Abdulrehman, Jameel

Abstract Optimal management of anticoagulation for patients with aortic mechanical heart valves (MHVs) receiving vitamin K antagonists (VKAs) undergoing gastrointestinal endoscopic procedures is clinically challenging. Risk of bleeding from an unanticipated polypectomy or biopsy further complicates this issue. Current guidelines on use of bridging with low-molecular-weight heparin (LMWH) for these procedures are based on low-quality evidence. We conducted a subanalysis of a retrospective, multicenter observational study of adult patients with aortic MHVs receiving VKAs who underwent elective gastrointestinal endoscopies (colonoscopy or upper endoscopy). We included patients who underwent the procedure between July 1, 2020, and July 1, 2023, at five centers in Canada and the United States Patients with procedures performed on separate days within a 30-day period were excluded. Efficacy and safety outcomes included thromboembolic events, major bleeding (MB), and clinically relevant non-major bleeding (CRNMB) in the 30 days post procedure. A total of 192 endoscopic procedures were analyzed. Median (interquartile range [IQR]) patient age was 66 years (58.2–72.8) and 22% were female. Warfarin was interrupted for 185 procedures (96%). Among these, 119 (64%) received LMWH bridging: 33 (17%) pre-procedure only, 10 (5%) post-procedure only, and 76 (40%) both pre- and post-procedure. Post-procedure LMWH was initiated a median (IQR) of 1 day (1–1) and discontinued 5 days post-procedure (3–8). MB occurred in two patients (1%), CRNMB in two patients (1%), and one death (0.5%) was identified; no thromboembolic events occurred. Prior to propensity score matching (PSM), post-procedure LMWH with or without pre procedure LMWH was associated with the composite outcome of MB and CRNMB (P = 0.034), although not with MB or CRNMB individually. After stepwise regression and PSM analyses, no significant differences in bleeding outcomes were observed between patients who received LMWH bridging and those who did not. Our findings indicate that although adverse thrombotic events were rare and use of post-procedure LMWH bridging was significantly associated with a small absolute increased risk of bleeding, it was not significant after PSM. Larger prospective studies are needed to better inform antithrombotic management guidelines for patients with aortic MHVs undergoing gastrointestinal endoscopy.

AbstractBackgroundLaboratory diagnosis of von Willebrand Disease (VWD) is complex. Reliance on laboratory testing can be problematic as different VWD screening panels, assays and methodologies can produce analytic variability in test results.ObjectivesTo compare the degree of imprecision among the VWD assays and within the platelet binding activity (PBA) assays, to determine the consensus among the VWD assays for correct classification of sample results, and to determine consensus among laboratories’ von Willebrand factor (VWF) multimer interpretations and final interpretations of the VWD panels.Patients/MethodsProficiency testing results from the North American Specialized Coagulation Laboratory Association (NASCOLA) submitted by laboratories from 2010 to 2019 for all normal, type (T) 1 VWD and T2 VWD samples were analysed.Results and ConclusionsImprecision was lowest for VWF antigen and highest for collagen binding activity (CBA) with median coefficient of variation (CV) of 12% (interquartile range (IQR) 7%) and 23% (IQR 21%) respectively. Within the VWF PBA assays, the gain‐of‐function mutant GP1b binding (VWF: GP1bM) methods had the least imprecision (CV 9%, IQR 10%). All assays, including the various PBA methods had excellent consensus. The majority of laboratories agreed that normal (median consensus‐82%, IQR 16%) and T1 VWD (median consensus‐100%, IQR 9%) samples had normal multimer distribution. Consensus among laboratories for final interpretations was excellent for normal samples (median 81%, IQR 8%), good for T1 VWD samples (median 59%, IQR 9%), and fair for T2 VWD samples (median 44%, IQR 21%). Consensus on final interpretation decreased as sample complexity increased.