Left ventricular assist devices and their complications: A review for emergency clinicians

Percutaneous Intervention of LVAD Outflow Graft Obstruction and Thrombosis

Left ventricular assist devices serve as a salvage therapy for patients with advanced heart failure. Complications such as thrombosis and obstruction can lead to acute device malfunction, posing significant clinical risks. A multidisciplinary approach is crucial for management. Few cases in the literature have demonstrated the safety and efficacy of percutaneous intervention, which holds significant value due to its less invasive nature and minimal risk of morbidity, especially in high-risk surgical patients.

Hemolysis Index Correlations with Plasma-Free Hemoglobin and Plasma Lactate Dehydrogenase in Critically Ill Patients under Extracorporeal Membrane Oxygenation or Mechanical Circulatory Support-A Single-Center Study

Monitoring for thrombosis and hemolysis is crucial for patients under extracorporeal or mechanical circulatory support, but it can be costly. We investigated correlations between hemolysis index (HI) and plasma-free hemoglobin (PFH) levels on one hand, and between the HI and plasma lactate dehydrogenase (LDH) levels on the other, in critically ill patients with and without extracorporeal or mechanical circulatory support. Additionally, we calculated the cost reductions if monitoring through HI were to replace monitoring through PFH or plasma LDH. In a single-center study, HI was compared with PFH and plasma LDH levels in blood samples taken for routine purposes in critically ill patients with and without extracorporeal or mechanical circulatory support. A cost analysis, restricted to direct costs associated with each measurement, was made for an average 10-bed ICU. This study included 147 patients: 56 patients with extracorporeal or mechanical circulatory support (450 measurements) and 91 patients without extracorporeal or mechanical circulatory support (562 measurements). The HI correlated well with PFH levels (r = 0.96; p < 0.01) and poorly with plasma LDH levels (r = 0.07; p < 0.01) in patients with extracorporeal or mechanical circulatory support. Similarly, HI correlated well with PFH levels (r = 0.97; p < 0.01) and poorly with plasma LDH levels (r = -0.04; p = 0.39) in patients without extracorporeal or mechanical circulatory support. ROC analyses demonstrated a strong performance of HI, with the curve indicating excellent discrimination in the whole cohort (area under the ROC of 0.969) as well as in patients under ECMO or mechanical circulatory support (area under the ROC of 0.988). Although the negative predictive value of HI for predicting PFH levels > 10 mg/dL was high, its positive predictive value was found to be poor at various cutoffs. A simple cost analysis showed substantial cost reduction if HI were to replace PFH or plasma LDH for hemolysis monitoring. In conclusion, in this cohort of critically ill patients with and without extracorporeal or mechanical circulatory support, HI correlated well with PFH levels, but poorly with plasma LDH levels. Given the high correlation and substantial cost reductions, a strategy utilizing HI may be preferable for monitoring for hemolysis compared to monitoring strategies based on PFH or plasma LDH. The PPV of HI, however, is unacceptably low to be used as a diagnostic test.

Postoperative care of 14 patients with left ventricular assist devices: a case series

A left ventricular assist device is a mechanical device that is surgically implanted in the heart to partially or completely replace the function of the heart. Left ventricular assist devices are of vital importance in the treatment of patients with heart failure. There are different recommendations for the postoperative care of patients undergoing left ventricular assist device implantation in different countries, and no uniform standard has been developed. The first implantation of a left ventricular assist device in Eastern China was performed in February 2021; since that date, 14 patients underwent implantation until February 2023. This report describes the postoperative care of these 14 patients with end-stage heart failure who underwent left ventricular assist device placement, all of whom were discharged with a good prognosis.

Sex-based differences in ischemic cardiovascular and bleeding outcomes following implantation of drug-eluting stent in patients at high bleeding risk

BACKGROUND

Patients with high bleeding risk (HBR) may exhibit uncertain adherence to dual antiplatelet therapy (DAPT) following drug-eluting stent (DES) implantation. The current population-based cohort study aimed to investigate the sex-based differences in adverse outcomes among the HBR population by analyzing the National Health Insurance Research Database in Taiwan.

METHODS

Patients who had HBR features defined by the Academic Research Consortium (ARC) and received DES implantation between January 1, 2007, and December 31, 2017, were enrolled. Propensity score matching was adopted to select 3,981 pairs with similar clinical cardiovascular risks but different sexes. A competing risk model was performed to evaluate the risk of adverse ischemic events (cardiac death, nonfatal myocardial infarction, and ischemic stroke) and any bleeding events in both sexes. Noncardiac death was considered a competing risk.

RESULTS

Within a 5-year follow-up, the incidence rates (per 1,000 person-year (95% confidence interval (CI)) of composite ischemic events and any bleeding events in males were respectively 44.09 (40.25-48.30) and 42.55 (38.79-46.68), while those in females were respectively 40.18 (36.51-44.23) and 42.35 (38.57-46.51). After adjustment for clinical variables, male patients had a marginally increased risk in the composite ischemic events (adjusted subdistribution hazard ratio (SHR) = 1.15 (1.00-1.31), p = 0.045) and a similar risk of any bleeding events (adjusted SHR = 1.00 (0.88-1.15), p = 0.946) compared with female patients.

CONCLUSIONS

Of the HBR population, males had an increased risk of ischemic outcomes but a similar risk of bleeding compared with females following DES implantation.

PERSUADE Survey-PERioperative AnestheSia and Intensive Care Management of Left VentricUlar Assist DevicE Implantation in Europe and the United States

OBJECTIVE

To comprehensively assess relevant institutional variations in anesthesia and intensive care management during left ventricular assist device (LVAD) implantation.

DESIGN

The authors used a prospective data analysis.

SETTING

This was an online survey.

PARTICIPANTS

Participants were from LVAD centers in Europe and the US.

INTERVENTIONS

After investigating initial interest, 91 of 202 European and 93 of 195 US centers received a link to the survey targeting institutional organization and experience, perioperative hemodynamic monitoring, medical management, and postoperative intensive care aspects.

