Heartmate 3 fully magnetically levitated left ventricular assist device for the treatment of advanced heart failure -1 year results from the Ce mark trial

Fully magnetically centrifugal left ventricular assist device and long-term outcomes: the ELEVATE registry

BACKGROUND AND AIMS

HeartMate 3 (HM3) is a fully magnetically levitated continuous flow left ventricular assist device, which received CE marking in 2015. The ELEVATE Registry was initiated to collect real-world outcomes in patients treated with HM3 post-CE Mark approval.

METHODS

A total of 540 subjects implanted at 26 centres between March 2015 and February 2017 were included in this registry. Of these, 463 received the device as a primary implant (primary implant cohort, PIC), 19 as a pump exchange (pump exchange cohort), and in 58 patients, only anonymized survival data were collected (anonymized cohort, AC). Patients in the PIC contributed to the baseline demographics, survival, adverse events, quality of life (QoL) (EuroQoL-5 Dimensions-5 Levels visual analogue scale), and functional capacity (6 min walk distance) assessments, while patients in the AC contributed only to survival.

RESULTS

Primary implant cohort patients had a mean age of 56 years and were predominantly male (89%) with 48% ischaemic aetiology. The majority of subjects was designated bridge to transplant (66%) and had INTERMACS Profiles 1-3 (70%). At baseline, the subjects had poor functional capacity (104 ± 140 m) and impaired QoL (35 ± 19 points). The overall survival rate of the PIC was 63.3% and survival free of stroke was 58.1% at 5 years. Significant improvements in functional capacity and QoL were observed and maintained for 5 years (301 ± 131 m and 64 ± 20 points, respectively).

CONCLUSIONS

Real-world data from the ELEVATE registry demonstrate an overall survival rate for primary implants of 63.3%. In the PIC, reductions in adverse events for patients in the extended follow-up and improved QoL and functional capacity were observed at 5 years in this patient population with advanced heart failure.

Mitigation effect of cell exclusion on blood damage in spiral groove bearings

Cell exclusion in spiral groove bearing (SGB) excludes red blood cells from high shear regions in the bearing gaps and potentially reduce haemolysis in rotary blood pumps. However, this mechanobiological phenomenon has been observed in ultra-low blood haematocrit only, whether it can mitigate blood damage in a clinically-relevant blood haematocrit remains unknown. This study examined whether cell exclusion in a SGB alters haemolysis and/or high-molecular-weight von Willebrand factor (HMW vWF) multimer degradation. Citrated human blood was adjusted to 35 % haematocrit and exposed to a SGB (n = 6) and grooveless disc (n = 3, as a non-cell exclusion control) incorporated into a custom-built Couette test rig operating at 2000RPM for an hour; shearing gaps were 20, 30, and 40 μm. Haemolysis was assessed via spectrophotometry and HMW vWF multimer degradation was detected with gel electrophoresis and immunoblotting. Haemolysis caused by the SGB at gaps of 20, 30 and 40 μm were 10.6 ± 3.3, 9.6 ± 2.7 and 10.5 ± 3.9 mg/dL.hr compared to 23.3 ± 2.6, 12.8 ± 3.2, 9.8 ± 1.8 mg/dL.hr by grooveless disc. At the same shearing gap of 20 µm, there was a significant reduced in haemolysis (P = 0.0001) and better preserved in HMW vWF multimers (p < 0.05) when compared SGB to grooveless disc. The reduction in blood damage in the SGB compared to grooveless disc is indicative of cell exclusion occurred at the gap of 20 µm. This is the first experimental study to demonstrate that cell exclusion in a SGB mitigates the shear-induced blood damage in a clinically-relevant blood haematocrit of 35 %, which can be potentially utilised in future blood pump design.

Innovative experimental animal models for real-time comparison of antithrombogenicity between two oxygenators using dual extracorporeal circulation circuits and indocyanine green fluorescence imaging

BACKGROUND

Antithrombogenicity of extracorporeal membrane oxygenation (ECMO) devices, particularly oxygenators, is a current problem, with numerous studies and developments underway. However, there has been limited progress in developing methods to accurately compare the antithrombogenicity of oxygenators. Animal experiments are commonly conducted to evaluate the antithrombogenicity of devices; however, it is challenging to maintain a steady experimental environment. We propose an innovative experimental animal model to evaluate different devices in a constant experimental environment in real-time.

METHODS

This model uses two venous-arterial ECMO circuits attached to one animal (one by jugular vein and carotid artery, one by femoral vein and artery) and real-time assessment of thrombus formation in the oxygenator by indocyanine green (ICG) fluorescence imaging. Comparison studies were conducted using three pigs: one to compare different oxygenators (MERA vs. CAPIOX) (Case 1), and two to compare antithrombotic properties of the oxygenator (QUADROX) when used under different hydrodynamic conditions (continuous flow vs. pulsatile flow) (Cases 2 and 3).

RESULTS

Thrombi, visualized using ICG imaging, appeared as black dots on a white background in each oxygenator. In Case 1, differences in the site of thrombus formation and rate of thrombus growth were observed in real-time in two oxygenators. In Case 2 and 3, the thrombus region was smaller in pulsatile than in continuous conditions.

CONCLUSIONS

We devised an innovative experimental animal model for comparison of antithrombogenicity in ECMO circuits. This model enabled simultaneous evaluation of two different ECMO circuits under the same biological conditions and reduced the number of sacrificed experimental animals.

2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure" replaces the "2013 ACCF/AHA Guideline for the Management of Heart Failure" and the "2017 ACC/AHA/HFSA Focused Update of the 2013 ACCF/AHA Guideline for the Management of Heart Failure." The 2022 guideline is intended to provide patient-centric recommendations for clinicians to prevent, diagnose, and manage patients with heart failure.

METHODS

A comprehensive literature search was conducted from May 2020 to December 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from MEDLINE (PubMed), EMBASE, the Cochrane Collaboration, the Agency for Healthcare Research and Quality, and other relevant databases. Additional relevant clinical trials and research studies, published through September 2021, were also considered. This guideline was harmonized with other American Heart Association/American College of Cardiology guidelines published through December 2021. Structure: Heart failure remains a leading cause of morbidity and mortality globally. The 2022 heart failure guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with heart failure, with the intent to improve quality of care and align with patients' interests. Many recommendations from the earlier heart failure guidelines have been updated with new evidence, and new recommendations have been created when supported by published data. Value statements are provided for certain treatments with high-quality published economic analyses.

