Outcomes in syncope research: a systematic review and critical appraisal

Developing Implementation Strategies to Support the Uptake of a Risk Tool to Aid Physicians in the Clinical Management of Patients With Syncope: Systematic Theoretical and User-Centered Design Approach

BACKGROUND

The Canadian Syncope Risk Score (CSRS) was developed to improve syncope management in emergency department settings. Evidence-based tools often fail to have the intended impact because of suboptimal uptake or poor implementation.

OBJECTIVE

In this paper, we aimed to describe the process of developing evidence-based implementation strategies to support the deployment and use of the CSRS in real-world emergency department settings to improve syncope management among physicians.

METHODS

We followed a systematic approach for intervention development, including identifying who needs to do what differently, identifying the barriers and enablers to be addressed, and identifying the intervention components and modes of delivery to overcome the identified barriers. We used the Behaviour Change Wheel to guide the selection of implementation strategies. We engaged CSRS end users (ie, emergency medicine physicians) in a user-centered design approach to generate and refine strategies. This was achieved over a series of 3 qualitative user-centered design workshops lasting 90 minutes each with 3 groups of emergency medicine physicians.

RESULTS

A total of 14 physicians participated in the workshops. The themes were organized according to the following intervention development steps: theme 1-identifying and refining barriers and theme 2-identifying the intervention components and modes of delivery. Theme 2 was subdivided into two subthemes: (1) generating high-level strategies and developing strategies prototypes and (2) refining and testing strategies. The main strategies identified to overcome barriers included education in the format of meetings, videos, journal clubs, and posters (to address uncertainty around when and how to apply the CSRS); the development of a web-based calculator and integration into the electronic medical record (to address uncertainty in how to apply the CSRS); a local champion (to address the lack of team buy-in); and the dissemination of evidence summaries and feedback through email communications (to address a lack of evidence about impact).

CONCLUSIONS

The ability of the CSRS to effectively improve patient safety and syncope management relies on broad buy-in and uptake across physicians. To ensure that the CSRS is well positioned for impact, a comprehensive suite of strategies was identified to address known barriers.

Diagnostic approaches to syncope in Internal Medicine Departments and their effect on mortality

Most data on mortality and investigational approaches to syncope comes from patients presented to emergency departments (ED). The aim of this study is to report intermediate term mortality in syncope patients admitted to Internal Medicine Departments and whether different diagnostic approaches to syncope affect mortality. Methods and results A single-center retrospective-observational study conducted at the Tel Aviv "Sourasky" Medical Center. Data was collected from electronic medical records (EMRs), from January 2010 to December 2020. We identified 24,021 patients, using ICD-9-CM codes. Only 7967 syncope patients were admitted to Internal Medicine Departments and evaluated. Logistic regression models were used to determine the effects of diagnostic testing per patient in each department on 30-day mortality and readmission rates. All-cause 30-day mortality rate was 4.1%. There was a significant difference in the number of diagnostic tests performed per patient between the different departments, without affecting 30-day mortality. The 30-day readmission rate was 11.4%, of which 4.4% were a result of syncope. Conclusion Syncope patients admitted to Internal Medicine Departments show a 30-day all-cause mortality rate of ∼4%. Despite the heterogeneity in the approach to the diagnosis of syncope, mortality is not affected. This novel information about syncope patients in large Internal Medicine Departments is further proof that the diagnosis of syncope requires a logic, personalized approach that focuses on medical history and a few tailored, diagnostic tests.

Cardiac and Vascular Causes of Syncope and Atherosclerosis

PURPOSE OF REVIEW

Among the most common causes of cardiac syncope are arrhythmias and ischemic heart disease, both of which can coexist. The purpose of this review is to discuss the main causes of cardiac and vascular syncope related to atherosclerosis, its epidemiological and clinical aspects, warning signs, and initial approach.