MEASUREMENTS AND MAIN RESULTS

The survey was completed by 73 (36.1%) European and 60 (30.8%) US centers. Although most LVAD implantations were performed in university hospitals (>5 years of experience), significant differences were observed in the composition of the preoperative multidisciplinary team and provision of intraoperative care. No significant differences in monitoring or induction agents were observed. Propofol was used more often for maintenance in Europe (p < 0.001). The choice for inotropes changed significantly from preoperatively (more levosimendan in Europe) to intraoperatively (more use of epinephrine in both Europe and the US). The use of quantitative methods for defining right ventricular (RV) function was reported more often from European centers than from US centers (p < 0.05). Temporary mechanical circulatory support for the treatment of RV failure was more often used in Europe. Nitric oxide appeared to play a major role only intraoperatively. There were no significant differences in early postoperative complications reported from European versus US centers.

CONCLUSIONS

Although the perioperative practice of care for patients undergoing LVAD implantation differs in several aspects between Europe and the US, there were no perceived differences in early postoperative complications.

Driveline dressings used in heartmate patients and local complications: A retrospective cohort

BACKGROUND

Patients with long-term ventricular assist devices (VAD) are predisposed to infection, bleeding, and pressure injuries at the insertion of the driveline. There is no consensus on a driveline dressing protocol. Chlorhexidine is often used to clean the driveline exit site and has been associated with lower rates of infection. For driveline coverage, bacteriostatic agents and transparent film have shown good results, but are costly. The same issue was associated with anchorage devices.

OBJECTIVES

The purpose of this study was to evaluate the types of dressings used in the driveline of patients using HeartMate (HM) and to describe the incidence density of local complications (infection, bleeding, and pressure injury) within 30 days postoperatively.

METHODS

A retrospective cohort study was conducted and included 22 patients admitted to the Intensive Care Unit after implantation of HM II and III in a Brazilian private hospital.

RESULTS

Several types of dressings were used in the drivelines. There were 22 different types of dressings. Dressing type 6 (Chlorhexidine, Excilon, Gauze and IV3000) were the most used (45.4%). Subjects using the Flexi-Trak anchoring device had a higher rate of local bleeding (50.0%) and those who used the Hollister device had more infection (61.1%) and pressure injury associated with a medical device (11.1%), compared to others. Infection was the primary complication (45.4%), followed by local bleeding (27.7%).

CONCLUSION

Despite the high variability of products used in the driveline of patients using HeartMate, the dressing made with chlorhexidine, silver-impregnated absorbent foam and transparent film, and the use of anchoring devices was the most frequently used. Infection was the most common complication.

Transcatheter aortic valve replacement for aortic insufficiency in a patient with aortic root Thrombus and left ventricular assist device: A risk worth taking?

A 61-year-old man with end-stage ischemic cardiomyopathy post HeartMate 3 (Abbott laboratories, Chicago, Illinois, USA) left ventricular assist device (LVAD) implant was hospitalized after he had recurrent ventricular tachycardia requiring implantable cardioverter-defibrillator shocks. His transthoracic echocardiogram and computed tomography angiography of the chest showed presence of trace aortic insufficiency (AI) and aortic root thrombus (ART) of non-coronary cusp without obstruction of right or left coronary artery ostium despite therapeutic international normalized ratio. He presented again 3 months later with worsening heart failure signs and symptoms. Transesophageal echocardiogram showed progression to severe AI and persistent ART. Despite hemodynamically guided LVAD speed optimization, inotropic support, and diuresis, the patient continued to deteriorate with worsening renal function. The patient was not a transplant candidate due to frailty. After multi-disciplinary discussion he underwent successful 29-Sapien S3 (Edwards Lifesciences, Irvine, CA, USA) transcatheter aortic valve replacement utilizing distal protection filters in bilateral internal carotid arteries for stroke prevention. This case provides novel insight to physicians treating LVAD patients regarding management of severe AI in the setting of ART.

Learning objective

We report a rare approach employed for management of aortic insufficiency (AI) in a patient who also had an aortic root thrombus and left ventricular assist device (LVAD) that traditionally requires cardiac transplantation. Our patient had a favorable outcome with a minimally invasive transcatheter aortic valve replacement. With this case, we hope to generate awareness amongst physicians treating patients about management alternatives and approach of a commonly encountered, life-threatening complication of AI in patients with LVAD.

Application of 1,000 fps High-Speed Angiography to In-Vitro Hemodynamic Evaluation of Left Ventricular Assist Device Outflow Graft Configurations

Left ventricular assist device (LVAD)-induced hemodynamics are characterized by fast-moving flow with large variations in velocity, making quantitative assessments difficult with existing imaging methods. This study demonstrates the ability of 1,000 fps high-speed angiography (HSA) to quantify the effect of the surgical implantation angle of a LVAD outflow graft on the hemodynamics within the ascending aorta in vitro . High-speed angiography was performed on patient-derived, three-dimensional-printed optically opaque aortic models using a nonsoluble contrast media, ethiodol, as a flow tracer. Outflow graft configuration angles of 45° and 90° with respect to the central aortic axis were considered. Projected velocity distributions were calculated from the high-speed experimental sequences using two methods: a physics-based optical flow algorithm and tracking of radio-opaque particles. Particle trajectories were also used to evaluate accumulated shear stress. Results were then compared with computational fluid dynamics (CFD) simulations to confirm the results of the high-speed imaging method. Flow patterns derived from HSA coincided with the impingement regions and recirculation zones formed in the aortic root as seen in the CFD for both graft configurations. Compared with the 45° graft, the 90° configuration resulted in 81% higher two-dimensional-projected velocities (over 100 cm/s) along the contralateral wall of the aorta. Both graft configurations suggest elevated accumulated shear stresses along individual trajectories. Compared with CFD simulations, HSA successfully characterized the fast-moving flow and hemodynamics in each LVAD graft configuration in vitro , demonstrating the potential utility of this technology as a quantitative imaging modality.

Prognostic value of mitral regurgitation in patients undergoing left ventricular assist device deployment: A systematic review and meta-analysis

BACKGROUND

Left ventricular assist devices (LVADs) represent an important therapeutic option for patients progressing to end-stage heart failure. LVAD has previously been shown to have a promising role in improving mitral regurgitation (MR). Nevertheless, the prognostic value of preoperative uncorrected MR in this population remains unclear.

