Continuous flow left ventricular assist devices: shared care goals of monitoring and treating patients

Impact of Pulse Pressure on Acute Brain Injury in Venoarterial ECMO Patients with Cardiogenic Shock During the First 24 Hours of ECMO Cannulation: Analysis of the Extracorporeal Life Support Organization Registry

Background : Low pulse pressure (PP) in venoarterial-extracorporeal membrane oxygenation (VA-ECMO) is a marker of cardiac dysfunction and has been associated with acute brain injury (ABI) as continuous-flow centrifugal pump may lead to endothelial dysregulation. Methods : We retrospectively analyzed adults (≥18 years) on "peripheral" VA-ECMO support for cardiogenic shock in the Extracorporeal Life Support Organization Registry (1/2018-7/2023). Cubic splines were used to establish a threshold (PP≤10 mmHg at 24 hours of ECMO support) for "early low" PP. ABI included central nervous system (CNS) ischemia, intracranial hemorrhage, brain death, and seizures. Multivariable logistic regressions were performed to examine whether PP≤10 mmHg was associated with ABI. Covariates included age, sex, body mass index, pre-ECMO variables (temporary mechanical support, vasopressors, cardiac arrest), on-ECMO variables (pH, PaO 2 , PaCO 2 ), and on-ECMO complications (hemolysis, arrhythmia, renal replacement therapy). Results : Of 9,807 peripheral VA-ECMO patients (median age=57.4 years, 67% male), 8,294 (85%) had PP>10 mmHg vs. 1,513 (15%) had PP≤10 mmHg. Patients with PP≤10 mmHg experienced ABI more frequently vs. PP>10 mmHg (15% vs. 11%, p<0.001). After adjustment, PP≤10 mmHg was independently associated with ABI (adjusted odds ratio [aOR]=1.25, 95% confidence interval [CI]=1.06-1.48, p=0.01). CNS ischemia and brain death were more common in patients with PP≤10 mmHg vs. PP>10 mmHg (8% vs. 6%, p=0.008; 3% vs. 1%, p<0.001). PP≤10 mmHg was associated with CNS ischemia (aOR=1.26, 95%CI=1.02-1.56, p=0.03) but not intracranial hemorrhage (aOR=1.14, 95%CI=0.85-1.54, p=0.38). Conclusions : Early low PP (≤10 mmHg) at 24 hours of ECMO support was associated with ABI, particularly CNS ischemia, in peripheral VA-ECMO patients.

Endothelial Dysfunction in Patients with Advanced Heart Failure Treated with Levosimendan Periodic Infusion Compared with Optimal Medical Therapy: A Pilot Study

Endothelial dysfunction (ED) is frequently found in patients with heart failure (HF). Among several pharmacological agents reported to improve endothelial function, levosimendan seems to be a promising one, even though, to date, only two previously published studies have evaluated its effects on ED in these patients. The aim of our pilot study was to further investigate the role of periodic levosimendan infusion on endothelial function in patients affected by advanced HF. In this cross-sectional study, three different groups were enrolled: 20 patients with advanced HF treated with periodic levosimendan (LEVO), 20 patients with HF on optimal medical therapy (OMT), and 20 healthy subjects (control group). ED was evaluated through flow-mediated dilation (FMD) at the level of the brachial artery. The three groups presented similar ages with significant differences in gender distribution, systolic blood pressure, and chronic kidney disease (eGFR < 30 mL/min). In HF patients, ischaemic aetiology was more prevalent in the LEVO group than in the OMT group (60 vs. 40%, p < 0.001). The New York Heart Association (NYHA) functional class was worse in the LEVO group, as well as in NT-proBNP (5636.7 ± 6164.6 ng/dL and 1243.7 ± 1487.2 ng/dL, in the LEVO and OMT groups, respectively, p = 0.005). The FMD was significantly higher in the healthy control group compared to that of the OMT group (15.7 ± 6.4 vs. 9.1 ± 6.0%, p = 0.007) while it showed an intermediate value in LEVO patients (12.4 ± 7.1%) (ANOVA p = 0.010). In conclusion, levosimendan therapy seems to ameliorate endothelial dysfunction related to heart failure. Longitudinal studies in patients on periodic therapy are needed in order to confirm the long-term effects of levosimendan on ED.

