What is the Forrest grade and how is it used to manage upper gastrointestinal bleeding in adults with a history of peptic ulcer disease?

Forrest Classification: Definition and Clinical Application in Upper GI Bleeding

What is the Forrest Classification?

The Forrest classification is an endoscopic scoring system that categorizes bleeding peptic ulcers based on their appearance at endoscopy and directly predicts rebleeding risk, need for intervention, and guides management decisions. 1, 2

The classification divides ulcers into three main categories with specific rebleeding risks:

Forrest I: Active Bleeding

• Forrest Ia (Spurting arterial bleeding): Highest rebleeding risk at 55-59% without treatment 2, 3
• Forrest Ib (Oozing bleeding): Rebleeding risk of approximately 10-27% 1, 2

Forrest II: Recent Hemorrhage Stigmata

• Forrest IIa (Non-bleeding visible vessel): High rebleeding risk of 43-50% 1, 4
• Forrest IIb (Adherent clot): Rebleeding risk of 22-33% 1, 4
• Forrest IIc (Flat pigmented spot): Low rebleeding risk of 7-10% 2, 4

Forrest III: Clean Base

• Forrest III (Clean ulcer base): Lowest rebleeding risk at <5% 2, 5

Management Algorithm Based on Forrest Classification

High-Risk Lesions Requiring Immediate Endoscopic Hemostasis

For Forrest Ia, Ib, and IIa ulcers, endoscopic hemostasis is mandatory and should utilize dual-modality therapy combining mechanical therapy (clips or thermal coagulation) with epinephrine injection. 1, 2

Management steps:

• Perform urgent endoscopy within 12 hours for high-risk patients with hemodynamic instability 1, 4
• Apply dual-modality hemostasis: mechanical therapy (clips/thermal) PLUS epinephrine injection, which reduces rebleeding (OR 0.19,95% CI 0.07-0.52) and need for surgery (OR 0.10,95% CI 0.01-0.50) 2
• Never use epinephrine injection alone—it provides inadequate hemostasis and must be combined with mechanical or thermal therapy 2, 4
• Administer high-dose PPI: 80 mg IV bolus followed by 8 mg/hour continuous infusion for 72 hours, which reduces rebleeding from 10.3% to 5.9% 1, 2

Intermediate-Risk Lesions (Forrest IIb)

For adherent clots, perform vigorous irrigation with water pump for at least 5 minutes to dislodge the clot and expose underlying stigmata. 2, 4

Management approach:

• If irrigation reveals high-risk stigmata (Ia, Ib, or IIa), treat according to high-risk protocol 2, 4
• In high-risk patients (hemodynamic instability, serious comorbidities, ongoing NSAID use), endoscopic therapy reduces rebleeding from 24.7% to 8.2% (NNT = 6.3) 2
• Avoid aggressive mechanical dislodgment without preparation, as this increases perforation risk 2
• Continue high-dose PPI therapy (80 mg bolus then 8 mg/hour infusion for 72 hours) even if clot is not removed 4

Low-Risk Lesions (Forrest IIc and III)

For flat pigmented spots and clean-based ulcers, endoscopic hemostasis is not indicated; manage with standard oral PPI therapy alone. 1, 5, 4

Management protocol:

• Initiate oral PPI once-daily 5, 4
• Early feeding within 24 hours is safe 5
• Discharge with outpatient follow-up is appropriate for patients without significant comorbidities 1, 5
• For gastric ulcers specifically, perform surveillance endoscopy at 6 weeks to confirm healing and exclude malignancy with biopsies 5

Risk Stratification Integration

Combine Forrest classification with the Blatchford score for comprehensive risk stratification: 1

• Very low risk (Blatchford 0-1): Outpatient endoscopy acceptable 1
• Low risk (Blatchford 2-6): Early inpatient endoscopy within 24 hours 1
• High risk (Blatchford ≥7): Urgent inpatient endoscopy within 12 hours 1

Management of Rebleeding

If rebleeding occurs after initial successful hemostasis, perform repeat endoscopy with hemostasis as the first-line approach. 4

Escalation pathway:

• First rebleed: Repeat endoscopic hemostasis 4
• Second endoscopic failure: Consider transcatheter angiographic embolization or surgery 1, 4
• Seek surgical consultation when endoscopic therapy fails 1

Essential Adjunctive Management

All patients with peptic ulcer bleeding require:

• H. pylori testing with eradication therapy if positive, and confirmation of eradication 1
• Negative H. pylori tests in acute setting should be repeated, as false-negative rates reach 25-55% during active bleeding 1
• For patients on aspirin for cardiovascular prophylaxis: resume immediately after endoscopy for low-risk lesions (IIc, III), or by day 3 for high-risk lesions if adequate hemostasis achieved 4
• Continue PPI therapy for 6-8 weeks following endoscopic treatment 2

Critical Limitations and Pitfalls

The Forrest classification has important limitations that must be recognized: 2, 3

• Forrest Ib lesions paradoxically have lower rebleeding risk than Forrest IIa and IIb despite representing active bleeding 2
• The classification predicts rebleeding more reliably for gastric ulcers than duodenal ulcers 3
• Doppler probe assessment, when available, provides superior risk stratification beyond Forrest classification alone and reduces 30-day rebleeding rates (NNT = 7) 1, 2
• The Forrest classification does not predict mortality—clinical factors (age >65, shock, comorbidities) must be incorporated for mortality risk assessment 3