METHODS

A systematic database search with meta-analysis was conducted of comparative original articles of patients with preoperative mild MR (Grade 0-I) versus moderate-severe MR (Grade II-III) undergoing LVAD implantation, in EMBASE, MEDLINE, Cochrane database, and Google Scholar, from inception to June 2022. Primary outcomes were overall and operative mortality. Secondary outcomes were neurological dysfunction, gastrointestinal bleeding, right heart failure, LVAD thrombosis, and driveline infection.

RESULTS

Our search yielded 2228 relevant studies. A total of 19 studies met the inclusion criteria with a total of 11 873 patients. LVAD caused a statistically significant decrease of 35.9% in the number of patients with moderate-severe MR (grade II-III) postoperatively. No significant difference was observed in terms of overall mortality, operative mortality, GI bleeding, LVAD thrombosis, and driveline infection rates between mild and moderate-severe MR. An increased rate of right heart failure was seen among patients with moderate-severe MR, while lower rates of neurological events were also observed.

CONCLUSION

LVAD improves the haemodynamics of the left ventricle, to promote resolution of MR. Nevertheless, the severity of preoperative mitral regurgitation in patients undergoing LVAD deployment does not seem to affect mortality.

Artificial Muscles and Soft Robotic Devices for Treatment of End-Stage Heart Failure

Medical soft robotics constitutes a rapidly developing field in the treatment of cardiovascular diseases, with a promising future for millions of patients suffering from heart failure worldwide. Herein, the present state and future direction of artificial muscle-based soft robotic biomedical devices in supporting the inotropic function of the heart are reviewed, focusing on the emerging electrothermally artificial heart muscles (AHMs). Artificial muscle powered soft robotic devices can mimic the action of complex biological systems such as heart compression and twisting. These artificial muscles possess the ability to undergo complex deformations, aiding cardiac function while maintaining a limited weight and use of space. Two very promising candidates for artificial muscles are electrothermally actuated AHMs and biohybrid actuators using living cells or tissue embedded with artificial structures. Electrothermally actuated AHMs have demonstrated superior force generation while creating the prospect for fully soft robotic actuated ventricular assist devices. This review will critically analyze the limitations of currently available devices and discuss opportunities and directions for future research. Last, the properties of the cardiac muscle are reviewed and compared with those of different materials suitable for mechanical cardiac compression.

Titanium is a potent inducer of contact activation: implications for intravascular devices

BACKGROUND

Titanium (Ti) and its alloys are widely used in manufacturing medical devices because of their strength and resistance to corrosion. Although Ti compounds are considered compatible with blood, they appear to support plasma contact activation and may be thrombogenic.

OBJECTIVES

The objective of this study was to compare Ti and titanium nitride (TiN) with known activators of contact activation (kaolin and silica) in plasma-clotting assays and to assess binding and activation of factor XII, (FXII), factor XI (FXI), prekallikrein, and high-molecular-weight kininogen (HK) with Ti/TiN.

METHODS

Ti-based nanospheres and foils were compared with kaolin, silica, and aluminum in plasma-clotting assays. Binding and activation of FXII, prekallikrein, HK, and FXI to surfaces was assessed with western blots and chromogenic assays.

RESULTS

Using equivalent surface amounts, Ti and TiN were comparable with kaolin and superior to silica, for inducing coagulation and FXII autoactivation. Similar to many inducers of contact activation, Ti and TiN are negatively charged; however, their effects on FXII are not neutralized by the polycation polybrene. Antibodies to FXII, prekallikrein, or FXI or coating Ti with poly-L-arginine blocked Ti-induced coagulation. An antibody to FXII reduced FXII and PK binding to Ti, kallikrein generation, and HK cleavage.

CONCLUSION

Titanium compounds induce contact activation with a potency comparable with that of kaolin. Binding of FXII with Ti shares some features with FXII binding to soluble polyanions but may have unique features. Inhibitors targeting FXII or FXI may be useful in mitigating Ti-induced contact activation in patients with titanium-based implants that are exposed to blood.

Pressure sore incidence and treatment in left ventricular assist device (LVAD)-equipped patients: Insights from a prospective series

INTRODUCTION

A left ventricular assistance device (LVAD) is indicated in patients with end-stage heart failure. Due to the non-physiologic blood flow, a LVAD may favor pressure sores with a devastating risk of infection. This work shows the prevalence and treatment of pressure sores in LVAD patients, to optimize their management.

MATERIAL AND METHODS

We retrospectively investigated all LVAD implantations at the Lausanne University Hospital (CHUV) from 2015 to 2019. We detected patients who developed a pressure sore and evaluated the timeline, management, and outcomes.

RESULTS

Forty-two patients benefited from LVAD, among whom 5 (12%) developed a stage III/IV pressure sore, within a mean time of 25 days. Due to their poor overall condition, 4/5 patients were treated surgically and 1/5 conservatively. Half of the patients treated with surgery had major complications requiring reoperation. After flap coverage, the mean time to healing for patients was 6 weeks.

DISCUSSION

The rapid development of deep pressure sores seen in 12% of patients may be a manifestation of the maladaptive blood flow induced by LVADs, combined with their bedridden condition. Initial signs of pressure sores should be considered seriously, as they are rapidly evolving and needing an aggressive surgical treatment whenever possible (80%). Complication rate was similar compared to standard pressure sore flap treatment. All patients benefiting from flap surgery achieved effective coverage after a mean follow-up of 24 months. No patient developed a LVAD infection.

CONCLUSION

Surgery must be considered early in this population to prevent potential device infection.

Controversies and challenges of coil embolization for intracranial aneurysm in a continuous-flow LVAD implanted patient: A case report

Background

Continuous-flow left ventricular assist device (CF-LVAD) technology has rapidly developed to support the failing heart refractory to standard medical treatments. Although the expected prognosis has improved dramatically, ischemic and hemorrhagic strokes are possible complications and the leading causes of death in the CF-LVAD population.

Case Description

We encountered a case of an unruptured large internal carotid aneurysm in a patient with a CF-LVAD. Following a detailed discussion of his expected prognosis, the risk of aneurysm rupture, and the inherited risk of aneurysm treatment, coil embolization was performed without adverse events. The patient remained recurrence-free for 2-year postoperatively.

