Physiologic and pathologic changes in patients with continuous-flow ventricular assist devices. J Cardiovasc Transl Res. 2009;2:154-158. [PMID: 20559982 DOI: 10.1007/s12265-009-9092-y]

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.

Neurologic Complications in Patients With Left Ventricular Assist Devices

Left ventricular assist device (LVAD) use has revolutionised the care of patients with advanced heart failure, allowing more patients to survive until heart transplantation and providing improved quality for patients unable to undergo transplantation. Despite these benefits, improvements in device technology, and better clinical care and experience, LVADs are associated with neurologic complications. This review provides information on the incidence, risk factors, and management of neurologic complications among LVAD patients. Although scant guidelines exist for the evaluation and management of neurologic complications in LVAD patients, a high index of suspicion can prompt early detection of neurologic complications which may improve overall neurologic outcomes. A better understanding of the implications of continuous circulatory flow on systemic and cerebral vasculature is necessary to reduce the common occurrence of neurologic complications in this population.

Factors influencing the functional status of aortic valve in ovine models supported by continuous-flow left ventricular assist device

Objectives

An acute animal experiment was performed to observe factors influencing the functional status of the aortic valve functional status after continuous‐flow left ventricular assist device (CF‐LVAD) implantation in an ovine model, and a physiologic predictive model was established.

Methods

A CF‐LVAD model was established in Small Tail Han sheep. The initial heart rate (HR) was set to 60 beats/min, and grouping was performed at an interval of 20 beats/min. In all groups, the pump speed was started from 2000 rpm and was gradually increased by 50–100 rpm. A multi‐channel physiological recorder recorded the HR, aortic pressure, central venous pressure, and left ventricular systolic pressure (LVSP). A double‐channel ultrasonic flowmeter was used to obtain real‐time artificial vascular blood flow (ABF). A color Doppler ultrasound device was applied to assess the aortic valve functional status. Multivariate dichotomous logistic regression was used to screen significant variables for predicting the functional status of the aortic valve.

Results

Observational studies showed that ABF and the risk of aortic valve closure (AVC) were positively correlated with pump speed at the same HR. Meanwhile, the mean arterial pressure (MAP) was unaltered or slightly increased with increased pump speed. When the pump speed was constant, an increase in HR was associated with a decrease in the size of the aortic valve opening. This phenomenon was accompanied by an initial transient increase in the ABF and MAP, which subsequently decreased. Statistical analysis showed that the AVC was associated with increased pump speed (OR = 1.02, 95% CI = 1.01–1.04, p = 0.001), decreased LVSP (OR = 0.95, 95% CI = 0.91–0.98, p = 0.003), and decreased pulse pressure (OR = 0.82, 95% CI = 0.68–0.96, p = 0.026). ABF or MAP was negatively associated with the risk of AVC (OR < 1). The prediction model of AVC after CF‐LVAD implantation exhibited good differentiation (AUC = 0.973, 95% CI = 0.978–0.995) and calibration performance (Hosmer–Lemeshow χ² = 9.834, p = 0.277 > 0.05).

Conclusions

The pump speed, LVSP, ABF, MAP, and pulse pressure are significant predictors of the risk of AVC. Predictive models built from these predictors yielded good performance in differentiating aortic valve opening and closure after CF‐LVAD implantation.

National Landscape of Hospitalizations in Patients with Left Ventricular Assist Device. Insights from the National Readmission Database 2010-2015

