Disease Outside of Culprit Artery Tied to Greater Short-term Mortality After STEMI

Obstructive non–infarct-related artery (non-IRA) coronary disease is associated with an increase in 30-day mortality in patients with ST-segment elevation myocardial infarction (STEMI), according to a retrospective study published in the November 19, 2014, issue of the Journal of the American Medical Association.

The finding, which was originally presented at the American College of Cardiology/i2 Scientific Session earlier this year, raises questions about the usefulness of non-IRA interventions in this setting.

“However, we cannot address whether the presence of non-IRA disease has direct causality for mortality or if it functions as a marker of more severe coronary atherosclerosis and combined high-risk clinical comorbidity,” Manesh R. Patel, MD, of Duke University Medical Center (Durham, NC), and colleagues write. “In addition, our study does not delineate the exact mechanism linking non-IRA disease and mortality in patients with STEMI.”


 
Methods
The researchers pooled data from a convenience sample of 8 international randomized STEMI trials published from 1993 to 2007 with databases maintained at the Duke Clinical Research Institute; follow-up ranged from 1 month to 1 year. Analysis was restricted to 28,282 patients who had valid angiographic information available. The infarct was located in the LAD in 41.2% of patients, the LCX in 12.4%, and the RCA in 46.4%.
Slightly more than half of patients (52.8%) had obstructive non-IRA disease; it involved 1 vessel in 29.6% and 2 vessels in 18.8%. The extent and location of obstructive non-IRA disease were unrelated to the location of the infarct.

After multivariate adjustment, patients with non-IRA disease were more likely to die within 30 days compared with those without non-IRA disease (3.3% vs 1.9%; P < .001), with even higher risks of mortality in patients with a greater extent of disease. The findings were consistent in both thrombolytic trials and PCI trials when examined separately.

Additionally, mortality was increased in patients with non-IRA disease regardless of whether it involved total occlusion, but the risk was enhanced in those with complete obstruction.

At 1 year, non-IRA disease also was associated with higher mortality (5.4% vs 3.5%), according to data from 3 trials (n = 23,014).

To validate the findings, the researchers used data from 18,217 patients included in the Korea Acute MI Registry (KAMIR) and 1,812 patients included in the Duke Databank for Cardiovascular Disease. Non-IRA disease was associated with greater risks of mortality at both 30 days and 1 year in KAMIR but only at 1 year in the Duke database.

“The lack of confirmatory validation regarding 30-day mortality in the Duke registry might be due either to limited power for a short-term mortality effect of non-IRA disease or differential care patterns present at a single center,” the authors say.

Enough Data to Recommend Treatment of Non-IRA Disease?

Dr. Patel and colleagues point out that there is uncertainty about how to manage non-IRA disease in STEMI patients because no large trial has definitively addressed the question. Smaller studies comparing aggressive vs more conservative approaches to non-IRA disease have yielded mixed results, although the recent PRAMI and CvLPRIT trials have provided support for more complete revascularization.

There was no information about how non-IRA disease was treated in this study, which is also limited by potential residual confounding and selection bias, variability across the included studies, and changes in STEMI treatment over time, the researchers say.

“This clinical issue warrants further investigation to determine the best clinical management, which would ideally be confirmed through large, randomized clinical trials with long-term follow-up,” they write.

J.P. Reilly, MD, of Ochsner Medical Center (New Orleans, LA), told TCTMD in a telephone interview that the study “does corroborate intuitively what we would expect” but that it “cannot create an argument that we definitely should intervene on these non–infarct-related artery lesions. It notes the association between mortality and having these lesions but doesn’t really tell us what to do about it.”

Even PRAMI and CvLPRIT probably do not provide enough evidence to recommend intervening on non-IRA lesions, but they might be enough to at least remove the class III recommendation against complete revascularization in primary PCI, added Dr. Reilly, who is chair of the public relations committee for the Society for Cardiovascular Angiography and Interventions.

 

Source:

Park D-W, Clare RM, Schulte PJ, et al. Extent, location, and clinical significance of non–infarct-related coronary artery disease among patients with ST-elevation myocardial infarction. JAMA. 2014;312:2019-2027.

  • Dr. Patel reports serving as a consultant to Bayer; receiving grant support from the Agency for Healthcare Quality, AstraZeneca, GlaxoSmithKline, Johnson & Johnson, and the National Heart, Lung, and Blood Institute; and serving on advisory boards for AstraZeneca, Genzyme, Janssen, and Otsuka.
  • Dr. Reilly reports no relevant conflicts of interest.

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Todd Neale is the Associate News Editor for TCTMD and a Senior Medical Journalist. He got his start in journalism at …

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Disclosures
  • This study was supported in part by the John Bush Simson Fund. The statistical portion of the manuscript was funded by the Duke Clinical Research Institute.

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