Gastrointestinal bleeding from arteriovenous malformations in patients supported by the Jarvik 2000 axial-flow left ventricular assist device

Pre- and Post-Implant Endoscopy in Left Ventricular Assist Device Recipients: A Single-Center Experience

Background

Gastrointestinal bleeding (GIB) is common in left ventricular assist devices (LVADs) patients, but the optimal screening approach before LVAD implantation is still unclear. The aim of the study was to describe our experience with pre- and post-LVAD implantation endoscopic screening and subsequent GI bleeding in this cohort.

Methods

A retrospective review was conducted among all patients who underwent LVAD implantation at Saint Luke's Hospital, between 2010 and 2020. The data were reviewed to determine the yield and safety of endoscopic procedures performed within 1 month before LVAD placement and the incidence of GIB within 1 year after implantation.

Results

A total of 167 LVAD patients met the inclusion criteria, and 23 underwent pre-implantation endoscopic evaluation. Angiodysplasia had a significantly higher odds ratio (OR) of 9.41 (95% confidence interval (CI): 2.01 - 44.09) in post-LVAD endoscopy, while there was no significant difference in bleeding from other sources such as peptic ulcer disease or diverticular bleeding. There was no difference in the incidence of GIB in patients who underwent endoscopic evaluation pre-LVAD compared to post-LVAD GIB (32.6% vs. 39.1%, P = 0.64). Endoscopy was well-tolerated in this cohort, and argon plasma coagulation was the most commonly used intervention to achieve hemostasis.

Conclusions

According to our results, we recommend against routine pre-LVAD endoscopic screening. Instead, we suggest an individualized approach, where decisions are made on a case-by-case basis.

Partial Pressure of End-Tidal Oxygen and Blood Lactate During Cardiopulmonary Exercise Testing in Healthy Older Participants and Patients at Risk of Cardiac Disease

Background

The partial pressure of end-tidal oxygen (PETO2) and end-tidal oxygen concentration (ETO2) are among the indices that can be measured by exhaled gas analysis. Several observational studies have shown that skeletal muscle function is impaired in patients with cardiac disease; thus, the assessment of skeletal muscle function is important. Additionally, although it has recently been suggested that the difference in PETO2 from rest to the ventilatory anaerobic threshold (VAT) reflects oxygen availability in peripheral factors, primarily skeletal muscle, the evidence for this is not well established. Therefore, we hypothesized and investigated whether increased blood lactate (BLa) levels, resulting from decreased skeletal muscle and mitochondrial oxygen availability, and PETO2 dynamics during cardiopulmonary exercise testing (CPET) would be related.

Methods

All participants performed the symptomatic limited CPET, and their BLa levels were measured. The difference in PETO2 and ETO2 from rest to VAT determined by the V-slope method (ΔPETO2 and ΔETO2) was calculated and compared with the increase in BLa due to exercise testing.

Results

We recruited 22 healthy older participants (nine males; 69.4 ± 6.8 years) and 11 patients with cardiovascular risk (eight males; 73.0 ± 8.8 years). ΔPETO2 and ΔETO2 did not differ between the two groups (P = 0.355 and P = 0.369, respectively), showing no correlation between increase in BLa from rest to VAT, but were significantly correlated with an increase in BLa from rest to the end of exercise (ΔPETO2, P = 0.030; ΔETO2, P = 0.029). The correlation was particularly pronounced among those at cardiovascular risk (ΔPETO2, P = 0.012; ΔETO2, P = 0.011).

Conclusions

ΔPETO2 and ΔETO2 from rest to VAT during CPET may be useful as indices reflecting skeletal muscle oxygen utilization capacity.

Gastrointestinal bleeding and pro-angiogenic shift in the angiopoietin axis with continuous flow left ventricular assist device implantation

BACKGROUND

Gastrointestinal bleeding (GIB) affects up to 40% of continuous-flow left ventricular assist device (CF-LVAD) recipients. A higher risk of GIB is seen in CF-LVAD recipients with lower device pulsatility without a known mechanism. One hypothesis is that the novel hemodynamics in CF-LVAD recipients affect angiogenesis signaling. We aimed to (1) measure serum levels of angiopoietin (Ang)-1, Ang-2, and VEGF-A in CF-LVAD recipients with and without GIB and in healthy controls and (2) evaluate correlations of those levels with hemodynamics.

METHODS

We recruited 12 patients with CF-LVADs (six who developed GIB after device implantation) along with 12 age-matched controls without heart failure or GIB and measured Ang-1, Ang-2, and VEGF-A levels in serum samples from each patient.

RESULTS

CF-LVAD recipients had significantly higher Ang-2 and lower Ang-1 levels compared to controls with no difference in VEGF-A levels. CF-LVAD recipients with GIB had lower Ang-1 levels than those without GIB. There were trends for pulse pressure to be positively correlated with Ang-1 levels and negatively correlated with Ang-2 levels in CF-LVAD recipients with no correlation observed in healthy controls.

CONCLUSION

CF-LVAD recipients demonstrated a shift toward a pro-angiogenic phenotype in the angiopoietin axis that is significantly associated with GIB and may be linked to low pulse pressure.

