RESUMO
Decision-making in acute chest pain remains challenging despite normal (below ninety-ninth percentile) high-sensitivity troponin (hs-cTn). Some studies suggest that undetectable hs-cTn, far below the ninety-ninth percentile, might rule out acute coronary syndrome. We investigated clinical data in comparison to undetectable hs-cTnT. The study comprised 682 patients (November 2010 to September 2011) presenting at the emergency department with chest pain and normal hs-cTnT (<14 ng/l). The main end point was major adverse cardiac events (MACE: death, myocardial infarction, readmission for unstable angina, or revascularization) at a 4-year median follow-up; secondary end point was 30-day MACE. A clinical score was built by assigning points according to hazard ratios of the independent predictive variables: 1 point (male and effort-related pain) and 2 points (recurrent pain and prior ischemic heart disease). The negative predictive values of the clinical score and undetectable hs-cTnT (<5 ng/l), were tested. A total of 72 (10.6%) patients suffered long-term MACE. The C-statistics of the clinical score for long-term (0.75) and 30-day (0.88) MACE were higher than with the TIMI(Thrombolysis In Myocardial Infarction) risk (0.68, 0.77) or GRACE(Global Registry of Acute Coronary Events) (0.50, 0.47) scores. Likewise, the negative predictive values of score = 0 (97.5%, 100%) and ≤1 point (95.9%, 100%) were higher than using undetectable hs-cTnT (91.9%, 98.1%). Both clinical scores of 0 and ≤1 better classified patients at risk of MACE (p = 0.0001, log-rank test) than hs-cTnT <5 ng/l (p = 0.06). In conclusion, clinical data can guide decision-making and perform at least equally well as undetectable hs-cTnT, in patients presenting at the emergency department with chest pain and normal hs-cTnT.
