Low-Density Lipoprotein Cholesterol Level in Patients With Acute Myocardial Infarction Having Percutaneous Coronary Intervention (the Cholesterol Paradox)

The relation between low-density lipoprotein (LDL) cholesterol levels and clinical outcomes after percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI) has not been described. A total of 9,571 eligible patients (mean age 62.6 ± 12.5 years, 6,967 men) who underwent PCI with a final diagnosis of AMI from the Korea Acute Myocardial Infarction Registry (KAMIR) were divided into 5 groups according to LDL cholesterol level: <70, 70 to 99, 100 to 129, 130 to 159, and ≥160 mg/dl. Clinical outcomes in hospital and 1 and 12 months after PCI in patients with AMI were examined. Age and co-morbidities decreased as LDL cholesterol increased. Patients with higher LDL cholesterol levels had favorable hemodynamic status and laboratory findings. Lifesaving medications, including lipid-lowering drugs, were underused in patients with lower LDL cholesterol levels. Clinical outcomes in hospital and 1 and 12 months after PCI showed better results as LDL cholesterol increased, except for patients with LDL cholesterol levels ≥160 mg/dl. In a Cox proportional-hazards model, LDL cholesterol level was not an independent predictor of mortality at 12 months, after adjusting for clinical characteristics including demographics and biologic data. In conclusion, the cholesterol paradox in patients with AMI is related to confounding by baseline characteristics associated with survival. More intensive treatment including lipid-lowering therapy for AMI in patients with lower LDL cholesterol level may result in better clinical outcomes.