Conclusion

This report illustrates the feasibility of coil embolization in a CF-LVAD recipient and emphasizes the necessity of vigilant consideration of whether to intervene in an intracranial aneurysm after CF-LVAD implantation. We confronted several challenges during the treatment: optimal endovascular technique, management of antithrombotic drugs, safe arterial access, desirable perioperative imaging modalities, and prevention of ischemic complications. This study aimed to share this experience.

Update on the Practical Role of Echocardiography in Selection, Implantation, and Management of Patients Requiring Left Ventricular Assist Device Therapy

PURPOSE OF REVIEW

Echocardiography is a valuable tool for management of patients with a left ventricular assist device (LVAD). We present an updated review on the practical applications of the role of echocardiography for pre- and postoperative evaluation of patients selected.

RECENT FINDINGS

The LVAD is a temporary or permanent option for patients with advanced heart failure who are unresponsive to other therapy. Use of the device has its own risks, and implantation remains a complex procedure. Transthoracic and transesophageal echocardiography are useful tools for patient evaluation and monitoring both peri- and postoperatively, as we previously presented. Assessment of left and right ventricular function, complications such as thrombus formation or intracardiac shunting, and valvular disease are all important in this assessment. This also aids in predicting postoperative complications. Placement of the device is confirmed intraoperatively, and subsequent ramp studies are used to determine optimal device settings. Right ventricular (RV) failure is the most common postoperative complication and preoperative evaluation of its function is crucial. Studies suggest that tricuspid annular plane systolic excursion, RV fractional area change, and RV global longitudinal strain are strong predictors of RV failure; LV ejection fraction, size, and end-diastolic diameter are also important markers. Aortic regurgitation and mitral stenosis must always be corrected prior to LVAD placement. However, direct visualization before and after implantation, especially to rule out potential contraindications such as thrombi, cannot be overemphasized. Ramp studies remain an integral part of device optimization and may result in greater myocardial recovery than previously realized.

A multidisciplinary approach for the emergency care of patients with left ventricular assist devices: A practical guide

The use of a left ventricular assist device (LVAD) as a bridge-to-transplantation or destination therapy to support cardiac function in patients with end-stage heart failure (HF) is increasing in all developed countries. However, the expertise needed to implant and manage patients referred for LVAD treatment is limited to a few reference centers, which are often located far from the patient's home. Although patients undergoing LVAD implantation should be permanently referred to the LVAD center for the management and follow-up of the device also after implantation, they would refer to the local healthcare service for routine assistance and urgent health issues related to the device or generic devices. Therefore, every clinician, from a bigger to a smaller center, should be prepared to manage LVAD carriers and the possible risks associated with LVAD management. Particularly, emergency treatment of patients with LVAD differs slightly from conventional emergency protocols and requires specific knowledge and a multidisciplinary approach to avoid ineffective treatment or dangerous consequences. This review aims to provide a standard protocol for managing emergency and urgency in patients with LVAD, elucidating the role of each healthcare professional and emphasizing the importance of collaboration between the emergency department, in-hospital ward, and LVAD reference center, as well as algorithms designed to ensure timely, adequate, and effective treatment to patients with LVAD.

Pre-transplant Type 2 Diabetes Mellitus Is Associated With Higher Graft Failure and Increased 5-Year Mortality After Heart Transplantation

Aims

Cardiac transplant recipients often suffer from type 2 diabetes mellitus (T2DM) but its influence on graft failure and post-transplant mortality remains unknown. The aim of this study was to investigate the long-term effects of pre-transplant T2DM in patients after heart transplantation (HTX).

Methods

This study included a total of 376 adult patients who received HTX at Heidelberg Heart Center between 01/01/2000 and 01/10/2016. HTX recipients were stratified by diagnosis of T2DM at the time of HTX. Patients with T2DM were further subdivided by hemoglobin A1c (HbA1c ≥ 7.0%). Analysis included donor and recipient data, immunosuppressive drugs, concomitant medications, post-transplant mortality, and causes of death. Five-year post-transplant mortality was further assessed by multivariate analysis (Cox regression) and Kaplan–Meier estimator.

Results

About one-third of all HTX recipients had T2DM (121 of 376 [32.2%]). Patients with T2DM showed an increased 5-year post-transplant mortality (41.3% versus 29.8%; P = 0.027) and had a higher percentage of death due to graft failure (14.9% versus 7.8%; P = 0.035). Multivariate analysis showed T2DM (HR: 1.563; 95% CI: 1.053–2.319; P = 0.027) as an independent risk factor for 5-year mortality after HTX. Kaplan–Meier analysis showed a significantly better 5-year post-transplant survival of patients with T2DM and a HbA1c < 7.0% than patients with T2DM and a HbA1c ≥ 7.0% (68.7% versus 46.3%; P = 0.008) emphasizing the clinical relevance of a well-controlled T2DM in HTX recipients.

Conclusion

Pre-transplant T2DM is associated with higher graft failure and increased 5-year mortality after HTX.

Retrospective Review of Secondary Prevention Strategies for Gastrointestinal Bleeding and Associated Clinical Outcomes in Left Ventricular Assist Device Patients

BACKGROUND

Gastrointestinal bleeding (GIB) is one of the most common bleeding complications associated with Left Ventricular Assist Devices (LVAD). Currently, there is no strong evidence or clear guidance for which secondary GIB prophylaxis strategy should be implemented after the discontinuation of aspirin.

METHODS

Our single-center study describes the outcomes of 26 LVAD patients who experienced a total of 49 GIB events, these individuals were either in Group-1) lower INR target range or Group-2) lower INR target plus a hemostatic agent as the secondary prophylaxis strategy. Each GIB event was considered an independent event. Outcomes assessed were bleeding reoccurrence rates, time to next GIB, acute GIB strategies, GIB-free days, thromboembolic events, survival, coagulation, and hematologic parameters.

RESULTS

GIB reoccurrence rates were not statistically different, Group-1) 9 (40.9%) vs Group-2) 15 (55.6%), p = 0.308. Danazol was utilized 81.5% of the time as the designated hemostatic agent. Additionally, no significant differences were observed with all of our secondary outcome measures for bleeding, ischemic events, or survival.

