Relationship between total cholesterol and 90-day mortality after acute myocardial infarction in patients not on statins Rishi Parmar 2 nd year Medicine Resident

Introduction In most patients, there is a positive correlation between total cholesterol (TC) and long-term risk of myocardial infarctions (MI). However, in chronic heart failure patients, there is an inverse relationship between TC and mortality. In acute MI, most researchers have found no relationship between TC and mortality. We used the Optimal Trial in Myocardial Infarction with Angiotensin II Antagonist Losartan (OPTIMAAL) to evaluate the relationship between TC and survival at 90-days and the end of the study (median 2.7 years).

Study Population Of the 5,447 patients in the OPTIMAAL study, 5,206 patients were selected for our analysis based on our inclusion criterion that recorded values for the following variables: –Age, gender, Killip Class, ejection fraction, smoking history, past medical history of ischemic heart disease, Myocardial Infarction, Heart Failure, stroke, peripheral vascular disease, Chronic Obstructive Pulmonary Disease, diabetes, atrial fibrillation, Coronary Artery Bypass Grafting, angioplasty, TC, serum creatinine, and aspartate aminotransferase. Recorded values for the variables in the study were obtained at randomization, which was within 10 days of the acute MI.

Data Analysis Using the SPSS version 18.0, the study population was analyzed using the multivariate Cox models analysis Data was assessed for a linear or U- shaped relationship [(TC-nadir risk TC) 2 ] with all cause mortality

Population Characteristics The mean age was 67 years 71% of the patients being men 17% diabetics 30% statin users  Lower TC was associated with older age, male gender, Killip Class IV, lower AST, EF <35%, lower BP, history of ischemic heart disease, prior MI, diabetes, atrial fibrillation, prior cardiac bypass, and use of beta-blocker.

Hazard ratios (in mmol/L) between lipids and mortality at 90 days and end of study * Model adjusted for age, gender, and smoking, Killip class, log of serum AST, serum creatinine, systolic and diastolic blood pressure, heart rate, ischemic heart disease, MI, heart failure, stroke, peripheral vascular disease, chronic obstructive pulmonary disease, diabetes, atrial fibrillation, coronary artery bypass graft, angioplasty and use of aspirin, b-blocker, and thrombolytics at randomization.

Unadjusted relationship between TC and Mortality

The Hazard ratio of the U-shaped relationship between mortality and TC level at 90 days and end of study

Conclusions Our retrospective analysis of the OPTIMAAL database suggests that in patients not taking a statin at the time of acute MI there is a U-shaped relationship between TC and mortality. The nadir risk was at 250mg/dL (6.4 mmol/L) (Figure 2), with the relationship present as early as 90 days post MI. A 100 mg/dL increase or decrease from 250 mg/dL was associated with ~60% increase in mortality. In statin users, there was no relationship between TC and mortality. Statin use was associated with a 20% mortality reduction (multivariate p value =0.022) with the benefit appearing after 6 months.

Study Limitations The OPTIMAAL database doesn’t contain the inflammatory markers such as CRP that could help delineate the causes of the U-shaped relationship between TC and mortality.

Acknowledgements Team members: –Wayne Levy, MD (Mentor) –Alec Moorman, MD –Kenneth Dickstein, MD (Norway) –John Kjekshus, MD (Norway)