Association of serum levels of lipoprotein A-I and lipoprotein A-I/A-II with high on-treatment platelet reactivity in patients with ST-segment elevation myocardial infarction

Objective: High-density lipoproteins (HDLs) are a very heterogeneous group of particles. Little is known about the impact of their subfractions including lipoprotein A-I (LpA-I) and lipoprotein A-I/A-II (LpA-I/A-II) on platelet function and high on-treatment platelet reactivity (HPR), particularly in the acute phase of ST-segment elevation myocardial infarction (STEMI). The aim of the study was to evaluate the relationship between serum levels of LpA-I and LpA-I/A-II and HPR in STEMI patients. Methods: Fifty-two consecutive STEMI patients (26.9% women, mean age 60.6±9.1 years) were enrolled into this study. Clinical and demographic data were collected and HDL subfractions were measured by rocket immunoelectrophoresis. Platelet reactivity was assessed using light transmission aggregometry and quantitative flow cytometry. Results: We found a positive correlation between platelet aggregation after both ADP-5 and ADP-20 stimulation and serum level of LpA-I. Compared with subjects with satisfactory platelet response to clopidogrel, patients with HPR had 32.44% higher serum level of LpA-I (p=0.021). On the other hand, patients with HPR assessed by ADP-5 stimulation had 22.13% lower serum level of LpA-I/A-II (p=0.040). Regression analysis showed that LpA-I [odds ratio (OR) 1.03; 95% confidence interval (CI) 1-1.07; p=0.049] and current smoking (OR 0.18; 95% CI 0.04-0.81; p=0.025) were independent predictors of HPR. With receiver operating characteristic (ROC) curve analysis, we designated the cut-off point at serum level of 57.52 mg/dL for LpA-I for predicting HPR (AUC=0.71, p=0.010). Conclusion: This study showed that higher serum level of LpA-I measured in the acute phase of STEMI is an independent risk factor for HPR. Our study is the first to demonstrate an important and distinct activity of LpA-I and LpA-I/A-II that can prove pleiotropic and different functions of HDL subfractions in acute STEMI. (Anatol J Cardiol 2018; 19: 374-81

Selenium deficiency and the dynamics of changes of thyroid profile in patients with acute myocardial infarction and chronic heart failure

Background: Selenium (Se) is incorporated in 25 enzymes, for example, glutathione peroxidase (activatedb by oxidative stress) and deiodinases (converting thyroid hormones). Oxidative stress present in heart failure (HF) and myocardial infarction (MI) might cause Se deficiency and decreased thyroxine to triiodothyronine conversion. Aims:  We sought to evaluate Se levels in Polish patients with MI, HF, and healthy volunteers in relation to thyroid hormone levels. Methods: The study group consisted of 143 participants: 54 patients with MI, 59 patients with decompensated HF, and 30 healthy matched volunteers. The patients underwent echocardiography and laboratory tests on admission and 5 months later. Results: Se levels were lower in patients with MI and HF than in controls (median [interquartile range, IQR], 65.9 [55.2–76.1] μg/l and 59.7 [47.7–70.7] μg/l vs 93.2 [84.2–99.1] μg/l, respectively; P < 0.001). The Se deficiency was very common in patients with MI and HF, while it was rare in controls (70.37% and 74.58% vs 10%, respectively; P < 0.001). Patients with MI and HF presented lower free triiodothyronine (FT3) levels and lower FT3 to free thyroxine (FT4) ratio in comparison with controls (median [IQR], 3.90 [3.60–4.38] pmol/l and 4.25 [3.57–4.60] pmol/l vs 4.92 [4.50–5.27] pmol/l; P < 0.001; and 0.25 [0.23–0.29] and 0.25 [0.21–0.28] vs 0.32 [0.29–0.37]; P < 0.001, respectively). There was a weak to moderate correlation between Se level, FT3 level, and the FT3/FT4 ratio. At follow‑up, the FT3/FT4 ratio tended to normalize in patients with MI and remained decreased in patients with HF (mean [SD], 0.31 [0.06] vs 0.27 ([0.05]; P < 0.001. Conclusions: Se deficiency is very common in Polish patients with MI and HF. Thyroid hormones disturbances were more transient in patients with MI, but more chronic in those with HF