Six-month outcomes in postapproval HeartMate3 patients: A single-center US experience

BACKGROUND

The European CE Mark approval study and the MOMENTUM 3 trial demonstrated safety and a reduction in hemocompatibility-related adverse events with the use of HeartMate 3 (HM3) device. This single-center study investigated the real-world experience in HM3 patients since FDA approval.

METHODS

This retrospective, observational study included patients implanted with the HM3 LVAD as a primary implant between October 2017 and March 2020. Patients were divided into trial group and postapproval group. The primary endpoint was survival at 6 months. Secondary endpoints were adverse events including pump thrombosis (requiring pump exchange), stroke, renal failure, acute limb ischemia, re-exploratory for bleeding, gastrointestinal bleeding, right ventricular failure, and driveline infection.

RESULTS

A total of 189 patients were implanted with HM3 device during the study period. 174 patients met the inclusion criteria: 82 patients in the trial group and 92 patients in the postapproval group. The postapproval group had younger patients, higher preoperative mean international normalized ratio, and greater numbers of patients with bridge to transplant (BTT) indications, IINTERMACS profile 1, and use of mechanical assist devices (other than IABP) than the trial group. Other characteristics between the two groups were comparable. Overall survival at 6 months in the postapproval group was 93.3% versus 93.8% (p = .88). The postapproval group demonstrated a statistically significant lower incidence of re-explorative surgery for bleeding (10.9% vs. 46.3, p = .01) than the trial group.

CONCLUSION

In this single-center study, the real-world 6-month survival in the postapproval group was comparable to the trial results. Further studies are needed to monitor long-term outcomes.

2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure

AIM

The "2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure" replaces the "2013 ACCF/AHA Guideline for the Management of Heart Failure" and the "2017 ACC/AHA/HFSA Focused Update of the 2013 ACCF/AHA Guideline for the Management of Heart Failure." The 2022 guideline is intended to provide patient-centric recommendations for clinicians to prevent, diagnose, and manage patients with heart failure.

METHODS

A comprehensive literature search was conducted from May 2020 to December 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from MEDLINE (PubMed), EMBASE, the Cochrane Collaboration, the Agency for Healthcare Research and Quality, and other relevant databases. Additional relevant clinical trials and research studies, published through September 2021, were also considered. This guideline was harmonized with other American Heart Association/American College of Cardiology guidelines published through December 2021.

STRUCTURE

Heart failure remains a leading cause of morbidity and mortality globally. The 2022 heart failure guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with heart failure, with the intent to improve quality of care and align with patients' interests. Many recommendations from the earlier heart failure guidelines have been updated with new evidence, and new recommendations have been created when supported by published data. Value statements are provided for certain treatments with high-quality published economic analyses.

A Comprehensive Review of Mechanical Circulatory Support Devices

Treatment strategies to combat cardiogenic shock (CS) have remained stagnant over the past decade. Mortality rates among patients who suffer CS after acute myocardial infarction (AMI) remain high at 50%. Mechanical circulatory support (MCS) devices have evolved as novel treatment strategies to restore systemic perfusion to allow cardiac recovery in the short term, or as durable support devices in refractory heart failure in the long term. Haemodynamic parameters derived from right heart catheterization assist in the selection of an appropriate MCS device and escalation of mechanical support where needed. Evidence favouring the use of one MCS device over another is scant. An intra-aortic balloon pump is the most commonly used short-term MCS device, despite providing only modest haemodynamic support. Impella CP® has been increasingly used for CS in recent times and remains an important focus of research for patients with AMI-CS. Among durable devices, Heartmate® 3 is the most widely used in the USA. Adequately powered randomized controlled trials are needed to compare these MCS devices and to guide the operator for their use in CS. This article provides a brief overview of the types of currently available MCS devices and the indications for their use.

Impact of third-generation left ventricular assist devices on quality of life: Scoping review and meta-analysis

OBJECTIVES

Development in device technology and the scarcity of donor's hearts have increased the number of patients with advanced heart failure receiving durable left ventricular assist devices (LVADs) as a bridge to transplantation and destination therapy, with improved prognosis compared with guideline-directed medical therapy. We sought to examine the impact of modern durable LVADs on the quality of life (QoL) of the recipients.

METHODS

We carried out a systematic review of articles on QoL following the implantation of third-generation LVADs published between January 2010 and February 2021. Included studies were critically analyzed and evidence synthesis was carried out into a meta-analysis.

RESULTS

The systematic search yielded 269 articles, 11 of which met the search predefined criteria. Three of them reported results of randomized trials and eight were retrospective and registry studies. Statistically significant QoL improvement from baseline was observed in all published reports. When using the EuroQol 5L questionnaire (scale 0-100) as a QoL tool 6 months post-LVAD implantation, a meta-analysis of four included studies demonstrated a mean difference increase of 28.9 points (95% confidence interval: 26.71-31.14).

CONCLUSIONS

Third-generation LVADs confer a significant improvement in QoL and their use can be supported not only for prognosis but also for symptom control. Although methodological limitations should be considered, the available QoL outcomes can be a useful tool in patient selection and the decision-making process.

Continuous-flow left ventricular assist device: Current knowledge, complications, and future directions

Long-term continuous-flow left ventricular assist devices have become a real alternative to heart transplantation in patients with advanced heart failure, achieving a promising 2-year event-free survival rate with new-generation devices. Currently, this technology has spread throughout the world, and any cardiologist or cardiac surgeon should be familiar with its fundamentals and its possible complications as well as the advances made in recent years. The aim of this review is to describe current knowledge, management of complications, and future directions of this novel heart-failure therapy.

