Fatal myocardial rupture after acute myocardial infarction complicated by heart failure, left ventricular dysfunction, or both: the VALsartan In Acute myocardial iNfarcTion Trial (VALIANT)

Echocardiographic features of myocardial rupture after acute myocardial infarction on emergency echocardiography

OBJECTIVE

Myocardial rupture is a fatal complication of acute myocardial infarction (AMI). Early diagnosis of myocardial rupture is feasible when emergency physicians (EPs) perform emergency transthoracic echocardiography (TTE). The purpose of this study was to report the echocardiographic features of myocardial rupture on emergency TTE performed by EPs in the emergency department (ED).

METHODS

This was a retrospective and observational study involving consecutive adult patients presenting with AMI who underwent TTE performed by EPs in the ED of a single academic medical center from March 2008 to December 2019.

RESULTS

Fifteen patients with myocardial rupture, including eight (53.3%) with free wall rupture (FWR), five (33.3%) with ventricular septal rupture (VSR), and two (13.3%) with FWR and VSR, were identified. Fourteen of the 15 patients (93.3%) were diagnosed on TTE performed by EPs. Diagnostic echocardiographic features were found in 100% of the patients with myocardial rupture, including pericardial effusion for FWR and a visible shunt on the interventricular septum for VSR. Additional echocardiographic features indicating myocardial rupture were thinning or aneurysmal dilatation in 10 patients (66.7%), undermined myocardium in six patients (40.0%), abnormal regional motions in six patients (40.0%), and pericardial hematoma in six patients (40.0%).

CONCLUSION

Early diagnosis of myocardial rupture after AMI is possible using echocardiographic features on emergency TTE performed by EPs.

2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The guideline for coronary artery revascularization replaces the 2011 coronary artery bypass graft surgery and the 2011 and 2015 percutaneous coronary intervention guidelines, providing a patient-centric approach to guide clinicians in the treatment of patients with significant coronary artery disease undergoing coronary revascularization as well as the supporting documentation to encourage their use.

METHODS

A comprehensive literature search was conducted from May 2019 to September 2019, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, CINHL Complete, and other relevant databases. Additional relevant studies, published through May 2021, were also considered. Structure: Coronary artery disease remains a leading cause of morbidity and mortality globally. Coronary revascularization is an important therapeutic option when managing patients with coronary artery disease. The 2021 coronary artery revascularization guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with coronary artery disease who are being considered for coronary revascularization, with the intent to improve quality of care and align with patients' interests.

2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The guideline for coronary artery revascularization replaces the 2011 coronary artery bypass graft surgery and the 2011 and 2015 percutaneous coronary intervention guidelines, providing a patient-centric approach to guide clinicians in the treatment of patients with significant coronary artery disease undergoing coronary revascularization as well as the supporting documentation to encourage their use.

METHODS

A comprehensive literature search was conducted from May 2019 to September 2019, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, CINHL Complete, and other relevant databases. Additional relevant studies, published through May 2021, were also considered.

STRUCTURE

Coronary artery disease remains a leading cause of morbidity and mortality globally. Coronary revascularization is an important therapeutic option when managing patients with coronary artery disease. The 2021 coronary artery revascularization guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with coronary artery disease who are being considered for coronary revascularization, with the intent to improve quality of care and align with patients' interests.

Lgr4 Governs a Pro-Inflammatory Program in Macrophages to Antagonize Post-Infarction Cardiac Repair

RATIONALE

Macrophages are critically involved in wound healing following myocardial infarction (MI). Lgr4, a member of LGR (leucine-rich repeat-containing G protein-coupled receptor) family, is emerging as a regulator of macrophage-associated immune responses. However, the contribution of Lgr4 to macrophage phenotype and function in the context of MI remains unclear.

OBJECTIVE

To determine the role of macrophage Lgr4 in MI and to dissect the underlying mechanisms.

