Download Syncope - Review of the Literature October 2011 Syncope Clinical

Syncope - Review of the Literature
October 2011
Syncope Clinical Decision Rules
San Francisco Syncope Rule
Derivation of the San Francisco Syncope Rule to Predict Patients with Short-Term
Serious Outcomes. Quinn JV, Stiell IG, McDermott DA et al. Annals of Emergency
Medicine 43:2 February 2004.
-Prospective cohort study
-Derivation of decision rule to predict serious adverse outcomes at 7 days.
-Serious adverse outcomes defined as death, MI, arrhythmia, PE, stroke, SAH,
significant hemorrhage, or any condition causing or likely to cause a return ED visit
and hospitalization for a related event
-694 patients, 79 developed serious outcomes,
-Of 50 variables, 5 were chosen to form the San Francisco Syncope Rule:
1. Abnormal ECG (not sinus, new changes on ECG)
2. Complaint of SOB
3. Hematocrit <30%
4. Triage SBP <90
5. Hx of CHF
-Rule had sensitivity of 96%, specificity of 62%. Classified 45% of patients as high
risk. If applied for admission, could have reduced admission from 55% to 45%.
-Pnemonic CHESS (CHF, Hematocrit, ECG, SOB, SBP)
-Missed 3 patients with serious outcomes (could have reached 100% sensitivity if
included age >75, but would reduced specificity to 44%)
-Encouraged physicians to use as a risk stratification rule to aid in decision making,
not to replace clinical judgment.
Prospective Validation of the San Francisco Syncope Rule to Predict Patients With
Serious Outcomes. Quinn JV, Stiell IG, McDermott DA et al. Annals of Emergency
Medicine. 47:5 May 2006.
-Extended follow-up to 30 days, and expanded serious outcomes to include anemia
requiring transfusion
-791 visits, 108 serious outcomes
-Rule 98% sensitive, 56% specific. Missed 1 patient, a 54 yo male with DM who
returned for vertebral artery stent.
-Classified 52% as high risk. Could have reduced admissions by 7%. If applied to
only those admitted could have reduced admissions by 24%.
-Encouraged physicians to use as a risk stratification rule to aid in decision making,
not to replace clinical judgment.
External Validation of the San Francisco Syncope Rule in the Canadian Setting.
Thirunganasambandamoorthy V, Hess EP, Alreesi A, et al including Stiell IG. Annals
of Emergency Medicine. 55:5 May 2010.
-SFSR did not fair well in other US validation studies compared to the original
studies. This study set out to evaluate in the Canadian setting. This was the largest
validation study outside the US, and the second largest validation study total.
Worldwide validation studies ranged from sensitivity 69-90%+one 100%, and
specificity of 38-57%.
-Single-centre health records review. Urban Ottawa.
-Looked at 30-day significant serious outcomes.
-505 visits, 49 serious outcomes.
-Rule 90% sensitive, 33% specific. Missed 5 outcomes. 4 occurred in the ED, 1
occurred outside. 3 of the 4 were arrhythmias caught by cardiac monitoring.
Including cardiac monitoring would have increased sensitivity to 96%. Baseline
admission rate was 12%, implementing the rule would have increased admission to
70%.
-Practice pattern in the study missed 30% of serious outcomes outside the ED
Boston Syncope Rule
Predicting Adverse Outcomes in Syncope. Grossman SA, Fischer C, Lipsitz LA, et al.
The Journal of Emergency Medicine. 33:3 January 2007.
-Prospective cohort study, developed rule with 8 criteria:
1. Signs and symptoms of ACS
2. Signs of conduction disease
3. Worrisome cardiac history
4. Valvular heart disease by history or physical
5. Family history of sudden death
6. Persistent abnormal vital signs in ED
7. Volume depletion such as persistent dehydration, GI bleeding, or hematocrit
<30%.
8. Primary CNS event
-Outcomes at 30 days death, PE, CVA, sepsis, arrhythmias, intracranial bleed,
hemorrhage, MI, cardiac arrest, life-threatening sequelae of syncope.
