Do High-sensitivity Troponin and Natriuretic Peptide Predict Death or Serious Cardiac Outcomes After Syncope?

Performance of high-sensitivity cardiac troponin T in predicting major cardiovascular events in patients admitted to the emergency department for syncope with normal ECG: An observational prospective study

INTRODUCTION

History of syncope, clinical examination and electrocardiographic (ECG) findings are fundamental to assess the risk of major cardiovascular events (MACE) in patients attending the emergency department (ED) for syncope. However, in the absence of abnormal clinical examination findings or an abnormal ECG in the ED, transient rhythm or conduction disorders may not be safely excluded, hence predicting MACE remains challenging. High-sensitivity cardiac troponin T (hs-cTnT) may be a useful tool in this context.

AIM

The primary objective was to evaluate the performance of hs-cTnT in the diagnosis of MACE at 30 days in patients attending the ED for syncope with a normal initial ECG.

METHODS

This was a prospective observational cohort study that took place in the ED of a French university hospital between June 2018 and June 2019. Patients≥18 years admitted to the ED for syncope with a normal ECG were eligible. After receiving verbal consent from patients, the ED physician collected clinical and ECG data and all patients had a blood sample taken that included hs-cTnT measurement. The primary outcome was MACE within 30 days after the ED visit. MACE were evaluated by consulting the patient's medical records and telephoning patients or their general practitioners. Sensitivity, specificity, positive and negative predictive values were calculated with their 95% confidence intervals (CI) for different hs-cTnT thresholds.

RESULTS

Data from 246 patients were analysed, including 21 (9%) with MACE. Hs-cTnT had an area under the curve of 0.917 (CI: 0.872-0.962). Hs-cTnT with a threshold of 19ng/L had a sensitivity of 86% (CI: 64-97) and a specificity of 86% (CI: 81-90) for predicting MACE.

CONCLUSION

Hs-cTnT may be a relevant tool for assessing MACE risk in patients with syncope and normal ECG results.

Diagnostic accuracy of high sensitivity troponin and association of electrocardiogram findings for mortality in syncope patients: A retrospective cohort study

High-sensitivity cardiac troponin-T (hs-cTnT) and electrocardiogram (ECG) are commonly ordered in daily practice in emergency medicine but their value on long term mortality in syncope patients is unclear. Our aim is to determine the diagnostic accuracy of hs-cTnT and association of ECG findings for 1-year mortality in patients presenting with syncope. In this retrospective cohort study, we included patients presenting with syncope to the emergency department (ED) between May 2020 and May 2021. Patient demographics, vital parameters on admission, ECG findings, hs-cTnT level at admission and 1-year mortality status were recorded. The study included 417 patients (62.4% women) with a mean age of 41.51 (standard deviation [SD] 17.1), 21 of whom were deceased within 1 year after syncope attack (5%). Patients with an abnormal QTc, T-Axis or frontal QRS-T angle had significantly higher 1-year mortality (OR: 9.26, 95% CI: 1.64-52.31; OR: 5.82, 95% CI: 1.69-20.1; 4.94, 95% CI: 1.45-16.84, respectively). The hs-cTnT level was 21.92 pg/mL (95% CI: 3.35-40.51 pg/mL) higher in the mortality group (P = .023). An abnormal QTc, T-Axis and frontal QRS-T angle are associated with a higher 1-year mortality rate and hs-cTnT has good diagnostic accuracy in detecting 1-year mortality for patients presenting with syncope.

Comparison between standard and ultrasound-integrated approach for risk stratification of syncope in the emergency department

This prospective cohort enrolled all patients above 16 years of age presenting to the in the emergency department (ED) for a reported syncope was designed to test the accuracy of a point-of-care ultrasound (POCUS) integrated approach in risk stratification. The emergency physician responsible for the patient care was asked to classify the syncope risk after the initial clinical assessment and after performing POCUS evaluation. All risk group definitions were based on the 2018 European Society of Cardiology guidelines. Thirty days after the index event, all participants were followed up to assess the frequency of short-term serious outcomes as defined in the San Francisco Syncope Rule (SFSR) cohorts. We estimated the accuracy of clinical and POCUS-integrated evaluation in predicting SFSR outcomes. Between February 2016 and January 2018, 196 patients were enrolled [109 women (55.6%)]. Median age was 64 years (interquartile range 31 years). After a follow-up of 30 days, 19 patients experienced 20 SFSR outcomes. Positive and negative likelihood ratios were 1.73 (95% CI 0.87-3.44) and 0.84 (95% CI 0.62-1.12) for the clinical evaluation, and 5.93 (95% CI 2.83-12.5) and 0.63 (95% CI 0.45-0.9) for the POCUS-integrated evaluation. The POCUS-integrated approach would reduce the diagnostic error of the clinical evaluation by 4.5 cases/100 patients. This cohort study suggested that the integration of the clinical assessment with POCUS results in patients presenting to the ED for non-high-risk syncope may increase the accuracy of predicting the risk of SFSR outcomes and the usefulness of the clinical assessment alone.

