DEFINING THE ERROR RATE: CARDIAC CATHETERIZATION LABORATORY FALSE ACTIVATIONS

Background:  Activation of the cardiac catheterization laboratory (CCL) by emergency physicians (EP’s) has been shown to decrease Door-to-Balloon (D2B) time in patients with ST Elevation Myocardial Infarction (STEMI).  Concern has been raised about catheterization laboratory false activations (CLFA) and its associated costs to the healthcare system.  There are a number of CLFA definitions used in the medical literature.  Historic use of an identifiable culprit lesion to define CLFA does not adequately reflect the presence of a false activation given the current time pressures for CCL activation.  Defining the CLFA rate based on the electrocardiographic definition of STEMI and immediate catheterization may prove more relevant and useful for analyzing and improving the error rate.  Our study compared the false activation rate of two definitions.

Methods:  Design: IRB approved retrospective cohort review of all patients who presented to the Emergency Department with EP CCL activation at a single academic medical center from June 2008 through December 2010. Exclusion criteria: refusal of procedure or death prior to completion of procedure. Demographics and catheterization results were determined for each patient. The definitions of CLFA compared were 1) CCL activation without immediate catheterization; 2) CCL activation without identifiable culprit lesion.  Descriptive statistics and confidence intervals are reported using Microsoft Excel and SPSS 17.0. Chi –square analysis and t-test were used to compare the groups. 

Results:  210 activations were reviewed, and 15 were excluded. No STEMIs were missed during the study period.  Of 195 cases included, the mean age was 64.8 years with a standard deviation of 15.0 and 72% [CI 65-78] were male.  155 patients 80% [CI 74-85] were taken to the CCL.  Of 153 undergoing immediate catheterization, 120 patients 80% [CI 73-86] had culprit lesions identified.  Two patients for which the EP activated the CCL but did not undergo immediate catheterization ultimately had culprit lesions identified.  There was no significant difference in age or gender between groups. (p=0.78, 0.93)

Conclusion: Catheterization laboratory false activations are not uncommon.  While several definitions of CLFA exist, we propose a more useful definition of CCL activation with immediate catheterization as opposed to the historic definition that includes a culprit lesion.  Efforts to reduce CLFAs must be weighed against potential reductions in both sensitivity of EP identification of STEMI as well as potential impact on D2B time.  Efforts to identify the root cause of these CLFAs need further study using a common and relevant definition.