Chronic Left Ventricular Assist Device Research Articles

Right heart failure with left ventricular assist devices: Preoperative, perioperative and postoperative management strategies. A clinical consensus statement of the Heart Failure Association (HFA) of the ESC

AbstractRight heart failure (RHF) following implantation of a left ventricular assist device (LVAD) is a common and potentially serious condition with a wide spectrum of clinical presentations with an unfavourable effect on patient outcomes. Clinical scores that predict the occurrence of right ventricular (RV) failure have included multiple clinical, biochemical, imaging and haemodynamic parameters. However, unless the right ventricle is overtly dysfunctional with end‐organ involvement, prediction of RHF post‐LVAD implantation is, in most cases, difficult and inaccurate. For these reasons optimization of RV function in every patient is a reasonable practice aiming at preparing the right ventricle for a new and challenging haemodynamic environment after LVAD implantation. To this end, the institution of diuretics, inotropes and even temporary mechanical circulatory support may improve RV function, thereby preparing it for a better adaptation post‐LVAD implantation. Furthermore, meticulous management of patients during the perioperative and immediate postoperative period should facilitate identification of RV failure refractory to medication. When RHF occurs late during chronic LVAD support, this is associated with worse long‐term outcomes. Careful monitoring of RV function and characterization of the origination deficit should therefore continue throughout the patient's entire follow‐up. Despite the useful information provided by the echocardiogram with respect to RV function, right heart catheterization frequently offers additional support for the assessment and optimization of RV function in LVAD‐supported patients. In any patient candidate for LVAD therapy, evaluation and treatment of RV function and failure should be assessed in a multidimensional and multidisciplinary manner.

Machine Learning Multicenter Risk Model to Predict Right Ventricular Failure After Mechanical Circulatory Support

The existing models predicting right ventricular failure (RVF) after durable left ventricular assist device (LVAD) support might be limited, partly due to lack of external validation, marginal predictive power, and absence of intraoperative characteristics. To derive and validate a risk model to predict RVF after LVAD implantation. This was a hybrid prospective-retrospective multicenter cohort study conducted from April 2008 to July 2019 of patients with advanced heart failure (HF) requiring continuous-flow LVAD. The derivation cohort included patients enrolled at 5 institutions. The external validation cohort included patients enrolled at a sixth institution within the same period. Study data were analyzed October 2022 to August 2023. Study participants underwent chronic continuous-flow LVAD support. The primary outcome was RVF incidence, defined as the need for RV assist device or intravenous inotropes for greater than 14 days. Bootstrap imputation and adaptive least absolute shrinkage and selection operator variable selection techniques were used to derive a predictive model. An RVF risk calculator (STOP-RVF) was then developed and subsequently externally validated, which can provide personalized quantification of the risk for LVAD candidates. Its predictive accuracy was compared with previously published RVF scores. The derivation cohort included 798 patients (mean [SE] age, 56.1 [13.2] years; 668 male [83.7%]). The external validation cohort included 327 patients. RVF developed in 193 of 798 patients (24.2%) in the derivation cohort and 107 of 327 patients (32.7%) in the validation cohort. Preimplant variables associated with postoperative RVF included nonischemic cardiomyopathy, intra-aortic balloon pump, microaxial percutaneous left ventricular assist device/venoarterial extracorporeal membrane oxygenation, LVAD configuration, Interagency Registry for Mechanically Assisted Circulatory Support profiles 1 to 2, right atrial/pulmonary capillary wedge pressure ratio, use of angiotensin-converting enzyme inhibitors, platelet count, and serum sodium, albumin, and creatinine levels. Inclusion of intraoperative characteristics did not improve model performance. The calculator achieved a C statistic of 0.75 (95% CI, 0.71-0.79) in the derivation cohort and 0.73 (95% CI, 0.67-0.80) in the validation cohort. Cumulative survival was higher in patients composing the low-risk group (estimated <20% RVF risk) compared with those in the higher-risk groups. The STOP-RVF risk calculator exhibited a significantly better performance than commonly used risk scores proposed by Kormos et al (C statistic, 0.58; 95% CI, 0.53-0.63) and Drakos et al (C statistic, 0.62; 95% CI, 0.57-0.67). Implementing routine clinical data, this multicenter cohort study derived and validated the STOP-RVF calculator as a personalized risk assessment tool for the prediction of RVF and RVF-associated all-cause mortality.