Role of octreotide in small bowel bleeding

Gastrointestinal bleeding accounts for a drastic negative impact on the quality of the patients’ lives as it requires multiple diagnostic and therapeutic interventions to identify the source of the bleeding. Small bowel bleeding is the least common cause of gastrointestinal bleeding. However, it is responsible for the majority of complaints from patients with persisting or recurring bleeding where the primary source of bleeding cannot be identified despite investigation. A somatostatin analog known as octreotide is among the medical treatment modalities currently used to manage small bowel bleeding. This medication helps control symptoms of gastrointestinal bleeding by augmenting platelet aggregation, decreasing splanchnic blood flow, and antagonizing angiogenesis. In this review article, we will highlight the clinical efficacy of octreotide in small bowel bleeding and its subsequent effect on morbidity and mortality.

Pathophysiology and therapeutic management of anemia in gastrointestinal disorders

INTRODUCTION

Anemia is a common complication of gastrointestinal (GI) disorders, with a prevalence up to 60% in celiac disease (CeD) and inflammatory bowel disease (IBD). Iron deficiency anemia (IDA) is the most prevalent form of anemia in these conditions, but chronic inflammation and vitamin B12 deficiency represent other common contributing mechanisms, especially in IBD.

AREAS COVERED

We discuss the pathogenesis of anemia in various medical GI disorders, the sometime problematic distinction between IDA, anemia of inflammation (AI) and the association of the two, and therapeutic and preventive measures that can be useful for the management of anemia in GI disorders. Unfortunately, with the exception of IDA and AI in IBD, large RCT concerning the treatment of anemia in GI disorders are lacking.

EXPERT OPINION

Anemia management strategies in GI disorders are outlined, with a focus on the main prevention, diagnostic, and therapeutic measures. Specific problems and situations such as the role of gluten-free diet for IDA treatment in CeD, the choice between oral and parenteral supplementation of iron or vitamin B12 in carential anemias, the use of endoscopic procedures to stop bleeding in intestinal angiodysplasia and preventive/treatment strategies for NSAID-associated GI bleeding are discussed.

Continuous-Flow Left Ventricular Assist Device Support in Patients with Ischemic Versus Nonischemic Cardiomyopathy

To determine whether the cause of cardiomyopathy affects outcomes in patients who undergo continuous-flow left ventricular assist device support, we compared postimplant adverse events and survival between patients with ischemic and nonischemic cardiomyopathy. The inclusion criteria for the ischemic group were a history of myocardial infarction or revascularization (coronary artery bypass grafting or percutaneous coronary intervention), ≥75% stenosis of the left main or proximal left anterior descending coronary artery, or ≥75% stenosis of ≥2 epicardial vessels. From November 2003 through March 2016, 526 patients underwent device support: 256 (48.7%) in the ischemic group and 270 (51.3%) in the nonischemic group. The ischemic group was older (60.0 vs 50.0 yr), included more men than women (84.0% vs 72.6%), and had more comorbidities. More patients in the nonischemic group were able to have their devices explanted after left ventricular recovery (5.9% vs 2.0%; P=0.02). More patients in the ischemic group had gastrointestinal bleeding (31.2% vs 22.6%; P=0.03), particularly from arteriovenous malformations (20.7% vs 11.9%; P=0.006) and ulcers (16.4% vs 9.3%; P=0.01). Kaplan-Meier analysis revealed no difference in overall survival between groups (P=0.24). Older age, previous sternotomy, higher total bilirubin level, and concomitant procedures during device implantation independently predicted death (P ≤0.03), whereas cause of heart failure did not (P=0.08). Despite the similarity in overall survival between groups, ischemic cardiomyopathy was associated with more frequent gastrointestinal bleeding. This information may help guide the care of patients with ischemic cardiomyopathy who receive continuous-flow left ventricular assist device support.

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.

Regulation of Angiopoietin-2 Before and After Mechanical Circulatory Support Therapy

Gastrointestinal bleeding (GIB) during mechanical circulatory support (MCS) is a major unsolved comorbidity. Inadequate activation of angiopoietin-2-related systems is considered as a major cause of GIB. However, the regulation of angiopoietin-2 remains unknown. Consecutive 20 patients who received continuous-flow MCS therapy (MCS group) and 12 with advanced heart failure (HF; HF group) were prospectively enrolled and their angiopoetin-2 levels were compared. Angiopoietin-2 level had a moderate correlation with log10 B-type natriuretic peptide (BNP; r = 0.39, p < 0.001). The MCS group had significantly higher angiopoietin-2 level divided by log10 BNP compared with the HF group (2.80 ± 0.20 vs. 1.88 ± 0.17, p < 0.001). Angiopoetin-2 had a moderate correlation with central venous pressure and C-reactive protein during the MCS support (r = 0.51 and r = 0.45, respectively). Higher angiopoietin-2 level divided by log10 BNP (> 4.3) was significantly associated with the occurrence of GIB with a hazard ratio of 296 (95% confidence interval 2.24-38620, p = 0.0224). Angiopoietin-2 was already elevated in the HF cohort and more elevated following MCS initiation. Among the MCS cohort, angiopoietin-2 was particularly elevated in patients with systemic congestion and inflammation and was associated with higher incidence of GIB.

Contemporary outcomes of continuous-flow left ventricular assist devices-a systematic review

Background

End stage heart failure is a major cause of morbidity and mortality, and its prevalence is expected to rise with the ageing population. For suitable patients, orthotopic heart transplantation remains the gold standard therapy, however, a paucity of donor organs has led to the development of left ventricular assist devices (LVAD). These devices can be utilized as either a bridge-to-transplant (BTT) or as an alternative to heart transplantation. While these devices can prolong life and improve quality of life, they are associated with a significant number of adverse events. We aim to systematically review the literature to quantify survival and the incidence of adverse events following implantation of continuous-flow LVADs (cf-LVAD).

