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

Abstract

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, apoB₁₀₀, 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.

Keywords: ApoCII; Apolipoprotein-CII; Mass spectrometry; Premature coronary artery disease; ST-segment elevation myocardial infarction.