Pulmonary Embolism May Be An Overlooked Cause of Syncope

MedicalResearch.com Interview with:

Paolo Prandoni, M.D., Ph.D.

Dr.Paolo Prandoni

Paolo Prandoni, M.D., Ph.D. and
Department of Cardiovascular Sciences
Vascular Medicine Unit
University of Padua, Padua

Sofia Barbar, M.D

Dr.Sofia Barbar

Sofia Barbar, M.D
Department of Internal and Emergency Medicine
Civic Hospital of Camposampiero

MedicalResearch.com: WhaWhat are the main findings?

Response: Syncope is defined as a sudden loss of consciousness due to transient global cerebral hypoperfusion characterized by rapid onset, short duration, and spontaneous complete recovery. According to the most recent guidelines, syncope can be classified as neurally-mediated, due to orthostatic hypotension and cardiovascular. Syncope is frequent in general population and represents up to 2% of all attendances in Emergency Department in Europe. The initial approach is unable to identify a plausible cause for syncope in 25-30% of cases and approximately 40% of syncope referred to an Emergency Department is then admitted to the hospital.

Pulmonary embolism (PE) is an obstruction in the pulmonary arteries interfering with both blood circulation and gas exchange and therefore representing a potentially life-threatening event. Clinical features of PE are extremely variable.

Available guidelines on syncope management consider PE as an infrequent cardiovascular cause of syncope. However, the true prevalence of pulmonary embolism in syncope-patients it is actually unknown. Moreover a workup for PE diagnosis in these patients is not suggested in the current guidelines.

MedicalResearch.com: What are the main findings?

Response: In our study, patients admitted in a Medical Ward for a first episode of syncope underwent a systematic work-up for the diagnosis of  pulmonary embolism, regardless the presence of other possible explanations for syncope. In patients with a low pre-test probability (according to Well’s score) and a negative D-dimer,  pulmonary embolism was ruled out. All other patients underwent a confirmatory diagnostic test (i.e. CT lung scan or V/Q lung scan). PE was identified in 97/560 patients, with a prevalence of 17.3% in the whole cohort and of 25.4% (52/205) in patients with apparently unexplained syncope. In approximately 60% of the patients with PE, the embolus involved a main pulmonary/lobar artery or perfusion defects interested more than 25% of the total area of both lungs, thus justifying an abrupt vascular obstruction and a consequent sudden loss of consciousness.

MedicalResearch.com: What should readers take away from your report?

Response: Pulmonary embolism, in selected patients, could be the underlying cause of syncope in a considerable proportion of cases (nearly one every six patients). In old patients presenting with syncope – especially when an alternative explanation is not found – the attending physician, in medical wards, should consider pulmonary embolism as a possible differential diagnosis. Interestingly, pulmonary embolism is a frequent cause of syncope in patients who had a possible alternative explanation of syncope, but its prevalence is not trivial in patients who did not.

The results of our study should increase the awareness of physicians about the high prevalence of PE in patients hospitalized for a first episode of syncope. An approach based on international accepted diagnostic algorithms is useful for the identification of syncope related to a possible underlying life-threatening complication like pulmonary embolism.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Response: Future research in this field should aim to find a clinical tool more accurate in the identification of those patients with PE-related syncope both in Medical Wards and, possibly, in the Emergency Department.

Moreover, it could be very interesting a connection with basic research, in order to clarify the mechanisms linking pulmonary embolism and the occurrence of syncope, also in those cases with an incomplete obstruction of pulmonary arteries.

MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.


Prevalence of Pulmonary Embolism among Patients Hospitalized for Syncope
Paolo Prandoni, M.D., Ph.D., Anthonie W.A. Lensing, M.D., Ph.D., Martin H. Prins, M.D., Ph.D., Maurizio Ciammaichella, M.D., Marica Perlati, M.D., Nicola Mumoli, M.D., Eugenio Bucherini, M.D., Adriana Visonà, M.D., Carlo Bova, M.D., Davide Imberti, M.D., Stefano Campostrini, Ph.D., and Sofia Barbar, M.D., for the PESIT Investigators*
N Engl J Med 2016; 375:1524-1531
October 20, 2016

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Last Updated on October 24, 2016 by Marie Benz MD FAAD