Comparison of Characteristics among Suspected ACS Patients by Normal and Elevated Hs-Troponin Levels

Abstract

Background: Acute coronary syndrome (ACS) is a life-threatening condition that requires prompt diagnosis and treatment. However, some patients with ACS may have normal levels of high-sensitivity cardiac troponin (hs-cTn), a biomarker of myocardial injury, at presentation. This study aimed to compare the characteristics and outcomes of ACS patients with normal and elevated hs-cTn levels using different assays and thresholds. Material & Methods: This 2-year retrospective observational study was conducted in Bangladesh, using data from hospital records of 420 suspected ACS patients. Patients were divided into two groups based on their Hs-Troponin levels, with group 1 having 60 patients with Hs-Troponin ≤0.014 ug/L, and group 2 having 360 patients with Hs-Troponin >0.014 ug/L. Patients less than 18 years old and those with incomplete records were excluded. Ethical approval was obtained, and SPSS v.25 was used for analysis. Results: Group 1 had a significantly younger mean age of 41.8±14.3 compared to Group 2’s mean age of 68.4±12.6, with a p-value less than 0.001. Group 2 had a higher percentage of male patients (70.56%) compared to Group 1 (31.67%), with a p-value of less than 0.01. Group 2 had a significantly higher mean heart rate of 80.18±20.64 beats per minute compared to Group 1’s mean heart rate of 71.02±12.21, with a p-value less than 0.001. There were no significant differences between the two groups in terms of systolic blood pressure, diastolic blood pressure, BMI, history of smoking, history of AMI, hypertension, and diabetes mellitus. Group 1 had a significantly lower percentage of patients with hypercholesterolemia (55.00%), but a higher percentage of patients with a history of ACS (25.00%), and a family history of CAD (70.00%) compared to Group 2, with p-values less than 0.001. Group 2 had a significantly higher percentage of patients with known renal failure (21.67%) compared to Group 1 (1.67%), with a p-value less than 0.001. Creatinine levels were significantly higher in Group 2 (98±53 µmol/L) compared to Group 1 (76±17 µmol/L) with a p-value of less than 0.001, and eGFR was significantly lower in Group 2 (76±27 mL/min/1.73 m2) compared to Group 1 (97±23 mL/min/1.73 m2) with a p-value of less than 0.001. The cardiac Troponin T (cTnT) levels were significantly higher in Group 2 (0.28±1.68 ug/L) compared to Group 1 (0.01±0.01 ug/L) with a p-value of less than 0.001, indicating worse kidney function and cardiac damage in Group 2 compared to Group 1. Conclusion: The study found that very few patients presenting with ACS symptoms had normal Hs-Troponin levels, and ultimate diagnosis proved that they did not have ACS, indicating the usability of Hs-Troponin as a biomarker for ACS. Significant differences were observed in age, gender, heart rate, hypercholesterolemia, family history of ACS, family history of CAD, and renal failure between the two groups. The study also found a consistent association between elevated creatinine levels and lower eGFR with higher Hs-Troponin levels.