Methods

A systematic review was performed to determine outcomes following implantation of a cf-LVAD. Primary outcomes were survival and frequency of adverse events (such as bleeding, infection, thrombosis, stroke and right ventricular failure). Secondary outcomes included quality of life and assessment of functional status.

Results

Sixty-three studies reported clinical outcomes of 9,280 patients. Survival after cf-LVAD varied between studies. Industry-funded trials generally reported better overall survival than the single- and multi-center case series, which showed significant variation. The largest registry report documented twelve, twenty-four and forty-eight-month survival rates of 82%, 72% and 57% respectively. The most commonly reported adverse events were gastrointestinal bleeding (GIB), device-related infection, neurological events and right heart failure (RHF). Bleeding, RHF and infection were the most frequent complications experienced by those supported with cf-LVAD, occurring in up to 35%, 40% and 55% of patients, respectively. Quality of life as measured using the Kansas City Cardiomyopathy Questionnaire (KCCQ) and functional status as measured with the 6-minute walk test (6MWT) improved after cf-LVAD implantation with no decline evident two years after implantation.

Conclusions

The paucity of donor hearts has led to the development of left-ventricular assist devices as a BTT or as a destination therapy (DT). Outcomes after cf-LVAD implantation are excellent, with short-term survival comparable to heart transplantation, but long-term survival remains limited due to the incidence of post-implantation adverse events. Despite these complications, quality of life and functional status improve significantly post-implantation and remain improved over the long-term. This study demonstrates the potential benefits of cf-LVAD therapy whilst also identifying adverse events as an area of increased morbidity and mortality.

Device-Induced Hemostatic Disorders in Mechanically Assisted Circulation

Mechanically assisted circulation (MAC) sustains the blood circulation in the body of a patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) or on ventricular assistance with a ventricular assist device (VAD) or on extracorporeal membrane oxygenation (ECMO) with a pump-oxygenator system. While MAC provides short-term (days to weeks) support and long-term (months to years) for the heart and/or lungs, the blood is inevitably exposed to non-physiological shear stress (NPSS) due to mechanical pumping action and in contact with artificial surfaces. NPSS is well known to cause blood damage and functional alterations of blood cells. In this review, we discussed shear-induced platelet adhesion, platelet aggregation, platelet receptor shedding, and platelet apoptosis, shear-induced acquired von Willebrand syndrome (AVWS), shear-induced hemolysis and microparticle formation during MAC. These alterations are associated with perioperative bleeding and thrombotic events, morbidity and mortality, and quality of life in MCS patients. Understanding the mechanism of shear-induce hemostatic disorders will help us develop low-shear-stress devices and select more effective treatments for better clinical outcomes.

The Role of a Disintegrin and Metalloproteinase Proteolysis and Mechanical Damage in Nonphysiological Shear Stress-Induced Platelet Receptor Shedding

In order to explore the role of a disintegrin and metalloproteinase (ADAM) proteolysis and direct mechanical damage in non-physiologic shear stress (NPSS)-caused platelet receptor shedding, the healthy donor blood treated with/without ADAM inhibitor was exposed to NPSS (150 Pa). The expression of the platelet surface receptors glycoprotein (GP) Ibα and glycoprotein (GP) VI (GPVI) in NPSS-damaged blood was quantified with flow cytometry. The impact of ADAM inhibition on adhesion of NPSS-damaged platelets on von Willibrand factor (VWF) and collagen was explored with fluorescence microscopy. The impact of ADAM inhibition on ristocetin- and collagen-caused aggregation of NPSS-damaged platelets was examined by aggregometry. The results showed that ADAM inhibition could lessen the NPSS-induced loss of platelet surface receptor GPIbα (12%) and GPVI (9%), moderately preserve adhesion of platelets on VWF (7.4%) and collagen (8.4%), and partially restore the aggregation of NPSS-sheared platelets induced by ristocetin (18.6 AU*min) and collagen (48.2 AU*min). These results indicated that ADAM proteolysis played a role in NPSS-induced receptor shedding. However, the ADAM inhibition couldn't completely suppress the NPSS-caused loss of the platelet surface receptors (GPIbα and GPVI), only partially prevented the NPSS-induced reduction of platelet adhesion to VWF and collagen, and the agonist (ristocetin and collagen)-caused platelet aggregation. These results suggested that the direct mechanical damage is partially responsible for NPSS-induced receptor shedding in addition to the ADAM proteolysis. In conclusion, NPSS relevant to blood contacting medical devices can induce ADAM proteolysis and direct mechanical damage on the platelet receptor GPIbα and GPVI, leading to comprised hemostasis.

Decreased RPM reduces von Willebrand factor degradation with the EVAHEART LVAS: implications for device-specific LVAD management

BACKGROUND

Continuous-flow left ventricular assist devices (LVADs) produces supraphysiologic shear stress that causes von Willebrand factor (VWF) degradation and a bleeding diathesis. Reduction of revolutions per minute (RPM) with axial-flow LVADs does not decrease shear stress enough to reduce VWF degradation and bleeding. However, it is unknown if RPM reduction with centrifugal flow LVADs may minimize VWF degradation. We tested the hypothesis that RPM reduction preserves VWF multimers in the centrifugal-flow EVAHEART left ventricular assist system (LVAS), which is designed to minimize shear stress and blood trauma.

