Gastrointestinal bleeding, angiodysplasia, cardiovascular disease, and acquired von Willebrand syndrome

Characterization of Von Willebrand Factor Multimer Structure in Patients With Severe Aortic Stenosis

Acquired von Willebrand syndrome (AVWS) associated with severe aortic stenosis (AS) has been frequently subclassified into a subtype 2A based on the deficiency of high-molecular-weight (HMW) multimers as it is seen in inherited von Willebrand disease (VWD) type 2A. However, the multimeric phenotype of VWD type 2A does not only include an HMW deficiency but also a decrease in intermediate-molecular-weight (IMW) multimers and an abnormal inner triplet band pattern. These additional characteristics have not been evaluated in AVWS associated with severe AS. Therefore, we recruited N = 31 consecutive patients with severe AS and performed a high-resolution Western blot with densitometrical band quantification to characterize the von Willebrand factor (VWF) multimeric structure and reevaluate the AVWS subtype classification. Study patients showed an isolated HMW VWF multimer deficiency without additional abnormalities of the IMW portions and the inner triplet structure in 65%. In conclusion, the multimeric pattern of AVWS associated with severe AS does neither resemble that seen in AVWS type 2A nor that seen in inherited VWD type 2A. Therefore, a subclassification into a type 2A should not be used.

Gastrointestinal angiodysplasia and bleeding in von Willebrand disease

Von Willebrand disease (VWD), the most common genetic bleeding disorder, is characterised by a quantitative or qualitative defect of von Willebrand factor (VWF). Patients with VWD suffer from mucocutaneous bleeding, of severity usually proportional to the degree of VWF defect. In particular, gastrointestinal bleeding associated with angiodysplasia is often a severe symptom of difficult management. This review focuses on the pathophysiology, diagnosis and treatment of VWD-associated gastrointestinal angiodysplasia and related bleeding.

Ileal angiodysplasia presentation as a bowel obstruction: A case report

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Angiodysplasia is an important cause of both overt and occult gastrointestinal bleeding.

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However, angiodysplasia should also be kept in mind while dealing with an acute abdomen due to a bowel obstruction, especially in elderly patients with occult gastrointestinal bleeding.

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Such exceptional presentation of angiodysplasia can be explained by the development, in the digestive submucosa, of acquired arteriovenous malformation with multiple shunts and rapid blood flow. This results in an inadequate oxygenation of a segment of intestine, chronic ischemia, wall thickness and stenosis and bowel obstruction.

Introduction

Angiodysplasia is a common vascular abnormality of the gastrointestinal tract, found in the elderly and most frequently revealed by gastrointestinal bleeding. We report an original case of ileal angiodysplasia in an 83-year-old woman presenting as a bowel obstruction.

Case presentation

An 83-year-old woman with a medical history of chronic untreated anemia, presented with cardinal symptoms of bowel obstruction. Computed tomography revealed diffuse ileal wall thickening with multiple zones of stenosis, which were aggravated by an ileal perforation and associated with vascular abnormalities compatible with angiodysplasia. Surgery confirmed the imaging findings. A large resection importing one meter of ileum was performed. The pathology report of the resected specimen revealed ischemic lesions of ileum associated with ileal angiodysplasia. The postoperative period was marked by an acute dehydration in the patient who died 3 weeks after surgery.

Discussion

Angiodysplastic lesions develop with aging due to chronic low-grade intermittent obstruction of submucosal veins. These lesions are the result of increased contractility at the level of muscularis propria, leading to congestion of the capillaries and failure of pre-capillary sphincters, resulting in the formation of small arteriovenous collaterals. The acquired arteriovenous malformation consisting of multiple shunts with rapid blood flow may result in inadequate oxygenation of a segment of the intestine and lead to ischemia and eventually wall thickening, stenosis and even perforation of the small bowel.

Conclusion

Angiodysplasia should be kept in the back of one’s mind as one of the causes of acute abdomen and bowel obstruction, especially in elderly people suffering from occult gastrointestinal bleeding.

Angiodysplasia in von Willebrand Disease: Understanding the Clinical and Basic Science

Severe and intractable gastrointestinal bleeding caused by angiodysplasia is a debilitating problem for up to 20% of patients with von Willebrand disease (VWD). Currently, the lack of an optimal treatment for this recurrent problem presents an ongoing challenge for many physicians in their management of affected patients. Over the past few years, studies have pointed to a regulatory role for the hemostatic protein, von Willebrand factor (VWF), in angiogenesis, providing a novel target for the modulation of vessel development. This article will review the clinical implications and molecular pathology of angiodysplasia in VWD.

Debate: creating adequate pulse with a continuous flow ventricular assist device: can it be done and should it be done? Probably not, it may cause more problems than benefits!

PURPOSE OF REVIEW

The feasibility and benefits of creating adequate pulsatility with continuous flow left ventricular assist devices (LVADs) have long been debated. This review discusses recent technical and clinical findings to answer whether such intervention should be implemented in the standard patient management.

RECENT FINDINGS

Only a limited amount of pulsatility can be generated by periodic speed steps, both considerably smaller in flow increase and in pace rate than the natural circulation. Organ systems are not impeded in their normal function and even not in recovery by a continuous flow. Known problems such as gastrointestinal bleeding are not necessarily due to pulsatility per se, or not important for therapeutic progress, such as minor modifications of the arterial walls.

