**Question:** In Forrest classification, high-risk of bleeding is associated with all except:

A. Moderate to severe thrombocytopenia
B. Prolonged international normalized ratio (INR)
C. Coagulation factor deficiency
D. Acquired von Willebrand disease

**Core Concept:** Forrest classification is a method used to predict the risk of bleeding during and after surgical procedures. It categorizes patients based on their coagulation profile and platelet count. The classification includes four groups: Group 1 - low risk, Group 2 - moderate risk, Group 3 - high risk, and Group 4 - very high risk.

**Why the Correct Answer is Right:** Group 4 (very high risk) includes patients with platelet count less than 20,000/mm³, significant coagulation factor deficiency, and severe thrombocytopenia (platelet count less than 10,000/mm³). All of these conditions contribute to an increased risk of bleeding.

**Why Each Wrong Option is Incorrect:**

**A**. Moderate to severe thrombocytopenia (platelet count less than 100,000/mm³) is included in Group 3 (high risk) due to its association with increased bleeding risk.

**B**. Prolonged INR (international normalized ratio) is only an indicator of liver function and does not directly relate to bleeding risk. While elevated INR may be associated with increased bleeding risk, it is not specific enough to exclude a patient from being in Group 3 or 4.

**C**. Coagulation factor deficiency is included in Group 3 (high risk) because it directly affects the clotting cascade, leading to impaired hemostasis and increased bleeding tendency.

**D**. Acquired von Willebrand disease is a bleeding disorder caused by a deficiency or dysfunction of von Willebrand factor, which plays a crucial role in platelet adhesion and function. It is included in Group 3 (high risk) due to its association with increased bleeding risk.

**Clinical Pearl**: Forrest classification helps clinicians to identify patients with high or very high risk of bleeding during and after surgery, allowing for appropriate preoperative planning and risk-adjusted management.