Low thromboembolism and pump thrombosis with the HeartMate II left ventricular assist device: analysis of outpatient anti-coagulation

Anesthetic management for non-cardiac surgery in patients with left ventricular assist devices

With the growing number of patients undergoing left ventricular assist device (LVAD) implantation and improved survival in this population, more patients with LVADs are presenting for various types of non-cardiac surgery. Therefore, anesthesiologists need to understand the physiology and adequately prepare for the perioperative management of this unique patient population. This review addresses perioperative considerations and intraoperative management for the safe and successful management of patients with an LVAD undergoing non-cardiac surgery. Understanding the basic physiology of preload dependency and afterload sensitivity in these patients is essential. The main considerations include a collaborative preoperative multidisciplinary approach, perioperative care aimed at optimizing the intravascular volume and right ventricular function, and maintaining the afterload within recommended ranges for optimal LVAD function.

Trends and predictors of intracranial hemorrhage in patients with advanced heart failure on left ventricular assist device from 2005 to 2014 in the United States

OBJECTIVES

Left ventricular assist devices are known to extend survival in patients with advanced heart failure; however, their association with intracranial hemorrhage is also well-known. We aimed to explore the risk trend and predictors of intracranial hemorrhage in patients with left ventricular assist devices.

MATERIAL AND METHODS

We included patients aged 18 years or older with left ventricular assist devices hospitalized in the US from 2005 to 2014 using the National Inpatient Sample. We computed the survey-weighted percentages with intracranial hemorrhage across the 10-year study period and assessed whether the proportions changed over time. Predictors of intracranial hemorrhage were evaluated using multivariable logistic regression model.

RESULTS

Of 33,246 hospitalizations, 568 (1.7%) had intracranial hemorrhage. The number of left ventricular assist devices placements increased from 873 in 2005 to 5175 in 2014. However, the risk of intracranial hemorrhage remained largely unchanged (1.7% to 2.3%; linear trend, P = 0.604). The adjusted odds of intracranial hemorrhage were increased with the presence of one of the following variables: female sex (odds ratio [OR], 1.58; 95% CI, 1.03-2.43), history of ischemic stroke (OR, 3.13; 95% CI, 1.86-5.28), or Charlson Comorbidity Index score of 3 or more (OR, 77.40; 95% CI, 10.03-597.60).

CONCLUSIONS

Over the last decade, the risk of intracranial hemorrhage has remained relatively unchanged despite an increase in the use of left ventricular assist devices in patients with advanced heart failure. Women, higher Charlson Comorbidity Index scores, and history of ischemic stroke were associated with higher odds of intracranial hemorrhage in patients with left ventricular assist devices.

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.

Preoperative atrial fibrillation predicts worse outcomes after LVAD implantation

Introduction: Left ventricular assist device (LVAD) implantation is a common therapy for end-stage heart failure. Heart failure patients often present with atrial fibrillation (AF). The purpose of this study was to evaluate the influence of preoperative AF as well as vascular complications on outcome in LVAD patients. Methods: Between 01/2010 and 12/2017, 168 patients (141 male) with end-stage heart failure underwent LVAD implantation at a single center. Patient outcome was retrospectively studied by using the Kaplan-Meier method for analyzing crude survival as well as Cox regression for analyzing risk factors. Results: Sixty-two patients suffered from preoperative atrial fibrillation at LVAD implantation. Mean age was 56.8±11.9 years (range: 22–79) and 141 (84%) were male. Postoperative vascular or visceral surgical management due to malperfusion was needed in 27 patients (16.1%) and did not correlate with postoperative mortality (P=0.121, HR=1.587, CI=0.885–2.845). Patients with preoperative AF had a worse outcome in the Kaplan-Meier analysis (P=0.069). In contrast, cox regression showed that postoperative AF could not to be considered to be an independent predictor of mortality in this study group. Conclusion: Our data suggest that preoperative AF may be a potential predictor of mortality and impaired long-term outcome in LVAD patients. In contrast, preoperative ECLS and vascular or visceral surgery after LVAD implantation did not represent limiting factors with regard to mortality after LVAD implantation.

Fixed-dose aspirin monotherapy compared with thromboelastography directed antiplatelet therapy in long-term management of left ventricular assist devices

BACKGROUND AND AIM

The role of thromboelastography (TEG) in managing antiplatelet therapy (APT) in left ventricular assist devices (LVADs) is controversial. Our aim was to determine whether removal of TEG from an LVAD-specific APT protocol reduced late-onset bleeding without increasing thromboembolic complications.

METHODS

We performed a single-center, retrospective cohort study including all recipients of a continuous-flow LVAD between April 2005 and November 2019 (n = 293). LVAD recipients before June 1, 2017 (n = 221) whose APT was monitored and adjusted using TEG were compared with LVAD recipients after June 1, 2017 (n = 72) where TEG was not utilized. Occurrence of late-onset bleeding events after postoperative Day 7 and thromboembolic events were collected. APT doses, warfarin use and International normalized ratio (INR) values were collected at discharge and at 1, 3, 6, and 12-months postimplantation.