The number of patients with left ventricular assist devices (LVAD) has increased over the years and it is important to identify the etiologies for hospital admission, as well as the costs, length of stay and in-hospital complications in this patient group. Using the National Readmission Database from 2010 to 2015, we identified patients with a history of LVAD placement using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code V43.21. We aimed to identify the etiologies for hospital admission, patient characteristics, and in-hospital outcomes. We identified a total of 15,996 patients with an LVAD, the mean age was 58 years and 76% were males. The most common cause of hospital readmission after LVAD was heart failure (HF, 13%), followed by gastrointestinal (GI) bleed (11.8%), device complication (11.5%), and ventricular tachycardia/fibrillation (4.2%). The median length of stay was 6 days (3-11 days) and the median hospital costs was $12,723 USD. The in-hospital mortality was 3.9%, blood transfusion was required in 26.8% of patients, 20.5% had acute kidney injury, 2.8% required hemodialysis, and 6.2% of patients underwent heart transplantation. Interestingly, the most common cause of readmission was the same as the diagnosis for the preceding admission. One in every four LVAD patients experiences a readmission within 30 days of a prior admission, most commonly due to HF and GI bleeding. Interventions to reduce HF readmissions, such as speed optimization, may be one means of improving LVAD outcomes and resource utilization.

Gastrointestinal Bleeding in Mechanical Cardiac Support

BACKGROUND

Mechanical cardiac support (MCS) is a lifesaving therapy option in patients with heart failure and other medical disorders. However, there is an associated risk of gastrointestinal bleeding (GIB). The goal of this study was to determine GIB incidence and associated risk factors.

METHODS

All patients at one institution from 2009 to 2018 under durable and nondurable support were retrospectively reviewed for GIB during their MCS period. Clinical records were evaluated for patient demographics, GIB characteristics, and interventions. Univariate and multivariate analyses were performed to compare patient groups.

RESULTS

A total of 427 patients were reviewed, with 111 (25.9%) patients representing 218 episodes of GIB during our study period. The incidence rate from support initiation to GIB was 44.9% by 6 months and 60.6% in 12 months, occurring at a mean of 216.7 days. Higher rates of bleeding were found in patients with hypertension (82% vs 71.5%; P = .03) and diabetes mellitus (62.2% vs 38.3%; P < .0001), as well as pulmonary (48.7% vs 35.4%; P = .014), hepatic (21.6% vs 10.4%; P = .003), and renal disease (48.7% vs 37.3%; P = .037). Endoscopy revealed an upper GI source in 56% (n = 123) of bleeds. The most common etiology of bleeding included angiodysplasia/vascular malformation (35.7%). Therapeutic intervention was performed in 109 (50%) cases, with only 1 surgical intervention.

DISCUSSION

Overall, GIB can be a significant adverse event in patients under mechanical cardiac support, so proper management of anticoagulation and early endoscopy evaluation remains of great importance.

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.

Outcomes in Patients with Left Ventricular Assist Devices, Pacemakers, and Implantable Cardioverter Defibrillators Undergoing Single Balloon Enteroscopy

OBJECTIVES

Obscure overt gastrointestinal bleeding can be challenging to evaluate in patients with electronic cardiac devices such as continuous flow left ventricular assist devices (LVADs), pacemakers (PPMs), and implantable cardioverter defibrillators (ICDs). Limited data exist on the utility and safety of single balloon enteroscopy (SBE) in patients with cardiac devices. We aimed to evaluate the safety, efficacy, diagnostic, and therapeutic outcomes of the aforementioned devices in patients undergoing SBE.

METHODS

A retrospective study was performed using the medical records of 57 patients undergoing SBE at our institution from 2010 to 2014. Patients were divided into two groups: those with cardiac devices and those without. Data on comorbidities, complications, findings, diagnostic, and therapeutic yield were compared. t Test and logistic regression assessed the association between dependent and independent variables. For continuous data, the results were summarized as mean difference and standard deviation. For dichotomous data, the results were summarized as odds ratio and 95% confidence intervals.

RESULTS

The overall age in patients with cardiac devices was 67.89 ± 6.96 versus 66.03 ± 11.95 years in the control. The cardiac device group was composed of 42.1% women; the control comprised 21.1% women. There were 19 patients with cardiac devices; 8 (LVAD + ICD), 1 (LVAD + PPM + ICD), 2 (PPM + ICD), 6 (PPM), 2 (ICD); 38 patients were in the control group. Patients with cardiac devices were hospitalized more often than patients without devices; this finding was not statistically significant (odds ratio 1.826, 95% confidence interval 0.544-6.128, P = 0.389). Procedure times were longer in the cardiac device group, 65.16 ± 49.92 minutes, when compared with the control, 57.40 ± 20.42, but it also did not reach statistical significance (mean difference 7.758, 95% confidence interval -11.360 to 26.876, P = 0.049). There was no statistically significant difference in major or minor events between patients with cardiac devices and the control group. Diagnostic and therapeutic yield and rebleeding rates were similar across both groups.