SUMMARY

The speculative benefits of augmented pulsatility with continuous flow LVADs could be overrated and are still incompletely evaluated. Potential risks that might arise from this strategy should be carefully weighed before implementing extensive pulsatility as standard patient management.

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.

Monitoring hemostasis parameters in left ventricular assist device recipients - a preliminary report

Introduction

Mechanical circulatory support (MCS) therapy is associated with the improvement of long-term prognosis in patients with end-stage heart failure. For years it has been used as a bridge to transplant. However, more recently it is even being used as a destination therapy. Recently, clinicians have identified common MCS therapy-associated complications: pump thrombosis, bleeding, and hemolysis. These complications are very challenging with regard to both diagnosis and management.

Aim

To determine time-dependant changes of selected hemostasis/coagulation parameters in patients with end-stage heart failure treated with MCS and antithrombotic therapy.

Material and methods

Sixteen patients with end-stage heart failure on left ventricular assist device (LVAD) were followed for 6 weeks (six blood samples for each patient). Every week an extended hemostasis panel was assessed, including activated partial thromboplastin time, prothrombin time, international normalized ratio, von Willebrand factor (vWF) activity, factor VIII activity, fibrinogen level, D-dimer, platelet response to arachidonic acid (ASPI test) and adenosine diphosphate (ADP test), thrombin receptor activating peptide-6 (TRAP test) and collagen (COL test).

Results

The study population comprised 16 men. The median time from LVAD implantation was 120 days (100–150 days). During the study period the D-dimer and fibrinogen concentrations were elevated but remained similar throughout all six measurements. Meanwhile factor VIII and vWF activities were elevated in the first two measurements and then subsequently declined. Inhibition of platelet aggregation was greater early after LVAD implantation. During subsequent weeks the inhibition of platelet aggregation was less pronounced. No patient developed any bleeding or thrombo-embolic event during the study period.

Conclusions

Patients on MCS therapy demonstrate significant time-dependant changes in hemostasis parameters (both in the coagulation system and platelet aggregation).

Treatment of acquired von Willebrand syndrome in aortic stenosis with transcatheter aortic valve replacement

OBJECTIVES

This study sought to investigate the prevalence of abnormal von Willebrand multimers (AbM) in patients undergoing transcatheter aortic valve replacement (TAVR) and the impact of TAVR on the underlying factor variances.

BACKGROUND

An association between the acquired von Willebrand syndrome (aVWS) and valvular aortic stenosis (AS) has been established in the past and surgical aortic valve replacement (SAVR) shown to lead to factor recovery. Prevalence and course of AbM in patients treated with TAVR though has not yet been described comprehensively.

METHODS

Ninety-five consecutive patients underwent TAVR at our institution. Hemostaseologic testing was performed before and up to 1 week after TAVR. Transvalvular and right heart hemodynamics as well as bleeding episodes were recorded and analyzed with descriptive statistics.

RESULTS

Baseline prevalence of AbM was 42% with an average high-molecular-weight multimer (HMWM) count of 16.2 ± 3.3%. Pressure gradients correlated significantly with the extent of HMWM deficiency (r = -0.63 [p < 0.0001]). Following valve implantation, HMWM increased proportional to the drop in mean pressure gradient and normalized in most of the patients. However, residual aortic regurgitation/leakage led to inferior HMWM recovery but prosthesis-patient mismatch (PPM) was rare and left HMWM uninfluenced. We saw no association of transfusion with AbM and 1-year mortality was unaffected by AbM.

CONCLUSIONS

AbM in patients with AS undergoing TAVR is frequent. However, TAVR is capable of correcting AbM and therefore possibly aVWS in patients with AS. As opposed to SAVR, bleeding and transfusion requirement in TAVR patients was not associated with severe HMWM deficiency; PPM was rare and HMWM were uninfluenced by the procedure. Aortic regurgitation after TAVR adversely influenced HMWM recovery.

Increased bleeding risk in patients with aortic valvular stenosis: From new mechanisms to new therapies

Aortic stenosis (AS), the most prevalent acquired valvular disease in the adults that requires invasive treatment, coexists with coagulopathy, resulting in bleeding in approximately 20% of patients. In the current review, we summarize the available knowledge on the mechanisms underlying the bleeding tendency observed in AS, and discuss potential compensatory mechanisms preventing most patients with severe AS from experiencing bleeding. We offer an update on Heyde's syndrome and other types of bleeding, and study extensively their pathobiology, providing insights into the new emerging concepts on coagulation regulation in AS. The focus is given to the impact of valvular interventions on coagulation abnormalities in AS. Both surgical valve replacement and transcatheter aortic valve implantation are discussed. Finally, we discuss current treatment recommendations in AS related bleeding.