Alarms and Their Outcomes in Left Ventricular Assist Device Patients

Low flow and suction alarms are provided to alert caregivers of changes in left ventricular assist device pump function but may be reset in clinical practice. We investigated the incidence and underlying causes of these alarms as well as their prognostic significance. HeartWare ventricular assist device patients (n = 113) were divided into quartiles based on their frequency of low flow and suction alarms. Survival and adverse events (thrombus, stroke, bleeding, and right heart failure) were compared between quartiles. Low flow alarms peaked in the first few months of pump support before dropping down to near negligible levels. Suction alarm frequency remained relatively constant throughout pump support. Although pump speeds (p < 0.001) and flow (p = 0.01) decreased over time, there was an increase in suction alarm frequency (p = 0.018), with no changes in low flow alarms. Patients with smaller body size (p = 0.016) and lower pump flows (p = 0.008) had higher frequencies of low flow alarms on multiple regression (p < 0.001). Patients with the highest low flow alarm frequency demonstrated poorer survival (p = 0.026). There was no relationship between suction alarm frequency and survival. There was also no relationship between either low flow or suction alarm frequency with strokes, gastrointestinal bleeds, pump thrombus, or right ventricular failure. Duration of alarm and intervention in response to the alarm was not assessed in this study. Further studies examining alarm duration and responses may inform future pump alarm algorithms.

Continuous flow left ventricular assist devices do not worsen endothelial function in subjects with chronic heart failure: a pilot study

AIMS

To evaluate endothelial function in subjects with left ventricular assist devices (LVADs), comparing them with subjects with chronic heart failure with reduced ejection fraction on the list for heart transplant (HT) and with HT patients with a normal systolic cardiac function to identify any differences.

METHODS

We enrolled 28 subjects with LVAD, 55 subjects with HT, and 42 subjects with heart failure on the transplant list. The subjects underwent a general physical examination, assessment of laboratory blood parameters, and assessment of endothelial function through flow-mediated dilation (FMD) of brachial artery.

RESULTS

The three groups were homogeneous as regards age, gender, smoke abuse, C-reactive protein (CRP) and FMD parameters (P = ns). In LVAD group percentage of FMD change showed an inverse correlation with CRP (rho: -0.5, P: 0.003), a well-known marker of inflammation and tissue damage.

CONCLUSIONS

Continuous flow related to LVAD seems to not worsen endothelial function. Endothelial function was not affected by cardiovascular risk factors (hypertension, hypercholesterolaemia, diabetes, obesity, and tobacco habit), by the functional status expressed by New York Heart Association class, by the left ventricular systolic function and by the presence or absence of ischaemic heart disease in all the populations analysed. CRP was the only factor able to influence percentage of FMD change in patient with LVAD, reinforcing the hypothesis that inflammation is the main determinant of endothelial function.

Impact of Shared Care in Remote Areas for Patients With Left Ventricular Assist Devices

OBJECTIVES

The aim of this study was to evaluate the impact of a shared-care model on outcomes in patients with left ventricular assist devices (LVADs) living in remote locations.

BACKGROUND

Health care delivery through shared-care models has been shown to improve outcomes in patients with chronic diseases. However, the impact of shared-care models on outcomes in patients with LVAD is unknown.

METHODS

LVAD recipients in the authors' program (2007 to 2018) were classified based on the levels of care provided and training and resources used: level 1, was defined as outpatient primary care without LVAD-specific care; level 2 was level 1 services and outpatient LVAD-specific care; level 3 was level 2 services and inpatient LVAD-specific care and implantation center (IC). The Kaplan-Meier method was used to compare rates of survival, bleeding, pump thrombosis, infection, neurologic events, and readmissions among levels of care.

RESULTS

A total of 336 patients were included, with 255 patients (75.9%) cared for in shared-care facilities. Median follow-up was 810 (interquartile range: 321 to 1,096) days. In comparison to patients cared for by IC, patients at levels 2 and 3 shared-care centers had similar rates of death, bleeding, neurologic events, pump thromboses, and infections. However, the rates of death, pump thromboses, and infections were higher for level 1 patients than in IC patients.

CONCLUSIONS

Shared health care is an effective strategy to deliver care to patients with LVAD living in remote locations. However, patients in shared-care facilities unable to provide LVAD-specific care are at higher risk of unfavorable outcomes. Availability of LVAD-specific care should be strongly considered during patient selection and every effort made to ensure LVAD-specific training and resources are available at shared-care facilities.

