Presyncope Patient Outcomes In Emergency Care
Overview
Syncope is characterized by a transient loss of consciousness, whereas presyncope involves similar prodromal symptoms without the actual loss of consciousness. Although extensive research has examined the risk of serious outcomes in emergency department (ED) patients with syncope, the outcomes and management of patients with presyncope remain underexplored. This systematic review aimed to evaluate the occurrence and identification of short-term (30-day) serious outcomes in ED patients presenting with presyncope. Methods: The review included ED studies that enrolled patients with presyncope and reported any short-term serious outcomes. Studies involving patients with conditions other than presyncope, such as hypoglycemia, seizures, and stroke, were excluded. The review was limited to English-language publications, and searches were conducted in MEDLINE, Embase, Scopus, and Web of Science from their inception to July 2023. The SIGN 50 tool was employed to assess the risk of bias in the included studies.
Introduction
Syncope is defined as a transient loss of consciousness caused by a sudden reduction in cerebral blood flow, leading to global cerebral hypoperfusion. Patients who experience syncope typically recover fully and spontaneously. This condition accounts for roughly 1% of all emergency department (ED) visits, with a significant number of cases involving older adults who are frequently hospitalized due to concerns about potential underlying causes and the risk of serious outcomes. These outcomes can include life-threatening events such as cardiac arrhythmias, myocardial infarction, or even death, both during the initial ED visit and following discharge.
Presyncope, on the other hand, is characterized by the same prodromal symptoms associated with syncope—such as nausea, dizziness, light-headedness, sweating, palpitations, and pallor—but without the progression to complete loss of consciousness. Despite sharing similar symptoms with syncope, presyncope is less well understood in terms of its underlying pathophysiology. It is generally hypothesized that syncope and presyncope are part of a single disease spectrum, with presyncope being a milder manifestation of the same underlying processes that cause syncope.
However, contemporary research indicates that patients presenting with presyncope are less likely to be hospitalized compared to those with syncope. This suggests that emergency physicians often perceive presyncope as a less severe condition with a lower risk of serious outcomes. The types of serious adverse events associated with presyncope, as well as their prevalence, vary considerably across different studies. These serious outcomes may include conditions like cardiac arrhythmias, stroke, or other critical events, though the exact risk remains uncertain due to inconsistent findings in the literature.
Despite the clinical relevance of presyncope, there has been no comprehensive synthesis of the available data on the short-term serious outcomes associated with this condition in ED settings. The lack of a systematic review on this topic represents a significant gap in the literature, particularly in comparison to the more extensively studied outcomes associated with syncope. Understanding the risks linked to presyncope is crucial for improving risk assessment and management strategies in the ED, as it could influence decisions regarding patient admission, monitoring, and treatment.
Therefore, this systematic review was undertaken to evaluate the risk of short-term serious outcomes in patients presenting to the ED with presyncope, with the goal of providing evidence-based guidance for emergency physicians. The review aims to compare the outcomes associated with presyncope to those observed in patients with syncope, under the hypothesis that both conditions are on the same spectrum and thus carry similar risks. By synthesizing the available evidence, this review seeks to clarify the clinical management of presyncope, ensuring that patients receive appropriate care based on their true risk of adverse events.
Methods
Inclusion Criteria
This systematic review included studies that met the following criteria:
– Population: Adult patients presenting with either presyncope or syncope in an emergency department (ED) setting.
– Study Design: Both observational and interventional studies were considered.
– Outcome Reporting: Studies must have specifically reported outcomes for patients with presyncope.
– Language: Only articles published in English were included in the review, based on evidence indicating that the exclusion of non-English studies does not significantly affect the generalizability of the results.
– Publication Type: Peer-reviewed journal articles were considered for inclusion.
Exclusion Criteria
Studies were excluded from this review based on the following criteria:
– Population: Studies focusing on patients with conditions other than presyncope or syncope, such as hypoglycemia, seizures, or stroke, were excluded.
– Outcome Reporting: Studies that did not report outcomes specifically for presyncope patients were excluded.
– Language: Articles not published in English were excluded.
– Publication Type: Non–peer-reviewed articles, letters to the editor, case reports, and studies where full-text articles were unobtainable despite attempts to contact corresponding authors were excluded from the review.
– Data Availability: Studies were excluded if the required data could not be retrieved from the corresponding authors after at least two attempts.
Study Selection
Following the inclusion and exclusion criteria, the review incorporated both observational and interventional studies that involved adult patients presenting with presyncope or syncope in the ED and reported specific outcomes for presyncope patients. A thorough search of databases, including Ovid MEDLINE, Embase, Scopus, and Web of Science, was conducted from inception to July 2023. Additionally, the reference lists of the included studies were reviewed for further relevant literature. Studies were excluded if the full text could not be obtained or if the necessary data were not available even after reaching out to the corresponding authors.
