The frequency of false-positive cardiac catheterization laboratory activation for suspected ST-segment elevation myocardial infarction (STEMI) is relatively common in community practice, and therefore must be considered regardless of the recent emphasis on rapid door-to-balloon times, according to study published in the Dec. 19 issue of the Journal of the American Medical Association.
David M. Larson, MD, of the Minneapolis Heart Institute Foundation at Abbott Northwestern Hospital, and colleagues, undertook the study to determine the prevalence, etiology and outcomes of false-positive cardiac catheterization laboratory activation in patients with a suspected STEMI.
The study was a prospective registry from a regional system that includes transfer of patients with STEMI from 30 community and rural hospitals with pre-transfer catheterization laboratory activation for percutaneous coronary intervention at a tertiary cardiovascular center in Minnesota. In the study, there were a total of 1,345 patients enrolled from March 2003 to November 2006.
The researchers said that the main outcome measure was the prevalence of false-positive catheterization laboratory activation in patients with suspected STEMI by three criteria: no culprit coronary artery, no significant coronary artery disease (CAD) and negative cardiac biomarker results.
The authors found that of the 1335 patients with suspected STEMI who underwent angiography, 187 (14 percent) had no culprit coronary artery and 127 (9.5 percent) did not have significant CAD. Cardiac biomarker levels were negative in 11.2 percent of the patients. The combination of no culprit artery with negative cardiac biomarker results was present in 9.2 percent of patients. Thirty-day mortality was 2.7 percent without a culprit coronary artery compared to 4.6 percent with a culprit coronary artery.
The researchers noted several sub-populations with a higher prevalence of false-positive cath lab activation. “Women had a higher prevalence of false-positive catheterization laboratory activation based on no culprit artery or no significant CAD, but there was no sex difference when negative cardiac biomarker results were used. Stress cardiomyopathy that occurs predominantly in women accounts for much of this discrepancy,” they wrote.
The authors concluded that the “recent emphasis on rapid door-to-balloon times must also consider the consequences of false-positive catheterization laboratory activation.” The findings suggest that "false-positive catheterization laboratory activation may be another quality metric to monitor for a STEMI program," they concluded.