Risk stratification of syncope: Current syncope guidelines and beyond

Syncope is an alarming event carrying the possibility of serious outcomes, including sudden cardiac death (SCD). Therefore, immediate risk stratification should be applied whenever syncope occurs, especially in the Emergency Department, where most dramatic presentations occur. It has long been known that short- and long-term syncope prognosis is affected not only by its mechanism but also by presence of concomitant conditions, especially cardiovascular disease. Over the last two decades, several syncope prediction tools have been developed to refine patient stratification and triage patients who need expert in-hospital care from those who may receive nonurgent expert care in the community. However, despite promising results, prognostic tools for syncope remain challenging and often poorly effective. Current European Society of Cardiology syncope guidelines recommend an initial syncope workup based on detailed patient's history, physical examination supine and standing blood pressure, resting ECG, and laboratory tests, including cardiac biomarkers, where appropriate. Subsequent risk stratification based on screening of features aims to identify three groups: high-, intermediate- and low-risk. The first should immediately be hospitalized and appropriately investigated; intermediate group, with recurrent or medium-risk events, requires systematic evaluation by syncope experts; low-risk group, sporadic reflex syncope, merits education about its benign nature, and discharge. Thus, initial syncope risk stratification is crucial as it determines how and by whom syncope patients are managed. This review summarizes the crucial elements of syncope risk stratification, pros and cons of proposed risk evaluation scores, major challenges in initial syncope management, and how risk stratification impacts management of high-risk/recurrent syncope.

Sex differences in cardiopulmonary effects of acute bromine exposure

Accidental occupational bromine (Br>2>) exposures are common, leading to significant morbidity and mortality; however, the specific effects of Br>2> inhalation in female victims are unclear. Our studies demonstrated that acute high-concentration Br>2> inhalation is fatal, and cardiac injury and dysfunction play an important role in Br>2> toxicity in males. In this study, we exposed female Sprague Dawley rats, age-matched to those males from previously studied, to 600 ppm Br>2> for 45 min and assessed their survival, cardiopulmonary injury and cardiac function after exposure. Br>2> exposure caused serious mortality in female rats (59%) 48 h after exposure. Rats had severe clinical distress, reduced heart rates and oxygen saturation after Br>2> inhalation as was previously reported with male animals. There was significant lung injury and edema when measured 24 h after exposure. Cardiac injury biomarkers were also significantly elevated 24 h after Br>2> inhalation. Echocardiography and hemodynamic studies were also performed and revealed that the mean arterial pressure was not significantly elevated in females. Other functional cardiac parameters were also altered. Aside from the lack of elevation of blood pressure, all other changes observed in female animals were also present in male animals as reported in our previous study. These studies are important to understand the toxicity mechanisms to generate therapies and better-equip first responders to deal with these specific scenarios after bromine spill disasters.>.

Multivariable risk scores for predicting short-term outcomes for emergency department patients with unexplained syncope: A systematic review

OBJECTIVES

Emergency department (ED) patients with unexplained syncope are at risk of experiencing an adverse event within 30 days. Our objective was to systematically review the accuracy of multivariate risk stratification scores for identifying adult syncope patients at high and low risk of an adverse event over the next 30 days.

METHODS

We conducted a systematic review of electronic databases (MEDLINE, Cochrane, Embase, and CINAHL) from database creation until May 2020. We sought studies evaluating prediction scores of adults presenting to an ED with syncope. We included studies that followed patients for up to 30 days to identify adverse events such as death, myocardial infarction, stroke, or cardiac surgery. We only included studies with a blinded comparison between baseline clinical features and adverse events. We calculated likelihood ratios and confidence intervals (CIs).

RESULTS

We screened 13,788 abstracts. We included 17 studies evaluating nine risk stratification scores on 24,234 patient visits, where 7.5% (95% CI = 5.3% to 10%) experienced an adverse event. A Canadian Syncope Risk Score (CSRS) of 4 or more was associated with a high likelihood of an adverse event (LR_score≥4  = 11, 95% CI = 8.9 to 14). A CSRS of 0 or less (LR_score≤0  = 0.10, 95% CI = 0.07 to 0.20) was associated with a low likelihood of an adverse event. Other risk scores were not validated on an independent sample, had low positive likelihood ratios for identifying patients at high risk, or had high negative likelihood ratios for identifying patients at low risk.

CONCLUSION

Many risk stratification scores are not validated or not sufficiently accurate for clinical use. The CSRS is an accurate validated prediction score for ED patients with unexplained syncope. Its impact on clinical decision making, admission rates, cost, or outcomes of care is not known.