RECENT FINDINGS

Cardiac syncope may have a frequency of up to 34% in elderly people. Atherosclerosis-related causes of cardiac and vascular syncope may be due to cardiac arrhythmia and/or structural impairment of the heart or arteries. Late ventricular tachycardia and late-onset high-grade atrioventricular block associated with myocardial ischemia may occur with syncope, which is related to higher mortality. Besides ventricular dysfunction, concentric remodeling is also a prognostic factor. In calcific degenerative aortic stenosis, syncope carries a worse prognosis than the other cardinal signs. Cardiac syncope has a high recurrence and mortality rate. There are red flag alerts that must be considered in risk stratification.

The ability of Canadian Syncope risk score in differentiating cardiogenic and non-cardiogenic syncope; a cross-sectional study

INTRODUCTION

Determining the underlying etiology of syncope provides valuable prognostic information and expedites the implementation of a therapeutic strategy. This study aimed to evaluate the ability of Canadian Syncope Risk Score (CSRS) in differentiating cardiogenic and non-cardiac syncope.

METHODS

The present diagnostic accuracy study was conducted on adult patients with syncope, who presented to the emergency departments of Shohadaye Tajrish and Imam Hossein Hospitals in Tehran from March 2018 to March 2019. The data required for determining CSRS were collected during the initial assessment and the underlying etiology was confirmed through further diagnostic follow-up under the supervision of a cardiologist or neurologist. Finally, the screening performance characteristics of the score were calculated.

RESULTS

300 patients with the mean age of 56.38 ± 19.10 years were studied. The source of syncope was cardiac in 133 (44.3%) and non-cardiac in 137 (55.7%) patients. The area under the ROC curve of CSRS in differentiating cardiac syncope was 0.77 (95% CI: 0.715-0.824). At a cutoff point of -1.5, the sensitivity and specificity of the score were calculated to be 73.68% (95% CI: 65.21-80.75%) and 73.05% (95%CI: 75.54-79.47%), respectively.

CONCLUSION

The present study reveals that CSRS has fair accuracy in differentiating the source of syncope and has no superiority over a clinical examination. Therefore, we do not recommend relying on the CSRS to differentiate between cardiac and non-cardiac syncope alone.

Syncope Time Frames for Adverse Events after Emergency Department Presentation: An Individual Patient Data Meta-Analysis

Background and Objectives: Knowledge of the incidence and time frames of the adverse events of patients presenting syncope at the ED is essential for developing effective management strategies. The aim of the present study was to perform a meta-analysis of the incidence and time frames of adverse events of syncope patients. Materials and Methods: We combined individual patients’ data from prospective observational studies including adult patients who presented syncope at the ED. We assessed the pooled rate of adverse events at 24 h, 72 h, 7–10 days, 1 month and 1 year after ED evaluation. Results: We included nine studies that enrolled 12,269 patients. The mean age varied between 53 and 73 years, with 42% to 57% females. The pooled rate of adverse events was 5.1% (95% CI 3.4% to 7.7%) at 24 h, 7.0% (95% CI 4.9% to 9.9%) at 72 h, 8.4% (95% CI 6.2% to 11.3%) at 7–10 days, 10.3% (95% CI 7.8% to 13.3%) at 1 month and 21.3% (95% CI 15.8% to 28.0%) at 1 year. The pooled death rate was 0.2% (95% CI 0.1% to 0.5%) at 24 h, 0.3% (95% CI 0.1% to 0.7%) at 72 h, 0.5% (95% CI 0.3% to 0.9%) at 7–10 days, 1% (95% CI 0.6% to 1.7%) at 1 month and 5.9% (95% CI 4.5% to 7.7%) at 1 year. The most common adverse event was arrhythmia, for which its rate was 3.1% (95% CI 2.0% to 4.9%) at 24 h, 4.8% (95% CI 3.5% to 6.7%) at 72 h, 5.8% (95% CI 4.2% to 7.9%) at 7–10 days, 6.9% (95% CI 5.3% to 9.1%) at 1 month and 9.9% (95% CI 5.5% to 17) at 1 year. Ventricular arrhythmia was rare. Conclusions: The risk of death or life-threatening adverse event is rare in patients presenting syncope at the ED. The most common adverse events are brady and supraventricular arrhythmias, which occur during the first 3 days. Prolonged ECG monitoring in the ED in a short stay unit with ECG monitoring facilities may, therefore, be beneficial.