RESULTS

Over a median 12-month follow-up, INTERMACS major bleeding events occurred in 35% of patients where TEG was utilized compared with 29% where TEG was not utilized (p = 0.375), and procedural intervention was required in 29% compared with 18%, respectively (p = 0.058). Use of TEG was associated with higher doses of aspirin (>325 mg) (41% compared with none) and use of a second antiplatelet (dipyridamole) (43% compared to 1%). Despite this, there was no significant difference in thromboembolic events (15% in each).

CONCLUSIONS

Our study suggests the use of TEG led to increased doses of aspirin as well as adding a second antiplatelet agent, without improving outcomes in LVAD recipients. Furthermore, the removal of TEG from an LVAD-specific APT protocol did not worsen thromboembolic outcomes.

Hyperadhesive von Willebrand Factor Promotes Extracellular Vesicle-Induced Angiogenesis: Implication for LVAD-Induced Bleeding

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VWF in patients on LVAD supports was hyperadhesive, activated platelets, and generated platelet-derived extracellular vesicles.

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Extracellular vesicles from LVAD patients and those from shear-activated platelets promoted aberrant angiogenesis in a VWF-dependent manner.

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The activated VWF exposed the A1 domain through the synergistic actions of oxidative stress and HSS generated in LVAD-driven circulation.

Bleeding associated with left ventricular assist device (LVAD) implantation has been attributed to the loss of large von Willebrand factor (VWF) multimers to excessive cleavage by ADAMTS-13, but this mechanism is not fully supported by the current evidence. We analyzed VWF reactivity in longitudinal samples from LVAD patients and studied normal VWF and platelets exposed to high shear stress to show that VWF became hyperadhesive in LVAD patients to induce platelet microvesiculation. Platelet microvesicles activated endothelial cells, induced vascular permeability, and promoted angiogenesis in a VWF-dependent manner. Our findings suggest that LVAD-driven high shear stress primarily activates VWF, rather than inducing cleavage in the majority of patients.

Biomarkers in Patients with Left Ventricular Assist Device: An Insight on Current Evidence

Left ventricular assist devices (LVADs) have been representing a cornerstone therapy for patients with end-stage heart failure during the last decades. However, their use induces several pathophysiological modifications which are partially responsible for the complications that typically characterize these patients, such as right ventricular failure, thromboembolic events, as well as bleedings. During the last years, biomarkers involved in the pathways of neurohormonal activation, myocardial injury, adverse remodeling, oxidative stress and systemic inflammation have raised attention. The search and analysis of potential biomarkers in LVAD patients could lead to the identification of a subset of patients with an increased risk of developing these adverse events. This could then promote a closer follow-up as well as therapeutic modifications. Furthermore, it might highlight some new therapeutic pharmacological targets that could lead to improved long-term survival. The aim of this review is to provide current evidence on the role of different biomarkers in patients with LVAD, in particular highlighting their possible implications in clinical practice.

Stroke epidemiology and outcomes in the modern era of left ventricular assist devices

The care for the patients with end-stage heart failure has been revolutionized by the introduction of durable left ventricular assist devices, providing a substantial improvement in patient survival and quality of life and an alternative to heart transplantation. The newest devices have lower instances of mechanical dysfunction and associated pump thrombosis. Despite these improvements in complications, the use of continuous flow assist devices is still associated with high rates of thrombotic and hemorrhagic complications, most notably stroke in approximately 10% of continuous flow assist devices patients per year. With the newest HeartMate 3 devices, there have been lower observed rates of stroke, which has in part been achieved by both improvements in pump technology and knowledge of the risk factors for stroke and neurological complications. The therapeutic options available to clinicians to reduce the risk of stroke, including management of hypertension and antithrombotics, will be reviewed in this manuscript.

Unfractionated and Low-Molecular-Weight Heparin for Bridging Patients with Left Ventricular Assist Device: An Event-Based Analysis

The relative efficacy of bridging with low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH) in left ventricular assist device (LVAD) patients has not been established. We performed a retrospective, longitudinal cohort study to evaluate safety and efficacy of bridging strategies including all adult LVAD patients implanted at the Medical University of South Carolina from August 2014 to July 2017. In addition to LMWH and UFH exposure, we recorded any time period a patient did not receive a bridging agent for a subtherapeutic international normalized ratio (INR) value as a control group; these events were defined as nonbridging (NB) events. Multivariable Cox regression survival models were utilized for analysis. There were 563 episodes evaluated in 50 patients. Compared with NB events, UFH (adjusted hazard ratio [aHR], 3.75; 95% CI, 1.45-9.73; p = 0.007) and LMWH (aHR, 2.25; 95% CI, 1.03-4.94; p = 0.043) were both associated with an increased risk of bleeding. Compared with NB events, LMWH was not associated with a decreased risk of clotting events (aHR, 1.56; 95% CI, 0.28-8.73; p = 0.616). In the 381 NB events, a nonsignificant signal was noted toward increased risk of thrombotic events in those with an INR ≤ 1.5 (aHR, 2.99; 95% CI, 0.57-15.8; p = 0.2). Among all 563 episodes, those with a baseline INR ≥ 2.0 demonstrated an increased risk of bleeding events (aHR, 2.35; 95% CI, 1.18-5.69; p = 0.016). Our data suggest that the efficacy of LMWH bridging in LVAD patients warrants further investigation.