Long-term Dalbavancin for Suppression of Gram-Positive Chronic Left Ventricular Assist Device Infections.

Infection is the leading cause of morbidity and mortality in patients with left ventricular assist devices (LVADs). Prolonged suppressive therapy should be strongly considered and is often used in patients with recurrent infections when source control cannot be achieved. Dalbavancin is a promising option in patients with LVADs requiring prolonged durations of antibiotic therapy, especially when no oral alternatives are available. This case series included 8 patients receiving dalbavancin for the long-term suppression of gram-positive infections at Emory University Hospital and Emory St Joseph's Hospital. The overall incidence of breakthrough infections occurred in 5 of the 8 patients included in the study. One patient experienced an early breakthrough infection within 1 month of dalbavancin initiation. Another experienced a breakthrough infection within 3 and 6 months of dalbavancin initiation, and the final 3 patients experienced a breakthrough infection within 6 and 12 months. The average duration of dalbavancin suppression therapy among all patients was 229 days, and no adverse effects were reported. Dalbavancin is a promising option in patients who require long-term suppression for chronic gram-positive LVAD infections, given its unique pharmacokinetic profile and excellent tissue penetration. The use of biweekly dalbavancin infusions in our 8 patients prevented infection for an extended period of time despite some of the patients not being able to consistently receive infusions. Larger studies are needed to determine the efficacy and safety of using dalbavancin for long-term suppression of gram-positive LVAD infections.

Exercise oscillatory ventilation in patients with advanced heart failure with and without left ventricular assist device.

Exercise oscillatory ventilation (EOV), indicating pathological fluctuations on pulmonary arterial pressure, is associated with mortality in patients with heart failure (HF). Whether left ventricular assist device (LVAD)-induced ventricular unloading can reverse EOV and may prevent short-term rehospitalization has not been investigated. We performed a retrospective single-center in- and outpatient analysis of patients with (n=20, LVAD) and without (n=27, HF) circulatory support and reduced ejection fraction (EF, 22.8 ± 7.9%). The association of cardiopulmonary exercise testing (CPET) variables and 3 months-rehospitalization (3MR) as a primary outcome was analyzed. Furthermore, CPET variables were compared regarding the presence of EOV (+/-). Lower VO2peak (11.6 ± 4.9ml/kg/min vs. 14.4 ± 4.3ml/kg/min, p=0.039), lower increase of PETCO2 (CI=0.049-1.127; p=0.068), and higher VE/VCO2 (43.8 ± 9.5 vs. 38.3 ± 10.6; p=0.069) were associated with 3MR. Flattening of O2 pulse (CI=0.139-2.379; p=0.487) had no impact on 3MR. EOV was present in 59.5% (n=28/47) of patients, without a significant difference between LVAD and HF patients (p=0.959). Patients with HF/EOV+ demonstrated significantly lower VO2peak compared with HF/EOV- (p=0.039). LVAD/EOV+ displayed significantly lower EF (p=0.004) and fewer aortic valve opening than LVAD/EOV- (p=0.027). Lower VO2peak , but not EOV, was associated with 3MR. EOV occurred at a similar rate in LVAD and HF patients, which may illustrate insufficient unloading during exercise in chronic LVAD therapy and may contribute to the limited exercise capacity following LVAD implantation. Simultaneous CPET and right heart catheterization studies are needed to elucidate whether EOV may serve as a non-invasive predictor of insufficient LV unloading necessitating LVAD reprograming.

Feasibility of high-intensity interval training in patients with left ventricular assist devices: a pilot study.

