HeartMate 3 Snoopy: Noninvasive cardiovascular diagnosis of patients with fully magnetically levitated blood pumps during echocardiographic speed ramp tests and Valsalva maneuvers.

PURPOSE: The HeartMate 3 (HM3) left ventricular assist device (LVAD) has demonstrated excellent clinical outcomes; however, pump speed optimization is challenging with the available HM3 monitoring. Therefore, this study reports on clinical HM3 parameters collected with a noninvasive HM3 monitoring system (HM3 Snoopy) during echocardiographic speed ramp tests and Valsalva maneuvers. METHODS: In this prospective, single-center study, the HM3 data communication between the controller and pump was recorded with a novel data acquisition system. Twelve pump parameters sampled every second (1 Hz) and clinical assessments (echocardiography, electrocardiogram (ECG), and blood pressure measurement) during speed ramp tests were analyzed using Pearson's correlation (r, median [IQR]). The cause for the occurrence of pulsatility index (PI)-events during ramp speed tests and valsalva maneuvers was investigated. RESULTS: In 24 patients (age: 58.9 ± 8.8 years, body mass index: 28.1 ± 5.1 kg/m2, female: 20.8%), 35 speed ramp tests were performed with speed changes in the range of ±1000 rpm from a baseline speed of 5443 ± 244 rpm. Eight HM3 pump parameters from estimated flow, motor current, and LVAD speed together with blood pressure showed positive collinearities (r = 0.9 [0.1]). Negative collinearities were observed for pump flow pulsatility, pulsatility index, rotor noise, and left ventricular diameters (r = -0.8 [0.1]), whereas rotor displacement and heartrate showed absence of collinearities (r = -0.1 [0.08]). CONCLUSIONS: In this study, the HM3 Snoopy was successfully used to acquire more parameters from the HM3 at a higher sampling rate. Analysis of HM3 per-second data provide additional clinical diagnostic information on heart-pump interactions and cause of PI-events.

Insights into the daily life of ventricular assist device coordinators: Outcome of an international questionnaire.

BACKGROUND: As the incidence of heart failure in developed countries is on the rise, mechanical circulatory support (MCS) often remains the only treatment option for patients with end-stage heart failure and is well established worldwide. Even though VAD coordinators play a key role in VAD programs, their responsibilities and daily duties are not clearly defined and characterized. Recently published data from the first 5-year multicenter clinical trial assessing experience with the HeartMate 3 left ventricular system (Abbott, Abbott Park, IL) show an overall survival of 61% at 5 years. When it comes to possible improvements to these systems, it is necessary for developers not only to know the status quo but also to determine and consider the visions and wishes of those individuals who take care of patients, provide education and deal with possible complications. This would be helpful a meaningful effort towards implementing a standard of care. METHODS: To fill this knowledge gap, we conducted an online survey using the SurveyMonkey tool, addressing representatives of programs implanting VADs worldwide. Representatives answered a standardized block of 14 questions and were asked to provide responses within 3 months. RESULTS: A total of 91 VAD coordinators from centers of various regions of the world completed the survey. The majority came from European countries. The numbers of patients followed up by the centers ranged from <20 to 390 patients. The majority of VAD coordinators had a nursing background (68%). Seventy-seven percent of the centers operate a 24-h hotline and 3-monthly visits to the outpatient department are most common. Fifty-nine percent of the centers do not use an infection scoring system for driveline wound care. The majority of the centers indicated that an optimized follow-up concept including wound care, medication, and social care is crucial and the key issue for an improved outcome. Smaller components and intensified psychosocial support ranked highest in questions about how to improve quality of life. Surprisingly, the future prospects of telemetric monitoring were not rated high in significance. CONCLUSIONS: There is a wide variability in the composition and tasks of VAD programs worldwide. Implementing a standard of care and improving psychosocial care as well as equipment is regarded most important to improve outcomes and quality of life. From the point of view of those responsible, the significance of telemetric monitoring seemed overrated.

