Prehospital fibrinolysis versus primary percutaneous coronary intervention in ST-elevation myocardial infarction: a systematic review and meta-analysis of randomized controlled trials

Clinical Research in Prehospital Care: Current and Future Challenges

Prehospital care plays a critical role in improving patient outcomes, particularly in cases of time-sensitive emergencies such as trauma, cardiac failure, stroke, bleeding, breathing difficulties, systemic infections, etc. In recent years, there has been a growing interest in clinical research in prehospital care, and several challenges and opportunities have emerged. There is an urgent need to adapt clinical research methodology to a context of prehospital care. At the same time, there are many barriers in prehospital research due to the complex context, posing unique challenges for research, development, and evaluation. Among these, this review allows the highlighting of limited resources and infrastructure, ethical and regulatory considerations, time constraints, privacy, safety concerns, data collection and analysis, selection of a homogeneous study group, etc. The analysis of the literature also highlights solutions such as strong collaboration between emergency medical services (EMS) and hospital care, use of (mobile) health technologies and artificial intelligence, use of standardized protocols and guidelines, etc. Overall, the purpose of this narrative review is to examine the current state of clinical research in prehospital care and identify gaps in knowledge, including the challenges and opportunities for future research.

Neu3 Sialidase Activates the RISK Cardioprotective Signaling Pathway during Ischemia and Reperfusion Injury (IRI)

Coronary reperfusion strategies are life-saving approaches to restore blood flow to cardiac tissue after acute myocardial infarction (AMI). However, the sudden restoration of normal blood flow leads to ischemia and reperfusion injury (IRI), which results in cardiomyoblast death, irreversible tissue degeneration, and heart failure. The molecular mechanism of IRI is not fully understood, and there are no effective cardioprotective strategies to prevent it. In this study, we show that activation of sialidase-3, a glycohydrolytic enzyme that cleaves sialic acid residues from glycoconjugates, is cardioprotective by triggering RISK pro-survival signaling pathways. We found that overexpression of Neu3 significantly increased cardiomyoblast resistance to IRI through activation of HIF-1α and Akt/Erk signaling pathways. This raises the possibility of using Sialidase-3 activation as a cardioprotective reperfusion strategy after myocardial infarction.

A Review of the Role of the Antiplatelet Drug Ticagrelor in the Management of Acute Coronary Syndrome, Acute Thrombotic Disease, and Other Diseases

P2Y12 inhibitors, including aspirin, are key components of dual-antiplatelet therapy (DAPT), which is the optimal therapeutic strategy for preventing arterial thrombosis in patients with acute coronary syndromes (ACS) who underwent stent implantation. Ticagrelor is a cyclopentyl-triazole pyrimidine antiplatelet drug that was the first reversible oral P2Y12 receptor antagonist. Compared with clopidogrel, ticagrelor exerts a faster onset and offset of function by reversible and selective inhibition of platelet aggregation in ACS patients, including those with coronary artery blood revascularization. Despite improvement in stent materials, stent thrombosis (ST) due to high on-treatment platelet reactivity (HPR) to clopidogrel continues to occur. In addition to antiplatelet aggregation, ticagrelor displays pleiotropic cardioprotective effects, including improving coronary blood flow, reducing myocardial necrosis after an ischemic event, and anti-inflammatory effects. The benefits of ticagrelor over clopidogrel were consistent in the PLATO results, with lower incidence of the primary endpoint. Also, in 2020, the findings from the phase 3 THALES trial (NCT03354429) showed that aspirin combined with 90 mg of ticagrelor significantly reduced the rates of stroke and death compared with aspirin alone in patients with AIS or TIA. Here, we review recent research on the superiority of ticagrelor over clopidogrel, discuss the pharmacological mechanism, and present future perspectives. This review aims to present the roles of ticagrelor in the management of acute coronary syndrome, acute thrombotic disease, and other diseases.

Residual platelet reactivity, thrombus burden and myocardial reperfusion in patients treated by PCI after successful pre-hospital fibrinolysis compared to primary PCI

We compared residual platelet reactivity and post PCI atherothrombotic burden using OFDI in patients successfully treated by primary PCI versus pharmacoinvasive approach (PI) defined as PCI after successful pre-hospital fibrinolysis. Despite pre-hospital P2Y12-inhibitor loading dose, high rates of high on-treatment platelet reactivity were found at the time of PCI in both groups. Primary PCI patients had higher post stenting thrombus burden and lower rates of final normal myocardial blush grade compared to PI. These findings support the use of a pharmacoinvasive reperfusion strategy especially when primary PCI cannot be timely performed.