Comparative assessment of different versions of axial and centrifugal LVADs: A review

Continuous-flow left ventricular assist devices (LVADs) have gained tremendous acceptance for the treatment of end-stage heart failure patients. Among different versions, axial flow and centrifugal flow LVADs have shown remarkable potential for clinical implants. It is also very crucial to know which device serves its purpose better to treat heart failure patients. A thorough comparison of axial and centrifugal LVADs, which may guide doctors in deciding before the implant, still lacks in the literature. In this work, an assessment of axial and centrifugal LVADs has been made to suggest a better device by comparing their engineering, clinical, and technological development of design aspects. Hydrodynamic and hemodynamic aspects for both types of pumps are discussed along with their biocompatibility, bearing types, and sizes. It has been observed numerically that centrifugal LVADs perform better over axial LVADs in every engineering aspect like higher hydraulic efficiency, better characteristics curve, lesser power intake, and also lesser blood damage. However, the clinical outcomes suggest that centrifugal LVADs experience higher events of infections, renal, and respiratory dysfunction. In contrast, axial LVADs encountered higher bleeding and cardiac arrhythmia. Moreover, recent technological developments suggested that magnetic type bearings along with biocompatible coating improve the life of LVADs.

Association between splenic volume and pulsatility index in patients with left ventricular assist devices

The spleen serves as a blood volume reservoir for systemic volume regulation in heart failure (HF) patients. Changes are seen in spleen size in advanced HF patients after left ventricular assist device (LVAD) implantation. The pulsatility index (PI) is an indicator of native heart contractility with hemodynamic changes in patients using LVAD. We hypothesized that the splenic volume was associated with the PI, reflecting the hemodynamics in advanced HF patients with LVADs. Herein, we investigated the relationship between splenic volume and PI in these patients. Forty-four patients with advanced HF underwent implantation of HeartMate II^® (Abbott, Chicago, IL, USA) as a bridge to heart transplantation at the Nagoya University Hospital between October 2013 and June 2019. The data of 27 patients (21 men, median age 46 years) were analyzed retrospectively. All patients underwent blood tests, echocardiography, right heart catheterization, and computed tomography (CT). Spleen size was measured via CT volumetry; the splenic volume (median: 190 mL) correlated with right arterial pressure (r = 0.431, p = 0.025) and pulmonary capillary wedge pressure (r = 0.384, p = 0.048). On multivariate linear regression analysis, the heart rate (β = -0.452, p = 0.003), pump power (β = -0.325, p = 0.023), and splenic volume (β = 0.299, p = 0.038) were independent determinants of PI. The splenic volume was associated with PI, reflecting the cardiac preload in advanced HF patients with LVADs. Thus, spleen measurement using CT may help estimate the systemic volume status and understand the hemodynamic conditions in LVAD patients.

A longitudinal comparison of health-related quality of life in rural and urban recipients of left ventricular assist devices

Left ventricular assist devices (LVAD) are a common treatment for advanced heart failure (HF) to improve ventricular function, symptoms, and health-related quality of life (HRQOL). Many LVAD recipients travel long distances from rural areas for LVAD implantation and follow-up care. Individuals with HF in rural settings who have not undergone LVAD implantation have reported poor HRQOL. However, to date, no studies have compared HF-specific or generic HRQOL in rural and urban LVAD recipients. The purpose of this study was to compare generic and HF-specific HRQOL longitudinally from preimplantation to 1-, 3-, and 6- months postimplant in a cohort of rural and urban LVAD recipients (n = 95; rural n = 32 and urban n = 63). We measured generic HRQOL using the European Quality of Life Visual Analog Scale and HF-specific HRQOL with the quality of life domain of the Kansas City Cardiomyopathy Questionnaire (KCCQ). Latent growth curve modeling identified two phases of change in generic and HF-specific HRQOL: the initial response to LVAD between preimplantation and 1-month postimplant and the subsequent change between 1- and 6-months postimplant. Comparable improvements in generic HRQOL were noted in rural and urban LVAD recipients during both phases of change. Urban LVAD recipients had greater initial improvements in HF-specific HRQOL (KCCQ) compared with rural recipients (13.0 ± 5.6, p = .02), but subsequent improvements were similar among rural and urban recipients. Ongoing assessment of generic and HF-specific HRQOL is necessary during LVAD therapy.