Anisotropic topographies restore endothelial monolayer integrity and promote the proliferation of senescent endothelial cells.

Thrombogenicity remains a major issue in cardiovascular implants (CVIs). Complete surficial coverage of CVIs by a monolayer of endothelial cells (ECs) prior to implantation represents a promising strategy but is hampered by the overall logistical complexity and the high number of cells required. Consequently, extensive cell expansion is necessary, which may eventually lead to replicative senescence. Considering that micro-structured surfaces with anisotropic topography may promote endothelialization, we investigated the impact of gratings on the biomechanical properties and the replicative capacity of senescent ECs. After cultivation on gridded surfaces, the cells showed significant improvements in terms of adherens junction integrity, cell elongation, and orientation of the actin filaments, as well as enhanced yes-associated protein nuclear translocation and cell proliferation. Our data therefore suggest that micro-structured surfaces with anisotropic topographies may improve long-term endothelialization of CVIs.

Thrombus formation at the inflow cannula of continuous-flow left ventricular assist devices-A systematic analysis.

BACKGROUND: Despite numerous design iterations, thrombus formation at the inflow cannula of continuous-flow left ventricular assist devices remains an unsolved problem. We systematically investigated the impact of cannula surface on thrombus formation. METHODS: Thrombus appearance was photographically documented in 177 explanted hearts with the polished (N = 46) or sintered (N = 131) inflow cannula of the Medtronic HeartWare™ HVAD™ System. Thrombus load was compared for both inflow cannula types. Mean thrombus length was correlated with protruding cannula length. Support duration and the extent of thrombus growth were examined. The prevalence of thrombi at the left ventricular entry site and at the sintered-to-polished transition zone was correlated with left ventricular geometry and hemodynamic parameters. RESULTS: Polished inflow cannulas showed a greater percentage and also a greater mean length of thrombus formation at the entry site than sintered cannulas (91.3% [Pol] vs. 36.7% [sTi]; p < 0.0001; mean 7.6 mm vs. 1.9 mm; p < 0.0001). A comparison of the early postoperative period (POD1-90) with long-term support (POD>90) showed an increase in thrombus length originating from the transition zone (1.96 ± 3.41 mm vs. 3.03 ± 2.91 mm; p = 0.013). CONCLUSIONS: A sintered titanium surface at the entry site is crucial to enable anchoring of myocardial tissue to the cannula. As thrombus growth progresses on polished surfaces, a greater sintered length seems to be beneficial. After an initial three-month healing period, thrombus load appears to decline during prolonged support duration at the sintered entry site but not at the transition zone.

Interventional Procedures for Left Ventricular Assist Device-Associated Complications.

As patients on long-term left ventricular assist device (LVAD) face a substantial risk for open cardiac reoperation, interventional treatment approaches are becoming increasingly important in this population. We evaluated data of 871 patients who were on LVAD support between January 1, 2016 and December 1, 2020. Interventional treatments for LVAD-associated complications were performed in 76 patients. Seventeen patients underwent transcatheter aortic valve replacements (TAVR) and 61 patients underwent outflow graft interventions (OGI). TAVR improved symptoms in patients with severe symptomatic aortic regurgitation. Postinterventional complications included aggravation of preexisting right heart failure (RHF), third-degree atrioventricular block, and intrapump thrombosis (in 3 [16.7%], 2 [11.1%], and 1 [5.6%] patients, respectively). In outflow graft obstructions, OGI led to recovery of LVAD flow ( p < 0.001), unloading of the left ventricle ( p = 0.004), decrease of aortic valve opening time ( p = 0.010), and improvement of right heart function ( p < 0.001). Complications included bleeding, RHF, and others (in 9 [10.8%], 5 [6.0%], and 5 [6.0%] patients, respectively). Eight (9.6%) patients died within the hospital stay after OGI, including mortality secondary to prolonged cardiogenic shock. In conclusion, interventional procedures are a feasible and safe treatment modality for LVAD-associated complications.