CONCLUSIONS

Patients in the cardiac device group did not appear to be at any more significant risk than those without cardiac devices. Furthermore, diagnostic and therapeutic yield and rebleeding rates appear to be similar across both groups. Clinicians may perform SBE in these patients safely and effectively, with good overall outcomes.

Timing of Gastrointestinal Bleeding After Implantation of Left Ventricular Assist Devices Associates With Anatomic Location, Presentation, and Management

BACKGROUND & AIMS

Continuous-flow left ventricular assist devices (LVADs) for advanced heart failure have been associated with gastrointestinal bleeding (GIB). We examined the association between time of GIB after LVAD implantation and bleeding location (determined by endoscopy), etiology, and patient outcomes.

METHODS

We performed a retrospective study of consecutive patients who underwent implantation of continuous-flow LVADs from 2008 through 2015. We analyzed data on anatomic location of GIB, etiology, length of hospital stay, transfusion requirement, time to endoscopy, and readmission to the hospital within 30 days (30-day readmission).

RESULTS

GIB developed in 59 of the 271 patients (22%). Higher proportions of patients with GIB during their index hospitalization for LVAD implantation had upper or lower GIB (86.7%) than patients with GIB during a subsequent hospitalization (50.0%; P = .013). Patients with GIB during their index hospitalization also had lower rates of middle GIB (0 vs 20.5%; P = .052), higher rates of overt GIB (100% vs 63.6%; P = .006), longer hospital stays (24 days vs 11 days; P < .001), and more transfusions before endoscopy (7 units vs 4 units; P = .021) than patients with GIB during a subsequent hospitalization. There were no significant differences between groups in time to endoscopy (2 days vs 2.5 days) or 30-day readmission (6.7% vs 9.3%). Angiodysplasias were identified in 100% of patients with middle GIB compared to 48.5% of patients with upper or lower GIB (P < .001) in whom a bleeding lesion was identified.

CONCLUSION

In a retrospective study of patients who underwent implantation of continuous-flow LVADs, we found that timing of GIB associates with the location and severity of bleeding. Although patients with LVADs have an overall increase in risk of middle GIB, patients with GIB during their index LVAD hospitalization should undergo initial evaluation by upper endoscopy and colonoscopy, due to insufficient time for development of small bowel angiodysplasias. Patients who later develop GIB should be evaluated early for middle GI bleeding.

Intracranial Hemorrhage in Patients with Durable Mechanical Circulatory Support Devices: Institutional Review and Proposed Treatment Algorithm

BACKGROUND

Spontaneous intracranial hemorrhage (ICH) is frequently managed in neurosurgery. Patients with durable mechanical circulatory support devices, including total artificial heart (TAH) and left ventricular assist device (LVAD), are often encountered in the setting of ICH. Although durable mechanical circulatory support devices have improved survival and quality of life for patients with advanced heart failure, ICH is one of the most feared complications following LVAD and TAH implantation. Owing to anticoagulation and clinically relevant acquired coagulopathies, ICH should be treated promptly by neurosurgeons and cardiac critical care providers. We provide an analysis of ICH in patients with mechanical circulatory support and propose a treatment algorithm.

METHODS

We retrospectively reviewed medical records from 2013-2016 for patients with a durable mechanical circulatory device at Banner-University of Arizona Medical Center Tucson. All patients with suspected ICH underwent computed tomography scan of the brain. Anticoagulation was managed by the cardiothoracic surgeon.

