Recurrent Thrombi in an Obese Patient With History of Bariatric Surgery Despite Anti-Xa Therapy.

Obesity and gastric bypass surgery can complicate anticoagulation therapy. In general, patients post-bariatric surgery are considered to be at a moderate risk for deep venous thromboembolism or pulmonary embolism. American Association of Clinical Endocrinologists/American College of Endocrinology, The Obesity Society, American Society for Metabolic & Bariatric Surgery, Obesity Medicine Association, and American Society of Anesthesiologists guidelines recommend chemical prophylaxis with unfractionated heparin or low molecular weight heparin after surgery until the patient is fully mobile, and for those who require chronic anticoagulation, the International Society of Thrombosis and Haemostasis recommend warfarin if body mass index (BMI) is above 40 kg/m2 or weight is more than 120 kg. Clinical decision making regarding anticoagulation in the following patient case is complicated by multiple factors, most notably the combination of obesity and history of gastric bypass surgery. This patient failed multiple anticoagulation regimens, with apixaban and rivaroxaban therapies each ending in venous thromboemboli and warfarin leading to subtherapeutic International Normalized Ratio (INR)s despite dose adjustment. However, she is currently therapeutic on the combination of enoxaparin and warfarin as shown by INR and anti-Xa level monitoring. In this case and similar instances, there could be a need for anticoagulant dose adjustments, different INR goals, or a combination of different anticoagulants. Providers should take an individualized approach to patients who have had bariatric surgery with elevated BMI as a key factor in anticoagulant selection.

Cangrelor Dosing and Monitoring for Prevention of Acute Systemic-to-Pulmonary Artery Shunt Thrombosis in Neonates.

OBJECTIVE: Systemic-to-pulmonary artery shunts are amongst the most common palliative procedures performed in neonates with congenital heart defects. These procedures require immediate postoperative thromboprophylaxis to prevent life-threatening shunt thrombosis. The novel use of intravenous P2Y12 platelet receptor antagonists has led to a need for dosing recommendations and monitoring. This study aims to determine cangrelor dosing in neonates through laboratory assessment of P2Y12 receptor reactivity and adverse events. METHODS: Observational retrospective cohort study on the use of cangrelor for thromboprophylaxis in the immediate postoperative period of neonates undergoing placement of systemic-to-pulmonary artery shunts in a tertiary children's hospital from March 2020 to March 2021. RESULTS: Ten neonates receiving cangrelor post systemic-to-pulmonary artery shunt placement were included in the study. Median age and weight were 4 days (IQR, 2.75-5.25) and 3.49 kg (IQR, 3.1-3.75), respectively. Five (50%) patients received a 3.5-mm shunt, while the remaining patients received a 4-mm shunt. For thrombin inhibition, 5 (50%) patients received heparin and 5 (50%) received bivalirudin. Median cangrelor dose was 0.1 mcg/kg/min (IQR, 0.1-0.1). Median achieved P2Y12 reaction units (PRU) at this cangrelor dose was 127.5 (IQR, 72.5-173.75). No shunt thrombosis occurred in these patients; however, there was 1 minor hemorrhagic event. CONCLUSIONS: Our study suggests that a cangrelor dose of 0.1 mcg/kg/min is associated with therapeutic PRU and prevents shunt thrombosis in neonates post systemic-to-pulmonary artery shunt, with minimal hemorrhagic complications.