Experience with a standardized protocol to predict successful explantation of left ventricular assist devices.

OBJECTIVE: Patients with a continuous-flow left ventricular assist device may show recovery of myocardial function with unloading. Identifying candidates for and predicting clinical and hemodynamic stability after left ventricular assist device explantation remain challenging. METHODS: Retrospective analysis of patients who underwent evaluation for left ventricular assist device explantation following a standardized protocol from January 2016 to March 2020. Patients who met screening criteria underwent echocardiography under "baseline," "minimal net flow," and "pump stop" conditions. If the protocol criteria were met, right heart catheterization with left ventricular assist device stoppage and occlusion of the outflow graft with a balloon catheter were performed. In patients with pulmonary capillary wedge pressure less than 16 mm Hg, explantation was performed under "pump stop" conditions. RESULTS: A total of 544 patients were screened. Of these, 57 (10.5%) underwent a total of 73 echocardiography under "baseline" "minimal net flow" and "pump stop" conditions and 46 underwent left ventricular assist device stoppage and occlusion of the outflow graft with balloon catheter maneuvers. Complications during the procedure were rare. Ultimately, 21 patients (3.9%) underwent explantation. The left ventricular ejection fraction at baseline was 55.5% ± 6.5%. The mean pulmonary capillary wedge pressure was 8.1 ± 2.6 mm Hg and increased to 10.7 ± 2.9 mm Hg under left ventricular assist device stoppage and occlusion of the outflow graft with a balloon catheter. A nonischemic cause of cardiomyopathy was more likely to be found in patients who underwent explantation (20/21 patients [95%], P = .020). The survival 1 year after explantation was 95.2%, with 1 death occurring 222 days after left ventricular assist device explantation. At follow-up (median 24.9 months [interquartile range, 16.4-43.1 months]), patients were in New York Heart Association class 1 (61.9%), 2 (28.6%), and 3 (9.5%). CONCLUSIONS: Our 4-year experience with a standardized protocol for left ventricular assist device explantation showed a low rate of adverse events. If all criteria are met, explantation can be performed safely and with an excellent survival and functional class.

Fluorescence In Situ Hybridization and Polymerase Chain Reaction to Detect Infections in Patients With Left Ventricular Assist Devices.

The development of driveline infections following left ventricular assist device (LVAD) implantation remains a major problem. We investigated the impact of fluorescence in situ hybridization (FISH) combined with 16S rRNA gene sequencing on the diagnosis of driveline infections. LVAD drivelines (n = 61) from 60 consecutive patients were obtained during LVAD explantation and subjected to FISH analysis. 16S rRNA gene polymerase chain reaction (PCR) and sequencing to identify the microorganisms were performed. Results were compared with those of a standard microbiological culture. The reasons for pump removal were heart transplantation (n = 22), weaning (n = 14), pump exchange due to pump thrombosis (n = 12), technical problems (n = 7), or death (n = 5). Of the 60 patients, 26 exhibited clinical signs of a VAD-specific infection, while 34 (with 35 drivelines) showed no clinical signs of infection before explantation. The spectrum of identified pathogens differed between FISH/PCR and conventional microbiological diagnostics. In general, the bacterial spectrum was more diverse in FISH/PCR as compared with conventional microbiology, which more often showed only typical skin flora (coagulase-negative staphylococci and Corynebacteriaceae). In addition to identifying the species, FISH/PCR provided information about the spatial distribution and invasiveness of the microorganisms. Cultures usually represent the only source of microbiological information for clinicians and often prove to be unsatisfactory in complex LVAD cases. FISH/PCR not only identified a greater number and variety of microorganisms than standard culture did, but it also provided information about the number, localization, and biofilm state of the pathogens, making it a useful tool for diagnosing the specific cause of LVAD driveline infections.

Diagnosis and Treatment Strategies of Outflow Graft Obstruction in the Fully Magnetically Levitated Continuous-Flow centrifugal Left Ventricular Assist Device: A Multicenter Case Series.