Circulatory support devices: fundamental aspects and clinical management of bleeding and thrombosis

Circulatory support devices are increasingly being used to overcome cardiac or respiratory failure. Long-term devices are used either as a 'bridge to transplant' to support patients who are unable to wait any longer for a heart transplant, or, more recently, as 'destination therapy' for older patients suffering from end-stage heart failure and who have contraindications to heart transplantation. Short-term support devices for high-risk percutaneous coronary intervention, or as a 'bridge for decision' for patients suffering from refractory cardiogenic shock, have also been developed. The clinical benefit of such assist devices has been demonstrated in several important studies, but, unfortunately, thrombotic and bleeding complications are two major clinical issues in patients requiring these devices. Overcoming these issues is of major importance to allow the safe and broad use of these devices, and to consider them as true alternatives to heart transplantation. The present review focuses on thrombotic and bleeding complications, and describes how the risk of thrombosis and bleeding may vary according to the clinical indication, but also according to the type of device. We describe the current knowledge of the mechanisms underlying the occurrence of these complications, provide some guidance for choosing the most appropriate anticoagulation regimen to prevent their occurrence for each type of device and indication, and provide some recommendations for the management of patients when the complication occurs.

Von Willebrand factor in patients on mechanical circulatory support - a double-edged sword between bleeding and thrombosis

Mechanical circulatory support (MCS) is an umbrella term describing the various technologies used in both short- and long-term management of patients with either end-stage chronic heart failure (HF) or acute HF. Most often, MCS has emerged as a bridge to transplantation, but more recently it is also used as a destination therapy. Mechanical circulatory support includes left ventricular assist device (LVAD) or bi-ventricular assist device (Bi-VAD). Currently, 2- to 3-year survival in carefully selected patients is much better than with medical therapy. However, MCS therapy is hampered by sometimes life-threatening complications including bleeding and device thrombosis. Von Willebrand factor (vWF) has two major functions in haemostasis. First, it plays a crucial role in platelet-subendothelium adhesion and platelet-platelet interactions (aggregation). Second, it is the carrier of factor VIII (FVIII) in plasma. Von Willebrand factor prolongs FVIII half-time by protecting it from proteolytic degradation. It delivers FVIII to the site of vascular injury thus enhancing haemostatic process. On one hand, high plasma levels of vWF have been associated with an increased risk of thrombosis. On the other, defects or deficiencies of vWF underlie the inherited von Willebrand disease or acquired von Willebrand syndrome. Here we review the pathophysiology of thrombosis and bleeding associated with vWF.

Characteristics of gastrointestinal bleeding after placement of continuous-flow left ventricular assist device: a case series

BACKGROUND

Medical management of patients with continuous-flow left ventricular assist devices (LVADs) remains challenging for the gastroenterologist given their high risk of gastrointestinal bleeding (GIB) and need for continuous anticoagulation.

AIMS

Our aim was to better characterize LVAD patients who presented with a GIB at our facility and delineate the prevalence, presentation, time to diagnosis, management, and therapeutic endoscopic interventions, including small bowel tools that may offer additional benefit.

METHODS

We retrospectively reviewed adult patients (>18 years) who underwent LVAD implantation at our tertiary care facility between October 2011 and October 2013. Electronic medical records were reviewed for presenting symptoms, average days to initial and repeat GIB, hospital course, and techniques that led to diagnosis and hemostasis.

RESULTS

Eighteen patients underwent LVAD implantation, of which 61 % presented with a GIB for a total of 20 presentations (1.8 per patient). Mean time to initial GIB was 154 days. Patients required an average of 1.8 endoscopic procedures per admission. Esophagogastroduodenoscopy (EGD) and push enteroscopy (PE) were more likely to lead to a diagnosis, and EGD was the most commonly used diagnostic tool at initial presentation. Sixty percent of patients who initially received EGD presented with a recurrent GIB and required PE, which was diagnostic and therapeutic for small bowel angiodysplasias in 80 % of cases.

CONCLUSION

We found a higher GIB rate compared with prior studies. Bleeding events were associated with multiple procedures and interventions. We recommend an algorithmic approach to LVAD patients who bleed. Our experience suggests that PE is warranted at initial presentation in order to achieve hemostasis, prevent recurrent GIB, and decrease subsequent readmission rates.

Blood coagulation and fibrinolysis in aortic valve stenosis: links with inflammation and calcification

Aortic valve stenosis (AS) increasingly afflicts our aging population. However, the pathobiology of the disease is still poorly understood and there is no effective pharmacotherapy for treating those at risk for clinical progression. The progression of AS involves complex inflammatory and fibroproliferative processes that resemble to some extent atherosclerosis. Accumulating evidence indicates that several coagulation proteins and its inhibitors, including tissue factor, tissue factor pathway inhibitor, prothrombin, factor XIII, von Willebrand factor, display increased expression within aortic stenotic valves, predominantly on macrophages and myofibroblasts around calcified areas. Systemic impaired fibrinolysis, along with increased plasma and valvular expression of plasminogen activator inhibitor-1, has also been observed in patients with AS in association with the severity of the disease. There is an extensive cross-talk between inflammation and coagulation in stenotic valve tissue which contributes to the calcification and mineralisation of the aortic valve leaflets. This review summarises the available data on blood coagulation and fibrinolysis in AS with the emphasis on their interactions with inflammation and calcification.

Current management of von Willebrand disease and von Willebrand syndrome

PURPOSE OF REVIEW

Anesthesiologists frequently care for patients with altered hemostasis and coagulation. Where a clear history of familial and personal bleeding exists, a thoughtful plan can be developed in advance to manage the issue perioperatively. However, in some cases, it may not be known that the patient has a disorder until excessive bleeding is noted during or after surgery. Recognition of the issue and appropriate targeted therapy are the keys to successful management.