Multi-constituent simulation of thrombus formation at LVAD inlet cannula connection: Importance of Virchow's triad

As pump thrombosis is reduced in current-generation ventricular assist devices (VAD), adverse events such as bleeding or stroke remain at unacceptable rates. Thrombosis around the VAD inlet cannula (IC) has been highlighted as a possible source of stroke events. Recent computational fluid dynamics (CFD) studies have attempted to characterize the thrombosis risk of different IC-ventricle configurations. However, purely CFD simulations relate thrombosis risk to ad hoc criteria based on flow characteristics, with little consideration of biochemical factors. This study investigates the genesis of IC thrombosis including two elements of the Virchow's triad: endothelial injury and hypercoagulability. To this end a multi-scale thrombosis simulation that includes platelet activity and coagulation reactions was performed. Our results show significant thrombin formation in stagnation regions (|u| < 0.005 m/s) close to the IC wall. In addition, high shear-mediated platelet activation was observed over the leading-edge tip of the cannula. The current study reveals the importance of biochemical factors to the genesis of thrombosis at the ventricular-cannula junction in a perioperative state. This study is a first step toward the long-term objective of including clinically relevant pharmacological kinetics such as heparin or aspirin in simulations of inflow cannula thrombosis.

Validation of a Miniaturized Test Loop for the Assessment of Human Blood Damage by Continuous-Flow Left-Ventricular Assist Devices

Despite improved hemocompatibility of left-ventricular assist devices (LVADs), assessment of blood damage remains mandatory in preclinical testing as standardized by ASTM-F1841. The most relevant test fluid is fresh, non-pooled human blood, but the limited volume of a standard donation requires significantly smaller loops than those commonly used with animal blood. In a recent study with porcine blood, we verified a miniaturized test loop with only 160 mL for the ASTM-conform paired testing of at least two LVADs and a static reference. Here, we validated this mini test loop for standardized assessment of blood damage with one 450-mL single donation of fresh human blood. Blood damage was assessed for HeartMate 3 and BPX-80 in 9 experiments with heparinized human blood for 6 hours. We analyzed plasma free hemoglobin, von Willebrand factor (vWF) concentration and collagen-binding functionality and calculated indices of hemolysis and vWF-ratios. Overall, we observed less blood damage compared to our previous study; however, the differences in mean indices of hemolysis and in mean normalized vWF-ratio between BPX-80 and HeartMate 3 were consistent for human blood. Thus, our mini test loop proved to be valid for preclinical standardized assessment of blood damage with only 450 mL of fresh human blood.

Retrospective 1-year outcome follow-up in 200 patients supported with HeartMate 3 and HeartWare left ventricular assist devices in a single centre

OBJECTIVES

Various trials have assessed the outcome and reliability of the HeartWare HVAD (HW) and HeartMate 3 (HM3) left ventricular assist devices. A direct comparison of clinical outcomes and of the complication profile of these 2 left ventricular assist devices is lacking. We present a retrospective analysis of patients supported with HM3 and HW as a left ventricular assist device.

METHODS

Preoperative data, complications and outcomes including a 1-year follow-up of patients supported with the HM3 and HW in a single centre were retrospectively analysed. Both pumps were implanted on- or off-pump, employing standard and minimally invasive techniques. For logistic reasons, the 2 device types were implanted in an alternating manner, thereby reducing the systematic bias for pump selection. We considered this to be an appropriate approach, as no differences in respect of survival or the complication profile of the two device types have been demonstrated. Anticoagulation was similar in patients with both pumps according to our anticoagulation protocol, with a target international normalized ratio of 2.5-3.0, a home monitoring system and blood pressure management with a mean arterial target pressure of 70-80 mmHg.

RESULTS

Between October 2015 and April 2017, 100 patients underwent implantation of the HW and 100 patients underwent implantation of the HM3. The median time on the device was 0.98 years (range 0-2.23 years). The median age was 58.5 (51-65) versus 57 (49-64) years (P = 0.456); the number of male patients was 87 versus 88 (P = 0.831). Of the HW patients, 73% were rated as having an INTERMACS level I or II, compared to 57% of the HM3 patients (P = 0.018). There were no further differences in preoperative data. A total of 14 patients had pre-, intra- or post-pump blood flow obstruction in the HW group versus 4 in the HM3 group [hazard ratio (HR) 2.5 (0.7-8.8), P = 0.103]. There were no differences regarding gastrointestinal bleeding [HR 1.25 (0.56-2.64), P = 0.624] or driveline infection (0.68 vs 0.8 events per patient-year, P = 0.0789). The incidence of ischaemic stroke was similar in both groups [HR 0.72 (0.25-2.09), P = 0.550]. Cerebral bleeding was more frequent in patients supported with HW [HR 6.79 (1.43-32.20), P = 0.016]. The incidence of cerebrovascular accidents, on the other hand, was similar in both groups [HR 1.85 (0.83-4.19), P = 0.13]. The incidence of haemocompatibility-related adverse events, however, was significantly higher in the HW group (113 points corresponding to 1.28 events per patient-year versus 69 points corresponding to 0.7 events per patient-year, P < 0.001). The 1-year survival was similar in both groups [62.2%, 95% confidence interval (CI) (0.53-0.73) vs 66.7%, 95% CI (0.58–0.767) [corrected].

CONCLUSIONS

Our data show that the complication profile differs between the 2 pumps, but that early survival is comparable.

Outcomes of Ambulatory Heart Failure Patients Managed With an Intra-aortic Balloon Pump Before Left Ventricular Assist Device Implantation

Patients are admitted to the hospital for hemodynamic optimization before left ventricular assist device (LVAD) implantation. The aim of this study was to evaluate the clinical outcomes of hemodynamic optimization using an intra-aortic balloon pump (IABP) in ambulatory heart failure patients before LVAD placement. This retrospective single-center study included 199 noninotrope-dependent patients who underwent durable LVAD implantation between January 1, 2007 and April 10, 2017. Invasive hemodynamic as well as the primary composite end-point of stage 2 or 3 acute kidney injury, right ventricular failure, and 30-day mortality were compared between patients with and without an IABP. Median age was 64 (interquartile range [IQR], 57-71) years and 165 (82.9%) were male; 72 (36.2%) received an IABP. Patients treated with an IABP had worse baseline exercise capacity and hemodynamic parameters. Patients with an IABP had greater relative reduction in pulmonary artery mean pressure (-16% vs. -2%; p ≤ 0.001). The primary composite end-point was not different between patients who had an IABP and those who did not (20.8% vs. 20.5%; p = 0.952), as were each of the individual end-points. Despite worse baseline hemodynamic parameters and exercise capacity, ambulatory heart failure patients who received an IABP before LVAD implantation had more favorable reductions in pulmonary artery pressures without an increase in the composite end-point. These results suggest that IABP use before LVAD implantation may mitigate the risk of postoperative complications in ambulatory patients.

