What should the LDL target be in patients with prediabetes and high lipoprotein (a) with family history of coronary artery disease?   

While there is no clear guidance to answer this question, a patient meeting this profile should be considered high risk. I would first start by calculating the 10-year ASCVD risk, which will depend on the patient's classic ASCVD risk profile (age, sex, race, cholesterol, HDL, BP, and HTN, Diabetes, ...