RECENT FINDINGS

With an estimated prevalence approaching 1% of the population, von Willebrand disease (vWD) is the most common hereditary bleeding diathesis, but the estimated prevalence of acquired vWD (often termed von Willebrand syndrome or vWS) is now believed to be significantly higher, especially in patients with malignancies, autoimmune diseases, cardiac valvular lesions, and in patients on mechanical circulatory support devices. Acquired vWD may also occur with certain medications.

SUMMARY

The mainstay of the diagnosis of vWD is laboratory testing. Preoperative clinical assessment and a high level of suspicion are often effective to alert the anesthesiologist to the possibility of vWS, thus allowing for appropriate testing and potential prophylaxis in elective situations, as well as appropriately targeted therapy of unexpected bleeding when a hemostatic derangement was not anticipated preoperatively.

Recovery from anemia in patients with severe aortic stenosis undergoing transcatheter aortic valve implantation--prevalence, predictors and clinical outcome

Introduction

Preoperative anemia is common in patients with severe aortic stenosis undergoing transcatheter aortic valve implantation (TAVI) and has been linked to a poorer outcome – including a higher 1-year mortality. The aim of this study was to investigate the impact of successful TAVI on baseline anemia.

Methods

A total of 253 patients who survived at least 1 year following TAVI were included in this study. The prevalence, predictors and clinical outcome of hemoglobin (Hb)-recovery were assessed.

Results

The prevalence of baseline anemia was 49% (n = 124) – recovery from anemia occurred in 40% of the anemic patients (n = 49) at 1 year after TAVI with an increase in mean Hb-level of 1.35 g/dL from baseline. This increase was not related to an improvement in renal function. At multivariate analysis, a high peak gradient (OR 4.82, P = 0.003) was shown to be an independent predictor for Hb-recovery, while blood transfusion (OR 0.31, P = 0.038) and chronic kidney disease (CKD, OR 0.33, P = 0.043) were identified as negative predictors at, respectively, one and two years after TAVI. When compared to patients without baseline anemia, those anemic patients with Hb-recovery had a similar functional improvement (OR 0.98, P = 0.975), whereas those without Hb-recovery had a significantly lower likelihood of functional improvement with ≧2 NYHA classes (OR 0.49, P = 0.034) and a higher likelihood of re-hospitalization within the first year after TAVI (OR 1.91, P = 0.024).

Conclusion

Recovery from anemia occurs in 40% of anemic patients at 1 year after TAVI – mainly in those with a high gradient and without CKD. Blood transfusion was found to have a transient adverse effect on this Hb-recovery. Finally, anemic patients without Hb-recovery experience less functional improvement and have a higher re-hospitalization rate within the first year after TAVI.

Severe aortic stenosis: forgotten associations

The authors present the case of a 68-year-old man with predominantly right heart failure in the context of severe aortic stenosis associated with pulmonary hypertension. Anemia was diagnosed which, after endoscopic study, was considered to be secondary to angiodysplasia and a diagnosis of Heyde syndrome was made. After valve replacement surgery the patient's heart failure improved and hemoglobin levels stabilized. We present this case to show the need to recognize less common associations of severe aortic stenosis, in order to provide immediate and appropriate treatment.

Effect of transcutaneous aortic valve implantation on the Heyde's syndrome

The association between aortic valve stenosis and gastrointestinal bleeding, traditionally known as Heyde's syndrome, is the result of a quantitative loss of the highest molecular weight von Willebrand multimers (type 2A von Willebrand syndrome). This results in bleeding from areas of high shear stress such as gastrointestinal angiodysplasias. Correction of this bleeding diathesis after surgical aortic valve replacement has been well described. The effect of transcutaneous aortic valve implantation on Heyde's syndrome has yet to be studied. Herein, we report a patient with severe aortic stenosis, type 2A von Willebrand syndrome, and hemorrhagic shock from gastrointestinal bleeding who underwent successful transcutaneous aortic valve implantation.

Update on von Willebrand factor multimers: focus on high-molecular-weight multimers and their role in hemostasis

Normal hemostasis requires von Willebrand factor (VWF) to support platelet adhesion and aggregation at sites of vascular injury. VWF is a multimeric glycoprotein built from identical subunits that contain binding sites for both platelet glycoprotein receptors and collagen. The adhesive activity of VWF depends on the size of its multimers, which range from 500 to over 10 000 kDa. There is good evidence that the high-molecular-weight multimers (HMWM), which are 5000-10 000 kDa, are the most effective in supporting interaction with collagen and platelet receptors and in facilitating wound healing under conditions of shear stress. Thus, these HMWM of VWF are of particular clinical interest. The unusually large multimers of VWF are, under normal conditions, cleaved by the plasma metalloproteinase ADAMTS13 to smaller, less adhesive multimers. A reduction or lack of HMWM, owing to a multimerization defect of VWF or to an increased susceptibility of VWF for ADAMTS13, leads to a functionally impaired VWF and the particular type 2A of von Willebrand disease. This review considers the biology and function of VWF multimers with a particular focus on the characterization of HMWM - their production, storage, release, degradation, and role in normal physiology. Evidence from basic research and the study of clinical diseases and their management highlight a pivotal role for the HMWM of VWF in hemostasis.

