Studied variables
We documented temporal data, demographic characteristics (sex, age,
race), clinical presentation (signs and symptoms), setting (Emergency
Department (ED), outpatient clinic, inpatients) and, when available in
electronic medical records, lag time from clinical onset to diagnosis,
previous medical observations and complementary investigation. Patients
admitted with PE symptoms were classified as outpatients, as opposed to
patients who were primarily hospitalized for other reasons, referred to
as inpatients. Imagological exams, including Computed Tomography with
Pulmonary Angiography (CTPA), ventilation-perfusion (VQ) scan, chest
X-ray (CXR), echocardiogram (ECHO), electrocardiogram (ECG)), venous
compressive ultrasound (CUS) with Doppler, and laboratory tests
(D-dimer, troponin I or B-type natriuretic peptide levels) at diagnosis
were registered. Anatomic distribution of the thrombus was classified as
central, lobar, segmental or sub-segmental, according to the most
central segment of the pulmonary arterial tree affected.
Risk stratification followed the American Heart Association’s Scientific
Statement, (17) using age-appropriate reference values for heart rate
and blood pressure. (18) Massive (high risk) PE was defined by the
presence of hypotension, bradycardia or poor peripheral perfusion,
whereas sub-massive (intermediate risk) PE was defined by right
ventricular strain/injury and/or elevated cardiac biomarkers (troponin I
or B-type natriuretic peptide) in non-hypotensive patients. Right
ventricular strain/injury was defined by dilation and/or systolic
dysfunction on ECHO or CTPA or by ECG changes: new complete or
incomplete right bundle – branch block, anteroseptal ST alterations or
T wave inversion. The remaining cases were considered non-massive PE
(low risk).
Associated deep venous thrombosis (DVT), data on thrombophilia testing
and the presence of other underlying risk factors were noted. Obesity
was considered when the body mass index was above the 95th percentile
for age and sex. Therapeutic and support interventions and secondary
prophylaxis were investigated. Outcomes included: PE-related mortality
and all-causes mortality during hospitalization and follow up, recurrent
VTE, chronic PE (persistence of thrombus in the same territory), chronic
thromboembolic pulmonary hypertension (CTPH) and post-thrombotic
syndrome (PST).
Finally, we applied PE risk stratification clinical scores, including
the Wells criteria, the PERC tool and two pediatric
criteria15,16, to our population and evaluated their
sensitivity.