Vascular procedures in patients with left ventricular assist devices: single-center experience

Objective

A growing number of patients suffering from heart failure is living with a left ventricular assist device (LVAD) and is in the need for non-cardiac surgery. Vascular procedures due to ischemia, bleeding, or other device-related complications may be required and pose a challenge to the caregivers in terms of monitoring and management of these patients. Therefore, we reviewed our experience with LVAD patients undergoing vascular surgery.

Methods

From January 2010 until March 2017, a total of 54 vascular procedures were performed on 41 LVAD patients at our institution. Patient records were reviewed retrospectively in terms of incidence of LVAD-related complications, including thrombosis, stroke, bleeding, wound healing, and survival associated with vascular surgery. The type of surgery was recorded, as well as various clinical demographic variables.

Results

Vascular procedures were performed in 35 men (85.4%) and 6 women (14.6%) with LVADs. There were no perioperative strokes, device thromboses, or device malfunctions. Thirty-day mortality overall was 26.8% (eleven patients), with most patients dying within 30 days after LVAD implantation due to multi-organ failure. In 25 procedures (46.3%), a blood transfusion was necessary.

Conclusion

Patients on LVAD support are a complex cohort with a high risk for perioperative complications. In a setting where device function and anticoagulation are monitored closely, vascular surgery in these patients is feasible with an acceptable perioperative risk.

Heart Failure Association of the European Society of Cardiology position paper on the management of left ventricular assist device-supported patients for the non-left ventricular assist device specialist healthcare provider: Part 2: at the emergency department

The improvement in left ventricular assist device (LVAD) technology and scarcity of donor hearts have increased dramatically the population of the LVAD‐supported patients and the probability of those patients to present to the emergency department with expected and non‐expected device‐related and patient–device interaction complications. The ageing of the LVAD‐supported patients, mainly those supported with the ‘destination therapy’ indication, increases the risk for those patients to suffer from other co‐morbidities common in the older population. In this second part of the trilogy on the management of LVAD‐supported patients for the non‐LVAD specialist healthcare provider, definitions and structured approach to the LVAD‐supported patient presenting to the emergency department with bleeding, neurological event, pump thrombosis, chest pain, syncope, and other events are presented. The very challenging issue of declaring death in an LVAD‐supported patient, as the circulation is artificially preserved by the device despite no other signs of life, is also discussed in detail.

Protein C Pathway, Inflammation, and Pump Thrombosis in Patients With Left Ventricular Assist Devices

Use of left ventricular assist devices (LVADs) for management of advanced heart failure is becoming increasingly common; however, device associated thrombosis remains an important cause of mortality in this patient population. We hypothesize that inflammation in LVAD implanted patients dysregulates the protein C pathway, creating a hypercoagulable state leading to thrombosis. Plasma samples from 22 patients implanted with the Thoratec HeartMate II LVAD were analyzed by commercial ELISAs. Retrospective sample selection included those collected 1-3 months prior to and within 1 month after a thrombotic or bleeding event. Unrelated to warfarin dosing, total protein S and free protein S (p = 0.033) levels were 20% lower in patients with LVAD-thrombosis than in patients with LVAD-bleeding. Levels of protein C, soluble endothelial cell protein C receptor, and soluble thrombomodulin were similar in both groups before and after the event. Compared to normal, C-reactive protein levels were 25-fold elevated in LVAD-thrombosis patients but only 9-fold elevated in LVAD-bleeding patients. This study suggests that protein S, influenced by the inflammatory state, is a gatekeeper for the function of protein C in patients with LVAD-associated thrombosis.

Cardiac Emergencies in Kids

Encountering a child with congenital heart disease after surgical palliation in the emergency department, specifically the single-ventricle or ventricular assist device, without a basic familiarity of these surgeries can be extremely anxiety provoking. Knowing what common conditions or complications may cause these children to visit the emergency department and how to stabilize will improve the chance for survival and is the premise for this article, regardless of practice setting.

Anticoagulation in Critically Ill Adults during Extracorporeal Circulation

Extracorporeal circuits including renal replacement therapy, extracorporeal membrane oxygenation, and ventricular assist devices are increasingly used in critically ill patients. The need for anticoagulation to provide circuit patency and avoid thrombosis remains a challenging task for treating physicians. In the presence of overall low scientific evidence concerning the optimal anticoagulants, monitoring tests, and therapeutic target ranges, recommendations are largely expert opinions and most centers use individual "in-house" anticoagulation protocols. This review gives a practical view on current concepts of anticoagulation strategies in patients with extracorporeal assist devices.

A Comprehensive Review of Risk Factor, Mechanism, and Management of Left Ventricular Assist Device-Associated Stroke

The use of left ventricular assist devices (LVADs) has been increasing in the last decade, along with the number of patients with advanced heart failure refractory to medical therapy. Ischemic stroke and intracranial hemorrhage remain the leading causes of morbidity and mortality in LVAD patients. Despite the common occurrence and the significant outcome impact, underlying mechanisms and management strategies of stroke in LVAD patients are controversial. In this article, we review our current knowledge on pathophysiology and risk factors of LVAD-associated stroke, outline the diagnostic approach, and discuss treatment strategies.

