Recurrent jejunal bleeding due to angiodysplasia in a Bernard–Soulier patient:

Tranexamic acid may be a useful pharmacotherapy for endoscopically resistant small bowel angiodysplasia

Small bowel angiodysplasia (SBAD) is reported to account for nearly 50% of cases of small bowel bleeding. When SBAD occurs frequently, it is difficult to treat all the angiodysplasias endoscopically, and gastrointestinal bleeding often recurs. Hormone therapy, somatostatin analogs, thalidomide and vascular endothelial growth factor (VEGF)-neutralizing antibodies have been reported to reduce gastrointestinal angiodysplasia (GIAD) bleeding. However, there is no strong evidence to recommend them. Also, there are no guidelines for their use. Hereditary hemorrhagic telangiectasia (HHT) is a hereditary disease caused by abnormalities in VEGF, resulting in multiple GIADs. A treatment guideline has been created for GIAD in HHT, and the use of tranexamic acid, an antifibrinolytic agent, is the first recommendation pharmacotherapy for GIAD with gastrointestinal bleeding that is difficult to treat endoscopically. It has been reported that fibrinolysis is accelerated in GIAD patients who are not HHT, similar to HHT patients. The use of tranexamic acid for gastric antral vascular ectasia in GIAD has been reported to be useful. However, there are very few reports of its use for SBAD. There are concerns with tranexamic acid use regarding the development of thrombosis/embolism, but there are few reports of such side effects. Future clinical trials including tranexamic acid for SBAD are desired.

Anemia-Induced Bleeding in Patients with Platelet Disorders

Anemia is not only a consequence of bleeding, but also a modifiable risk factor for bleeding in patients with thrombocytopenia or platelet function defects. In this review we outline the mechanism of anemia-induced bleeding in patients with platelet disorders, which involves a disturbance in normal red blood cell (RBC) rheology and reduced platelet margination to the endothelial surface due to a decrease in RBC mass, leading to impaired primary hemostasis and bleeding. Biologically, anemia reduces the mass of RBCs in the central column of flowing blood through a vessel resulting in fewer platelets coming into contact with the endothelial surface at the periphery of the flowing blood column. Thus, anemia results in impaired primary hemostasis. Von Willebrand factor (vWF) is another component of primary hemostasis and vWF deficiency, especially a deficiency of the highest vWF multimers, can also manifest with bleeding when concomitant anemia occurs. Clinically, patients at greatest risk for anemia-induced bleeding include patients with hematological malignancies in whom anemia and thrombocytopenia occur as a result of the underlying disease or the myelotoxic effects of treatment; patients with renal insufficiency with uremic thrombocytopathy and hypoproliferative anemia; and patients with inherited or acquired bleeding disorders affecting primary hemostasis (eg, Bernard-Soulier syndrome, von Willebrand disease) with chronic blood loss and iron deficiency anemia. Underlying abnormalities of any components of primary hemostasis plus concomitant anemia may result in major bleeding disorders; therefore, correction of remediable abnormalities-most notably, correction of the anemia- would be expected to have important clinical benefit. In this review we discuss how the correction of the anemia may lead to improvement of bleeding outcomes in patients with a primary hemostatic defect, supported by evidence from animal models, clinical trials and clinical experience.

Small bowel bleeding: cause and the role of endoscopy and medical therapy

PURPOSE OF REVIEW

The objective is to provide an overview on the cause of small bowel bleeding. We discuss the role of small bowel endoscopy in the management of small bowel bleeding and provide an outline of pharmacotherapy that can be additionally beneficial.

RECENT FINDINGS

Small bowel capsule endoscopy (SBCE) is the initial diagnostic investigation of choice in small bowel bleeding. Computed tomography (CT) can be helpful in the context of small bowel tumours. Device-assisted enteroscopy (DAE) enables several therapeutic procedures such as argon plasma coagulation (APC) and haemoclip application. It can also guide further management with histology or by marking culprit lesions with India ink. A persistent rate of rebleeding despite APC is increasingly being reported. Pharmacotherapy has an emerging role in the management of small bowel bleeding. Somatostatin analogues are a well tolerated class of drugs that can play an additional role in the management of refractory bleeding secondary to small bowel angioectasias.

SUMMARY

SBCE is useful in determining the cause of small bowel bleeding. DAE offers an endoscopic therapeutic approach to small bowel bleeding replacing surgery and intraoperative enteroscopy. Pharmacotherapy, in addition to endotherapy, can play an important role in the management of multifocal, recurring bleeding small bowel lesions.

Overview of small bowel angioectasias: clinical presentation and treatment options

Elderly patients with multiple co-morbidities are at an increased risk of developing small bowel angioectasias. Treating these lesions can be both challenging and costly with patients requiring extensive investigations and recurrent admissions for iron infusions and blood transfusions as well as invasive procedures. This review presents treatment options and describes in detail drugs that should be considered whilst taking into account their effectiveness and their safety profile. Areas covered: A PubMed search was carried out using the following keywords: small bowel angiodysplasias, small bowel angioectasias, small bowel bleeding and obscure gastrointestinal bleeding to assess existing evidence. The pathophysiology and risk factors are covered in this review together with appropriate methods of investigation and management. Treatment options discussed are endoscopic measures, surgical options and pharmacotherapy. The role of serum biomarkers is also discussed. Expert commentary: Future work should be directed at alternative drugs with a good safety profile that target biomarkers. Novel pharmacotherapy directed at biomarkers could potentially provide a non-invasive treatment option for angioectasias particularly in the elderly where management can be challenging.

Von Willebrand factor and angiogenesis: basic and applied issues

The recent discovery that von Willebrand factor (VWF) regulates blood vessel formation has opened a novel perspective on the function of this complex protein. VWF was discovered as a key component of hemostasis, capturing platelets at sites of endothelial damage and synthesized in megakaryocytes and endothelial cells (EC). In recent years, novel functions and binding partners have been identified for VWF. The finding that loss of VWF in EC results in enhanced, possibly dysfunctional, angiogenesis is consistent with the clinical observations that in some patients with von Willebrand disease (VWD), vascular malformations can cause severe gastrointestinal (GI) bleeding. In vitro and in vivo studies indicate that VWF can regulate angiogenesis through multiple pathways, both intracellular and extracellular, although their relative importance is still unclear. Investigation of these pathways has been greatly facilitated by the ability to isolate EC from progenitors circulating in the peripheral blood of normal controls and patients with VWD. In the next few years, these will yield further evidence on the molecular pathways controlled by VWF and shed light on this novel and fascinating area of vascular biology. In this article, we will review the evidence supporting a role for VWF in blood vessel formation, the link between VWF dysfunction and vascular malformations causing GI bleeding and how they may be causally related. Finally, we will discuss how these findings point to novel therapeutic approaches to bleeding refractory to VWF replacement therapy in VWD.