CONCLUSION

While our study was not powered to assess the clinical outcomes related to survival and thromboembolic events, no discernable increased risk of ischemic events including pump thrombosis was observed. Our data suggest that a lower INR target range plus danazol does not confer any additional benefit over a lower INR target range only approach. The results of this report are hypothesis-generating and additional studies are warranted to elucidate the optimal antithrombotic strategy and role of hemostatic agents in reducing the risk of recurrent GIB events.

Heart transplant recipient 1-year outcomes during the COVID-19 pandemic

The COVID‐19 pandemic initially brought forth considerable challenges to the field of heart transplantation. To prevent the spread of the virus and protect immunocompromised recipients, our center made the following modifications to post‐transplant outpatient management: eliminating early coronary angiograms, video visits for postoperative months 7, 9, and 11, and home blood draws for immunosuppression adjustments. To assess if these changes have impacted patient outcomes, the current study examines 1‐year outcomes for patients transplanted during the pandemic. Between March and September 2020, we assessed 50 heart transplant patients transplanted during the pandemic. These patients were compared to patients who were transplanted during the same months between 2011 and 2019 (n = 482). Endpoints included subsequent 1‐year survival, freedom from cardiac allograft vasculopathy, any‐treated rejection, acute cellular rejection, antibody‐mediated rejection, nonfatal major adverse cardiac events (NF‐MACE), and hospital and ICU length of stay. Patients transplanted during the pandemic had similar 1‐year endpoints compared to those of patients transplanted from years prior apart from 1‐year freedom from NF‐MACE which was significantly higher for patients transplanted during the pandemic. Despite necessary changes being made to outpatient management of heart transplant recipients, heart transplantation continues to be safe and effective with similar 1‐year outcomes to years prior.

Apixaban: Alternative Anticoagulation for HeartMate 3 Ventricular Assist Device

Patients with left ventricular assist devices currently require long-term anticoagulation with warfarin. Warfarin requires frequent blood tests and is associated with adverse events when not in the therapeutic range. Apixaban is a possible alternative that is potentially better for compliance and requires no additional testing. The purpose of this study was to compare adverse events in patients with a HeartMate 3 LVAD receiving apixaban versus warfarin. Thirty-five patients underwent HM3 implantation between January 01, 2016 to January 31, 2021. The groups compared were apixaban (n = 15, 43%) and warfarin (n = 20, 57%). All patients received 325 mg aspirin daily. Stroke, bleeding, and death were identified as primary outcomes after LVAD implant. Univariate nonparametric statistical analysis was performed. The median duration of treatment with apixaban was 148 days (37-606 days). The groups were comparable in terms of age (56 vs. 54 years), gender (male, 85% vs. 75%), and renal function (Cr 1.5 vs. 1.4). The apixaban group had significantly higher mean pulmonary artery pressure (41 vs. 34, p = 0.03) and there were more (p < 0.05) ischemic cardiomyopathy and INTERMACS profile >3 in the warfarin group. At 6 months, thrombotic complications and death were not different between the groups. The two deaths in the apixaban group were from right heart failure. The apixaban group had clinically lower rates of bleeding complications (5% vs. 30%). The adverse events of bleeding, stroke, and death were similar in HM3 patients receiving warfarin or apixaban. Apixaban may be a safe alternative anticoagulant therapy in HM 3 LVAD patients.

Neutrophil dysfunction due to continuous mechanical shear exposure in mechanically assisted circulation in vitro

OBJECTIVE

Leukocytes play an important role in the body's immune system. The aim of this study was to assess alterations in neutrophil phenotype and function in pump-assisted circulation in vitro.

METHODS

Human blood was circulated for four hours in three circulatory flow loops with a CentriMag blood pump operated at a flow of 4.5 L/min at three rotational speeds (2100, 2800, and 4000 rpm), against three pressure heads (75, 150, and 350 mm Hg), respectively. Blood samples were collected hourly for analyses of neutrophil activation state (Mac-1, CD62L, CD162), neutrophil reactive oxygen species (ROS) production, apoptosis, and neutrophil phagocytosis.

RESULTS

Activated neutrophils indicated by both Mac-1 expression and decreased surface expression of CD62L and CD162 receptors increased with time in three loops. The highest level of neutrophil activation was observed in the loop with the highest rotational speed. Platelet-neutrophil aggregates (PNAs) progressively increased in two loops with lower rotational speeds. PNAs peaked at one hour after circulation and decreased subsequently in the loop with the highest rotational speed. Neutrophil ROS production dramatically increased at one hour after circulation and decreased subsequently in all three loops with similar levels and trends. Apoptotic neutrophils increased with time in all three loops. Neutrophil phagocytosis capacity in three loops initially elevated at one hour after circulation and decreased subsequently. Apoptosis and altered phagocytosis were dependent on rotational speed.

CONCLUSIONS

Our study revealed that the pump-assisted circulation induced neutrophil activation, apoptosis, and functional impairment. The alterations were strongly associated with pump operating condition and duration.

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.

No Association between Clinical Periodontal Conditions and Microbiological Findings on Driveline of Patients with Left-Ventricular Assist Devices (LVAD)

The aim of this retrospective study was to investigate whether there would be an association between periodontal disease parameters and positive bacterial findings at the driveline of patients with a left ventricular assist device (LVAD). Patients with an LVAD, who underwent a full oral and microbiological examination between 2016 and 2018, were included. During oral examination, periodontitis severity (stage and grade) and the periodontal inflamed surface area (PISA) were evaluated. A microbiological analysis was performed from swabs of the driveline, whereby different bacterial species were cultivated and analyzed. A total of 73 patients were included in the current study. The majority of participants (80.8%) had at least one positive bacterial finding during the study period. Most patients had a periodontitis stage of III-IV (80.9%). The determined PISA of the total group was 284.78 ± 352.29 mm². No associations were found between the periodontal disease parameters and the bacterial findings in general, the bacterial findings on the day of oral examination or the bacterial findings 12 months prior to/after the oral examination (p > 0.05). Periodontitis is not associated with cultivated microbiological findings at the driveline of patients with an LVAD and thus appears not to be a risk indicator for driveline colonization. Nevertheless, the high periodontal burden in LVAD patients underlines the need for their improved periodontal care.

