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

Redefining hyperviscosity in acute leukemia: Potential implications for red cell transfusions in the microvasculature

Hyperleukocytosis is an emergency of acute leukemia leading to blood hyperviscosity, potentially resulting in life-threatening microvascular obstruction, or leukostasis. Due to the high number of red cells in the circulation, hematocrit/hemoglobin levels (Hct/Hgb) are major drivers of blood viscosity, but how Hct/Hgb mediates hyperviscosity in acute leukemia remains unknown. In vivo hemorheological studies are difficult to conduct and interpret due to issues related to visualizing and manipulating the microvasculature. To that end, a multi-vessel microfluidic device recapitulating the size-scale and geometry of the microvasculature was designed to investigate how Hct/Hgb interacts with acute leukemia to induce "in vitro" leukostasis. Using patient samples and cell lines, the degree of leukostasis was different among leukemia immunophenotypes with respect to white blood cell (WBC) count and Hct/Hgb. Among lymphoid immunophenotypes, severe anemia is protective against in vitro leukostasis and Hct/Hgb thresholds became apparent above which in vitro leukostasis significantly increased, to a greater extent with B-cell acute lymphoblastic leukemia (ALL) versus T-cell ALL. In vitro leukostasis in acute myeloid leukemia was primarily driven by WBC with little interaction with Hct/Hgb. This sets the stage for prospective clinical studies assessing how red cell transfusion may affect leukostasis risk in immunophenotypically different acute leukemia patients.

A career in solving clinical-pathological conundrums: Heyde syndrome, anti-platelet factor 4 disorders, and microvascular limb ischemic necrosis

Hematology is a clinical specialty with strong roots in the laboratory; accordingly, the lab can help solve perplexing clinical problems. This review highlights clinical-pathological conundrums addressed during my 35-year hematology career at McMaster University. Heyde syndrome is the association between aortic stenosis and bleeding gastrointestinal (GI) angiodysplasia where the bleeding is usually cured by aortic valve replacement; the chance reading of a neonatal study showing reversible deficiency of high-molecular-weight (HMW) multimers of von Willebrand factor (vWF) following surgical correction of congenital heart disease provided the key insight that a subtle deficiency of HMW multimers of vWF explains Heyde syndrome. The unusual immunobiology of heparin-induced thrombocytopenia (HIT)-a highly prothrombotic, antibody-mediated, anti-platelet factor 4 (PF4) disorder featuring rapid appearance and then disappearance (seroreversion) of the pathological heparin-dependent platelet-activating antibodies-permitted identification of key clinical features that informed development of a scoring system (4Ts) to aid in HIT diagnosis. Atypical clinical presentations of HIT prompted identification of heparin-independent anti-PF4 antibodies, now recognized as the explanation for vaccine-induced immune thrombotic thrombocytopenia (VITT), as well as VITT-like disorders triggered by adenovirus infection. Another unusual feature of HIT is its strong association with limb ischemia, including limb necrosis secondary to deep-vein/microvascular thrombosis (venous limb gangrene). The remarkable observation that supratherapeutic warfarin anticoagulation predisposes to HIT- and cancer-associated venous limb gangrene provided insight into disturbed procoagulant/anticoagulant balance; these concepts are relevant to microvascular thrombosis in critical illness (symmetrical peripheral gangrene), including a pathophysiological role for proximate "shock liver" (impaired hepatic synthesis of natural anticoagulants).

Thromboxane biosynthesis and future events in diabetes: the ASCEND trial

BACKGROUND AND AIMS

Thromboxane (TX) A2, released by activated platelets, plays an important role in atherothrombosis. Urinary 11-dehydro-TXB2 (U-TXM), a stable metabolite reflecting the whole-body TXA2 biosynthesis, is reduced by ∼70% by daily low-dose aspirin. The U-TXM represents a non-invasive biomarker of in vivo platelet activation and is enhanced in patients with diabetes. This study assessed whether U-TXM is associated with the risk of future serious vascular events or revascularizations (SVE-R), major bleeding, or cancer in patients with diabetes.

METHODS

The U-TXM was measured pre-randomization to aspirin or placebo in 5948 people with type 1 or 2 diabetes and no cardiovascular disease, in the ASCEND trial. Associations between log U-TXM and SVE-R (n = 618), major bleed (n = 206), and cancer (n = 700) during 6.6 years of follow-up were investigated by Cox regression; comparisons of these associations with the effects of randomization to aspirin were made.

RESULTS

Higher U-TXM was associated with older age, female sex, current smoking, type 2 diabetes, higher body size, urinary albumin/creatinine ratio of ≥3 mg/mmol, and higher estimated glomerular filtration rate. After adjustment for these, U-TXM was marginally statistically significantly associated with SVE-R and major bleed but not cancer [hazard ratios per 1 SD higher log U-TXM (95% confidence interval): 1.09 (1.00-1.18), 1.16 (1.01-1.34), and 1.06 (0.98-1.14)]. The hazard ratio was similar to that implied by the clinical effects of randomization to aspirin for SVE-R but not for major bleed.

CONCLUSIONS

The U-TXM was log-linearly independently associated with SVE-R in diabetes. This is consistent with the involvement of platelet TXA2 in diabetic atherothrombosis.

How I treat von Willebrand disorders in older adults

ABSTRACT

von Willebrand disease (VWD) is the most common bleeding disorder and especially milder type 1 VWD might not be cared for in specialty clinics. VW factor levels rise with age, but the rise of these levels does not necessarily correlate with bleeding risk. A recent bleeding history combined with recent labs are important for hemostatic management decision during surgical interventions. Antifibrinolytics appear safe in the population of older adults, whereas desmopressin (DDAVP) should be used cautiously. Where needed, factor concentrates present a great treatment option. Acquired von Willebrand syndrome is vastly underrecognized, but likely to surface in the aging, especially in the setting of comorbidities, such as plasma-cell dyscrasias. Intravenous immunoglobulin can be an effective treatment in this scenario, but potentially increases thrombotic risk.

Enteroscopy versus Video Capsule Endoscopy for Automatic Diagnosis of Small Bowel Disorders-A Comparative Analysis of Artificial Intelligence Applications

BACKGROUND

Small bowel disorders present a diagnostic challenge due to the limited accessibility of the small intestine. Accurate diagnosis is made with the aid of specific procedures, like capsule endoscopy or double-ballon enteroscopy, but they are not usually solicited and not widely accessible. This study aims to assess and compare the diagnostic effectiveness of enteroscopy and video capsule endoscopy (VCE) when combined with artificial intelligence (AI) algorithms for the automatic detection of small bowel diseases.

MATERIALS AND METHODS

We performed an extensive literature search for relevant studies about AI applications capable of identifying small bowel disorders using enteroscopy and VCE, published between 2012 and 2023, employing PubMed, Cochrane Library, Google Scholar, Embase, Scopus, and ClinicalTrials.gov databases.

RESULTS

Our investigation discovered a total of 27 publications, out of which 21 studies assessed the application of VCE, while the remaining 6 articles analyzed the enteroscopy procedure. The included studies portrayed that both investigations, enhanced by AI, exhibited a high level of diagnostic accuracy. Enteroscopy demonstrated superior diagnostic capability, providing precise identification of small bowel pathologies with the added advantage of enabling immediate therapeutic intervention. The choice between these modalities should be guided by clinical context, patient preference, and resource availability. Studies with larger sample sizes and prospective designs are warranted to validate these results and optimize the integration of AI in small bowel diagnostics.

