Early Invasive NSTEMI Strategy: Fewer MIs in Small Trial

Pam Harrison

January 26, 2016

BELGRADE, SERBIA — "Immediate" bested "delayed" with respect to timing of invasive management of stabilized non-ST-segment-elevation MI (NSTEMI) in a small single-center randomized trial[1].

The strategy of early coronary angiography with possible PCI, initiated within 2 hours, was associated with a 68% reduction in 30-day risk of death or new MI vs a delay of up to 72 hours, with the difference (P=0.008) driven by fewer new MIs.

The risk reduction for the composite primary end point was essentially the same at 1 year, observe investigators in their January 6, 2016 publication of the RIDDLE-NSTEMI trial in JACC: Cardiovascular Interventions.

If the findings are confirmed in larger trials, "the currently recommended risk-based, stratified approach, with earlier intervention in patients with more risk factors, may be shifted toward a primary-PCI-like approach with early invasive intervention for all NSTEMI patients," senior author Dr Goran Stankovic (Clinical Center of Serbia, Belgrade) told heartwire from Medscape in written correspondence.

The trial randomized 162 patients with NSTEMI to immediate intervention and 161 to delayed intervention. Patients were eligible for the study if they experienced chest pain with onset no more than 24 hours prior to admission.

Patients assigned to the immediate-intervention group received a loading dose of dual-antiplatelet therapy consisting of aspirin 300 mg plus clopidogrel 600 mg, whereas the delayed-intervention group received both drugs at 300 mg. Both groups then received aspirin at 100 mg/day and clopidogrel at 75 mg/day.

Median time from randomization to angiography was 1.4 hours in the immediate-intervention group and 61 hours in the delayed-intervention group (P<0.001). PCI was performed more often in the immediate-intervention group (78.4% vs 65.0%).

At 30 days, the rate of death or new MI was 4.3% in the immediate-intervention group vs 13% in the delayed-intervention group, for an adjusted hazard ratio (HR) of 0.32 (P=0.0008). Mortality at 30 days was the same in both groups at 3.1%.

At 1 year, the cumulative composite rate of death and new MI was again significantly lower in the immediate-intervention group at 6.8% compared with 18.8% in the delayed-intervention group (P=0.002). The 1-year cumulative rate of death, new MI, or recurrent ischemia, a secondary end point, was also reduced with immediate invasive intervention, at 15.4%, vs 33.1% in the delayed-intervention group (P<0.001). Major bleeding rates were low in both groups, with no significant differences at 30 days or 1 year.

"To the best of our knowledge, this is the first randomized trial to include only NSTEMI patients while having a clinical primary end point," state the authors, led by Dr Aleksandra Milosevic (Clinical Center of Serbia). "Future studies with standardized protocols that include clinically oriented definition of periprocedural MI, larger sample size, and longer-term follow-up are needed to assess the true effect of immediate intervention in NSTEMI patients."

Such a study is currently under way, they write. The Acute Versus Subacute Angioplasty in Patients With Non-ST-Elevation Myocardial Infarction (NONSTEMI) trial will have an estimated enrollment of 4500 patients; completion of the primary data collection is estimated for 2017.

The authors report no relevant financial relationships.


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