Multicentre external validation of the Canadian Syncope Risk Score to predict adverse events and comparison with clinical judgement

BACKGROUND

The Canadian Syncope Risk Score (CSRS) has been proposed for syncope risk stratification in the emergency department (ED). The aim of this study is to perform an external multicenter validation of the CSRS and to compare it with clinical judgement.

METHODS

Using patients previously included in the SyMoNE database, we enrolled subjects older than 18 years who presented reporting syncope at the ED. For each patient, we estimated the CSRS and recorded the physician judgement on the patients' risk of adverse events. We performed a 30-day follow-up.

RESULTS

From 1 September 2015 to 28 February 2017, we enrolled 345 patients; the median age was 71 years (IQR 51-81), 174 (50%) were men and 29% were hospitalised. Serious adverse events occurred in 43 (12%) of the patients within 30 days. The area under the curve of the CSRS and clinical judgement was 0.75 (95% CI 0.68 to 0.81) and 0.68 (95% CI 0.61 to 0.74), respectively. The risk of adverse events of patients at low risk according to the CSRS and clinical judgement was 6.7% and 2%, with a sensitivity of 70% (95% CI 54% to 83%) and 95% (95% CI 84% to 99%), respectively.

CONCLUSION

This study represents the first validation analysis of CSRS outside Canada. The overall predictive accuracy of the CSRS is similar to the clinical judgement. However, patients at low risk according to clinical judgement had a lower incidence of adverse events as compared with patients at low risk according to the CSRS. Further studies showing that the adoption of the CSRS improve patients' outcomes is warranted before its widespread implementation.

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.

Does N-Terminal Pro-B-Type Natriuretic Peptide Improve the Risk Stratification of Emergency Department Patients With Syncope?

BACKGROUND

Studies have reported that natriuretic peptides provide prognostic information for emergency department (ED) syncope.

OBJECTIVE

To evaluate whether adding N-terminal pro-B-type natriuretic peptide (NT-proBNP) to the Canadian Syncope Risk Score (CSRS) improves prediction of 30-day serious adverse events (SAEs).

DESIGN

Prospective cohort study.

SETTING

6 EDs in 2 Canadian provinces.

PARTICIPANTS

1452 adult ED patients with syncope.

INTERVENTION

Serum NT-proBNP was measured locally at 1 site and batch processed at a central laboratory from other sites. The concentrations were not available to treating physicians or for adjudication of outcomes.

MEASUREMENTS

An adjudicated composite outcome of 30-day SAEs, including death and cardiac (arrhythmic and nonarrhythmic) and noncardiac events.

RESULTS

Of 1452 patients enrolled, 152 (10.5% [95% CI, 9.0% to 12.1%]) had 30-day SAEs, 57 (3.9%) of which were identified after the index ED disposition. Serum NT-proBNP concentrations were significantly higher among patients with SAEs than those without them (median, 626.5 ng/L vs. 81 ng/L; P < 0.001). Adding NT-proBNP values to the CSRS did not significantly improve prognostication (c-statistic, 0.89 and 0.90; P = 0.12 for difference), regardless of SAE subgroup or whether the SAE was identified after the index ED visit. The net reclassification index shows that NT-proBNP would have correctly reclassified 3% of patients with SAEs at the expense of incorrectly reclassifying 2% of patients without SAEs.

LIMITATIONS

Our study was powered to detect a 3% difference in the area under the curve. The heterogeneity of outcomes and robust baseline discrimination by the CSRS will make improvements challenging.

