Confounding factors in the relation between high sensitivity cardiac troponin T levels in serum and infarct size of patients with first ST-elevation myocardial infarction

Severe Impairment of Left Ventricular Regional Strain in STEMI Patients Is Associated with Post-Infarct Remodeling

Background: Measures of global left ventricular (LV) systolic function have limitations for the prediction of post-infarct LV remodeling (LVR). Therefore, we tested the association between a new measure of regional LV systolic function—the percentage of severely altered strain (%SAS)- and LVR after acute ST-elevation myocardial infarction (STEMI). As a secondary objective, we also evaluated the association between %SAS and clinical events during follow-up. Methods: Of 177 patients undergoing echocardiography within 24 h from primary percutaneous coronary angioplasty, 172 were studied for 3 months, 167 for 12 months, and 10 died. The %SAS was calculated by dividing the number of LV myocardial segments with ≥−5% peak systolic longitudinal strain by the total number of segments. LVR was defined as the increase in end-diastolic volume >20% at its first occurrence compared to baseline. Results: LVR percentage was 10.2% and 15.8% at 3 and 12 months, respectively. Based on univariable analysis, a number of clinical, laboratory, electrocardiographic and echocardiographic variables were associated with LVR. Based on multivariable analysis, %SAS and TnI peak remained associated with LVR (for %SAS 5% increase, OR 1.226, 95% CI 1.098−1.369, p < 0.0005; for TnI peak, OR 1.025, 95% CI 1.004−1.047, p = 0.022). %SAS and LVR were also associated with occurrence of clinical events at a median follow-up of 43 months (HR 1.02, 95% CI 1.0−1.04, p = 0.0165). Conclusions: In patients treated for acute STEMI, acute %SAS is associated with post-infarct LVR. Therefore, we suggest performing such evaluations on a routine basis to identify, as early as possible, STEMI patients at higher risk.

Association of Prolonged Emergency Department Length of Stay with Adverse Events in Patients with Non-ST-Elevation Acute Coronary Syndrome

Objective

To study the association between prolonged emergency department length of stay (EDLOS) and in-hospital adverse events in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS).

Methods

In this retrospective cohort study, the medical records of 738 patients diagnosed with NSTE-ACS and admitted to the emergency department (ED) from 1 January 2013 to 31 December 2019 were reviewed. The patients were categorized into groups with EDLOS < 4 hours and EDLOS ≥ 4 hours, and baseline characteristics, clinical presentation, Killip classification, Global Registry of Acute Coronary Events score, investigations, use of the European Society of Cardiology (ESC) 0/1-hour and 0/3-hour algorithms, and treatments in the ED were compared between the groups. The associations of in-hospital adverse events with EDLOS were examined using univariate logistic regression.

Results

Four hundred and twenty-three (57.3%) patients had an EDLOS of ≥ 4 hours, and the median (IQR) EDLOS was 4.48 hours (3.03, 6.20 hours). EDLOS ≥ 4 h was associated with a prolonged time to receive P2Y₁₂ inhibitors and anticoagulants (P < 0.001). However, the two groups showed no significant differences in in-hospital adverse events (congestive heart failure [CHF], shock, stroke or transient ischemic attack [TIA], major bleeding, arrhythmia, recurrent myocardial infarction, death, and one or more adverse events). Nevertheless, a non-significant trend for a higher rate of adverse events (CHF, shock, major bleeding, arrhythmia, recurrent myocardial infarction, death, and one or more adverse events) with longer EDLOS was observed in the subgroup of patients who received diuretic or antiarrhythmic drugs, ventilator or bilevel positive airway pressure support, oxygen support, or inotropic/vasopressor drugs in the ED.

Conclusion

Prolonged EDLOS showed a significant association with longer times to receive P2Y₁₂ inhibitors and anticoagulants. However, the EDLOS < 4 hour and EDLOS ≥ 4 hour groups of patients with NSTE-ACS showed no significant differences in the rates of in-hospital adverse events. Patients who receive cardiovascular medications in the ED or are on respiratory support should be hospitalized as soon as practically possible. Proper use of the 0/1-hour algorithm over the 0/3-hour algorithm without unnecessary repeated cardiac troponin tests in the ED could reduce the EDLOS in patients with NSTE-ACS.

Serum Cardiac Troponin-I is Superior to Troponin-T as a Marker for Left Ventricular Dysfunction in Clinically Stable Patients with End-Stage Renal Disease

Background

Serum troponin assays, widely used to detect acute cardiac ischemia, might be useful biomarkers to detect chronic cardiovascular disease (CVD). Cardiac-specific troponin-I (cTnI) and troponin-T (cTnT) generally detect myocardial necrosis equally well. In dialysis patients however, serum cTnT levels are often elevated, unlike cTnI levels. The present study aims to elucidate the associations of cTnI and cTnT with CVD in clinically stable dialysis patients.

Methods

Troponin levels were measured using 5^th generation hs-cTnT assays (Roche) and STAT hs-cTnI assays (Abbott) in a cohort of dialysis patients. Serum troponin levels were divided into tertiles with the lowest tertile as a reference value. Serum troponins were associated with indicators of CVD such as left ventricular mass index (LVMI), left ventricular ejection fraction (LVEF) and the presence of coronary artery disease (CAD). Associations were explored using regression analysis.

Results

We included 154 consecutive patients, 68±7 years old, 77% male, 70% hemodialysis. Median serum cTnT was 51ng/L (exceeding the 99^th percentile of the healthy population in 98%) and median serum cTnI was 13ng/L (elevated in 20%). A high cTnI (T3) was significantly associated with a higher LVMI (Beta 31.60; p=0.001) and LVEF (Beta -4.78; p=0.005) after adjusting for confounders whereas a high serum cTnT was not. CAD was significantly associated with a high cTnT (OR 4.70 p=0.02) but not with a high cTnI. Unlike cTnI, cTnT was associated with residual renal function (Beta:-0.09; p=0.006).

Conclusion

In the present cohort, serum cTnI levels showed a stronger association with LVMI and LVEF than cTnT. However, cTnT was significantly associated with CAD and residual renal function, unlike cTnI. Therefore, cTnI seems to be superior to cTnT as a marker of left ventricular dysfunction in asymptomatic dialysis patients, while cTnT might be better suited to detect CAD in these patients.