METHODS

Whole blood samples were collected from humans (n = 28). Blood was circulated in ex vivo mock circulatory loops for 6 hours with an EVAHEART LVAS at 2300 (n = 12), 2100 (n = 8), or 1800 RPM (n = 8). Immunoblotting was used to resolve and quantify VWF multimers and degradation fragments.

RESULTS

RPM reduction from 2300 to 2100 to 1800 RPM significantly decreased EVAHEART blood flow from 5.8 ± 0.4 to 4.3 ± 0.6 to 4.1 ± 0.5 L/min (analysis of variance [ANOVA], P = .03). RPM reduction protected VWF from pathologic degradation. At lower RPMs, significantly greater levels of VWF multimers were observed (ANOVA, P = .001). Similarly, at lower RPMs, significantly fewer VWF fragments, a product of VWF degradation, were observed (ANOVA, P = .007).

CONCLUSIONS

RPM reduction significantly reduced VWF degradation with the centrifugal-flow EVAHEART LVAS, an LVAD specifically designed with low shear stress. Different LVADs have unique hematologic footprints and should be managed with device-specific protocols. Adjustment of RPM to minimize blood trauma while still maintaining physiologic hemodynamics has the potential to decrease complications related to LVAD-associated von Willebrand's disease, such as gastrointestinal bleeding and hemorrhagic stroke.

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.

Sudden Cardiac Arrest Survivorship: A Scientific Statement From the American Heart Association

Cardiac arrest systems of care are successfully coordinating community, emergency medical services, and hospital efforts to improve the process of care for patients who have had a cardiac arrest. As a result, the number of people surviving sudden cardiac arrest is increasing. However, physical, cognitive, and emotional effects of surviving cardiac arrest may linger for months or years. Systematic recommendations stop short of addressing partnerships needed to care for patients and caregivers after medical stabilization. This document expands the cardiac arrest resuscitation system of care to include patients, caregivers, and rehabilitative healthcare partnerships, which are central to cardiac arrest survivorship.

Use of Ventricular Assist Devices and Heart Transplantation for Advanced Heart Failure

There are only 2 treatments for the thousands of patients who progress to the most advanced form of heart failure despite the application of guideline-based medical therapy, use of ventricular assist devices and heart transplantation. There has been a great deal of progress in both of these therapies that have led to improved outcomes including significant improvement in survival and functional capacity. Heart transplantation offers the best short- and long-term survival for patients with end-stage heart failure, and the majority of these recipients achieve relatively limitless functional capacity for their age. However, the chronic shortage of available donors limits the number of recipients in the United States to an only 2500 patients/y or only a fraction of potential candidates. The significant improvement in outcomes now possible with durable ventricular assist devices has led to a significant increase in their use, which now exceeds the volume of heart transplants in the United States, with the greatest growth in use for those not considered to be candidates for heart transplantation, previously referred to as destination therapy. This article will review the substantial progress that has taken place for both of these life-saving treatment options, as well as the future directions.

Outcomes of gastrointestinal bleeding in patients with left ventricular assist devices: a tertiary care experience

Background and study aims  Left ventricular assist device (LVAD) placement is a therapeutic modality for patients with end-stage heart failure. Gastrointestinal bleeding is a common complication following LVAD implantation. The aim of this study was to report our experience in management and outcomes of gastrointestinal bleeding in a large cohort of patients with LVADs. Patients and methods  We performed a retrospective review of all patients who underwent LVAD implantation at the University of Rochester Medical Center from January 2008 to June 2017. Data were collected on patient characteristics, clinical aspects of gastrointestinal bleeding events, and procedural interventions. A Cox proportional hazard model was utilized to identify potential risk factors for a gastrointestinal bleeding event. Results  During the study period, 345 patients underwent LVAD implantation. Of these, 125 patients (36.2 %) experienced 297 gastrointestinal bleeding events resulting in 533 endoscopic procedures. The diagnostic yield of endoscopy in determining a bleeding source was 49.5 %. If required, therapeutic interventions were successful in achieving homeostasis in 96.2 % of procedures. Our 30-day overall post-procedure adverse event (AE) rate was 6.6 %. Procedure-related (bleeding, infection, and perforation) AEs were very minimal (2.8 %). A Cox proportional hazard model indicated that older age at implant, female sex, African-American race, diabetes mellitus, and pulmonary hypertension were statistically significant predictors of a gastrointestinal bleeding event following LVAD implantation. Conclusions  LVAD patients have a high risk of gastrointestinal bleeding. Endoscopy was able to safely locate a bleeding lesion in approximately half of our patients and was successful in treating bleeding lesions in a majority of the cases.

Patients with aortic stenosis have von Willebrand factor abnormalities and increased proliferation of endothelial colony forming cells

BACKGROUND

Patients with aortic stenosis (AS) can experience bleeding complications including gastrointestinal bleeding from angiodysplastic lesions due to acquired von Willebrand syndrome. Studies have pointed to a role for von Willebrand factor (VWF) in angiogenesis.

OBJECTIVE

The objective of this study was to assess VWF defects in AS patients over time and the impact on angiogenesis using patient-derived endothelial colony-forming cells (ECFCs).