-362 patients, 20% lost to follow up. 68 serious outcomes.
-Sensitivity 97%, specificity of 62%. Missed 2 patients (who went on to have
bradycardia and SVT). Reduction in admissions by 48%.
-Note that in the US, syncope admissions are really high (50-60% compared to 1015% in Canada). Questions arise whether application of these rules in Canada,
which will increase the admission rates, will overburden the system.
STePS
Short and Long Term Prognosis of Syncope, Risk Factors, and Role of Hospital
Admission: Results from the STePS (Short-Term Prognosis of Syncope) Study.
Constantino G, Perego F, Dipaola F et al. Journal of the American College of
Cardiology. 51:3 January 2008.
-Prospective study, looked at outcomes at 10 days and 1 year. Attempted to analyze
predictors, and determine whether hospital admission affected prognosis.
-Serious outcomes were death, need for a major therapeutic procedure, and early
readmission within 10 days to hospital.
-Specific defined abnormal ECG criteria.
-676 patients, 6 lost to follow-up. Admission rate of 33%.
-41 patients had severe outcomes within 10 days. Risk factors for short term
outcomes were: Age >65, male, structural heart disease at presentation, heart
failure, COPD, trauma, abnormal ECG, absence of preceding symptoms.
-Long term: 62 serious outcomes including 40 deaths. Risk factors were age >65,
history of HTN, structural heart disease, heart failure, ventricular arrhythmias,
cerebrovascular disease, COPD, neoplasms, and abnormal ECG.
-Serious outcomes and mortality was greater both in short and long term in patients
who were admitted to hospital. In fact, this turned out to be the worst
prognosticator when compared to all the risk factors.
-In the short term, rate of therapeutic procedures was greater in admitted patients
than in discharged patients, which was interpreted as a potentially favorable effect
from admission on short-term clinical outcome. All patients who underwent a
therapeutic procedure were subsequently discharged. However, is the therapeutic
intervention helpful, or does being in hospital increase the chance that someone will
decide to do something to you. Therapeutic procedures were assumed, not proven,
to save lives.
-Long term mortality was worse for those hospitalized than those not, interpreted
as indications that hospitalization is unlikely to modify long term risk.
OESIL
-Italian study 2003, validated 2005. Rule used ECG, age >65, Hx of cardiac disease,
and no prodrome. Adverse outcomes were death from any cause at 12 months
derivation, 6 months validation. Not entirely useful for admission criteria.
The ECG
The Electrocardiogram in the patient with syncope. Dovgalyuk J, et al. The
American Journal of Emergency Medicine. 25, 688-701. 2007
-Multiple studies have found abnormal ECG indicates increased risk of serious
outcome.
-ECG can provide diagnosis for syncope in: bradycardia, AV block, intraventricular
conduction abnormality, tachydysrhythmias. ACS
-Diagnosis and increased risk of sudden death in: Ventricular preexcitation (WPW),
Brugada, prolonged QT, HCM.
Guidelines/Clinical Policies
Clinical Policy: Critical Issues in the Evaluation and Management of Adult Patients
Presenting to the Emergency Department with Syncope. Annals of Emergency
Medicine. 49:4 April 2007.
-Literature review 1998-2005
1. What history and physical examination data help to risk-stratify patients with
syncope?
-Level A – findings consistent with heart failure put patients at higher risk
-Level B – Older age, structural heart disease, hx of CAD are risk factors
-Level B – Younger age with non-exertional syncope, absence of signs of all of
cardiovascular disease, family history of sudden death, and comorbidities are at low
risk
-Orthostatic BP (systolic BP greater than 20mmHG) can be better assessed by
orthostatic symptoms. Changes are present in 40% of asymptomatic patients >70
years, and 23% of those <60 years. Most people don’t measure it properly.
-Murmurs indicative of valvular dysfunction need investigating.
-Tongue biting is highly specific for convulsive seizures, but poor sensitivity.
-Head trauma with syncope has no increased short term adverse outcome, but dose
place patient in higher 1 year mortality risk category.