Two-year outcome after implantation of a full magnetically levitated left ventricular assist device: results from the ELEVATE Registry

AIMS

The ELEVATE Registry was designed to study long-term outcomes with the Heartmate 3 (HM3), a fully magnetically levitated centrifugal ventricular assist device, in a real-world population following CE-mark approval.

METHODS AND RESULTS

A total of 540 patients, implanted in Europe and the Middle East were followed in ELEVATE. The registry included 463 patients receiving the HM3 as primary implant (Primary Implant Cohort), 19 patients underwent a pump upgrade from another device (Pump Exchange Cohort) and 58 patients who had experienced an outcome before having the possibility to sign the Informed Consent, for which only outcome data were collected (Anonymized Cohort). Data collection included demographics, survival, adverse events, EQ-5D Visual Analog Score quality of life (EQ-5D VAS QOL) questionnaire, and 6-min walk distance (6MWD). Mean age was 55.6 ± 11.7 years (89% male, 48% ischaemic cardiomyopathy). Seventy per cent of patients were in INTERMACS Profile 1-3 and 12.7% were on temporary mechanical circulatory support. Primary Implant Cohort survival was 83% after 2 years. In the Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation Primary Implant Cohort, strokes were observed in 10.2%, gastrointestinal bleedings in 9.7%, pump thrombosis in 1.5%, and outflow graft twists in 3.5%. Heartmate 3 implantation resulted in a significant and sustained improvement of functional capacity and QOL.

CONCLUSION

In a real-world population, cohort implanted with the HM3 left ventricular assist device we demonstrate good long-term survival, sustained improvement of functional capacity, and low rates of adverse events (including pump thrombosis).

CLINICALTRIALS.GOV IDENTIFIER

NCT02497950.

Antiphospholipid antibody syndrome and LVAD: What are the chances? A case report and literature review

Left-ventricular-assist-device (LVAD) implantation in patients with antiphospholipid-syndrome (APS) is considered a high-risk procedure and its indication still represents an open challenge. Herein, we report a 63-year-old man with APS and end-stage heart failure, for whom a HeartMate3-LVAD and a continuous rheologic profile monitoring with a multiparametric assessment resulted the optimal therapeutic strategy.

Heart transplant waiting list implications of increased ventricular assist device use as a bridge strategy: A national analysis

The use of ventricular assist devices (VADs) as a bridge to heart transplant (HT) is increasing, while HT volume remains stagnant. This may portend longer waiting times and an otherwise more competitive environment for all patients on the HT waiting list. A retrospective analysis of patients who were listed for HT in the United Network for Organ Sharing (UNOS) database from 2000 to 2015 was conducted. Mean waiting time, proportion of HT reception (%HT), proportion of death (%death), and proportion of waiting list removal (%removal) were calculated across three eras: Era 1 (2000-2007), Era 2 (2008-2011), and Era 3 (2012-2015). During the study period, 29 728 patients successfully underwent HT. 19 127 (64.3%) were directly transplanted (direct HT); 4491 (15.1%) received VADs prior to listing as a bridge to decision (BTD); and 4593 (15.5%) received VADs after listing as a bridge to transplant (BTT). Across the three eras, the average number of registrants per year grew. Among all groups, waiting time increased across the eras. %HT generally decreased in the BTD and BTT groups but remained constant in the direct HT group. %removal increased, while %death decreased in all group across the eras. Waiting time for HT increased from 2000 to 2015. Patients with VADs as a bridge strategy experienced decreasing %HT and increasing %removal but stable survival. Improvements in VAD safety and durability will ensure their success as part of a bridge strategy to HT under the new UNOS allocation policy.

Durable Continuous-Flow Mechanical Circulatory Support: State of the Art

Implantable mechanical circulatory support (MCS) systems for ventricular assist device (VAD) therapy have emerged as an important strategy due to a shortage of donor organs for heart transplantation. A growing number of patients are receiving permanent assist devices, while fewer are undergoing heart transplantation (Htx). Continuous-flow (CF) pumps, as devices that can be permanently implanted, show promise for the treatment of both young and old patients with heart failure (HF). Further improvement of these devices will decrease adverse events, enable pulse modulation of continuous blood flow, and improve automatic remote monitoring. Ease of use for patients could also be improved. We herein report on the current state of the art regarding implantable CF pumps for use as MCS systems in the treatment of advanced refractory HF.

Current era left ventricular assist devices

Left ventricular assist devices (LVADs) have changed the landscape of treatment options for patients with end stage heart failure. Due to the limited availability of donor hearts for transplantation, LVADs have become an important option for many of these patients. Much progress has been made in the device industry since then, and newer devices continue to improve patient outcomes. In this review, we will discuss some of the key transitions in LVADs over the years, the current LVADs used in practice today, implantation techniques, the impact of the new heart allocation system on LVAD use and future prospective LVADs.

A model for continued LVAD patient success: A 4-year readmission-free HeartMate 3 postoperative course

Unplanned readmissions frequently occur following the implantation of a durable left ventricular assist device (LVAD) due to complications such as gastrointestinal bleeding and driveline infection. There is a paucity of literature describing the incidence of unplanned readmission in patients with a HeartMate 3 (HM3) Left Ventricular Assist System. In this report, we present the successful outcome of a patient with an HM3 LVAD who has experienced no unplanned readmissions in the 4-year post-implant phase. To our knowledge, this is the longest readmission-free case after HM3 implantation. A successful patient outcome was enabled by the use of the modular HM3 device, the postoperative prescription of beta-blockers and omega-3, the presence of strong social support, and open communication between the patient's caregivers and the LVAD team. Reducing the instance of unplanned readmission confers clinical benefits to the patient, as well as reducing the cost burden on the patient and the healthcare system.

