Background Pulmonary embolism (PE) is a potentially life-threatening condition in which a clot can migrate from the deep veins, most commonly in the leg, to the lungs. Conventional treatment of PE used unfractionated heparin (UFH), low molecular weight heparin (LMWH), fondaparinux, and vitamin K antagonists (VKAs). Recently, two forms of direct oral anticoagulants (DOACs) have been developed: oral direct thrombin inhibitors (DTIs) and oral factor Xa inhibitors. DOACs have characteristics that may be favourable to conventional treatment, including oral administration, a predictable effect, no need for frequent monitoring or re-dosing, and few known drug interactions. This review reports the efficacy and safety of these drugs in the long-term treatment of PE (minimum duration of three months). This is an update of a Cochrane Review first published in 2015. Objectives To assess the efficacy and safety of oral DTIs and oral factor Xa inhibitors versus conventional anticoagulants for the long-term treatment of PE. Search methods The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases, the World Health Organization International Clinical Trials Registry Platform and the ClinicalTrials.gov trials registers to 2 March 2022. We checked the reference lists of relevant articles for additional studies. Selection criteria We included randomised controlled trials (RCTs) in which people with a PE confirmed by standard imaging techniques were allocated to receive an oral DTI or an oral factor Xa inhibitor compared with a conventional anticoagulant or compared with each other for the long-term treatment of PE (minimum duration three months). Data collection and analysis We used standard Cochrane methods. Our primary outcomes were recurrent PE, recurrent venous thromboembolism (VTE), and deep vein thrombosis (DVT). Secondary outcomes were all-cause mortality, major bleeding, and health-related quality of life. We used GRADE to assess the certainty of evidence for each outcome. Main results We identified five additional RCTs with 1484 participants for this update. Together with the previously included trials, we have included ten RCTs with a total of 13,073 participants. Two studies investigated an oral DTI (dabigatran) and eight studies investigated oral factor Xa inhibitors (three rivaroxaban, three apixaban, and two edoxaban). The studies were of good methodological quality overall. Meta-analysis showed no clear difference in the efficacy and safety of oral DTI compared with conventional anticoagulation in preventing recurrent PE (odds ratio (OR) 1.02, 95% confidence interval (CI) 0.50 to 2.04; 2 studies, 1602 participants; moderate-certainty evidence), recurrent VTE (OR 0.93, 95% CI 0.52 to 1.66; 2 studies, 1602 participants; moderate-certainty evidence), DVT (OR 0.79, 95% CI 0.29 to 2.13; 2 studies, 1602 participants; moderate-certainty evidence), and major bleeding (OR 0.50, 95% CI 0.15 to 1.68; 2 studies, 1527 participants; moderate-certainty evidence). We downgraded the certainty of evidence by one level for imprecision due to the low number of events. There was also no clear difference between the oral factor Xa inhibitors and conventional anticoagulation in the prevention of recurrent PE (OR 0.92, 95% CI 0.66 to 1.29; 3 studies, 8186 participants; moderate-certainty evidence), recurrent VTE (OR 0.83, 95% CI 0.66 to 1.03; 8 studies, 11,416 participants; moderate-certainty evidence), DVT (OR 0.77, 95% CI 0.48 to 1.25; 2 studies, 8151 participants; moderate-certainty evidence), all-cause mortality (OR 1.16, 95% CI 0.79 to 1.70; 1 study, 4817 participants; moderate-certainty evidence) and major bleeding (OR 0.71, 95% CI 0.36 to 1.41; 8 studies, 11,447 participants; low-certainty evidence); the heterogeneity for major bleeding was significant (I-2 = 79%). We downgraded the certainty of the evidence to moderate and low because of imprecision due to the low number of events and inconsistency due to clinical heterogeneity. None of the included studies measured health-related quality of life. Authors' conclusions Available evidence shows there is probably little or no difference between DOACs and conventional anticoagulation in the prevention of recurrent PE, recurrent VTE, DVT, all-cause mortality, and major bleeding. The certainty of evidence was moderate or low. Future large clinical trials are required to identify if individual drugs differ in effectiveness and bleeding risk, and to explore effect differences in subgroups, including people with cancer and obesity.

BACKGROUND: With ongoing technical developments, MRI has notably evolved for the assessment of pulmonary vasculature. However, uncertainty persists about the performance of MRI for the diagnosis of acute pulmonary embolism (APE). OBJECTIVES: To clarify the comprehensive role of MRI for diagnosing APE. METHODS: Studies were identified through a search of Pubmed and Ovid databases. And QUADAS-2 tool was applied for quality assessment of the included studies. RESULTS: 15 studies on patient basis and 9 on vessel basis were retrieved. The patient-based analysis yielded an overall sensitivity of 0.75 (95% confidence interval 0.70-0.79) and 0.84 (0.80-0.87) for all patients and technically adequate patients, respectively; with an overall specificity of 0.80 (0.77-0.83) and 0.97 (0.96-0.98), and a pooled diagnostic odds ratio (DOR) of 51.07 (18.36-142.05) and 155.22 (86.83-277.47). A direct comparison of different MRI modalities showed that combined MRI test had the highest pooled DOR and the lowest proportion of inconclusive images. Of note, heterogeneity and moderate quality were observed. On vessel basis, MRI had high sensitivity and specificity in larger-order vessels, but a significantly lower sensitivity of 0.55 (0.50-0.60) for subsegmental APE. CONCLUSIONS: On patient-based level, MRI yields high diagnostic accuracies for the detection of APE, especially in technically adequate images. And the inconclusive MRI examinations virtually result from motion artifact and poor arterial opacification. Combined MRI test appears to be a more promising diagnostic tool with greater discrimination power over single techniques. From a vessel-based perspective, MRI exhibits high diagnostic capability with proximal arteries, while lacks sensitivity for peripheral embolism. This article is protected by copyright. All rights reserved