Background:
There haven’t been well-designed studies conducted to know an optimal goal for low-density lipoprotein cholesterol (LDL-C) after acute myocardial infarction (AMI).
Methods:
Of 2,409 consecutive patients (62.7 ± 12.4 years, 74.1% men) with AMI who had baseline LDL-C levels ≥70mg/dL and received discharge statin prescriptions after successful percutaneous coronary intervention, 1,305 patients (61.0 ± 11.8 years, 77.0% men) who had LDL-C levels tested at 1 year (mean baseline LDL-C, 126.5 ± 33.5 mg/dL; mean LDL-C reduction at 1 year, 53.1 ± 29.3 mg/dL) were analyzed in this study. Patients were categorized into 2 groups according to the values of LDL-C at 1 year in two different ways using percent change from baseline (≥50% reduction, n=428 versus <50% reduction, n=877) and fixed levels (<70 mg/L, n=625 versus ≥70 mg/dL, n=680). The primary endpoint was the composite of major cardiac events (MCEs) including cardiac deaths, non-fatal myocardial infarctions and coronary revascularizations (angioplasty or bypass grafting) after hospital discharge. A median follow-up duration was 2.0 years (interquartile range, 1.9 to 2.1 years).
Results:
At 2 years, MCEs occurred in 139 patients (10.7%). Kaplan-Meier estimates of the MCEs rates at 2 years revealed that patients with ≥50% LDL-C reduction from baseline had fewer MCEs compared with <50% LDL-C reduction (8.2% versus 11.9%; Log rank
P
=0.026), while those with LDL-C levels <70 mg/dL at 1 year did not (<70 mg/L, 10.7% versus ≥70 mg/dL, 10.6%; Log rank
P
=0.998). In a multivariable Cox proportional hazard model, patients with ≥50% LDL-C reduction from baseline had a 39% reduction in the risk of MCEs compared with <50% LDL-C reduction (adjusted hazard ratio [HR], 0.61; 95% confidence interval [CI], 0.41 to 0.90;
P
=0.012). But, compared with LDL-C levels ≥70 mg/dL at 1 year, patients with LDL-C levels <70 mg/dL didn’t have a significant reduction in the risk of MCEs (adjusted HR, 0.98; 95% CI, 0.69 to 1.37;
P
=0.975).
Conclusions:
Obtaining a ≥50% reduction in LDL-C was associated with a significant reduction in the risk of MCEs after AMI, whereas achieving a <70 mg/dL was not. Our study suggests that obtaining a ≥50% reduction from baseline could be an optimal goal for LDL-C after AMI, not achieving a <70 mg/dL.
Low-Density Lipoprotein Cholesterol Level and Statin Therapy in Patients With Acute Myocardial Infarction (Cholesterol Paradox)