Proximal ascending aorta size is associated with the incidence of de novo aortic insufficiency with left ventricular assist device

We sought to assess the impact of the aortic root geometry on developing de novo aortic insufficiency (AI) in patients undergoing left ventricular assist device (LVAD). In total, 114 patients underwent LVAD implantation between February 2016 and January 2020 were included in this study (HeartMate3 N = 68, HeartWare N = 46). Significant aortic insufficiency was defined as mild-to-moderate or greater in echocardiography. The cohort was divided into two groups; those who developed significant AI (Group AI: n = 13) and did not (Group non-AI: n = 101). The primary outcomes of interest included late survival and predictors for significant AI. The patients in Group AI were older than Group non-AI (62.6 ± 11.9 vs 51.3 ± 14.0 years, p < 0.01). The diameter of proximal ascending aorta in Group AI was larger than Group non-AI (31.0 ± 5.0 vs 27.4 ± 4.3 mm, p < 0.01). Aortic valve remained closed in 53.8% in Group AI and 36.6% in Group non-AI (p = 0.24). The late survival was not significantly different between the groups (67.1% vs 76.0% at 3 years, log rank = 0.97). The Cox hazard model showed that larger proximal ascending aortic diameter/BSA (HR 1.55, CI 1.19-2.04, p < 0.01) and not-opening aortic valve (HR 4.73, CI 1.43-16.9, p = 0.01) were independent risk factors for significant AI. The cutoff value of proximal ascending aortic diameter/BSA was 15.5 (area under curve: 0.770, sensitivity: 0.69, specificity: 0.79). Dilated proximal ascending aorta at the time of LVAD surgery and not-opening aortic valve during follow-up were associated with the incidence of de novo significant AI.

Left Ventricular Assist Device: Indication, Timing, and Management

Left ventricular assist devices (LVADs) are indicated in inotrope-dependent heart failure (HF) patients with pure or predominant LV dysfunction. Survival benefit is less clear in ambulatory, advanced HF. Timing is crucial: early, unnecessary exposure to the risks of surgery, and device-related complications (infections, stroke, and bleeding) should be weighed against the probability of dying or developing irreversible right ventricular and/or end-organ dysfunction while deferring implant. The interplay between LVAD and heart transplantation depends largely on donor availability and allocation rules. Postoperatively, quality of life depends on patients' expectations and is influenced by complications. Patients' preferences, prognosis, and alternative options-including palliation-should be openly discussed and reviewed before and after the operation.

Heart Failure Is Associated with Increased Risk of Long-Term Venous Thromboembolism

The risk of venous thromboembolism (VTE) in out-patients with heart failure (HF) in long-term period is still controversial, resulting in unclear recommendations for long-term treatment. In this analysis, we found that HF was an independent risk for VTE and pulmonary embolism but not deep vein thrombosis in long-term follow-up period. Patients with chronic HF were prone to have higher risk of VTE. This meta-analysis provided an evidence which is supportive for developing strategies for prevention of VTE in patients with HF.

Background and Objectives

Venous thromboembolism (VTE), consisting of deep vein thrombosis (DVT) and pulmonary embolism (PE), is highly prevalent in in-hospital HF patients and contributes to worse prognoses. However, the risk of VTE in out-patients with HF in long-term period is controversial. This study aimed to evaluate the associations between HF and the risk of VTE in a long-term follow-up duration.

Methods

We searched for studies investigating the risk of VTE, PE, and DVT in patients with HF before April 15, 2020, in PubMed, MEDLINE, and Embase databases. Cohort studies and post hoc analysis of RCTs were eligible for inclusion if they reported relative risk of VTE, DVT or PE in patients with HF in more than 3-month follow-up period.

Results

We identified 31 studies that enrolled over 530,641 HF patients. Overall, patients with HF were associated with an increased risk of VTE (risk ratio [RR]=1.57, 95% confidence interval [CI]=1.34–1.84) and PE (RR=2.00, 95% CI=1.38–2.89). However, the risk of DVT was not significantly increased in HF patients (RR=1.33, 95% CI=0.67–2.63). Subgroup analysis showed that patients with chronic HF (RR=1.54, 95% CI=1.32–1.80) had a higher risk of VTE than those with acute HF (RR=0.95, 95% CI=0.68–1.32).

Conclusions

In conclusion, HF was an independent risk for VTE and PE but not DVT in a long-term follow-up period. Patients with chronic HF were prone to suffer from VTE than acute HF.

Asymptomatic ventricular fibrillation in continuous flow left-ventricular assist device

Left ventricular assist devices (LVADs) have increased survival for heart failure patients. Individuals with LVADs are a growing patient population with frequent complications and Emergency Department (ED) visits. A 50-year-old female presented to the ED due to a low flow alarm on her LVAD. Upon arrival in the ED she was noted to be in ventricular fibrillation. She was defibrillated with restoration to normal sinus rhythm and was started on amiodarone. An implantable cardiac defibrillator was placed during hospital admission. Amiodarone was continued as an outpatient. Patients with continuous flow LVADs can be in dysrhythmias including ventricular tachycardia and ventricular fibrillation and remain relatively asymptomatic. We present a rare case of a patient with an LVAD and ventricular fibrillation who was completely asymptomatic in the ED.

How well do we understand pulsatility in the context of modern ventricular assist devices?

BACKGROUND

Modern ventricular assist devices (VADs) use a continuous flow design. It has been suggested that a lack of pulsatility contributes to a range of adverse outcomes including pump thrombus, gastrointestinal bleeding and stroke. To better assess the role of pulsatility in these adverse events, we first require a clear definition of 'pulsatility' in the setting of a severely impaired ventricle and a modern continuous flow VAD.

METHODS

A literature review was conducted to elucidate the understanding of pulsatility in modern VAD literature. Search engines used included PUBMED, EMBASE and the Cochrane library. Articles were appraised on three aspects: Whether they mentioned pulsatility; whether they mentioned which pulsatility measure was used and finally which methodology was used to obtain the value.

