Marlene Busko

May 17, 2017

NEW ORLEANS, LA — In a study of more than 9000 patients who were hospitalized for non-ST-segment-elevation MI (NSTEMI), those who received early revascularization (within 24 hours) were more likely to survive the first month than those who received late revascularization[1].

Researchers examined 28-day and 1-year mortality after early or late revascularization in low- and high-risk NSTEMI patients who were part of the in the Atherosclerosis Risk in Communities (ARIC) surveillance study from 1987 to 2012.

"In hospitalized NSTEMI patients in the community, early PCI was associated with improved 28-day survival, especially in the high-risk cohort, " Dr Sameer Arora (University of North Carolina, Chapel Hill) reported in a late-breaking clinical-trial session at the Society for Cardiovascular Angiography and Interventions (SCAI) 2017 Scientific Sessions.

"It is not surprising that those patients who had late revascularization were the ones who had higher rates of death," session comoderator Dr Applegate (Wake Forest Baptist Health, Winston-Salem, North Carolina)," commented to heartwire from Medscape.

This study "is a little difficult to interpret," he continued, because the patients who were treated late also presented late. More than half of the patients presented at more than 24 hours from symptom onset, and "and we know that somebody who has an infarction that is going on for more than 24 hours is probably at much higher risk for having all of the morbid complications of an MI, and interventions at that time just may not be useful."

Dr Timothy D Henry (Cedars-Sinai Heart Institute, Los Angeles, CA), a panelist at the session, remarked that "one of the strengths is an opportunity is to see what changes over time, but obviously how we did PCI in 1987 is dramatically different from how you did it in 2012."

Arora replied that the results were similar in the subanalysis of patients who were hospitalized for NSTEMI between 2000 and 2012.

9960 Patients With NSTEMI

Clinical-practice guidelines recommend early revascularization (<24 hours) for high-risk patients with NSTEMI, whereas delayed revascularization (24 to 72 hours) is reasonable for patients with a low risk of clinical events, Arora noted.

However, supporting evidence comes from clinical trials that used composite end points, and there hasn't been a trial showing a difference between mortality after early vs late revascularization, he said.

The researchers identified 9960 patients who were hospitalized with NSTEMI from 1987 to 2012, who were part of the ARIC community surveillance study, which collects data from 21 hospitals in four areas in the US.

They defined early revascularization as revascularization in under 24 hours after symptom onset and late revascularization as revascularization beyond this time.

Patients were classified as low risk if they had a TIMI score of 2 to 4 and high risk if they had a TIMI score of 5 to 7 or cardiogenic shock or ventricular fibrillation.

Two-thirds of the patients (68%) had PCI, 27% had CABG, and 5% (from the early years) received thrombolytics alone.

A third of the patients (3338 patients) received early revascularization.

The mean TIMI score was similar in patients who had early vs late revascularization: 4.4 and 4.3, respectively.

Patients who had early revascularization were slightly younger (mean age 60 vs 62) and more likely to be male (82% vs 80%), white (72% vs 68%), and current smokers (34% vs 29%) and have ST-segment deviation (73% vs 67%). They were less likely to have diabetes (22% vs 28%) or pulmonary edema/CHF (14% vs 22%).

In the overall cohort, 247 patients (2%) died in the hospital; 310 patients (3%) died within 28 days of hospital admission; and 569 patients (6%) died within 1 year of hospital admission.

A little more than half of the patients (5390 patients; 54%) were classified as low risk.

"As expected," high-risk patients had a higher mortality rate, and mortality was lowest after PCI, followed by CABG, followed by thrombolytic therapy, said Arora.

Early revascularization was associated a lower risk of dying at 28 days after revascularization for low-risk patients (OR 0.13, 95% CI 0.02–0.93; P=0.04) and high-risk patients (OR 0.62, 95% CI 0.40–0.94; P=0.04), after adjustment for multiple confounders.

The analysis was repeated in 2376 patients who had early PCI and 4370 patients who had late PCI.

High-risk patients and those who presented within 6 hours or within 24 hours of symptom onset had significantly lower 28-day mortality if they received early vs late PCI.

However, there was no advantage in the low-risk group, but this was likely due to the small number of deaths in this group.

There were also no significant between-group differences in 1-year mortality.

The findings were similar in a further subanalysis of patients who were hospitalized with NSTEMI from 2000 to 2012 and had PCI.

Study limitations include the use of symptom onset as opposed to time of admission to the hospital and revascularization rather than angiography, based on the available data, and there may have been other confounders that were not accounted for, Arora acknowledged.

"It's puzzling" that the survival benefit with early revascularization was seen at 28 days but not at 1 year," Henry observed.

More study is needed, Arora agreed. "We recommend a large clinical trial investigating early vs late revascularization in patients with low to intermediate risk of clinical events," he concluded.

Arora had no relevant financial relationships. Applegate disclosed that he is a consultant for Abbott.

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