Review article: gastrointestinal angiodysplasia - pathogenesis, diagnosis and management

BACKGROUND

Angiodysplasia (AD) of the gastrointestinal (GI) tract is an important condition that can cause significant morbidity and -rarely - mortality.

AIM

To provide an up-to-date comprehensive summary of the literature evaluating this disease entity with a particular focus on pathogenesis as well as current and emerging diagnostic and therapeutic modalities. Recommendations for treatment will be made on the basis of the current available evidence and consensus opinion of the authors.

METHODS

A systematic literature search was performed. The search strategy used the keywords 'angiodysplasia' or 'arteriovenous malformation' or 'angioectasia' or 'vascular ectasia' or 'vascular lesions' or 'vascular abnormalities' or 'vascular malformations' in the title or abstract.

RESULTS

Most AD lesions (54-81.9%) are detected in the caecum and ascending colon. They may develop secondary to chronic low-grade intermittent obstruction of submucosal veins coupled with increased vascular endothelial growth factor-dependent proliferation. Endotherapy with argon plasma coagulation resolves bleeding in 85% of patients with colonic AD. In patients who fail (or are not suitable for) other interventions, treatment with thalidomide or octreotide can lead to a clinically meaningful response in 71.4% and 77% of patients respectively.

CONCLUSIONS

Angiodysplasia is a rare, but important, cause of both overt and occult GI bleeding especially in the older patients. Advances in endoscopic imaging and therapeutic techniques have led to improved outcomes in these patients. The choice of treatment should be decided on a patient-by-patient basis. Further research is required to better understand the pathogenesis and identify potential therapeutic targets.

Von Willebrand factor, angiodysplasia and angiogenesis

The large multimeric glycoprotein Von Willebrand factor (VWF) is best known for its role in haemostasis; however in recent years other functions of VWF have been identified, indicating that this protein is involved in multiple vascular processes. We recently described a new role for VWF in controlling angiogenesis, which may have significant clinical implications for patients with Von Willebrand disease (VWD), a genetic or acquired condition caused by the deficiency or dysfunction of VWF. VWD can be associated with angiodysplasia, a condition of degenerative blood vessels often present in the gastrointestinal tract, linked to dysregulated angiogenesis. Angiodysplasia can cause severe intractable bleeding, often refractory to conventional VWD treatments. In this review we summarise the evidence showing that VWF controls angiogenesis, and review the angiogenic pathways which have been implicated in this process. We discuss the possible mechanisms though which VWF regulates angiopoietin-2 (Ang-2) and integrin αvβ3, leading to signalling through vascular endothelial growth factor receptor-2 (VEGFR2), one of the most potent activators of angiogenesis. We also review the evidence that links VWF with angiodysplasia, and how the newly identified function of VWF in controlling angiogenesis may pave the way for the development of novel therapies for the treatment of angiodysplasia in congenital VWD and in acquired conditions such as Heyde syndrome.

Heyde's syndrome: exploring the link between aortic stenosis and an acquired bleeding disorder

Heyde's syndrome was first proposed in 1958. It refers to gastrointestinal haemorrhage resulting from a combination of aortic stenosis with angiodysplasia. This report explores the case of a 93-year-old lady who was admitted to hospital following a neck of femur fracture. She suffered from multiple comorbidities including renal failure and congestive heart failure secondary to critical aortic stenosis. As an inpatient she suffered an exacerbation of both her heart and renal failure postoperatively. A week later she suffered from heavy upper gastro-intestinal bleeding, which failed to respond to pharmacological and endoscopic therapies as well as angiographic embolisation. The pathophysiology of Heyde's syndrome: an acquired von Willebrand deficiency syndrome has a much wider impact than was commonly thought, both in terms of how common it is and in how the association may be extrapolated to a wide range of bleeding disorders, rather than simply angiodysplasia associated gastrointestinal haemorrhage.

Small bowel angiodysplasia and novel disease associations: a cohort study

OBJECTIVE

Gastrointestinal angiodysplasias recurrently bleed, accounting for 3-5% of obscure gastrointestinal bleeding. The advent of small bowel capsule endoscopy (SBCE) has led to an increased recognition of small bowel angiodysplasias (SBAs) but little is known about their etiology. Previous small cohorts and case reports suggest an equal gender incidence and associations with cardiovascular disease, renal impairment, and coagulopathies.

METHODS

Patients with SBA were identified from our SBCE database. A control group, in whom gastrointestinal bleeding had been excluded, was also identified. Information on patient demographics, past medical/surgical/social history and medications was prospectively obtained.

RESULTS

A total of 82 patients and 95 controls were identified. Data was available from 81% (n = 66) of SBA patients. The mean age of patients and controls was 66.9 years (35-90) and 69.2 years (54-77), and 60% (n = 40) and 58% (n = 55) were females, respectively. There was a higher rate of all comorbidities in the SBA group 92% (61/66) versus controls 76% (72/95) p < 0.002. Significant associations were found with: hypertension (odds ratio [OR] 2.8), ischemic heart disease (OR 4.25), arrhythmias (OR 4.36), valvular heart disease (OR 18), congestive heart failure (OR 4.22), chronic kidney disease (CKD) (OR 8.4), chronic respiratory conditions (OR 2.0), and previous venous thromboembolism (VTE) (OR 6.4). Anticoagulant use was higher in patients with SBA, 50% (n = 33) versus 27% (n = 26) of controls, p < 0.002, specifically warfarin and asasantin retard.

