Tool Predicts Stroke Risk in Patients With Systolic Dysfunction After MI

Randomized trials evaluating treatment options in this population are needed before clinical application of the score, a researcher says.

Tool Predicts Stroke Risk in Patients With Systolic Dysfunction After MI

A novel risk score that incorporates a handful of easily obtained clinical variables appears to be useful for identifying patients with systolic dysfunction after MI who have a heightened risk for stroke in the absence of atrial fibrillation, a new analysis shows.

Derived using pooled data from prior randomized trials, the final model—which included older age, Killip class 3 or 4, estimated glomerular filtration rate 45 mL/min/1.73 m2 or lower, hypertension, and prior stroke—had moderate-to-good discrimination, with a C-index of 0.67.

External validation showed good calibration and discrimination, João Pedro Ferreira, MD, PhD (Regional University Hospital of Nancy, France), and colleagues report in a study published online ahead of the February 20, 2018, issue of the Journal of the American College of Cardiology.

Ferreira told TCTMD that the score, available as an online calculator, can be used to identify individual patients with heart failure and/or systolic dysfunction after MI who are at increased risk for stroke or to select high-risk patients for future trials of preventive strategies.

The tool should not be incorporated into clinical practice until such trials can be performed, he said, because there are no proven approaches to preventing stroke in these types of patients. Routine use of oral anticoagulation is not currently recommended in patients without A-fib, he noted.

“So for now, this can predict stroke and can alert clinicians and trialists to the need to perform a trial on this population, but it does not change clinical practice,” Ferreira said.

In an accompanying editorial, Ronald Freudenberger, MD, MBA (Lehigh Valley Hospital and Health Network Heart Institute, Allentown, PA), says the study “is the only one that identifies post-MI, HF patients without atrial fibrillation and provides a score with good calibration.”

He adds that “this well-constructed risk model is the only such model developed to guide clinicians conducting clinical trials on strategies to enhance the design of future studies in this population.”

High-Risk MI Initiative

To develop the score, the investigators turned to the High-Risk Myocardial Infarction Initiative, which pooled data from four trials that enrolled patients with LV systolic dysfunction, heart failure, or both after MI—CAPRICORN, OPTIMAAL, VALIANT, and EPHESUS. The last trial was used for external validation. The analysis included a total of 22,904 patients who did not have A-fib and were not being treated with oral anticoagulation.

Through a median follow-up of 1.9 years, 2.9% of patients had a stroke.

Patients were divided into six groups based on their risk score, which ranged from 0 to 11 points. Observed 3-year rates of stroke increased across the sextiles:

  • 0-1 points: 1.8%
  • 2 points: 2.9%
  • 3 points: 4.1%
  • 4 points: 5.6%
  • 5 points: 8.3%
  • 6 or more points: 10.9%

Those rates were consistent with expected event rates, indicating good calibration, the researchers say.

Ferreira noted that patients with a score of 3 or higher had a stroke risk similar to that seen in patients with A-fib, suggesting that oral anticoagulation might be useful in this subset of patients without the arrhythmia.

“This really needs to be assessed in an adequately powered trial. Otherwise we cannot subject patients to treatment without robust data,” Ferreira said, adding that the ongoing COMMANDER HF trial might provide some hints. That trial is evaluating whether low-dose rivaroxaban (Xarelto; Bayer/Janssen) will help prevent death, MI, and stroke in patients with heart failure and CAD following an episode of decompensated heart failure.

Sources
  • Ferreira JP, Girerd N, Gregson J, et al. Stroke risk in patients with reduced ejection fraction after myocardial infarction without atrial fibrillation. J Am Coll Cardiol. 2018;71:727-735.

  • Freudenberger RS. Risk scores—medical derivatives. J Am Coll Cardiol. 2018;71:736-738.

Disclosures
  • Ferreira reports having received board membership fees from Novartis and speaker fees from Roche and being a cofounder of CardioRenal.
  • Freudenberger reports no relevant conflicts of interest.

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