The prevalence of angiodysplasia in
healthy individuals (mean age 61 years) in whom screening colonoscopies were
performed (0.93%).7 Most patients with angiodysplasia do not
experience GI bleeding; whereas <10% actively bleed. The increased propensity of patients with VWD to have formation of angiodysplasias is well established.3 The underlying mechanism of this clinical conditions appears associated with the role of high-molecular-weight multimers of plasma VWF as an antiangiogenic factor. Endothelial VWF has recently been identified as a negative modulator of VEGF-dependent angiogenesis and angiogenesis has shown to be increased in VWF deficiency.8-9 The diagnosis and treatment of recurring GI bleeding in VWD is challenging and associated with significant morbidity: patients frequently experience intractable bleeding episodes resulting in recurrent hospital admissions and exposure to multiple therapies of limited efficacy. Bleeding episodes can also develop and increase in severity with age.10 Due to diagnostic difficulty, in many patients the angiodysplastic lesions cannot be identified and the patients are described as having occult GI bleeding. The diagnosis is challenging due to accessibility, especially when the lesions are in the small bowel, and the requirement that active bleeding be present at the time of the examination for optimal identification.4 Whilst treatment of acute bleeding is fairly standard, a major issue is the recurrent nature of the bleeding and its prevention. Multiple physical and pharmacological therapies have been reported but none proven to be fully effective in every case.11 About pharmacological treatment, von Willebrand factor concentrate demonstrated to be effective for acute bleeding in 94.9% and was also effective in preventing bleeding in 84.6% of patients when given prophylactically.12 In a previous report from the VWN PN on the effectiveness of prophylaxis in VWD, Abshire and colleagues13 reported a reduction of annualized bleed rate from 8.4 to 6; the dose required for effective GI bleeding prevention remains unknown and although the VWD PN was designed to identify this, the number of patients enrolled with GI bleeding is so low that the answer is unlikely to come from this network. Other pharmacological approaches proposed for the prevention of recurrent GI bleeding from angiodysplasia include oestrogens, octreotide, thalidomide, atorvastatin and tamoxifen but no definitive data have been published until now. We reported a case of a misdiagnosis of VWD in a patients with melena and acute reduction of hemoglobin levels. The classical approach with basic routine coagulation evaluation and gastroscopy and colonoscopy didn't add useful information; moreover, second-level imaging tests aimed at finding the source of possible bleeding obviously yielded negative results. The choice of an exploratory laparotomy (hesitated in an intestinal resection) seemed to be the only applicable strategy. Under a clinical point of view, it is always necessary to consider the risk of a VWD before decide for a surgical approach to a GI bleeding. Diagnostic problems can be minimized by: (i) using improved methodologies (e.g., enzyme linked immunosorbant assay ELISA) (ii) extending the test panel, (iii) repeat testing using a fresh sample for confirmation, (iv) avoiding testing of stressed, ill or pregnant patients, and (v) using data from a desmopressin (DDAVP) challenge test.14 In conclusion, in order to prevent or reduce the risks erroneous surgical approach, we consider the future perspective to be the routine screening a VWD in presence of GI bleeding and signs of intestinal angiodysplasia.
The prevalence of angiodysplasia in