Carotid artery structure and hemodynamics and their association with adverse vascular events in left ventricular assist device patients

Left ventricular assist devices (LVADs) are associated with major vascular complications including stroke and gastrointestinal bleeding (GIB). These adverse vascular events may be the result of widespread vascular dysfunction resulting from pre-LVAD abnormalities or continuous flow during LVAD therapy. We hypothesized that pre-existing large artery atherosclerosis and/or abnormal blood flow as measured in carotid arteries using ultrasonography are associated with a post-implantation composite adverse outcome including stroke, GIB, or death. We retrospectively studied 141 adult HeartMate II patients who had carotid ultrasound duplex exams performed before and/or after LVAD surgery. Structural parameters examined included plaque burden and stenosis. Hemodynamic parameters included peak-systolic, end-diastolic, and mean velocity as well as pulsatility index. We examined the association of these measures with the composite outcome as well as individual subcomponents such as stroke. After adjusting for established risk factors, the composite adverse outcome was associated with pre-operative moderate-to-severe carotid plaque (OR 5.08, 95% CI 1.67-15.52) as well as pre-operative internal carotid artery stenosis (OR 9.02, 95% CI 1.06-76.56). In contrast, altered hemodynamics during LVAD support were not associated with the composite outcome. Our findings suggest that pre-existing atherosclerosis possibly in combination with LVAD hemodynamics may be an important contributor to adverse vascular events during mechanical support. This encourages greater awareness of carotid morphology pre-operatively and further study of the interaction between hemodynamics, pulsatility, and structural arterial disease during LVAD support.

Determinants of Functional Capacity and Quality of Life After Implantation of a Durable Left Ventricular Assist Device

Continuous-flow left ventricular assist devices (LVAD) are increasingly used as destination therapy in patients with end-stage heart failure and, with recent improvements in pump design, adverse event rates are decreasing. Implanted patients experience improved survival, quality of life (QoL) and functional capacity (FC). However, improvement in FC and QoL after implantation is not unequivocal, and this has implications for patient selection and preimplantation discussions with patients and relatives. This article identifies preimplantation predictors of lack of improvement in FC and QoL after continuous-flow LVAD implantation and discusses potential mechanisms, allowing for the identification of potential factors that can be modified. In particular, the pathophysiology behind insufficient improvement in peak oxygen uptake is discussed. Data are included from 40 studies, resulting in analysis of >700 exercise tests. Mean peak oxygen uptake was 13.4 ml/kg/min (equivalent to 48% of predicted value; 259 days after implantation, range 31–1,017 days) and mean 6-minute walk test distance was 370 m (182 days after implantation, range 43–543 days). Finally, the interplay between improvement in FC and QoL is discussed.

Ventricular Assist Devices and Their Usage as a Bridge to Recovery in Patients With Acute Cardiotoxicity and Cardiomyopathy

Cardiotoxicity can reduce the heart's function temporarily and is most commonly caused by radiation, immune reactions, and certain medications. Using a left ventricular assist device (LVAD) as a bridging therapy while waiting for cardiac recovery has been popular lately in patients who have a reduced ejection fraction after significant cardiac injury. Here we analyze the use of LVAD as a bridging therapy in three cases with chemotherapy-induced cardiotoxicity, acute myocarditis, and postpartum cardiac failure. Although LVADs are infamous for their device-related complications, the ejection fraction can increase up to 50% within days to months of usage without any complications in acute cardiotoxic patients that have no underlying significant risk factors or co-morbidities. Hence LVADs are excellent supportive devices while waiting for cardiac recovery, both in maintaining cardiac function and improving the associated organ failures.

Comprehensive review of hemolysis in ventricular assist devices

Ventricular assist devices (VADs) have played an important role in altering the natural history of end-stage heart failure. Low-grade hemolysis has been traditionally described in patients with VADs, indicating effective device functionality. However, clinically significant hemolysis could be crucial in terms of prognosis, calling for prompt therapeutic actions. The absence of solid and widely approved diagnostic criteria for clinically significant hemolysis, render the utilization of hemolysis laboratory markers challenging. Hemolysis incidence varies (5%-18%) depending on definition and among different VAD generations, being slightly higher in continuous-flow devices than in pulsatile devices. Increased shear stress of red blood cells and underlying device thrombosis appear to be the main pathogenetic pathways. No certain algorithm is available for the management of hemolysis in patients with VADs, while close clinical and laboratory monitoring remains the cornerstone of management. Imaging examinations such as echocardiography ramp test or computed tomography scan could play a role in revealing the underlying cause. Treatment should be strictly personalized, including either pharmacological (antithrombotic treatment) or surgical interventions.

Predictors of Physical Capacity 6 Months After Implantation of a Full Magnetically Levitated Left Ventricular Assist Device: An Analysis From the ELEVATE Registry

BACKGROUND

In patients with a continuous-flow left ventricular assist device, preimplant predictors of poor physical performance are not well-described. We aimed to identify predictors of inability to walk more than 300 m on 6-minute walk test (6MWT) 6 months after HeartMate 3 implantation.

METHODS AND RESULTS

Using data from the European Registry of Patients Implanted With a Full Magnetically Levitated LVAD, patients with available 6MWT at 6 months after implantation were included (N = 194) and grouped according to 6MWT distance (6MWD) of >300 m (n = 150) or 6MWD of <300 m (n = 44). Patients walking <300 m were older (60 ± 10 vs 52 ± 12 years; P < .001), more often New York Heart Association functional class IV (63% vs 42%; P = .03), and more often had type 2 diabetes (43% vs 17%; P < .001) at implantation. Atrial fibrillation was seen in 57% in those with a 6MWT of <300 m vs 31% in those walking longer (P < .002). Further, hemoglobin and estimated glomerular filtration rate was lower in those walking <300 m (both P < .01). In multivariable regression analysis, independent predictors of a 6MWD of <300 m were: atrial fibrillation (odds ratio [OR], 3.22; 95% confidence interval [CI], 1.12-8.67), older age (OR for 10-year increment, 2.81; 95% CI, 1.55-5.07), New York Heart Association functional class IV (OR, 3.37; 95% CI, 1.27-8.98), and Interagency Registry for Mechanically Assisted Circulatory Support profile 1 or 2 (OR, 6.53; 95% CI, 1.92-22.19).