METHODS AND RESULTS

During early inflammatory phase of MI, infarct macrophages rather than neutrophils expressed high level of Lgr4. Macrophage-specific Lgr4 knockout mice had no baseline cardiovascular defects but manifested improved heart function, modestly reduced infarct size, decreased early mortality due to cardiac rupture, and ameliorated adverse remodeling after MI. Improved outcomes in macrophage-specific Lgr4 knockout mice subjected to MI were associated with mitigated ischemic injury and optimal infarct healing, as determined by reduction of cardiac apoptosis in the peri-infarct zone, attenuation of local myocardial inflammatory response, decrease of matrix metalloproteinase expression in the infarct, enhancement of angiogenesis, myofibroblast proliferation, and collagen I deposition in reparative granulation tissue as well as formation of collagen-rich scar. More importantly, macrophage-specific Lgr4 knockout infarcts had reduced numbers of infiltrating leukocytes and inflammatory macrophages but harbored abundant reparative macrophage subsets. Lgr4-null infarct macrophages exhibited a less inflammatory transcriptional signature. These findings were further supported by transcriptomic profiling data showing repression of multiple pathways and broad-spectrum genes associated with proinflammatory responses in macrophage-specific Lgr4 knockout infarcts. Notably, we discovered that Lgr4-mediated functional phenotype programing in infarct macrophages was at least partly attributed to regulation of AP (activator protein)-1 activity. We further demonstrated that the synergistic effects of Lgr4 on AP-1 activation in inflammatory macrophages occurred via enhancing CREB (cAMP response element-binding protein)-mediated c-Fos, Fosl1, and Fosb transactivation.

CONCLUSIONS

Together, our data highlight the significance of Lgr4 in governing proinflammatory phenotype of infarct macrophages and postinfarction repair.

Post-infarction left ventricular free wall rupture: 12-years experience from the Cardiac Centre of the Institute of Clinical and Experimental Medicine in Prague, Czech Republic

BACKGROUND

Post-infarction left ventricular free wall rupture (LVFWR) is a feared and catastrophic complication of myocardial infarction that carries a high surgical and hospital mortality. Due to the rarity of this complication, little information exists on surgical treatment and outcomes. Goal and Methods. The goal of this study was to present our experience with LVFWR. We present a retrospective cohort of 19 consecutive patients who were surgically treated in the Cardiac Centre of the Institute of Clinical and Experimental Medicine in Prague between January 2006 and December 2017.

RESULTS

Thirty-day mortality was 26%. Five patients died. Four patients died in the operating theatre and one patient on the ninth postoperative day following re-rupture. Seventy-four percent of the patient cohort survived and were discharged from hospital. The median length of follow-up was 45 months (range 0.75-150). No patient died during follow-up. Median postoperative ejection fraction was 45% (range 25-65%). Angina pectoris and dyspnea were investigated during follow-up and graded according to the Canadian cardiology society (CCS) and the New York Heart Association (NYHA) classifications. Fourteen patients had CCS class I, eight patients had NYHA class I dyspnea and six patients had NYHA class II. Re-rupture occurred after hospital discharge in one patient one month after the original surgery. The patient was treated successfully by urgent surgical intervention.

CONCLUSION

LVFWR is a catastrophic and challenging complication of myocardial infarction. Good outcomes can be achieved by rapid diagnosis and urgent surgical intervention as shown by our results.

Pharmacological interventions for heart failure in people with chronic kidney disease

BACKGROUND

Approximately half of people with heart failure have chronic kidney disease (CKD). Pharmacological interventions for heart failure in people with CKD have the potential to reduce death (any cause) or hospitalisations for decompensated heart failure. However, these interventions are of uncertain benefit and may increase the risk of harm, such as hypotension and electrolyte abnormalities, in those with CKD.

OBJECTIVES

This review aims to look at the benefits and harms of pharmacological interventions for HF (i.e., antihypertensive agents, inotropes, and agents that may improve the heart performance indirectly) in people with HF and CKD.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies through 12 September 2019 in consultation with an Information Specialist and using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

We included randomised controlled trials of any pharmacological intervention for acute or chronic heart failure, among people of any age with chronic kidney disease of at least three months duration.