RESULTS

In 58 patients, an LVAD (n = 49), TAH (n = 10), or both (n = 1) were implanted. Both acquired von Willebrand disease and spontaneous ICH were diagnosed in 5 patients (8.6%) who underwent LVAD implantation. Seven neurosurgical procedures were performed in 2 patients. The overall mortality rate was 60%. Two patients had little or no deficits after treatment with modified Rankin Scale score of 1 and 2, respectively.

CONCLUSIONS

We propose a novel treatment algorithm to manage patients with a LVAD or TAH and ICH, implemented in a multidisciplinary manner to best avoid neurologic and cardiovascular complications.

Novel Use of Thalidomide in Recurrent Gastrointestinal Tract Bleeding in Patients with Left Ventricular Assist Devices: A Case Series

BACKGROUND

Bleeding is an important and common complication of left ventricular assist devices (LVADs). One of the common causes of gastrointestinal bleeding is arteriovenous malformations. However, the source of bleeding is often hard to identify. Thalidomide is efficacious in treatment of gastrointestinal (GI) bleeding in non-LVAD patients. We report our experience of the use of thalidomide in the treatment of GI bleeding in four patients with LVAD.

METHOD AND RESULTS

Four patients who had recurrent GI bleeding from May 2009 to December 2014 were started on thalidomide. All of them responded to treatment and had no further gastrointestinal bleeding while on thalidomide. One patient developed constipation, requiring thalidomide to be stopped. Another patient developed symptomatic neuropathy, that resolved with reduction of dosage.

CONCLUSION

Thalidomide appears safe and efficacious in LVAD patients with recurrent gastrointestinal bleeding.

Left ventricular assist device-induced reverse remodeling: it's not just about myocardial recovery

INTRODUCTION

The abnormal structure, function and molecular makeup of dilated cardiomyopathic hearts can be partially normalized in patients supported by a left ventricular assist device (LVAD), a process called reverse remodeling. This leads to recovery of function in many patients, though the rate of full recovery is low and in many cases is temporary, leading to the concept of heart failure remission, rather than recovery. Areas covered: We summarize data indicative of ventricular reverse remodeling, recovery and remission during LVAD support. These terms were used in searches performed in Pubmed. Duplication of topics covered in depth in prior review articles were avoided. Expert commentary: Although most patients undergoing mechanical circulatory support (MCS) show a significant degree of reverse remodeling, very few exhibit sufficiently improved function to justify device explantation, and many from whom LVADs have been explanted have relapsed back to the original heart failure phenotype. Future research has the potential to clarify the ideal combination of pharmacological, cell, gene, and mechanical therapies that would maximize recovery of function which has the potential to improve exercise tolerance of patients while on support, and to achieve a higher degree of myocardial recovery that is more likely to persist after device removal.

Challenges faced in long term ventricular assist device support

INTRODUCTION

The development of ventricular assist device (VAD) has been one of the revolutionary advancements in end-stage heart failure management. Although the device has developed and improved significantly over the last few decades, we still face multiple challenges.

AREAS COVERED

This review will discuss quality of life, survival, and clinically encountered complications in patients with VAD support. The literature was extensively reviewed for studies describing the above topic area. We describe the impact of major challenges faced in VAD support and discuss their future and expectations. Expert commentary: The technological advancement of VADs has contributed to major improvement of overall survival, enhancement of quality of life and decrease of incidence of complications. It is expected that technologies will continue to evolve. At the same time, the indications for and timing of device implantation, and selection of device type are continuously important in clinical practice setting.

New therapy, new challenges: The effects of long-term continuous flow left ventricular assist device on inflammation

Surgically implanted continuous flow left ventricular assist devices (CF-LVADs) are currently used in patients with end-stage heart failure (HF). However, CF-LVAD therapy introduces a new set of complications and adverse events in these patients. Major adverse events with the CF-LVAD include right heart failure, vascular dysfunction, stroke, hepatic failure, and multi-organ failure, complications that may have inflammation as a common etiology. Our aim was to review the current evidence showing a relationship between these adverse events and elevated levels of inflammatory biomarkers in CF-LVAD recipients.