CONCLUSIONS

SBA occurs in elderly patients with cardiovascular disease and CKD, as previously suggested. This study identifies a previously unrecognised risk in females, patients with chronic respiratory conditions and VTE, and the use of warfarin and asasantin retard. These associations should raise awareness of possible underlying SBA in risk patients with anemia.

Von Willebrand disease-associated angiodysplasia: a few answers, still many questions

The association between angiodysplasia and von Willebrand disease (VWD) has been known for more than 40 years. Bleeding in the gastrointestinal tract associated with angiodysplasia worsens the clinical course of this inherited haemorrhagic disorder and management may become difficult and challenging. Angiodysplasia associated with acquired defects or dysfunctions of von Willebrand factor (VWF) has also been reported in a variety of conditions such as monoclonal gammopathies, Heyde syndrome and in carriers of ventricular assist devices. The most recent advances concerning the mechanistic, clinical and therapeutic aspects of VWD-associated angiodysplasia are summarized in this review, together with the limitations of our knowledge that warrant further research in the frame of international cooperation.

von Willebrand factor and cancer: a renewed interest

Von Willebrand factor (VWF), the largest human plasma protein, is an adhesive multimeric glycoprotein that mediates platelet adhesion to both the subendothelial matrix and endothelial surfaces and acts as a carrier for coagulation factor VIII in the circulation. Besides its essential role in hemostasis, there is growing evidence from the literature that VWF has an additional antitumor effect, mainly by exerting negative modulation on angiogenesis and apoptosis. Current knowledge on the link between VWF and cancer is summarized in this review, based on an analysis of the most important experimental and clinical studies.

Indexes of von Willebrand factor as biomarkers of aortic stenosis severity (from the Biomarkers of Aortic Stenosis Severity [BASS] study)

We correlated von Willebrand factor (VWF) activity indexes and brain natriuretic peptide (BNP) with measures of aortic stenosis (AS) severity, bleeding, symptoms, and freedom from death or aortic valve replacement. Patients with AS (n = 66 [16 mild, 20 moderate, and 30 severe]) and aortic valve replacement (n = 21) were assessed with VWF antigen, VWF latex agglutination immunoturbidic activity, platelet function analyzer collagen plus adenosine diphosphate (PFA-CADP), VWF multimer ratio, and BNP level after echocardiography. In patients with AS, the mean gradient correlated with BNP (Spearman r = 0.29, p = 0.02), VWF latex agglutination immunoturbidic activity/VWF antigen ratio (r = -0.41, p <0.001), PFA-CADP (r = 0.49, p <0.001), and VWF multimer ratio (r = -0.76, p <0.001). The area under the curve for detection of severe AS was 0.62 (95% confidence interval [CI] 0.48 to 0.77) by elevated BNP, 0.81 (95% CI 0.69 to 0.92) by PFA-CADP closure time, 0.69 (95% CI 0.55 to 0.82) by VWF latex agglutination immunoturbidic activity/VWF antigen ratio, and 0.86 (95% CI 0.76 to 0.95) by VWF multimer ratio. For the VWF multimer ratio, a threshold of 0.15 yielded a sensitivity and specificity for severe AS of 77% and positive predictive value of 74%. Bleeding (in 14%) was associated with a prolonged PFA-CADP time and reduced VWF latex agglutination immunoturbidic activity/VWF antigen ratio. Symptoms were associated with elevated BNP and low Duke Activity Status Index score. In 66 patients with AS, freedom from death (n = 4) or aortic valve replacement (n = 22) was associated with PFA-CADP (p = 0.003), VWF high-molecular-weight multimers (p = 0.009), and VWF latex agglutination immunoturbidic activity/VWF antigen ratio (p <0.001) but not BNP (p = 0.32). In severe AS versus aortic valve replacement, the PFA-CADP and VWF multimer ratio differed (p <0.001), but BNP and the VWF latex agglutination immunoturbidic activity/VWF antigen ratio did not. In conclusion, the VWF activity indexes were associated with AS severity and bleeding and were predictive of cardiovascular outcomes.

Aortic Valvuloplasty as Bridging for TAVI in High-Risk Patients with Heyde's Syndrome: A Case Report

There is a frequent association between aortic valve stenosis and gastrointestinal bleeding, also known as Heyde's syndrome. In these patients, the aortic valve replacement should be recommended as “gold standard.” In high-surgical-risk patients, the Transcatheter Aortic Valve Implantation (TAVI) is an alternative option. However, the risk of bleeding recurrence, related to double antiplatelet therapy started after TAVI, cannot be excluded especially in the first months. We present a case of a patient with a severe aortic valve stenosis and a history of previously documented angiodysplasia and recurrence of gastrointestinal bleeding initially treated only with balloon aortic valvuloplasty that excluded recurrence of bleeding during the subsequent six months of followup. Therefore, a definite transfemoral Edwards XT valve implantation was planned to be performed in case of recurrence of aortic stenosis.

von Willebrand factor, shear stress, and ADAMTS13 in hemostasis and thrombosis

von Willebrand factor (VWF), an adhesive glycoprotein whose deficiency is best known for causing bleeding in patients with von Willebrand disease (VWD), is a complex molecule with a myriad of mysterious properties including its dependence on shear stress for adhesive functions. The discovery of ADAMTS13 has provided a critical impetus for understanding the regulation of VWF activity by shear stress. This communication reviews the current knowledge in VWF homeostasis and illustrates how this knowledge may help understand the changes affecting patients with various conditions including thrombotic thrombocytopenic purpura, VWD, hemolytic uremic syndrome, aortic stenosis, and ventricular assist devices.