CONCLUSION

Although serum NT-proBNP concentrations were generally much higher among ED patients with syncope who had a 30-day SAE, this blood test added little new information to the CSRS. Routine use of NT-proBNP for ED syncope prognostication is not recommended.

PRIMARY FUNDING SOURCE

Physicians' Services Incorporated Foundation, Canadian Institutes of Health Research, and The Ottawa Hospital Academic Medical Organization.

Personalized risk stratification through attribute matching for clinical decision making in clinical conditions with aspecific symptoms: The example of syncope

BACKGROUND

Risk stratification is challenging in conditions, such as chest pain, shortness of breath and syncope, which can be the manifestation of many possible underlying diseases. In these cases, decision tools are unlikely to accurately identify all the different adverse events related to the possible etiologies. Attribute matching is a prediction method that matches an individual patient to a group of previously observed patients with identical characteristics and known outcome. We used syncope as a paradigm of clinical conditions presenting with aspecific symptoms to test the attribute matching method for the prediction of the personalized risk of adverse events.

METHODS

We selected the 8 predictor variables common to the individual-patient dataset of 5 prospective emergency department studies enrolling 3388 syncope patients. We calculated all possible combinations and the number of patients in each combination. We compared the predictive accuracy of attribute matching and logistic regression. We then classified ten random patients according to clinical judgment and attribute matching.

RESULTS

Attribute matching provided 253 of the 384 possible combinations in the dataset. Twelve (4.7%), 35 (13.8%), 50 (19.8%) and 160 (63.2%) combinations had a match size ≥50, ≥30, ≥20 and <10 patients, respectively. The AUC for the attribute matching and the multivariate model were 0.59 and 0.74, respectively.

CONCLUSIONS

Attribute matching is a promising tool for personalized and flexible risk prediction. Large databases will need to be used in future studies to test and apply the method in different conditions.

Predictive Accuracy of Electrocardiographic Monitoring of Patients With Syncope in the Emergency Department: The SyMoNE Multicenter Study

BACKGROUND

Arrhythmia is one of the most worrisome causes of syncope. Electrocardiographic (ECG) monitoring is crucial for the management of non-low-risk patients in the emergency department (ED). However, its diagnostic accuracy and optimal duration are unknown. We aimed to assess the diagnostic accuracy of ECG monitoring in non-low-risk patients with syncope in the ED.

METHODS

This prospective multicenter observational study included adult patients presenting to the ED after syncope. Patients without an obvious etiology after ED evaluation who were classified by ED physicians as being at non-low risk of adverse events underwent ECG monitoring. We assessed sensitivity, specificity, and diagnostic yield (defined as the proportion of patients with true-positive ECG monitoring findings) of ECG monitoring in the identification of 7- and 30-day adverse and arrhythmic events according to monitoring duration.

RESULTS

Of 242 patients included in the study, 29 patients had 7-day serious outcomes. Ten additional patients had serious outcomes at 30 days. The overall sensitivity, specificity, and diagnostic yield of ECG monitoring in the identification of 7-day adverse events were 0.55 (95% confidence interval [CI] = 0.36 to 0.74], 0.93 (95% CI = 0.89 to 0.96), and 0.07 (95% CI = 0.04 to 0.10), respectively. The sensitivity, specificity, and diagnostic yield of >12-hour ECG monitoring in the identification of 7-day adverse events were 0.89 (95% CI = 0.65 to 0.99), 0.78 (95% CI = 0.67 to 0.87), and 0.18 (95% CI = 0.12 to 0.28), respectively. Similar results were observed for 30-day adverse events. The median (interquartile range) ECG monitoring time was 6.5 (6 to 15) hours. ECG monitoring findings were positive in 31 patients.

CONCLUSIONS

Although the overall diagnostic accuracy of ECG monitoring is fair, its sensitivity at >12 hours' duration is substantially higher. These results suggest that prolonged (>12 hours) monitoring is a safe alternative to hospital admission in the management of non-low-risk patients with syncope in the ED.

