Long cardiac troponin T in myocardial infarction: a promising diagnostic tool, a precision imperative

This commentary refers to ‘Long forms of cardiac troponin T for myocardial infarction diagnosis: the SuperTROPO study’, by K. Teppo et al., https://doi.org/10.1093/eurheartj/ehaf975 and the discussion piece Long cardiac troponin T in myocardial infarction: the SuperTROPO study is a promising starting point' by K. Teppo et al., https://doi.org/10.1093/eurheartj/ehag332. Teppo et al.1’s SuperTROPO study makes a pivotal contribution to myocardial infarction (MI) diagnostics by demonstrating that long cardiac troponin T (long cTnT) outperforms total cTnT in distinguishing MI, particularly type 1 MI, among emergency department patients with elevated troponin levels.1 This work addresses the long-standing challenge of over diagnosis driven by conventional high-sensitivity troponin assays’ limited specificity. Critical gaps remain, including insufficient prognostic data, unclear utility in combined biomarker models, and lack of standardized thresholds for diverse settings, all hindering its full translation into precision care. First, we propose integrating long cTnT with other cardiovascular biomarkers to develop a multi-marker diagnostic-prognostic model. While long cTnT excels at distinguishing MI from non-MI troponin elevations, its performance in differentiating MI from other acute cardiac conditions, such as myocarditis and Takotsubo syndrome, remains unclear.2 Combining long cTnT with biomarkers reflecting distinct pathophysiological pathways, such as NT-proBNP for heart failure, high-sensitivity C-reactive protein for inflammation, or myeloperoxidase for atherothrombosis, could enhance aetiological discrimination and risk stratification. Li et al.3 recently showed that multi-marker models targeting troponin fragments and complexes improve differential diagnosis of myocardial injury, suggesting a similar approach could maximize long cTnT’s clinical utility. Second, long-term prognostic validation is urgently needed. The current study focuses solely on diagnostic accuracy, and understanding whether long cTnT levels or the long cTnT/total cTnT ratio predict post-MI outcomes, such as recurrent infarction and cardiovascular death, would transform it from a diagnostic tool to a guidance tool for personalized treatment intensity.4 Third, standardized thresholds for diverse clinical scenarios are essential. The study’s single threshold of 8.8 ng/L may not apply to community healthcare settings or patients with comorbidities, such as advanced kidney disease, where clinical needs and baseline troponin levels vary. Multi-centre studies tailored to specific populations and settings could establish scenario-specific thresholds, ensuring broader applicability. Such standardization aligns with current clinical guidelines that emphasize context-adapted biomarker interpretation.5