PATIENTS/METHODS

Plasma sample collection and ECFC isolations were performed before valve replacement surgery, 3 to 5 days after, and 6 months after surgery. Plasma VWF antigen, activity, propeptide, collagen binding, multimers, factor VIII coagulant activity, and ADAMTS13 activity (a disintegrin-like and metalloprotease with thrombospondin type 1 motifs 13) were determined. ECFCs were assessed for VWF and angiopoietin-2 (Ang-2) storage and secretion, cell proliferation, and tubule formation in Matrigel.

RESULTS AND CONCLUSIONS

Aortic stenosis patients exhibited quantitative and qualitative abnormalities of VWF including significantly increased VWF antigen, activity, and propeptide levels following surgery (P < .01). Increased high molecular weight VWF multimers were observed at all time points and in particular 3 to 5 days after surgery (mean = 14% ± 6%) relative to before (mean = 10% ± 4%), suggesting increased proteolysis by ADAMTS13 pre-operatively in a shear-dependent manner. ECFCs from patients with aortic stenosis were more proliferative than controls (P < .05) and had increased retention of Ang-2 (P < .05) suggesting epigenetic modification of the cells. Overall, there are hemostatic changes in AS patients that are present before valve replacement surgery and these persist long after surgery has occurred. These findings have implications for the current clinical management of AS patients.

Effect of Angiotensin II Inhibitors on Gastrointestinal Bleeding in Patients With Left Ventricular Assist Devices

BACKGROUND

Angiotensin II receptor activation may result in angiogenesis, and ultimately arteriovenous malformations (AVM), through transforming growth factor (TGF)-β and angiopoietin-2 pathway activation.

OBJECTIVES

The goal of this study was to determine whether angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARB) were associated with lower risk of major gastrointestinal bleeds (GIB) and AVM-related GIBs in continuous-flow left ventricular assist device (CF-LVAD) patients.

METHODS

The authors reviewed HeartMate II CF-LVAD recipients between January 2009 and July 2016. Major GIBs were endoscopically confirmed requiring ≥2 U of packed red blood cells or resulting in death. ACE inhibitor/ARB dose was abstracted from medical records. ACE inhibitor/ARB exposure status was landmarked at 30 days post-operatively to avoid immortal time bias. Fine and Gray hazard models assessed the impact of ACE inhibitor/ARB therapy on major GIB and AVM-related GIB, whereas standard Cox regression assessed the impact on mortality, adjusting for baseline variables.

RESULTS

One-hundred and eleven patients were included with a mean 2.1 ± 1.4 years follow-up. Patients who received an ACE inhibitor/ARB within 30 days post-operatively had a 57% reduction in the risk of major GIB (adjusted hazard ratio [aHR]: 0.43; 95% confidence interval [CI]: 0.19 to 0.97; p = 0.042) and a 63% reduction in the risk of AVM-related GIB (aHR: 0.37; 95% CI: 0.16 to 0.84; p = 0.017). When the mean daily post-operative lisinopril-equivalent ACE inhibitor/ARB dose was >5 mg, the risk of major GIB decreased in a dose-threshold manner (aHR: 0.28; 95% CI: 0.09 to 0.85; p = 0.025).

CONCLUSIONS

ACE inhibitor/ARB therapy is associated with a protective effect of developing GIBs in CF-LVAD patients, with a dose threshold of >5 mg of daily lisinopril equivalence, possibly due to prevention of AVM formation.

The Predicament of Gastrointestinal Bleeding in Patients With a Continuous-Flow Left Ventricular Assist Device: Pathophysiology, Evaluation, and Management

Heart failure affects over 5 million Americans, with numbers expected to rise. While heart transplantation is the most effective long-term strategy for end-stage heart failure, there is a limited cardiac donor pool, and these organs are often unavailable at the time of need. Left ventricular assist devices, therefore, continue to be used to bridge this gap. Originally implanted as a bridge to transplant, these devices are now additionally utilized as destination therapy for patients ineligible for transplant. With the widespread applicability of these devices for not just temporary measures, but also for prolonged use, the short- and long-term impact on other organ systems has become more evident. For example, gastrointestinal (GI) bleeding, with an incidence approaching 30%, is one such complication post-continuous-flow left ventricular assist device implantation. This high incidence of GI bleeding is thought to stem from a combination of factors, including the need for concomitant anticoagulant and antiplatelet therapy, and intrinsic device-related properties resulting in acquired Von Willebrand disease and arteriovenous malformations. Due to the significant morbidity associated with these GI bleeding events, a standardized protocol optimizing medical and endoscopic management, alongside close coordination between the gastroenterology and cardiology services, should be advocated for and ultimately employed.

Acquired Von Willebrand Syndrome (AVWS) in cardiovascular disease: a state of the art review for clinicians

Von Willebrand Factor (vWF) is a large glycoprotein with a broad range of physiological and pathological functions in health and disease. While vWF is critical for normal hemostasis, vascular integrity and repair, quantitative and qualitative abnormalities in the molecule can predispose to serious bleeding and thrombosis. The heritable form of von Willebrand Disease was first described nearly a century ago, but more recently, recognition of an acquired condition known as acquired von Willebrand Syndrome (AVWF) has emerged in persons with hematological, endocrine and cardiovascular diseases, disorders and conditions. An in-depth understanding of the causes, diagnostic approach and management of AVWS is important for practicing clinicians.

