Impact of Intramyocardial Hemorrhage on Clinical Outcomes in ST-Elevation Myocardial Infarction: A Systematic Review and Meta-analysis

Dissolving porcine and human microthrombi by short exposure to microdoses of alteplase in an in vitro model of microvascular obstruction

Coronary microvascular obstruction (MVO) occurs in up to 57% of patients suffering from ST-segment elevation myocardial infarction (STEMI). One cause for MVO is distal embolization by microthrombi after percutaneous coronary intervention (PCI) of the infarct-related coronary artery. MVO is associated with an adverse cardiac prognosis post-STEMI. However, there are no evidence-based therapies for MVO, presenting an unmet therapeutic need. We investigated a novel pharmacotherapeutic approach to resolve embolizing MVO using an in vitro microfluidic model with porcine or human microthrombi to investigate thrombolysis with alteplase, a fibrinolytic drug. We show that a brief (90 s) exposure to concentrated microdoses of alteplase significantly reduces microthrombus size by up to 75%. 50% lysis occurred within six to twelve minutes after alteplase exposure depending on the initial microdose. Our results suggest that delivering a therapeutic drug directly to the microvasculature to briefly achieve high local drug concentrations has the potential to address embolizing MVO. The combination of short drug exposure and high local concentration is possible with a recently developed infusion system based on intracoronary controlled flow infusion (CoFI). CoFI uses microdoses of alteplase that are up to 1300 times lower than intravenous doses and could thereby minimize bleeding risk.

Addition of eptifibatide and manual thrombus aspiration to ticagrelor does not improve long-term survival after STEMI treated with primary PCI

Background: Current guidelines recommend that glycoprotein IIb/IIIa inhibitor (GPI) and manual aspiration thrombectomy should not be routinely used in patients with ST-segment elevation myocardial infarction (STEMI) treated by primary percutaneous coronary intervention (pPCI), although there is a lack of dedicated studies. The aim of this study was to examine the impact of combined usage of a potent P2Y12 inhibitor, GPI, and manual aspiration thrombectomy on long-term survival after STEMI. Methods: All STEMI patients treated by pPCI in a tertiary center who have been included prospectively in the local PCI registry between January 2016 and December 2022 were analyzed in this study. Patients were excluded if they required oral anticoagulation or bridging between clopidogrel or ticagrelor during hospitalization. Results: A total of 1,210 patients were included in the present study, with a median follow-up of 2.78 (1.00-4.88) years. Ticagrelor significantly reduced all-cause and cardiovascular-cause mortality [HR = 0.27 (0.21-0.34), p < 0.0001 and HR = 0.23 (0.17-0.30), p < 0.0001, respectively]. Eptifibatide significantly reduced all-cause and cardiovascular-cause mortality [HR = 0.72 (0.57-0.92), p = 0.002, and HR = 0.68 (0.52-0.89), p = 0.001, respectively]. Manual thrombus aspiration had no significant effect on both all-cause and cardiovascular-cause mortality. In multivariate Cox regression, all-cause mortality was reduced by ticagrelor, while eptifibatide or manual thrombus aspiration had no significant effect. However, cardiovascular-cause mortality was reduced by both ticagrelor and eptifibatide, while manual thrombus aspiration had no significant effect. Conclusion: Ticagrelor consistently reduced cardiovascular and all-cause mortality, while eptifibatide reduced only cardiovascular mortality. Manual thrombus aspiration provided no long-term benefit. Our findings support the current guideline recommendation that GPI and manual aspiration thrombectomy should not be routinely used in treatment of STEMI with pPCI.

Cardiac Magnetic Resonance Imaging Based Ischemic Injury Pattern in Patients with Acute Myocardial Infarction Sensu Left Ventricular Global Systolic Function

The purpose of the study was to identify factors characterizing a decrease in LV global systolic function in patients with ST-segment elevation myocardial infarction (STEMI) after revascularization using cardiac magnetic resonance imaging (MRI)-based ischemic injury pattern and laboratory parameters sensu left ventricular global systolic function. A total of 109 STEMI patients were examined. The patients underwent contrast-enhanced cardiac MRI with a 1.5 Tesla GE SIGNA Voyager (GE HealthCare, Chicago, IL, USA) on the 7th-10th days from the onset of the disease. According to cardiac MRI analysis, the patients were divided into the following groups with regard to left ventricular ejection fraction (LVEF) values: Group 1-patients with LVEF ≥ 50%; group 2-patients with mildly reduced LVEF 40-49%; group 3-patients with low LVEF < 40%. A predominance of most parameters of the ischemic injury pattern was noted in patients with mildly reduced and low LVEF versus patient group with LVEF ≥ 50%. Some risk factors for a decrease in LVEF < 50% systolic function in STEMI patients after revascularization were revealed: male gender; time from the onset of the anginal attack to revascularization; coronary artery status; several LV parameters; ischemic injury characteristics; natriuretic peptide and troponin I levels.

Temporal Trends in Infarct Severity Outcomes in ST-Segment-Elevation Myocardial Infarction: A Cardiac Magnetic Resonance Imaging Study

Background Severity of myocardial tissue injury is a main determinant of morbidity and death related to ST-segment-elevation myocardial infarction (STEMI). Temporal trends of infarct characteristics at the myocardial tissue level have not been described. This study sought to assess temporal trends in infarct characteristics through a comprehensive assessment by cardiac magnetic resonance imaging at a standardized time point early after STEMI. Methods and Results We analyzed patients with STEMI treated with percutaneous coronary intervention at the University Hospital of Innsbruck who underwent cardiac magnetic resonance imaging between 2005 and 2021. The study period was divided into terciles. Myocardial damage characteristics were assessed using a multiparametric cardiac magnetic resonance imaging protocol within the first week after STEMI and compared between groups. A total of 843 patients with STEMI (17% women) with a median age of 57 (interquartile range, 51-66) years were analyzed. While age, sex, and the clinical risk profile expressed as thrombolysis in myocardial infarction risk score were comparable across the study period, there were differences in guideline-recommended therapies. At the same time, there was no significant change in infarct size (P=0.25), microvascular obstruction (P=0.50), and intramyocardial hemorrhage (P=0.34). Left ventricular remodeling indices and left ventricular ejection fraction remained virtually unchanged (all P>0.05). Major adverse cardiovascular events at 4 (interquartile range, 4-5) months were similar between groups (P=0.36). Conclusions In this magnetic resonance imaging study investigating patients with STEMI treated with primary percutaneous coronary intervention over the past 15 years, no change in infarct severity at the myocardial level has been observed. Clinical research on novel therapeutic approaches to reduce myocardial tissue injury should be a priority.