BACC: Protocol for Rapid Diagnosis of Myocardial Infraction

The 1-hour algorithm using high-sensitivity troponin measurement for rapid diagnosis of AMI is safe.

To carry out the BACC study (Biomarkers in Acute Cardiovascular Care) the effects of the troponin assay at 1 hour were compared to its effects after the 3 hours recommended by the ESC guidelines in 1.045 patients presenting with acute chest pain (mean age 65, 64.9% male). In addition, they analyzed a cut off value of 6 ng/L, far lower than the recommended 27 ng/L 99th percentile value for the ultrasensitive troponin assay (Elecsys; Roche Diagnostics) and the high sensitivity troponin I assay (STAT hs Tn I; Abbott Diagnostics).

The use of ultrasensitive cTn I with a ≤ 6 ng/L cutoff ruled out STEMI in 402 patients after an hour, and no differences were observed when compared to discharge at 3 hours. Moreover, compared to the 6 ng/L, the 27 ng/L cutoff resulted in a lower negative predictive value (NPV), regardless testing time (P < .005 for both) and also resulted in lower sensitivity.

An algorithm to rule out NSTEMI should include the ultrasensitive cTn I > 6 ng/L after one hour with a 12 ng/L delta compared to admission values (positive predictive value PPV 87.1%; specificity 98.0%).

These algorithms were verified against 4.009 patients from the European cohort (NPV 99.2% rule out, PPV 80.4% rule in) that also used a 1 hour algorithm, and against the Australian cohort (NPV 99.7% rule out; VPP 81.5% rule in).

During a 183 day follow up, only 3 patients died (0.79%) in the rule out < 6 ng/L group. However, 12 had died (1.73%) using the 27 ng/L cut off value (P < .05).

Westermann D.