Antithrombotic Therapy for Stroke Patients with Cardiovascular Disease

Prevention of ischemic stroke relies on the use of antithrombotic medications comprising antiplatelet agents and anticoagulation. Stroke risk is particularly high in patients with cardiovascular disease. This review will focus on the role of antithrombotic therapies in the context of different types of cardiovascular disease. We will discuss oral antiplatelet medications and both IV and parental anticoagulants. Different kinds of cardiovascular disease contribute to stroke via distinct pathophysiological mechanisms, and the optimal treatment for each varies accordingly. We will explore the mechanism of stroke and evidence for antithrombotic therapy in the following conditions: atrial fibrillation, prosthetic heart values (mechanical and bioprosthetic), aortic arch atherosclerosis, congestive heart failure (CHF), endocarditis (infective and nonbacterial thrombotic endocarditis), patent foramen ovale (PFO), left ventricular assist devices (LVAD), and extracorporeal membrane oxygenation (ECMO). While robust data exist for antithrombotic use in conditions such as atrial fibrillation, optimal treatment in many situations remains under active investigation.

Comparison of Outcomes of Enoxaparin Bridge Therapy in HeartMate II versus HeartWare HVAD Recipients

BACKGROUND

There is a lack of robust data evaluating outcomes of enoxaparin "bridge" therapy in left ventricular assist device (LVAD) patients.

METHODS

We performed a retrospective study of HeartMate II (HM II) and HeartWare HVAD recipients that received therapeutic enoxaparin as "bridge" therapy to describe bleeding and thrombotic events and compare outcomes between devices. The primary endpoint was the incidence of bleeding within 30 days of "bridge" episode. Major bleeding was defined by INTERMACS criteria.

RESULTS

We evaluated 257 "bridge" episodes in 54 patients, 35 with a HM II device and 19 with an HVAD device that underwent 176 and 81 bridging episodes, respectively. The median INR prior to "bridge" was lower in the HM II group compared to the HVAD group (1.5 vs 1.7, P < .01), however, there was no difference in the median duration of "bridge" therapy (7 vs 7 days, P = .42). There were a total of 30 (12%) bleeding episodes, with the majority in the HM II group vs HVAD (26 [15%] vs 4 [5%], P = .02). We observed 3 (1%) thromboembolic events in 2 (4%) patients with an HVAD device. On multivariate analysis, the presence of a HM II device was associated with a 4-fold increased risk of bleeding.

CONCLUSION

We found the use of enoxaparin "bridge" therapy to be associated with a higher incidence of bleeding in patients with a HM II device compared with an HVAD device. Assessment of device- and patient-specific factors should be evaluated to minimize bleeding events.

Benefit of Self-Managed Anticoagulation in Patients with Left Ventricular Assist Device

BACKGROUND

 The exact monitoring of the therapeutic-range international normalized ratio (INR) after left ventricular assist device (LVAD) implantation is an important aim to reduce the risk of thrombosis or bleeding complications. Service providers offer a telemedical anticoagulation service (CS).

METHODS

 We compared LVAD patients using the CS (n = 15) to those who received regular medical care (RMC; n = 15) to investigate if telemedicine supervision increased the INR-specific time in the therapeutic range (TTR) during anticoagulation. All patients received self-management training for phenprocoumon medication according to their INR value. INR values were documented for 12 months. A survey (scale: 1 = not satisfied and 10 = very satisfied) was used to determine patient's satisfaction and psychological well-being.

RESULTS

 A total of 1,798 INR measurements were analyzed. The TTR_Rosendaal was higher in patients undergoing RMC (78.1 ± 14.3%) compared with that in patients using the CS (58.3 ± 28.0%, p = 0.03). The patient's satisfaction with the coagulation setting at the beginning of the study (RMC: 6.7 ± 3.1, CS: 7.2 ± 3.0, p = 0.74) and psychological wellbeing (RMC: 6.5 ± 1.9, CS: 6.5 ± 2.7, p = 0.97) were comparable between both groups.

CONCLUSION

 We found that INR self-management is superior regarding the efficiency of post-LVAD anticoagulation therapy when compared with telemedical (CS)-based INR management in a small study cohort. Intensive training by experienced staff was able to replace CS.

Management of Stroke in Patients with Left Ventricular Assist Devices

INTRODUCTION

The number of patients with left ventricular assist devices (LVAD) is rapidly growing in industrialized countries. While cerebrovascular events comprise a significant complication, data on stroke etiology, clinical management and functional outcome are scarce.

METHODS

Consecutive LVAD patients with ischemic or hemorrhagic stroke receiving treatment at an university stroke center between 2010 and 2018 were included into an institutional registry. Clinical characteristics, causes, management and functional outcome of stroke occurring within this cohort are reported. Acceptable functional outcome was defined as mRS 0-3.