-Abdominal exam is important for GI bleeds, rectal exam is necessary if physician
suspects GI bleed.
2. What diagnostic testing data help to risk stratify patients with syncope?
-Level A – ECG (yield low <5% but important)
-Level C – Do not have to echo and CT people unless guided by specific exam
findings
-Lab testing rarely gives a diagnosis, but hematocrit <30% is a risk factor for serious
outcome
3. Who should be admitted after syncope?
-Different in Canada vs. the US where litigation is a major factor
-Level B – admit patients with evidence of heart failure or structural heart disease
-Level B – admit patients with other factors that lead to stratification as high risk for
adverse outcomes. Defined as: Older age and associated comorbidities, abnormal
ECG, Hct <30%, history of CHF, CAD, or structural heart disease.
-Primary reason for admission should be that the physician feels the patient’s risk
assessment puts the patient at high risk for a dysrhythmia or sudden death, and that
observation might detect that event and enable an intervention.
-Problem is, how long to admit for?
-SFSR is the only study evaluating patients at 7 days.
Accuracy and Quality of Clinical Decision Rules for Syncope in the Emergency
Department: A Systematic Review and Meta-analysis. Serrano et al. Annals of
Emergency Medicine. 56:4 October 2010.
-Pretty thorough systematic review, assigned Levels 1-4. 1 good, 4 bad.
-Meta-analysis was restricted to individual decision rules.
-Level 2 = rules that can be used in various settings with confidence in there
accuracy
-Only 2 rules met Level 2 : SFSR (1 derivation 7 validations), and OESIL (1 der, 2 val)
-Remainder met Level 4 criteria, ie. Not useful.
-SFSR meta-analysis suggested Sensitivity 87%, specificity 48%.
-No statistical significant explanation for variable performance of SFSR, study design
(prospective vs. retrospective) and ECG interpretation approached statistical
significance. Noted that small study numbers limited this result.
-Interestingly, rule performed better when ECG analyzed by ER physician than
cardiologist, probably because cardiologist picked up more subtle differences to
label ECG as abnormal.
-SFSR is the best short-term risk assessment tool we have, but: “All the clinical
prediction guides included in the review need further development before they can
be routinely used in clinical practice.”
Standardized Approaches to the Investigation of Syncope: Canadian Cardiovascular
Society Position Paper. Robert Sheldon (Calgary), and Richard Leather (my Victoria
neighbour). Canadian Journal of Cardiology 27, 2011.
-0.7% die in 7-30 days, 10% die within 1 year
-7.5% nonfatal severe outcome in the ED, another 4.5% within 7-30 days.
-Only half of theses are for cardiovascular disorders
-Arbitrarily defined major risk factors and minor risk factors
Major: Abnormal ECG, hx of cardiac disease, hypotension, CHF past or present
Minor: Age >60 years, dyspnea, anemia (hct <0.3), hypertension, cerebrovascular
disease, family hx of early sudden death <50years), specific situations (sycope while
supine, during exercise, or with no prodrome)
-Patients with major risk factors should have urgent cardiac assessment within 2
weeks. (Strong recommendation, low-quality evidence)
-Although ED syncope rules may have prognostic value, there is no evidence that
they improve diagnostic accuracy or reduce costs, the may increase costs
substantially (Weak Recommendation, Very Low-Quality Evidence)
-Noted 1 study had physician judgement = SFSR. But if you don’t trust your
judgement…
-Formal syncope units might increase diagnostic specificity or sensitivity and reduce
costs (Weak Recommendation, Low-Quality evidence)
-Recommendations on what to do. Hx, physical, ecg, and utilize other investigations
with clinical suspicion. (They include orthostatic BP measurements)
-CT should be done only for focal neurological signs, symptoms of seizure activity, or
to rule out hemorrhage in trauma.
-Standardized diagnostic testing pathways may improve efficiency and reduce
unnecessary testing. These pathways require access to a specialist, and an online
prompting tool.
Driving and Syncope
CCMTA Medical Standards for Drivers. March 2009
www.ccmta.ca