or high pressure in the vein portal system. Based on the cause, GV occur due to STV (splenic vein thrombosis) and portal hypertension.
Usually in the setting of SVT, GV develop in the occurrence of pancreatitis or local neoplasm in the absence of portal venous hypertension. The occurrence of GV because of SVT, however, is minimum when compared to that occurs as a result of portal hypertension. Short gastric veins – the veins which run from the spleen’s hilum to the abdomen’s greater curvature – are locations from which GV that occur because of SVT originates.
The Sarin classification is defined as the most helpful classification system in differentiating the gastric varices. This classification is done through the endoscopic identification of the location and appearance of the varices. This endoscopic examination is also useful in understanding the orientation of varices in the stomach and distal esophagus.
According to Sarin classification, the gastric varices are divided into four types based on their location in the stomach and its association with the esophageal varices. The four different types of gastric varices are as follows.
- Type 1 gastroesophageal varix (GOV): These varices extend over the cardia and lesser curvature of the abdomen that ends in gastric fundus.
- Type 2 gastroesophageal varix: GOV2 extends ahead of the cardia and leads towards the greater curvature of the abdomen and to the gastric fundus.
- Type 1 Isolated gastric varix (IGV): These varices exist in the gastric fundus and they do not extend into the esophagus or the cardia.
- Type 2 Isolated gastric varix: It is defined as ectopic varices that occur in other parts of the stomach.
GOV is the frequent and the most common type of gastric varices. It has been reported that about 74% of overall gastric varices are identified with type 1 GOV. However, the frequency of bleeding is greater in isolated gastric varix types and type 2 gastroesophageal varix. Sarin’s classification is widely recognized as a helpful perspective to identify and analyze the gastric varices. But it often fails to interact with the bottom-line vascular anatomy. The fundal GV originate in a portion or in complete from of gastrorenal shunts or spleno shunts, which is known as the left-sided (Sinistral) portal hypertension.
Impact of Sarin Classification
The formation of GEV1 occurs when the gastric veins pierce the cardiac vein or gastric wall. The pierced veins now get connected to the submucosal veins present in the gastric zone that is directly linked to the submucosal veins at the palisade zone. The large esophageal varices and the GEV1 are completely interlinked to each other, but only 50% of the GEV2 is linked with large esophageal varices. On the other hand, the isolated gastric varices (IGV1) are related to the segmental portal hypertension or with the collaterals through the vein in the spleen that extends till renal vein. This process is mainly because to enable blood flow through the varices.
With the help of gastrophrenic shunts, gastrorenal shunts, and gastropericardiac shunts, the blood flow through IGV1 will get collected into the inferior phrenic. In addition, some portions of the IGV1 get projected in the intragastric space. For about 50% of the cases of ectopic varices that include IGV2 are closely related with the portal vein thrombosis. The system that is responsible for this occurrence is not yet identified. With the help of portovenography, it has been discovered that about 70% of the left gastric vein takes part in the blood supply of the IGV1. In contrast, the participation of left gastric veins in esophageal varices is 100%.
But in the isolated gastric varices, 70% of the posterior gastric vein takes part in the blood supply, and in esophageal varices, it is 24%. Hemiazygos and azygos veins are the essential blood drainage routes for the patients with esophageal varices. All the veins present in the cardiac varices will get drained into the esophageal varices. The ultimate drainage path for the isolated gastric varices is gastrophrenic shunt (10%), gastropericardiac shunt (5%), and gastrorenal shunt (85 %).
General Classification Notes of Sarin
The varices classifications are strictly applicable to the primary evaluation only before the therapy. After treatment, classification for the varices is highly difficult. For post-treatment classification, the description of the location, diameter, sign, and number of residual varices are taken into consideration. The endoscopic ultrasound (EUS) is helpful in witnessing the small vessels that are present in the wall. If the endoscopic results are declared to be uncertain, then the EUS plays an important role in demonstrating the residual flow.