Rule-Out yield of the European society of cardiology 0/1-Hour troponin protocol in frail and non-frail octogenarians

Objectives To evaluate the rule-out yield of the European Society of Cardiology (ESC) 0/1-h high-sensitivity cardiac troponin I (hs-cTnI) algorithm for 30-day major adverse cardiac events (MACE) in emergency department (ED) patients aged ≥ 80 years, and explore whether frailty modifies performance. Methods This retrospective single-center cohort study included patients aged ≥ 80 undergoing 0/1-h hs-cTnI sampling for suspected acute coronary syndrome. Frailty was defined using the Clinical Frailty Scale (≥ 5). The prespecified primary outcome was the 30-day MACE miss rate in the rule-out stratum against a 1% threshold. Results Of 1,136 screened encounters, 800 were analyzed (median age 83 years; 56.9% female); 312 (39.0%) were frail. Blinded re-abstraction of 80 records yielded kappa 0.82 (0.71–0.93) for frailty and agreement ≥ 0.71 across variables. The algorithm classified 120 patients (15.0%) as rule-out (prespecified target, 236); two had 30-day MACE (miss rate 1.7%; wide 95% Wilson CI, 0.5%-5.9%), an imprecise estimate whose upper bound exceeds the 1% threshold. A post hoc bounding analysis counting all 11 rule-out patients with incomplete nonfatal ascertainment as events raised the upper bound to 10.8% (6.4%-17.7%). Sensitivity was 99.0% and negative predictive value 98.3%. In prespecified exploratory analysis, no statistically significant independent association was observed between frailty and 30-day MACE (average marginal effect + 1.03 percentage points; 95% CI, -5.05 to + 7.20; p = 0.744). Conclusions The ESC algorithm ruled out only 15% of octogenarians, potentially reflecting baseline age- and renal-related troponin elevations. Limited rule-out sample size, wide confidence intervals, and incomplete follow-up prevent a definitive safety conclusion.