Optimal timing of intervention in non-ST-segment elevation acute coronary syndromes: insights from the CRUSADE (Can...

Area of Science:

• Cardiology
• Interventional Cardiology
• Health Services Research

Background:

• Routine invasive strategies improve outcomes for unstable angina (UA) and non-ST-segment elevation myocardial infarction (NSTEMI).
• Optimal timing for invasive procedures in these acute coronary syndromes remains debated.
• Weekend hospital admissions may impact timely access to care.

Purpose of the Study:

• To investigate the impact of hospital presentation timing (weekday vs. weekend) on acute outcomes for UA and NSTEMI patients.
• To assess the association between delayed cardiac catheterization and revascularization and adverse in-hospital events.
• To utilize weekend presentation as an instrumental variable for evaluating the optimal timing of invasive management.

Main Methods:

• Retrospective analysis of 56,352 UA/NSTEMI patients from the CRUSADE initiative (2001-2003).
• Instrumental variable analysis using weekend presentation as a proxy for delayed invasive procedures.
• Comparison of outcomes (death, reinfarction, stroke, heart failure) between weekend and weekday admissions.
• Risk adjustment and alternative definitions were used to validate findings.

Main Results:

• Weekend admissions experienced significantly longer median times to cardiac catheterization (46.3 vs. 23.4 hours).
• Despite delays, weekend patients showed no significant increase in in-hospital death, recurrent MI, or composite adverse events.
• Instrumental variable analysis revealed no significant benefit from early catheterization, but a trend towards reduced mortality within 12 hours was noted.

Conclusions:

• Weekend presentation is linked to delayed invasive management for UA/NSTEMI but does not elevate adverse events with contemporary therapy.
• Weekend status serves as a valid instrumental variable for studying invasive management timing in acute coronary syndromes.
• While early catheterization (within 12 hours) showed a non-significant trend toward reduced mortality, overall early intervention did not demonstrate significant benefit.