Clinical outcomes with use of erythropoiesis stimulating agents in patients with the HeartMate II left ventricular assist device

Iron Deficiency in Patients with Left Ventricular Assist Devices

Iron deficiency is a common and independent predictor of adverse outcomes in patients with heart failure. The implications of iron deficiency in patients implanted with a left ventricular assist device (LVAD) are less established. This review recaps data on the prevalence, characteristics and impact of Iron deficiency in the LVAD population. A systematic search yielded eight studies involving 517 LVAD patients, with iron deficiency prevalence ranging from 40% to 82%. IV iron repletion was not associated with adverse events and effectively resolved iron deficiency in most patients. However, the effects of iron deficiency and iron repletion on post-implant survival and exercise capacity remain unknown. Although iron deficiency is highly prevalent in LVAD patients, its true prevalence and adverse effects may be misestimated due to inexact diagnostic criteria. Future randomised controlled trials on IV iron treatment in LVAD patients are warranted to clarify the significance of this common comorbidity.

Predictors of gastrointestinal bleeding in patients following left ventricular assist device implantation: a systematic review and meta-analysis

Aim: Our study aims to provide a more holistic understanding of the available data and predictive risk factors for gastrointestinal bleed (GIB). Materials & methods: We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials and Web of Science Core Collection and calculated relative risk and meta-regression was utilized to evaluate for risk factors in order to assess the effect of covariates. Results: Our meta-analysis reported a pooled prevalence rate of GIB of 24.4%. Meta-regression analysis did not yield a statistically significant association between GIB and risk factors, including age, gender, hypertension, chronic kidney disease and diabetes. Conclusion: Studies investigating larger sample sizes are required for conclusive findings.

Epoetin alfa in Pediatric Patients With Ventricular Assist Devices: Is It Safe?

Anemia is a predictor of morbidity and mortality in both pediatric and adult patients with heart failure. This risk is increased in patients who require ventricular assist device (VAD) placement. The most common mechanism suggested for why these patients develop anemia is chronic inflammation caused by the immune system reacting to the VAD components. The inflammatory response that occurs can suppress erythropoiesis by inhibiting production of erythropoietin. Studies have demonstrated that anemic VAD patients have lower-than-expected erythropoietin levels, which leads to the consideration of erythropoiesis-stimulating agents (ESAs) in this population. Therapy with ESAs can increase hemoglobin and hematocrit levels, thereby decreasing the need for transfusions, subsequently reducing the risk of anti-human leukocyte antigen antibody development. Concerns that ESAs may increase the risk of thrombotic complications in a population already plagued with physiologic disturbances due to the VAD device remain a main barrier in routine use of these medications. The goal of this case series is to discuss a single center's experience with epoetin alfa in pediatric VAD patients at an academic children's hospital. A total of 4 patients were included with no evidence of adverse effects during a total of 120 patient-days of epoetin therapy. One patient was able to discontinue ESA therapy secondary to robust improvement in cell line counts at the time of discharge, while the other 3 patients received heart transplant prior to the discontinuation of ESA therapy. An increase in hematocrit of 1% to 5.5% was seen from epoetin initiation to discontinuation.

Anemia and outcomes following left ventricular assist device implantation

BACKGROUND

Patients with concomitant anemia and congestive heart failure have poor outcomes. The prevalence and clinical risk of anemia in patients receiving durable left ventricular assist devices (LVAD) remain unknown.

METHODS

We retrospectively analyzed patients who underwent LVAD implantation between 2014 and 2018. The association between hemoglobin level at the time of index discharge and the one-year composite endpoint of heart failure readmissions or hemocompatibility-related adverse events was investigated.

RESULTS

A total of 168 patients (57 [48, 66] years old, 123 males) were included and stratified into a classification of anemia (hemoglobin <9.7 g/dl, N = 99) or non-anemia (N = 69). The anemia group had a higher one-year incidence of the composite endpoint (56% vs 36%, p = .013) with an adjusted hazard ratio of 1.83 (95% confidence interval 1.08-2.82). Patients with anemia also experienced suboptimal bi-ventricular unloading.

CONCLUSIONS

Anemia was prevalent in LVAD patients and associated with a greater risk of heart failure and hemocompatibility-related adverse events. The optimal threshold for therapeutic intervention in response to post-LVAD anemia needs further investigation.

