The aim of this study is to compare a new improved point of care cardiac troponin assay (new POC-cTnI) with 1. its predecessor (old POC-cTnI) and 2. a high sensitivity assay (hs-cTnI) for the diagnosis of acute myocardial infarction (AMI) and for major adverse cardiac events (MACE) by 30 days.
This is a single centre observational study, set in Christchurch Hospital, New Zealand. Patients presenting to the emergency department with non-traumatic chest pain underwent blood sampling at 0 h and 2 h post presentation for analysis with the 3 cTnI assays for the outcome of AMI and for analysis using an accelerated diagnostic protocol (ADP-normal 2 h troponins, normal electrocardiograms and Thrombolysis In Myocardial Infarction (TIMI) score of 0 or = 1) for 30 day MACE.
Of 962 patients, 220 (22.9 ) had AMI. Old POC-cTnI was least sensitive at 70.0 (65.4?73.9 ) by 2 h (p <0.001). New POC-cTnI, sensitivity 93.6 (89.9?96.2 ) had similar sensitivity to hs-cTnI, sensitivity 95.0 (91.5?97.3 ) (p = 0.508). There were 231 (24.0 ) patients with 30 day MACE. When used as part of the ADP, all assays had 100 (98.0?100 ) sensitivity using TIMI = 0. Sensitivities of new POC-cTnI ADP, 98.3 (95.4?99.4 ), old POC-cTnI, 96.5 (93.2?98.4 ) and hs-cTnI, 98.7 (96.0?99.7 ) were similar (p = 0.063?0.375) using TIMI = 1.
A new POC-cTnI has improved sensitivity for AMI and MACE compared with its predecessor and comparable sensitivity to a high sensitivity assay. Now that sensitivities of the POC assay are improved, the new assay may be a useful alternative to central laboratory assays when rapid turn-around times are not possible.
ADAPT, 2-hour Accelerated Diagnostic protocol to Assess Patients with chest pain symptoms using contemporary Troponins; ADP, accelerated diagnostic protocol; AMI, acute myocardial infarction; ASPECT, Asia Pacific Evaluation of Chest Pain Trial; ED, Emergency Department; (hs)-cTn, (high sensitivity) cardiac troponin; MACE, major adverse cardiac events; POC, point of care; TIMI, Thrombolysis In Myocardial Infarction