What is the Forrest classification of gastrointestinal (GI) bleeding?

Forrest Classification of Gastrointestinal Bleeding

The Forrest classification is an endoscopic scoring system that categorizes bleeding peptic ulcers based on their appearance and predicts the risk of rebleeding, need for intervention, and mortality. 1

Classification Categories

• Forrest Ia: Active spurting arterial bleeding - highest risk of rebleeding (59%) 1, 2
• Forrest Ib: Active oozing bleeding - lower risk of rebleeding compared to Ia 1
• Forrest IIa: Non-bleeding visible vessel - high risk of rebleeding 1, 3
• Forrest IIb: Adherent clot - moderate risk of rebleeding 1, 3
• Forrest IIc: Flat pigmented spot (hematin-covered lesion) - low risk of rebleeding 1, 3
• Forrest III: Clean ulcer base - lowest risk of rebleeding 1, 3

Clinical Significance and Management Implications

• Endoscopic hemostasis is strongly recommended for Forrest Ia, Ib, and IIa ulcers due to high risk of persistent bleeding or rebleeding 1, 3
• For Forrest IIb ulcers (adherent clot), clot removal should be considered with subsequent hemostasis if active bleeding or visible vessel is identified underneath 1, 3
• Forrest IIc and III ulcers have low rebleeding risk and generally do not require endoscopic hemostasis 1, 3
• Dual modality endoscopic hemostasis (mechanical therapy combined with epinephrine injection) is preferred over single modality for high-risk lesions 1

Risk Stratification Value

• The Forrest classification is more reliable for predicting rebleeding in gastric ulcers than duodenal ulcers 2
• Patients with Forrest Ia and IIa classifications include almost all patients at risk of further bleeding and death 4
• Some studies suggest the classification could potentially be simplified into high risk (Forrest Ia), increased risk (Forrest Ib-IIc), and low risk (Forrest III) categories 2

Documentation and Standardization

• Standard terminology and classification systems like the Forrest classification should be used when documenting endoscopic findings 5
• Proper photo-documentation of findings is essential for comparison in future examinations 5
• Inter-rater agreement among endoscopists for Forrest classification is generally good, with correlation higher among tutor and junior endoscopists than among experienced endoscopists 6

Common Pitfalls

• Epinephrine injection therapy should not be used as endoscopic monotherapy for high-risk lesions 3
• The Forrest classification may not be as applicable to post-endoscopic resection ulcers as it is to peptic ulcers 7
• Blind segmental resection without adequate localization of bleeding source leads to high rebleeding and mortality rates 8