Syncope paradox in the outcome of patients with pulmonary thromboembolism: short-term and midterm outcome

Major bleeding in patients with pulmonary embolism presenting with syncope

INTRODUCTION

Syncope has been shown to be a risk factor of bleeding in patients receiving thrombolytic therapy for acute pulmonary embolism (PE). Whether syncope predicts bleeding in a broader population of patients with PE remains unknown.

METHODS

We used the RIETE registry data to assess whether initial presentation with syncope could predict bleeding in PE patients receiving anticoagulant therapy, and to explore the association between presence of syncope and timing and site of major bleeding events.

RESULTS

Among 45,765 patients with acute PE from March 2001 to January 2021, 6760 (14.8%) had syncope. Patients with syncope were older and more likely to have hypotension, tachycardia, hypoxaemia or elevated troponin levels than those without syncope. They also were more likely to receive thrombolytics. During the first 90 days, 1097 patients (2.4%) suffered major bleeding (gastrointestinal 335, hematoma 271 and intracranial 163) and 3611 died (158 had fatal bleeding). Patients with syncope had a higher rate of major bleeding (odds ratio [OR]: 1.63; 95% CI: 1.41-1.89) and a nonsignificantly higher rate of fatal bleeding (OR: 1.47; 95% CI: 0.99-2.17) than those without syncope. Multivariable analysis confirmed that patients with syncope were at increased risk for major bleeding (adjusted hazard ratio [aHR]: 1.34; 95% CI: 1.15-1.55). On sensitivity analysis, the increased risk for major bleeding was confirmed in patients initially receiving anticoagulant therapy without thrombolytics at 7 days (aHR: 1.47; 95% CI: 1.13-1.91) and 90 days (aHR: 1.33; 95%CI: 1.13-1.56).

DISCUSSION

Syncope is a predictor of major bleeding events in patients with PE, even among those receiving anticoagulation monotherapy.

Right ventricular strain in patients with pulmonary embolism and syncope

Patients with acute pulmonary embolism (PE) can present with various clinical manifestations including syncope. The mechanism of syncope in PE is not fully elucidated and data of right ventricular (RV) function in patients has been limited. We retrospectively identified 477 consecutive patients hospitalized with acute PE diagnosed with a computed tomogram (CT) who also had a transthoracic echocardiogram (TTE) 24 h prior to or 48 h after diagnosis. Parameters of RV strain on CT, TTE, electrocardiogram (ECG), and clinical characteristics and adverse outcomes were collected. Patients with all three studies available for assessment were included (n = 369) and those with syncope (n = 34) were compared to patients without syncope (n = 335). Patients with syncope were more likely to demonstrate RV strain on all three modes of assessment compared to those without syncope [17 (50%) vs. 67 (20%); p = 0.001], and those patients were more likely to receive advanced therapies [9 (53%) vs. 15 (22%); p = 0.02]. PE-related mortality was highest among those presenting with high-risk PE and syncope (36%, OR 20.1, 95% CI 5.3-81.1; p < 0.001) and was low in patients with syncope without criteria for high-risk PE (3%, OR 1.2, 95% CI 0.2-10.0; p < 0.001). In conclusion, acute PE patients with syncope are more likely to demonstrate multimodality evidence of RV strain and to receive advanced therapies. Syncope was only associated with increased PE-related mortality in patients presenting with a high-risk PE. Syncope alone without evidence of RV strain is associated with low short-term adverse events and is similar to those without syncope.

The Prognostic Value of Syncope on Mortality in Patients With Pulmonary Embolism: A Systematic Review and Meta-analysis

STUDY OBJECTIVE

Syncope is a presenting symptom in 10% to 20% of patients with pulmonary embolism. We perform a meta-analysis to clarify the prognostic value of syncope on short-term mortality in pulmonary embolism patients and its association with hemodynamic instability.

METHODS

PubMed, EMBASE, and the Cochrane Library were searched up until January 7, 2020. Studies reporting inhospital or 30-day mortality of adults with pulmonary embolism with and without syncope were included. Quality of included studies was evaluated with the Quality in Prognosis Studies tool. Meta-analysis was conducted to derive pooled odds ratios (ORs) and risk differences for the relation of syncope with mortality and hemodynamic instability. To study the influence of hemodynamic instability on the association between syncope and mortality, meta-regression was performed.