Search Strategy
The search strategy was developed by a medical librarian experienced in systematic reviews. The strategy incorporated a broad range of keywords related to syncope, presyncope, emergency department, and outcomes. This comprehensive approach was adopted to ensure that studies reporting presyncope outcomes, even as a subset of syncope studies, were captured in the review.
Data Collection and Processing
Two reviewers (HM and KG) independently screened the titles and abstracts of all identified articles to select those for full-text review. Any disagreements during this process were resolved by consulting a third reviewer (VT). Data extraction focused on critical information such as study design, patient demographics, inclusion and exclusion criteria, and reported outcomes. The quality of the studies was assessed using the SIGN 50 tool, which evaluates bias across multiple domains. Studies were then rated as high quality, acceptable, or unacceptable based on their level of bias and the strength of evidence provided.
Analysis
In this study, we provide point estimates for outcomes along with their corresponding 95% confidence intervals (CI), utilizing the margin of error for proportions. Due to the heterogeneity observed in the clinical populations and outcomes, a meta-analysis was not feasible. Therefore, we conducted a descriptive analysis of our findings, which are visually represented in a Forest plot.
Results
We identified 1,880 articles through our search strategy, excluding duplicates. Title and abstract screenings were conducted by HM and KG. We reached out to the authors of six abstracts for additional information; four provided full-text articles, while two confirmed that their studies were never published. After screening, 32 articles were selected for full-text review. Among these, four articles were duplicates and already included for full-text review. At this stage, we excluded 26 articles: 21 did not report outcomes among presyncope patients, and five involved non-ED presyncope patients. Of the six remaining articles, two reported outcomes from the same patient cohort, so only one was included, leaving a total of five studies for the systematic review.
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These five studies, consisting of one retrospective and four prospective designs, were published between 2009 and 2019 and examined the prevalence of serious outcomes among 2,741 ED patients presenting with presyncope. Two studies exclusively enrolled older patients (age > 60 years), while the remaining studies included all adult patients.
Quality and risk-of-bias assessments for all articles were conducted using the SIGN 50 tool. Although some studies exhibited potential bias, they were generally of acceptable quality and met most criteria. Two studies did not compare outcomes between presyncope and syncope patients, making the comparison domain inapplicable. Furthermore, outcomes both during and after ED discharge were reported, and domains related to blinding and outcome assessment were not applicable.
Certain limitations in individual studies are noteworthy. The retrospective study by Sun et al. carries the risk of inclusion bias, as presyncope can be challenging to diagnose even in prospective settings. Grossman et al. and Greve et al. included outcomes unrelated to presyncope, such as renal failure and carotid stroke. In Bastani et al.’s study, nearly half of the patients declined participation, leading to potential sampling bias. Greve et al. conducted a single-center study, while Thiruganasambandamoorthy et al. carried out a two-center study.
Two studies reported inter-rater agreement (kappa statistic) between emergency physicians for identifying presyncope: Thiruganasambandamoorthy et al. reported a kappa of 0.88, and Greve et al. reported a kappa of 0.77. Two studies also reported physicians’ gestalt for the risk of serious outcomes post-ED management. One study categorized patients into vasovagal, orthostatic hypotension, cardiac, and unknown groups, with similar 30-day serious outcomes (1%-2%) across all groups. Bastani et al. noted that physicians perceived lower risk in presyncope patients compared to syncope, though the observed serious outcomes were similar in both groups.
All included studies evaluated short-term (30-day) outcomes, with only one study reporting serious outcomes at six months. Three studies utilized standardized syncope reporting guidelines for outcome reporting. Thiruganasambandamoorthy et al. defined “other outcomes” to capture serious conditions not identified in the syncope guideline. Across the studies, 30-day serious outcomes ranged from 4.4% to 26.8%, with cardiac events being more prevalent than non-cardiac ones. Arrhythmias were the most frequent serious outcome, with subtypes including supraventricular tachycardia, sinus node dysfunction, new or uncontrolled atrial fibrillation, and ventricular arrhythmias. Anemia/hemorrhage was the second most common outcome, followed by myocardial infarction among older patients. Due to heterogeneity in study designs and conflicting inclusion and exclusion criteria, data pooling was not performed. One study, reporting on outcomes at six months, found that 26.8% of presyncope patients experienced serious outcomes, with 5% mortality during this period.
Conclusion
In conclusion, this systematic review highlights the variability in short-term serious outcomes among ED patients presenting with presyncope. While arrhythmias were the most common adverse events, other significant outcomes such as anemia/hemorrhage and myocardial infarction were also prevalent, particularly in older patients. The studies reviewed demonstrated a wide range of outcome frequencies, emphasizing the need for more standardized approaches in reporting and managing presyncope. Further research is necessary to better understand the risks and improve care for presyncope patients in emergency settings.
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