first episode of syncope, should we do workup for Pulmonary embolism well simplified criteria D dimer level CT angiogram ventilation perfusion scanning

1. Presented in Journal club by Dr Fakhir Raza Haidri
Specialist MICU
1st November 2016

2. Introduction
• Syncope: Defined as
a transient loss of consciousness that has a rapid onset, short duration
(in current study less than 1 minute), and spontaneous resolution and
is believed to be caused by temporary cerebral hypoperfusion
Eur Heart J. 2009 Nov;30(21):2631-71. doi: 10.1093/eurheartj/ehp298. Epub 2009 Aug 27

3. Flow chart of Syncopal Attack
Eur Heart J. 2009 Nov; 30(21): 2631–2671.

4. Pathophysiology
Eur Heart J. 2009 Nov; 30(21): 2631–2671.

5. Background
• The prevalence of pulmonary embolism among patients hospitalized
for syncope is not well documented, and current guidelines pay little
attention to a diagnostic workup for pulmonary embolism in these
patients.

6. Question
• Do All Patients with 1st Time Syncope need a Pulmonary Embolism
Workup?
• Outcome measure: Prevalence of Pulmonary Embolism among
Patients with a First Episode of Syncope

7. Methods
• Cross sectional study
• older than 18 years of age
• first episode of syncope
• Definition of syncope used: Syncope was defined as a transient loss of
consciousness with rapid onset, short duration (i.e., <1 minute), and
spontaneous resolution, with obvious causes such as epileptic
seizure, stroke, and head trauma ruled out

8. Exclusion criteria
• Previous Episodes of Syncope
• On Anticoagulation Therapy
• Pregnant
• Did Not Provide Informed Consent

9. Method
• 2584 patients with first-time syncope were screened in 11 Italian
emergency departments – 9 of which were non-academic
• 72% of these patients were discharged home based on a clinical
evaluation by a physician in the emergency department
• 717 patients were admitted to the hospital
• 157 were excluded for the following reasons: 118 were receiving
anticoagulation therapy, 82 had atrial fibrillation, 36 had other
reasons, 35 had recurrent syncope, 4 declined to participate.
• So 560 inpatients were then all evaluated for pulmonary embolus.

10. Following criteria applied in 560 patients

12. Summary of Patients in the study

13. Thrombotic Burden
• CT finding Among the 72 patients in whom PE confirmed
• Main pulmonary artery in 30 patients (41.7%),
• Lobar artery in 18 patients (25.0%),
• Segmental artery in 19 patients (26.4%),
• Subsegmental artery in 5 patients (6.9%).

14. Thrombotic Burden
• VQ finding in 24 patients
• Perfusion defect involved more than 50% of the area of both lungs in
4 patients
• 26 to 50% of the area of both lungs in 8 patients
• 1 to 25% of the area of both lungs in the remaining 12 patients
• In the 1 patient who died, pulmonary embolism involved both main
pulmonary arteries.

15. Clinical symptoms in confirmed PE patients
• Tachypnea: 45.4% vs. 7.1%
• Tachycardia: 33.0% vs. 16.2%
• Hypotension: 36.1% vs. 22.9%
• clinical signs or symptoms of deep-vein thrombosis: 40.2% vs. 4.5%
previous venous thromboembolism: 11.3% vs. 4.3%
• Active cancer 19.6% vs. 9.9%
• No clinical manifestations 24.7%

16. Conclusion
• Among patients who were hospitalized for a first episode of syncope
and who were not receiving anticoagulation therapy, pulmonary
embolism was confirmed in 17.3% (approximately one of every six
patients).
• The rate of pulmonary embolism was highest among those who did
not have an alternative explanation for syncope

17. Discussion
Patient Population or Problem:
Intervention (or Exposure): Which medical event or therapy do you
need to study the effect of? NON INTERVENTIONAL
Comparison (if known): With what will you compare the
intervention's results? NO COMPARISON
Outcomes: What are the relevant effects (outcomes) you'll be
monitoring? IT WAS CROSS SECTIONAL STUDY, PATIENTS NOT
FOLLOWED, MORTALITY NOT ASSESSED

18. Strengths
• Multi center study
• Presence or absence of PE assessed with a validated algorithm based
on pretest clinical probability

19. Limitations (weaknesses)
• Hugely biased selection of patients (None of the discharged patients
included)
• A specific syncope workup was not mandated by all hospitals involved
in the study
• Imaging for PE was only performed in patients with an elevated D-
Dimer and/or had a high pretest probability for PE
• Confirmation of DVT in symptomatic patients was also not mandated

20. Limitations (weaknesses)
• Search for other causes of syncope was left to the discretion of the
physician, meaning other causes of syncope may have been under
reported
• No information was collected on treatment and follow-up of patients;
therefore, we don’t know what the clinical outcomes of these
patients was
• Imaging to confirm PE was not done at admission, but up to 48 hours
after admission. Immobility during hospitalization is a known to cause
VTE

21. Other points in discussion
• Authors conclusion of PE confirmation in approximately one in every
six patients (17.3%) however these numbers are grossly inflated. 2427
patients were actually included in this study (157 were excluded).
Excluding all patients will overestimate the results, as was done in this
study
• 97 patients had PE confirmed so instead of 97/230 (42.2%) the
number should be 97/2427 (3.9%)
• To take this one step further…if you exclude subsegmental PEs (i.e.
Unclear clinical significance) the number is actually 80/2427 (3.2%)