Clinical Approach to Manage Gastrointestinal Bleeding with a Left Ventricular Assist Device (LVAD)

Left ventricular assist devices (LVADs) are an exceedingly important form of mechanical support for patients with end-stage heart failure. LVADs can be utilized both as a bridge to cardiac transplant and also as a definitive treatment. However, a few complications are associated with LVAD placement, the most common and cumbersome of which is gastrointestinal (GI) bleeding with an incidence of about 30%. These bleeding events often require transfusion therapy, but they are rarely fatal.

The etiologies of GI bleeding following LVAD are multifactorial and include unstable hemodynamics, an acquired von Willebrand factor (vWf) deficiency, impaired platelet aggregation, and activation of fibrinolytic systems. The treatment of choice in LVAD implantation-associated GI bleeding is endoscopy, which plays a vital role in both its diagnosis and management. Even so, its effectiveness in controlling post-LVAD implantation GI bleeding is still poorly ascertained. In this article, we will review the use of medication and alterations in the LVAD setting to prevent the occurrence of GI bleeding, as well as the findings of previously reported literature on LVAD implantation-associated GI bleeding.

COMPARISON OF THREE CONTROL STRATEGIES FOR AXIAL BLOOD PUMP

Facing the gradually increased prevalence of heart failure (HF) and the shortage of donated hearts, the blood pump is widely used to prolong the life of end-stage HF patients: however, the pump generates continuous flow under constant rotational speed, declining the arterial pulsatility and causing related complications. Previous studies show that synchronous copulsation might be the best control strategy for restoring pulsatility, but synchronous strategies are needed to monitor the phase of the heartbeat, which will make the controller complex and impair its robustness. Here, we compare constant speed, synchronous copulsation in a model of a cardiovascular system with a blood pump, which shows that copulsation offers more arterial pulsatility, less pump power-consumption, and thus better battery endurance, and constant speed offers a greater ventricular unloading effect. Meanwhile, we design a strategy based on transforming left ventricular pressure, which is easier to implement and has similar effect to synchronous copulsation.

Left Ventricular Assist Device: What the Internist Needs to Know. A Review of the Literature

Left ventricular assist devices (LVADs) have revolutionized therapy for patients with Stage D heart failure (HF) with reduced systolic function providing not only improved survival benefits but also meaningful changes in quality of life and functional capacity. With technological advances and improved durability of devices, length of survival has significantly improved. With continued organ donor shortage, LVADs are frequently serving as a substitute for cardiac transplant as destination therapy, particularly among the elderly. Internists not only face the important challenge of identifying the patients in need referral for these advanced therapies, they are also faced with the challenges of taking care of these patients. This review will help the internists to better understand the present status, indications and advances in LVADs and also understand the complications and adverse effects associated with these devices.

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 Gastrointestinal Complications From Ventricular Assist Devices is Increased by Non-Pulsatile Flow

BACKGROUND

Measurements of organ flow and perfusion during cardiopulmonary bypass suggest that perfusion of the splanchnic bed can be impaired by non-pulsatile flow. We postulated that non-pulsatile flow from centrifugal ventricular assist devices might also compromise splanchnic blood flow and cause bowel ischaemia especially in the period of circulatory instability early post-implant. The aim of the present studies was to compare the incidence of gastrointestinal (GI) complications in patients having a non-pulsatile device with the incidence in those having a pulsatile device.

METHODS

In a pilot study, the initial 12 patients who received the Ventrassist (Ventracor, Sydney, NSW, Australia) centrifugal, non-pulsatile device during the period from June 2003 to September 2005 at the Alfred Hospital, Melbourne were compared with 11 patients who received a Thoratec (Thoratec, Pleasanton, CA, USA), pulsatile, positive displacement device and the incidence was recorded of GI complications requiring an intervention either surgical, endoscopic or by interventional radiology. This was followed by a larger (full) study of a second cohort of similar ventricular assist device (VAD) patients from January 1992 until December 2012 comparing 53 patients having non-pulsatile devices and 110 having pulsatile devices.

RESULTS

In the pilot study, the overall incidence of complications in the non-pulsatile group (67%) was almost double that in the pulsatile group (36%) but the difference was not statistically significant (p = 0.15) because of the small number (n = 23) of participants. In the full study, all GI complications with either device occurred within the first 3 weeks post-implant. In the non-pulsatile patients, there was a higher incidence of GI bleeding, 23% vs 4% (p = 0.002), endoscopies, 24% vs 12% (p = 0.049). More patients with a non-pulsatile flow device had delayed absorption of nasogastric feeds than their pulsatile counterparts, 35% vs 7% (p < 0.0001). Patients with a non-pulsatile flow device had a higher overall rate of gastrointestinal complications than patients had with a pulsatile flow device, 56% vs 20% (p < 0.0001). After correcting for the other predictors, the odds of developing a gastrointestinal complication in the pulsatile group was significantly lower (odds ratio 0.07) than in the non-pulsatile device group (p < 0.0001).

CONCLUSIONS

We conclude that the use of non-pulsatile centrifugal VADs compared with pulsatile positive displacement VADs is associated with a higher incidence of both haemorrhagic and ischaemic complications in the gastro-intestinal system especially in the very early post-implant period. Whether these complications could be reduced in centrifugal devices by increasing their pulsatility is not clear and merits further research.