Endocrine Challenges in Patients with Continuous-Flow Left Ventricular Assist Devices

Heart failure (HF) remains a leading cause of morbidity, hospitalization, and mortality worldwide. Advancement of mechanical circulatory support technology has led to the use of continuous-flow left ventricular assist devices (LVADs), reducing hospitalizations, and improving quality of life and outcomes in advanced HF. Recent studies have highlighted how metabolic and endocrine dysfunction may be a consequence of, or associated with, HF, and may represent a novel (still neglected) therapeutic target in the treatment of HF. On the other hand, it is not clear whether LVAD support, may impact the outcome by also improving organ perfusion as well as improving the neuro-hormonal state of the patients, reducing the endocrine dysfunction. Moreover, endocrine function is likely a major determinant of human homeostasis, and is a key issue in the recovery from critical illness. Care of the endocrine function may contribute to improving cardiac contractility, immune function, as well as infection control, and rehabilitation during and after a LVAD placement. In this review, data on endocrine challenges in patients carrying an LVAD are gathered to highlight pathophysiological states relevant to this setting of patients, and to summarize the current therapeutic suggestions in the treatment of thyroid dysfunction, and vitamin D, erythropoietin and testosterone administration.

Ventricular Assist Devices and Chronic Kidney Replacement Therapy: Technology and Outcomes

Heart failure and kidney failure are very common conditions, precipitating and exacerbating each other. Left ventricular assist devices (LVADs) represent a relatively new technology for treatment of advanced heart failure. Kidney dysfunction, if present, makes candidate selection for LVADs challenging and contributes to multiple complications while the patients are on an LVAD support. Although kidney function generally improves after LVAD implantation, some patients develop acute and then chronic kidney disease sometimes requiring kidney replacement therapies (KRTs). Overall, chronic KRT in LVAD recipients is feasible and well tolerated, but routine technique of blood pressure monitoring should be adjusted to the continuous blood flow. Both hemodialysis and peritoneal dialysis can be used. Unique challenges for chronic KRT posed by the presence of LVAD are discussed in this review.

Outcomes Among Patients With Left Ventricular Assist Devices Receiving Maintenance Outpatient Hemodialysis: A Case Series

RATIONALE & OBJECTIVE

The incidence of left ventricular assist device (LVAD) implantation as destination therapy for heart failure is increasing and kidney failure requiring maintenance hemodialysis is a common complication. Because little is known about the safety or efficacy of outpatient hemodialysis among patients with LVADs, this study sought to describe their clinical course.

STUDY DESIGN

Case series of patients with an LVAD undergoing maintenance outpatient hemodialysis whose clinical data were obtained from an electronic medical record.

SETTING & PARTICIPANTS

Adults who received an LVAD, survived to hospital discharge, and were subsequently treated with maintenance hemodialysis by a not-for-profit dialysis provider between 2011 and 2019.

RESULTS

11 patients were included. 6 had a known history of chronic kidney disease. Patients underwent outpatient hemodialysis for a mean duration of 165.2 (range, 31-542) days, during which they were treated with 544 total dialysis sessions. 6 of these sessions were stopped early due to dialysis-related adverse events (1.1%). More than 80% of follow-up time was spent out of the hospital; however, 55% of patients were rehospitalized within 1 month of starting outpatient hemodialysis. The most common reason for hospitalization was infection (32%), followed by hypervolemia (14%), and cerebrovascular accident or transient ischemic attack (11%). 4 patients recovered kidney function, 1 underwent combined heart and kidney transplantation, 2 continued treatment, 2 died, and 2 were lost to follow-up.

LIMITATIONS

Retrospective design, small number of cases, and lack of complete follow-up data.

CONCLUSIONS

Approximately half the patients with complete follow-up either recovered kidney function or underwent combined heart and kidney transplantation. This case series demonstrates that outpatient hemodialysis centers, in partnership with LVAD treatment teams, can successfully provide hemodialysis to patients on LVAD support.

Patients with left ventricle assist devices presenting for thoracic surgery and lung resection: tips, tricks and evidence

PURPOSE OF REVIEW

Over a thousand left ventricular-assist device (LVAD) implants were performed for heart failure destination therapy in 2017. With increasing survival, we are seeing increasing numbers of patients present for noncardiac surgery, including resections for cancer. This article will review the relevant literature and guidelines for patients with LVADs undergoing thoracic surgery, including lung resection.

RECENT FINDINGS

The International Society for Heart and Lung Transplant Mechanically Assisted Circulatory Support Registry has received data on more than 16 000 patients with LVADs. Four-year survival is more than 60% for centrifugal devices. There are increasing case reports, summaries and recommendations for patients with LVADs undergoing noncardiac surgery. However, data on thoracic surgery is restricted to case reports.

SUMMARY

Successful thoracic surgery requires understanding of the LVAD physiology. Modern devices are preload dependent and afterload sensitive. The effects of one-lung ventilation, including hypoxia and hypercapnia, may increase pulmonary vascular resistance and impair the right ventricle. Successful surgery necessitates a multidisciplinary approach, including thorough preoperative assessment; optimization and planning of intraoperative management strategies; and approaches to anticoagulation, right ventricular failure and LVAD flow optimization. This article discusses recent evidence on these topics.

