Forrest Classification and PPI Therapy in Bleeding Peptic Ulcers
Role of Forrest Classification in Guiding PPI Therapy
The Forrest classification directly determines both the need for endoscopic intervention and the intensity of PPI therapy, with high-risk lesions (Forrest Ia, Ib, IIa, and IIb) requiring immediate endoscopic hemostasis followed by high-dose intravenous PPI (80 mg bolus + 8 mg/hour infusion for 72 hours), while low-risk lesions (Forrest IIc and III) require only standard oral PPI therapy without endoscopic intervention. 1
Forrest Classification Categories and Management
High-Risk Lesions Requiring Aggressive Therapy
Forrest Ia (Spurting arterial bleeding): Highest rebleeding risk at 59%, requires immediate dual-modality endoscopic hemostasis plus high-dose IV PPI 2, 3, 4
Forrest Ib (Oozing bleeding): Paradoxically has lower rebleeding risk than Forrest IIa and IIb lesions despite active bleeding, but still requires endoscopic therapy and high-dose PPI 1, 4
Forrest IIa (Visible vessel): High rebleeding risk requiring endoscopic hemostasis and high-dose PPI, with Doppler studies showing higher arterial flow than Forrest Ib lesions 1, 4
Forrest IIb (Adherent clot): Requires vigorous irrigation for at least 5 minutes to expose underlying stigmata; if high-risk stigmata are revealed (occurs in 70% of successfully dislodged clots), treat with endoscopic therapy and high-dose PPI 5, 4
Low-Risk Lesions Requiring Medical Therapy Only
Forrest IIc (Flat pigmented spot): Does not require endoscopic hemostasis; manage with standard oral PPI therapy, though patients with Rockall score ≥6 have increased rebleeding risk (18.6% vs 2.9%) and warrant closer monitoring 5, 6
Forrest III (Clean base): Lowest rebleeding risk at 5%, requires only standard oral PPI without endoscopic intervention 5, 4
PPI Regimen Based on Forrest Classification
For High-Risk Lesions (Forrest Ia, Ib, IIa, IIb)
Initiate PPI therapy as soon as possible, ideally before endoscopy 1, 7
After successful endoscopic hemostasis, administer 80 mg IV bolus followed by 8 mg/hour continuous infusion for 72 hours, which reduces rebleeding from 10.3% to 5.9% (p=0.03) and decreases need for repeat endoscopy 1, 7
Transition to oral PPI 40 mg twice daily for days 4-14, which reduces rebleeding risk by 63% compared to once-daily dosing (RR 0.37, CI 0.19-0.73) 8
Continue oral PPI 40 mg once daily for total duration of 6-8 weeks following endoscopic treatment 1, 8
For Low-Risk Lesions (Forrest IIc, III)
Standard oral PPI therapy (20-40 mg once daily) for 6-8 weeks is sufficient without high-dose IV regimen 5, 8
Early discharge is appropriate for patients with low-risk lesions and no comorbidities 5
Critical Limitations of Forrest Classification
Doppler probe assessment is superior to Forrest classification for predicting rebleeding risk, with Doppler-guided hemostasis reducing 30-day rebleeding rates (NNT=7) 1, 9
The Forrest classification has significant intra- and inter-observer variability, limiting its reliability, particularly for duodenal ulcers compared to gastric ulcers 2, 9
Forrest Ib lesions have lower rebleeding risk than Forrest IIa and IIb despite representing active bleeding, highlighting that the classification does not perfectly correlate with rebleeding risk 1
The Forrest classification does not predict mortality, only rebleeding risk, so clinical factors (Rockall score) must be incorporated for comprehensive risk assessment 6, 2
Common Pitfalls to Avoid
Never use epinephrine injection alone for high-risk lesions—it must be combined with mechanical or thermal therapy, as monotherapy provides suboptimal efficacy 5
Do not aggressively mechanically dislodge Forrest IIb clots—use cautious irrigation-based approaches for at least 5 minutes, as aggressive dislodgment increases perforation risk 1, 5
Do not skip endoscopy in favor of PPI therapy alone for high-risk lesions—PPI is adjunctive therapy, not a replacement for endoscopic hemostasis 7
Do not discharge patients with high-risk lesions before 72 hours—60-76% of rebleeding episodes occur within this timeframe 8