CONCLUSIONS

The current analysis demonstrates that both enteroscopy and VCE with AI augmentation exhibit comparable diagnostic performance for the automatic detection of small bowel disorders.

Inpatient Outcomes of Gastric Antral Vascular Ectasia in Those With Aortic Stenosis: A Retrospective Study of 85,000 Hospitalizations

GOALS

To investigate the outcomes of hospitalized patients with gastric antral vascular ectasia (GAVE) in the setting of aortic stenosis (AS).

BACKGROUND

Although AS is associated with gastrointestinal arteriovenous malformations, its association with GAVE, a rare cause of upper gastrointestinal bleeding, remains unknown.

STUDY

The National Inpatient Sample database from the years 2016 to 2019 was searched for patients admitted with a diagnosis of GAVE, with and without a history of AS. Univariate and multivariate logistic regression analysis was performed to determine the risk of mortality and in-hospital complications in the GAVE/AS group compared with the GAVE-only group.

RESULTS

Patients with AS had a 2-fold increase in the risk of GAVE [odds ratio (OR): 2.08, P < 0.001], with no statistically significant difference in inpatient mortality between the study groups (OR: 1.36, P = 0.268). Patients with GAVE-AS had a higher risk of hypovolemic shock (OR: 2.00, P = 0.001) and acute coronary syndromes (OR: 2.25, P < 0.001) with no difference in risk of cardiogenic shock (P = 0.695), acute kidney injury (P = 0.550), blood transfusion (P = 0.270), sepsis (P = 0.598), respiratory failure (P = 0.200), or in-hospital cardiac arrest (P = 0.638). The cost of care in patients with GAVE-AS was increased by a mean of $4729 (P = 0.022), with no increase in length of stay (P = 0.320) when compared with patients with GAVE-only.

CONCLUSIONS

Patients with AS have a 2-fold increase in the risk of development of GAVE. Patients with AS admitted for GAVE-related bleeding are at higher rates of hypovolemic shock, acute coronary syndrome, and higher resource utilization when compared with admitted patients with GAVE without AS.

Concern for Increased Prevalence of Heyde's Syndrome in Patients on Hemodialysis

The association between aortic stenosis and increased gastrointestinal arteriovenous malformations is known as Heyde's syndrome. An acquired von Willebrand deficiency mediates the connection between these two seemingly dispersed pathologies. As von Willebrand factor passes through a stenosed aorta, it is broken down and can no longer inhibit angiogenesis, leading to angiodysplasias. Heyde's syndrome can manifest with chronic, refractory anemia requiring multiple hospitalizations for symptomatic gastrointestinal bleeding and transfusion. Hitherto, Heyde's syndrome has been considered exceptionally rare, with 1-3% of populations with aortic stenosis. However, given that 31.7% of patients with gastrointestinal angioplasty have aortic stenosis and gastrointestinal arteriovenous malformations are not screened for in patients without anemia, the prevalence of Heyde's syndrome is most likely higher than currently reflected in the literature. Also, the prevalence of Heyde's syndrome in populations who are predisposed to angiodysplasias, such as those on hemodialysis, is understudied. We aim to impart a need for increased research on the prevalence of Heyde's syndrome, especially in high-risk patients. This case report presents a patient with severe Heyde's syndrome on hemodialysis, showing an unconsidered risk factor for Heyde's syndrome in need of further research.

Beyond Acquired Von Willebrand Deficiency: Exploring Alternative Mechanisms of Heyde's Syndrome

Heyde's syndrome (HS) is a complex condition characterized by the coexistence of severe aortic stenosis (AS) and gastrointestinal (GI) angiodysplasia. The prevailing belief has been that acquired von-Willebrand factor deficiency (AVWD) is the underlying cause of HS. However, the validity of this theory remains contentious, as there have been reports of bleeding angiodysplasia in the setting of AS despite normal von-Willebrand factor (vWF) activity. Here, we present a compelling case of HS with negative diagnostic testing for AVWD. A 61-year-old female with a history of end-stage renal disease on hemodialysis, AS, and a history of recurrent GI bleeding presented with dyspnea. Prior to arrival, she reported multiple episodes of melena and hematochezia and was found to have a hemoglobin of 6 g/dL. Notable exam findings included melenic stool on digital rectal exam and a grade three systolic crescendo-decrescendo murmur that radiated up to the carotids. A transthoracic echocardiogram demonstrated evidence of severe AS. Considering the recurrent GI bleeding and severe AS, HS was suspected. To investigate this further, a vWF disease panel was sent, revealing a normal multimeric pattern. Given hemodynamic stability, she was discharged but had multiple readmissions soon after with recurrent GI bleeding requiring endoscopic intervention. On her last visit, she underwent transcatheter aortic valve replacement (TAVR) with notable resolution in her GI bleeds thereafter. The prevailing theory regarding the etiology of HS is acquired vWF deficiency. However, the validity of this theory remains a topic of debate, as a growing body of evidence suggests that the absence of AVWD does not necessarily rule out the diagnosis. The absence of AVWD in our patient raises questions about its prevalence in HS and its status as a key feature and highlights the importance of considering HS events without AVWD, given the risk of recurrent life-threatening GI bleeds.

Red blood cell sublethal damage: haemocompatibility is not the absence of haemolysis

Blood is a complex fluid owing to its two-phase suspension of formed cellular elements within a protein-rich plasma. Vital to its role in distributing nutrients throughout the circulatory system, the mechanical properties of blood - and particularly red blood cells (RBC)-primarily determine bulk flow characteristics and microcirculatory flux. Various factors impair the physical properties of RBC, including cellular senescence, many diseases, and exposure to mechanical forces. Indeed, the latter is increasingly relevant following the advent of modern life support, such as mechanical circulatory support (MCS), which induce unique interactions between blood and artificial environments that leave blood cells with the signature of aging, albeit accelerated, and crucially underlie various serious complications, including death. Accumulating evidence indicates that these complications appear to be associated with mechanical shear forces present within MCS that are not extreme enough to overtly rupture cells, yet may still induce "sublethal" injury and "fatigue" to vital blood constituents. Impaired RBC physical properties following elevated shear exposure-a hallmark of sublethal injury to blood-are notable and may explain, at least in part, systemic complications and premature mortality associated with MCS. Design of optimal next-generation MCS devices thus requires consideration of biocompatibility and blood-device interactions to minimize potential blood complications and promote clinical success. Presented herein is a contemporary understanding of "blood damage," with emphasis on shear exposures that alter microrheological function but do not overtly destroy cells (ie, sublethal damage). Identification of key cellular factors perturbed by supraphysiological shear exposure are examined, offering potential pathways to enhance design of MCS and blood-contacting medical devices.

Hyperviscosity syndromes; hemorheology for physicians and the use of microfluidic devices

PURPOSE OF REVIEW

Hyperviscosity syndromes can lead to significant morbidity and mortality. Existing methods to measure microcirculatory rheology are not readily available and limited in relevance and accuracy at this level. In this review, we review selected hyperviscosity syndromes and the advancement of their knowledge using microfluidic platforms.

RECENT FINDINGS

Viscosity changes drastically at the microvascular level as the physical properties of the cells themselves become the major determinants of resistance to blood flow. Current, outdated viscosity measurements only quantify whole blood or serum. Changes in blood composition, cell number, or the physical properties themselves lead to increased blood viscosity. Given the significant morbidity and mortality from hyperviscosity syndromes, new biophysical tools are needed and being developed to study microvascular biophysical and hemodynamic conditions at this microvascular level to help predict those at risk and guide therapeutic treatment.