RESULTS

Of 354 articles reviewed, only 13 met our broad inclusion criteria. Of these articles, the most cited measure was pulsatility index (PI) - used by 11 of the publications. The methodology used to obtain the value was not uniform and five articles did not clearly state it. Other measures included pulse pressure and surplus haemodynamic energy. The majority of articles did not directly discuss pulsatility in the setting of patient-pump interaction.

CONCLUSION

Most publications did not provide a definition for pulsatility. In those that did, the most common measure was PI. Measuring PI was not standardised. Few papers addressed the impact of intrinsic ventricular function and arterial compliance on pulsatility. We suggest that future publications adopt a uniform definition which encompasses both patient and pump characteristics.

Left Ventricular Assist Device Multialarm Emergency: A High-Fidelity Simulation Case for Emergency Medicine Residents

INTRODUCTION

As left ventricular assist devices (LVADs) become more prevalent in the treatment of patients with end-stage heart failure, emergency physicians must become experts in the management and resuscitation of patients with LVADs. As with other high-acuity, low-occurrence scenarios, managing the unstable LVAD patient makes for an ideal topic for simulation-based resident education.

METHODS

By incorporating a high-fidelity HeartMate 3 LVAD task trainer, our program developed and executed a novel LVAD simulation activity for our emergency medicine resident physicians. In the scenario, a 65-year-old male with recent LVAD placement arrived at a community hospital with undifferentiated hypotension. Various device alarms activated during the scenario and required intervention. Ultimately, the patient was found to be in septic/hypovolemic shock and only survived with appropriate resuscitation. We implemented a postscenario survey to assess the effectiveness of the simulation activity and administered it to 27 residents.

RESULTS

Content and delivery of our simulation were found to be effective; all survey questions regarding content and delivery obtained a mean score of 4.5 or greater on a 5-point Likert scale. Residents reported an overall high level of confidence in achieving most of the skill-based learning objectives (most scores > 4.1). The two objectives with the lowest confidence ratings were troubleshooting an LVAD and its various alarms (3.8) and demonstrating the ability to assess an LVAD patient (3.9).

DISCUSSION

Our LVAD simulation activity was successful and also revealed several potential areas for future research and simulation improvement.

Overview of Ventricular Assist Devices and the Total Artificial Heart

BACKGROUND

Patients with isolated left ventricular failure may have positive outcomes after being implanted with a left ventricular assist device. Unfortunately, almost half of patients with heart failure and reduced ejection fraction also have evidence of right ventricular dysfunction. For a subset of this population with severe biventricular failure, or those who develop right ventricular dysfunction after left ventricular assist device implantation, patients may necessitate biventricular assist devices or the total artificial heart.

OBJECTIVES

This overview of mechanical circulatory support devices will enhance nurses' ability to differentiate criteria for implantation, current practice, and outcomes with a focus on durable ventricular assist devices and the total artificial heart.

METHODS

A review of the literature involved searching CINAHL and PubMed databases using keywords biventricular assist devices, total artificial heart, and durable mechanical circulatory support. Results were narrowed to articles based on adults, 18 years or older. Seventy-eight relevant articles were identified, and 8 articles compared the durable biventricular assist devices.

RESULTS

Similar patient outcomes were found when comparing the use of left ventricular assist devices as biventricular support versus the total artificial heart.

DISCUSSION

The decision to implant the appropriate durable mechanical circulatory support for a patient in biventricular failure is complex and dependent on patient factors.

Lived Experiences and Long-Term Challenges and Needs of Asian Left Ventricular Assist Device Caregivers

Background: Caregivers are essential for improved outcomes in patients living with left ventricular assist device (LVAD). There is a paucity of research on a long-term LVAD caregivers' experiences and burdens.

Objectives: The aim of this study was to explore long-term challenges and needs of LVAD caregivers in the Asian health care setting.

Design: We conducted semistructured interviews with caregivers of patients who were currently or previously living with the LVAD.

Settings/Subjects: Caregivers were recruited from the National Heart Centre Singapore.

Measurements: Interviews were conducted in English and Chinese. All interviews were transcribed verbatim and analyzed based on grounded theory. Chinese interviews were translated to English before transcription.

Results: A multiethnic and multireligious sample of 11 caregivers participated. Median caregiving duration was 45 months. Caregivers described long-term challenges that were multifaceted. Misaligned patient expectations, stigmatization and limited social resources within the family and society affected caregivers' coping. Existing gender roles and spiritual and cultural influences shaped how caregivers appraised, made meaning of caregiving, and assessed support. Long-term caregivers' needs included learning from role models, shifting perspectives, enhancing communication between patient and caregivers, advocacy efforts, and holistic medical care.

Conclusions: Gender roles as well as cultural and spiritual influences affected coping and access to support in long-term Asian LVAD caregivers. Future interventions should consider culturally relevant approaches to improve well-being and quality of life of caregivers.

Continuous-flow LVAD exchange to a different pump model: Systematic review and meta-analysis of the outcomes

Despite improved outcomes of modern continuous-flow left ventricular assist devices (CF-LVADs), device exchange is still needed for various indications. While the majority of CF-LVADs are exchanged to the same model, exchange to a different pump model is occasionally warranted. In this meta-analysis, we sought to consolidate the existing evidence to better elucidate the indications and outcomes in these cases. A comprehensive systematic search of adult patient cohorts who underwent CF-LVAD exchange to a different CF-LVAD model was performed. Study-level data from 10 studies comprising 98 patients were extracted and pooled for analysis. Mean patient age was 58 (95% CI: 48-65) and 81% were male. Indication for initial CF-LVAD was ischemic cardiomyopathy in 45% (34-57). Initial device was HeartMate II LVAD (HMII) in 93 (94.9%) and HeartWare HVAD (HW) in 5 (5.1%) patients. After mean CF-LVAD support time of 18.8 (15.2-22.4) months, exchange indications included thrombosis in 71% (43-89), infection in 21% (8-47) and device malfunction in 12% (7-21). HMII to HW exchange occurred in 53 (54.1%) patients, HMII to HeartMate III (HM3) in 32 (32.7%), and HM II to either HW or HM3 in 13 (13.2%) patients. Postoperatively, right ventricular assist device was required in 16% (8-32). Overall, 20% (8-40) of patients experienced a stroke, while HW patients had a significantly higher stroke incidence than HM3 patients (HW: 21% (8-47) vs. HM3: 5% (1-24), P < .01). Overall 30-day mortality was 10% (6-17), while HW had a significantly worse 30-day mortality than HM3 (HW: 13% (7-24) vs. HM3: 5% (1-24), P = .03). Following device exchange from a different CF-LVAD model, HM3 is associated with lower stroke and higher survival when compared to HW.

