High-Sensitivity vs Conventional Troponin Cutoffs for Risk Stratification in Patients With Acute Pulmonary Embolism

Importance High-sensitivity troponin tests can detect even milder cardiac troponin elevations in plasma, beyond the threshold of conventional troponin tests. Whether detection of low-grade cardiac troponin elevation is associated with outcomes of patients with hemodynamically stable pulmonary embolism (PE) and helps with risk stratification is unknown. Objective To determine the association between high-sensitivity cardiac troponin I (hs-cTnI) compared with conventional cardiac troponin I (cTnI) and PE risk designations according to the European Society of Cardiology (ESC) 2019 classification scheme and clinical outcomes in patients with hemodynamically stable PE. Design, Setting, and Participants This is a post hoc analysis of data from the prospective Prognostic Value of Computed Tomography (PROTECT) multicenter cohort study enrolling patients from 12 hospital emergency departments in Spain. In this analysis, cTnI and hs-cTnI were compared with respect to ESC risk designation, and the association between troponin values and a complicated course after PE diagnosis was evaluated. Of 848 patients enrolled in PROTECT, 834 (98.3%) had hsTnI and cTnI values available and were included in the present analysis. Data were analyzed from May to December 2022. Exposures Troponin blood testing with cTnI (threshold of >0.05 ng/mL) vs hs-cTnI (threshold of >0.029 ng/mL) assays at the time of PE diagnosis. Main Outcomes Complicated course, defined as hemodynamic collapse, recurrent PE, or all-cause death, within 30 days after PE. Results Of 834 patients (mean [SEM] age, 67.5 [0.6] years; 424 [50.8%] female), 139 (16.7%) had elevated cTnI and 264 (31.7%) elevated hs-TnI, respectively. During follow-up, 62 patients (7.4%; 95% CI, 5.7-9.4) had a complicated course. Analyzing troponin elevation as a binary variable, elevated cTnI (odds ratio [OR], 2.84; 95% CI, 1.62-4.98) but not hs-cTnI (OR, 1.12; 95% CI, 0.65-1.93) was associated with increased odds of a complicated course. Of 125 patients who had elevated hs-cTnI but normal cTnI, none (0; 95% CI, 0.0-2.9) developed a complicated course. Using the 2019 ESC risk stratification scheme, hs-TnI classified fewer patients as low risk compared with cTnI. Among 78 patients designated as ESC low risk when using cTnI but not with hsTnI, none (0; 95% CI, 0.0-4.6) had a complicated course. Conclusions and Relevance In this study of patients with hemodynamically stable PE, hs-cTnI identified modest elevations in cardiac troponin levels. However, the results did not provide additive clinical value compared with cTnI. These findings suggest that use of hs-cTnI may result in overestimation of the risk in patients with stable PE.