Reduction of door-to-balloon time in patients with ST-elevation myocardial infarction by single-catheter primary percutaneous coronary intervention method

Objectives

The objectives of this study is to confirm reduction of door‐to‐balloon (D2B) time with single‐catheter percutaneous coronary intervention (SC‐PCI) method.

Background

Reduction of total ischemic time is important in the emergency treatment of ST‐elevation myocardial infarction (STEMI). There have been no established methods in primary percutaneous coronary intervention (PCI) to shorten ischemic time via radial access. Ikari left curve was reported as a universal guiding catheter for left and right coronary arteries. Several procedure steps can be skipped by SC‐PCI method as the advantage of a universal catheter.

Methods

This study is a retrospective analysis of a total of 1,275 consecutive STEMI cases treated with primary PCI in 14 hospitals. Patients were divided into two groups, SC‐PCI method (n = 298) and conventional PCI method (n = 977). Primary endpoints were door‐to‐balloon (D2B) time and radiation exposure dose.

Results

The mean age was 68 ± 13 years old. Radial access was used in 85% of participants. PCI success was achieved in 99.5% of participants and the SC‐PCI method was successfully performed in 92.6%. The D2B time was shorter (68 ± 46 vs. 74 ± 50 min, respectively; p = .02), and the radiation exposure dose was lower (1,664 ± 970 vs. 2008 ± 1,605 mGy, respectively; p < .0001) in the SC‐PCI group than in the conventional group.

Conclusion

Primary PCI with SC‐PCI method for patients with STEMI demonstrated shorter D2B time and lower radiation exposure dose.

Management of ST Elevation Myocardial Infarction (STEMI) in Different Settings

ST-segment elevation myocardial infarction (STEMI) is a life-threatening condition that requires emergent, complex, well-coordinated treatment. Although the primary goal of treatment is simple to describe-reperfusion as quickly as possible-the management process is complicated and is affected by multiple factors including location, patient, and practitioner characteristics. Hence, this narrative review will discuss the recommended management and treatment strategies of STEMI in the circumstances.

Fibrinolysis vs. primary percutaneous coronary intervention for ST-segment elevation myocardial infarction cardiogenic shock

AIMS

There are limited contemporary data on the use of initial fibrinolysis in ST-segment elevation myocardial infarction cardiogenic shock (STEMI-CS). This study sought to compare the outcomes of STEMI-CS receiving initial fibrinolysis vs. primary percutaneous coronary intervention (PPCI).

METHODS

Using the National (Nationwide) Inpatient Sample from 2009 to 2017, a comparative effectiveness study of adult (>18 years) STEMI-CS admissions receiving pre-hospital/in-hospital fibrinolysis were compared with those receiving PPCI. Admissions with alternate indications for fibrinolysis and STEMI-CS managed medically or with surgical revascularization (without fibrinolysis) were excluded. Outcomes of interest included in-hospital mortality, development of non-cardiac organ failure, complications, hospital length of stay, hospitalization costs, use of palliative care, and do-not-resuscitate status.

RESULTS

During 2009-2017, 5297 and 110 452 admissions received initial fibrinolysis and PPCI, respectively. Compared with those receiving PPCI, the fibrinolysis group was more often non-White, with lower co-morbidity, and admitted on weekends and to small rural hospitals (all P < 0.001). In the fibrinolysis group, 95.3%, 77.4%, and 15.7% received angiography, PCI, and coronary artery bypass grafting, respectively. The fibrinolysis group had higher rates of haemorrhagic complications (13.5% vs. 9.9%; P < 0.001). The fibrinolysis group had comparable all-cause in-hospital mortality [logistic regression analysis: 28.8% vs. 28.5%; propensity-matched analysis: 30.8% vs. 30.3%; adjusted odds ratio 0.97 (95% confidence interval 0.90-1.05); P = 0.50]. The fibrinolysis group had comparable rates of acute organ failure, hospital length of stay, rates of palliative care referrals, do-not-resuscitate status use, and lesser hospitalization costs.

