Clots in unusual places: lots of stress, limited data, critical decisions

Abstract

Although much less common than deep vein thrombosis of the lower extremities or lungs, clots in unusual locations, including the splanchnic, cerebral, retinal, upper-extremity, and renal locations, present with significant morbidity and mortality. In the last 2 decades, treatment of clots in these unusual locations is primarily managed medically, with interventional and surgical approaches reserved for more severe or refractory cases. The hematologist is well positioned to provide consultation to organ-specific specialties (ie, neurosurgery, hepatology, ophthalmology), especially because acquired and congenital hypercoagulability plays a major role, and anticoagulation is often the primary treatment. Historically, treatment has been based on expert opinion, but systematic reviews and meta-analyses have recently been published. Various societies have produced guidelines for the treatment of clots in unusual locations; however, randomized clinical trial data remain scarce. In the last few years, increasing data have emerged concerning the efficacy of the direct oral anticoagulants in treating clots in unusual locations. Cases have recently been described highlighting atypical thrombosis associated with COVID-19 infection as well as with the ChAdOx1 nCoV-19 (AstraZeneca) vaccine and Johnson and Johnson's Janssen Ad26.COV2.S vaccine. This article reviews clots in unusual locations with an emphasis on the splanchnic (mesenteric, portal, splenic, hepatic) and cerebral circulation. Through a case-based approach, key questions are posed, and data are presented to help guide diagnosis and treatment.

Abdominal venous thromboses: detection of the JAK2 p.V617F mutation by next-generation ultradeep sequencing—A prevalence study of patients in Mecklenburg-West Pomerania (2017–2021)

“…In the literature, in 50%−75% of patients with abdominal venous thromboses, the etiology could be identified ( 8 , 11 , 22 ). In addition to thrombophilia, acquired local and systemic pathophysiological factors are responsible; among the latter, MPNs are of particular importance ( 3 , 22 ). MPNs associated with abdominal venous thromboses predominantly show the mutation JAK2 p.V617F ( 2 ).…”

“…Abdominal venous thromboses are rare events (1). In the literature, hepatic vein thromboses (also known as Budd-Chiari syndrome), portal vein thrombosis, splenic vein thrombosis, and mesenteric vein thromboses are grouped as splanchnic vein thromboses (SVT) (1)(2)(3)(4). Incidences range from 0.7 per million people per year for hepatic vein thromboses to 70 per million people for portal vein thromboses (5)(6)(7).…”

Hemostasis Testing in the Emergency Department: A Narrative Review

“…In emergency settings, primary thromboembolic events typically include lower limb thrombosis and pulmonary embolism (PE), with less common occurrences such as cerebral venous thrombosis (CVT), splanchnic venous thrombosis (SVT), and central retinal vein occlusion (CRVO) also being diagnosed. 31 Deep vein thrombosis (DVT) typically manifests with nonspecific clinical symptoms such as acute pain, swelling, erythema in the lower extremities. Complications may include postthrombotic syndrome, PE and, in severe cases, death.…”