RESULTS

Search and selection resulted in 26 studies, of which 20 were pooled, involving 9,419 of 335,120 patients (3%) with syncope. Syncope was associated with higher mortality (OR 1.82; 95% confidence interval [CI] 1.14 to 2.90; I2 88%; risk difference 4% [95% CI 1% to 8%]) and higher prevalence of hemodynamic instability (OR 4.36; 95% CI 2.27 to 8.37; I2 93%; risk difference 12% [95% CI 7% to 18%]). OR for mortality in patients with pulmonary embolism with syncope versus without it was higher in the presence of a larger difference in hemodynamic instability between groups (coefficient 0.05; 95% CI 0.01 to 0.09).

CONCLUSION

The association between syncope and short-term mortality in patients with pulmonary embolism is explained by a difference in hemodynamic instability. This emphasizes the importance of risk stratification by hemodynamic status in pulmonary embolism patients with and without syncope.

Presyncope Is Associated with Intensive Care Unit Admission in Emergency Department Patients with Acute Pulmonary Embolism

INTRODUCTION

Syncope is common among emergency department (ED) patients with acute pulmonary embolism (PE) and indicates a higher acuity and worse prognosis than in patients without syncope. Whether presyncope carries the same prognostic implications has not been established. We compared incidence of intensive care unit (ICU) admission in three groups of ED PE patients: those with presyncope; syncope; and neither.

METHODS

This retrospective cohort study included all adults with acute, objectively confirmed PE in 21 community EDs from January 2013-April 2015. We combined electronic health record extraction with manual chart abstraction. We used chi-square test for univariate comparisons and performed multivariate analysis to evaluate associations between presyncope or syncope and ICU admission from the ED, reported as adjusted odds ratios (aOR) with 95% confidence intervals (CI).

RESULTS

Among 2996 PE patients, 82 (2.7%) had presyncope and 109 (3.6%) had syncope. ICU admission was similar between groups (presyncope 18.3% vs syncope 25.7%) and different than their non-syncope counterparts (either 22.5% vs neither 4.7%; p<0.0001). On multivariate analysis, both presyncope and syncope were independently associated with ICU admission, controlling for demographics, higher-risk PE Severity Index (PESI) class, ventilatory support, proximal clot location, and submassive and massive PE classification: presyncope, aOR 2.79 (95% CI, 1.40, 5.56); syncope, aOR 4.44 (95% CI 2.52, 7.80). These associations were only minimally affected when excluding massive PE from the model. There was no significant interaction between either syncope or presyncope and PESI, submassive or massive classification in predicting ICU admission.

CONCLUSION

Presyncope appears to carry similar strength of association with ICU admission as syncope in ED patients with acute PE. If this is confirmed, clinicians evaluating patients with acute PE may benefit from including presyncope in their calculus of risk assessment and site-of-care decision-making.

Differential impact of syncope on the prognosis of patients with acute pulmonary embolism: a systematic review and meta-analysis

Aims

Controversial reports exist in the literature regarding the prognostic role and therapeutic implications of syncope in patients with acute pulmonary embolism (PE). We conducted a systematic review and meta-analysis to investigate the association between syncope and short-term adverse outcomes, taking into account the presence or absence of haemodynamic compromise at acute PE presentation.

Methods and results

The literature search identified 1664 studies, 29 of which were included for a total of 21 956 patients with PE (n = 3706 with syncope). Syncope was associated with higher prevalence of haemodynamic instability [odds ratio (OR) 3.50; 95% confidence interval (CI) 2.67-4.58], as well as with echocardiographic signs of right ventricular (RV) dysfunction (OR 2.10; CI 1.60-2.77) at presentation. Patients with syncope had a higher risks of all-cause early (either in-hospital or within 30 days) death (OR 1.73; CI 1.22-2.47) and PE-related 30-day adverse outcomes (OR 2.00; CI 1.11-3.60). The absolute risk difference (95% CI) for all-cause death was +6% (+1% to +10%) in studies including unselected patients, but it was -1% (-2% to +1%) in studies restricted to normotensive patients. We observed no prognostic impact of syncope in studies with a lower score at formal quality assessment and in those conducted retrospectively.

Conclusion

Syncope as a manifestation of acute PE was associated with a higher prevalence of haemodynamic instability and RV dysfunction at presentation, and an elevated risk for early PE-related adverse outcomes. The association with an increased risk of early death appeared more prominent in studies including unselected patients, when compared with those focusing on normotensive patients only.

Prospective Study of Pulmonary Embolism Presenting as Syncope

BACKGROUND

Syncope represents a common condition among the general population. It is also a frequent complaint of patients in the emergency department (ED). Pulmonary embolism (PE) considers a differential diagnosis, particularly in a case of syncope without chest pain.