CONCLUSIONS

The use of initial fibrinolysis had comparable in-hospital mortality than those receiving PPCI in STEMI-CS in the contemporary era in this large national observational study.

The comparison of procedural and clinical outcomes of thrombolytic-facilitated and primary percutaneous coronary intervention in patients with acute ST-elevation myocardial infarction (STEMI): Findings from PROVE/ACS study

BACKGROUND

There is still a controversy in the preferred method of reperfusion in acute ST-segment elevation myocardial infarction (STEMI), when the achievement of well-defined "golden time" is difficult. We sought to evaluate the procedural and in-hospital outcomes of the strategy of "thrombolytic administration and rescue or routine percutaneous coronary intervention (PCI)" versus "primary PCI (PPCI)" strategy in acute STEMI.

METHODS

In this observational prospective study, the data of 237 patients with acute STEMI presented or referred to Chamran Cardiovascular Research Center in Isfahan, Iran, were collected (PROVE/ACS study). Baseline characteristics, thrombolysis in myocardial infarction (TIMI) flow grade of infarct-related artery (IRA), left ventricular ejection fraction (LVEF), and in-hospital outcomes were evaluated.

RESULTS

The mean age of patients was 61.4 ± 13.0 years, 86.9% were men, 13.1% were diabetic, and 67.9% had anterior STEMI. Patients in the "thrombolytic then PCI" group were younger, more smoker, more often male with higher body weight and lower systolic blood pressure (SBP). The pre-PCI TIMI flow grade 3 was more often seen in the "thrombolytic then PCI" group (39.4% vs. 21.0%, P < 0.001) and less thrombectomy was performed in this group of patients (12.9% vs. 26.7%, P = 0.011). Time to reperfusion was significantly longer in PPCI group (182.4 ± 233.7 minutes vs. 44.6 ± 93.4 minutes, respectively, P < 0.001). No difference in mortality, mean of LVEF, and incidence of atrial fibrillation (AF) was observed in two groups.

CONCLUSION

If the PPCI strategy could not be performed in the golden time, the strategy of thrombolytic administration and rescue or routine PCI leads to more initial IRA patency and less thrombectomy with similar clinical outcomes.

Outcomes of a Provincial Myocardial Infarction Reperfusion Strategy: A Population-Based, Retrospective Cohort Study

BACKGROUND

Fibrinolysis is an acceptable treatment for acute ST-segment elevation myocardial infarction (STEMI) when primary percutaneous coronary intervention (PCI) cannot be performed within 120 minutes. The American Heart Association has recommended Emergency Medical Services (EMS) interventions such as prehospital fibrinolysis (PHF), prehospital electrocardiogram (ECG), and hospital bypass direct to PCI center. Nova Scotia, Canada has incorporated these interventions into a unique province-wide approach to STEMI care. A retrospective cohort analysis comparing the primary outcome of 30-day mortality for patients receiving either prehospital or emergency department (ED) fibrinolysis (EDF) to patients transported directly by EMS from community or regional ED for primary PCI was conducted.

METHODS

This retrospective, population-based cohort study included all STEMI patients in Nova Scotia who survived to hospital admission from July 2011 through July 2013. Three provincial databases were used to collect demographic, 30-day mortality, hospital readmission, and rescue PCI data. The results were grouped and compared according to reperfusion strategy received: PHF, EDF, patients brought by ambulance via EMS direct to PCI (EMS to PCI), and ED to PCI (ED to PCI).

RESULTS

There were 1,071 STEMI patients included with 145 PHF, 606 EDF, 98 EMS to PCI, and 222 ED to PCI. There were no significant differences in 30-day mortality across groups (n, %): PHF 5(3); EDF 36(6); EHS to PCI <5(2); and ED to PCI 10(4); P = .28. There was no significant difference in patients receiving fibrinolysis who underwent rescue PCI.

CONCLUSIONS

Prehospital fibrinolysis incorporated into a province-wide approach to STEMI treatment is feasible with no observed difference in patient 30-day mortality outcomes observed.

A retrospective study of an invasive versus conservative strategy in patients aged ≥80 years with acute ST-segment elevation myocardial infarction

Objective

To investigate what is the most appropriate strategy for patients with ST-segment elevation myocardial infarction (STEMI) aged ≥80 years in China.

