Decision making and prognosis of a cohort of patients with chest pain and cardiac troponin flat curve

Introduction Acute myocardial injury is defined by cardiac troponin (cTn) levels above the 99th percentile with a dynamic rise/fall pattern (Δ), usually suggesting acute coronary syndrome (ACS) when associated with compatible symptoms. However, patients presenting with chest pain, elevated cTn and a Δ<20% (flat curve) represent a diagnostic grey zone, as current guidelines do not clearly associate this pattern with ACS. We aimed to analyze clinical characteristics, management strategies and six-month outcomes of these patients according to initial management: admission to cardiology, admission to another department or discharge from the emergency department. Methods We prospectively analyzed 753 consecutive patients with suspected ACS and a cTn-flat-curve (Δ<20% in two high-sensitivity cTn-T determinations at 0 and 3 hours) between May 2023 and January 2026. Six-month follow-up was available in 614 patients (median 185 days). Results Mean age was 75.7±11.9 years and 63.3% were male. Management differed significantly across groups. As detailed in Table 1 and Table 2, patients admitted to cardiology were younger (71.6±12.7 years), more frequently male, and more often presented with high-probability ischemic chest pain, dynamic ECG changes and new wall motion abnormalities. They underwent coronary angiography in 90.8% of cases and were diagnosed with ACS in 78.7%. Patients admitted to other departments were older (80.8±9.7 years), had a higher prevalence of atrial fibrillation, heart failure, chronic kidney disease and oncological disease, and more frequently presented with low-probability symptoms. This group showed the highest six-month mortality (26.5%) and MACE rate (32.6%). Discharged patients had lower troponin levels, fewer high-risk clinical findings and low six-month mortality (3.7%), supporting the safety of discharge when guided by comprehensive clinical assessment. Conclusions In patients with suspected ACS and a cTn-flat-curve, management decisions reflected distinct clinical profiles and were strongly associated with outcomes. A flat troponin pattern did not exclude ACS, and careful integration of clinical, ECG and echocardiographic findings allowed appropriate risk stratification and safe discharge in selected patients.