Observed Apixaban Anti-Xa Levels in Obese Patients.

BACKGROUND: Recent guidelines suggest that, for venous thromboembolism (VTE), standard doses of apixaban are appropriate in patients with body mass index (BMI) >40 kg/m2 or >120 kg. Atrial fibrillation (AF) is excluded from this recommendation. OBJECTIVE: The goals of our study were to measure and describe anti-Xa levels of patients with a BMI ≥40 kg/m2 and/or a weight ≥120 kg with a clinical indication of AF or VTE who were treated with apixaban, and to determine whether BMI or weight are associated with anti-Xa levels in this population. METHODS: We conducted an observational cohort study at a single health care system in Oregon, USA. Patients meeting enrollment criteria were recruited and had peak and trough apixaban anti-Xa levels drawn. RESULTS: Of 55 patients enrolled, 5 (9%) had peak anti-Xa levels below the reference range and 3 (6%) had trough anti-Xa levels below the reference range. BMI did not significantly correlate with peak or trough anti-Xa levels (r = -0.10, p = 0.45 and r = -0.14, p = 0.31). Weight had a moderate, negative correlation with peak anti-Xa levels (r = -0.42, p = 0.002) and a weak, negative correlation with trough anti-Xa levels (r = -0.32, p = 0.02). CONCLUSIONS AND RELEVANCE: This study provides evidence that anti-Xa levels among obese patients are not substantially different from patients with nomral BMI and weight. This supports recent ISTH guidance for standard dosing of apixaban for VTE patients with BMI >40 kg/m2 or weight >120 kg and provides additional evidence that the standard dosing may also be appropriate in patients with AF.

Successful long-term stenting of an atypical descending aortic coarctation.

Stenotic lesions of the descending aorta are rare causes of coarctation of the aorta. The majority of cases of atypical coarctation are thought to be caused by Takayasu's arteritis. This report describes an atypical coarctation of the descending aorta treated with angioplasty and stent placement. Patency of the stent and control of the hypertension at 2 and a half years suggest that endovascular treatment of atypical coarctation may be successful with the use of mechanical stents and may be an alternative to surgical correction.