LAUSR

Introduction Point of care test has many advantages including access and time to result. The major disadvantage in POC for cardiac troponin is the lack of high-sensitivity assays, matching the analytical performance of central laboratory testing. The HEART score can easily be applied in the Emergency Department using data collected as part of routine evaluation of the patient. The objective of this study, was to re-evaluate the HEART score, using a score of 0–2 as low risk, accounting for the poorer analytical sensitivity of POC troponin assays. Methods This is a sub-study of the Bedside Evaluation of Troponin (BEST) Study. We recruited patients presenting to the ED with suspected Acute Coronary Syndromes. Blood for POC TnI (LoD 20 ng/L; 99th Percentile 80 ng/L and Functional Sensitivity, CV<10%, 100ng/L) was drawn at presentation and 3 hours later. The HEART Score was calculated as published using the LoD, 99th percentile and functional sensitivity as the upper limit of normal for troponin. A HEART score of 0–2 was taken as low risk (BEST-HEART score). All patients underwent central laboratory testing over 3–12 hours. We also combined the BEST-HEART score with a normal troponin at baseline and 3 hours using 20ng/L, 80ng/L and 100ng/L as the ULN. The primary outcome was a diagnosis of ACS, defined as acute myocardial infarction during the initial presentation or major adverse cardiac event (MACE) within 30 days, including all-cause mortality, incident MI and coronary revascularisation. The diagnosis of AMI was based on the Third Universal Definition (table 1). Abstract 153 Table 1 Results 614 patients (238 (38.2%) female and 385 (61.8%) male were included. ACS was reported in 86 (13.8%). The AUC for the HEART score was 0.75 (100ng/L); 0.80 (80ng/L) and 0.84 (20ng/L), although compared to functional sensitivity this did not reach statistical significance (p=0.97 & 0.17 respectively) (figure 1). A low risk BEST-HEART score using 20ng/L (LoD) as the ULN had the greatest sensitivity (96.5%) and NPV (98.5%). Using the BEST-HEART score alone would have a probability of missed ACS of 1.5%. Combining a low risk BEST- HEART score with a normal troponin (ULN 20 ng/L) over 3 hours improved the sensitivity (100%) and NPV (100%), ruling out 164 (30.1%) patients. Abstract 153 Figure 1 Conclusion The BEST-HEART score had improved diagnostic accuracy compared to the traditional HEART score using a contemporary POC troponin assay. While the BEST-HEART score has insufficient sensitivity to exclude ACS, it may be used where access to central laboratory testing is not widely available if clinicians will accept the small risk of missed ACS. The addition of normal troponin over 3 hours improves the sensitivity and NPV, but requires an additional delay for follow up testing. This protocol should be prospectively validated prior to clinical use. Conflict of Interest None