SUMMARY

The use of 'lab-on-a-chip' technology continues to rise to relevance with point of care, personalized testing and medicine as customizable microfluidic platforms enable independent control of many in vivo factors and are a powerful tool to study microcirculatory hemorheology.

Use of Diagnosis Codes to Find Blood Transfusion Adverse Events in Electronic Health Records

OBJECTIVE

Electronic health records (EHRs) and big data tools offer the opportunity for surveillance of adverse events (patient harm associated with medical care). We used International Classification of Diseases, Ninth Revision, codes in electronic records to identify known, and potentially novel, adverse reactions to blood transfusion.

METHODS

We used 49,331 adult admissions involving critical care at a major teaching hospital, 2001-2012, in the Medical Information Mart for Intensive Care III EHRs database. We formed a T (defined as packed red blood cells, platelets, or plasma) group of 21,443 admissions versus 25,468 comparison (C) admissions. The International Classification of Diseases, Ninth Revision, Clinical Modification , diagnosis codes were compared for T versus C, described, and tested with statistical tools.

RESULTS

Transfusion adverse events (TAEs) such as transfusion-associated circulatory overload (TACO; 12 T cases; rate ratio [RR], 15.61; 95% confidence interval [CI], 2.49-98) were found. There were also potential TAEs similar to TAEs, such as fluid overload disorder (361 T admissions; RR, 2.24; 95% CI, 1.88-2.65), similar to TACO. Some diagnoses could have been sequelae of TAEs, including nontraumatic compartment syndrome of abdomen (52 T cases; RR, 6.76; 95% CI, 3.40-14.9) possibly being a consequence of TACO.

CONCLUSIONS

Surveillance for diagnosis codes that could be TAE sequelae or unrecognized TAE might be useful supplements to existing medical product adverse event programs.

Impact of hepatopulmonary syndrome in liver transplantation candidates and the role of angiogenesis

BACKGROUND

Hepatopulmonary syndrome affects 10-30% of patients with cirrhosis and portal hypertension. We evaluated the serum angiogenic profile of hepatopulmonary syndrome and assessed the clinical impact of hepatopulmonary syndrome in patients evaluated for liver transplantation.

METHODS

The Pulmonary Vascular Complications of Liver Disease 2 study was a multicentre, prospective cohort study of adults undergoing their first liver transplantation evaluation. Hepatopulmonary syndrome was defined as an alveolar-arterial oxygen gradient ≥15 mmHg (≥20 mmHg if age >64 years), positive contrast-enhanced transthoracic echocardiography and absence of lung disease.

RESULTS

We included 85 patients with hepatopulmonary syndrome and 146 patients without hepatopulmonary syndrome. Patients with hepatopulmonary syndrome had more complications of portal hypertension and slightly higher Model for End-Stage Liver Disease-Na score compared to those without hepatopulmonary syndrome (median (interquartile range) 15 (12-19) versus 14 (10-17), p=0.006). Hepatopulmonary syndrome patients had significantly lower 6-min walk distance and worse functional class. Hepatopulmonary syndrome patients had higher circulating angiopoietin 2, Tie2, tenascin C, tyrosine protein kinase Kit (c-Kit), vascular cell adhesion molecule 1 and von Willebrand factor levels, and lower E-selectin levels. Patients with hepatopulmonary syndrome had an increased risk of death (hazard ratio 1.80, 95% CI 1.03-3.16, p=0.04), which persisted despite adjustment for covariates (hazard ratio 1.79, 95% CI 1.02-3.15, p=0.04). This association did not vary based on levels of oxygenation, reflecting the severity of hepatopulmonary syndrome.

CONCLUSION

Hepatopulmonary syndrome was associated with a profile of abnormal systemic angiogenesis, worse exercise and functional capacity, and an overall increased risk of death.

Sixth Åland Island Conference on von Willebrand disease

Introduction

The sixth Åland Islands Conference on von Willebrand disease (VWD) on the Åland Islands, Finland, was held from 20 to 22 September 2018.

Aim

The meeting brought together experts in the field of VWD from around the world to share the latest advances and knowledge in VWD.

Results and discussion

The topics covered both clinical aspects of disease management, and biochemical and laboratory insights into the disease. The clinical topics discussed included epidemiology, diagnosis and treatment of VWD in different countries, management of children with VWD, bleeding control during surgery, specific considerations for the management of type 3 VWD and bleeding control in women with VWD. Current approaches to the management of acquired von Willebrand syndrome were also discussed. Despite significant advances in the understanding and therapeutic options for VWD, there remain many challenges to be overcome in order to optimise patient care. In comparison with haemophilia A, there are very few registries of VWD patients, which would be a valuable source of data on the condition and its management. VWD is still underdiagnosed, and many patients suffer recurrent or severe bleeding that could be prevented. Awareness of VWD among healthcare practitioners, including non‐haematologists, should be improved to allow timely diagnosis and intervention. Diagnosis remains challenging, and the development of fast, simple assays may help to facilitate accurate and rapid diagnosis of VWD.

Comparison Between Intravenous and Intramuscular Octreotide in the Management of Heyde’s Syndrome

Heyde’s syndrome is defined as a triad of aortic stenosis, anemia due to angiodysplasia-related bleeding, and von Willebrand syndrome type 2A. It is a rare disease and a diagnostic challenge. Treatment modalities include symptomatic management, blood transfusions, aortic valve replacement, and medications such as octreotide. Here, we report the case of a patient who was resistant to symptomatic management, aortic valve replacement, as well as intravenous octreotide.

Recurrent Gastrointestinal Bleeding in a Middle-Aged Man

Acquired von Willebrand disease (avWD) arises because of mechanisms that destroy, decrease, absorb, or clear von Willebrand factor (vWF). A 59-year-old man presented with a 3-year history of recurrent gastrointestinal bleeding. Laboratory workup revealed a prolonged platelet function assay-100. The vWF antigen was decreased, and a low vWF immunofunctional activity/antigen ratio, low collagen binding/antigen ratio, and decreased intermediate and high molecular weight multimers were noted. The patient had no high-shear stress conditions, and an antibody-mediated process was suspected. A vWF mixing study showed complete correction of vWF activity, suggesting no direct functional inhibitor. The patient was given a bolus of vWF concentrate with serial measurements of vWF; the vWF half-life was 2.5 hours. The vWF propeptide/antigen ratio was 4:1, supporting a diagnosis of aVWD resulting from increased antibody-mediated vWF clearance. This case study emphasizes the laboratory’s role in the diagnosis and treatment of rare, overlooked acquired bleeding disorders.

Reappraising the spectrum of bleeding gastrointestinal angioectasia in a degenerative calcific aortic valve stenosis: Heyde’s syndrome

Background

The occurrence of bleeding gastrointestinal angioectasia in elderly patients with degenerative calcific aortic stenosis is one of the most challenging clinical scenarios. A number of studies have shown that this clinical phenomenon is known as Heyde’s syndrome.

Main body of the abstract

The pathogenesis of Heyde’s syndrome is mainly due to the loss of high-molecular-weight von Willebrand factor (HMW vWF) multimers, as a consequent fragmentation of HMW vWF multimers as they pass through the stenosed aortic valve leading to acquired von Willebrand syndrome type IIA. Aortic valve replacement has proven to be a more effective management approach in the cessation of recurrent episodes of gastrointestinal bleeding.

Short conclusion

Physicians should have a high index of suspicion when dealing with elderly patients with established aortic stenosis presenting with iron deficiency anemia or unclear gastrointestinal bleeding. Parallel consultations between different specialties are essential for appropriate management.