Risk Factors and Outcomes of Gastrointestinal Bleeding in Left Ventricular Assist Device Recipients

Increasing use of left ventricular assist devices (LVADs) has been accompanied by rising incidence of gastrointestinal bleeding (GIB). Objectives of this study were to determine the yearly incidence of GIB in LVAD recipients, compare outcomes of continuous-flow (CF) and pulsatile-flow LVAD eras, and investigate for risk factors. The Healthcare Cost and Utilization Project-Nationwide Inpatient Sample database from 2005 to 2010 was analyzed. Primary outcome of interest was incidence of GIB in LVAD recipients. Multivariate logistic regression model was used to examine independent associations of GIB with risk factors and outcomes. An estimated 8,879 LVAD index admissions and 8,722 readmissions in LVAD recipients over 6 years were analyzed. The yearly incidence of GIB after LVAD implantation increased from 5% in 2005 to 10% in 2010. On multivariate regression analysis, the odds of GIB was 3.24 times greater (95% confidence interval 1.53 to 6.89) in the era of CF LVADs than in the era of pulsatile-flow LVADs. Compared to their younger counterparts, in LVAD recipients aged >65 years, the adjusted odds of GIB was 20.5 times greater (95% confidence interval 2.24 to 188). GIB did not significantly increase the inhospital mortality but increased the inpatient length of stay. In conclusion, the incidence of GIB in LVAD recipients has increased since the use of CF LVADs has increased, leading to greater inpatient lengths of stay and hospital charges. Older recipients of CF LVADs appear to be at a greater risk of GIB.

Late Complications Following Continuous-Flow Left Ventricular Assist Device Implantation

Left ventricular assist devices have become standard therapy for patients with end-stage heart failure. They represent potential long-term solutions for a growing public health problem. However, initial enthusiasm for this technology has been tempered by challenges posed by long-term support. This review examines these challenges and out current understanding of their etiologies.

Antithrombotic therapy for ventricular assist devices in children: do we really know what to do?

The use of ventricular assist devices (VADs) in children is increasing. Stroke and device-related thromboembolism remain the most feared complications associated with VAD therapy in children. The presence of a VAD causes dysregulation of hemostasis due to the presence of foreign materials and sheer forces intrinsic to the device resulting in hypercoagulability and potentially life-threatening thrombosis. The use of antithrombotic therapy in adults with VADs modulates this disruption in hemostasis, decreasing the risk of thrombosis. Yet, differences in hemostasis in children (developmental hemostasis) may result in variances in dysregulation by these devices and preclude the use of adult guidelines. Consequently, pediatric device studies must include safety and efficacy estimates of device-specific antithrombotic therapy guidelines. This review will discuss mechanisms of hemostatic dysregulation as it pertains to VADs, goals of VAD antithrombotic therapy for children and adults, and emerging antithrombotic strategies for VAD use in children.

GI bleeding in patients with continuous-flow left ventricular assist devices: a systematic review and meta-analysis

BACKGROUND

Patients with left ventricular assist devices (LVADs) are at increased risk of GI bleeding (GIB), primarily from GI angiodysplastic lesions (GIAD).

OBJECTIVE

To perform meta-analysis of the medical literature in order to determine prevalence and risk factors for GIB.

DESIGN

A literature search was performed to identify studies reporting GIB in LVAD patients. We extracted rates of prevalence, rebleeding, and overall mortality from each study. Pooled event rates and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated.

SETTING

Meta-analysis of 17 case-control and cohort studies.

PATIENTS

A total of 1839 LVAD patients of whom 1697 (92%) had continuous-flow LVADs.