AimsPatients with left ventricular assist device (LVAD) suffer from persistent exercise limitation despite improvement of their heart failure syndrome. Exercise training (ET) programmes to improve aerobic capacity have shown modest efficacy. High‐intensity interval training (HIIT), as an alternative to moderate continuous training, has not been systematically tested in this population. We examine the feasibility of a short, personalized HIIT programme in patients with LVAD and describe its effects on aerobic capacity and left ventricular remodelling.Methods and resultsPatients on durable LVAD support were prospectively enrolled in a 15‐session, 5 week HIIT programme. Turndown echocardiogram, Kansas City Cardiomyopathy Questionnaire, and cardiopulmonary exercise test were performed before and after HIIT. Training workloads for each subject were based on pretraining peak cardiopulmonary exercise test work rate (W). Percentage of prescribed training workload completed and adverse events were recorded for each subject. Fifteen subjects were enrolled [10 men, age = 51 (29–71) years, HeartMate II = 12, HeartMate 3 = 3, and time on LVAD = 18 (3–64) months]. Twelve completed post‐training testing. HIIT was well tolerated, and 90% (inter‐quartile range: 78, 99%) of the prescribed workload (W) was completed with no major adverse events. Improvements were seen in aV̇O2 at ventilatory threshold [7.1 (6.5, 9.1) to 8.5 (7.7, 9.3) mL/kg/min, P = 0.04], work rate at ventilatory threshold [44 (14, 54) to 55 (21, 66) W, P = 0.05], and left ventricular end‐diastolic volume [168 (144, 216) to 159 (124, 212) mL, n = 7, P = 0.02]. HIIT had no effect on maximal oxygen consumption (V̇O2peak) or Kansas City Cardiomyopathy Questionnaire score.ConclusionsCardiopulmonary exercise test‐guided HIIT is feasible and can improve submaximal aerobic capacity in stable patients with chronic LVAD support. Further studies are needed on its effects on the myocardium and its potential role in cardiac rehabilitation programmes.

Anesthesia in Patient with Left Ventricular Assist Device Support. A Case Report.

Background; Left ventricular assist device (LVAD) implantation is not only a bridge-to-transplantation option for patients awaiting a donor's heart, but is often used as bridge-to-destination therapy in patients unsuitable for transplantation for various reasons. Device infection remains a threatening complication, which may lead to prolonged hospitalization, need to devise exchange, urgent transplantation, and even death of the patient. Infections with multidrug-resistant (MDR) organisms pose major difficulties for eradication therapy. Especially patients who are subject to continuous hospital treatments risk contamination or change of resistances spectrum. Gold standard therapy of certain organisms often fails to eradicate surface-associated colonization of implanted devices such as cardiovascular implants, while failed eradication leads to numerous complications and an increased mortality rate among the affected patients. Device infections through multidrug-resistant bacteria, such as MRSA, are often resistant even to first-line antibiotics, due to extended resistance spectrum and reduce tissue penetration in scar tissue after multiple surgical procedures. In addition, a solid biofilm on devices is often impenetrable even for suitable antibiotics because of the isolating nature of biofilms.&#x0D; Case presentation; A 48-year-old patient 72 kg, height 172 cm with dilated cardiomyopathy, his course was complicated by pump failure requiring LVAD HeartMate III placement 3 years (Milan Italy). The parameters of the LVAD pump were determined for the patient from the moment of the Pump speed 5300 rpm Flow 4.4 lpm was set. The patient performed moderate activity under normal conditions. The patient regularly took Coumadin to keep the recommended INR levels at the recommended target values ​​2.5. At the site of the exit of the cavity from the skin in the region of the right hypochondrium, there was an infection that for a long time was treated with various schemes with ambulatory antibiotics&#x0D; Conclusions; In the present case we showed that successful eradication of a chronic LVAD driveline infection was only possible when approached both surgically and conservatively. It is important to note that a good knowledge of the physiopathology of heart failure, the widest possible information on the treatment of heart failure with the help of LVAD implantation is very important in the treatment and survival of these patients.

Treatment of Chronic Left Ventricular Assist Device Infection with Local Application of Bacteriophages

Left ventricular assist device (LVAD)associated infections represent a major complication during long-term support. Additionally, during prolonged antibiotic treatment, antimicrobial resistance and adverse effects may occur. Therefore, alternative anti-bacterial approaches should be evaluated. We report about the successful treatment of two patients with chronic recurrent LVAD pump-associated infections after local application of bacteriophages as adjunct to standard surgical and antimicrobial treatment. No side effects occurred. At the follow up visits six/nine months later the surgical sites showed no signs of infection. Our experience justifies further investigation into the indication and the therapeutic success of bacteriophages in LVAD-associated infections.