Predicting Transfusions During Left Ventricular Assist Device Implant

Perioperative bleeding and transfusion cause morbidity and mortality in patients receiving left ventricular assist devices (LVADs). We assessed factors associated with transfusions within 30 days of durable LVAD implantation and the clinical outcomes associated with transfusions. A retrospective cohort study of patients undergoing initial durable LVAD implantation between 2014 and 2016 was performed. Rates of packed red blood cell (PRBC) or other blood product transfusions (platelets or fresh frozen plasma) were assessed. Ordinal multivariable regression analysis was performed to determine factors independently associated with transfusion. Analysis included 156 patients, mean age 54.6 years and 74.4% male, who received a mean of 11.7 units of PRBC and 10.0 units of other products within 30 days. Preimplant mechanical ventilation, dialysis, higher INR, previous sternotomy, higher model for end-stage liver disease score, and lower hemoglobin were associated with increased PRBC transfusion rates. Higher preoperative central venous pressure, mechanical ventilation, concomitant surgical procedures, previous sternotomy, and lower hemoglobin were associated with increased PRBC transfusion rates within 48 hours of implant (adjusted odds ratio [OR] 1.46, P = 0.013 per 5 mm Hg). There were no significant associations with ferritin (adjusted OR 1.00, P = 0.236) or transferrin saturation (adjusted OR 1.17, P = 0.068). Transfusions were associated with an increase in ventilation duration, intensive care unit length of stay, reoperation for bleeding, and all-cause mortality. In patients undergoing LVAD implantation, perioperative blood product exposure is common and associated with increased morbidity and mortality. Elevated central venous pressure and anemia are potentially modifiable factors associated with increased early PRBC transfusion rates.

Cardiac prostheses-related hemolytic anemia

Hemolysis is an unintended sequel of temporary or permanent intracardiac devices. However, limited data exist on the characteristics and treatment of hemolysis in patients with cardiac prostheses. This entity, albeit uncommon, often poses significant diagnostic and management challenges to the clinical cardiologist. In this article, we aim to provide a contemporary overview of the incidence, mechanisms, diagnosis, and management of cardiac prosthesis‐related hemolysis.

Prevalence of Anemia and Iron Deficiency in Pediatric Patients on Ventricular Assist Devices

The prevalence and characteristics of anemia and iron deficiency in children supported by a ventricular assist device (VAD) are unknown. Patients <21 years of age on durable VAD support for ≥7 days at Texas Children's Hospital from 2006 to 2015 were retrospectively reviewed. Red blood cell (RBC) and iron deficiency indices in pulsatile VAD (P-VAD) and continuous-flow VAD (CF-VAD) were evaluated. Anemia, iron deficiency, and iron therapy regimens were identified. Seventy-six VAD implants in 74 patients were included: 45 P-VAD and 31 CF-VAD. Overall, 48% (36/75) of patients were anemic at VAD implant, with 67% of CF-VAD and 34% of P-VAD affected. Iron deficiency was seen in 52% (39/75) of patients at implant (similar in both groups). At explant, 71% (53/75) had anemia (similar in both groups). No patients had microcytosis. Iron supplementation was given to 20 patients, with four receiving target replacement therapy (2-6 mg/kg/d × 90 days). Red blood cell transfusion volumes were higher for P-VAD versus CF-VAD. We concluded that anemia and iron deficiency are common in pediatric VAD patients. Pulsatile VAD patients tend to develop anemia over the course of VAD support. Lack of microcytosis, likely masked by high RBC transfusions, suggests that specific iron studies are necessary to identify iron deficiency.

Relationship Between Anticoagulation Intensity and Thrombotic or Bleeding Outcomes Among Outpatients With Continuous-Flow Left Ventricular Assist Devices

BACKGROUND

We evaluated thrombotic and bleeding outcomes in patients with continuous-flow left ventricular assist devices (CF-LVADs), stratified by anticoagulation intensity. Previous studies of outpatients with CF-LVADs have suggested that target international normalized ratio (INR) values <2.5 (range, 2-3) may be used. However, recent studies reported an increase in pump thrombosis among CF-LVADs, especially within the first 6 months of implant.

METHODS AND RESULTS

We retrospectively reviewed 249 outpatients at our center who received a CF-LVAD between January 2005 and August 2013. Using Poisson models, we analyzed their 10 927 INRs to determine INR-specific rates of thrombotic (ischemic stroke and suspected pump thrombosis) and hemorrhagic (gastrointestinal bleeding and hemorrhagic stroke) events occurring outside of the hospital. In multivariate analyses, we adjusted for age, sex, atrial fibrillation, coronary disease, and LVAD type as time-dependent Cox proportional hazard models. During a mean follow-up of 17.6±13.6 months, thrombotic events occurred in 46 outpatients. The highest event rate (0.40 thrombotic events per patient-year) was in the INR range of <1.5, but INR values of 1.5 to 1.99 also had high rates (0.16 thrombotic events per patient-year). INR was inversely associated with thrombotic events (hazard ratio, 0.40; 95% confidence interval, 0.22-0.72; P=0.002). The optimal INR based on weighted mortality of thrombotic and bleeding events was 2.6.