RESULTS

N = 30 acute strokes occurred in 20 patients (77% ischemic, 23% hemorrhagic, mean age 57 ± 13 years, 10% female, 8 patients (40%) had more than one event). 87% of all events happened with non-pulsatile devices, on average 9 (IQR 3-22) months after the implantation. All patients used oral anticoagulation with a Vitamin-K antagonist in combination with anti-platelets. The international normalized ratio (INR)-values were outside the therapeutic range in 39% of ischemic strokes and in 57% of hemorrhagic strokes. Ischemic strokes were predominantly of cardioembolic origin (92%) and of mild to moderate clinical severity (median NIHSS 6 (IQR 4-10). None qualified to receive intravenous thrombolysis or intra-arterial endovascular therapy. 61% of IS-patients showed an acceptable functional outcome after three months. 4/7 patients with hemorrhagic stroke received immediate reversal of anticoagulation without any thrombotic complications.

CONCLUSION

The majority of LVAD patients with ischemic stroke had an acceptable functional outcome after three months. Future clinical research is warranted to improve therapeutic strategies for acute care and stroke prevention.

Insight into Atrial Fibrillation in LVAD Patients: From Clinical Implications to Prognosis

The use of left ventricular assist devices (LVADs), whether for destination therapy or bridge to transplantation, has gained increasing validation in recent years in patients with advanced heart failure. Arrhythmias can be the most challenging variables in the management of such patients but the main attention has always been focused on ventricular arrhythmias given the detrimental impact on mortality. Nevertheless, atrial fibrillation (AF) is the most common rhythm disorder associated with advanced heart failure and may therefore characterize the LVADs' pre- and postimplantation periods. Indeed, the consequences of AF in the population suffering from standard heart failure may require a more comprehensive evaluation in the presence of or in sight of an LVAD, making the AF clinical management in these patients potentially complex. Several studies have been based on this subject with different and often conflicting results, leaving many questions unresolved. The purpose of this review is to summarize the main pieces of evidence about the clinical impact of AF in LVAD patients, underlining the main implications in terms of hemodynamics, thromboembolic risk, bleeding and prognosis. Therapeutic considerations about the clinical management of these patients are also made according to the latest evidence.

Baseline Thromboelastogram as a Predictor of Left Ventricular Assist Device Thrombosis

Left ventricular assist device (LVAD) pump thrombosis occurs in up to 8.4% of patients within 3-months postimplantation. Thromboelastography (TEG) could be used to signal hypercoagulability at LVAD implantation to predict patients at high risk for thrombosis. We sought to evaluate whether TEG maximum amplitude (MA) hypercoagulability (MA ≥69 mm) at the time of LVAD implantation predicts pump thrombosis. A single center, retrospective, nested case-control study was conducted using patients from January 1, 2005, to March 31, 2015. Each pump thrombosis case was matched to two control subjects based on age ± 5 years, sex, and duration of follow-up. A multivariable logistic regression analysis was performed on the matched sets; the odds ratio with 95% confidence interval (CI) was calculated to estimate the relative risk. Thirty-seven age- and sex-matched case-control sets were included for a total of 111 study participants. TEG-MA hypercoagulability occurred in 10.8% of the case group versus 6.8% of controls. There was no association between TEG-MA hypercoagulability and device thrombosis (odds ratio 1.71, 95% confidence interval 0.42-7.05, p = 0.46). Utilization of baseline TEG-MA hypercoagulability to detect individuals at risk for LVAD thrombosis is a novel concept. This study found no significant association between TEG-MA and LVAD thrombosis.

Telecardiographic measurements for device migration: A useful tool for follow-up

OBJECTIVE

Pump thrombosis in left ventricular assist device (LVAD) patients is an important cause of mortality and morbidity. Inflow cannula migration is a predisposing factor for pump thrombosis. Telecardiographic measurements can be used to follow up apical cannula deviation. In this study, we aimed to evaluate the migration of the inflow cannulas in patients with LVADs using angle measurements on telecardiograms.

METHODS

Twenty-three patients who were implanted left ventricular assist devices in our clinic between February 2013 and April 2016 were included in our study. During the first year of follow-up, changes in angle measurements on postoperative 1^st, 3^rd, 6^th, and 12^th month telecardiograms were compared against the incidence of device thrombus and serum Lactate Dehydrogenase (LDH) levels.

RESULTS

Patients who were diagnosed with device thrombosis had more change in inflow cannula angles than patients without device thrombus (p<0.05 at 6^th and 12^th months). Patients with higher LDH values had more parallel angular changes at all intervals, and the change in angle was statistically significant at 3^rd, 6^th and 12^th months (p<0.05).

CONCLUSION

This study shows that it is possible to track the migration of inflow cannulas in patients with left ventricular heart failure using telecardiograms. The correlation between angle change and LDH levels and embolic events may suggest that telecardiographic follow up of angles may be a useful tool for ventricular assist devices teams for early detection of thrombus.

Outcome of mechanical circulatory support at the University Medical Centre Utrecht

Background

The prevalence of heart failure (HF) is increasing substantially and, despite improvements in medical therapy, HF still carries a poor prognosis. Mechanical circulatory support (MCS) by a continuous-flow left ventricular assist device (cf-LVAD) improves survival and quality of life in selected patients. This holds especially for the short-term outcome, but experience regarding long-term outcome is growing as the waiting time for heart transplantation is increasing due to the shortage of donor hearts. Here we present our results from the University Medical Centre Utrecht.