Laparoscopic procedures in patients with cardiac ventricular assist devices

BACKGROUND

Cardiac left ventricular assist device (LVAD) placement is a common therapy for heart failure. Non-cardiac surgical care of these patients can be complex given the need for anticoagulation, perioperative monitoring, comorbidities, and anatomical considerations due to the device itself. There are no guidelines or significant patient series reported to date for laparoscopic procedures in this population. We herein report the techniques and outcomes for commonly performed laparoscopic procedures in patients with LVADs at a high volume center.

METHODS

From our database of patients with ventricular assist devices, we retrospectively identified patients who underwent laparoscopic abdominal surgery. Intraoperative and perioperative data were collected, including anticoagulation management, transfusions and complications. Techniques and preoperative considerations from the surgeons were also compiled and described.

RESULTS

Of 374 patients that had placement of LVADs, 17 had an elective laparoscopic procedure: enteral access placement (n = 7), cholecystectomy (n = 6), hernia repair (n = 2), small bowel resection (n = 1) and splenectomy (n = 1). Preoperative evaluation routinely included radiologic imaging to evaluate driveline location. The most common abdominal entry technique was a periumbilical open Hasson technique (11/17). No cases were converted to open. Overall, the average blood loss was 132 ± 64 mL and the average operative time was 1.8 ± 0.3 h. Five of the 17 patients required intraoperative blood transfusion. No patients suffered perioperative thrombotic events or LVAD complications secondary to holding anticoagulation. No patients required interventions or reoperation for bleeding complications. There were no mortalities related to these procedures.

CONCLUSIONS

Laparoscopic abdominal procedures are safe and feasible in patients with LVADs. Although special consideration for bleeding and thrombotic risks, placement of ports and perioperative management is required, the presence of a LVAD itself should not be considered a contraindication for laparoscopic surgery and may in fact be the preferred method for access in these patients.

Preoperative Right-Sided Cardiac Congestion Is Associated with Gastrointestinal Bleeding in Patients with Continuous-Flow Left Ventricular Assist Devices

BACKGROUND

Large scale data on preoperative risk stratification for gastrointestinal bleeding (GIB) following continuous-flow left ventricular assist device (CF-LVAD) implantation are scarce.

AIMS

To identify independent predictors for GIB following CF-LVAD implantation.

METHODS

We conducted a retrospective cohort study of consecutive 243 patients who underwent CF-LVAD implantation (HeartMateII) from January 2009 to March 2015 at the University of Chicago Medical Center. GIB was defined as the presence of overt bleeding or occult GIB with ≥ 2 g/dl drop in hemoglobin (Hgb) from recorded baseline values and hemoccult-positive stool. The preoperative and postoperative data were reviewed.

RESULTS

Within a median follow-up duration of 408 (IQR 113-954) days, 83 (34%) patients developed GIB after a median of 149 (IQR 27-615) days after implantation of CF-LVAD. There were no significant differences between the groups of GIB and non-GIB with respect to preoperative demographics and comorbidity except for ethnicity. The source of bleeding was identified in 39 (47%) patients and arteriovenous malformation or submucosal streaming vessel was the most frequent cause of bleeding (18/39, 46%). Multivariate-adjusted analysis demonstrated preoperative central venous pressure (CVP) ≥ 18 mmHg (HR 3.56; 95% CI 1.16-10.9; p = 0.026), mean pulmonary artery pressure (mPA) ≥ 36 mmHg (HR 4.14; 95% CI 1.35-12.7; p = 0.013), and the presence of moderate/severe tricuspid valve disease (HR 1.01; 95% CI 1.01-3.86; p = 0.046) were associated with the risk of GIB.

CONCLUSIONS

In this study, preoperative right-sided cardiac congestion (i.e., increased CVP, mPA and the presence of moderate/severe tricuspid valve disease) was associated with GIB in patients with CF-LVAD.

Quantification of Von Willebrand Factor Cleavage by adamts-13 in Patients Supported by Left Ventricular Assist Devices

Patients supported by left ventricular assist devices (LVADs) often present with the loss of large von Willebrand factor (VWF) multimers. This VWF deficiency is believed to contribute to the bleeding diathesis of patients on LVAD support and is caused by excessive VWF cleavage by the metalloprotease ADAMTS-13 under high shear stress. However, only a small percentage of patients who have suffered the loss of large VWF multimers bleed. The actual rates of VWF cleavage in these patients have not been reported, primarily because of the lack of reliable detection methods. We have developed and validated a selected reaction monitoring (SRM) mass spectrometry method to quantify VWF cleavage as the ratio of the ADAMTS-13-cleaved peptide MVTGNPASDEIK to the ILAGPAGDSNVVK peptide. The rate of VWF cleavage was found to be 1.26% ± 0.36% in normal plasma. It varied significantly in patient samples, ranging from 0.23% to 2.5% of total VWF antigen, even though all patients had the loss of large VWF multimers. Von Willebrand factor cleavage was greater in post-LVAD samples from patients in whom bleeding had developed, but was mostly reduced in patients in whom thrombosis had developed. This SRM method is reliable to quantify the rate of VWF cleavage in patients on LVAD support.

Continuous-Flow LVAD Support Causes a Distinct Form of Intestinal Angiodysplasia

Rationale:

The objective of this autopsy study was to determine whether gastrointestinal angiodysplasia develops during continuous-flow left ventricular assist device (LVAD) support.

