Pre-hospital versus in-hospital thrombolysis for ST-elevation myocardial infarction

Nebulized Non-Immunogenic Staphylokinase in the Mice Acute Lung Injury Model

Acute lung injury (ALI) as a model of acute respiratory distress syndrome is characterized by inflammation, complex coagulation, and hematologic abnormalities which result in the formation of fibrin-platelet microthrombi in the pulmonary vessels with the rapid development of progressive respiratory dysfunction. We hypothesize that a nebulized fibrinolytic agent, non-immunogenic staphylokinase (nSta), may be useful for ALI therapy. First, the effect of the nebulized nSta (0.2 mg/kg, 1.0 mg/kg, or 2.0 mg/kg) on the coagulogram parameters was studied in healthy rats. ALI was induced in mice by nebulized administration of lipopolysaccharide (LPS) at a dose of 10 mg/kg. nSta (0.2 mg/kg, 0.4 mg/kg or 0.6 mg/kg) was nebulized 30 min, 24 h, and 48 h after LPS administration. The level of pro-inflammatory cytokines was determined in the blood on the 8th day after LPS and nSta administration. The assessment of lung damage was based on their weighing and microscopic analysis. Fibrin/fibrinogen deposition in the lungs was determined by immunohistochemistry. After nSta nebulization in healthy rats, the fibrinogen blood level as well as activated partial thromboplastin time and prothrombin time did not change. In the nebulized ALI model, the mice showed an increase in lung weight due to their edema and rising fibrin deposition. An imbalance of proinflammatory cytokines was also found. Forty percent of mice with ALI without nSta nebulization had died. Nebulized nSta at a dose of 0.2 mg/kg reduced the severity of ALI: a decrease in interstitial edema and inflammatory infiltration was noted. At a dose of 0.4 mg/kg of nebulized nSta, the animals showed no peribronchial edema and the bronchi had an open clear lumen. At a dose of 0.6 mg/kg of nebulized nSta, the manifestations of ALI were completely eliminated. A significant dose-dependent reduction of the fibrin-positive areas in the lungs of mice with ALI was established. Nebulized nSta had a normalizing effect on the proinflammatory cytokines in blood— interleukin (IL)-1α, IL-17A, IL-6, and granulocyte-macrophage colony-stimulating factor (GM-CSF). These data showed the effectiveness of nebulized nSta and the perspectives of its clinical usage in COVID-19 patients with acute respiratory distress syndrome (ARDS).

Creatine kinase during non-ST-segment elevation acute coronary syndromes is associated with major bleeding

Background

It was recently reported that highly elevated plasma activity of the ADP-scavenging enzyme creatine kinase (CK), to >10 times the upper reference limit (URL), is independently associated with fatal or non-fatal bleeding during treatment for ST-segment elevation myocardial infarction (OR 2.6 (95% CI, 1.8 to 2.7)/log CK increase). Evidence indicates that CK attenuates ADP-dependent platelet aggregation. This study investigates whether moderately elevated CK in non-ST-segment elevation acute coronary syndrome (NSTE-ACS) is associated with major bleeding.

Methods

The Thrombolysis In Myocardial Ischemia (TIMI) 3B trial compared recombinant tissue-type plasminogen activator (rt-PA) (35–80 mg) with placebo and early catheterisation with conservative management in patients with NSTE-ACS. Main outcomes of the current study are the independent association of peak plasma CK (CKmax) with adjudicated fatal or non-fatal major bleeding (primary) and with combined major bleeding, stroke and hospital death (secondary), with covariables including age, sex, body mass index, systolic blood pressure, creatinine and assignment to add-on rt-PA versus placebo. Discrimination was assessed with C-statistics.

Results

The study included 1473 patients (66% men, 80% white, mean age 59 years, SE 0.3). CKmax ranged between 15 and 19 045 IU/L (mean (SE), 450 (24) IU/L; two times URL). Major bleeding occurred in 2.0% (mean age 65 (1.3) years; mean CKmax 1015 (319) IU/L; six times URL), and the combined outcome in 4.3% of the patients, adjusted OR per log CK increase, respectively, 3.1 (1.6 to 5.9) for major bleeding and 3.9 (2.5 to 6.1) for the combined outcome; C-index 0.8 for both outcomes. The association between CK and bleeding was independent of the use of thrombolytic therapy.

Discussion

The presented data add to the existing evidence that proportionate to its plasma activity, the ADP-binding enzyme CK is strongly and independently associated with non-fatal and fatal major bleeding during treatment for NSTE-ACS. CK might increase the accuracy of prediction models for major bleeding in patients with NSTE-ACS.

Trial registration number

NCT00000472.

