What study supports the 90-minute door-to-balloon (time from hospital arrival to angioplasty) time for patients with acute myocardial infarction (heart attack)?

The 90-Minute Door-to-Balloon Time Standard

The 90-minute door-to-balloon time benchmark is not based on a single researcher's study, but rather emerged from ACC/AHA guideline committees synthesizing multiple randomized trials and observational data showing that mortality increases continuously with longer delays to reperfusion in STEMI patients. 1

Origin and Evolution of the Standard

The 90-minute door-to-balloon time goal was established through systematic review of evidence rather than a single landmark study. The ACC/AHA Task Force progressively refined this target:

• The guideline committees lowered the acceptable time from 120 minutes to 90 minutes to maximize reperfusion benefits, recognizing that faster treatment consistently improves outcomes 2
• This 90-minute target represents a systems goal—the longest acceptable time—not an "ideal" time, and many high-performing centers achieve median times of 60-70 minutes 1, 3
• The standard applies whether patients self-transport to a PCI-capable hospital or arrive via EMS 1

Key Evidence Supporting Time-Dependent Mortality

The rationale for the 90-minute benchmark comes from multiple data sources demonstrating continuous harm with delays:

• Analysis of 43,801 STEMI patients in the National Cardiovascular Data Registry showed mortality increases in a continuous, nonlinear fashion with any delay: 30 minutes = 3.0%, 60 minutes = 3.5%, 90 minutes = 4.3%, 120 minutes = 5.6%, 150 minutes = 7.0%, 180 minutes = 8.4% (P < 0.001) 1
• Rather than accepting 90 minutes as adequate, this evidence suggests an "as-soon-as-possible" standard 1, 3
• In elderly patients (≥65 years), door-to-balloon time showed similar continuous increases in 1-year mortality: 30 minutes = 8.8%, 60 minutes = 12.9%, 90 minutes = 16.6%, 120 minutes = 19.9%, 150 minutes = 22.9% 4

Supporting Randomized Trial Evidence

The guideline committees synthesized data from multiple randomized trials:

• Meta-analysis of 23 randomized trials (n=7,739) comparing primary PCI to fibrinolysis demonstrated superiority of PCI for death, reinfarction, and stroke 1
• Five randomized trials (n=2,466) showed mortality reduction with PCI versus fibrinolysis (6.8% vs 9.6%, relative risk 0.69, P=0.01) when mean time to treatment was delayed only 44 minutes 1
• These trials established PCI superiority but also highlighted that excessive delays negate the benefit over immediate fibrinolysis 1

Contemporary Research Validating Faster Times

Recent observational studies support even more aggressive time targets:

• Patients with door-to-balloon time <60 minutes had significantly lower 30-day mortality (8.0% absolute reduction), better TIMI flow, and fewer recurrent MIs compared to 60-90 minutes 5
• Every 30-minute reduction in door-to-balloon time showed continuous mortality benefit: 90 to 60 minutes (absolute risk reduction 2.4%, NNT 42), 60 to 30 minutes (absolute risk reduction 2.0%, NNT 49) 6
• Door-to-balloon time <45 minutes showed 70% mortality reduction compared to >90 minutes (adjusted HR 0.30,95% CI 0.19-0.42) 6

Critical Implementation Context

The 90-minute goal is explicitly a systems-level benchmark, not an individual patient target, as patient-specific factors may cause unavoidable delays (diagnostic uncertainty, anatomical challenges, obtaining consent) 1, 3

For interhospital transfers, the first medical contact-to-balloon time goal extends to 120 minutes, though systems should still strive for ≤90 minutes whenever possible 2

Hospitals unable to consistently meet the 90-minute (or 120-minute for transfers) benchmark should use fibrinolytic therapy as their primary reperfusion strategy 2

Common Pitfalls

• Do not interpret 90 minutes as an acceptable target—it represents the maximum tolerable delay, and every minute saved improves survival 1, 3
• Do not delay treatment for extensive diagnostic workup—rapid triage and immediate catheterization laboratory activation are essential 1
• Do not overlook the importance of fibrinolytic therapy when PCI cannot be achieved within goal times—many North American hospitals cannot consistently meet the 90-minute benchmark 1