Magnitude and Time Course of Left Atrial Remodeling Changes in Patients Undergoing Chronic Left Ventricular Assist Device Support

Although left ventricular (LV) reverse remodeling has been described in patients with left ventricular assist devices (LVADs), little is known about left atrial (LA) structural and functional changes. Echocardiographic parameters were obtained at pre-LVAD implant and following 1, 3, and 6 months of LVAD support. Favorable LV structural and functional response following LVAD support (i.e. Responders) was defined using previously published criteria. Structural and functional indices specific to LA such as LA volume index (LAVI) and LA total emptying fraction (LATEF) were compared in eighteen Responders versus twenty Non-Responders. Statistical comparison of quantitative data was performed using 2-tailed Wilcoxon signed-rank test for paired samples and categorical data were compared using Fisher's exact test. The magnitude and time course of functional changes as reflected by the LVEF and LATEF in Responders and Non-Responders are depicted in Figure 1A and 1B. LA remodeling structural changes over time in Responders and Non-Responders are depicted in Figure 1C. Patients experiencing post-LVAD favorable LV functional response had significantly better LA remodeling structural and functional indices before LVAD implantation and further improved those early after the initiation of LV mechanical support. LA reverse remodeling studies with longer follow-up and correlation with post LVAD-weaning patient outcomes are warranted.

An Initial Experience from a Single Centre with Oral Milrinone in Patients Supported with a Left Ventricular Assist Device

Milrinone is a phosphodiesterase III inhibitor used as an inodilator in patients with right ventricular (RV) failure. Oral milrinone may offer an alternative to patients with refractory RV dysfunction supported with left ventricular assist devices (LVAD). We reviewed all patients supported on an LVAD commenced on oral milrinone for a refractory right ventricular failure who were maintained using therapeutic drug monitoring in the community (range 100-300 ng/ml). Available haemodynamic data and outcomes were assessed. Seven patients (Median Age 50 (IQR 48-54), Male 6/7) on chronic LVAD support with refractory RV failure, were commenced on oral Milrinone for persistently raised Pulmonary Vascular Resistance (PVR) or recurrent episodes of decompensated heart failure. The median duration of milrinone therapy was 117(IQR 59-221) days. Outpatient monitoring of milrinone levels was feasible and showed overall Median level was 175(111-256) ng/ml. There were no adverse events related to milrinone and in particular, there were no arrhythmias recorded. One patient died due to worsening heart failure; two patients were transplanted but one died during the post-op period. Of the surviving patients, matched right heart catheterisation data were available for 3 patients (see table) which showed some evidence of improved PVR and Cardiac Index (CI). In this limited cohort, oral milrinone appears to be tolerated, safe and feasible to maintain appropriate therapeutic levels in this population in the community. This therapy may offer additional cardiovascular support for patients deteriorating on maximal LVAD support who are not immediate candidates for cardiac transplantation.

Impact of Hemodynamic Ramp Test-Guided HVAD RPM and Medication Adjustments on Exercise Tolerance and Quality of Life: The RAMP-IT-UP Multicenter Study

Summary of Objectives Ramp tests are used to optimize left ventricular assist device (LVAD) speed and tailor medical therapy. The addition of invasive hemodynamics to the ramp test has the potential to provide further information that will improve patient management. The aim of this study is to investigate the effects of a hemodynamic-guided approach to LVAD management on clinical outcomes, including exercise capacity and quality of life measures. Methods RAMP-IT-UP is a multi-center, randomized trial comparing two management strategies for LVAD patients: a hemodynamic approach employing a hemodynamic ramp study to optimize LVAD speed and medical therapy (HR arm) and a standard of care approach employing transthoracic echocardiography (TTE) for optimization of LVAD speed and medical therapy (TTE arm). This study enrolled 41 patients (22 in HR arm, 19 in TTE arm) who had an HVAD LVAD and were 1-3 months post-implantation. All patients will be followed for six months after enrollment. Primary endpoints are changes in the 6-minute walk test, New York Heart Association Class and Kansas City Cardiomyopathy Questionnaire score. Exploratory endpoints will include the incidence of clinical events (mortality, heart failure admission, arrhythmias, gastrointestinal bleeding, stroke, pump thrombosis, aortic insufficiency and driveline infection). The analysis will include 6-month results for the full study cohort. The last patient was enrolled in September 2018, and will complete follow-up in March 2019. Endpoints This is the first randomized study of two different clinical management strategies for chronic LVAD patients. This study will evaluate the benefits of a hemodynamic-guided approach on quality of life and outcomes of LVAD patients. (Funded by Medtronic; ClinicalTrials.gov Number, NCT03021239)

Sheet-Like Remodeling of the Transverse Tubular System in Human Heart Failure Impairs Excitation-Contraction Coupling and Functional Recovery by Mechanical Unloading.