Did This Patient Have Cardiac Syncope?: The Rational Clinical Examination Systematic Review

IMPORTANCE

Syncope can result from a reduction in cardiac output from serious cardiac conditions, such as arrhythmias or structural heart disease (cardiac syncope), or other causes, such as vasovagal syncope or orthostatic hypotension.

OBJECTIVE

To perform a systematic review of studies of the accuracy of the clinical examination for identifying patients with cardiac syncope.

STUDY SELECTION

Studies of adults presenting to primary care, emergency departments, or referred to specialty clinics.

DATA EXTRACTION AND SYNTHESIS

Relevant data were abstracted from articles in databases through April 9, 2019, and methodologic quality was assessed. Included studies had an independent comparison to a reference standard.

MAIN OUTCOMES AND MEASURES

Sensitivity, specificity, and likelihood ratios (LRs).

RESULTS

Eleven studies of cardiac syncope (N = 4317) were included. Age at first syncope of at least 35 years was associated with greater likelihood of cardiac syncope (n = 323; sensitivity, 91% [95% CI, 85%-97%]; specificity, 72% [95% CI, 66%-78%]; LR, 3.3 [95% CI, 2.6-4.1]), while age younger than 35 years was associated with a lower likelihood (LR, 0.13 [95% CI, 0.06-0.25]). A history of atrial fibrillation or flutter (n = 323; sensitivity, 13% [95% CI, 6%-20%]; specificity, 98% [95% CI, 96%-100%]; LR, 7.3 [95% CI, 2.4-22]), or known severe structural heart disease (n = 222; range of sensitivity, 35%-51%, range of specificity, 84%-93%; range of LR, 3.3-4.8; 2 studies) were associated with greater likelihood of cardiac syncope. Symptoms prior to syncope that were associated with lower likelihood of cardiac syncope were mood change or prodromal preoccupation with details (n = 323; sensitivity, 2% [95% CI, 0%-5%]; specificity, 76% [95% CI, 71%-81%]; LR, 0.09 [95% CI, 0.02-0.38]), feeling cold (n = 412; sensitivity, 2% [95% CI, 0%-5%]; specificity, 89% [95% CI, 85%-93%]; LR, 0.16 [95% CI, 0.06-0.64]), or headache (n = 323; sensitivity, 3% [95% CI, 0%-7%]; specificity, 80% [95% CI, 75%-85%]; LR, 0.17 [95% CI, 0.06-0.55]). Cyanosis witnessed during the episode was associated with higher likelihood of cardiac syncope (n = 323; sensitivity, 8% [95% CI, 2%-14%]; specificity, 99% [95% CI, 98%-100%]; LR, 6.2 [95% CI, 1.6-24]). Mood changes after syncope (n = 323; sensitivity, 3% [95% CI, 0%-7%]; specificity, 83% [95% CI, 78%-88%]; LR, 0.21 [95% CI, 0.06-0.65]) and inability to remember behavior prior to syncope (n = 323; sensitivity, 5% [95% CI, 0%-9%]; specificity, 82% [95% CI, 77%-87%]; LR, 0.25, [95% CI, 0.09-0.69]) were associated with lower likelihood of cardiac syncope. Two studies prospectively validated the accuracy of the multivariable Evaluation of Guidelines in Syncope Study (EGSYS) score, which is based on 6 clinical variables. An EGSYS score of less than 3 was associated with lower likelihood of cardiac syncope (n = 456; range of sensitivity, 89%-91%, range of specificity, 69%-73%; range of LR, 0.12-0.17; 2 studies). Cardiac biomarkers show promising diagnostic accuracy for cardiac syncope, but diagnostic thresholds require validation.

CONCLUSIONS AND RELEVANCE

The clinical examination, including the electrocardiogram as part of multivariable scores, can accurately identify patients with and without cardiac syncope.