Aortic stenosis and Heyde’s syndrome: A comprehensive review

Heyde’s syndrome is an under reported systemic disease of gastrointestinal and cardiac manifestation in older adults. It is characterized by a triad of aortic stenosis, angiodysplasia with bleeding and acquired von Willebrand syndrome. It is characterized by proteolysis of high molecular weight multimers of von Willebrand Factor and loss of platelet mediated homeostasis. Heyde’s syndrome is a treatable condition in most cases, especially in the current era of evolution in interventional cardiology and gastroenterology. There are currently no established guidelines in the management of this condition due to paucity of high quality studies, which warrant future trials. High index of suspicion and increasing the awareness of the syndrome among the general practitioners and sub-specialists will improve the diagnostic potential of Heyde’s syndrome. Future studies may change the management aspect of Heyde's syndrome and pave a path for drawing specific guidelines and algorithms. The aim of our review article is to summarize the basic pathophysiology, diagnostics and management of Heyde’s syndrome with a special attention to Transcatheter aortic valve replacement.

Aortic Valve Stenosis, a Precipitating Factor of Recurrent Bleed in Colonic Angiodysplasia: A Literature Review

Angiodysplasia (also known as angioectasia) is a lesion characterized by abnormal, dilated small blood vessels in the mucosa and submucosal layers of the GI tract. With the estimated low incidence of active GI bleeding from these lesions, angiodysplasia can be challenging to diagnose. The presence of aortic stenosis has increased the recognition rate of angiodysplasia, especially in the elderly. Despite the associations between aortic stenosis and angiodysplasia (Heyde's syndrome) revealed in several studies, the etiology of Heyde syndrome is still debatable, which has led to the proposition of several hypotheses that are reviewed in this article. This activity will help review the meaning of Heyde's syndrome, epidemiology, proposed pathophysiology, diagnosis, and management by surveying articles published between 1955 and 2021 on PubMed. We used search terms such as "colonic angiodysplasia," "arteriovenous malformation," "Heyde syndrome," "refractory gastrointestinal bleed," "aortic valve stenosis," and "acquired von Willebrand disease." Findings revealed an association between aortic stenosis and lower gastrointestinal (GI) bleed.

Heyde syndrome: prevalence and outcomes in patients undergoing transcatheter aortic valve implantation

Background

Heyde syndrome (HS) is known as the association of severe aortic stenosis (AS) and recurrent gastrointestinal bleeding (GIB) from angiodysplasia. Data on the prevalence of HS and results after TAVI remain scarce.

Methods

2548 consecutive patients who underwent TAVI for the treatment of AS from 2008 to 2017 were evaluated for a history of GIB and the presence of HS. The diagnosis of HS was defined as a clinical triad of severe AS, a history of recurrent GIB, and an endoscopic diagnosis of angiodysplasia. These patients (Heyde) were followed to investigate clinical outcomes, bleeding complications and the recurrence of GIB and were compared to patients with GIB unrelated to HS (Non-Heyde).

Results

A history of GIB prior to TAVI was detected in 190 patients (7.5%). Among them, 47 patients were diagnosed with HS (1.8%). Heyde patients required blood transfusions more frequently compared to Non-Heyde patients during index hospitalization (50.0% vs. 31.9%, p = 0.03). Recurrent GIB was detected in 39.8% of Heyde compared to 21.2% of Non-Heyde patients one year after TAVI (p = 0.03). In patients diagnosed with HS and recurrent GIB after TAVI, the rate of residual ≥ mild paravalvular leakage (PVL) was higher compared to those without recurrent bleeding (73.3% vs. 38.1%, p = 0.05).

Conclusion

A relevant number of patients undergoing TAVI were diagnosed with HS. Recurrent GIB was detected in a significant number of Heyde patients during follow-up. A possible association with residual PVL requires further investigation to improve treatment options and outcomes in patients with HS.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00392-021-01905-z.

Recurrent Gastrointestinal Bleeding in a Patient With Severe Aortic Valve Stenosis: A Diagnosis of Heyde's Syndrome

Heyde's syndrome is defined as the coexistence of aortic valve stenosis (AS) and recurrent gastrointestinal (GI) bleeding from intestinal angiodysplasia (IA). Despite the fact that Heyde's syndrome was first described decades ago, the association between AS and IA remains frequently unidentified, and thus, a high clinical suspicion is needed for its diagnosis. Here we present a case of a 60-year-old man with a history of severe AS, who presented with recurrent GI bleeding and was found to have multiple intestinal angioectasias on endoscopy.

Perspectives on Heyde's Syndrome and Calcific Aortic Valve Disease

Heyde's syndrome is a multisystem disorder describing the association between calcified aortic stenosis, gastrointestinal tract bleeding from arteriovenous malformations, and acquired von Willebrand syndrome. Several studies have reported an increase in prevalence of gastrointestinal arteriovenous malformation in patients with aortic stenosis and vice versa; however, the incidence of Heyde's syndrome remains controversial. In general, the syndrome is prevalent in the elderly population. The pathogenesis and management remain controversial as well. Our review, provides a unique case to highlight the diagnosis and management of Heyde's syndrome while also briefly describing the prevalence, etiology, diagnosis, and management of calcific aortic valve disease in general.

Heyde's Syndrome: Therapeutic Strategies and Long-Term Follow-Up

Fundamentos

A síndrome de Heyde é a associação de estenose aórtica importante com episódio de sangramento gastrointestinal por lesões angiodisplásicas. Pouco é conhecido sobre os fatores associados a novos sangramentos e desfechos em longo prazo. Além disso, a maioria dos dados é restrita a relatos de casos e pequenas séries.

Objetivo

Avaliar o perfil clínico, laboratorial e ecocardiográfico de pacientes com síndrome de Heyde submetidos a intervenção valvar ou tratamento medicamentoso.

Métodos

Coorte prospectiva de 24 pacientes consecutivos entre 2005 e 2018. Foram avaliados dados clínicos, laboratoriais, ecocardiográficos e relacionados à intervenção valvar e a desfechos após o diagnóstico. Valor de p<0,05 foi considerado estatisticamente significante.

Resultados

Metade dos 24 pacientes apresentou sangramento com necessidade de transfusão sanguínea na admissão. Angiodisplasias foram encontradas mais frequentemente no cólon ascendente (62%). Intervenção valvar (cirúrgica ou transcateter) foi realizada em 70,8% dos pacientes, e 29,2% foram mantidos em tratamento clínico. Novos episódios de sangramento ocorreram em 25% dos casos, e não houve diferença entre os grupos clínico e intervenção (28,6 vs. 23,5%, p=1,00; respectivamente). A mortalidade no seguimento de 2 e 5 anos foi de 16% e 25%, sem diferença entre os grupos (log-rank p = 0,185 e 0,737, respectivamente).

Conclusões

Pacientes com síndrome de Heyde tiveram alta taxa de sangramento com necessidade de transfusão sanguínea na admissão, sugerindo ser uma doença grave e com risco elevado de mortalidade. Não encontramos diferenças entre os grupos submetidos ao tratamento clínico e à intervenção valvar em relação a taxas de ressangramento e mortalidade tardia.

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.

Abnormalities in the Von Willebrand-Angiopoietin Axis Contribute to Dysregulated Angiogenesis and Angiodysplasia in Children With a Glenn Circulation

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Children with a bidirectional superior cavopulmonary connection (Glenn circulation) develop dysregulated angiogenesis and pulmonary angiodysplasia in the form of arteriovenous malformations (AVMs). No targeted therapy exists.

