Anticoagulants and pulmonary embolism: the surprising impact of apixaban on bilateral embolism
R Brandao, A R Tomas, M Roxo Rosa Iglesias, C Silva, D MadeiraAbstract
Introduction
Pulmonary embolism (PE) is a serious condition that often requires anticoagulation therapy for prevention and treatment. However, some patients develop PE despite being on anticoagulant therapy, a situation that remains poorly studied and, therefore, understood.
Objectives
The aim of this study is to determine if anticoagulant (ACO) subtype is associated with increased severity or different clinical features of PE
Methods
We conducted a retrospective single-center cohort study of patients hospitalized with a diagnosis of PE between January 2018 and December 2023. Inclusion criteria were patients over 18 years old and those who had been receiving anticoagulation therapy prior to the onset of PE. The primary endpoint was to evaluate if the ACO subtype, i.e. direct oral anticoagulants (DOACs), vitamin K antagonists or low molecular weight heparin (LMWH), was associated with increased severity or different clinical features of PE. Severity was assessed by PE Severity Index Score (sPESI).
Results
From a total of 1197 patients, 59 (5.5%) were under therapeutic ACO by the time of PE diagnosis. Among the latter, 53% were female and the mean age was 76 years (±13 years), with no significant association between ACO subtype and patient sex (p = 0.072 and 0.52, respectively).78% were under a DOAC, specifically 34% with rivaroxaban, 25% with apixaban, 15% with edoxaban and 3% with dabigatran, whilst 13,5% were under LMWH. We found a statistically significant p=0.022) association between ACO and PE laterality, with patients on apixaban having a lower incidence of bilateral PE compared to those on other ACO. However, no significant difference was observed in the severity of PE between the different ACO groups (p= 0.983) as well as in terms of hospitalization time (mean Apixaban 23 days, mean Edoxaban: 18 days, mean Rivaroxaban:14 days vs mean LMWH: 27 days; p= 0.28). Our data have also highlighted a significant association (p=0,0056) between ACO and mortality, with patients in the LMHW group having a higher mortality rate than the DOAC groups.
Conclusion
According to our data, certain anticoagulants may be associated with different clinical findings in patients who develop PE despite therapy. Apixaban was associated with significantly less bilateral PE. LMWH group had significantly higher mortality rates when compared with the DOAC group, possibly due to higher baseline clinical instability. These results may highlight the need for further investigation into the role of anticoagulant choice in management and prevention of PE.