RESULTS

The pooled prevalence of GIB in LVAD patients was 23% (95% CI, 20.5%-27%). Subgroup analysis demonstrated that older age (standard difference in means (SDm), 0.69; 95% CI, 0.23-1.15), and elevated creatinine (SDm, 0.65; 95% CI, 0.12-1.18, P = .02) were associated with GIB. Risk factors not associated with GIB included LVAD as destination therapy (OR 1.85; 95% CI, 0.8-4.3), prior history of GIB (OR 2.22; 95% CI, 0.83-5.96), hypertension (OR 1.6; 95% CI, 0.87-2.97), and/or the presence of a continuous-flow LVAD (OR 4.5; 95% CI, 2.1-9.5). Recurrence of GIB occurred in 9.3% (95% CI, 7%-12%), with a GIB mortality rate of 23% (95% CI, 16%-32%). The pooled event rates were 48% (95% CI, 39%-57%) for upper GIB, 22% (95% CI, 16%-31%) for lower GIB, and 15% (95% CI, 8%-25%) for small-bowel bleeding. GIAD in the proximal GI tract were the most common cause of GIB (29%).

LIMITATIONS

Lack of information regarding endoscopic therapy and follow-up in most studies.

CONCLUSIONS

The prevalence of GIB is increased in patients with continuous-flow LVADs, primarily secondary to the presence of GIAD.

Outcomes of continuous flow ventricular assist devices

Heart transplantation is commonplace, the supply is limited. Many exciting changes in the field of mechanical circulatory support have occurred in the past few years, including the axial flow pump. Left ventricular assist device (LVAD) therapy is ever evolving. As the use of LVAD therapy increases it is important to understand the indications, surgical considerations and outcomes.

Gastrointestinal bleeding in patients with ventricular assist devices: what every cardiac nurse should know

Patients with end-stage heart failure are increasingly being treated with implantation of a long-term ventricular assist device. As the use of these devices has grown, health care providers have been faced with managing clinically significant gastrointestinal bleeding in this population. Gastrointestinal bleeding is not uncommon and is reported to occur in 13% to 44% of patients treated with ventricular assist devices. Interestingly, because patients with ventricular assist devices are housed on units accustomed to managing the device, cardiac nurses are often asked about the management of gastrointestinal bleeding. This article describes the possible causes of, the array of diagnostic procedures for, and treatments for this complication. It is critical to develop an understanding of this topic so cardiac nurses can partner with other subspecialty groups to manage this population.

Management of patients with implanted ventricular assist devices for noncardiac surgery: a clinical review

While originally primarily used as bridge to cardiac transplantation and bridge to recovery, more commonly ventricular assist devices (VADs) are being inserted as destination therapy. These patients are being discharged from transplant and mechanical assist centers, living as outpatients, and thus the pool of community-dwelling patients with VADs continues to expand. Not infrequently they present for surgical procedures either directly related to the device itself or more often incidental to the fact that they have a VAD. This scenario may be more common in patients with VADs placed for destination therapy because these patients tend to be older and have more comorbidities and are living longer with their device. Thus, it is important for all anesthesiologists to be aware of the special anesthesia needs of patients with VADs requiring noncardiac surgery.

Improving survival during heart transplantation: diagnosis of antibody-mediated rejection and techniques for the prevention of graft injury

The diagnosis of antibody-mediated rejection (AMR) has presented a challenge due to the pleiomorphic immunologic responses that represent the condition. A consensus with regard to its pathological diagnosis continues to evolve. Due to an increasing number of sensitized patients undergoing heart transplantation, its incidence appears to be on the rise and the condition is associated with worse outcomes than acute cellular rejection. Treatment of AMR is also more difficult and response to increases in conventional immunosuppression is often limited. Risk factors for AMR include the use of ventricular assist devices, prior exposure to blood products, allografts and multiparity. Detection of alloantibodies with a high specificity and sensitivity allows risk stratification of recipients at potential risk of AMR. Desensitization and AMR treatment strategies are focused on several therapeutic targets, including suppression of T and B cells and elimination or inhibition of circulating antibodies.

Gastrointestinal bleeding with the HeartMate II left ventricular assist device

BACKGROUND

Continuous flow left ventricular assist devices (CF-LVADs) have yielded improved outcomes compared with pulsatile flow devices for patients on long-term support. However, significant rates of gastrointestinal bleeding (GIB) have been observed during CF-LVAD support.