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The von Willebrand factor (vWF)–angiopoietin axis plays a major role in normal angiogenesis, angiodysplasia, and AVM formation in multiple diseases.

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vWF and angiopoietin-2 (which destabilizes vessel formation) were abnormal in children with a Glenn circulation versus control children. Within Glenn patients, angiopoietin-1 (which stabilizes vessel formation) and angiogenesis were different in the systemic versus pulmonary circulation. Plasma angiopoietin-1 was lower in the pulmonary circulation of Glenn patients with pulmonary AVMs than Glenn patients without AVMs.

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In parallel, differences in multiple angiogenic and inflammatory signaling peptides were observed between Glenn patients and controls, which indicated derangements in multiple angiogenic pathways in Glenn patients.

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These findings support the novel hypothesis that abnormal vWF metabolism and angiopoietin signaling dysregulate angiogenesis and contribute to pulmonary AVM formation in children with a Glenn circulation.

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The vWF-angiopoietin axis may be a target to correct angiogenic imbalance and reduce pulmonary angiodysplasia in Glenn patients.

Children with a bidirectional superior cavopulmonary (Glenn) circulation develop angiodysplasia and pulmonary arteriovenous malformations (AVMs). The von Willebrand factor (vWF)–angiopoietin axis plays a major role in AVM formation in multiple diseases. We observed derangements in global angiogenic signaling, vWF metabolism, angiopoietins, and in vitro angiogenesis in children with a Glenn circulation versus controls and within Glenn pulmonary versus systemic circulations. These findings support the novel hypothesis that abnormalities in the vWF-angiopoietin axis may dysregulate angiogenesis and contribute to Glenn pulmonary AVMs. The vWF-angiopoietin axis may be a target to correct angiogenic imbalance in Glenn patients, for whom no targeted therapy exists.

Heyde Syndrome: An Unusual Cause of Gastrointestinal Bleeding

Heyde syndrome is a multisystem disorder characterized by the classical triad of aortic stenosis, gastrointestinal (GI) angiodysplasias, and acquired von Willebrand syndrome. GI angiodysplasias, common in older patients, are tortuous, thin-walled blood vessels seen in the mucosa or submucosa of the GI tract and are highly prone to rupture resulting in GI bleeds. In this case report, we describe an elderly female with a past medical history of end-stage renal disease and chronic anemia who presented to the emergency department (ED) with complaints of dark-tarry stools and associated abdominal cramping. Patient reported a history of dark-tarry stools and multiple blood transfusions in the past, secondary to severe anemia. An inpatient echocardiogram was performed, revealing severe aortic stenosis. Additionally, gastroenterology was consulted for esophagogastroduodenoscopy and colonoscopy, which were negative for active bleeding. About a year ago, the patient underwent capsule endoscopy at an outlying facility, which was positive for angiodysplasia. Therefore, due to high clinical suspicion, presence of aortic stenosis, and GI angiodysplasia, a platelet function assay was ordered. It was found to be abnormal, pointing to the presence of acquired von Willebrand syndrome. Hence, a diagnosis of Heyde syndrome was established. The patient gradually improved and was discharged with a follow-up appointment with the cardiologist for a possible transcatheter aortic valve replacement procedure. The patient underwent the procedure without complications, after which she did not report episodes of GI bleeding. In this case report, we discuss the presentation, pathophysiology, diagnostic approach, and management of patients with Heyde syndrome.

Medical Management of Heyde Syndrome

Heyde syndrome is a triad of bleeding colonic angiodysplasia, aortic stenosis, and acquired coagulopathy. It is most commonly seen in the elderly between 60-80 years of age. We present a case of Heyde syndrome presenting with severe anemia secondary to bleeding angiodysplasia or arteriovenous malformations (AVM) in the lower gastrointestinal (GI) tract.

Relationship Between Anemia and Sudden Cardiac Death in Patients With Severe Aortic Stenosis

Aortic stenosis (AS) is associated with significant morbidity and mortality, including sudden cardiac death (SCD). Anemia is a known risk factor for mortality in patients with AS. We sought to understand the prognostic implications between anemia and SCD in severe AS. The Mayo Clinic AS database includes 8,357 adults with severe AS (mean gradient ≥40 mm Hg, aortic valve area ≤1 cm², or peak aortic jet velocity ≥4 m/s) enrolled between January 1, 1995 and April 30, 2015. Survival and cause of death were ascertained from the National Death Index and SCD from medical records. We excluded patients with multiple valvular abnormalities, leaving 7,292 subjects. The median (interquartile range, [IQR]) age was 76 (68, 82) years with 56% male, and median (IQR) hemoglobin level was 12.9 (11.6, 14.1) g/dl. The frequency of anemia (hemoglobin <13.0g/dl for men, <12.0 g/dL for women) was 40%. During median (IQR) follow up of 4.4 (1.8, 8.1) years, 4,056 died (10-year survival 38%) including 225 with SCD (10-year cumulative incidence 5%). In a multivariate model including age, sex, body-mass index, hypertension, diabetes mellitus, myocardial infarction, estimated glomerular filtration rate, and time dependent aortic valve replacement, anemia was associated with increased all-cause mortality (hazard ratios 1.75, 95%CI 1.64, 1.87; p < 0.001) and increased SCD mortality (hazard ratios 1.42, 95%CI 1.07, 1.86; p = 0.01). In conclusions, anemia is a frequent finding in patients with severe AS and independently associated with increased all-cause mortality and SCD. Anemia may be a useful prognostic marker and a modifiable therapeutic target in managing patients with severe AS.

Novel Use of Tamoxifen to Reduce Recurrent Gastrointestinal Bleeding in Patients with Left Ventricular Assist Devices

Gastrointestinal bleeding (GIB) is a frequent complication in patients with continuous-flow left ventricular assist devices (LVAD). We retrospectively evaluated eight patients implanted with a HeartWare LVAD between July 2017 and June 2020 who experienced at least one episode of GIB and were started on tamoxifen 20 mg once daily for secondary prevention. Tamoxifen was associated with a significant decrease in major GIB from a median of 3 (IQR 1.4-7) events/patient-year pre-tamoxifen initiation to 0 (IQR 0-0.9) events/patient-year post-tamoxifen initiation (p = 0.02). Transfusion of packed red blood cells also decreased from 16.8 (IQR 9.9-30.6) units/patient-year pre-tamoxifen initiation to 1.5 (IQR 0-7.5) units/patient-year post-tamoxifen (p = 0.04). Tamoxifen was well tolerated and no thromboembolic complications were observed. This small cohort study suggests that tamoxifen is associated with reduced GIB and transfusion requirements, with no apparent increase in thrombotic risk. A larger, randomized study is warranted to confirm the results of this exploratory analysis. Graphical abstract.

Heyde Syndrome-Pathophysiology and Perioperative Implications

Gastrointestinal (GI) bleeding in patients with calcific aortic valve stenosis (AVS), termed Heyde syndrome, was first described by Edward C. Heyde. The strong association between valvular replacement and the eradication of clinically significant GI bleeding confirmed an underlying pathophysiologic relationship. The rheologic stress created by AVS increases proteolysis of von Willebrand factor (VWF), resulting in loss of predominantly high-molecular-weight VWF (Hmw VWF). Angiodysplastic vessels present in patients with AVS, coupled with the lack of functioning Hmw VWF, increase the risk for GI bleeds. Aortic valve replacement, both surgical and transcatheter-based, is often a definitive treatment for GI bleeding, leading to recovery of Hmw VWF multimers. Perioperative management of patients involves monitoring their coagulation profiles with relevant laboratory tests and instituting appropriate management. Management can be directed in the following two ways: by improving internal release of VWF or by administration of external therapeutics containing VWF. It is important for perioperative physicians to obtain an understanding of the pathophysiology of this disease process and closely monitor the bleeding pattern so that targeted therapies can be initiated.