CONCLUSIONS

Six months after HeartMate 3 implantation, 77% of patients walked >300 meters in 6 minutes. Apart from age and measures of heart failure severity, atrial fibrillation at implantation is an independent predictor of low 6MWD at 6 months after implantation.

Acute Pump Thrombosis in the Early Postoperative Period After HeartMate 3 Implantation

There are no reports of acute pump thrombosis in the latest, continuous flow left ventricular assist devices type HeartMate 3, other than thrombus ingestion. We present a case of early thrombosis of the pump and outflow graft, necessitating acute pump and outflow graft replacement. A combination of low-flow episodes and subtherapeutic levels of anticoagulation was the most likely cause.

Outcome of patients receiving a continuous flow left ventricular assist device - a retrospective single center study

Objectives. We present the outcome of the first 80 patients receiving a continuous flow left ventricular assist device at Helsinki University Hospital between December 2011 and November 2018. Design. This was a single-center retrospective study. We describe our patient management in detail. The primary end-points were death, heart transplantation, or pump explant. Data was reported in accordance with the Interagency Registry for Mechanical Circulatory Support protocol. All patients receiving an assist device during the study period were included in the data analysis. Results. Mean patient age was 53 ± 12 years at implantation and 85% were male. Most patients suffered from dilated (48%), or ischemic (40%) cardiomyopathy. One-third of patients were bridged with venoarterial extracorporeal membrane oxygenation to assist device implantation. Implant strategy was bridge to transplant or bridge to decision in most patients (88%). Mean follow-up time on pump was 529 ± 467 days. Survival was 98, 92, 85, 79 and 71% at 1, 3, 12, 24 and 36 months, respectively. Most common causes of death were multi-organ failure, right heart failure, or stroke. Only three patients (4%) had suspected pump thrombosis, two of which resolved with medical treatment and one resulting in death. Pump exchange or explant were not performed in a single patient. Neurological events occurred in 18%, non-disabling stroke in 8%, and fatal stroke in 4% of the patients. The incidence of device-related infection was 10%. Conclusions. Survival rates were good, although one third of patients were bridged with temporary circulatory support. We report a high level of freedom from pump thrombosis, fatal stroke, and driveline infection.

Initial Canadian Experience With Bilateral Minithoracotomy Approach for HeartMate 3 Left Ventricular Assist Device Implantation

Left ventricular assist devices provide hemodynamic support to improve quality of life and long-term survival in patients with end-stage heart failure. The HeartMate 3 (Abbott, Abbott Park, IL) left ventricular assist device uses magnetically levitated impeller technology, improving durability and reducing pump thrombosis. Sternum-sparing implantation may reduce perioperative bleeding and infection, improve mobility, decrease hospitalization duration, and reduce right ventricular dysfunction. We describe the first Canadian HeartMate 3 implantation via bilateral minithoracotomy. Our case supports the compatibility of the HeartMate 3 device with sternum-sparing approaches and highlights the feasibility of intrapericardial tunnelling of the outflow graft.

Interpreting Neurologic Outcomes in a Changing Trial Design Landscape: An Analysis of HeartWare Left Ventricular Assist Device Using a Hybrid Intention to Treat Population

Randomized controlled trials can provide optimal clinical evidence to assess the benefits of new devices, and it is these data that often shape device usage in real-world practice. However, individual clinical trial results sometimes appear discordant for the same device, and alternative devices are sometimes not employed in similar patient populations. To make sound evidence-based decisions, clinicians routinely rely on cross-trial comparisons from different trials of similar but not identical patient populations to assess competing technology when head-to-head randomized comparisons are unavailable.

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.

Computational characterization of flow and blood damage potential of the new maglev CH-VAD pump versus the HVAD and HeartMate II pumps

Left ventricular assist devices are routinely used to treat patients with advanced heart failure as a bridge to transplant or a destination therapy. However, non-physiological shear stress generated by left ventricular assist devices damages blood cells. The continued development of novel left ventricular assist devices is essential to improve the left ventricular assist device therapy for heart failure patients. The CH-VAD is a new maglev centrifugal left ventricular assist device. In this study, the CH-VAD pump was numerically analyzed and compared with the HVAD and HeartMate II pumps under two clinically relevant conditions (flow: 4.5 L/min, pressure head: normal ~80 and hypertension ~120 mmHg). The velocity and shear stress fields, washout, and hemolysis index of the three pumps were assessed with computational fluid dynamics analysis. Under the same condition, the CH-VAD hemolysis index was two times lower than the HVAD and HeartMate II pumps; the CH-VAD had the least percentage volume with shear stress larger than 100 Pa (i.e. normal condition: 0.4% vs HVAD 1.0%, and HeartMate II 2.9%). Under the normal condition, more than 98% was washed out of the three pumps within 0.4 s. The washout times were slightly shorter under the hypertension condition for the three pumps. No regions inside the CH-VAD or HVAD had extremely long residential time, while areas near the straightener of the HeartMate II pump had long residential time (>4 s) indicating elevated risks of thrombosis. The computational fluid dynamics results suggested that the CH-VAD pump has a better hemolytic biocompatibility than the HVAD and HeartMate II pumps under the normal and hypertension conditions.

Implantation of a HeartMate 3 in a 13-Year-Old Child with Dilated Cardiomyopathy

Left ventricular assist device is a well-established therapy in heart failure adults, but less in children. A 13-year-old-boy with severe left ventricular dysfunction did not improve under medical treatment. A HeartMate 3 (HM3) was implanted as a bridge to transplantation. Despite the size limitation, the HM3 shows promising results and our case supports its feasibility in children.

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.