The application of optimisation modelling and geospatial analysis to propose a coronary care network model for patients with ST-elevation myocardial infarction

Background

The incidence of myocardial infarction is increasing in South Africa. Prompt treatment is indicated to reduce mortality. One way of expediting treatment is to set up regional referral recommendations that can guide prehospital providers on the best reperfusion strategy for a particular patient. A coronary care network model for patients who present with ST-elevation myocardial infarction is proposed, using the North West province, of South Africa as a case study.

Methods

Geospatial analysis with network optimisation modelling was applied, to determine which strategy (prehospital thrombolysis, in-hospital thrombolysis or percutaneous coronary intervention) was most appropriate for patients presenting within each of the municipal wards of the North West province.

Results

An efficient and swift recommendation for the optimal reperfusion strategy is obtained using the current model, even in the instance of a large amount of ward data with additional constraints. For most municipal wards (204, 53%) percutaneous coronary intervention is the preferred reperfusion strategy based on proximity. For the remainder of the wards prehospital (138, 36%) or in-hospital (44, 11%) thrombolysis is recommended.

Conclusion

A scalable and efficient method of determining the optimal reperfusion strategy for a patient presenting with ST-elevation myocardial infarction in the North West province, is presented. This approach can serve as a model which can be applied to other settings and can form the basis of regional coronary care network development priorities and resource allocations.

Barriers to the implementation of prehospital thrombolysis in the treatment of ST-segment elevation myocardial infarction in South Africa: An exploratory inquiry

INTRODUCTION

Evidence-based guidelines advocate percutaneous coronary intervention (PCI) as the mainstay reperfusion strategy for ST-segment elevation myocardial infarction (STEMI). However, the South African health system is not well positioned to provide PCI as a 'mainstay strategy'. In response, the Health Professions Council of South Africa approved the use of prehospital thrombolysis (PHT) for emergency care practitioners in 2009. However, since its approval, prehospital thrombolysis has failed to reach a level of systematic uptake indicative of successful implementation. The current study aimed to explore, through a qualitative inquiry, barriers to PHT for the treatment of myocardial infarction within a South African context.

METHODS

A qualitative single-case study design was used where a series of semi-structured interviews were conducted involving purposefully selected participants. The case comprised a nationalised private emergency medical service, and participants were selected in view of relevant experience and knowledge. Requisite data was conceptualised through the consolidated framework for implementation research, and thematic analysis outlined the data coding procedures of the study.

RESULTS

The study identified potential barriers to the implementation of PHT. These comprised cost, logistics, inter-professional collaboration, leadership engagement, and beliefs or scepticism associated with PHT.

CONCLUSION

A lack of strategic implementation has resulted in a poor introduction of evidenced-based prehospital cardiac care, affecting vulnerable populations who may have otherwise benefited from receiving this level of care. Given the time-sensitive nature of STEMI management, and severely limited access to 'primary reperfusion', PHT resembles not only a logical but also appealing solution in the South African context.

Barriers and facilitators to implementing coronary care networks in South Africa: a qualitative study

Background

ST-elevation myocardial infarction (STEMI) is on the rise in sub-Saharan Africa. South Africa consistently fails to deliver timely reperfusion to these patients, possibly due to under-developed coronary care networks (CCN).

Objectives

To determine the current perceived state of CCNs, to determine the barriers to optimising CCNs and to suggest facilitators to optimising CCNs within the South African context.

Methods

A qualitative descriptive approach was employed, by performing two structured in-depth and two focus group interviews (n=4 and 5, respectively), inviting a purposely heterogeneous sample of 11 paramedics (n=4), doctors (n=5), and nurses (n=2) working within different settings in South African CCNs. Recorded interviews were transcribed verbatim and subjected to content analysis.

Results

Participants described an under-resourced, unprioritised and fragmented CCN with significant variation in performance. Barriers to CCN optimisation resided in recognition and diagnosis of STEMI, transport and treatment decisions, and delays. Participants suggested that thrombolysing all STEMI patients could facilitate earlier reperfusion and that pre-hospital thrombolysis should be considered. Participants highlighted the need for regionalised STEMI guidelines, and the need for further research.

Conclusion

Numerous barriers were highlighted. Healthcare policy-makers should prioritise the development of CCNs that is underpinned by evidence and that is contextualised to each specific region within the South African health care system.

Mobile Intensive Care Unit versus Hospital walk-in patients, in the treatment of first episode ST- elevation myocardial infarction

OBJECTIVE

To determine the impact of the attention given by emergency medical services teams working in mobile intensive care units (MICU) versus patients arriving at the hospital under their own means with ST-elevation myocardial infarction (STEMI) event in terms of time to reperfusion (TR), mortality at 30 days and six months.

