RESULTS
During the 13-years period, we registered 29 episodes of PE in 27 patients, with an average of 2.2 episodes per year, corresponding to 9.52 per 10.000 admissions. All the patients were Caucasian, with a mean age of 14.1 ± 4.3 years and 17 (62.9%) were female (Table 1). Twenty-four patients (88.9%) were adolescents.
One patient presented as a sudden death and autopsy revealed PE, but no further data was possible to obtain. Twenty episodes occurred in patients admitted for PE symptoms (outpatients), 18 from the ED and two from the outpatient clinic. Thirteen (65%) were female and all were teenagers (mean age 16.0 ± 0,86 years). In this group, the most frequent presentations were thoracalgia (15/20, 75%), dyspnea (14/20, 70%), DVT (8/20, 40%) and syncope (6/20, 30%). Other symptoms included fever (4/20, 20%), anxiety (2/20, 10%), palpitations (1/20, 5%) and hemoptysis (1/20, 5%). Thirteen patients were tachycardic (13/20, 65%) and eight hypoxemic (8/20, 40%). In 10 of these patients, the diagnosis was not established during previous medical examinations that had taken place before admission, and five had been submitted to complementary exams, including CXR, blood analysis and ECG, described as normal. Respiratory infections (2/10, 20%), asthma flare (1/10, (10%)) and anxiety (2/10, 20%) had been the main alternative diagnosis assumed. Mean time lag from presentation to diagnosis was 4.8 days (range 0-42 days). All patients had at least one risk factor (average 1.55) identifiable in clinical history, including oral contraception (13/20, 65%), positive family history (4/20, 20%), obesity (4/20, 20%), immunomediated disorders (4/20, 20%). and thrombophilia history (protein S deficiency) (1/20, 5%). Further investigation revealed seven inherited thrombophilia (7/20, 35%) and two vascular anomalies (May-Turner Syndrome) (2/20, 10%).
In the inpatient group (n=8), mean age was 9.49 ± 6.14 years, and 63% (5/8) were male. Clinical presentation included respiratory failure (4/8, 50%), hemodynamic compromise (2/8, 25%) and hemoptysis (1/8, 12.5%). Three PE (10.7%) were asymptomatic, corresponding to imagological findings discovered during the investigation of underlying pathologies (Table 2). Infections (6/8, 75%), reduced mobility (6/8, 75%), the presence of a central venous catheter (CVC) (5/8, 62.5%) and complex chronic conditions (5/8, 62.5%), such as congenital heart disease, oncologic or neurologic conditions, were the main risk factors for PE in the inpatient group.
Details in complementary exams are displayed in Table 3. The diagnosis was confirmed by CTPA in 82.1% PE (23/28). Nineteen emboli (67.9%) had a central location. D-dimer assays were positive in all acute PE, not being performed in three cases: two asymptomatic PE and in a severely ill patient, in whom CTPA was directly performed. Most PE were non-massive (46.4%, 13/28), 39.3% (11/28) were submassive and 14.3% (4/28) were massive (Table 4). Tachycardia was more prevalent in submassive and massive groups (p = 0.06) and didn´t correlate with PE-mortality (p=0.519). There were two intra-cardiac thrombi, in children with complex congenital cardiopathy. Twelve CXR were performed and were normal in 83.3% of the cases (10/12). Pneumomediastinum (n=1) and pleural effusions (n=2) were concomitantly described.
The application of the Wells criteria, assuming that an alternative diagnosis was less likely except in asymptomatic cases, classified 71.4% (20/28) of our PE patients as high risk. The further D-dimer testing recommended to the lower risk patients were positive, and thus, would recommend performing CTPA in all but one (asymptomatic) PE (sensitivity 96%). Application of the PERC criteria correctly classified 26 patients as PE, except two asymptomatic (sensitivity 92.9%). Hennelly’s et al. pediatric PE model application misclassified four of our patients as non-risk (sensitivity 85.7%) (two asymptomatic), and Lee´s et al. model missed two PE, one asymptomatic (sensitivity 92.9%).
Two patients with intracardiac thrombi underwent surgical thrombectomy. Fibrinolysis with recombinant tissue plasminogen activator (alteplase) was performed due to significant right ventricular dysfunction in four patients, two with hemodynamic instability (massive PE). Anticoagulation therapy was initiated in all but one patient, due to major simultaneous hemorrhages. Unfractioned Heparin (UFH) (n=8), Low-molecular-weight Heparin (LMWH) (n=13) or both (n=6) were initially used, followed by warfarin. In addition, a patient received an argatroban perfusion due to heparin-induced thrombocytopenia. Support treatment included oxygenotherapy (n=12), aminergic support (n=3) and venoarterial extracorporeal membrane oxygenation (ECMO) in a patient with refractory hemodynamic instability and hypoxia.
During follow up, three patients started non–vitamin K antagonist oral anticoagulants (NOAC) (n=2 apixaban, n=1 rivaroxaban), after a variable period of warfarin. Eight patients were anticoagulated for a defined period (average nine months).
The average length of hospitalization was 22.5 days (range 2-75). Eight patients (8/28, 28.6%) were admitted in the PICU (average 12.1 days). PE-mortality rate was 6.9% (2/29). A further dead occurred during hospitalization in a patient with acute lymphocytic leukemia, due to multisystemic dysfunction with multiple infarcts. During follow up (1 month to 12 years), two patients died from unascertained cause, 3.5 and 6 years after PE event (all-cause mortality 5/29,17.2%). Eighteen patients (64.3%) were submitted to a control CTPA, in average 8.4 months after PE, one presenting a PE recurrence (new territory, symptomatic). There were five recurrences of thrombotic events including two PE recurrences and an ischemic cerebrovascular accident. Furthermore, two patients had PST associated to May-Thurner syndrome and were proposed for vascular surgery. No anticoagulation hemorrhagic complications were registered.