Small bowel angioectasia as a marker of frailty and poor prognosis

Background and study aims  This study aimed to establish 5-year survival of patients diagnosed with bleeding small bowel (SB) angioectasia, with the hypothesis that many will suffer deaths relating to comorbidity rather than gastrointestinaI bleeding. Patients and methods  SB capsule endoscopy (SBCE) procedures, performed for suspected SB bleeding or iron deficiency anemia, with angioectasia isolated as the cause of SB bleeding and at least 5 years of follow-up data were isolated (n = 125) along with an age-matched group with "normal" SBCE procedures (n = 125). These were retrospectively analysed with further information on mortality and comorbidity gathered through hospital records. Results  Those with angioectasia had a median age of 72.7 years and comorbidities were common. The 5-year survival was 64.0 % (80/125) compared to 70.4 % (88/125) in those with "normal" SBCE. Those with significant cardiac or vascular comorbidity had a poorer survival (52.9 % (37/70) at 5 years) but anticoagulation/antiplatelets/ number of lesions or requirement endoscopic treatment seemed to make little difference. In those with SB bleeding secondary to angioectasia none of the subsequent deaths were directly attributable to gastrointestinal bleeding. Conclusions  In this cohort, SB angioectasia did not lead to any deaths but the 5-year survival was poor due to those diagnosed often being older and having comorbidities. This would support the hypothesis that a diagnosis of SB bleeding secondary to angioectasia suggests frailty.

Heyde Syndrome: A Case Report and Literature Review

Heyde syndrome is characterized by an association between gastrointestinal (GI) bleeding and calcific aortic stenosis (AS). Although the course of disease progression that links AS and GI bleeding has not been determined, overlaps among AS, intestinal dysplasia, and acquired von Willebrand's syndrome are thought to result in GI bleeding. Aortic valve repair in some patients has been reported to result in marked improvement or the complete resolution of signs and symptoms of Heyde syndrome. The prevalence of Heyde syndrome is higher among elderly persons than among other age groups, suggesting that a degenerative process may be a significant factor in the disease progression. This report describes a patient with Heyde syndrome, as well as a review of the current literature. 

Benchtop von Willebrand Factor Testing: Comparison of Commercially Available Ventricular Assist Devices and Evaluation of Variables for a Standardized Test Method

Gastrointestinal bleeding occurs in 20-30% of patients receiving ventricular assist devices (VADs) due, in part, to acquired von Willebrand syndrome. We examined factors to optimize a benchtop method to quantify changes in von Willebrand Factor (VWF) multimer distribution and function in VADs, then applied them to evaluate commercially available devices. Human plasma was circulated through flow loops with VADs. Several experimental conditions were examined, including temperature, viscosity, and enzyme inhibition. Samples were analyzed for VWF collagen-binding activity (VWF:CB) and VWF antigen level. von Willebrand Factor multimer profiles were quantified using gel electrophoresis, near-infrared in-gel visualization, and densitometric analysis. The VWF:CB/antigen ratio in the HeartMate II, CentriMag, and HVAD exhibited average decreases of 46%, 44%, and 36% from baseline after 360 minutes of operation. High molecular weight (hVWF) multimer loss occurred within 30 minutes, although the Levacor and control loop profiles were unchanged. Varying temperature and viscosity altered hVWF degradation rate, but not the final results. Inhibition of a disintegrin and metalloprotease with thrombospondin type 1 repeats, member 13 (ADAMTS13) can potentially distinguish mechanoenzymatic cleavage of VWF from mechanical degradation. We developed a repeatable benchtop method to evaluate VWF compatibility of VADs similar to hemolysis testing that can be adopted for preclinical VAD evaluation.

Pre-procedural abnormal function of von Willebrand Factor is predictive of bleeding after surgical but not transcatheter aortic valve replacement

Both transcatheter aortic valve implantation (TAVI) and surgical aortic valve replacement (SAVR) have been proven to effectively correct von Willebrand Factor (vWF) pathologies, however there is limited data simultaneously comparing outcomes of both approaches. We prospectively enrolled patients with severe aortic stenosis referred for TAVI (n = 52) or SAVR (n = 48). In each case, vWF antigen (vWF:Ag), vWF activity (vWF:Ac) and activity-to-antigen (vWF:Ac/Ag) ratio were assessed at baseline, 24 h and 72 h after procedure. VWF abnormalities were defined as reduced vWF:Ac/Ag ratio (< 0.8). Bleeding events in both arms were classified according to Valve Academic Research Consortium (VARC-2) definitions. Overall, there was no difference between patients referred for TAVI and SAVR in vWF:Ac (1.62 ± 0.52 vs 1.71 ± 0.64; p = 0.593), vWF:Ag (1.99 ± 0.81 vs 2.04 ± 0.81; p = 0.942) or vWF:Ac/Ag ratio (0.84 ± 0.16 vs 0.85 ± 0.12; p = 0.950). Pathological vWF:Ac/Ag ratio was found in 20 (38%) TAVI and 15 (31%) SAVR patients (p = 0.407). Normalization of vWF:Ac/Ag ratio at day 3 after procedure was achieved in 19 (95%) TAVI and 13 (87%) SAVR patients (p = 0.439). Similar prevalence of major or life-threatening bleedings (MLTB) after TAVI and SAVR in entire groups was observed (19% vs. 23%, p = 0.652). VWF abnormalities were associated with higher incidence of MLTB in SAVR (53% vs 9%, p < 0.001), but not TAVI (15% vs. 22%, p = 0.132). Accordingly, in receiver-operating characteristic curve analysis vWF:Ac/Ag ratio < 0.8 showed significant sensitivity and specificity for predicting MLTB in SAVR group (AUC 0.735, 95% CI 0.538–0.931, p = 0.019). We proved that abnormal function of vWF is corrected successfully after both TAVI and SAVR, but vWF abnormalities are predictive of MLTB only in surgical patients.

von Willebrand Factor and Management of Heart Valve Disease: JACC Review Topic of the Week

For decades, numerous observations have shown an intimate relationship between von Willebrand factor (VWF) multimer profile and heart valve diseases (HVD). The current knowledge of the unique biophysical properties of VWF helps us to understand the longstanding observations concerning the bleeding complications in patients with severe HVD. Not only does the analysis of the VWF multimer profile provide an excellent evaluation of HVD severity, it is also a strong predictor of clinical events. Also of importance, VWF responds within minutes to any significant change in hemodynamic valve status, making it an accurate marker of the quality of surgical and transcatheter therapeutic interventions. The authors provide in this review a practical, comprehensive, and evidence-based framework of the concept of VWF as a biomarker in HVD, advocating for its implementation into the clinical decision-making process besides usual clinical and imaging evaluation. They also delineate critical knowledge gaps and research priorities to definitely validate this concept.