STUDY QUESTION

What is the prevalence of PE among patients who presented an episode of syncope to the ED and among those hospitalized for syncope in a tertiary care hospital?

STUDY DESIGN

From January 2012 to December 2017, we conducted a prospective observational study among adult patients presenting themselves to the ED consecutively or admitted for syncope.

MEASURES AND OUTCOMES

Syncope and PE were defined by professional guidelines. PE was ruled out in patients who had a low pretest clinical probability, as per Wells score and a negative D-dimer assay. In other patients, computed tomography pulmonary angiography was performed.

RESULTS

Seventeen thousand eight-two patients (mean age 71.3 ± 13.24 years) visited the ED for syncope. PE was detected in 45 patients (mean age 65.75 ± 9.45 years): 4 with low risk, 26 with intermediate risk, and 15 with high risk. The prevalence of PE in those hospitalized with syncope was 11.47%, which is 45 of 392 (confidence interval 95% 8.48-15.04), and was 2.52%, 45 of 1782 (confidence interval 95% 1.8-3.3), in patients presenting with syncope to the ED. The location of the embolus was bilateral in 24 patients (53.33%), in a main pulmonary artery in 10 (22.22%), in a lobar artery in 10 (22.22%), and in a segmental artery in 1 (2.22%).

CONCLUSIONS

The occurrence of syncope, if not explained otherwise, should alert one to consider PE as a differential diagnosis. PE rate, presenting as syncope, is the highest in patients with large thrombi, which is responsible for bilateral or proximal obstruction in a main or lobar pulmonary artery.

Does Syncope Predict Mortality in Patients With Acute Pulmonary Embolism? A Retrospective Review

Background

Acute pulmonary embolism (APE) is a potentially fatal disease with high mortality. Prior studies have shown an increased frequency of central localization of the clot, right ventricular dysfunction and elevated troponin in patients who present with syncope and APE. Existing evidence regarding mortality and length of hospital stay in these patients is unclear.

Methods

We retrospectively reviewed electronic medical records of patients who were admitted in a tertiary care hospital in rural Upstate New York and diagnosed with APE from July 2014 to July 2016. Two hundred nineteen patients were reviewed in two groups: patients who presented with syncope and those without syncope.

Results

The prevalence of syncope was found to be 6.8% (15/219). Hypotension on admission was more common among patients with syncope compared to no syncope (26.7% and 7.4%, respectively, P = 0.03). A clinically significant difference was found in 30-day mortality among those with syncope versus no syncope (21.3% vs. 7.4%, P = 0.096). No significant difference was found in length of stay (mean 6.7 days in patients with syncope vs. 6.4 without syncope, P = 0.783), central localization (26.7% with syncope vs. 43.2% without syncope, P = 0.21) or troponin elevation (46.2% in patients with syncope vs. 27.9% without syncope, P = 0.205). On multivariable analysis, hypotension was significantly higher among those with syncope (odds ratio: 5.23, P = 0.0148).

Conclusion

This study suggests 30-day mortality may be higher among patients with syncope. It is important to risk stratify patients on admission in order to reduce mortality and morbidity associated with lethal disease.

Syncope as a presentation of acute pulmonary embolism

PURPOSE

Syncope is an atypical presentation for acute pulmonary embolism (APE). There are conflicting data concerning syncope and prognosis of APE.

PATIENTS AND METHODS

One hundred and seventy-nine consecutive patients aged 22-96 years (median, 68 years) with APE were retrospectively enrolled in the study.

RESULTS

Prevalence of syncope was 13% (n=23) at the time of presentation. Compared to patients without syncope, those with syncope had a higher rate of central embolism (83% vs 43%, respectively, P=0.002), right ventricular dysfunction (91% vs 68%, P=0.021), and troponin positivity (80% vs 39%, P=0.001) but not 30-day mortality (13% vs 10%, P=0.716). Multivariate analysis showed that central localization (odds ratio: 9.08) and cardiac troponin positivity (odds ratio: 4.67) were the independent correlates of the presence of syncope in the patients with APE. Frequency of cardiopulmonary disease was lower, and duration from symptom onset to hospital admission was shorter in patients with syncope (P=0.138 and 0.118, respectively), although not significant.

CONCLUSION

Syncope most likely represents an intermediate condition between massive APE and hypotension. In APE patients with syncope, the prognosis seems to depend on the underlying pathology, the patient's age, comorbidities and duration from symptom onset to hospital admission, and the use of thrombolytic therapy.