Ventricular Flow Field Visualization During Mechanical Circulatory Support in the Assisted Isolated Beating Heart

Investigations of ventricular flow patterns during mechanical circulatory support are limited to in vitro flow models or in silico simulations, which cannot fully replicate the complex anatomy and contraction of the heart. Therefore, the feasibility of using echocardiographic particle image velocimetry (Echo-PIV) was evaluated in an isolated working heart setup. Porcine hearts were connected to an isolated, working heart setup and a left ventricular assist device (LVAD) was implanted. During different levels of LVAD support (unsupported, partial support, full support), microbubbles were injected and echocardiographic images were acquired. Iterative PIV algorithms were applied to calculate flow fields. The isolated heart setup allowed different hemodynamic situations. In the unsupported heart, diastolic intra-ventricular blood flow was redirected at the heart’s apex towards the left ventricular outflow tract (LVOT). With increasing pump speed, large vortex formation was suppressed, and blood flow from the mitral valve directly entered the pump cannula. The maximum velocities in the LVOT were significantly reduced with increasing support. For the first time, cardiac blood flow patterns during LVAD support were visualized and quantified in an ex vivo model using Echo-PIV. The results reveal potential regions of stagnation in the LVOT and, in future the methods might be also used in clinical routine to evaluate intraventricular flow fields during LVAD support.

Long-term discontinuation of warfarin in a patient with HeartMate 3 left ventricular assist device without complication

A 38-year-old woman with peripartum cardiomyopathy underwent placement of a HeartMate 3 (HM3) left ventricular assist device (LVAD). Postoperatively, she refused warfarin therapy and was maintained on aspirin monotherapy for 19 months. She did not experience thrombotic or thromboembolic complications associated with lack of oral vitamin K antagonist anticoagulation. Our patient represents the longest reported duration of a patient with HM3 LVAD maintained without warfarin without evidence of thrombotic or thromboembolic events.

Trends in HeartMate 3: What we know so far

BACKGROUND

The HeartMate 3 left ventricular assist device (LVAD) is a novel, intrapericardial, centrifugal-flow pump with a fully magnetically-levitated rotor designed to provide hemodynamic support in patients with end-stage heart failure. Unique aspects of this LVAD have allowed for improved hemocompatibility and the development of minimally-invasive implantation techniques.

METHODS

The PubMed, EMBASE, and Google Scholar databases were searched for publications relating to the HeartMate 3 device, with a focus on hemocompatibility related outcomes, anticoagulation management, and surgical techniques.

RESULTS

Nine articles analyzing hemocompatibility related outcomes from two clinical trials, two clinical studies, and one registry series were identified.

CONCLUSION

HeartMate 3 has reduced the rate of disabling stroke and pump thrombosis. However, despite increased hemocompatibility due to specialized design features, the residual risk of both surgical, and gastrointestinal bleeding remains a major adverse outcome. Different anticoagulation management and surgical techniques have been evaluated to address the remaining complications.

A Rising Hope of an Artificial Heart: Left Ventricular Assisted Device - Outcome, Convenience, and Quality of Life

With the introduction of mechanical circulatory support, mainly continuous-flow left ventricular assisted devices (CF-LVAD), prolonging survival in end-stage heart failure patients can be seen in a new light. We also anticipate its use as a definitive therapy to overcome the limited donor organ resources for cardiac transplant. However, LVADs also have undesirable device-related complications and questionable improvement in the quality of life. In this review, we searched published articles using PubMed and Google Scholar to identify the complications and outcome of post-LVAD patients from 2014 to 2019. The studies we used included all study design types and a wide range of demographic variables focusing on age, sex, choice of LVAD as a bridge to cardiac transplant, or definitive therapy. For patients with New York Heart Association (NYHA) Class III B or IV or heart failure with reduced ejection fraction (HFrEF) with maximal medication therapy, there is a significant increase in mean ejection fraction from 4% to 6%. For patients with drug-induced cardiac toxicity or other causes of cardiac toxicity, with no significant risk factors, the ejection fraction increased to nearly 50% within 10-25 days of LVAD usage. There is also a substantial improvement in the quality of life in this literature review comparing to the pre-LVAD stage, as long as complications are taken into account. Data is limited for making an accurate judgment on the quality of life and functional capacity of LVADs. We found that the use of LVADs is not fully cost-effective, but still less financially burdening than a cardiac transplant. Although data from worldwide is limited and restricted to studies having a range of one to two years of follow-up, we conclude that LVADs are promising in improving cardiac function and the best bridging therapy available for patients waiting on a transplant.

A Step-by-Step Problem-Solving Strategy in a Patient With Heart Failure and Cerebral Aneurysm

Left ventricular assist device implantation is an established treatment for patients with end-stage heart failure. The HeartMate 3 (Abbott Laboratories, Abbott Park, IL) is a continuous-flow centrifugal pump, recently introduced in the clinic, that has shown greater hemocompatibility compared with similar devices of previous generations. Nevertheless, anticoagulation is still required after HeartMate 3 implant to avoid pump dysfunction. Hereafter, we describe the case of a patient candidate to left ventricular assist device implantation for end-stage heart failure presenting a concomitant cerebrovascular lesion, accidentally found during preoperative assessment, that would have contraindicated the procedure (for the prohibitive risk of cerebral hemorrhage), unless a step by step problem-solving approach was adopted.

Novel Model to Predict Gastrointestinal Bleeding During Left Ventricular Assist Device Support

BACKGROUND

Gastrointestinal bleeding (GIB) is a leading cause of morbidity during continuous-flow left ventricular assist device (CF-LVAD) support. GIB risk assessment could have important implications for candidate selection, informed consent, and postimplant therapeutic strategies. The aim of the study is to derive and validate a predictive model of GIB in CF-LVAD patients.

METHODS AND RESULTS

CF-LVAD recipients at the Utah Transplantation Affiliated Hospitals program between 2004 and 2017 were included. GIB associated with a decrease in hemoglobin ≥2 g/dL was the primary end point. A weighted score comprising preimplant variables independently associated with GIB was derived and internally validated. A total of 351 patients (median age, 59 years; 82% male) were included. After a median of 196 days, GIB occurred in 120 (34%) patients. Independent predictors of GIB included age >54 years, history of previous bleeding, coronary artery disease, chronic kidney disease, severe right ventricular dysfunction, mean pulmonary artery pressure <18 mm Hg, and fasting glucose >107 mg/dL. A weighted score termed Utah bleeding risk score, effectively stratified patients based on their probability of GIB: low (0-1 points) 4.8%, intermediate (2-4) 39.8%, and high risk (5-9) 83.8%. Discrimination was good in the development sample (c-index: 0.83) and after internal bootstrap validation (c-index: 0.74).