Methods

This cohort study retrospectively enrolled patients with STEMI aged ≥80 years old and grouped them according to the treatment strategy that was used: a conservative treatment strategy or an invasive treatment strategy. Factors associated with whether to perform an invasive intervention, in-hospital death and a good prognosis were investigated using logistic regression analyses.

Results

A total of 232 patients were enrolled: conservative treatment group ( n = 93) and invasive treatment group ( n = 139). Patients in the invasive treatment group had a better prognosis and lower incidence of adverse events compared with the conservative treatment group. Advanced age, creatinine level and a higher Killip class were inversely correlated with whether to perform an invasive intervention, while the use of beta-receptor-blocking agents was a favourable factor for invasive treatment. Hypertension and a higher Killip class were risk factors for in-hospital death, while the use of beta-receptor-blocking agents and diuretics decreased the risk of in-hospital death.

Conclusions

An invasive treatment strategy was superior to a conservative treatment strategy in patients with STEMI aged ≥80 years.

Use of ticagrelor alongside fibrinolytic therapy in patients with ST-segment elevation myocardial infarction: Practical perspectives based on data from the TREAT study

Primary percutaneous coronary intervention (PCI) is the preferred reperfusion method in patients with ST-segment elevation myocardial infarction (STEMI). In patients with STEMI who cannot undergo timely primary PCI, pharmacoinvasive treatment is recommended, comprising immediate fibrinolytic therapy with subsequent coronary angiography and rescue PCI if needed. Improving clinical outcomes following fibrinolysis remains of great importance for the many patients globally for whom rapid treatment with primary PCI is not possible. For patients with acute coronary syndrome who underwent primary PCI, the PLATO trial demonstrated superior efficacy of ticagrelor relative to clopidogrel. Results in the predefined subgroup of patients with STEMI were consistent with the overall PLATO trial. Patients who received fibrinolytic therapy in the 24 hours before randomization were excluded from PLATO, and there is thus a lack of data on the safety of using ticagrelor in conjunction with fibrinolytic therapy in the first 24 hours after STEMI. The TREAT study addresses this knowledge gap; patients with STEMI who had symptom onset within the previous 24 hours and had received fibrinolytic therapy (of whom 89.4% had also received clopidogrel) were randomized to treatment with ticagrelor or clopidogrel (median time between fibrinolysis and randomization: 11.5 hours). At 30 days, ticagrelor was found to be non-inferior to clopidogrel for the primary safety outcome of Thrombolysis in Myocardial Infarction (TIMI)-defined first major bleeding. Considering together the results of the PLATO and TREAT studies, initiating or switching to treatment with ticagrelor within the first 24 hours after STEMI in patients receiving fibrinolysis is reasonable.

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.

Plaque erosion versus rupture characterization by optical frequency domain imaging before and after coronary stenting following successful fibrinolysis for ST-segment elevation myocardial infarction

Intracoronary thrombus burden affects the quality of myocardial reperfusion in the setting of ST-elevation myocardial infarction (STEMI). We aimed to study the characteristics of the plaque and thrombus assessed by intracoronary optical frequency domain imaging (OFDI) according to the presence of plaque rupture or erosion in STEMI patients treated with successful fibrinolysis. Pre-stenting thrombus and post-stenting atherothrombotic burden were compared between plaque rupture and erosion. Twenty-seven consecutive patients were included: 17 (63%) had OFDI-plaque rupture and 10 (37%) had OFDI-erosion. Thrombus volume and burden were significantly higher in case of rupture compared to erosion at baseline (13.4 ± 18.4 vs 2.8 ± 2.3 mm³; p = 0.03 and 33.8 ± 17.5 vs 17.5 ± 9.9%; p = 0.007, respectively). In the rupture group, the core of the thrombus consisted dominantly of red thrombus evenly distributed along the entire culprit plaque. In the erosion group, it consisted dominantly of white thrombus with a focal distribution near the minimal lumen area zone. After stenting, the atherothrombotic volume, burden and its distribution, as well as angiographic estimators of myocardial reperfusion were similar between groups. Our study showed that pre-PCI thrombus amount, typesetting and distribution are mainly linked to the underlying mechanism of STEMI. After stenting, the atherothrombotic burden and its distribution were similar between the groups.

