Background Oral factor Xa inhibitors (FXaI) can be administered in fixed doses without the need for routine laboratory monitoring. Anti-Xa assays can estimate anticoagulant effect for specific FXaI's. The aim of this study was to characterize anti-Xa levels in patients taking apixaban or rivaroxaban with major bleeding events. Methods Apixaban and rivaroxaban anti-Xa assays ordered within our hospital system from May 2016 to September 2019 were evaluated. The primary outcome was major bleeding events defined by International Society of Thrombosis and Haemostasis criteria. Median anti-Xa levels for each FXaI were calculated for those with and without major bleeding, as well as those who did and did not receive reversal agents. Results A total of 606 anti-Xa levels were analyzed. There were 146 major bleeding events documented, with the most common site being intracranial (63%). Median anti-Xa levels in patients with and without major bleeding were similar, whereas those on apixaban therapy who received reversal agents typically had higher anti-Xa levels (73 ng/mL vs. 153 ng/mL, p = 0.0019). Factors significantly associated with increased odds of bleeding were an age > 80 years, inappropriately high dosing regimens, and modest anti-Xa levels (100–300 ng/mL) for rivaroxaban specifically. Conclusions Older age and inappropriately high dosing regimens were associated with major bleeding in patients taking apixaban and rivaroxaban. Further investigation into the utility of anti-Xa levels for FXaI is warranted.

Background and Purpose— Digital subtraction angiography has been used as the gold standard to confirm successful aneurysmal obliteration after aneurysm clipping procedures using titanium or cobalt alloy clips. Computed tomographic angiography is a newer, less invasive imaging technique also used to confirm successful aneurysmal obliteration; however, its use compared with digital subtraction angiography remains controversial. Methods— A comprehensive literature search was conducted on Pubmed, EMBASE, and Cochrane databases through November 6, 2017, for studies that evaluated postclipping aneurysm obliteration with both computed tomographic angiography and digital subtraction angiography. Pooled sensitivity, specificity, positive likelihood ratio (LR+), and negative likelihood ratio (LR−) were calculated using the bivariate random-effects model. Results— Out of 6916 studies, 13 studies met inclusion criteria for this meta-analysis. A total of 510 patients with 613 aneurysms were included. Compared with digital subtraction angiography, which detected 87 residual aneurysms, computed tomographic angiography detected 58 resulting in a pooled sensitivity of 69% (95% CI, 54%–81%) and a pooled specificity of 99% (95% CI, 97%–99%). This corresponded to LR+ of 55.5 (95% CI, 23.6–130.9) and LR− of 0.31 (95% CI, 0.20–0.48). Univariate meta-regression revealed that the pooled sensitivity was worse in prospective designs ( P interaction <0.05), and the pooled specificity was better in higher-quality studies and for postoperative aneurysm diameters of <2 mm ( P interaction <0.001 for both). Conclusions— This meta-analysis revealed that computed tomographic angiography had a favorable LR+ but not a favorable LR−. Thus, this imaging modality may be applicable to rule in, but not rule out, residual aneurysms after clipping.

Introduction: Despite its widespread use, there is a paucity of data to guide the optimal use of arginine vasopressin (AVP) in critically ill patients with septic shock. Methods: This multicenter retrospective cohort study conducted in critically ill adults sought to evaluate the role of catecholamine requirements and timing on responsiveness to AVP. Responsiveness was defined as both a decrease in ≥ 50% of catecholamine requirements and no decrease in mean arterial pressure (MAP) at 4 hours post-AVP initiation. Primary outcomes of interest included the proportion of patients who started AVP within 4 hours after starting catecholamine therapy, as well as baseline norepinephrine (NE) equivalents (< 15, 15-39, or ≥ 40 mcg/min). Multivariate analyses and logistic regression were performed to identify other factors associated with AVP responsiveness. Results: There were 300 patients included in this study, with 74 patients being responders and 226 being non-responders. There was no significant difference in the number of patients who received AVP within 4 hours from catecholamine initiation between responders and non-responders (35% vs. 42%, P = 0.29). There were more patients in the non-responder group requiring ≥ 40 mcg/min of NE equivalents at AVP initiation (30% vs. 16%, P = 0.023). Stress dose steroid use was less common in responders (35% vs. 52%, P = 0.011), which was consistent with logistic regression analysis (OR 0.56, 95% 0.32-0.98, P = 0.044). Clinical outcomes between responders and non-responders were similar, apart from ICU (5.4% vs. 19.5%) and hospital (5.4% vs. 20.4%) mortality being lower in responders (P = 0.0032 and P = 0.0002, respectively). Conclusion: Shorter times to AVP initiation was not associated with responsiveness at 4 hours post-catecholamine initiation, although non-responders tended to require higher doses of NE equivalents at time of AVP initiation. Concomitant corticosteroids were associated with a lower likelihood of AVP responsiveness.