DATA COLLECTION AND ANALYSIS

Two authors independently screened the records to identify eligible studies and extracted data on the following dichotomous outcomes: death, hospitalisations, worsening heart failure, worsening kidney function, hyperkalaemia, and hypotension. We used random effects meta-analysis to estimate treatment effects, which we expressed as a risk ratio (RR) with 95% confidence intervals (CI). We assessed the risk of bias using the Cochrane tool. We applied the GRADE methodology to rate the certainty of evidence.

MAIN RESULTS

One hundred and twelve studies met our selection criteria: 15 were studies of adults with CKD; 16 studies were conducted in the general population but provided subgroup data for people with CKD; and 81 studies included individuals with CKD, however, data for this subgroup were not provided. The risk of bias in all 112 studies was frequently high or unclear. Of the 31 studies (23,762 participants) with data on CKD patients, follow-up ranged from three months to five years, and study size ranged from 16 to 2916 participants. In total, 26 studies (19,612 participants) reported disaggregated and extractable data on at least one outcome of interest for our review and were included in our meta-analyses. In acute heart failure, the effects of adenosine A1-receptor antagonists, dopamine, nesiritide, or serelaxin on death, hospitalisations, worsening heart failure or kidney function, hyperkalaemia, hypotension or quality of life were uncertain due to sparse data or were not reported. In chronic heart failure, the effects of angiotensin-converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB) (4 studies, 5003 participants: RR 0.85, 95% CI 0.70 to 1.02; I² = 78%; low certainty evidence), aldosterone antagonists (2 studies, 34 participants: RR 0.61 95% CI 0.06 to 6.59; very low certainty evidence), and vasopressin receptor antagonists (RR 1.26, 95% CI 0.55 to 2.89; 2 studies, 1840 participants; low certainty evidence) on death (any cause) were uncertain. Treatment with beta-blockers may reduce the risk of death (any cause) (4 studies, 3136 participants: RR 0.69, 95% CI 0.60 to 0.79; I² = 0%; moderate certainty evidence). Treatment with ACEi or ARB (2 studies, 1368 participants: RR 0.90, 95% CI 0.43 to 1.90; I² = 97%; very low certainty evidence) had uncertain effects on hospitalisation for heart failure, as treatment estimates were consistent with either benefit or harm. Treatment with beta-blockers may decrease hospitalisation for heart failure (3 studies, 2287 participants: RR 0.67, 95% CI 0.43 to 1.05; I² = 87%; low certainty evidence). Aldosterone antagonists may increase the risk of hyperkalaemia compared to placebo or no treatment (3 studies, 826 participants: RR 2.91, 95% CI 2.03 to 4.17; I² = 0%; low certainty evidence). Renin inhibitors had uncertain risks of hyperkalaemia (2 studies, 142 participants: RR 0.86, 95% CI 0.49 to 1.49; I² = 0%; very low certainty). We were unable to estimate whether treatment with sinus node inhibitors affects the risk of hyperkalaemia, as there were few studies and meta-analysis was not possible. Hyperkalaemia was not reported for the CKD subgroup in studies investigating other therapies. The effects of ACEi or ARB, or aldosterone antagonists on worsening heart failure or kidney function, hypotension, or quality of life were uncertain due to sparse data or were not reported. Effects of anti-arrhythmic agents, digoxin, phosphodiesterase inhibitors, renin inhibitors, sinus node inhibitors, vasodilators, and vasopressin receptor antagonists were very uncertain due to the paucity of studies.

AUTHORS' CONCLUSIONS

The effects of pharmacological interventions for heart failure in people with CKD are uncertain and there is insufficient evidence to inform clinical practice. Study data for treatment outcomes in patients with heart failure and CKD are sparse despite the potential impact of kidney impairment on the benefits and harms of treatment. Future research aimed at analysing existing data in general population HF studies to explore the effect in subgroups of patients with CKD, considering stage of disease, may yield valuable insights for the management of people with HF and CKD.

