Chest pain and cardiac troponin flat curve: percentage of acute coronary syndrome and prognosis of a cohort of patients

Introduction Acute myocardial injury is defined by cardiac troponin (cTn) levels exceeding the 99th percentile upper reference limit, with dynamic rise/fall pattern (Δ), often suggesting acute coronary syndrome (ACS). However, some patients present with chest pain and elevated cTn but with a Δ<20% (flat curve): they are a diagnostic challenge because according to current guidelines this pattern is not related to an ACS. Aim of this study is to analyze the prognosis of these patients based on their management: admission or discharge from the emergengy department (ED) as well as the number of ACS finally found. Methods We prospectively analyzed data of 664 patients with suspected ACS and a cTn flat curve (Δ<20% in two high-sensitivity cTn-T determinations at 0/3 hours) from May 2023 to September 2025. A six-month follow-up was completed in 547 patients, with a median follow-up of 185 days. Prognosis was based on major cardiovascular events (MACE: mortality, infarction, revascularization, stroke, or vascular surgery) and non-cardiovascular events. Results in this group of patients mean age was 75.8±11.8 years, 62.8% males; 199 patients were admitted to Cardiology, 138 to other departments, and 327 were discharged directly from the ED. One hundred and fifty eight patients (23.8%) were finally diagnosed with ACS, (only 14.5% of them with non-invasive tests). Patients admitted to non-cardiology departments had more MACE, more mortality and more non-cardiovascular events. Global mortality was mostly due to non-cardiac causes and cardiac mortality was mainly due to heart failure in all three groups. These results are shown in Table 1. Kaplan-Meier curves (Figure 1) showed significant survival differences between admitted and discharged patients. Conclusions - Cardiac troponin flat curve is frequently found in patients with chest pain. Its presence does not rule out the ocurrence of an ACS. - In these patients, event-free survival was low, particularly in those admitted to non-cardiology departments, where mortality was high and mainly due to non-cardiovascular origin. Discharged patients were not event-free but had low cardiac mortality rates. - Patients with other conditions different than ACS and cTn flat curve must be consider as high risk patients, given the large number of events observed during follow-up.