Clinical and In Vitro Evidence That Left Ventricular Assist Device-Induced von Willebrand Factor Degradation Alters Angiogenesis

Background Gastrointestinal bleeding from angiodysplasia is a major problem in continuous-flow left ventricular assist device (LVAD) patients. LVAD shear stress causes pathologic degradation of VWF (von Willebrand factor). A mechanistic relationship between VWF degradation and angiodysplasia has not been explored. We tested 2 novel hypotheses: (1) clinical hypothesis: VWF fragments are elevated in LVAD patients that develop angiodysplasia and (2) in vitro hypothesis: VWF fragments generated during LVAD support alter angiogenesis, which may contribute to angiodysplasia. Methods and Results Clinical study: Paired blood samples were collected from continuous-flow LVAD patients (n=35). VWF was quantified with immunoblotting. In vitro experiments: (1) To investigate whether LVAD support alters angiogenesis, human endothelial cells were cultured with LVAD patient plasma (n=11). To investigate mechanism, endothelial cells were cultured with VWF fragments produced by exposing human VWF and ADAMTS-13 (VWF protease) to LVAD-like shear stress (175 dyne/cm², n=8). Clinical study results: in all patients (n=35, mean support 666±430 days), LVAD support degraded high-molecular-weight VWF multimers ( P<0.0001) into low-molecular-weight VWF multimers ( P<0.0001) and VWF fragments ( P<0.0001). In patients with gastrointestinal bleeding from angiodysplasia (n=7), VWF fragments were elevated ( P=0.02) versus nonbleeders. In contrast, in patients with gastrointestinal bleeding without angiodysplasia, VWF fragments were not elevated versus nonbleeders ( P=0.96). In vitro experiments results: LVAD patient plasma caused abnormal angiogenesis with reduced tubule length ( P=0.04) and migration ( P=0.05). Similarly, endothelial cells grown with VWF degradation fragments exhibited reduced tubule length ( P<0.001) and migration ( P=0.01). Conclusions LVAD patients who bled from angiodysplasia had higher levels of VWF fragments than nonbleeders and gastrointestinal bleeders without angiodysplasia. VWF fragments caused abnormal angiogenesis in vitro. These findings suggest that VWF fragments may be a mechanistic link between LVAD support, abnormal angiogenesis, angiodysplasia, and gastrointestinal bleeding.

Functional capillary impairment in patients with ventricular assist devices

The implantation of continuous – flow ventricular assist devices (VAD) is suggested to evoke angiodysplasia contributing to adverse events such as gastrointestinal bleeding. We evaluated in vivo capillary density and glycocalyx dimensions to investigate possible systemic microvascular changes in patients with chronic heart failure and VAD support vs. standard medical treatment. Forty-two patients with VAD support were compared to forty-one patients with ischemic and non-ischemic chronic heart failure (CHF) on standard pharmacotherapy and to a group of forty-two healthy subjects in a prospective cross-sectional study. Sublingual microcirculation was visualized using Sidestream Darkfield videomicroscopy and functional and perfused total capillary densities were quantified. Patients with VAD implantation were followed for one year and bleeding events were recorded. Median time after VAD implantation was 18 months. Patients were treated with centrifugal-flow devices (n = 31) or axial-flow devices (n = 11). Median functional capillary density was significantly lower in patients with VAD therapy as compared to CHF patients (196 vs. 255/mm², p = 0.042, adjusted p-value). Functional and total capillary densities were 44% and 53% lower (both p < 0.001) in patients with VAD therapy when compared to healthy subjects. Cox regression analysis revealed loss of capillary density as a significant predictor of bleeding events during one -year follow-up of VAD patients (HR: 0.987, CI (95%): 0.977–0.998, p = 0.021 for functional and 0.992, CI (95%): 0.985–0.999, p = 0.03 for total capillary density). In conclusion, patients with VAD support exhibit capillary density rarefaction, which was associated with bleeding events. If confirmed independently, capillary impairment may be evaluated as novel marker of bleeding risk.

Gastrointestinal Bleeding in Left Ventricular Assist Device: Octreotide and Other Treatment Modalities

Left ventricular assist devices (LVADs) offer a therapeutic strategy for patients with end-stage heart failure. Increased device utilization has also increased the incidence of device-related complications including gastrointestinal bleeding (GIB). Multiple mechanisms have been proposed in the pathophysiology of continuous-flow LVAD-associated GIB including physiologic changes associated with high shear and nonpulsatile flow such as gastrointestinal arteriovenous malformations and acquired von Willebrand syndrome. Strategies to minimize the morbidity and mortality of LVAD-associated GIB are needed. Octreotide, a somatostatin analogue, has been described as an adjunct to current therapies and interventions. Factors that contribute to LVAD-associated GIB may be targeted by the pharmacologic effects of octreotide, including improved platelet aggregation, increased vascular resistance, and decreased splanchnic circulation. Octreotide has demonstrated clinical benefit in several case series and clinical trials for the treatment of LVAD-associated GIB. The focus of this article will be to review the pathophysiology of LVAD-associated GIB, discuss pharmacologic and nonpharmacologic treatment modalities, and review available literature on the role of octreotide in the management of LVAD-associated GIB.

Early timing of single balloon enteroscopy is associated with increased diagnostic yield in patients with overt small bowel bleeding

BACKGROUND/PURPOSE

Although performing balloon enteroscopy soon after the onset of small bowel bleeding appeared to enhance diagnostic rate, the optimal timing was unclear.

METHODS

A retrospective cohort study in a single referral center. Patients with overt, suspected small bowel bleeding who underwent primary single-balloon enteroscopy (SBE) were evaluated to determine the association between procedure timing and diagnostic yield rates.

RESULTS

A total of 220 patients were enrolled (47.7% males; mean age, 65.6 ± 18.1 years). They were stratified into four groups based on the timing of SBE: emergency (<24 h after onset or continued bleeding, n = 64), 24-72 h (n = 28), 3-7 days (n = 41), and >7 days (n = 87). A significant trend of decreasing diagnostic yields was observed across the groups (90.6%, 67.9%, 68.3%, and 44.8%, respectively, P < 0.0001). Diagnostic yield rates were different between emergency and 24-72 h groups (P < 0.0001), and between 3 and 7 days and >7 days groups (P < 0.05), but not between 24 and 72 h and 3-7 days groups (P = 0.97). In multivariate regression analysis, emergency, ≤ 3 days, and ≤7 days SBEs had greater yield rates than SBEs at later timings.

CONCLUSION

The likelihood of diagnostic yield was highest when SBE was performed during continued bleeding or within 24 h of onset, and gradually declined as waiting time increased. We therefore recommend that SBE should be performed as soon as possible, preferably no later than seven days.

Comparison of Frequency of Late Gastrointestinal Bleeding With Transcatheter Versus Surgical Aortic Valve Replacement

Improvements in technology and operator experience have led to exponential growth of transcatheter aortic valve implantation (TAVI) programs. Late bleeding complications were recently highlighted after TAVI with a high impact on morbidity. The purpose of the present study was to assess the incidence and financial impact of late Gastrointestinal (GI) bleeding after TAVI, and compare with the surgical cohort. Retrospective analysis of the National Readmissions Database was performed from January 2011 to December 2014, and patients who underwent TAVI or surgical aortic valve replacement (SAVR) were identified. Incidence of readmission with a diagnosis of GI bleeding was utilized as the primary end point. Overall, 43,357 patients were identified who underwent TAVI, whereas 310,013 patients underwent SAVR. Compared with SAVR, TAVI patients were older (81 vs 68y, p < 0.001), more women (48% vs 36%, p < 0.001), and had higher Elixhauser Comorbidity Index (6 vs 5, p < 0.001). Hospital stay was shorter with TAVI (5 vs 8 days, p < 0.001), but raw in-hospital mortality rates were similar (4.2% vs 3.8%, p = 0.022). In the TAVI cohort, 3.3% of patients were rehospitalized for GI bleeding compared with 1.5% of the SAVR cohort (p < 0.001). Average time to bleeding readmission was similar between cohorts (92 vs 84 days, p = 0.049). After multivariable adjustment, TAVI remained significantly associated with readmissions for GI bleeding compared with SAVR Adjusted Odds Ratio (AOR 1.54 [1.38 to 1.71], p < 0.001). In this national cohort study, TAVI was associated with more frequent readmissions for late GI bleeding compared with SAVR. In conclusion, strategies to reduce late GI bleeding may serve as important targets for improvement in overall quality of care.