Methods

Data of all patients with a cf-LVAD implant between March 2006 and January 2018 were collected. The primary outcome was survival. Secondary outcomes included adverse events defined according to the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) definitions, described per patient year.

Results

A total of 268 patients (69% male, mean age 50 ± 13 years) received a cf-LVAD. After a median follow-up of 542 (interquartile range 205–1044) days, heart transplantation had been performed in 82 (31%) patients, the cf-LVAD had been explanted in 8 (3%) and 71 (26%) had died. Survival at 1, 3 and 5 years was 83%, 72% and 57%, respectively, with heart transplantation, cf-LVAD explantation or death as the end-point. Death was most often caused by neurological complications (31%) or infection (20%). Major bleeding occurred 0.51 times and stroke 0.15 times per patient year.

Conclusion

Not only short-term results but also 5‑year survival after cf-LVAD support demonstrate that MCS is a promising therapy as an extended bridge to heart transplantation. However, the incidence of several major complications still has to be addressed.

Electronic supplementary material

The online version of this article (10.1007/s12471-020-01375-4) contains supplementary material, which is available to authorized users.

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.

Magnetically Active Cardiac Patches as an Untethered, Non-Blood Contacting Ventricular Assist Device

Patients suffering from heart failure often require circulatory support using ventricular assist devices (VADs). However, most existing VADs provide nonpulsatile flow, involve direct contact between the blood flow and the device's lumen and moving components, and require a driveline to connect to an external power source. These design features often lead to complications such as gastrointestinal bleeding, device thrombosis, and driveline infections. Here, a concept of magnetically active cardiac patches (MACPs) that can potentially function as non-blood contacting, untethered pulsatile VADs inside a magnetic actuationsystem is reported. The MACPs, which are composed of permanent magnets and 3D-printed patches, are attached to the epicardial surfaces, thus avoiding direct contact with the blood flow. They provide powerful actuation assisting native heart pumping inside a magnetic actuation system. In ex vivo experiments on a healthy pig's heart, it is shown that the ventricular ejection fractions are as high as 37% in the left ventricle and 63% in the right ventricle. Non-blood contacting, untethered VADs can eliminate the risk of serious complications associated with existing devices, and provide an alternative solution for myocardial training and therapy for patients with heart failure.

Hemostatic complications associated with ventricular assist devices

Hemostatic complications are common in patients with ventricular assist devices. The pathophysiologic mechanisms that lead to dysregulated hemostasis involve complex interactions between device surface, sheer stress, and blood flow. These factors lead to various manifestations that require a thorough understanding of the interplay among platelets, coagulation factors, and red cells. In this article, we review the pathophysiology of hematologic complications (bleeding, acquired von Willebrand disease, heparin-induced thrombocytopenia, hemolysis, stroke and pump thrombosis), the clinical manifestations, and the management of each. We summarize the evidence available for management of these entities and provide a pragmatic clinical review.

Early signatures of bleeding and mortality in patients on left ventricular assist device support: novel methods for personalized risk-stratification

Background: Left ventricular assist devices (LVADs) provide support for patients with end-stage heart failure. The aims of this study were to determine whether baseline analysis and early trends in routine laboratory data, platelet activity, and thromboinflammatory biomarkers following LVAD implantation reveal trends that predict personalized risks of one-year gastrointestinal (GI) bleeding, stroke, pump thrombosis, drive-line infections and mortality in patients on LVAD support. Methods: We performed an observational study at the University of Kentucky with 61 participants who underwent first-time LVAD implantation. Blood was collected at baseline and post-op days 0, 1, 3 and 6 as well as clinical follow-up. Demographics, clinical characteristics, one-year adverse events and routine laboratory data were collected from electronic medical records. Platelet function and plasma biomarkers were profiled. Results: Evaluation of routine laboratory results revealed that sustained thrombocytopenia and increased mean platelet volume (MPV) were associated with development of GI bleeding and mortality. Platelet function at follow-up visit predicted one-year bleeding events. Thrombotic biomarker sCD40L strongly predicted one-year GI bleeding at baseline before implantation and within the first week following LVAD implant. Conclusions: Early trends in routine bloodwork and platelet function may serve as novel signatures of patients at risk to experience adverse events.

Evaluation of anticoagulation and nonsurgical major bleeding in recipients of continuous-flow left ventricular assist devices

Continuous-flow left ventricular assist device (LVAD) placement has become a standard of care in advanced heart failure treatment. Bleeding is the most frequently reported adverse event after LVAD implantation and may be increased by antithrombotic agents used for prevention of pump thrombosis. This retrospective cohort included 85 adult patients implanted with a Heartmate II LVAD. Major bleeding was defined as occurring >7 days after implant and included intracranial hemorrhage, events requiring 2 units of packed red blood cells within a 24-h period, and death from bleeding. Primary outcome was intensity of anticoagulation between patients with or without at least one incidence of nonsurgical major bleeding. Major bleeding occurred in 35 (41%) patients with 0.48 events per patient year and a median (IQR) time to first bleed of 134.5 (39.3, 368.5) days. The median (IQR) INR at time of bleed was 1.7 (1.4, 2.5). Median INR during follow-up did not differ between groups and patients with major bleeding were not more likely to have a supra-therapeutic INR. Patients who bled were more likely to have received LVAD for destination therapy, to have lower weight, worse renal function, and lower hemoglobin at baseline. Duration of LVAD support and survival were similar between groups with no difference in occurrence of thrombosis. Incidence of nonsurgical major bleeding was not significantly associated with degree of anticoagulation. Certain baseline characteristics may be more important than anticoagulation intensity to identify patients at risk for bleeding after LVAD implant. Modification of anticoagulation alone is not a sufficient management strategy and early intervention may be required to mitigate bleeding impact.

