What are the challenges to implementing a pharmacoinvasive strategy in ST‑elevation myocardial infarction (STEMI)?

Challenges to Implementing Pharmacoinvasive Strategy in STEMI

The most significant barriers to implementing pharmacoinvasive strategy in STEMI are the absence of regional systems of care, inadequate financial and personnel resources, lack of emergency medical services infrastructure, and logistical impediments to timely patient transfer—particularly in low- and middle-income countries where these challenges are most pronounced. 1

Infrastructure and System-Level Challenges

Absence of Regional STEMI Networks

• Regional systems of care for STEMI are virtually nonexistent in low- and middle-income countries (LMICs), representing the single biggest barrier to uniform STEMI care. 1
• Emergency medical services systems are fundamentally lacking in resource-limited settings, preventing the coordinated approach necessary for pharmacoinvasive strategies. 1
• Up to one-third of eligible STEMI patients in industrialized countries receive no reperfusion treatment, a problem that requires development and implementation of STEMI networks. 2

Transfer and Logistics Barriers

• Roadblocks to routine transfer include lack of ambulance-based ECGs, mandates in many jurisdictions to deliver patients to the nearest hospital regardless of interventional capability, and financial disincentives to transfer. 1
• Lack of adequate staffing and beds at tertiary hospitals often requires diversion of STEMI patients, resulting in excessively long transfer times. 1
• Public policy changes are necessary to increase timely access to primary PCI, with economic implications that must be considered. 1

Knowledge Gaps and Evidence Limitations

Fibrinolytic Agent Selection

• The efficacy of streptokinase—the most cost-effective option in LMICs—has not been tested specifically in pharmacoinvasive strategies in randomized controlled trials, despite tenecteplase being used in landmark trials like STREAM. 1
• Fibrin-specific thrombolytics such as tenecteplase and tissue plasminogen activator can be cost-prohibitive compared with streptokinase in LMICs. 1

Antiplatelet Therapy Uncertainties

• Which antiplatelet agent is optimal in pharmacoinvasive strategies remains unclear, particularly given that the TREAT trial showed ticagrelor did not reduce cardiovascular events compared with clopidogrel among patients receiving fibrinolytic therapy. 1
• Clinical pharmacology studies in East Asian populations have reported higher exposure to ticagrelor leading to higher platelet inhibition compared with whites, with at least two prospective trials demonstrating concerning safety signals. 1

Late Presentation Issues

• Patients with STEMI in LMICs frequently present late with longer ischemic times. 1
• Whether the resultant longer delay in PCI after fibrinolytic therapy provides the same efficacy as noted in STREAM and TRANSFER-AMI trials remains unknown. 1

Resource and Economic Constraints

Financial Barriers

• Lack of adequate financial and capital resources to set up regional systems and to administer and maintain them successfully is a major deficiency in LMICs. 1
• The cost differential between bare metal stents and drug-eluting stents creates additional economic pressures in resource-limited settings. 3

Personnel and Equipment Limitations

• Insufficient personnel resources to staff 24/7 primary PCI-capable centers that can deliver consistent service. 1
• Lack of equipment for pre-hospital ECG diagnosis and transmission systems in rural and underserved areas. 4

Clinical Implementation Challenges

Volume and Quality of Care

• A strong relationship exists between annual number of primary PCI procedures performed and survival on both institutional and individual operator levels, making low-volume centers problematic. 1
• System-wide implementation requires increasing institutional and operator experience through volume to optimize outcomes. 1

Timing and Coordination Complexities

• The critical decision point of whether to administer fibrinolysis versus immediate transfer depends on accurate estimation of transfer times, which is often unreliable. 1
• Coordination between non-PCI-capable hospitals and PCI centers for planned angiography at 3-24 hours after fibrinolysis requires sophisticated communication systems. 1, 3

Health Services Research Gaps

Population Access Mapping

• Accurate mapping of what proportion of the population can already access existing thrombolytic/PCI centers in a timely fashion is largely lacking, making resource planning difficult. 1
• Without this data, recommendations can provide only a general overview of implementation principles rather than targeted interventions. 1

Quality Measurement Systems

• Lack of established quality indicators to measure and audit pharmacoinvasive strategy implementation in real-world settings. 1
• Insufficient data from real-world registries comparing pharmacoinvasive strategies to primary PCI in diverse geographic and economic contexts. 5

Critical Pitfalls in Implementation

Bleeding Risk Management

• There is a propensity for more bleeding with pharmacoinvasive strategy compared to primary PCI (odds ratio: 2.02), which approached statistical significance in real-world system comparisons. 6
• Balancing efficacy and bleeding risk with optimal antiplatelet and anticoagulant regimens remains challenging, particularly with newer agents. 4

Patient Selection Challenges

• High-risk patients (anterior infarction, left bundle-branch block, Killip class >1) require immediate transfer even after fibrinolysis, complicating triage decisions. 1
• Patients presenting within 2 hours of symptom onset with excessive transfer delays represent a particularly difficult decision point. 1