Immediate Versus Delayed Invasive Intervention for Non-STEMI Patients: The RIDDLE-NSTEMI Study

Area of Science:

• Cardiology
• Interventional Cardiology
• Acute Coronary Syndromes

Background:

• Conflicting evidence exists regarding the optimal timing of invasive intervention for non-ST-segment myocardial infarction (NSTEMI).
• Previous studies on acute coronary syndromes without ST-segment elevation have yielded heterogeneous results.

Purpose of the Study:

• To evaluate the clinical impact of immediate versus delayed invasive strategies in patients diagnosed with NSTEMI.
• To compare the rates of death or new myocardial infarction (MI) at 30-day follow-up between the two intervention groups.

Main Methods:

• A randomized controlled trial involving 323 NSTEMI patients.
• Patients were allocated to either an immediate-intervention group (angiography <2 hours) or a delayed-intervention group (angiography 2-72 hours).
• The primary endpoint was the composite of death or new MI within 30 days.

Main Results:

• Immediate intervention (median 1.4h) showed significantly lower rates of death or new MI at 30 days (4.3% vs. 13%, p=0.008) and 1 year (6.8% vs. 18.8%, p=0.002).
• The benefit was largely driven by a reduction in new MIs occurring before catheterization.
• Combined endpoints including recurrent ischemia were also significantly lower in the immediate intervention group at both time points.

Conclusions:

• An immediate invasive strategy in NSTEMI patients is superior to a delayed approach.
• This strategy leads to reduced rates of death or new MI at both early and midterm follow-up.
• The primary benefit stems from preventing pre-catheterization myocardial infarctions.