Abstract 16726: False Positive Coronary Angiography Activation in a Primary Coronary Angioplasty Network: Does Direct Ambulance-based Access Influence The Prevalence Rate?
Purpose: The problem of false positives for ST-segment elevation myocardial infarction (FP-STEMI) is emerging as an unavoidable issue within primary coronary angioplasty (PCI) networks. It is unknown to what extent the type of network organization influences the results and what the minimum and maximum acceptable false positive rates are. We evaluated prevalence, time course and possible determinants of FP-STEMI and, particularly, of false positives for coronary artery disease (FP-CAD) within a large metropolitan PCI network offering both traditional hospital access and direct ambulance-based access with telemedicine facilities allowing pre-hospital transmission of ECG to the cardiologist of the Intensive Care Unit.
Methods: We reviewed all the consecutive admissions to our program between 2004 and 2009. Based on the final hospital diagnosis, patients were classified as: STEMI with culprit lesion; STEMI with absent or minimal coronary lesions; Tako-Tsubo; CAD without culprit lesions; FP-CAD.
Results: 3780 patients with suspected STEMI underwent coronary angiography (mean age 67.7±13.5 years, male gender 70%). Access to the cath lab was ambulance-based in 1175 (31%). STEMI with culprit lesion was present in 3447(91%). The remaining diagnoses were: STEMI with normal coronary artery (2%); CAD without culprit lesion (2.3%); Tako-Tsubo (1%); FP-CAD (3.7%). During the 6-yr period the prevalence of the different final diagnoses did not change. Compared to patients with STEMI and culprit lesion, FP-CAD were younger (60.2 ± 17.9 vs 67.92 ± 13.2 yrs, p= 0.0001), more frequently female (68% vs 32% p= 0.0001) and with anterior ST elevation (82.6% vs 55%, p= 0.0001). FP-CAD rate was not influenced by the type of access (4.2% among ambulance based accesses, 3.4% among hospital based accesses, p= 0.22) or by after hours presentation.
Conclusions: Patients initially diagnosed as STEMI actually represent a heterogeneous population with many final diagnoses. A rate of FP-CAD around 3% is probably inevitable and represents an “acceptable price to pay” to simultaneously guarantee a reasonably low frequency of false negatives. False positive rates this low can be obtained even with an ambulance-based access provided telemedicine facilities are guaranteed
- © 2010 by American Heart Association, Inc.