99 Delta Troponin Does Not Predict a Major Cardiac Event in Patients With Renal Dysfunction

Abstract

Determine if delta conventional or delta high sensitivity troponin add value in determining a major adverse coronary event (MACE) in renal patients with an elevated troponin. This retrospective cohort study of emergency department (ED) patients diagnosed with chest pain, angina, unstable angina, or myocardial infarction (ICD-10 codes R07, I20, I21) was conducted from January 1 to November 27, 2018 at a tertiary care academic ED center (annual volume 95,000). Inclusion criteria consisted of: 1) renal dysfunction (defined as an eGFR < 60 ml/min/1.72m2); 2) initial positive troponin; 3) at least two troponin measurements within 24 hours. The Roche® 4th generation conventional troponin (cTnT) was used until June 12 with a positive troponin defined as ≥0.06ng/mL. Then, the Roche® 5th generation high sensitivity troponin (hsTnT) was used with a positive troponin defined as ≥52ng/L. A significant delta troponin was defined as a rise or fall of at least 20% from the initial troponin. All patients were then reviewed for a MACE, defined as cardiac-related mortality, need for a coronary stent or bypass graft, or clinically diagnosed type 1 or 2 myocardial infarction within 6 weeks of initial ED visit. 6,360 ED chest pain patients were included in the study. 1,213 patients had renal dysfunction with eGFR < 60 (mean eGFR 38.8 ± 17), and of these ED chest pain renal patients, 303 patients (25%) had a positive troponin. 18 patients were excluded for having a single troponin. In total, 285 patients met inclusion criteria. For the 114 renal patients with a positive cTnT (69 ±13 years old, 62% male), 54 had a MACE (prevalence = 47.3%) with only 27 patients having significant delta troponins (PPV = 65.9%) (see Table). In the 60 patients without a MACE, 46 patients had insignificant delta troponins (NPV = 63%). The positive likelihood ratio (+LR) of a delta cTnT detecting a MACE was very low and nearly approached insignificance at 2.14 (95% CI 1.26, 3.64). The negative likelihood ratio (-LR) of a delta cTnT to exclude a MACE also nearly approached insignificance at 0.65 (95% 0.48, 0.88). For the 171 renal patients with a positive hsTnT (70±14 years, 58% male), 69 had a MACE (prevalence = 40.4%) with only 23 patients having significant delta troponins (PPV = 65.7%). In the 102 patients without a MACE, 90 patients had insignificant delta troponins (NPV = 66.2%). The +LR of a delta hsTnT to detect a MACE was very low and nearly approached insignificance at 2.83 (95% CI 1.51, 5.31). The -LR of a delta hsTnT to exclude a MACE also nearly approached insignificance at 0.70 (95% CI 0.63, 0.91). The Fourth Universal Definition for Myocardial Infarction recommends a rise or fall of cardiac troponin greater than 20% to diagnose a myocardial infarction in renal dysfunction patients. However, this study of renal patients with elevated troponin levels shows that measuring a delta using either conventional or high sensitivity troponin does not add value to determine a MACE.Tabled 1Conventional and High Sensitivity Delta Troponins in Predicting MACERenal dysfunct ED CP+TnT# PtsSensSpecifPPV (95% CI)NPV (95% CI)+LR (95% CI)-LR (95% CI)Delta cTnT11450%76.7%65.9% (+/-1.9%)63.0% (+/- 1.9%)2.14 [1.26, 3.64]0.65 [0.48, 0.88]Delta hsTnT17133.3%88.2%65.7% (+/- 1.9%)66.2% (+/- 1.9%)2.83 [1.51, 5.31]0.76 [0.63, 0.91] Open table in a new tab