Prognostic value of cardiac biomarkers in the risk stratification of syncope: a systematic review

Little is known about the epidemiology and prognosis of syncope in the general population. We evaluated the incidence, specific causes, and prognosis of syncope among women and men participating in the Framingham Heart Study from 1971 to 1998. Of 7814 study participants followed for an average of 17 years, 822 reported syncope. The incidence of a first report of syncope was 6.2 per 1000 person-years. The most frequently identified causes were vasovagal (21.2 percent), cardiac (9.5 percent), and orthostatic (9.4 percent); for 36.6 percent the cause was unknown. The multivariable-adjusted hazard ratios among participants with syncope from any cause, as compared with those who did not have syncope, were 1.31 (95 percent confidence interval, 1.14 to 1.51) for death from any cause, 1.27 (95 percent confidence interval, 0.99 to 1.64) for myocardial infarction or death from coronary heart disease, and 1.06 (95 percent confidence interval, 0.77 to 1.45) for fatal or nonfatal stroke. The corresponding hazard ratios among participants with cardiac syncope were 2.01 (95 percent confidence interval, 1.48 to 2.73), 2.66 (95 percent confidence interval, 1.69 to 4.19), and 2.01 (95 percent confidence interval, 1.06 to 3.80). Participants with syncope of unknown cause and those with neurologic syncope had increased risks of death from any cause, with multivariable-adjusted hazard ratios of 1.32 (95 percent confidence interval, 1.09 to 1.60) and 1.54 (95 percent confidence interval, 1.12 to 2.12), respectively. There was no increased risk of cardiovascular morbidity or mortality associated with vasovagal (including orthostatic and medication-related) syncope. Persons with cardiac syncope are at increased risk for death from any cause and cardiovascular events, and persons with syncope of unknown cause are at increased risk for death from any cause. Vasovagal syncope appears to have a benign prognosis. Copyright 2002 Massachusetts Medical Society

We sought to assess short- and long-term prognosis of syncope and associated risk factors. Syncope is a common clinical event, but our knowledge of its short-term outcome is largely incomplete. Further, it is unknown whether hospital admission might positively affect a patient's syncope prognosis. We screened 2,775 consecutive subjects who presented for syncope at 4 emergency departments between January and July 2004. Short- and long-term severe outcomes (i.e., death and major therapeutic procedures) and related risk factors were compared in all enrolled patients arrayed according to hospital admission or discharge. A total of 676 subjects were included in the study. Forty-one subjects (6.1%) experienced severe outcomes (5 deaths, 0.7%; 36 major therapeutic procedures, 5.4%) in the 10 days after presentation. An abnormal electrocardiogram, concomitant trauma, absence of symptoms of impending syncope, and male gender were associated with short-term unfavorable outcomes. Long-term severe outcomes were 9.3% (40 deaths, 6.0%; 22 major therapeutic procedures, 3.3%), and their occurrence was correlated with an age >65 years, history of neoplasms, cerebrovascular diseases, structural heart diseases, and ventricular arrhythmias. Short-term major therapeutic procedures were more common (p < 0.05) in subjects who had been admitted to hospital (13.3%) than in discharged (1.6%), whereas mortality was similar. One-year mortality was greater (p < 0.05) in admitted (14.7%) than in discharged (1.8%) patients. Risk factors for short- and long-term adverse outcomes after syncope differed. Hospital admission favorably influenced syncope short term prognosis. Instead, 1-year mortality was unaffected by hospital admission and related to comorbidity.

The aim of this study was to develop and validate a clinical decision rule (CDR) to predict 1-month serious outcome and all-cause death in patients presenting with syncope to the emergency department. Syncope is a common, potentially serious condition accounting for many hospital admissions. This was a single center, prospective, observational study of adults presenting to the emergency department with syncope. A CDR was devised from 550 patients in a derivation cohort and tested in a validation cohort of a further 550 patients. One-month serious outcome or all-cause death occurred in 40 (7.3%) patients in the derivation cohort. Independent predictors were brain natriuretic peptide concentration > or =300 pg/ml (odds ratio [OR]: 7.3), positive fecal occult blood (OR: 13.2), hemoglobin < or =90 g/l (OR: 6.7), oxygen saturation < or =94% (OR: 3.0), and Q-wave on the presenting electrocardiogram (OR: 2.8). One-month serious outcome or all-cause death occurred in 39 (7.1%) patients in the validation cohort. The ROSE (Risk stratification Of Syncope in the Emergency department) rule had a sensitivity and specificity of 87.2% and 65.5%, respectively, and a negative predictive value of 98.5%. An elevated B-type natriuretic peptide (BNP) concentration alone was a major predictor of serious cardiovascular outcomes (8 of 22 events, 36%) and all-cause deaths (8 of 9 deaths, 89%). The ROSE rule has excellent sensitivity and negative predictive value in the identification of high-risk patients with syncope. As a component, BNP seems to be a major predictor of serious cardiovascular outcomes and all-cause death. The ROSE rule and BNP measurement might be valuable risk stratification tools in patients with emergency presentations of syncope and should now be subjected to external validation. Copyright (c) 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.