Cardiac recovery in response to mechanical unloading by left ventricular assist devices (LVADs) has been demonstrated in subgroups of patients with chronic heart failure (HF). Hallmarks of HF are depletion and disorganization of the transverse tubular system (t-system) in cardiomyocytes. Here, we investigated remodeling of the t-system in human end-stage HF and its role in cardiac recovery. Left ventricular biopsies were obtained from 5 donors and 26 patients with chronic HF undergoing implantation of LVADs. Three-dimensional confocal microscopy and computational image analysis were applied to assess t-system structure, density, and distance of ryanodine receptor clusters to the sarcolemma, including the t-system. Recovery of cardiac function in response to mechanical unloading was assessed by echocardiography during turndown of the LVAD. The majority of HF myocytes showed remarkable t-system remodeling, particularly sheet-like invaginations of the sarcolemma. Circularity of t-system components was decreased in HF versus controls (0.37±0.01 versus 0.46±0.02; P<0.01), and the volume/length ratio was increased in HF (0.36±0.01 versus 0.25±0.02 µm2; P<0.0001). T-system density was reduced in HF, leading to increased ryanodine receptor-sarcolemma distances (0.96±0.05 versus 0.64±0.1 µm; P<0.01). Low ryanodine receptor-sarcolemma distances at the time of LVAD implantation predicted high post-LVAD left ventricular ejection fractions (P<0.01) and ejection fraction increases during unloading (P<0.01). Ejection fraction in patients with pre-LVAD ryanodine receptor-sarcolemma distances >1 µm did not improve after mechanical unloading. In addition, calcium transients were recorded in field-stimulated isolated human cardiomyocytes and analyzed with respect to local t-system density. Calcium release in HF myocytes was restricted to regions proximal to the sarcolemma. Local calcium upstroke was delayed (23.9±4.9 versus 10.3±1.7 milliseconds; P<0.05) and more asynchronous (18.1±1.5 versus 8.9±2.2 milliseconds; P<0.01) in HF cells with low t-system density versus cells with high t-system density. The t-system in end-stage human HF presents a characteristic novel phenotype consisting of sheet-like invaginations of the sarcolemma. Our results suggest that the remodeled t-system impairs excitation-contraction coupling and functional recovery during chronic LVAD unloading. An intact t-system at the time of LVAD implantation may constitute a precondition and predictor for functional cardiac recovery after mechanical unloading.

Right Ventricular Systolic and Diastolic Function as Assessed by Speckle-Tracking Echocardiography Improve with Long-Term Left Ventricular Assist Device Support