Outflow graft obstruction in left ventricular assist devices (LVADs) is a rare complication whose clinical presentation may be subtle. We present six cases of outflow graft obstruction in patients on HeartMate 3 LVAD detected between 648 and 1,222 days on support. Detection principles are described and treatment strategies discussed. Three patients were successfully managed with stents, one underwent surgical revision, one patient died despite emergency treatment, and the last patient without symptoms was listed for heart transplantation.

Longest Ongoing Support (13 Years) with Magnetically Levitated Left Ventricular Assist Device.

Implantation of a left ventricular assist device (LVAD) is an established treatment in end-stage heart failure. The longevity of LVAD support systems remains uncertain to a great extent because patients usually undergo transplantation, are weaned or die while on support before the maximum service life of these pumps is reached. We report about the hitherto longest published and still ongoing LVAD support of a 65 year old patient who received an Incor LVAD (Berlin Heart, Berlin, Germany, produced 2002-2018) 13 years ago. After pump exchange due to driveline damage, the patients were discharged home.

International Analysis of LVAD Point-of-Care Versus Plasma INR: A Multicenter Study.

International normalized ratio (INR) measurements manage risks of bleeding and clotting sequelae in the population with left ventricular assist device (LVAD). Studies suggest that point-of-care (POC) INR does not significantly differ from plasma INR (P-INR) values in other patient populations, although this has not been validated in a multicenter LVAD study. We sought to determine whether POC-INR and P-INR values differ significantly in the LVAD population and reviewed patients with permanent LVAD implantation at seven institutions internationally. Our cohort comprised of 279 paired POC-INR and P-INR checks in patients supported on average 630 ± 598 days postimplant with predominately HeartWare, HeartMate II, and HeartMate III devices. The population averaged 57.9 years of age, and there were 86.7% male. We found no statistically significant difference between POC-INR and P-INR values. International normalized ratio accuracy correlated weakly with the time between INR measurements (p < 0.001). When the time difference was less than 4 hours, the difference between INR pairs was significantly lower than measurements greater than 8 hours (p = 0.006). There was no statistically significant difference when comparing paired INR values and time after implant to INR check (p = 0.43), age (p = 0.12), known coagulopathy (p = 0.12), bleeding history (p = 0.22), or thrombosis history (p = 0.34). This is the first large multicenter international study comparing POC-INR and P-INR measurements in patients with LVAD and found no statistically significant difference between either methods, particularly when measured within less than 4 hours of each other.

Two implantable continuous-flow ventricular assist devices in a biventricular configuration: technique and results.

OBJECTIVES: No continuous-flow right ventricular assist device for long-term support is available at the moment. Two continuous-flow ventricular assist devices used in a continuous-flow biventricular assist device configuration is an emerging option which has proven its feasibility but still is not approved for routine use. We present our technique and results of modifying the left ventricular assist device and making it suitable for right ventricular support. METHODS: Between September 2009 and October 2017, 39 patients received implantation of a continuous-flow ventricular assist device for right ventricular support in a continuous-flow biventricular assist device configuration. For implantation of the HeartWare® manufacturers name of the pump HeartWare HVAD pump (HVAD)® centrifugal ventricular assist device, we performed 2 major modifications: banding of the outflow graft and reducing the intracaval length of the inflow cannula. The HVAD® could be safely implanted into the right atrium or ventricle. The HeartMate 3® left ventricular assist device needed no banding, but we increased the extraventricular part of the inflow cannula. RESULTS: The overall 30-day survival for the group receiving primarily a continuous-flow biventricular assist device was 72.7% (9.5% standard error of the mean (SEM)), and the 1-year survival was 45.0% (10.7% SEM). The overall 30-day survival for the group receiving a subsequent pump for right ventricular support in a continuous-flow biventricular assist device configuration after temporary right ventricular support was 71.4% (12.1% SEM), and 1-year survival was 40.8% (13.6% SEM). CONCLUSIONS: At the moment, there is a lack of a continuous-flow right ventricular assist device especially designed and approved for right ventricular support. Therefore, modifications in continuous-flow ventricular assist devices designed for the left ventricle are done to make them suitable for right ventricular support. However, more information is needed regarding the optimal surgical technique, patient selection and the optimal time point of implantation.