N-acetyl-seryl-aspartyl-lysyl-proline treatment protects heart against excessive myocardial injury and heart failure in mice

Myocardial infarction (MI) in mice results in cardiac rupture at 4-7 days after MI, whereas cardiac fibrosis and dysfunction occur later. N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) has anti-inflammatory, anti-fibrotic, and pro-angiogenic properties. We hypothesized that Ac-SDKP reduces cardiac rupture and adverse cardiac remodeling, and improves function by promoting angiogenesis and inhibiting detrimental reactive fibrosis and inflammation after MI. C57BL/6J mice were subjected to MI and treated with Ac-SDKP (1.6 mg/kg per day) for 1 or 5 weeks. We analyzed (1) intercellular adhesion molecule-1 (ICAM-1) expression; (2) inflammatory cell infiltration and angiogenesis; (3) gelatinolytic activity; (4) incidence of cardiac rupture; (5) p53, the endoplasmic reticulum stress marker CCAAT/enhancer binding protein homology protein (CHOP), and cardiomyocyte apoptosis; (6) sarcoplasmic reticulum Ca2+ ATPase (SERCA2) expression; (7) interstitial collagen fraction and capillary density; and (8) cardiac remodeling and function. Acutely, Ac-SDKP reduced cardiac rupture, decreased ICAM-1 expression and the number of infiltrating macrophages, decreased gelatinolytic activity, p53 expression, and myocyte apoptosis, but increased capillary density in the infarction border. Chronically, Ac-SDKP improved cardiac structures and function, reduced CHOP expression and interstitial collagen fraction, and preserved myocardium SERCA2 expression. Thus, Ac-SDKP decreased cardiac rupture, ameliorated adverse cardiac remodeling, and improved cardiac function after MI, likely through preserved SERCA2 expression and inhibition of endoplasmic reticulum stress.

Endogenous muscle atrophy F-box is involved in the development of cardiac rupture after myocardial infarction

Muscle atrophy F-box (MAFbx/atrogin-1), an E3 ubiquitin ligase, is a crucial mediator of skeletal muscle atrophy and cardiac hypertrophy in response to pressure overload and exercise. The role of MAFbx in the regulation of cardiac remodeling after myocardial infarction (MI) remains unclear. Permanent coronary ligation of the left coronary artery was performed on MAFbx knockout (KO) and wild-type (WT) mice and MAFbx expression in the WT mice was shown to be significantly increased in the left ventricles after MI. The mortality rate due to post-MI cardiac rupture was significantly decreased in MAFbx KO mice compared to that in the WT mice. DNA microarray and mRNA expression analyses revealed that the upregulation of genes involved in inflammatory processes and cell motility of leukocytes and neutrophils, including Mmp9, Il1b, Cxcl2, and Nlrp3, was significantly attenuated in MAFbx KO mice 1 day after MI. MAFbx downregulation inhibited nuclear factor-κB (Nfkb) activation after MI. Flow cytometry results demonstrated that the myocardial infiltration of neutrophils was suppressed in MAFbx KO mice 1 day after MI. Nlrp3 and Il1b protein levels were decreased in MAFbx KO mice compared with those in the WT mice. MAFbx downregulation significantly attenuated Tnfa-induced Cxcl2, Il1b, and Nlrp3 expression in cardiomyocytes. We conclude that MAFbx plays an important role in the mediation of excessive inflammation, including neutrophil infiltration, inflammasome formation, and production of proinflammatory cytokines through the activation of Nfkb, promoting cardiac rupture after MI.

Metformin Increases Cardiac Rupture After Myocardial Infarction via the AMPK-MTOR/PGC-1α Signaling Pathway in Rats with Acute Myocardial Infarction

Background

Cardiac rupture often occurs after acute myocardial infarction due to complex and unclear pathogenesis. This study investigated whether metformin increases the incidence of cardiac rupture after myocardial infarction through the AMPK-MTOR/PGC-1α signaling pathway.

