All Dressed Up And No Place To Go: False-Positive Activation Of The Cath Lab For Primary PCI

Primary PCI is widely recognized as the best early option for patients with  ST-segment elevation myocardial infarction (STEMI). However, efforts to deliver primary PCI to the broadest possible population inevitably result in an increased number of false-positive activations of the cardiac catheterization laboratory. Now, a new studypublished in the Archives of Internal Medicine finds that the rate of false-positive activations is higher than expected.

James McCabe and colleagues analyzed data from 411 STEMI activations at two primary PCI centers. More than one-third — 36% — were judged to be false-positive. Patients with high BMIs or with chest pain or pressure at presentation were less likely to have a false-positive activation. The following factors were independently associated with an increased risk for a false-positive STEMI activation:

  • Left ventricular hypertrophy on ECG: adjusted odds ratio (AOR) 3.15, CI 1.55- 6.40, p=0.001
  • History of coronary disease: AOR 1.93, CI 1.04-3.59, p=0.04
  • History of  illicit drug abuse: AOR 2.67, CI 1.13-6.26, p=0.02
The authors conclude:
While a certain percentage of false-positive STEMI activations are essential to ensuring adequate diagnostic sensitivity, the point of equipoise between necessary diagnostic sensitivity and patient safety requires further investigation, particularly in light of increasing resource limitations.
In an accompanying commentary, Fouad Bachour and Richard Asinger note that the higher-than-expected rate of false-positives in the study may be partly due to “the variability of definitions.” They recommend that primary PCI programs adopt “a systematic protocol for the diagnosis and emergent treatment of STEMI including pivotal medical history for comorbid features, patient preference, continuous review of clinical experience, and direct feedback.” They suggest that an “acceptable rate of inappropriate activations … is probably in the 15% to 20% range.”
     —CardioExchange News

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