METHODS

We retrospectively studied 634 consecutive patients with STEMI who underwent primary a percutaneous coronary intervention from January 1st 2015 to December 31st 2018 in a single centre. Depending on the first medical contact patients were classified into two groups, MICU versus walk-in patients. We extracted data on patients' characteristics, symptoms, treatments, times to reperfusion and mortality.

RESULTS

In our study 634 patients were included, of whom 59.0% were initially attended by the MICU. Differences were seen between the two groups in time delays to the first medical contact (120.0 vs 63.0 min; p < 0.001) and TR (208.0 Vs 150.0 min; p < 0.001). Patients attended by the MICUs presented a shorter ICU and hospital stay. The lowest 30-day mortality rate was observed in MICU group: 9.0% in contrast with 4.5%, p = 0.03; remaining after 6 months. The multivariable analysis showed that the initial attention given by MICU to STEMI patients was a protective agent against mortality [OR: 0.32 (0.11-0.90); p = 0.03].

CONCLUSION

Initial attention of the patients with STEMI by doctor-on-board-MICU and available 24 h a day 7 days a week as part of a regional network (CORECAM), was associated with a decrease in the ischemia time, hospital stay and mortality of these patients in our environment.

Challenges in management and prevention of ischemic heart disease in low socioeconomic status people in LLMICs

BACKGROUND

Cardiovascular diseases, principally ischemic heart disease (IHD), are the most important cause of death and disability in the majority of low- and lower-middle-income countries (LLMICs). In these countries, IHD mortality rates are significantly greater in individuals of a low socioeconomic status (SES).

MAIN TEXT

Three important focus areas for decreasing IHD mortality among those of low SES in LLMICs are (1) acute coronary care; (2) cardiac rehabilitation and secondary prevention; and (3) primary prevention. Greater mortality in low SES patients with acute coronary syndrome is due to lack of awareness of symptoms in patients and primary care physicians, delay in reaching healthcare facilities, non-availability of thrombolysis and coronary revascularization, and the non-affordability of expensive medicines (statins, dual anti-platelets, renin-angiotensin system blockers). Facilities for rapid diagnosis and accessible and affordable long-term care at secondary and tertiary care hospitals for IHD care are needed. A strong focus on the social determinants of health (low education, poverty, working and living conditions), greater healthcare financing, and efficient primary care is required. The quality of primary prevention needs to be improved with initiatives to eliminate tobacco and trans-fats and to reduce the consumption of alcohol, refined carbohydrates, and salt along with the promotion of healthy foods and physical activity. Efficient primary care with a focus on management of blood pressure, lipids and diabetes is needed. Task sharing with community health workers, electronic decision support systems, and use of fixed-dose combinations of blood pressure-lowering drugs and statins can substantially reduce risk factors and potentially lead to large reductions in IHD. Finally, training of physicians, nurses, and health workers in IHD prevention should be strengthened.

CONCLUSION

The management and prevention of IHD in individuals with a low SES in LLMICs are poor. Greater availability, access, and affordability for acute coronary syndrome management and secondary prevention are important. Primary prevention should focus on tackling the social determinants of health as well as policy and individual interventions for risk factor control, supported by task sharing and use of technology.

Implementing myocardial infarction systems of care in low/middle-income countries

Ischaemic heart disease is the leading cause of death worldwide, with an increasing trend from 6.1 million deaths in 1990 to 9.5 million in 2016, markedly driven by rates observed in low/middle-income countries (LMIC). Improvements in myocardial infarction (MI) care are crucial for reducing premature mortality. We aimed to evaluate the main challenges for adequate MI care in LMIC, and possible strategies to overcome these existing barriers.

Reperfusion is the cornerstone of MI treatment, but worldwide around 30% of patients are not reperfused, with even lower rates in LMIC. The main challenges are related to delays associated with patient education, late diagnosis and inadequate referral strategies, health infrastructure and insufficient funding. The implementation of regional MI systems of care in LMIC, systematising timely reperfusion strategies, access to intensive care, risk stratification and use of adjunctive medications have shown some successful strategies. Telemedicine support for remote ECG, diagnosis and organisation of referrals has proven to be useful, improving access to reperfusion even in prehospital settings. Organisation of transport and referral hubs based on anticipated delays and development of MI excellence centres have also resulted in better equality of care. Also, education of healthcare staff and task shifting may potentially widen access to optimal therapy.

In conclusion, efforts have been made for the implementation of MI systems of care in LMIC, aiming to address particularities of the health systems. However, the increasing impact of MI in these countries urges the development of further strategies to improve reperfusion and reduce system delays.