Material/Methods

An acute myocardial infarction (MI) mouse model was established. A series of experiments involving RT-qPCR, Western blot, TUNEL staining, and Masson staining were performed in this study.

Results

Myocardial infarction occurred, resulting in the cardiac rupture, and the expression level of PGC-1α increased in the cardiac myocardium. Meanwhile, the proportion of myocardial NT-PGC-1α/PGC-1α decreased. The expression level of myocardial PGC-1α in MI mice with cardiac rupture after MI was significantly higher than that in the mice without cardiac rupture, and the ratio of myocardial NT-PGC-1α/PGC-1α was low. In addition, increasing the dose of metformin significantly increased the incidence of cardiac rupture after myocardial infarction in MI mice. High-dose metformin caused cardiac rupture in MI mice. Moreover, high-dose metformin (Met 2.0 nM) reduces the proportion of NT-PGC-1α/PGC-1α in primary cardiomyocytes of SD mice (SD-NRVCs [Neonatal rat ventricular cardiomyocytes]), and its effect was inhibited by Compound C (AMPK inhibitor). Further, after 3 days of treatment with high-dose metformin in MI mice, myocardial fibrin synthesis decreased and fibrosis was significantly inhibited. Meanwhile, cardiomyocyte apoptosis increased significantly. With the increase in metformin concentration, the expression level of myocardial LC3b gradually increased in MI mice, suggesting that metformin enhances the autophagy of cardiomyocytes.

Conclusions

These results suggest that metformin increases cardiac rupture after myocardial infarction through the AMPK-MTOR/PGC-1α signaling pathway.

The representation of postinfarction myocardial rupture

The article presents a literature review of the modern conception of postinfarction rupture of the myocardium and predictors of its development.

Association of the SYNTAX Score II with cardiac rupture in patients with ST-segment elevation myocardial infarction undergoing a primary percutaneous coronary intervention

BACKGROUND

Despite advances in reperfusion strategies, medical therapy, and emergent surgery, cardiac rupture (CR) is still a major lethal complication. Numerous parameters have been found to be associated with CR development after a primary percutaneous coronary intervention (pPCI). SYNTAX Score (SS) and SYNTAX Score II (SSII) have been studied in ST-segment elevation myocardial infarction (STEMI) patients, and higher scores have been associated with higher mortality. However, the relationship between CR and SSII is unclear. This study investigates the possible relationship between CR and SS, SSII in STEMI patients treated with pPCI.

PATIENTS AND METHODS

We enrolled 1663 consecutive STEMI patients treated with pPCI, who were divided into two groups according to CR development and compared with each other. Patients were further stratified into the three groups according to their SSII values.

RESULTS

In this study, 33 (1.98%) patients developed CR. Both SS and SSII of those with CR were significantly higher than those without (19.27±4.0 vs. 16.40±4.55; P<0.001 and 49.40±16.54 vs. 30.92±11.80; P<0.001, respectively). It was also observed that CR increased gradually according to increasing SSII tertiles. SSII was found to be an independent predictor for CR (odds ratio=1.043, 95% confidence interval: 1.012-1.074; P=0.006). In the long-term follow-up, all-cause mortality was significantly higher in patients with CR than those without (60.6 vs. 8.8%; P<0.001).

CONCLUSION

This study shows that SSII is an independent predictor for CR. Furthermore, patients with CR were associated with a poor prognosis. Closer follow-up of patients with high SSII may be useful in the early detection and treatment of this fatal complication.

