الفهرس 
Introduction & Aim of the workOnly 14 pages are availabe for public view
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Abstract
Despite improvements in the treatment of myocardial infarction (MI), 30% of patients show left ventricular (LV) remodeling post-MI. It is expected that almost 30% of the patients will have an LV ejection fraction (LVEF) below 40% at 6 months post MI. We conducted this study to identify the diagnostic role of micro-ribonucleic acid (miRNA) 208a in acute ST-segment elevation MI (STEMI), and to study the differences in miRNA 208a expression between patients with LV remodeling and those without, as well as its ability to predict the occurrence of major adverse cardiovascular events (MACE), following primary or rescue percutaneous coronary intervention (PCI) for acute STEMI. The aim of this study was to find if miRNA 208 can be used as a marker for early detection of MI, its correlation with cardiac high sensitive troponin and if it has a prognostic role in early detection of patients with LV remodeling or not.
A total of 100 AMI patients were enrolled for the study. The gender ratio was 85:15 (male: female). Another 50 healthy volunteers were recruited to provide a direct comparison of miRNA levels with AMI patients.
Patients with cardiomyopathies, congenital heart disease, atrial fibrillation, and severe valvular diseases, Patients planning for CABG, and patients with severe chronic systemic diseases, such as: chronic kidney disease, hepatic impairment, cancer were excluded.
Relative expression of miRNA 208a level was significantly higher in patients with AMI (165.91±17.57) than healthy controls (14.38±2.17), p <0.001 with cutoff value of 77 for miRNA 208a expression, is 100% sensitive and specific for the diagnosis of acute STEMI. Our results showed strong positive correlation between miRNA 208a expression and cardiac troponins; r: 0.886. At follow-up, 39 patients (39%) were classified as having LV remodeling. miRNA 208a level was significantly higher in patients with LV remodeling (170.05±16.61) than in patients without LV remodeling (159.91±15.25), p-value 0.003.
miRNA 208a was significantly higher in patients who died than those who survived, p <0.001, in patients with early complications than those without, p <0.001, and in those with late complications than those without p 0.001. miRNA 208a has 64.1% sensitivity and 63% specificity for the prediction of LV remodeling with a cut-off value of 162.5, p value 0.002 and AUC 0.692. miRNA 208a level, LVEDV, and E.F showed that the most powerful factor that can predict LV remodeling was miRNA 208a level (R¬2= 1.08), p value 0.002.
31 patients (31%) in group I developed MACE (death, cardiogenic shock, heart failure, or readmission for acute coronary syndrome). that miRNA was an independent predictor of MACE; OR 1.12, p value < 0.001. miRNA 208a has 87.1 % sensitivity and 85.5% specificity for the prediction of MACE with a cut-off value of >171, p value <0.001 and AUC 0.884.
In patients with LV remodeling; the LV ejection fraction (LVE.F) was significantly lower, while the LV end diastolic volume (EDV) and the LV end systolic volume (ESV) were significantly higher at six months follow-up compared to the time of admission. On the other hand, the GLS was impaired all through after MI in those patients, with no significant difference between the 6 months follow-up and the admission measures may be due to the ability of GLS to detect early loss of myocardial contractility.
In patients without LV remodeling; the LVEF, EDV, and LVESV were statistically similar at six months and at admission, while the GLS was significantly better at 6 months than at admission may be due to improvement of myocardial stunning. Among echocardiographic parameters E.F, LVESV, presence of moderate MR and GLS all are independent predictors of MACE.
Conclusion
miRNA 208a is a good biomarker for MI, as it is early expressed in the serum of STEMI patients from the 1st hour after chest pain. miRNA-208a level in plasma is not known to increase in response to cardiac hypertrophy, or other causes of troponin elevation, which may give miRNA 208a a priority in the diagnosis of acute MI.
miRNA 208a was also found to be a good predictor of LV remodeling and of MACE during a 6-month follow-up period after STEMI.
Reduced systolic global longitudinal strain was found to have an important impact on LV remodeling & MACE following AMI and has a potential for patient risk stratification in the acute phase of MI.
Limitations
The main limitation of our study was a relatively small sample size, so our results need to be confirmed by a larger scale study. Some bias in strain evaluation because of image quality inaccuracy may be present. Every effort, however, was done to obtain high quality echocardiographic images.
Recommendations
1- Large scale study is recommended in patients with STEMI and NSTEMI to compare the pattern of expression of miRNA in each group.
2- Follow up of level of miRNA after 6 months to show the level of expression in long term follow up in patient with myocardial remodeling.
3- Use of GLS which may be better than EF for early risk stratification of patients with STEMI.