Right ventricular (RV) failure is a major cause of morbidity and mortality after left ventricular assist device (LVAD) implantation. As a LVAD primarily supports the left ventricle, it is unknown whether RV pathology progresses over time leading to deterioration in RV function among patients chronically supported with a LVAD. RV longitudinal strain and strain rate as measured by speckle-tracking echocardiography provide a more sensitive, reproducible, and quantitative assessment of RV systolic and diastolic function than conventional echocardiography. Since LVADs decrease left sided filling pressure, reduce pulmonary pressure, and reduce RV afterload we hypothesized that RV systolic and diastolic function would remain stable or even improve after prolonged continuous-flow LVAD support. Echocardiograms were retrospectively reviewed from before and after implantation of a HeartMate II LVAD between 2006 and 2013 at a single center. Patients who had a baseline echocardiogram before LVAD that was performed off inotropes and a follow up echocardiogram after at least 2 months of LVAD support were included in the analysis. Patients were excluded if they required a RV assist device, had a LVAD malfunction, or had poor echocardiographic visualization of the RV endocardium. The speckle-tracking analysis software Velocity Vector Imaging (Siemens Medical) was used to calculate global RV longitudinal systolic strain, strain rate, and diastolic strain rate. Paired t-tests compared measures at baseline before LVAD to the time of maximal follow up after LVAD implantation. Of the 75 LVAD patients screened, 32 had a baseline echocardiogram off inotropes before LVAD along with a paired echocardiogram at least 2 months after LVAD implantation. 15 patients met exclusion criteria, leaving an analysis cohort of 17 patients with a mean duration of LVAD support at the time of the follow up echocardiogram of 271±129 days. Global RV longitudinal strain improved in 12 of 17 patients (70%) with the average RV strain decreasing from -7.9±2.3% before to -9.8±3.4% after LVAD (p=0.034). Similarly, RV longitudinal systolic strain rate improved in 11 patients (64%) with the average RV systolic strain rate decreasing from -0.67±0.24%/sec before to -0.99±0.35%/sec after LVAD (p=0.002). Finally RV longitudinal diastolic strain rate improved in 14 patients (82%) with the average RV diastolic strain rate increasing from 0.77±0.33%/sec before to 0.99±0.33%/sec after LVAD (p=0.029). Among LVAD patients who did not require a RV assist device, RV systolic and diastolic function as determined by speckle-tracking echocardiography improved in the majority of patients during chronic LVAD support. This suggests that LVADs prevent progression of RV dysfunction in this group of patients and emphasizes the need for strategies for temporary support of the failing RV in the initial period after LVAD implantation to allow for long term stabilization and improvement in RV function.

Effects of the left ventricular assist device on the compliance and distensibility of the carotid artery

We investigated the impact of continuous-flow left ventricular assist devices (LVAD) on the carotid elastic properties. Carotid artery parameters (diameter distensibility (DD), cross-sectional distensibility (CSD), diameter compliance (DC), cross-sectional compliance (CSC), and incremental elastic modulus (IEM)) were measured in a cross-sectional study using a standard ultrasound with a 10-MHz linear array probe. Measurements (mean ± SEM) were made in separate groups at various clinical time points: prior to LVAD surgery (baseline; 13 male/3 female; age 48 ± 3 years), 1 week following LVAD placement (acute; 12 male/2 female; age 47 ± 3 years), approximately 24 weeks following LVAD surgery (chronic; 13 male/2 female; age 52 ± 3 years), and in a group of healthy subjects (controls; 9 male/1 female; age 51 ± 4 years). Distensibility properties were lower (P < 0.05) in the acute (DD 2.3 % ± 0.4 %; CSD 4.7 % ± 0.8 %) and chronic (DD 2.2 % ± 0.4 %; CSD 4.5 ± 0.9 %) compared with the baseline (DD 5.9 % ± 0.7 %; CSD 12.2 % ± 1.5 %) and control (DD 5.8 % ± 0.6 %; CSD 11.9 % ± 1.3 %) groups. Compliance properties were lower (P < 0.05) in the chronic (DC 4.4 ± 0.7 mm/mmHg × 10(-3); CSC 1.2 ± 0.2 mmHg(-1) × 10(-3)) compared with acute (DC 9.0 ± 1.6 mm/mmHg × 10(-3); CSC 2.6 ± 0.4 mmHg(-1) × 10(-3)) and baseline (DC 11.1 ± 1.1 mm/mmHg × 10(-3); CSC 3.3 ± 0.4 mmHg(-1) × 10(-3)) groups. The compliance properties in the control (DC 8.3 ± 0.8 mm/mmHg × 10(-3); CSC 2.4 ± 0.2 mmHg(-1) × 10(-3)) group were not different from any of the patient groups. The IEM was higher (P < 0.05) in the chronic (6908 ± 1269 mmHg) compared with acute (2739 ± 412 mmHg), baseline (1849 ± 177 mmHg), and control (2349 ± 241 mmHg) groups. Chronic continuous-flow LVAD support is associated with lower carotid artery compliance and distensibility, which may place further strain on the left ventricle.