Optical metrics of the extracellular matrix predict compositional and mechanical changes after myocardial infarction

Understanding the organization and mechanical function of the extracellular matrix (ECM) is critical for the development of therapeutic strategies that regulate wound healing following disease or injury. However, these relationships are challenging to elucidate during remodeling following myocardial infarction (MI) due to rapid changes in cellularity and an inability to characterize both ECM microstructure and function non-destructively. In this study, we overcome those challenges through whole organ decellularization and non-linear optical microscopy to directly relate the microstructure and mechanical properties of myocardial ECM. We non-destructively quantify collagen organization, content, and cross-linking within decellularized healthy and infarcted myocardium using second harmonic generation (SHG) and two photon excited autofluorescence. Tensile mechanical testing and compositional analysis reveal that the cumulative SHG intensity within each image volume and the average collagen autofluorescence are significantly correlated with collagen content and elastic modulus of the ECM, respectively. Compared to healthy ECM, infarcted tissues demonstrate a significant increase in collagen content and fiber alignment, and a decrease in cross-linking and elastic modulus. These findings indicate that cross-linking plays a key role in stiffness at the collagen fiber level following infarction, and highlight how this non-destructive approach to assessing remodeling can be used to understand ECM structure-function relationships.

Pharmacological interventions into the renin-angiotensin system with ACE inhibitors and angiotensin II receptor antagonists: effects beyond blood pressure lowering

Hypertension is recognized as an important risk factor for cardiovascular morbidity and mortality. Lowering of blood pressure has been shown to minimize the risk of cardiovascular events, with the majority of antihypertensives demonstrating a similar ability to reduce coronary events and stroke for a given reduction in blood pressure. Agents that modify the activity of the renin-angiotensin system (RAS) have been proposed to exhibit additional effects that might go beyond simple blood pressure lowering. The RAS is a crucial system that regulates extracellular fluid volume and blood pressure. Proposed potential benefits of RAS blockade that go beyond blood pressure lowering include a reduction in platelet aggregation and thrombosis, blunting of cardiac and vascular remodeling, favorable metabolic effects and reno- and cerebro-protection. However, factors such as treatment adherence, duration of action of antihypertensive agents and differences in effects on central versus brachial blood pressure may also result in apparent differences in efficacy of different antihypertensives. The aim of this review article is to examine the available data from clinical studies of antihypertensive drugs for evidence of effects that might legitimately be claimed to go beyond simple blood pressure lowering.

Acute Complications of Myocardial Infarction in the Current Era: Diagnosis and Management

Coronary heart disease is a major cause of mortality and morbidity worldwide. The incidence of mechanical complications of acute myocardial infarction (AMI) has gone down to less than 1% since the advent of percutaneous coronary intervention, but although mortality resulting from AMI has gone down in recent years, the burden remains high. Mechanical complications of AMI include cardiogenic shock, free wall rupture, ventricular septal rupture, acute mitral regurgitation, and right ventricular infarction. Detailed knowledge of the complications and their risk factors can help clinicians in making an early diagnosis. Prompt diagnosis with appropriate medical therapy and timely surgical intervention are necessary for favorable outcomes.

Predictive factors of cardiac rupture in patients with ST-elevation myocardial infarction

Cardiac rupture (CR) is a potentially fatal mechanical complication of ST-elevation myocardial infarction (STEMI). We aimed to determine the incidence and risk factors of CR in Chinese STEMI patients. A total of 9798 consecutive STEMI patients from four centers in China were retrospectively analyzed, among which 178 patients had CR. STEMI patients without CR were chosen as a control group. Clinical characteristics were compared between STEMI patients with CR and those without CR. The incidence of CR in STEMI patients was 1.82%, and the 30-d mortality was up to 61.2%. CR patients were significantly older, more female, and associated with a longer time from onset of pain to hospital admission than their non-CR counterparts (P<0.001). More patients with anterior myocardial infarction (82.1%) were found in the CR group, and CR patients had significantly higher heart rates than the control group ((91±19) bpm vs. (71±16) bpm; P<0.001). In multiple-adjusted models, the independent risk factors of CR were advanced age, female gender, anaemia, increased heart rate, anterior myocardial infarction, increased white blood cell (WBC) count, delayed admission, and renal dysfunction. The level of hemoglobin remained a significant determinant factor of CR (OR (95% CI): 0.82 (0.75-0.89); P<0.001) after adjusting for various potential confounding factors. Counts of WBC also remained a significant determinant of the CR (OR (95% CI): 1.08 (1.04-1.12); P<0.001). A number of variables were independently related to CR. This study indicated, for the first time, that both hemoglobin and WBC levels were independently correlated with occurrence of CR.