METHODS

From March 2006 through March 2011, 86 patients with chronic heart failure underwent implantation of a CF-LVAD (HeartMate II; Thoratec Corp., Pleasanton, CA). Records were reviewed to determine the prevalence of post-implant GIB, location of the bleeding site and associated morbidity and mortality. Uni- and multivariate analyses were conducted to identify independent predictors of GIB.

RESULTS

GIB occurred in 19 patients (22.1%) with a duration of support that ranged from 5 to 456 days. Sources of GIB included small bowel and rectum in 6 patients each, large bowel in 2 patients and stomach in 1 patient. No definite source was identified in 4 patients. There were no deaths referable to GIB. Recurrent GIB occurred in 4 patients. History of a GIB prior to LVAD implant was the only variable significantly different between patients with and without post-implant GIB (21.1% vs 10.4%, p = 0.016), and was the only independent predictor of GIB (OR = 2.24, 95% CI 2.121 to 2.435, p = 0.004).

CONCLUSIONS

Gastrointestinal bleeding is a frequent source of morbidity for patients on HeartMate II LVAD support but does not significantly impact survival. As implantation of CF-LVADs with non-pulsatile flow gains popularity for both bridge-to-transplant and destination therapy, a better understanding of the pathophysiology of GIB in these patients will be needed for minimizing this complication.

Mechanisms of bleeding and approach to patients with axial-flow left ventricular assist devices

Axial-flow LVADs have become an integral tool in the management of end-stage heart failure. Consequently, nonsurgical bleeding has emerged as a major source of morbidity and mortality in this fragile population. The mechanisms responsible for these adverse events include acquired von Willebrand disease, GI tract angiodysplasia formation, impaired platelet aggregation, and overuse of anticoagulation therapy. Because of ongoing concerns for pump thrombosis and thromboembolic events, the thrombotic/bleeding paradigm has led to a difficult clinical dilemma for those managing patients treated with axial flow LVADs. As the field progresses, advances in the understanding of the pathological mechanisms underlying bleeding/thrombosis risk, careful risk stratification, and potential use of novel anticoagulants will all play a role in the management of the LVAD patient.

Arteriovenous malformation and gastrointestinal bleeding in patients with the HeartMate II left ventricular assist device

BACKGROUND

In this study we investigated gastrointestinal (GI) bleeding and its relationship to arteriovenous malformations (AVMs) in patients with the continuous-flow HeartMate II (HMII) left ventricular assist device (LVAD).

METHODS

The records of 172 patients who received HMII support between November 2003 and June 2010 were reviewed. Patients were considered to have GI bleeding if they had 1 or more of the following symptoms: guaiac-positive stool; hematemesis; melena; active bleeding at the time of endoscopy or colonoscopy; and blood within the stomach at endoscopy or colonoscopy. The symptom(s) had to be accompanied by a decrease of >1 g/dl in the patient's hemoglobin level. The location of the bleeding was identified as upper GI tract, lower GI tract or both according to esophagogastroduodenoscopy, colonoscopy, small-bowel enteroscopy or mesenteric angiography. Post-LVAD implantation anti-coagulation therapy consisted of warfarin, aspirin and dipyridamole.

RESULTS

Thirty-two of the 172 patients (19%) had GI bleeding after 63 ± 62 (range 8 to 241) days of HMII support. Ten patients had GI bleeding from an AVM; these included 3 patients who had 2 bleeding episodes and 2 patients who had 5 episodes each. Sixteen patients had upper GI bleeding (10 hemorrhagic gastritis, 4 gastric AVM, 2 Mallory-Weiss syndrome), 15 had lower GI bleeding (6 diverticulosis, 6 jejunal AVM, 1 drive-line erosion of the colon, 1 sigmoid polyp, 1 ischemic colitis) and 1 had upper and lower GI bleeding (1 colocutaneous and gastrocutaneous fistula). All GI bleeding episodes were successfully managed medically.

CONCLUSIONS

Arteriovenous malformations can cause GI bleeding in patients with continuous-flow LVADs. In all cases in this series, GI bleeding was successfully managed without the need for surgical intervention.