Capsule endoscopy findings in patients with occult or overt bleeding older than 80 years

BACKGROUND

  Overt and occult bleeding are the main indications for a wireless capsule endoscopy (WCE) study of the small bowel. Most published studies omit patients aged over 80.

AIM

  To determine whether WCE is feasible in patients with overt or occult bleeding over age 80 and to define the spectrum of small bowel pathologies in this age group.

PATIENTS AND METHODS

  In a retrospective non-randomized tertiary care study, 60 patients at least 80 years or older (aged group) and 120 matched patients aged <80 years (younger group) with overt or occult bleeding (including iron deficiency anaemia) and no significant gastroscopic or colonoscopic findings underwent WCE.

RESULTS

  Of the 180 patients, 46 (77%) patients in the aged group and 97 (81%) in the younger group successfully completed small bowel study (P = 0.51). There was no difference in gastric transit time and small bowel passing time between the two groups. More patients in the aged group (48 cases, 80%) than the younger group (56 cases, 47%) presented with small bowel angiodysplasias (P < 0.0001). Nevertheless, there was no difference between the two groups concerning ulcerative and neoplastic lesions. No patient presented with capsule impaction, but more patients in the aged group (35 cases, 58%) than in the younger group (10 cases, 8%) found the study difficult and tiresome (P < 0.001). Preparation validation was poor in 34% of small bowel lumen in the aged group and 19% in the younger group (P = 0.03).

CONCLUSION

  WCE is feasible, although rather tiresome, in patients over the age of 80. Though the vast majority of patients older than 80 presented with angiodysplasias, there were no differences between the aged and younger groups in the presence of ulcerative lesions and polyps or tumors.

Pathophysiology of acquired von Willebrand disease: a concise review

Acquired von Willebrand disease (AVWD) is a rare, underdiagnosed hemorrhagic disorder, which is similar to congenital VWD with regard to the clinical and laboratory parameters; however, it is found in individuals with no positive family history and has no genetic basis. The etiology is varied, the commonest being hematoproliferative disorders and cardiovascular disorders. Other disorders associated with AVWD are autoimmune disorders such as systematic lupus erythematosus, hypothyroidism, and neoplasia, or it may also be drug induced. In quite a few cases, the etiology is unknown. The pathogenic mechanisms are different in different underlying disorders or they may be overlapping among these disorders. Some of the proposed mechanisms include the development of autoantibodies, selective absorption of high molecular weight von Willebrand factor (VWF) multimers, non-selective absorption of VWF, mechanical destruction of VWF under high shear stress, and increased proteolysis. This report presents a concise review of the pathophysiological mechanisms of AVWD in these various underlying conditions.

Acquired von Willebrand syndrome and mitral valve prosthesis leakage. A pilot study

BACKGROUND

Of patients with severe aortic stenosis, 15-25% present with bleeding episodes possibly attributable to acquired von Willebrand syndrome (AVWS). AVWS associated with mitral valve prosthesis leakage has not been reported.

METHODS AND RESULTS

Five patients receiving appropriate oral anticoagulation showed mitral valve prosthesis leakage and bleeding episodes; all of them required hospitalization and two blood transfusions, and a von Willebrand factor (VWF) analysis was performed. Two patients with normal functioning metallic prosthesis valves were included as controls. Before surgery, after cessation of acenocumarol, the patients had prolonged activated partial thromboplastin time; four had prolonged closure time (CT) from the platelet function analyzer. Factor VIII procoagulant activity (FVIII:C), VWF ristocetin cofactor activity (VWF:RCo), and VWF collagen binding (VWF:CB) were considerably elevated, while VWF antigen (VWF:Ag) was most elevated. Disproportionate VWF:RCo/VWF:Ag and VWF:CB/VWF:Ag ratios were seen with the loss of large VWF multimers. Following surgery, all parameters were markedly increased and the ratios, CT, and multimeric VWF profile became normal.

CONCLUSIONS

Acquired VWF qualitative alterations in mitral valve prosthesis leakage may be associated with or contribute to bleeding diathesis. AVWS should be taken into consideration in patients with mitral valve prosthesis leakage with bleeding diathesis not explained by excessive oral anticoagulation.

