Introduction and objectives Current British Thoracic Society Guidelines state that a non-urgent pleural aspiration should be delayed in anti-coagulated patients until the international normalised ratio (INR) is <1.5.1 There is no specific guidance around the use of antiplatelet/other medications, which may further increase bleeding risk. This creates dilemma for clinicians regarding the best timing of performing pleural procedures to reduce bleeding risk. This study reviewed the potential impact of abnormal clotting results and/or anti-thrombotic medications on the occurrence of blood-stained pleural fluid at aspiration.
Methods This was a retrospective study, in a large teaching hospital, of all pleural procedures performed between 2013–15, where potential bleeding risk data was available. Diagnostic and therapeutic aspirations as well as intercostal chest drain insertions performed by the Respiratory team were included. An anti-thrombotic medication score for prescribed medications was recorded as follows: aspirin/prophylactic low molecular weight heparin (LMWH) = 1, clopidogrel/ticagrelor = 2, warfarin/therapeutic LMWH = 3, in addition to pre-procedure INR, APTT and platelet count. Pleural effusions were divided into ‘blood-stained’ and ‘non blood-stained’ and the medication score, INR, APTT and platelet count compared between the two groups.
Results 207 cases were analysed: 73% exudates, 27% transudates. Pleural fluid cytology was available in 77% cases, of which 25% were malignant. The results for the total sample size (n = 207) is shown in the attached table. For blood stained effusions, 33% were malignant vs. non blood stained, 17% malignant. Sub group analysis of malignant and benign effusions showed the same trend for blood stained vs. non blood stained effusions.
Conclusion Deranged coagulation or prescribed antithrombotics pre-pleural procedure do not appear to significantly increase the likelihood of a obtaining a blood-stained pleural effusion. The aetiology of blood stained pleural effusions is more likely multifactorial and should not always be attributed to a coagulation results or medication related increased bleeding risk. Further study could help determine how to better assess bleeding risk prior to pleural procedures.
Pleural procedures and thoracic ultrasound: BTS guideline 2010.