CONCLUSIONS

INR is inversely related to thrombotic events occurring outside of the hospital among patients supported with CF-LVADs. INR values <2.0 increase the rate of thrombotic events occurring outside of the hospital among patients supported with CF-LVADs.

Preoperative Proteinuria and Reduced Glomerular Filtration Rate Predicts Renal Replacement Therapy in Patients Supported With Continuous-Flow Left Ventricular Assist Devices

Background—

Renal failure requiring renal replacement therapy (RRT) has detrimental effects on quality of life and survival of patients with continuous-flow left ventricular assist devices (CF-LVADs). Current guidelines do not offer a decision-making algorithm for CF-LVAD candidates with poor baseline renal function. Objective of this study was to identify risk factors associated with RRT after CF-LVAD implantation.

Methods and Results—

Three hundred and eighty-nine consecutive patients underwent contemporary CF-LVAD implantation at the Columbia University Medical Center between January 2004 and August 2015. Baseline demographics, comorbid conditions, clinical risk scores, and renal function were analyzed in patients with or without RRT after CF-LVAD implantation. Time-dependent receiver-operating characteristic curve analysis was performed to define optimal cutoffs for continuous risk factors. Forty-four patients (11.6%) required RRT during a median follow-up of 9.9 months. Patients requiring RRT had significantly worse renal function, lower hemoglobin, and increased proteinuria at baseline. Low estimated glomerular filtration rate (<40 mL/min/1.73 m 2 ) and proteinuria (urine protein to creatinine ratio ≥0.55 mg/mg) were significant predictors of RRT after CF-LVAD support. Dipstick proteinuria was also a significant predictor of RRT after CF-LVAD implantation. Patients with both low estimated glomerular filtration rate and proteinuria had highest risk of RRT (63.6%) compared with those with either low estimated glomerular filtration rate or proteinuria (18.7%) and those with neither of these risk factors (2.7%) at 1-year follow-up (log-rank P <0.001).

Conclusions—

Estimated glomerular filtration rate and proteinuria are predictors RRT after CF-LVAD implantation and should be routinely assessed in CF-LVAD candidates to guide decision making.

Relationship Between Anticoagulation Intensity and Thrombotic or Bleeding Outcomes Among Outpatients With Continuous-Flow Left Ventricular Assist Devices

BACKGROUND

We evaluated thrombotic and bleeding outcomes in patients with continuous-flow left ventricular assist devices (CF-LVADs), stratified by anticoagulation intensity. Previous studies of outpatients with CF-LVADs have suggested that target international normalized ratio (INR) values <2.5 (range, 2-3) may be used. However, recent studies reported an increase in pump thrombosis among CF-LVADs, especially within the first 6 months of implant.

METHODS AND RESULTS

We retrospectively reviewed 249 outpatients at our center who received a CF-LVAD between January 2005 and August 2013. Using Poisson models, we analyzed their 10 927 INRs to determine INR-specific rates of thrombotic (ischemic stroke and suspected pump thrombosis) and hemorrhagic (gastrointestinal bleeding and hemorrhagic stroke) events occurring outside of the hospital. In multivariate analyses, we adjusted for age, sex, atrial fibrillation, coronary disease, and LVAD type as time-dependent Cox proportional hazard models. During a mean follow-up of 17.6±13.6 months, thrombotic events occurred in 46 outpatients. The highest event rate (0.40 thrombotic events per patient-year) was in the INR range of <1.5, but INR values of 1.5 to 1.99 also had high rates (0.16 thrombotic events per patient-year). INR was inversely associated with thrombotic events (hazard ratio, 0.40; 95% confidence interval, 0.22-0.72; P=0.002). The optimal INR based on weighted mortality of thrombotic and bleeding events was 2.6.

CONCLUSIONS

INR is inversely related to thrombotic events occurring outside of the hospital among patients supported with CF-LVADs. INR values <2.0 increase the rate of thrombotic events occurring outside of the hospital among patients supported with CF-LVADs.

Anticoagulation management in mechanical circulatory support

Heart failure continues to be a worldwide epidemic, effecting over 23 million persons. Despite advances in medical therapy, the disease is progressive and a significant proportion of patients will need advanced heart replacement therapy. Continuous flow assist devices have become a standard approach for many patients both as a bridge to cardiac transplantation and as destination therapy (DT). However, device related complications such as bleeding and thrombosis continue to hinder further advancements of this technology. The field is rapidly advancing and efforts to reduce pump complications are directed towards improving hemocompatibility and maximizing blood flow without clinically significant hemolysis, areas of stasis or turbulent flow.