Left Ventricular Assist Devices: Challenges Toward Sustaining Long-Term Patient Care.

Over the last few decades, the left ventricular assist device (LVAD) technology has been tremendously improved transitioning from large and noisy paracorporeal volume displacement pumps to small implantable turbodynamic devices with only a single transcutaneous element, the driveline. Nevertheless, there remains a great demand for further improvements to meet the challenge of having a robust and safe device for long-term therapy. Here, we review the state of the art and highlight four key areas of needed improvement targeting long-term, sustainable LVAD function: (1) LVADs available today still have a high risk of thromboembolic and bleeding events that could be addressed by the rational fabrication of novel surface structures and endothelialization approaches aiming at improving the device hemocompatibility. (2) Novel, fluid dynamically optimized pump designs will further reduce blood damage. (3) Infection due to the paracorporeal driveline can be avoided with a transcutaneous energy transmission system that additionally allows for increased freedom of movement. (4) Finally, the lack of pump flow adaptation needs to be encountered with physiological control systems, working collaboratively with biocompatible sensor devices, targeting the adaptation of the LVAD flow to the perfusion requirements of the patient. The interdisciplinary Zurich Heart project investigates these technology gaps paving the way toward LVADs for long-term, sustainable therapy.

International coordinator survey results on the outpatient management of patients with the HeartWare® ventricular assist system.

PURPOSE: While the HeartWare® Ventricular Assist System (HVAS) is a successful therapy for end-stage heart failure, outpatient management methods can vary significantly and require further investigation. METHODS: A survey to assess the long-term HVAS patient management and monitoring strategies was completed by 36 international heart centers that currently have over 1,450 patients on VAD support either at home or in the hospital. Multiple choice questions examined VAD program characteristics, anticoagulation management, driveline exit-site dressing and showering recommendations, blood pressure and pump parameter monitoring, and patient discharge protocols. RESULTS: Outpatient international normalized ratio (INR) was most frequently measured every 3-4 days (28.6%), and the most frequent schedule for changing driveline exit site dressings was 3 times per week (30.6%). Only 25.7% of centers required their patients to measure blood pressure at home. A subgroup analysis was performed to assess the influence of center experience and larger centers generally had more frequent monitoring compared to smaller centers. CONCLUSIONS: This survey showed specific differences in outpatient management strategies that were previously unreported. However, further studies with correlations to patient outcomes are necessary to determine optimal patient management recommendations.

Emergency procedures for patients with a continuous flow left ventricular assist device.

The number of ventricular assist devices (VADs) being implanted for terminal heart failure is rising at an exponential rate. These implanted patients have a decreased mortality, but still have significant morbidities, as the prevalence of these patients increases in the community. When VAD patients are discharged to home, they will very likely require emergency medical services (EMSs) and emergency medical doctors (EDs) with their future care. The interface of these patients with the community would suggest an increasing prevalence of encounters requiring the need for acute medical care. This will place the initial responsibility of these patients in the hands of EMS first responders and emergency room providers. To date, there is very little literature published on out-of-hospital or ED care for VAD patients. Most EMS personnel and ED feel uncomfortable treating a patient with a VAD because they have not had sufficient exposure. The cardiovascular treatment of VAD patients in the field can pose different challenges typically encountered including difficulties measuring a pulse and sometimes undetectable BP. Despite these unique challenges, official guidelines or even standard operating procedures regarding the emergency treatment of VAD patients are still lacking. We present a basic overview of the most commonly used left VAD systems and propose guidelines that should be followed in the event of an emergency with a VAD patient out of hospital.