Development of an Outpatient Guideline for Optimal Anticoagulation Bridging in Patients With Durable Mechanical Circulatory Support

Patients with durable mechanical circulatory support are at increased risk of thromboembolic and bleeding complications. Current guidelines recommend that these patients receive chronic anticoagulation with warfarin to maintain a target international normalized ratio (INR) as specified by device manufacturers. Limited data exist regarding management of subtherapeutic INRs in this setting. To standardize clinical practice at our institution, we assembled a multidisciplinary task force including members from various specialties to develop a guideline for managing subtherapeutic INRs that incorporates published data and expert opinion. In this article, we present our clinical practice guideline as a decision support tool to aid clinicians in developing a consistent strategy for managing subtherapeutic INRs and for safely bridging anticoagulation in patients receiving mechanical circulatory support.

Facilitating noncardiac surgery for the patient with left ventricular assist device: A guide for the anesthesiologist

The introduction of left ventricular assist device (LVAD) has improved survival rates for patients with end-stage heart failure. Two categories of VADs exist: one generates pulsatile flow and the other produces nonpulsatile continuous flow. Survival is better for patients with continuous-flow LVADs. With improved survival, more of such patients now present for noncardiac surgery (NCS). This review, written for the general anesthesiologists, addresses the perioperative considerations when the patient undergoes NCS. For best outcomes, a multidisciplinary approach is essential in perioperative management of the patient.

Anticoagulation management following left ventricular assist device implantation is similar across all provider strategies

OBJECTIVES

Thromboembolic and bleeding events are potential complications following left ventricular assist device implantation. A tight control of the international normalized ratio (INR) is believed to be crucial in the reduction of postimplant complications. There is significant variability among institutions as to whether a device implanting centre should be managing the INR. In this study, we evaluated the effect of INR management strategies in maintaining a therapeutic INR.

METHODS

A retrospective review was utilized to identify patients implanted with either the HeartMate II or the HeartWare HVAD between January 2011 and February 2016. Patients were stratified into 4 groups based on the post-discharge INR management strategy: outside hospital system anticoagulation clinic, outside hospital primary care provider, implanting centre anticoagulation clinic or implanting centre ventricular assist device office. The INR data were collected and analysed for both the early (discharge, 7, 14, 21 and 30 days) and late (3, 6, 9 and 12 months) postoperative periods.

RESULTS

There were 163 patients identified during the study period who met the study inclusion criteria: 49 (30%) patients were managed by an outside hospital system anticoagulation clinic, 59 (36.2%) patients by an outside hospital physician/primary care provider, 22 (13.5%) patients by the implanting centre anticoagulation clinic and 33 (20.2%) patients by the implanting centre ventricular assist device office. There were no statistically significant differences found between management strategies across all time points.

CONCLUSIONS

There was no statistically significant difference found between the management strategies examined. Regardless of the chosen INR management strategy, patients have similar INR values and postoperative outcomes.

Left Ventricular Assist Devices: How Do We Define Success?

Despite the growing acceptance of left ventricular assist device (LVAD) therapy to improve survival and quality of life in heart failure (HF) patients, uncertainties persist regarding the definition of a successful implant. We sought to define an innovative approach to assess success and subsequently compare preoperative variables affecting outcomes. From January 2007 to 2015, 278 patients underwent LVAD implantation. Median age at implant was 62 years and 81% patients were males. Indication for support was bridge-to-transplantation in 36% patients and the etiology of HF was ischemic in 49% patients. Based on clinically relevant and accepted standards, we defined successful LVAD implant as someone who was alive or transplanted at 2 years, had two or less readmissions in the first year, had no major adverse events in the first year, and had a New York Heart Association class of ≤ II at 6 months. Follow-up was obtained for a median of 1.7 years for a total of 605 patient-years-of-support. Based on our criteria, 81/278 (29%) patients were defined as having a successful implant. Univariate predictors of LVAD failure included destination therapy indication (hazard ratio [HR] = 2.11 [1.24, 3.58]), ischemic cardiomyopathy (HR = 1.73 [1.02, 2.94]), and a higher left ventricular ejection fraction (HR = 1.54 [1.07, 2.22]). After multivariable analysis, only destination therapy indication (HR = 2.2 [1.28, 3.78]) was found to be independently predictive of success failure. Despite an overall trend toward improved outcomes on device therapy, our criteria classified only one-third of patients as successful. Continued improvements in adverse event profiles, appropriate patient selection, and optimal time of implantation, together hold the key to improve outcomes after LVAD therapy.