Olmesartan prevents cardiac rupture in mice with myocardial infarction by modulating growth differentiation factor 15 and p53

BACKGROUND AND PURPOSE

Cardiac rupture is a catastrophic complication that occurs after acute myocardial infarction (MI) and, at present, there are no effective pharmacological strategies for preventing this condition. Here we investigated the effect of the angiotensin II receptor blocker olmesartan (Olm) on post-infarct cardiac rupture and its underlying mechanisms of action.

EXPERIMENTAL APPROACH

C57Bl/6 mice with MI were treated with Olm, aldosterone (Aldo) or vehicle. Cultured neonatal cardiomyocytes and fibroblasts were exposed to normoxia or anoxia and treated with angiotensin II (Ang II), RNH6270 (active ingredient of Olm) or Aldo.

KEY RESULTS

The mortality rate and incidence of cardiac rupture in MI mice during the first week in the Olm-treated group were significantly lower than in the vehicle-treated group. Olm or RNH6270 reduced myeloperoxidase staining in the infarcted myocardium, decreased apoptosis in cultured cardiomyocytes and fibroblasts, as assessed by Hoechst staining and TUNEL assay, attenuated the accumulation of p53 and phosphorylated p53 and cleaved caspase 3 induced by MI or Ang II, as assessed by Western blotting, and up-regulated growth differentiation factor-15 (GDF-15). In cultured cardiomyocytes and fibroblasts, treatment with Ang II, Aldo or anoxia significantly down-regulated the expression of GDF-15.

CONCLUSIONS AND IMPLICATIONS

Olm prevents cardiac rupture through inhibition of apoptosis and inflammation, which is attributable to the down-regulation of p53 activity and up-regulation of GDF-15. Our findings suggest that early administration of an AT1 receptor anatagonist to patients with acute MI is a potential preventive approach for cardiac rupture.

Thymosin-β4 prevents cardiac rupture and improves cardiac function in mice with myocardial infarction

Thymosin-β4 (Tβ4) promotes cell survival, angiogenesis, and tissue regeneration and reduces inflammation. Cardiac rupture after myocardial infarction (MI) is mainly the consequence of excessive regional inflammation, whereas cardiac dysfunction after MI results from a massive cardiomyocyte loss and cardiac fibrosis. It is possible that Tβ4 reduces the incidence of cardiac rupture post-MI via anti-inflammatory actions and that it decreases adverse cardiac remodeling and improves cardiac function by promoting cardiac cell survival and cardiac repair. C57BL/6 mice were subjected to MI and treated with either vehicle or Tβ4 (1.6 mg·kg(-1)·day(-1) ip via osmotic minipump) for 7 days or 5 wk. Mice were assessed for 1) cardiac remodeling and function by echocardiography; 2) inflammatory cell infiltration, capillary density, myocyte apoptosis, and interstitial collagen fraction histopathologically; 3) gelatinolytic activity by in situ zymography; and 4) expression of ICAM-1 and p53 by immunoblot analysis. Tβ4 reduced cardiac rupture that was associated with a decrease in the numbers of infiltrating inflammatory cells and apoptotic myocytes, a decrease in gelatinolytic activity and ICAM-1 and p53 expression, and an increase in the numbers of CD31-positive cells. Five-week treatment with Tβ4 ameliorated left ventricular dilation, improved cardiac function, markedly reduced interstitial collagen fraction, and increased capillary density. In a murine model of acute MI, Tβ4 not only decreased mortality rate as a result of cardiac rupture but also significantly improved cardiac function after MI. Thus, the use of Tβ4 could be explored as an alternative therapy in preventing cardiac rupture and restoring cardiac function in patients with MI.