Superior Mesenteric Artery Mycotic Aneurysm in Patients With Left Ventricular Assist Device Support and Intravenous Drug Abuse

Mycotic aneurysm of the superior mesenteric artery (SMA) is one of the complications associated with infective endocarditis. However, there are no previous case reports in the literature describing mycotic SMA aneurysm after left ventricular assist device (LVAD) implantation. We describe the case of a 31-year-old male diagnosed with congestive heart failure due to nonischemic dilated cardiomyopathy who underwent LVAD implantation for bridge to heart transplantation. The postoperative course was uneventful, and the patient was maintained on anticoagulation and antiplatelet therapy. There were no signs of pump failure or device-related infections. However, 7 months post-LVAD support, the patient complained of abdominal symptoms (nausea and vomiting) with low-grade fever. Computed tomography identified an aneurysmal change of the SMA (2.2 × 1.8 cm). There was no evidence of thrombus or septic vegetation inside the heart. Aneurysm and segmental small bowel resection was performed. Pathological study revealed typical findings of mycotic aneurysm with significant infiltration of inflammatory cells. The patient, however, expired due to concurrent brain hemorrhage. Postmortem study indicated no sign of pump thrombus or septic emboli inside the pump or inflow/outflow conduit. This case report presents a rare mycotic aneurysm that developed in the SMA after chronic LVAD support.

Left ventricular assist device management in patients chronically supported for advanced heart failure

This review summarizes management strategies to reduce morbidity and mortality in heart failure patients supported chronically with implantable left ventricular assist devices (LVADs). As the population of patients supported with long-term LVADs has grown, patient selection, operative technique, and patient management strategies have been refined, leading to improved outcomes. This review summarizes recent findings on LVAD candidate selection, and discusses outpatient strategies to optimize device performance and heart failure management. It also reviews important device complications that warrant close outpatient monitoring. Managing patients on chronic LVAD support requires regular patient follow-up, multidisciplinary care teams, and frequent laboratory and echocardiographic surveillance to ensure optimal outcomes.

Hemodynamic Responses to Continuous versus Pulsatile Mechanical Unloading of the Failing Left Ventricle

Debate exists regarding the merits and limitations of continuous versus pulsatile flow mechanical circulatory support. To characterize the hemodynamic differences between each mode of support, we investigated the acute effects of continuous versus pulsatile unloading of the failing left ventricle in a bovine model. Heart failure was induced in male calves (n = 14). During an acute study, animals were instrumented through thoracotomy for hemodynamic measurement. A continuous flow (n = 8) and/or pulsatile flow (n = 8) left ventricular assist device (LVAD) was implanted and studied during maximum support ( approximately 5 L/min) and moderate support ( approximately 2-3 L/min) modes. Pulse pressure (PP), surplus hemodynamic energy (SHE), and (energy equivalent pressure [EEP]/mean aortic pressure (MAP) - 1) x 100% were derived to characterize hemodynamic energy profiles during the different support modes. Standard hemodynamic parameters of cardiac performance were also derived. Data were analyzed by repeated measures one-way analysis of variance within groups and unpaired Student's t-tests across groups. During maximum and moderate continuous unloading, PP, SHE, and (EEP/MAP - 1) x 100% were significantly decreased compared with baseline and compared with pulsatile unloading. As a result, continuous unloading significantly altered left ventricular peak systolic pressure, aortic systolic and diastolic pressure, +/-dP/dt, and rate x pressure product, whereas pulsatile unloading preserved a normal profile of physiologic values. As continuous unloading increased, the pressure-volume relationship collapsed, and the aortic valve remained closed. In contrast, as pulsatile unloading increased, a comparable decrease in left ventricular volumes was noted. However, a normal range of left ventricular pressures was preserved. Continuous unloading deranged the physiologic profile of myocardial and vascular hemodynamic energy utilization, whereas pulsatile unloading preserved more normal physiologic values. These findings may have important implications for chronic LVAD therapy.

Patient Satisfaction With the External Equipment of Implantable Left Ventricular Assist Devices

Patient satisfaction with left ventricular assist device (LVAD) external equipment has not yet been reported. We aimed to evaluate the quality of two different systems based on patients' perspective and its interrelationship with quality of life. Differential assessment of the HeartMate II axial flow pump (n = 17; Thoratec, Pleasanton, CA, USA) and the HVAD centrifugal pump (n = 10; HeartWare, Inc., Miramar, FL, USA) was obtained from 27 outpatients by a questionnaire 2 months to 2.9 years after device implantation. In addition, a health-related quality of life questionnaire (Short Form-36 [SF-36]) was completed. Overall patients' satisfaction was high. Severe limitations were attributed to the loudness of the power base unit in HeartMate II patients (P = 0.00), and HVAD patients were dissatisfied by the length of the driveline (P = 0.02). Between HVAD and HeartMate II patients, no significant differences in the quality of life (assessed by SF-36) were reported. While the overall satisfaction of outpatients on LVAD support was high, differences between the systems were found. Patients' perspectives may have an important impact on future modification of external components. Ultimately, this may also contribute to an improvement in the quality of life of chronic LVAD patients.