Point of Care Tests VerifyNow P2Y12 and INNOVANCE PFA P2Y Compared to Light Transmittance Aggregometry After Fibrinolysis

Detection of high on-treatment platelet reactivity (HPR) by point-of-care tests has not been validated after successful fibrinolysis for ST-elevation myocardial infarction. We assessed the validity of the point-of-care VerifyNow P2Y12 (VN) and INNOVANCE PFA P2Y (PFA) tests on HPR compared to light transmittance aggregometry (LTA) in these patients. The HPR was identified in 10 (34.5%) patients, 15 (51.7%) patients, and 14 (50%) patients using LTA, VN, and PFA, respectively. Discrepancies were observed between the tests despite significant correlations between platelet reactivity measures by LTA and VN (r = 0.74; P < .0001) and LTA and PFA (r = .75; P < .0001). Compared to LTA, VN and PFA were associated with a 92% and 53% and 92% and 64% positive predictive value (PPV) and negative predictive value (NPV), respectively, in detecting HPR. When combined, VN and PFA results yielded 90% and 100% PPV and NPV values if discrepancies between the 2 tests were considered as non-HPR. The VN or PFA identify patients without HPR correctly but overestimate the proportion of HPR patients. The association of the 2 tests, in case of HPR, improves the accuracy of the detection of HPR.

Trends in clinical outcomes and survival following prehospital thrombolytic therapy given by ambulance clinicians for ST-elevation myocardial infarction in rural sub-arctic Norway

BACKGROUND:

Prehospital thrombolytic therapy given by ambulance emergency medical services to patients with acute ST-segment elevation myocardial infarction (STEMI) may produce earlier reperfusion than percutaneous coronary intervention. Clinical results from prehospital thrombolytic therapy in rural areas are scarce.

METHODS:

We studied outcomes during 11 years of a prehospital thrombolytic therapy system in rural sub-arctic Norway. Ambulance personnel gave protocol basic treatment and transmitted electrocardiograms to hospital physicians who made the decision for prehospital thrombolytic therapy. The study was divided into three time periods; 2000-2003, 2004-2007 and 2008-2011.

RESULTS:

A total of 385 STEMI patients received prehospital thrombolytic therapy, median patient age was 61.2 years, and 77% were men. Time saved by prehospital reperfusion therapy was 131 minutes. The proportion who got prehospital thrombolytic therapy within 2 hours of symptom onset increased from 21% in 2000-2003 to 39% in 2008-2011 ( P=0.003). The proportion who underwent coronary angiography or percutaneous coronary intervention within 24 hours of first medical contact increased from 56.4% to 95.4% ( P<0.001). Post-STEMI systolic heart failure decreased from 19.4% to 8.1% ( P=0.02), while 1-year mortality fell, non-significantly, by 50% over time to reach 5.6%. Thirteen patients suffered acute out-of-hospital cardiac arrest; all were successfully defibrillated. Ten patients had major bleeding events (2.6%).

CONCLUSION:

A decentralised prehospital thrombolytic therapy system based on ambulance personnel, telemetry and centralised 7/24 invasive diagnosis and treatment service, combined with system maturation over time, was associated with earlier reperfusion, improved clinical outcomes and better survival. Prehospital thrombolytic therapy is a feasible and safe intervention used in rural settings with long evacuation lines to percutaneous coronary intervention facilities.

Antithrombotic Therapy for ACS in Elderly Patients

BACKGROUND

Patients over 75 account for more than one third of those presenting with myocardial infarction and more than 50% of intrahospital mortality. There are no specific guidelines for the management of acute coronary syndromes (ACS) in the elderly.

SETTING

Although antithrombotic therapy seems to be effective and safe in such patients, it requires specific precautions and treatment adjustments because of the higher bleeding risk due to comorbidities such as renal function impairment and malnutrition.

RESULTS

Scientific evidence concerning elderly patients is scarce as they are either excluded or underrepresented in most randomized trials. Overall, the antithrombotic therapy needs to be adapted to avoid complications, mainly bleeding complications, without compromising the effectiveness of the treatment in this high-risk population.

CONCLUSION

In the present paper, we review the current treatment strategies in ACS while focusing on data concerning the elderly, according to available data in pivotal trials and in both AHA/ACC and ESC guidelines.