Metoprolol blunts the time-dependent progression of infarct size.

Early metoprolol administration protects against myocardial ischemia-reperfusion injury, but its effect on infarct size progression (ischemic injury) is unknown. Eight groups of pigs (total n = 122) underwent coronary artery occlusion of varying duration (20, 25, 30, 35, 40, 45, 50, or 60 min) followed by reperfusion. In each group, pigs were randomized to i.v. metoprolol (0.75 mg/kg) or vehicle (saline) 20 min after ischemia onset. The primary outcome measure was infarct size (IS) on day7 cardiac magnetic resonance (CMR) normalized to area at risk (AAR, measured by perfusion computed tomography [CT] during ischemia). Metoprolol treatment reduced overall mortality (10% vs 26%, p = 0.03) and the incidence and number of primary ventricular fibrillations during infarct induction. In controls, IS after 20-min ischemia was ≈ 5% of the area AAR. Thereafter, IS progressed exponentially, occupying almost all the AAR after 35 min of ischemia. Metoprolol injection significantly reduced the slope of IS progression (p = 0.004 for final IS). Head-to-head comparison (metoprolol treated vs vehicle treated) showed statistically significant reductions in IS at 30, 35, 40, and 50-min reperfusion. At 60-min reperfusion, IS was 100% of AAR in both groups. Despite more prolonged ischemia, metoprolol-treated pigs reperfused at 50 min had smaller infarcts than control pigs undergoing ischemia for 40 or 45 min and similar-sized infarcts to those undergoing 35-min ischemia. Day-45 LVEF was higher in metoprolol-treated vs vehicle-treated pigs (41.6% vs 36.5%, p = 0.008). In summary, metoprolol administration early during ischemia attenuates IS progression and reduces the incidence of primary ventricular fibrillation. These data identify metoprolol as an intervention ideally suited to the treatment of STEMI patients identified early in the course of infarction and requiring long transport times before primary angioplasty.

[ST elevation myocardial infarction in young adults: Is there an interest for thrombophilia screening?] / Syndrome coronarien aigu avec sus-décalage du segment ST chez les jeunes adultes : le bilan de thrombophilie a-t-il un intérêt ?

BACKGROUND: Coronary lesions characteristics as well as patient thrombogenicity can explain coronary events manifestation. In young patient, local conditions are usually less important and thrombogenicity could play a significant role. Assessing thrombophilia could be justified in young patients and may induce an adapted therapeutic management. PURPOSE: We aimed to assess the prevalence of thrombophilia and therapeutic modification in young adults aged≤55 years admitted in our department for ST elevation myocardial infarction (STEMI). METHODS: From January 2013 to January 2017, data on all patients aged≤55 years with STEMI admitted in emergency were retrospectively retrieved from our database. Thrombophilia investigation was made regarding clinical (with or without cardiovascular risk factors [CVRF]), biological and/or angiographic evaluation. RESULTS: A total of 133 patients aged≤55 years with STEMI were included. Cardiac arrest occurred in 15 patients (11%). One or less CVRF were found in 47 patients (35%). Smoking was reported in 93 patients (70%) and drug addiction (cannabis, cocaine) in 19 patients (14%). A subset of 51 patients (38%) were screened for thrombophilia. Patients with thrombophilia assessment were younger, less active smokers and presented less CVRF than patients without investigation (P<0.001). Single vessel diseased was found in 88 patients (66%). No differences regarding coronary procedural characteristic were found between the two groups. The most frequently encountered aetiology, found in 122 patients (92%), was de novo intra-arterial thrombosis related to atherosclerosis. In patients with thrombophilia assessment (n=51), one or more abnormal biological results was found in 22 patients (43%) and a therapeutic adjustment was made in 6 patients (12%). CONCLUSION: Thrombophilia screening in young STEMI adults showed an abnormality in 43% of cases. Antithrombotic treatment can be modified after its demonstration.

Changes in Coronary Plaque Composition in Patients With Acute Myocardial Infarction Treated With High-Intensity Statin Therapy (IBIS-4): A Serial Optical Coherence Tomography Study.

OBJECTIVES: This study assessed changes in optical coherence tomography (OCT)-defined plaque composition in patients with ST-elevation myocardial infarction (STEMI) receiving high-intensity statin treatment. BACKGROUND: OCT is a high-resolution modality capable of measuring plaque characteristics including fibrous cap thickness (FCT) and macrophage infiltration. There is limited in vivo evidence regarding the effects of statins on OCT-defined coronary atheroma composition and no evidence in the context of STEMI. METHODS: In the IBIS-4 (Integrated Biomarker Imaging Study-4), 103 patients underwent intravascular ultrasonography and OCT of 2 noninfarct-related coronary arteries in the acute phase of STEMI. Patients were treated with high-dose rosuvastatin for 13 months. Serial OCT imaging was available in 153 arteries from 83 patients. We measured FCT by using a semi-automated method. Co-primary endpoints consisted of the change in minimum FCT (measured in fibroatheromas) and change in macrophage line arc. RESULTS: At 13 months, median low-density lipoprotein cholesterol had decreased from 128 mg/dl to 73.6 mg/dl. Minimum FCT, measured in 31 lesions from 27 patients, increased from 64.9 ± 19.9 µm to 87.9 ± 38.1 µm (p = 0.008). Macrophage line arc decreased from 9.6° ± 12.8° to 6.4° ± 9.6° (p < 0.0001). The secondary endpoint, mean lipid arc, decreased from 55.9° ± 37° to 43.5° ± 33.5°. In lesion-level analyses (n = 191), 9 of 13 thin-cap fibroatheromata (TCFAs) at baseline (69.2%) regressed to non-TCFA morphology, whereas 2 of 178 non-TCFA lesions (1.1%) progressed to TCFAs. CONCLUSIONS: In this observational study, we found significant increase in minimum FCT, reduction in macrophage accumulation, and frequent regression of TCFAs to other plaque phenotypes in nonculprit lesions of patients with STEMI treated with high-intensity statin therapy.