Acquired von Willebrand Syndrome in Patients With an Axial Flow Left Ventricular Assist Device

Rotary blood pumps used as left ventricular assist devices (LVADs) allow for long-term support and may become suitable alternatives to heart transplantation. Effects of this technology on the coagulation system are not completely understood, leading to controversial anticoagulation protocols. Thus, we investigated the primary hemostasis in patients with chronic LVAD therapy. Twenty-six outpatients received axial flow LVAD (HeartMate II; Thoratec) for a median support time of 4.5 months. In a cross-sectional protocol, platelet aggregation in response to ADP and epinephrine, von Willebrand antigen (vWF:AG), and collagen-binding capacity (vWF:CB) were obtained. Von Willebrand factor (vWF) multimer analyses were performed, and patients were screened for bleeding events. This analysis was repeated after removal of the device for transplantation or recovery (n=12) and after a median of 15.5 months in ongoing patients (n=11). In all patients on devices, severe impairment of platelet aggregation as well as a loss of large vWF multimers were found. In 10 patients, a decreased vWF:CB/vWF:AG ratio was observed. Bleeding episodes occurred with an incidence of 0.17 per patient-year. After removal of the device, normal patterns of platelet aggregation, multimer analysis, and vWF:CB/vWF:AG ratio were recorded. In the second analysis of ongoing patients, impairment of platelet aggregation and loss of large vWF multimers were verified. A diagnosis of von Willebrand syndrome type 2 was established in all patients after LVAD implantation, and bleeding events confirmed this finding. Reversibility of this condition was found after removal of the device.

Acquired Aortic Cusp Fusion After Chronic Left Ventricular Assist Device Support

Explanted hearts from patients with chronic left ventricular assist device (LVAD) support have shown the presence of aortic cusp fusion, which results in valvular stenosis and may complicate weaning of a LVAD. This is the first report of aortic cusp fusion diagnosed solely by transesophageal echocardiography (TEE) in vivo in a patient on chronic LVAD support. Under intraoperative TEE guidance, a 41-year-old woman underwent an attempted explantation of a LVAD, which had been implanted 8 months before for dilated cardiomyopathy. When LVAD support was discontinued, previously normal left ventricular function deteriorated, and aortic stenosis from aortic valve cusp fusion was documented by TEE. The explantation procedure was abandoned. This case demonstrates the utility of intraoperative TEE in the evaluation of aortic valvular anatomy and function in patients wtih chronic LVAD support.

Left Ventricular Assist Device Malfunction: An Approach to Diagnosis by Echocardiography

A protocol using transthoracic echocardiography was designed to diagnose the common malfunctions of patients on chronic support with a left ventricular assist device (LVAD). Mechanical circulatory support, primarily with a LVAD, is increasingly used for treatment of advanced heart failure as a bridge to transplant and for long-term treatment of heart failure. The LVAD dysfunction is a recognized complication. To date, no studies have defined the role of transthoracic echocardiography in evaluating long-term mechanical complications of chronic LVAD support. Transthoracic echocardiography was used in a protocol designed to detect the common types of mechanical malfunction. Patients were followed up with serial echocardiograms, and clinical validations were made with findings from a catheter-based protocol and inspection at the time of cardiac transplant or corrective surgery. Thirty-two patients with 44 LVADs were followed up during a four-year period using this protocol that correctly identified 11 patients with inflow valve regurgitation, 2 with intermittent inflow conduit obstruction, 1 with severe kinking of the outflow graft, and 9 with new insufficiency of the native aortic valve. As LVAD use for end-stage heart failure becomes widespread, and durations of support are extended, dysfunction will be increasingly prevalent. Transthoracic echocardiography provides a practical method to accurately identify the causes of mechanical dysfunction with patients on chronic LVAD support.