Vol. 298 No. 23, December 19, 2007     JAMA

"False-Positive" Cardiac Catheterization Laboratory Activation Among
Patients With Suspected ST-Segment Elevation Myocardial Infarction

David M. Larson, MD; Katie M. Menssen, BA; Scott W. Sharkey, MD; Sue
Duval, PhD; Robert S. Schwartz, MD; James Harris, MD; Jeffrey T.
Meland, MD; Barbara T. Unger, RN; Timothy D. Henry, MD

JAMA. 2007;298(23):2754-2760.

Context  Allowing the emergency department physician to activate the
cardiac catheterization laboratory is a key strategy to reduce door-to-
balloon times in patients with ST-segment elevation myocardial
infarction (STEMI). There are limited data on the frequency of "false-
positive" catheterization laboratory activation in patients undergoing
percutaneous coronary intervention for suspected STEMI.

Objective  To determine the prevalence, etiology, and outcomes of
false-positive cardiac catheterization laboratory activation in
patients with a suspected STEMI.

Design, Setting, and Patients  Prospective registry from a regional
system that includes transfer of patients with STEMI from 30 community
and rural hospitals with pretransfer catheterization laboratory
activation for percutaneous coronary intervention at a tertiary
cardiovascular center in Minnesota. A total of 1345 patients were
enrolled from March 2003 to November 2006.

Main Outcome Measure  Prevalence of false-positive catheterization
laboratory activation in patients with suspected STEMI by 3 criteria:
no culprit coronary artery, no significant coronary artery disease,
and negative cardiac biomarker results.

Results  Of the 1335 patients with suspected STEMI who underwent
angiography, 187 (14%; 95% confidence interval [CI], 12.2%-16.0%) had
no culprit coronary artery and 127 (9.5%; 95% CI, 8.0%-11.2%) did not
have significant coronary artery disease. Cardiac biomarker levels
were negative in 11.2% (95% CI, 9.6%-13.0%) of patients. The
combination of no culprit artery with negative cardiac biomarker
results was present in 9.2% (95% CI, 7.7%-10.9%) of patients. Thirty-
day mortality was 2.7% (95% CI, 0.4%-5.0%) without vs 4.6% (95% CI,
3.4%-5.8%) with a culprit coronary artery (P = .33).

Conclusions  The frequency of false-positive cardiac catheterization
laboratory activation for suspected STEMI is relatively common in
community practice, depending on the definition of false-positive.
Recent emphasis on rapid door-to-balloon times must also consider the
consequences of false-positive catheterization laboratory activation.

Author Affiliations: Minneapolis Heart Institute Foundation at Abbott
Northwestern Hospital, Minneapolis, Minnesota (Drs Larson, Sharkey,
Schwartz, and Henry and Mss Menssen and Unger); Department of
Emergency Medicine, Ridgeview Medical Center, Waconia, Minnesota (Dr
Larson); Riverwood Healthcare Center, Aitkin, Minnesota (Dr Harris);
Northfield Hospital, Northfield, Minnesota (Dr Meland); and Division
of Epidemiology and Community Health, University of Minnesota,
Minneapolis (Dr Duval).