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

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

Left Ventricular Assist Devices 101: Shared Care for General Cardiologists and Primary Care

Ambulatory patients with a left ventricular assist device (LVAD) are increasing in number, and so is their life expectancy. Thus, there is an increasing need for care of these patients by non-LVAD specialists, such as providers in the emergency department, urgent care centers, community-based hospitals, outpatient clinics, etc. Non-LVAD specialists will increasingly come across LVAD patients and should be equipped with the knowledge and skills to provide initial assessment and management for these complex patients. These encounters may be for LVAD-related or unrelated issues. However, there are limited data and guidelines to assist non-LVAD specialists in caring for these complex patients. The aim of our review, targeting primary care providers (both inpatient and outpatient), general cardiologists, and other providers is to describe the current status of durable LVAD therapy in adults, patient selection, management strategies, complications and to summarize current outcome data.

Adverse-Event Free Survival, Hospitalizations, and Mortality in Left Ventricular Assist Device Recipients: A Rural-Urban Cohort Comparison

BACKGROUND

The number of individuals with advanced heart failure (HF) receiving left ventricular assist devices (LVADs) is growing. Postimplantation LVAD recipients return home to both rural and urban locations. The impact of rural or urban living on postimplantation outcomes has not been adequately explored.

OBJECTIVE

This cohort study examined adverse event-free survival, hospitalization-free survival, and all-cause mortality between rural and urban LVAD recipients in the first 2 years after implantation.

METHODS

Data from LVAD recipients (N = 141) implanted at a single center in the northeastern United States were analyzed. Recipients of LVAD were designated as rural or urban by county of residence. Adverse events, hospitalizations, and survival time were examined using multivariate Cox proportional hazards models.

RESULTS

Thirty-seven percent of LVAD recipients in the cohort were rural. Two-thirds of all LVAD recipients experienced at least 1 adverse event (96/141, 68.1%). Although more urban recipients experienced adverse events, including death, rural versus urban models of both adverse events and survival were nonsignificant (adverse events: log-rank = 1.18, P = .28; hazard ratio [HR], 0.96; 95% confidence interval [CI], 0.57-1.63; P = .89; survival: log-rank =2.81, P = .09; HR, 0.45; 95% CI, 0.17-1.23; P = .12). Rural LVAD recipients experienced significantly more hospitalizations and shorter hospitalization-free survival (log-rank = 6.67, P = .009). However, the HR for survival was nonsignificant (HR, 1.5; 95% CI, 0.94-2.39; P = .08).

CONCLUSIONS

Frequent adverse events and hospitalizations are of ongoing concern for LVAD recipients. More data are necessary to understand why urban LVAD recipients may experience shorter survival time compared with rural counterparts. Hospitalization may serve as a protective factor for rural LVAD recipients.

Left ventricular assist devices in the treatment of advanced heart failure

The left ventricular assist device (LVAD) is becoming the standard of care in treating patients with advanced heart failure. This article describes available LVADs, their clinical indications, and important caveats when caring for this complex patient population.

A Cloud-Based Home Management System for Patients with a left Ventricular Assist Device: A Case Report

Since implantable left ventricular assist devices (LVAD) with smaller configurations became available for bridge-to-transplant or even destination therapy in patients with end-stage heart failure, an increasing number of patients with these devices are receiving home medical management. However, these patients may be anxious about potential complications such as pump failure, thromboembolism, and infections that may occur during home management. To provide a sense of security during home management of patients with LVAD and to establish an ideal shared-care system, we developed a patient-centered cloud-based home management system for patients with LVAD. In this case report, we describe this system and report a trial of it in a 64-year-old patient with an LVAD.

Mechanical Circulatory Support for the Failing Heart: Continuous-Flow Left Ventricular Assist Devices

BACKGROUND

Heart transplantation remains the definitive therapy for patients with advanced heart failure; however, owing to limited donor organ availability and long wait times, continuous-flow left ventricular assist devices (LVADs) have become standard therapy.

METHODS

This review summarizes the history, progression, function, and basic management of LVADs. Additionally, we provide some clinical pearls and important caveats for managing this unique patient population.

RESULTS

Currently, the most common LVADs being implanted in the United States are second- and third-generation devices, the HeartMate II (Thoratec Corp., St. Jude Medical) and the HeartWare HVAD (HeartWare International, Inc.). A newer third-generation pump, the HeartMate III (Thoratec Corp., St. Jude Medical), is designed to create an artificial pulse and is currently under investigation in the United States.

CONCLUSION

LVAD use is promising, will continue to grow, and has become standard therapy for advanced heart failure as a bridge to recovery, as destination therapy, and as a bridge to transplantation.