CONCLUSIONS

The novel Utah bleeding risk score is a simple tool that can provide personalized GIB risk estimates in CF-LVAD patients. This scoring system may assist clinicians and investigators in designing tailored risk-based strategies aimed at reducing the burden posed by GIB in the individual CF-LVAD patient and healthcare systems.

A real-life experience with HeartMate III

BACKGROUND

The HeartMate III (HM3) left ventricular assist device (LVAD) is the most recent LVAD to receive CE Mark and the Food and Drug Administration approval. It is a fully magnetically levitated pump with no reported haemolysis, pump thrombosis or pump failure in the first in-man study (a previous stody). It has now received market approval in the European Union, United States of America, and Australia. We reviewed our real-life experience with the device, to assess outcomes over the medium term.

METHODS

We conducted a retrospective review of prospectively collected data for 33 consecutive patients implanted with a HM3 LVAD between November 2014 and October 2018 at The Alfred Hospital, Melbourne, Australia.

RESULTS

Of the 33 patients, 31 remained alive at the census date, with only two early deaths and 11 patients transplanted. There were no pump thromboses, but there were three cases of clot ingestion (two on the right and one on the left). Seven patients required permanent biventricular assist device support. The duration of HM3 support at the time of census was a median of 196 (interquartile range, 118-386) days.

CONCLUSION

This series demonstrates excellent results of the HM3 LVAD in an uncensored, real-life, consecutive group of patients in a single institution.

2019 EACTS Expert Consensus on long-term mechanical circulatory support

Long-term mechanical circulatory support (LT-MCS) is an important treatment modality for patients with severe heart failure. Different devices are available, and many-sometimes contradictory-observations regarding patient selection, surgical techniques, perioperative management and follow-up have been published. With the growing expertise in this field, the European Association for Cardio-Thoracic Surgery (EACTS) recognized a need for a structured multidisciplinary consensus about the approach to patients with LT-MCS. However, the evidence published so far is insufficient to allow for generation of meaningful guidelines complying with EACTS requirements. Instead, the EACTS presents an expert opinion in the LT-MCS field. This expert opinion addresses patient evaluation and preoperative optimization as well as management of cardiac and non-cardiac comorbidities. Further, extensive operative implantation techniques are summarized and evaluated by leading experts, depending on both patient characteristics and device selection. The faculty recognized that postoperative management is multidisciplinary and includes aspects of intensive care unit stay, rehabilitation, ambulatory care, myocardial recovery and end-of-life care and mirrored this fact in this paper. Additionally, the opinions of experts on diagnosis and management of adverse events including bleeding, cerebrovascular accidents and device malfunction are presented. In this expert consensus, the evidence for the complete management from patient selection to end-of-life care is carefully reviewed with the aim of guiding clinicians in optimizing management of patients considered for or supported by an LT-MCS device.

Sound analysis of the magnetically levitated left ventricular assist device HeartMate 3™

Introduction:

The HeartMate 3™ has shown lower rates of adverse events compared to previous devices due to the design and absence of mechanical bearings. For previous devices, sound analysis emerged as a way to assess pump function. The aims of this study were to determine if sound analysis can be applied to the HeartMate 3 in vivo and in vitro and to evaluate an electronic stethoscope.

Method:

Sound recordings were performed with microphones and clinical accessible electronic stethoscope. The recordings were studied in both the time and the frequency domains. Recordings from four patients were performed to determine if in vivo and in vitro recordings are comparable.

Results:

The results show that it is possible to detect sound from HeartMate 3 and the sound spectrum is clear. Pump frequency and frequency of the pulsatile mode are easily determined. Frequency spectra from in vitro and in vivo recordings have the same pattern, and the major proportion (96.7%) of signal power is located at the pump speed frequency ±40 Hz. The recordings from the patients show low inter-individual differences except from location of peaks originating from pump speed and harmonics. Electronic stethoscopes could be used for sound recordings, but the dedicated equipment showed a clearer sound spectrum.

Discussion:

The results show that acoustic analysis can also be performed with the HeartMate 3 and that in vivo and in vitro sound spectrum is similar. The frequency spectra are different from previous devices, and methods for assessing pump function or thrombosis need further evaluation.

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.

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.

Artificial shear stress effects on leukocytes at a biomaterial interface

Medical devices, such as ventricular assist devices (VADs), introduce both foreign materials and artificial shear stress to the circulatory system. The effects these have on leukocytes and the immune response are not well understood. Understanding how these two elements combine to affect leukocytes may reveal why some patients are susceptible to recurrent device-related infections and provide insight into the development of pump thrombosis. Biomaterials-DLC: diamond-like carbon-coated stainless steel; Sap: single-crystal sapphire; and Ti: titanium alloy (Ti₆ Al₄ V) were attached to the parallel plates of a rheometer. Whole human blood was left between the two discs for 5 minutes at +37°C with or without the application of shear stress (0 s^-1 or 1000 s^-1 ). Blood was removed and used for complete blood cell counts, flow cytometry (leukocyte activation, cell death, microparticle generation, phagocytic ability, and reactive oxygen species [ROS] production), and the production of pro-inflammatory cytokines. L-selectin expression on monocytes was decreased when blood was exposed to the biomaterials both with and without shear. Applying shear stress to blood on a Sap and Ti surface led to activation of neutrophils shown as decreased L-selectin expression. Sap and Ti blunted the LPS-stimulated macrophage migration inhibitory factor (MIF) production, most notably when sheared on Ti. The biomaterials used here have been shown to activate leukocytes in a static environment. The introduction of shear appears to exacerbate this activation. Interestingly, a widely accepted biocompatible material (Ti) utilized in many different types of devices has the capacity for immune cell activation and inhibition of MIF secretion when combined with shear stress. These findings contribute to our understanding of the contribution of biomaterials and shear stress to recurrent infections and vulnerability to sepsis in some VAD patients as well as pump thrombosis.