Clinical outcome and correlates of coronary microvascular obstruction in latecomers after acute myocardial infarction

Sphingosine-1-phosphate improves outcome of no-reflow acute myocardial infarction via sphingosine-1-phosphate receptor 1

AIMS

Therapeutic options targeting post-ischaemic cardiac remodelling are sparse. The bioactive sphingolipid sphingosine-1-phosphate (S1P) reduces ischaemia/reperfusion injury. However, its impact on post-ischaemic remodelling independently of its infarct size (IS)-reducing effect is yet unknown and was addressed in this study.

METHODS AND RESULTS

Acute myocardial infarction (AMI) in mice was induced by permanent ligation of the left anterior descending artery (LAD). C57Bl6 were treated with the S1P lyase inhibitor 4-deoxypyridoxine (DOP) starting 7 days prior to AMI to increase endogenous S1P concentrations. Cardiac function and myocardial healing were assessed by cardiovascular magnetic resonance imaging (cMRI), murine echocardiography, histomorphology, and gene expression analysis. DOP effects were investigated in cardiomyocyte-specific S1P receptor 1 deficient (S1PR1 Cardio Cre+) and Cre- control mice and S1P concentrations measured by LC-MS/MS. IS and cardiac function did not differ between control and DOP-treated groups on day one after LAD-ligation despite fourfold increase in plasma S1P. In contrast, cardiac function was clearly improved and myocardial scar size reduced, respectively, on Day 21 in DOP-treated mice. The latter also exhibited smaller cardiomyocyte size and reduced embryonic gene expression. The benefit of DOP treatment was abolished in S1PR1 Cardio Cre+.

CONCLUSIONS

S1P improves cardiac function and myocardial healing post AMI independently of initial infarct size and accomplishes this via the cardiomyocyte S1PR1. Hence, in addition to its beneficial effects on I/R injury, S1PR1 may be a promising target in post-infarction myocardial remodelling as adjunctive therapy to revascularization as well as in patients not eligible for standard interventional procedures.

LncRNA ANRIL knockdown relieves myocardial cell apoptosis in acute myocardial infarction by regulating IL-33/ST2

Objective: To investigate the role of lncRNA ANRIL in the modulation of myocardial cell apoptosis in acute myocardial infarction (AMI).Methods: AMI mice model was established, and lncRNA ANRIL, IL-33 and ST2 expressions were detected by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. The apoptosis of myocardial cells was detected by TUNEL assay. RNA pull-down and RNA immunoprecipitation (RIP) assays were used to confirm the interaction between lncRNA ANRIL and USP17.Results: Compared with sham group, lncRNA ANRIL and ST2 expression levels were up-regulated, and the apoptosis of myocardial cells was increased in heart tissues of AMI group. Compared with normoxia group, the apoptosis of mouse myocardial cell HL-1 and primary murine myocardial cells was increased, and lncRNA ANRIL and ST2 expression levels were up-regulated in hypoxia group. We also found up-regulation of IL-33 in AMI group and hypoxia group. Besides, lncRNA ANRIL affected deubiquitinase USP17-mediated degradation of IL-33. Interfering lncRNA ANRIL reduced the apoptosis of myocardial cells through IL-33/ST2 pathway. In vivo experiments found that interfering lncRNA ANRIL relieved myocardial cell apoptosis and improved heart function in AMI mice.Conclusion: LncRNA ANRIL regulated myocardial cell apoptosis through IL-33/ST2 pathway.

Recurrence of angina after ST-segment elevation myocardial infarction: the role of coronary microvascular obstruction

BACKGROUND

The recurrence of angina after percutaneous coronary intervention affects 20-35% of patients with stable coronary artery disease; however, few data are available in the setting of ST-segment elevation myocardial infarction. We evaluated the relation between coronary microvascular obstruction and the recurrence of angina at follow-up.

METHODS

We prospectively enrolled patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention. Microvascular obstruction was defined as thrombolysis in myocardial infarction flow less than 3 or 3 with myocardial blush grade less than 2. The primary endpoint was the recurrence of angina at follow-up. Moreover, angina status was evaluated by the Seattle angina questionnaire summary score (SAQSS). Therapy at follow-up and the occurrence of major adverse cardiovascular events were also collected.

RESULTS

We enrolled 200 patients. Microvascular obstruction occurred in 52 (26%) of them. Follow-up (mean time 25.17±9.28 months) was performed in all patients. Recurrent angina occurred in 31 (15.5%) patients, with a higher prevalence in patients with microvascular obstruction compared with patients without microvascular obstruction (13 (25.0%) vs. 18 (12.2%), P=0.008). Accordingly, SAQSS was lower and the need for two or more anti-anginal drugs was higher in patients with microvascular obstruction compared with patients without microvascular obstruction. At multiple linear regression analysis a history of previous acute coronary syndrome and the occurrence of microvascular obstruction were the only independent predictors of a worse SAQSS. Finally, the occurrence of major adverse cardiovascular events was higher in patients with microvascular obstruction compared with patients without microvascular obstruction.

