|ECR 2018 / C-0890||
|Assessment of severity and prognosis in patients with pulmonary embolism attending to clot load score on MDCT pulmonary angiography|
Methods and materials
- Data Source
From 400 patients registered in our institution between November 2010 and June 2015 with suspiction of acute PE, 70 patients were included for this analysis attending to positive findings at MDCT, from which clinical and imaging data were retrospectively reviewed.
All patients were aged ≥16 years (adults) and underwent at least one MDCT pulmonary angiographic examination with a suggestive PE event. Subjects were initially identified by means of procedure codes, then radiology reports were retrieved and reviewed by a trained radiologist with 10 years of experience in chest CT to confirm PE diagnosis.
a) Clinical data included information attending on demographic characteristics, admission dates, pre-test clinical risk factors (PESI scale) (Fig.1), discharge dates, laboratory results, therapeutic procedures, outcomes or deaths during hospitalization, by using the institutional medical archive system (HOSMA©).
b) Radiological data included imaging findings attending on MDCT pulmonary angiography studies, such as clot location, presence of RV dilatation, morfology of IV septum, PA hypertension, contrast reflux to IVC, pleural effusion and pulmonary infarctation among others, and they were retrieved and reviewed from our picture archiving and communication system (PACS).
PA clot load score: The presence, number and location of pulmonary arterial clots were scored from MDCT pulmonary angiography images, basing on parameters of Qanadli Score system (Fig.2). For our work, however, we did not assess the residual perfusion distal to the embolus as Qanadli score does, so that no weighting factor was needed to apply to the scoring results in any case. Thus, our resulting score system remained basically as shown in Fig.3.
Patients were categorized into the following three groups, according to the results of our clot burden quantification score:
- GROUP 1 (Low clot burden): score 1 – 5 points (Fig. 4)
- GROUP 2 (Moderate clot burden): score 6 – 14 points (Fig. 5)
- GROUP 3 (High clot burden): score 5 – 20 points (Fig. 6)
c) Follow-up data were retrieved and reviewed by a trained clinical physician with more than 10 years of experience, according to time of response to anticoagulant therapy, onset of complications, deaths, recurrences or secuelae. As secuelae-related data, chronic pulmonary hypertension (PH), chronic PE and chronic right heart failure events were reviewed.
- Statistical Analysis:
Normal distribution of measures of the clot burden was tested by using Kolmogorov – Smirnov test. The correlation between clot burden score and patients´prognosis and the correlation between clot volumen and MDCT signs of right heart dysfunction were assessed with the Pearson coefficient for normally distributed data and with the Spearman rank coefficient for nonnormally distributed data.
Pairwise comparison among groups was conducted by using the Mann-Whitney U test and Student´s t-test for assessing the statistical significance and the construction of 95% confidence intervals (CI). Statistical significance was defined as P < 0.05. X² test / Yates X² test and Fisher's exact test were used for the analysis of contingency tables.
All analyses were conducted by using SPSS STATISTICS©, version 20.0.
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