Objective:

LVAD support causes pathologic degradation of von Willebrand factor (vWF) and bleeding from gastrointestinal angiodysplasia at an alarming rate. It has been speculated that LVAD support itself may cause angiodysplasia. The relationship to abnormal vWF metabolism is unknown. We tested the hypothesis that abnormal gastrointestinal vascularity develops during continuous-flow LVAD support.

Methods and Results:

Small bowel was obtained from deceased humans, cows, and sheep supported with a continuous-flow LVAD (n=9 LVAD, n=11 control). Transmural sections of jejunum were stained with fluorescein isothiocyanate–conjugated isolectin-B4 for endothelium to demarcate vascular structures and quantify intestinal vascularity. Paired plasma samples were obtained from humans before LVAD implantation and during LVAD support (n=41). vWF multimers and degradation fragments were quantified with agarose and polyacrylamide gel electrophoresis and immunoblotting. Abnormal vascular architecture was observed in the submucosa of the jejunum of human patients, cows, and sheep supported with a continuous-flow LVAD. Intestinal vascularity was significantly higher after LVAD support versus controls (5.2±1.0% versus 2.1±0.4%, P =0.004). LVAD support caused significant degradation of high–molecular-weight vWF multimers (–9±1%, P <0.0001) and accumulation of low–molecular-weight vWF multimers (+40±5%, P <0.0001) and vWF degradation fragments (+53±6%, P <0.0001).

Conclusions:

Abnormal intestinal vascular architecture and LVAD-associated vWF degradation were consistent findings in multiple species supported with a continuous-flow LVAD. These are the first direct evidence that LVAD support causes gastrointestinal angiodysplasia. Pathologic vWF metabolism may be a mechanistic link between LVAD support, abnormal angiogenesis, gastrointestinal angiodysplasia, and bleeding.

Bleeding with the artificial heart: Gastrointestinal hemorrhage in CF-LVAD patients

Continuous-flow left ventricular assist devices (CF-LVADs) have significantly improved outcomes for patients with end-stage heart failure when used as a bridge to cardiac transplantation or, more recently, as destination therapy. However, its implantations carries a risk of complications including infection, device malfunction, arrhythmias, right ventricular failure, thromboembolic disease, postoperative and nonsurgical bleeding. A significant number of left ventricular assist devices (LVAD) recipients may experience recurrent gastrointestinal hemorrhage, mainly due to combination of antiplatelet and vitamin K antagonist therapy, activation of fibrinolytic pathway, acquired von Willebrand factor deficiency, and tendency to develop small intestinal angiodysplasias due to increased rotary speed of the pump. Gastrointestinal bleeding in LVAD patients remains a source of increased morbidity including the need for blood transfusions, extended hospital stays, multiple readmissions, and overall mortality. Management of gastrointestinal bleeding in LVAD patients involves multidisciplinary approach in stabilizing the patients, addressing risk factors and performing structured endoluminal evaluation with focus on upper gastrointestinal tract including jejunum to find and eradicate culprit lesion. Medical and procedural intervention is largely successful and universal bleeding cessation occurs in transplanted patients.

Combined Endoscopic and Surgical Treatment of Severe Gastrointestinal Bleeding in a Patient with Heart Assist Device under Therapeutic Anticoagulation

Gastrointestinal (GI) bleeding is a common complication after heart assist device placement. Reasons for bleeding are multifactorial. Endoscopic therapy is the treatment of choice, whereas invasive procedures are avoided in these critically ill patients. We present the case of a 65-year-old male patient experiencing severe GI bleeding after left ventricular assist device (LVAD) and right ventricular assist device (RVAD) placement with therapeutic anticoagulation. Endoscopically, multiple gastric bleeding sources were found but could not be treated effectively due to a large blood clot. A combined endoscopic and surgical treatment was initiated, including gastrotomy for blood clot removal, surgical transgastric suturing, endoscopic over-the-scope clip (OTSC) placement and hemospray application. Postoperative endoscopic visualization showed effective bleeding control. The patient unfortunately died due to causes unrelated to the treatment. This case shows that a minimal invasive combination of endoscopic and surgical techniques can be an alternative treatment for severe upper GI bleeding in critically ill and anticoagulated patients.

Current status of mechanical circulatory support for treatment of advanced end-stage heart failure: successes, shortcomings and needs

INTRODUCTION

Heart failure (HF) remains a major global burden in terms of morbidity and mortality. Despite advances in pharmacological and resynchronization device therapy, many patients worsen to end-stage HF. Although the gold-standard treatment for such patients is heart transplantation, there will always be a shortage of donor hearts. Areas covered: A left ventricular assist device (LVAD) is a valuable option for these patients as a bridge measure (to recovery, to candidacy for transplant, or to transplant itself) or as destination therapy. This review describes the current indications for and complications of the most commonly implanted LVADs. In addition, we review the potential and promising new LVADs, including the HeartMate 3, MVAD, and other LVADs. Studies investigating each were identified through a combination of online database and direct extraction of studies cited in previously identified articles. Expert commentary: The goal of LVADs has been to fill the gap between patients with end-stage HF who would likely not benefit from heart transplantation and those who could benefit from a donor heart. As of now, the use of LVADs has been limited to patients with end-stage HF, but next-generation LVAD therapy may improve both survival and quality of life in less sick patients.