An overview of angiodysplasia: management and patient prospects

Gastrointestinal angiodysplasias (GIADs) have a wide variety of presentations, which can be significant and debilitating in a subset of patients. Endoscopic ablation is currently the most effective treatment for GIADs, however re-bleeding rates are high. Several medical have been used for GIADs and reported in the literature, however these medications have significant side effect profiles and randomized controlled trials are lacking. A relatively poor understanding of the pathophysiology of GIAD formation has limited the development of more effective treatments and improved diagnostic and prognostic markers for GIAD. However, recent advances in research in the area of angiogenesis have identified a potential role for certain angiogenic factors including Angiopoeitin 1 and 2, in the pathophysiology of GIAD. Areas covered: We performed an extensive pubmed search of all articles mentioning GIAD and summarized our findings focussing on patient management and prospects. We summarize the available literature regarding the medical, endoscopic, and radiological management of GIAD and the value of clinical prognostic factors. Expert commentary: Although the area of angiogenesis is a novel area of research in GIAD, it represents an exciting avenue for development with the potential to improve diagnostic and prognostic tools to improve patient outcome.

Circulatory Mechanotherapeutics: Moving with the Force

PURPOSE OF REVIEW

This review describes the current state of advancements in mechanical circulatory support (MCS) devices with significantly improved hemodynamic performance and decreased adverse events. Novel considerations for future MCS designs that impart spiral flow regimes will be detailed.

RECENT FINDINGS

Significant challenges in MCS device use have included size reduction, premature pump mechanical bearing failure, acquired bleeding disorders, and vascular complications related to high shear forces and jetting. Some of these problems have been improved upon, such as the use of magnetically levitated impellers and hydrodynamic bearings. The relative simplicity of continuous flow pumps has also enabled their miniaturization, portability, and reduced energy consumption. Recent studies by our group demonstrated that spiral forms of flow possess hemodynamically beneficial attributes at the MCS outflow cannula and aorta interface, reducing jet impact, organizing streamlines, and thereby improving endothelial function through wall shear stress modulation. Despite MCS design improvements, they are far from perfect. Induced spiral fluid modulation may help address the known flow-mediated disturbances in vascular mechanobiology.

Von Willebrand factor and the aortic valve: Concepts that are important in the transcatheter aortic valve replacement era

Since the approval of the first transcatheter aortic valve replacement (TAVR) device in 2011, this technology has undergone substantial enhancements and exponential growth. However, valve thrombosis and residual paravalvular leaks (PVL) are among the challenges that require further investigation. Recently, monitoring von Willebrand factor (vWF) multimers has emerged as a tool to help evaluate the severity of PVL after TAVR. Following TAVR, vWF large multimers recovery have been documented. The role of large vWF multimers recovery and their interactions with platelets, and the endothelium have not been entirely elucidated. In this review, we discuss vWF synthesis and its role in aortic stenosis. We further provide an overview of the studies that investigated changes affecting vWF multimers following TAVR and the role of HMW vWF multimers monitoring in the determination of PVL severity. We also offer potential future directions for what will be fertile ground for research in this field.

Aortic stenosis and anemia with an update on approaches to managing angiodysplasia in 2018

Angiodyplasia and aortic stenosis are both conditions that are highly prevalent in elderly people and can often co-exist. Recent studies suggest that this association is related to subtle alterations in plasma coagulation factors. The von Willebrand factor is the strongest link between aortic stenosis and bleeding associated with gastrointestinal angiodysplasia. With an ageing population, the disease burden of aortic stenosis and its association with angiodysplasia of the bowel makes this an incredibly underdiagnosed yet important condition. Clinicians should be aware of this association when dealing with elderly patients presenting either with unexplained anemia, gastrointestinal bleeding or with aortic stenosis. A high index of suspicion and appropriate diagnostic techniques followed by appropriate and prompt treatment could be life-saving. No clear guidelines exist on management but surgical aortic valve replacement is thought to offer the best hope for long-term resolution of bleeding. With a growing number of technological armamentarium in the management of such patients, especially with the advent of transcatheter aortic valve implantation, new options can be offered even to elderly patients with comorbidities for whom conventional surgery would have been impossible.

von Willebrand factor regulation of blood vessel formation

Several important physiological processes, from permeability to inflammation to hemostasis, take place at the vessel wall and are regulated by endothelial cells (ECs). Thus, proteins that have been identified as regulators of one process are increasingly found to be involved in other vascular functions. Such is the case for von Willebrand factor (VWF), a large glycoprotein best known for its critical role in hemostasis. In vitro and in vivo studies have shown that lack of VWF causes enhanced vascularization, both constitutively and following ischemia. This evidence is supported by studies on blood outgrowth EC (BOEC) from patients with lack of VWF synthesis (type 3 von Willebrand disease [VWD]). The molecular pathways are likely to involve VWF binding partners, such as integrin αvβ3, and components of Weibel-Palade bodies, such as angiopoietin-2 and galectin-3, whose storage is regulated by VWF; these converge on the master regulator of angiogenesis and endothelial homeostasis, vascular endothelial growth factor signaling. Recent studies suggest that the roles of VWF may be tissue specific. The ability of VWF to regulate angiogenesis has clinical implications for a subset of VWD patients with severe, intractable gastrointestinal bleeding resulting from vascular malformations. In this article, we review the evidence showing that VWF is involved in blood vessel formation, discuss the role of VWF high-molecular-weight multimers in regulating angiogenesis, and review the value of studies on BOEC in developing a precision medicine approach to validate novel treatments for angiodysplasia in congenital VWD and acquired von Willebrand syndrome.

A case of recurrent obscure gastrointestinal bleeding: Heyde's syndrome - case report and review

Gastrointestinal bleeding from angiodysplasias in patients with aortic stenosis is termed as 'Heyde's syndrome'. We report a case of Heyde's syndrome successfully treated with trans-catheter aortic valve replacement.

Microvasculature-on-a-chip for the long-term study of endothelial barrier dysfunction and microvascular obstruction in disease

Alterations in the mechanical properties of erythrocytes occurring in inflammatory and hematologic disorders such as sickle cell disease (SCD) and malaria often lead to increased endothelial permeability, haemolysis, and microvascular obstruction. However, the associations among these pathological phenomena remain unknown. Here, we report a perfusable, endothelialized microvasculature-on-a-chip featuring an interpenetrating-polymer-network hydrogel that recapitulates the stiffness of blood-vessel intima, basement membrane self-deposition and self-healing endothelial barrier function for longer than 1 month. The microsystem enables the real-time visualization, with high spatiotemporal resolution, of microvascular obstruction and endothelial permeability under physiological flow conditions. We found how extracellular heme, a hemolytic byproduct, induces delayed but reversible endothelial permeability in a dose-dependent manner, and demonstrate that endothelial interactions with SCD or malaria-infected erythrocytes cause reversible microchannel occlusion and increased in situ endothelial permeability. The microvasculature-on-a-chip enables mechanistic insight into the endothelial barrier dysfunction associated with SCD, malaria and other inflammatory and haematological diseases.

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.