How I treat the acquired von Willebrand syndrome

The acquired von Willebrand syndrome (AVWS) is a bleeding disorder that is frequently unrecognized or is misdiagnosed as von Willebrand disease. AVWS is characterized by structural or functional defects of von Willebrand factor (VWF) that are secondary to autoimmune, lymphoproliferative or myeloproliferative, malignant, cardiovascular, or other disorders. VWF abnormalities in these disorders can result from (1) antibody-mediated clearance or functional interference, (2) adsorption to surfaces of transformed cells or platelets, or (3) increased shear stress and subsequent proteolysis. Diagnosis can be challenging as no single test is usually sufficient to prove or exclude AVWS. Furthermore, there are no evidence-based guidelines for management. Treatments of the underlying medical condition, including chemo/radiotherapy, surgery, or immunosuppressants can result in remission of AVWS, but is not always feasible and successful. Because of the heterogeneous mechanisms of AVWS, more than one therapeutic approach is often required to treat acute bleeds and for prophylaxis during invasive procedures; the treatment options include, but are not limited to, desmopressin, VWF-containing concentrates, intravenous immunoglobulin, plasmapheresis or recombinant factor VIIa. Here, we review the management of AVWS with an overview on the currently available evidence and additional considerations for typical treatment situations.

Do clinical characteristics predict the presence of small bowel angioectasias on capsule endoscopy?

BACKGROUND AND AIMS

Angioectasias (AVMs) are the most common vascular anomaly of the gastrointestinal (GI) tract, and these lesions are often associated with obscure gastrointestinal bleeding (OGIB). It is unknown if the presence of upper and/or lower gastrointestinal AVMs are predictive of small bowel AVMs. The aims of this study are to define the small bowel segmental distribution of AVMs and to identify the factors predicting the presence of small bowel AVMs among a cohort of patients with a known history of AVMs in the upper and/or lower GI tracts who are undergoing capsule endoscopy (CE) for OGIB.

METHODS

We performed a retrospective cohort analysis of 1,125 patients undergoing CE at our institution between 11/1/2001 and 8/31/2007. Inclusion criteria were: (1) complete esophagoduodenoscopy (EGD), CE, and colonoscopy, (2) OGIB indication for CE, and (3) history of ≥ 1 AVM on EGD and/or colonoscopy that was previously treated in the past or deemed not to be a clinically significant source of bleeding. Exclusion criteria were: (1) history of radiation therapy to the GI tract, and (2) presence of a congenital or systemic disease associated with GI AVMs. Data were extracted on: (1) age; (2) gender; (3) presence of diabetes, (4) presence of hypertension, (5) presence of aortic stenosis, (6) history of non-steroidal anti-inflammatory therapy, (7) history of anticoagulant therapy, (8) hemoglobin, platelet, and INR values prior to CE; (9) baseline serum creatinine; and (10) presence and GI tract segmental location of AVMs. Multivariate logistic regression was used to identify independent predictors of small bowel AVMs.

RESULTS

1,125 patients underwent EGD, CE, and colonoscopy. One hundred and fourteen patients had a history of ≥ 1 AVM on EGD and/or colonoscopy and met inclusion and exclusion criteria. The mean age was 69 years, and 63% of patients were women. 37% of patients were found to have ≥ 1 jejunal AVM and 15% were found to have ≥ 1 ileal AVM. In multivariate analysis, age ≥ 65 (OR 2.62, P = 0.05) and the presence of AVMs on EGD (OR 4.61, P = 0.02) were predictive of jejunal AVMs. AVMs on colonoscopy alone were not predictive of jejunal or ileal AVMs. No factors were found to predict the presence of ileal AVMs.

CONCLUSIONS

Patients with AVMs on EGD have an increased risk of jejunal AVMs on CE, particularly if they are elderly. Future studies should validate these findings in a prospective cohort.

Hypertrophic obstructive cardiomyopathy, bleeding history, and acquired von Willebrand syndrome: response to septal myectomy

Bleeding with severe aortic stenosis is linked to acquired von Willebrand syndrome and loss of high-molecular-weight multimers of von Willebrand factor. Valve replacement resolves bleeding tendency and loss of high-molecular-weight multimers. We report outcomes in 5 patients with symptomatic obstructive hypertrophic cardiomyopathy and spontaneous gastrointestinal, mucosal, or excessive postsurgical bleeding in whom acquired von Willebrand syndrome was documented. All 5 patients underwent surgical septal myectomy with resolution of acquired von Willebrand syndrome.

Management options to treat gastrointestinal bleeding in patients supported on rotary left ventricular assist devices: a single-center experience

Gastrointestinal (GI) bleeding in ventricular assist devices (VADs) has been reported with rotary devices. The pathophysiological mechanisms and treatments are in evolution. We performed a retrospective review of GI bleeding episodes for all VADs implanted at our institution. Five male patients experienced GI bleeding-age 63.6 ± 3.64 years. VAD type VentrAssist n = 1, Jarvik 2000 n = 2, and HeartWare n = 2. All patients were anticoagulated as per protocol with antiplatelet agents (aspirin and/or clopidogrel bisulfate [Plavix] and warfarin (therapeutic international normalized ratio 2.0-3.5). There was no prior history of gastric bleeding in this group. Ten episodes of bleeding requiring blood transfusion occurred in five patients. Some patients had multiple episodes (1 × 5, 1 × 2, 3 × 1). The events occurred at varying times post-VAD implantation (days 14, 21, 26, 107, 152, 189, 476, 582, 669, and 839). Octreotide (a long-acting somatostatin analogue that reduces splanchnic arterial and portal blood flow) was administered subcutaneously or intravenously. Three patients received infusions of adrenaline at 1 µg/min to enhance pulsatility. Anticoagulation was interrupted during bleeding episodes but successfully introduced post bleeding event. GI bleeding is a significant complication of VAD therapy. In this article, we discuss diagnosis and management options.