Low levels of apolipoprotein-CII in normotriglyceridemic patients with very premature coronary artery disease: Observations from the MISSION! Intervention study

Background While the overall acute myocardial infarction rates declined in women and men, premature acute myocardial infarction rates remained stable in men and increased in women. Objective The purpose of this study was to assess whether baseline apolipoprotein (apo) levels, clinical characteristics, and follow-up of patients with very premature coronary artery disease (CAD) could provide novel clues for the identification of high-risk individuals. Methods Apos were measured with a validated quantification liquid chromatography–mass spectrometry method in a well-defined cohort of 38 patients aged ≤45 years admitted with acute ST-segment elevation myocardial infarction. Results Mean age was 39.8 ± 4.6 years and 24% was female. Four of these patients (11%) had apoCII levels ≤5.0 mg/L. Compared with the very premature CAD group with apoCII > 5 mg/L, the patients with apoCII levels ≤5.0 mg/L were all females, tended to be younger (35.8 ± 8.4 years vs 40.3 ± 3.9 years, P  = .063), had more often a family history of cardiovascular disease ≤65 years ( P  = .034) and a significantly lower Framingham risk score ( P  = .001). They presented with normal triglyceride levels, and had lower low-density lipoprotein cholesterol, apoB 100 , and apoE levels. Corrected for differences in risk profile, apoCII ≤ 5 mg/L was associated with increased risk of 10-years reinfarction or revascularization (hazard ratio 7.9 [95% confidence interval 1.5–41.6], P  = .015). Conclusions In 38 patients with very premature CAD, 11% were found to have low apoCII levels (≤5.0 mg/L) with normal triglyceride levels. Despite their low a priori risk for CAD, these patients presented with ST-segment elevation myocardial infarction and had a high relative risk of 10-year reinfarction or revascularization. This particular phenotype of relatively young female patients with CAD is not recognized earlier and deserves further study.