Chronic cardiac structural damage, diastolic and systolic dysfunction following acute myocardial injury due to bromine exposure in rats

Accidental bromine spills are common and its large industrial stores risk potential terrorist attacks. The mechanisms of bromine toxicity and effective therapeutic strategies are unknown. Our studies demonstrate that inhaled bromine causes deleterious cardiac manifestations. In this manuscript we describe mechanisms of delayed cardiac effects in the survivors of a single bromine exposure. Rats were exposed to bromine (600 ppm for 45 min) and the survivors were sacrificed at 14 or 28 days. Echocardiography, hemodynamic analysis, histology, transmission electron microscopy (TEM) and biochemical analysis of cardiac tissue were performed to assess functional, structural and molecular effects. Increases in right ventricular (RV) and left ventricular (LV) end-diastolic pressure and LV end-diastolic wall stress with increased LV fibrosis were observed. TEM images demonstrated myofibrillar loss, cytoskeletal breakdown and mitochondrial damage at both time points. Increases in cardiac troponin I (cTnI) and N-terminal pro brain natriuretic peptide (NT-proBNP) reflected myofibrillar damage and increased LV wall stress. LV shortening decreased as a function of increasing LV end-systolic wall stress and was accompanied by increased sarcoendoplasmic reticulum calcium ATPase (SERCA) inactivation and a striking dephosphorylation of phospholamban. NADPH oxidase 2 and protein phosphatase 1 were also increased. Increased circulating eosinophils and myocardial 4-hydroxynonenal content suggested increased oxidative stress as a key contributing factor to these effects. Thus, a continuous oxidative stress-induced chronic myocardial damage along with phospholamban dephosphorylation are critical for bromine-induced chronic cardiac dysfunction. These findings in our preclinical model will educate clinicians and public health personnel and provide important endpoints to evaluate therapies.

[Diagnostic value of high-sensitivity troponin I to predict cardiac causes after syncope/near syncope in emergency department]

AIMS

The objective of this study is to evaluate the diagnostic accuracy of high-sensitivity (hs) troponin I to predict cardiac origin after syncope. The secondary objective is to determine the causes of elevated troponin.

PROCEDURE

Were included hospitalized patients with syncope/near syncope diagnosed in ED. The diagnostic accuracy to predict cardiac origin was evaluated and compared to the "high risk" group, defined by the 2018 European Society of Cardiology guidelines.

RESULTS

A total of 163 patients were enrolled, 26% had a cardiac origin. Positive troponin I hs predict a cardiac origin with a sensitivity of 31%, a specificity of 80%, positive predictive value of 35% and negative value of 77%. These diagnostic performances are not discriminating and lower than the ESC classification. A positive troponine I hs level is associated with 5 times more cardiac failure during the hospitalization.

CONCLUSION

A positive troponin I hs level after syncope/near syncope is not predictive of cardiac origin. It appears to be an early marker of ventricular remodeling in heart failure.

Prognosis of Syncope With Head Injury: a Tertiary Center Perspective

Aim: Head injury is the most common trauma occurring in syncope. We aimed to assess whether syncope as cause of head-trauma affects short-and long-term prognosis.

Methods: From a database retrospective analysis of 97,014 individuals attending Emergency Department (ED), we selected data of patients with traumatic head injury including age, gender, injury mechanism, brain imaging, multiple traumas, bone fracture, intracranial bleeding, and mortality. Mean follow-up was 6.4 ± 1.8 years. Outcome data were obtained from a digital national population register. The study population included 3,470 ED head injury patients: 117 of them (50.0 ± 23.6 years, 42.7% men) reported syncope as cause of head trauma and 3,315 (32.2 ± 21.1 years, 68.5% men) without syncope preceding head trauma.

Results: Thirty-day mortality was low and similar in traumatic head injury with or without syncope. One year and long-term all-cause mortality were both significantly higher in syncopal vs. non-syncopal traumatic head injury (11.1 vs. 2.8% and 32 vs. 10.2%, respectively; both p < 0.001). In adjusted logistic regression analysis, death between 121st-day and 1 year in patients with head-trauma was associated with male gender [odds ratio (OR): 6.48; 95% CI: 2.59–16.25], advancing age (per year) (OR 1.09; 95% CI 1.07–1.11), Glasgow Coma Scale < 13 (OR: 6.18; 95% CI:1.68–22.8), bone fracture (OR 4.72; 95% CI 2.13–10.5), and syncope (OR 3.70; 95% CI: 1;48–9.31). In multivariable Cox regression analysis, syncope was one of the strongest independent predictors of long-term all-cause death (hazard ratio: 1.95; 95% CI 1.37–2.78).

Conclusion: In patients with head trauma, history of syncope preceding injury does not increase 30-day all-cause mortality but portends increased 1 year and long-term mortality.