Can the ARC-HBR (Acute Coronary Syndrome Risk Score - High Bleeding Risk) score be used in patients with Acute Coronary Syndrome (ACS) undergoing fibrinolytic therapy?

ARC-HBR Score in ACS Patients Undergoing Fibrinolytic Therapy

The ARC-HBR score should not be used in ACS patients undergoing fibrinolytic therapy, as it was specifically developed and validated only for patients undergoing percutaneous coronary intervention (PCI), not for fibrinolysis. 1

Why ARC-HBR Is Not Applicable to Fibrinolysis

Development Context

• The ARC-HBR criteria were explicitly created to provide consistency for clinical trials evaluating safety and effectiveness of devices and drug regimens specifically for patients undergoing PCI, not fibrinolytic therapy 1
• The score has not been validated in medically treated patients or those receiving fibrinolytic therapy 1
• All validation studies of ARC-HBR have been conducted exclusively in PCI populations 2, 3, 4

Practical Limitations

• Several ARC-HBR criteria are quite detailed and difficult to apply in routine clinical practice, making them particularly impractical in the time-sensitive pre-hospital or emergency setting where fibrinolysis decisions must be made rapidly 1
• The score requires information that may not be immediately available when deciding on fibrinolytic therapy 1

What to Use Instead for Fibrinolysis Bleeding Risk

Pre-Hospital and Emergency Setting

Use absolute and relative contraindications to fibrinolytic therapy as your primary bleeding risk assessment tool 1

Absolute Contraindications (Never Give Fibrinolytics):

• Previous intracranial hemorrhage or hemorrhagic stroke at any time 1
• Ischemic stroke within 6 months 1
• Central nervous system neoplasm or arteriovenous malformation 1
• Recent major trauma/surgery/head injury within 3 weeks 1
• Recent gastrointestinal bleeding within 1 month 1
• Known bleeding disorder (excluding menses) 1
• Aortic dissection or pericarditis 1
• Non-compressible punctures within 24 hours 1

Relative Contraindications (Weigh Risk vs. Benefit):

• Transient ischemic attack within 6 months 1
• Oral anticoagulant therapy 1
• Pregnancy or less than 1 week postpartum 1
• Refractory hypertension (SBP >180 mmHg and/or DBP >110 mmHg) 1
• Advanced liver disease 1
• Infective endocarditis 1
• Active peptic ulcer 1
• Prolonged or traumatic resuscitation 1

Clinical Risk Factors from GRACE Registry

Use these simple clinical parameters to identify high bleeding risk when fibrinolysis is being considered 1:

• Age >80 years (most important predictor) 1
• Female gender 1
• Low body weight (<70 kg for females, <80 kg for males) 1
• History of renal failure 1
• History of bleeding 1
• Low blood pressure on presentation 1
• Current use of antithrombotic medications (antiplatelets, anticoagulants, NSAIDs) 1

Risk Stratification for Intracranial Hemorrhage

The number of risk factors predicts stroke risk with fibrinolysis 1:

• 0 risk factors: 0.25% stroke risk 1
• 3 risk factors: 2.5% stroke risk 1

Key risk factors for intracranial hemorrhage:

• Age ≥65 years 1
• Low body weight ≤70 kg 1
• Hypertension on presentation (≥180/110 mmHg) 1
• Use of tissue plasminogen activator (rtPA) 1

Alternative Bleeding Risk Scores for ACS

For Patients Undergoing Coronary Angiography (Not Fibrinolysis)

• CRUSADE score is the most discriminatory for major bleeding in ACS patients undergoing coronary angiography 1
• ACUITY bleeding risk score has reasonable predictive value but is less discriminatory than CRUSADE 1
• Both scores may be considered (Class IIb, Level B recommendation) but only in patients undergoing coronary angiography, not fibrinolysis 1

Limitations of These Scores

• CRUSADE requires biological parameters usually unavailable in the pre-hospital setting 1
• Changes in interventional practice (radial access, newer antithrombotic treatments) may modify predictive value 1
• Predictive value not established in medically treated patients 1

Critical Decision Algorithm for Fibrinolysis

When considering fibrinolysis in STEMI patients:

1. Check for absolute contraindications first - if any present, fibrinolysis is contraindicated (Class III) 1

2. Assess clinical bleeding risk factors - if multiple GRACE risk factors present (especially age >80, low weight, renal failure, bleeding history), bleeding risk may outweigh benefit 1

3. Consider relative contraindications - weigh against ischemic benefit based on infarct size (extensive ECG changes favor fibrinolysis despite some bleeding risk) 1

4. If high bleeding risk identified, prefer primary PCI strategy if available within 120 minutes of first medical contact 1

5. If bleeding risk seems to overbalance expected benefit, withhold pre-hospital fibrinolysis and arrange rapid transfer to PCI-capable center 1

Common Pitfalls to Avoid

• Do not attempt to apply ARC-HBR criteria to fibrinolysis decisions - this score is invalid outside the PCI population 1
• Do not use HAS-BLED score for ACS bleeding risk - it has not been validated in acute coronary syndrome settings 1
• Do not give fibrinolytics to patients with NSTE-ACS - fibrinolytic therapy is contraindicated (Class III: Harm) and increases mortality in non-ST-elevation ACS 1
• Do not delay fibrinolysis to calculate complex bleeding scores - use simple clinical assessment of contraindications and risk factors 1
• Do not ignore the time-sensitivity of fibrinolysis - mortality benefit decreases with longer symptom-to-treatment times, and bleeding risk assessment must be rapid 1