What is the definition and management of a dominant stricture?

Dominant Stricture in PSC: Definition

A dominant stricture in primary sclerosing cholangitis (PSC) is defined at ERCP as a stenosis with a diameter of ≤1.5 mm in the common bile duct and/or ≤1.0 mm in a hepatic duct within 2 cm of the main hepatic confluence. 1

Formal Definition and Key Characteristics

• The ESGE/EASL consensus definition specifies stenosis diameter thresholds: ≥1.5 mm in the common bile duct and/or ≥1.0 mm in hepatic ducts within 2 cm of the hepatic confluence 1
• This definition was introduced by Stiehl et al. in 2002 as a severity measure for endoscopic studies, though it employs somewhat arbitrary values that depend on filling pressure 1
• Dominant strictures occur in 45-58% of PSC patients during follow-up and represent a frequent complication 1
• Multiple dominant strictures can coexist in the same patient (occurring in approximately 12% of cases) 1

Important Diagnostic Caveats

• This ERCP-based definition does not apply to MR cholangiography (MRC), particularly for extrahepatic ducts, due to insufficient spatial resolution of MRC and lack of hydrostatic pressure present during ERCP 1
• The diameter criterion alone should not determine clinical significance—the decision for intervention must be a compound clinical decision considering symptoms, biochemistry, and imaging findings together 1
• Many endoscopic studies do not apply the diameter criterion strictly and instead focus on suspected clinical relevance 1

Evolving Terminology: "Relevant Strictures"

• Recent EASL 2022 guidelines introduced the term "relevant strictures" to denote high-grade strictures (>75% reduction in duct diameter on MRI/MRCP) in the common bile duct or hepatic ducts that cause signs/symptoms of obstructive cholestasis and/or bacterial cholangitis 1
• This terminology shift acknowledges that morphologic findings alone (the word "dominant") should be distinguished from functional impairment requiring intervention 1
• On MRCP, experts now recommend using morphologic descriptors like "high-grade" or "severe" rather than "dominant" 1

Clinical Indications for ERCP Evaluation

ERCP with ductal sampling should be considered in established PSC when: 1

• Clinically relevant or worsening symptoms develop (jaundice, cholangitis, pruritus)
• Rapid increase in cholestatic enzyme levels occurs
• New dominant stricture or progression of existing dominant strictures identified on MRC with appropriate clinical findings

Malignancy Considerations

• Dominant strictures should always raise suspicion for cholangiocarcinoma (CCA), as this malignancy frequently presents as a stenotic ductal lesion in the perihilar region 1
• Despite this concern, stenotic lesions are far more often benign than malignant in nature, though CCA develops in approximately 10-15% of PSC patients 1
• Brush cytology and/or endoscopic biopsy must be obtained before any therapeutic intervention to help exclude superimposed malignancy 1

Management Approach

• Balloon dilation alone is the preferred first-line endoscopic therapy for dominant strictures, with lower complication rates (15% vs 54%) compared to stenting 2, 3
• Stenting should be reserved for strictures refractory to balloon dilation alone 2
• Prophylactic antibiotics should be administered routinely before ERCP in PSC patients due to risk of cholangitis 2
• Therapeutic intervention is recommended for patients with relevant strictures causing signs/symptoms of obstructive cholestasis and/or bacterial cholangitis 1

Recent Evidence on Clinical Significance

• A 2024 study found that strictures meeting the new definition (NDS) occurred in 17% of PSC patients and identified those with more advanced disease, biliary inflammation, and greater need for endoscopic therapy (81% required dilation, 21% required stenting) 4
• Patients with NDS were more symptomatic, had higher cholestatic liver enzymes, and more advanced bile duct disease compared to those with traditional dominant strictures 4