Antithrombotic Strategies and Device Thrombosis

Despite improvements in left ventricular assist device (LVAD) technology, bleeding and thrombotic complications are major concerns that adversely influence morbidity and mortality. Current antithrombotic therapy recommendations for LVAD thrombosis prophylaxis are largely derived from clinical device trials that implement a one-size-fits-all strategy. Objective serial laboratory-based assessment of thrombogenicity is needed to balance the risk of bleeding and thrombotic complications. Finally, the newest-generation device, the HeartMate 3, has been associated with lower levels of shear and reduced hemolysis that may mitigate thrombotic event occurrences.

Discontinuation of anticoagulant therapy for a month in a patient with HeartMate III continuous-flow left ventricular assist device without thromboembolic events

The recommended anticoagulation regimen for continuous-flow left ventricular assist device (LVAD) systems is warfarin and aspirin with a targeted international normalized ratio (INR) of 2.0-3.0. Our patient is a 58-year-old male who underwent surgical HeartMate III continuous-flow LVAD implantation 3 months ago outside the country. The patient mistakenly stopped taking warfarin for 1 month prior to presenting to our center for a routine visit. Luckily, the patient was doing very well without any complication despite the fact that his INR was 1.0.

Effects of vitamin K epoxide reductase complex 1 gene polymorphisms on warfarin control in Japanese patients with left ventricular assist devices (LVAD)

PURPOSE

This study aimed to investigate relationships between times in therapeutic range (TTR) or warfarin sensitivity indexes (WSI) and VKORC1-1639G>A and CYP2C9 polymorphisms in patients with left ventricular assist devices (LVAD).

METHODS

Severe heart failure patients who received LVAD from January 1, 2013 to October 31, 2017 were recruited. Relationships between TTR or WSI and VKORC1-1639G>A and CYP2C9 gene polymorphisms were investigated immediately after LVAD implantation (period 1) and immediately prior to hospital discharge (period 2).

RESULTS

Among 54 patients, 31 (72.1%) had VKORC1-1639AA and CYP2C9*1/*1 (AA group) polymorphisms and 12 (27.9%) had VKORC1-1639GA and CYP2C9*1/*1 (GA group) polymorphisms. During period 1, mean prothrombin time-international normalized ratio (PT-INR) values were significantly higher in the AA group than in the GA group (2.21 vs. 2.05, p < 0.0001). Mean WSI values were 1.68-fold greater in the AA group than in the GA group (1.14 vs. 0.68, p < 0.0001). In addition, times below the therapeutic range (TBTR) in the GA group were significantly greater than in the AA group during period 1 (39.8 vs. 28.3%, p = 0.032), and insufficient PT-INR was more frequent in the GA group than in the AA group. However, mean PT-INR values during period 2 did not differ and no significant differences in TTR, TATR, and TBTR values were identified. In subsequent multivariable logistic regression analyses, the VKORC1-1639GA allele was significantly associated with insufficient anticoagulation.

CONCLUSION

Patients with the VKORC1-1639GA and CYP2C9*1/*1 alleles may receive insufficient anticoagulation therapy during the early stages after implantation of LVAD, and VKORC1-1639G>A and CYP2C9 genotyping may contribute to more appropriate anticoagulant therapy after implantation of LVAD.

Anticoagulation Control in Patients With Ventricular Assist Devices

Anticoagulation control has been associated with risk of thromboembolism and hemorrhage. Herein, we explore the relationship between anticoagulation control achieved in left ventricular assist device (LVAD) patients and evaluate the association with risk of thromboembolism and hemorrhage. Patients (19 years old or older) with a continuous flow LVAD placed from 2006 to 2012. Percent time spent in target range (PTTR) for international normalized ratio (INR) was estimated with target range of 2.0-3.0. Proportion of time spent in target range was categorized into PTTR > 60%, PTTR ≥ 50 < 60%, and PTTR < 50%. The relationship between PTTR and thromboembolism and hemorrhage was assessed. One hundred fifteen participants contributed 624.5 months of follow-up time. Only 20% of patients achieved anticoagulation control (PTTR > 60% for INR range of 2-3). After adjusting for chronic kidney disease, history of diabetes, history of atrial fibrillation, and age at implant, compared with patients with PTTR < 50%, the relative risk of thromboembolism in patients with PTTR ≥ 60% (hazard ratio [HR]: 0.37; 95% confidence interval [CI]: 0.14-0.96; p = 0.042) was significantly lower, but not for patients with a PTTR of ≥ 50 < 60% (HR: 0.21; 95% CI: 0.02-1.82; p = 0.16). The relative risk for hemorrhage was also significantly lower among patients with a PTTR ≥ 60% (HR: 0.45; 95% CI: 0.21-0.98; p = 0.045), but not among those with PTTR of ≥ 50 < 60% (HR: 0.47; 95% CI: 0.14-1.56; p = 0.22). This current study demonstrates that LVAD patients remain in the INR target range an average of 42.9% of the time. To our knowledge, this is the first report with regard to anticoagulation control as assessed by PTTR and its association with thromboembolism, hemorrhage, or death among patients with ventricular assist devices (VADs).