Overview
Definition:
The Distal Splenorenal Shunt (DSRS), commonly known as the Warren shunt, is a surgical procedure creating a low-pressure pathway between the portal venous system and the systemic circulation
Specifically, it anastomoses the splenic vein to the left renal vein
This selective decompression of the portal venous system aims to reduce portal pressure and control gastroesophageal variceal bleeding while preserving splanchnic blood flow to the liver, unlike non-selective shunts.
Epidemiology:
Portal hypertension, primarily due to cirrhosis, is the leading cause of variceal bleeding worldwide
The incidence of variceal bleeding in patients with cirrhosis ranges from 25% to 60%
While Transjugular Intrahepatic Portosystemic Shunt (TIPS) has become a more common option, DSRS remains an important surgical consideration, especially in select patient populations.
Clinical Significance:
DSRS is a critical surgical intervention for managing refractory gastroesophageal variceal bleeding in patients with portal hypertension
Its selective nature distinguishes it from other portosystemic shunts, potentially offering advantages in preserving liver function and reducing the incidence of hepatic encephalopathy
Understanding its indications is paramount for surgical residents preparing for DNB and NEET SS examinations.
Indications
Refractory Variceal Bleeding:
Primary indication: Recurrent or intractable bleeding from esophageal or gastric varices that has failed to respond to endoscopic therapy (e.g., variceal ligation, sclerotherapy) and medical management (e.g., beta-blockers, octreotide).
Decompression Without Hepatic Dysfunction:
Patients with significant portal hypertension but who have relatively preserved liver function (Child-Pugh A or B) are ideal candidates, as non-selective shunts might exacerbate hepatic encephalopathy.
Absence Of Splenic Vein Thrombosis:
Patency of the splenic vein is essential for successful DSRS creation
Splenic vein thrombosis contraindicates this procedure.
Unsuitable For Tips:
Patients who are not candidates for TIPS due to anatomical limitations, severe coagulopathy unresponsive to correction, or a history of repeated TIPS failure may be considered for DSRS.
Specific Etiologies:
While cirrhosis is the most common cause of portal hypertension, DSRS can also be considered in other conditions like schistosomiasis or portal vein thrombosis where splenic vein remains patent and variceal bleeding is a problem.
Contraindications
Splenic Vein Thrombosis:
Complete or near-complete thrombosis of the splenic vein makes the shunt technically impossible and hemodynamically ineffective.
Severe Hepatic Dysfunction:
Patients with advanced liver disease (Child-Pugh C) have a higher risk of worsening hepatic encephalopathy and poor surgical outcomes with any portosystemic shunt.
Active Infection:
Presence of active systemic infection or intra-abdominal sepsis generally precludes elective major surgery.
Inability To Tolerate Major Surgery:
Patients with significant comorbidities that make them poor surgical candidates should not undergo DSRS.
Gastric Varices Without Esophageal Involvement:
While DSRS can help with gastric varices, it is primarily indicated when esophageal varices are also present and contributing to bleeding
Other surgical options might be considered for isolated gastric varices.
Preoperative Evaluation
Liver Function Tests:
Comprehensive assessment including LFTs, INR, albumin, and bilirubin to determine Child-Pugh classification.
Endoscopic Evaluation:
Upper GI endoscopy is mandatory to confirm the presence, grade, and location of varices and to rule out other sources of bleeding.
Imaging Studies:
CT angiography or MR venography to assess the patency of the portal vein, splenic vein, and hepatic veins, and to delineate anatomy for surgical planning.
Cardiac Evaluation:
Assessment of cardiac reserve, as patients with cirrhosis often have cardiovascular issues.
Surgical Technique Overview
Approach:
Typically performed via laparotomy, with potential for laparoscopic assistance in select centers.
Anastomosis:
Involves transecting the splenic vein distally and anastomosing it to the anterior surface of the left renal vein, usually end-to-side
The proximal splenic vein is ligated to divert flow to the liver via the portal vein.
Shunting Ratio:
The key feature is the selective decompression
the portal vein remains intact, allowing continued hepatic blood flow from the superior mesenteric vein
The right renal vein is also sometimes involved in variations of the technique.
Postoperative Considerations
Monitoring:
Close monitoring for bleeding, renal function, and development of hepatic encephalopathy
Serial endoscopies are often performed.
Management Of Encephalopathy:
Prophylaxis and management of hepatic encephalopathy are crucial, often involving dietary protein restriction, lactulose, and rifaximin.
Renal Function:
Monitoring for potential renal vein thrombosis or impaired renal function due to altered hemodynamics.
Key Points
Exam Focus:
DSRS is a SURGICAL intervention for refractory variceal bleeding
It's a SELECTIVE shunt aiming to preserve portal flow to the liver, unlike non-selective shunts (e.g., portocaval)
Key indication is failure of endoscopic and medical management
Contraindicated with splenic vein thrombosis or severe liver dysfunction.
Clinical Pearls:
Always confirm splenic vein patency pre-operatively
DSRS offers a theoretical advantage over TIPS in preserving liver function and reducing encephalopathy, but requires meticulous surgical skill
Hepatic encephalopathy management is critical post-operatively.
Common Mistakes:
Mistaking DSRS for TIPS
Forgetting to assess splenic vein patency
Not considering the impact of shunt creation on renal vein hemodynamics
Underestimating the risk of hepatic encephalopathy in patients with borderline liver function.