CONCLUSIONS

The recurrence of angina in ST-segment elevation myocardial infarction patients treated with primary percutaneous coronary intervention is an important clinical issue. The occurrence of microvascular obstruction portends a worse angina status and is associated with the use of more anti-anginal drugs.

The role of the socio-economic environment on medical outcomes after ST-segment elevation myocardial infarction

Background

According to the World Health Organization, coronary artery disease (CAD), including ST-segment elevation myocardial infarction (STEMI), is the most common cause of death worldwide as well as in Europe and Austria. There is valid data on the impact of conventional risk factors on the medical outcomes for STEMI patients. However, only few studies examine the role of the socio-economic environment for medical outcomes. The main task of this study is to investigate if the socio-economic environment of patients who underwent percutaneous coronary intervention (PCI) after STEMI has an impact on the distribution of risk factors and medical outcomes.

Methods

The study focuses on the population of the City of Vienna, Austria, and includes 870 STEMI patients, who underwent PCI at the General Hospital of Vienna (AKH Wien) between 2008 and 2012. The following data were collected: conventional risk factors (hypertension, hyperlipidemia, diabetes, overweight, smoking, family history and vascular disease) and socio-economic indicators of the patient’s residential district (number of residents, income pre-tax, residents per general practitioner, residents per internal specialist, compulsory education only, academic degree and rate of unemployment). Cox regressions were performed to evaluate the impact of socio-economic environment and conventional risk factors on survival.

Results

Most of the conventional risk factors show a significant difference between deceased and surviving patients. The study revealed significant differences across districts in relation to the socio-economic background of STEMI patients. Surprisingly, medical outcomes, as measured by the survival of patients, are significantly related to a patient’s district of residence (p-Value = 0.028) but not in a systematic way as far as the socio-economic environment of these districts is concerned.

Conclusions

The study provides intuitive evidence for a hitherto understudied Central European context on the link between socio-economic environment and conventional risk factors at population level and the link between conventional risk factors and survival both at the population at the individual level. While this is in line with previous evidence and suggestive of the incorporation of measures of socio-economic status (SES) into policy & guidelines toward the management of CAD, more data on the SES – STEMI nexus are needed at individual level.

Sex-Specific Association Between Coronary Artery Disease Severity and Myocardial Ischemia Induced by Mental Stress

OBJECTIVE

It is unclear whether mental stress-induced myocardial ischemia (MSIMI) is related to obstructive coronary artery disease (CAD). We examined this question and contrasted results with ischemia induced by conventional stress testing (CSIMI). Because women are more susceptible to ischemia without coronary obstruction than men, we examined sex differences.

METHODS

We studied 276 patients 61 years and younger with recent myocardial infarction. CAD severity was quantified using the log-transformed Gensini Score (lnGS) and the Sullivan Stenosis Score. Patients underwent myocardial perfusion imaging with mental stress (public speaking) and conventional (exercise or pharmacological) stress testing. MSIMI and CSIMI were defined as a new or worsening perfusion defect.

RESULTS

The prevalence of MSIMI was 15% in men and 20% in women. The median GS for patients with MSIMI was 65.0 in men and 28.5 in women. In logistic regression models adjusted for demographic and cardiovascular risk factors, CAD severity was associated with CSIMI in the full sample (odds ratio [OR] = 1.49, 95% [CI], 1.14-1.95, per 1-unit increase in lnGS), with no significant difference by sex. Although CAD severity was not associated with MSIMI in the entire sample, results differed by sex. CAD severity was associated with MSIMI among men (OR = 1.95, 95% CI, 1.13-3.36, per 1-unit increase in lnGS), but not among women (OR = 1.02, 95% CI, 0.74-1.42, p = .042 for interaction). Analysis using Sullivan Stenosis Score yielded similar results.

CONCLUSIONS

Findings suggest that CAD severity is related to MSIMI in men but not women. MSIMI in women may therefore be driven by alternative mechanisms such as coronary microvascular disease.

Coronary microembolization and microvascular dysfunction

Plaque erosion, fissuring or rupture occurs spontaneously or during coronary interventions. At some residual blood flow, the atherothrombotic debris is washed into the coronary microcirculation, causing physical obstruction, vasoconstriction, inflammation and ultimately microinfarction. Coronary microembolization also contributes to microvascular obstruction in reperfused acute myocardial infarction. Patients with microvascular obstruction after reperfused myocardial infarction have worse prognosis. Cardioprotective strategies to avoid acute coronary microembolization and rescue myocardium from microvascular obstruction have not yet been established in clinical practice. Subclinical coronary microembolization together with release of thrombogenic, vasoconstrictor and inflammatory substances from a culprit lesion can sensitize the coronary microcirculation and contribute to angina in the absence of major epicardial coronary obstruction. Repetitive coronary microembolization can induce progressive loss of functional cardiomyocytes and induce heart failure in the absence of overt myocardial infarction.