Extracorporeal membrane oxygenation-assisted emergency percutaneous treatment of left ventricular assist device graft occlusion

End‐stage heart failure is more often treated with Implantable left ventricular assist device (LVAD), even if the prolonged use may increase the risk of complications. In this case, a 51‐year‐old male patient presented to our emergency department showing acute heart failure signs and symptoms and a dramatic reduction of LVAD flow. Laboratory tests ruled out significant haemolysis, usually associated with pump thrombosis. The echocardiogram and the computed tomography were not able to clarify the correct diagnosis. We immediately placed a veno‐arterial extracorporeal membrane oxygenation, followed by a selective retrograde angiography of the pump. The images showed stenosis of the LVAD‐outflow graft, suggesting a twist. Through a hand‐made J‐tip guidewire, we performed multiple dilatations of the occlusion using peripheral balloons. Finally, we implanted an aortic coarctation covered‐stent, re‐establishing an adequate cardiac output to the patient. Our case indicates that catheter‐based approach in extracorporeal membrane oxygenation assistance provides an important therapeutic alternative to treat outflow graft stenosis, especially in the case of acutely unstable patient.

Complications of left ventricular assist devices causing high urgency status on waiting list: impact on outcome after heart transplantation

Aims

Heart transplantation (HTx) represents optimal care for advanced heart failure. Left ventricular assist devices (LVADs) are often needed as a bridge‐to‐transplant (BTT) therapy to support patients during the wait for a donor organ. Prolonged support increases the risk for LVAD complications that may affect the outcome after HTx.

Methods and results

A total of 342 patients undergoing HTx after LVAD as BTT in a 10‐year period in two German high‐volume HTx centres were retrospectively analysed. While 73 patients were transplanted without LVAD complications and with regular waiting list status (T, n = 73), the remaining 269 patients were transplanted with high urgency status (HU) and further divided with regard to the observed leading LVAD complications (infection: HU1, n = 91; thrombosis: HU2, n = 32; stroke: HU3, n = 38; right heart failure: HU4, n = 41; arrhythmia: HU5, n = 23; bleeding: HU6, n = 18; device malfunction: HU7, n = 26). Postoperative hospitalization was prolonged in patients with LVAD complications. Analyses of perioperative morbidity revealed no differences regarding primary graft dysfunction, renal failure, and neurological events except postoperative infections. Short‐term survival, as well as Kaplan–Meier survival analysis, indicated comparable results between the different study groups without disadvantages for patients with LVAD complications.

Conclusions

Left ventricular assist device therapy can impair the outcome after HTx. However, the occurrence of LVAD complications may not impact on outcome after HTx. Thus, we cannot support the prioritization or discrimination of HTx candidates according to distinct mechanical circulatory support‐associated complications. Future allocation strategies have to respect that device‐related complications may define urgency but do not impact on the outcome after HTx.

How to Manage Temporary Mechanical Circulatory Support Devices in the Critical Care Setting: Translating Physiology to the Bedside

The incidence of cardiogenic shock and the utilization of mechanical circulatory support devices are increasing in the US. In this review we discuss the pathophysiology of cardiogenic shock through basic hemodynamic and myocardial energetic principles. We also explore the commonly used platforms for temporary mechanical circulatory support, their advantages, disadvantages and practical considerations relating to implementation and management. It is through the translation of underlying physiological principles that we can attempt to maximize the clinical utility of circulatory support devices and improve outcomes in cardiogenic shock.

Patterns of emergency department utilization for LVAD patients compared with non-LVAD patients

Background

Left ventricular assist device (LVAD) patients are vulnerable to over-utilization of resources.

Methods and results

We explored the pattern of emergency department (ED) presentations of LVAD patients and their costs compared with non-LVAD heart failure patients. ED visits between 7/2008 and 7/2017 were reviewed to identify 145 LVAD patients, and 435 patients with known heart failure were selected using propensity score matching for age and sex. ED evaluation metrics, hospitalization cost, and length of stay (LOS) were analyzed. Although the most common ED presentations and their frequency differed between groups, few were LVAD specific. LVAD patients were more likely to have taken personal vehicles or be flown to the ED. They had similar times to triage, rooming, and physician evaluation compared with non-LVAD patients. However, LVAD patients were noted to have a shorter time from physician assessment to disposition (109.8 min vs. 177.0 min, p < 0.001) and, overall, LVAD patients had shorter ED LOS (6.33 vs. 9.82 hrs, p = 0.0001). For patients admitted, no significant difference was found between groups in hospital LOS (6.67 vs 6.58 days, p = 0.928) or total cost ($28,766 vs $21,524, p = 0.087).

Conclusion

Shorter disposition times without increases in LOS or costs may identify a created healthcare disparity among LVAD patients.

Innovative Left Ventricular Assist Device in High-fidelity Patient Simulator

Left ventricular assist devices (LVADs) are implantable mechanical devices that pump blood from the apex of the left ventricle to the aorta in order to assist the forward flow of blood; they are most commonly used as a bridge to transplant for patients with heart failure. As of February 2019, a total of 25,145 patients with ventricular assist devices have been reported in the Interagency Registry for Mechanically Assisted Circulatory Support (Intermacs). As this number continues to grow, more and more of these patients will inevitably be seen in the acute care setting outside of their defined LVAD center. Currently, however, LVAD emergencies represent a high-acuity low-occurrence event with limited opportunities for exposure and mastery for most physicians. Therefore, a growing need exists for emergency care providers to familiarize themselves with these devices and the management of LVAD emergencies. We present a novel model for the simulation of LVAD emergencies created through simple modifications of a Laerdal 3G Manikin.