Clinical characteristics and short-term outcomes in patients with elevated admission systolic blood pressure after acute ST-elevation myocardial infarction: a population-based study

OBJECTIVE

Prognostic value of lower admission systolic blood pressure (SBP) in patients with acute myocardial infarction has been confirmed, but the impact of elevated admission SBP on short-term outcomes has been evaluated only by a limited number of studies and they have reported conflicting results. The aim of our study was to investigate the characteristics and short-term outcomes in patients with elevated admission SBP after ST-elevation myocardial infarction (STEMI).

DESIGN

A population-based, observational study.

SETTING

The multicentre registry in China.

PARTICIPANTS

A total of 7510 consecutive patients with STEMI were registered. Patients were divided into three groups according to admission SBP: normal admission SBP (100-139 mm Hg), modestly elevated admission SBP (140-179 mm Hg) and excessively elevated admission SBP (≥180 mm Hg). The primary outcomes were 7-day and 30-day all-cause mortality, major adverse cardiac events (MACE) and bleeding rate.

RESULTS

Of 6591 patients, 4182 (63.5%) had normal admission SBP, 2187 (33.2%) modestly elevated admission SBP and 222 (3.4%) excessively elevated admission SBP. Patients with elevated admission SBP had a high-risk profile, such as were more likely to be older, with more concomitant cardiovascular morbidities, presenting with more events of anterior myocardial infarction and less reperfusion treatment. However, 7-day and 30-day all-cause mortality, MACE and bleeding rate were comparable among groups (all p>0.05). Survival curves and MACE curves were similar among groups (p=0.377 and 0.375, respectively). After multivariate adjustment, elevated admission SBP was not associated with increased risk of short-term death and bleeding, and MACE was comparable with normal admission SBP.

CONCLUSIONS

Although those with elevated admission SBP after STEMI were at a higher risk for cardiovascular events, they did not have poorer short-term outcomes compared with patients with normal admission SBP.

Twenty-year route of prevalence of risk factors, treatment patterns, complications, and mortality rate of acute myocardial infarction in Iran

OBJECTIVES

Coronary artery diseases are regarded as the main cause of mortality in most countries. The present study aims at evaluating variations and studying its complications in Iranian patients within past 20 years.

METHODS

This cross-sectional analytical-descriptive study retrospectively evaluated the files of 600 patients with acute myocardial infarction during a 20-year period. Basic data and laboratory information, chemotherapies and intervention treatments of patients were registered in special forms and compared regarding the mentioned time intervals.

RESULTS

There were 440 (73.3%) male and 160 (26.7%) female patients and mean age of the patients was 60.03 ± 11.61 years. Mean duration of hospitalization (p < 0.001) and prevalence of smoking (p < 0.001) had significantly decreased in the past two decades. There was no meaningful difference when considering mortality rate (p = 0.533) and cardiac insufficiency (p = 0.403).

CONCLUSION

The results indicate prominent improvement in the management process of patients suffering from acute myocardial infarction within the past 20 years.

Fatal huge left free wall ventricular rupture after acute posterior myocardial infarction

A 77-year-old man, with a recent history of an acute inferior myocardial infarction, was referred to our hospital with echocardiographic and clinical signs of left ventricular free wall rupture (LVFWR). The intraoperative finding demonstrated a huge double LVFWR. The inferoposterior wall was dramatically destroyed without any possibility to repair.

Postinfarct cardiac free wall rupture detected by multidetector computed tomography

Cardiac free wall rupture after myocardial infarction is one of the life-threatening complications, which often results in sudden onset of cardiogenic shock caused by cardiac tamponade. Multidetector computed tomography (MDCT) provides valuable information in any clinical setting. There have been a few case reports on detecting cardiac rupture by means of CT. We report here a rare case of postinfarct cardiac free wall rupture, whose myocardial tear could be detected by MDCT.