Table 1.

List of risk factors responsible development of various biliary complications

Risk factor	Mechanism	Resultant biliary complication
HAT or stenosis	Being the main vascular supply to the bile duct, any compromise to integrity of HA or its branches induces acute and chronic ischemia of the biliary system	Anastomotic disruption Bile leak NAS AS Biliary cast syndrome
Type of transplant	Live-donor LT has higher overall biliary complications compared to Orthotopic LT	Bile leak HAT Unplanned re-explorations Portal vein thrombosis
Type of donor	DCD LT has higher biliary complication rate compared to DBD LT. This is because of increased risk of experiencing insufficient organ perfusion. Also increased risk if ABO blood group incompatibility between donor and recipient	Strictures (NAS) Bile duct filling defects (stones/sludge/clots/casts)
Type of anastomosis (biliary reconstruction)	Duct-to-duct CC anastomosis is preferred whenever possible, being simple and prevents enteric reflux into bile ducts, compared to RYC	Comparative biliary complication data is conflicting
Graft related factors	Use of grafts from older donors or grafts with increased steatosis (extended criteria), as well as increased cold (CIT) and warm ischemia times	Strictures (NAS and AS) Bile leak Bile duct filling defects (stones/sludge/clots/casts)
Surgical (or technical) factors-during both donor and recipient surgeries	Excessive dissection of periductal tissue during the procurement of native liver Excessive electrocautery to control bleeding during surgery Tension between the two ends of the biliary anastomosis Suture material used Denervation or injury to sphincter	Bile leak AS Mucocele Sphincter of Oddi Dysfunction
Placement of T-tubes (old strategy)	This increases chances of delayed healing, and may cause bile leaks.	Bile leak Hemobilia Infections (Cholangitis and Peritonitis)
Pre-LT factors	Infections (CMV or intra-abdominal infections) Diagnosis for LT: PSC or AIH	Infections (Cholangitis and Peritonitis) Strictures (NAS and AS) Bile duct filling defects (stones/sludge/clots/casts)
Post-LT factors	Immunosuppression: Emerging evidence that Sirolimus based regimen have higher risk of biliary strictures Infection, Acute cellular rejection, Obstruction, etc. Post-operative small bile leak is risk factor for future strictures Early HCV recurrence post-LT also increases inflammation and hence risk of strictures	Strictures (NAS and AS) Biliary cast syndrome

HAT: Hepatic Artery Thrombosis; NAS: Non-anastomotic stricture; AS: Anastomotic stricture; DCD: Donor after cardiac death; DBD: Donor after brain death; CC: Choledocho-choledochostomy; RYC: Roux-en-Y choledochojejunostomy.