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Impact of Direct Cardiovascular Laboratory Activation by Emergency Physicians on False-Positive Activation Rates
Julian Ck Tay1, Liou Wei Lun, Zhong Liang
1Department of Cardiology, National Heart Centre Singapore, Singapore.
Insights
Direct activation of the cardiac catheterization lab (CVL) for ST-elevation myocardial infarction (STEMI) patients improves door-to-balloon (DTB) times without increasing false-positive activations. Factors like female sex, absence of chest pain, and left bundle branch block (LBBB) are associated with false positives.
Area of Science:
- Cardiology
- Emergency Medicine
- Health Services Research
Background:
- Door-to-balloon (DTB) time is a critical determinant of survival for ST-elevation myocardial infarction (STEMI) patients.
- Direct cardiovascular laboratory (CVL) activation by emergency physicians can reduce DTB times.
- Concerns exist regarding the potential for increased false-positive activations with direct CVL activation protocols.
Purpose of the Study:
- To evaluate the rates of false-positive CVL activations before and after the implementation of direct activation by emergency physicians.
- To identify factors associated with false-positive CVL activations in STEMI patients.
Main Methods:
- Retrospective single-center study analyzing emergency CVL activations over a 3-year period before and after July 2007.
- False-positive activations were defined by specific criteria including absence of culprit vessel pathology or presence of chronic total occlusion without biomarker elevation or regional wall abnormalities.
- Coronary angiograms and patient records were reviewed to verify all false-positive cases.
Main Results:
- Out of 1809 subjects, 84 (4.64%) were identified as false-positives.
- The incidence of false-positive activations was 4.1% before and 5.1% after direct activation, a non-significant difference (P = 0.315).
- Multivariate analysis identified female sex (OR: 2.104), absence of chest pain (OR: 5.369), and left bundle branch block (LBBB) as the sole activation indication (OR: 65.691) as significant factors associated with false-positive activations.
Conclusions:
- Direct CVL activation in STEMI management improves DTB times without a significant increase in false-positive activations.
- Identifying factors such as absence of chest pain and LBBB can help optimize STEMI management protocols and reduce unnecessary activations.
Introduction:
Door-to-balloon (DTB) time is critical to ST elevation myocardial infarction (STEMI) patients' survival. Although DTB time is reduced with direct cardiovascular laboratory (CVL) activation by emergency physicians, concerns regarding false-positive activation remain. We evaluate false-positive rates before and after direct CVL activation and factors associated with false-positive activations.
Materials And Methods:
This is a retrospective single centre study of all emergency CVL activation 3 years before and after introduction of direct activation in July 2007. False-positive activation is defined as either: 1) absence of culprit vessel with coronary artery thrombus or ulceration, or 2) presence of chronic total occlusion of culprit vessel, with no cardiac biomarker elevations and no regional wall abnormalities. All false-positive cases were verified by reviewing their coronary angiograms and patient records.
Results:
A total of 1809 subjects were recruited; 84 (4.64%) identified as false-positives. Incidence of false-positive before and after direct activation was 4.1% and 5.1% respectively, which was not significant (P = 0.315). In multivariate logistic regression analysis, factors associated with false-positive were: female (odds ratio (OR): 2.104 [1.247-3.548], P = 0.005), absence of chest pain (OR: 5.369 [3.024-9.531], P <0.0001) and presence of only left bundle branch block (LBBB) as indication for activation (OR: 65.691 [19.870-217.179], P <0.0001).
Conclusion:
Improvement in DTB time with direct CVL activation by emergency physicians is not associated with increased false-positive activations. Factors associated with false-positive, especially lack of chest pain or LBBB, can be taken into account to optimise STEMI management.
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