Comparative efficacy and safety of reperfusion therapy with fibrinolytic agents in patients with ST-segment elevation myocardial infarction: a systematic review and network meta-analysis

BACKGROUND

Fibrinolytic therapy offers an alternative to mechanical reperfusion for ST-segment elevation myocardial infarction (STEMI) in settings where health-care resources are scarce. Comprehensive evidence comparing different agents is still unavailable. In this study, we examined the effects of various fibrinolytic drugs on clinical outcomes.

METHODS

We did a network meta-analysis based on a systematic review of randomised controlled trials comparing fibrinolytic drugs in patients with STEMI. Several databases were searched from inception up to Feb 28, 2017. We included only randomised controlled trials that compared fibrinolytic agents as a reperfusion therapy in adult patients with STEMI, whether given alone or in combination with adjunctive antithrombotic therapy, against other fibrinolytic agents, a placebo, or no treatment. Only trials investigating agents with an approved indication of reperfusion therapy in STEMI (streptokinase, tenecteplase, alteplase, and reteplase) were included. The primary efficacy outcome was all-cause mortality within 30-35 days and the primary safety outcome was major bleeding. This study is registered with PROSPERO (CRD42016042131).

FINDINGS

A total of 40 eligible studies involving 128 071 patients treated with 12 different fibrinolytic regimens were assessed. Compared with accelerated infusion of alteplase with parenteral anticoagulants as background therapy, streptokinase and non-accelerated infusion of alteplase were significantly associated with an increased risk of all-cause mortality (risk ratio [RR] 1·14 [95% CI 1·05-1·24] for streptokinase plus parenteral anticoagulants; RR 1·26 [1·10-1·45] for non-accelerated alteplase plus parenteral anticoagulants). No significant difference in mortality risk was recorded between accelerated infusion of alteplase, tenecteplase, and reteplase with parenteral anticoagulants as background therapy. For major bleeding, a tenecteplase-based regimen tended to be associated with lower risk of bleeding compared with other regimens (RR 0·79 [95% CI 0·63-1·00]). The addition of glycoprotein IIb or IIIa inhibitors to fibrinolytic therapy increased the risk of major bleeding by 1·27-8·82-times compared with accelerated infusion alteplase plus parenteral anticoagulants (RR 1·47 [95% CI 1·10-1·98] for tenecteplase plus parenteral anticoagulants plus glycoprotein inhibitors; RR 1·88 [1·24-2·86] for reteplase plus parenteral anticoagulants plus glycoprotein inhibitors).

INTERPRETATION

Significant differences exist among various fibrinolytic regimens as reperfusion therapy in STEMI and alteplase (accelerated infusion), tenecteplase, and reteplase should be considered over streptokinase and non-accelerated infusion of alteplase. The addition of glycoprotein IIb or IIIa inhibitors to fibrinolytic therapy should be discouraged.

FUNDING

None.

Physician perceptions and recommendations about pre-hospital emergency medical services for patients with ST-elevation acute myocardial infarction in Abu Dhabi

Introduction

Physician perceptions about emergency medical services (EMS) are important determinants of improving pre-hospital care for cardiac emergencies. No data exist on physician attitudes towards EMS care of patients with ST-Elevation Myocardial Infarction (STEMI) in the Emirate of Abu Dhabi.

Objectives

To describe the perceptions towards EMS among physicians caring for patients with STEMI in Abu Dhabi.

Methods

We surveyed a convenience sample of physicians involved in the care of patients with STEMI (emergency medicine, cardiology, cardiothoracic surgery and intensive care) in four government facilities with 24/7 Primary PCI in the Emirate of Abu Dhabi. Surveys were distributed using dedicated email links, and used 5-point Likert scales to assess perceptions and attitudes to EMS.

Results

Of 106 physician respondents, most were male (82%), practicing in emergency medicine (47%) or cardiology (44%) and the majority (63%) had been in practice for >10 years. Less than half of the responders (42%) were “Somewhat Satisfied” (35%) or “Very Satisfied” (7%) with current EMS level of care for STEMI patients. Most respondents were “Very Likely” (67%) to advise a patient with a cardiac emergency to use EMS, but only 39% felt the same for themselves or their family. Most responders were supportive (i.e. “Strongly Agree”) of the following steps to improve EMS care: 12-lead ECG and telemetry to ED by EMS (69%), EMS triage of STEMI to PCI facilities (65%), and activation of PCI teams by EMS (58%). Only 19% were supportive of pre-hospital fibrinolytics by EMS. There were no significant differences in the responses among the specialties.

Conclusions

Most physicians involved in STEMI care in Abu Dhabi are very likely to advise patients to use EMS for a cardiac emergency, but less likely to do so for themselves or their families. Different specialties had concordant opinions regarding steps to improve pre-hospital EMS care for STEMI.