INTRODUCTION:Left ventricular assist devices (LVAD) have become an established therapy for end-stage heart failure over the last three decades. In currently available devices, the blood flow is estimated using a power consumption algorithm. In this study, intraoperative direct LVAD flow measurement with an ultrasonic flow probe was analyzed. METHODS:As part of our routine evaluation of optimal LVAD flow, intraoperative direct flow measurement at the outflow graft was performed using a 14-mm ultrasonic flow probe. Direct LVAD flow measurements were performed at different speed levels: 4400 rpm, 4800 rpm, 5200 rpm, and the optimal flow setting before chest closure. In twenty consecutive patients who underwent a durable LVAD implantation via median sternotomy in our institution between January and April 2025, direct flow measurement was compared with the estimated flow provided by the device. RESULTS:Median age was 63 [60;68] years, 17 (85%) were male, 8 (40%) had a history of acute myocardial infarction. Temporary mechanical circulatory support with a microaxial flow pump was necessary in 8 (40%) patients prior to durable LVAD implantation. Destination therapy was indicated in 12 (60%) cases. Mean flows at 4400 rpm were 2.9 ± 0.3 and 3.4 ± 0.4 L/min calculated by the pump and measured by the probe, respectively. Mean difference between the measurements was 0.56 L/min (95% CI [0.40, 0.70], p < 0.001). Mean flows at 4800 rpm were 3.5 ± 0.3 and 4.1 ± 0.5 L/min, respectively. Mean difference between the measurements was 0.55 L/min (95% CI [0.33, 0.77], p < 0.001). Mean flows at 5200 rpm were 4.2 ± 0.3 and 4.7 ± 0.5 L/min, respectively. Mean difference between the measurements was 0.53 L/min (95% CI [0.40, 0.70], p = 0.001). Mean optimal speed for patients was 5400 rpm, mean difference between the measurements was 0.49 L/min (95% CI [0.23, 0.74], p = 0.001). CONCLUSION:LVAD flow measured with an ultrasonic flow probe shows significantly higher results (approximately +0.5 L/min) compared to the flow estimated by the device. The difference remains constant at different LVAD speed modes. Intraoperative flow measurement employing an ultrasonic flow probe is a valuable tool for hemodynamic evaluation during implantation of a durable LVAD.

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. J Heart Lung Transplant 2024;43:251-260 (c) 2023 The Authors. Published by Elsevier Inc. on behalf of International Society for Heart and Lung Transplantation. This is an open access article under the CC BY license (http://creativecommons.org/ licenses/by/4.0/).

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.

Figure). All three of device models had significantly improved renal function at 1 month post-implantation compared to pre-implantation.EVA-HEAERT improved significantly up to 6 months, HeartMate II improved up to 3 months, and Jarvik only significantly improved up to 1 month after implantation.Conclusion: Renal function improved early after LVAD implantation, but gradually declined in most patients over 2 years.Changes in renal function after LVAD implantation were different in each device.

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.

Background: Approximately 15% of patients on left ventricular assist device (LVAD) support develop severe aortic regurgitation (AR). Since patients on LVAD support are considered at high risk for reoperation, the interventional approach is becoming increasingly important in this patient cohort.

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.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.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).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.

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.

Background: The HeartMate 3 (HM3) left ventricular assist device (LVAD) demonstrated excellent survival rates and was shown to be superior to other contemporary pumps. Nevertheless, optimal setting of LVAD support remains crucial to optimize patient outcomes, and the potential of the HM3 monitoring for noninvasive diagnostics of the hemodynamic condition (such as excessive unloading) has not yet been fully exhausted. Therefore, the aim of this study was to develop a noninvasive, continuous, high-resolution HM3 monitoring system (HM3 SNOOPY), and to assess its feasibility to detect undesired hemodynamic conditions in-vitro and in-vivo. Methods: Data packages routinely sent from the HM3 pump (1Hz sampling rate) to the external controller were captured using a noninvasive pickup coil mounted on the driveline. The induced voltage is processed using an analog amplifier stage and logical signal processing and transmitted via USB/UART interface to a laptop for live display and data storage using a graphical user interface (MATLAB). An in vitro mock loop simulating physiological flow conditions was used to compare mean estimated HM3 flow recorded by HM3 SNOOPY to measured flow (H11XL flowprobe, Transonic Systems) for different pump speeds (5000, 5500 and 6000 rpm). By mimicking suction events with a collapsible tube, an algorithm to detect excessive unloading was developed based on 10 statistical features quantifying the shape of estimated flow and impeller torque signals using 5-fold cross validation. To show the feasibility of the HM3 SNOOPY monitoring in-vivo, a prospective, single-center observational study (ClinicalTrials.gov NCT04641416) was introduced to apply the monitoring system to determine potentially undesired hemodynamic conditions and compare it to the PI event (standard monitoring). Results: In vitro analysis of 12,816 data points including 12.7% suction (n=1,440) revealed an absolute difference of estimated and measured flow of 0.43±0.57lpm (r=0.95). The 10 features calculated from HM3 SNOOPY were compared to discriminate between in-vitro normal operation and suction using a constant threshold level. The single best performing feature resulted in a correct classification rate of 86.7% (sensitivity of 84.4% and specificity of 87.0%), whereas the routinely available PI events monitoring detects the onset of suction events only. In vivo analysis of 10 HM3 patients implanted between August 2021 and February 2022 (Age: 60.1±9.2yrs, female: 10.0%, BMI: 27.1±3.2kg/m2), revealed 486.31 (10.4 to 1808.7) data points of potentially undesired pump flow conditions per hour, corresponding to a mean prevalence of 13.5% (0.3% to 50.2%) for HM3 SNOOPY and 0.3% (0.0% to 2.4%) for standard monitoring (PI events and low flows). Conclusion: This study indicates the feasibility of the novel HM3 SNOOPY for continuous, noninvasive HM3 monitoring both in vitro and in vivo. Further clinical validation of this system with echocardiographic data is currently ongoing.

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.

Purpose The Medtronic Corporation announced that the Heartware HVADTM will be removed from the global market for new implants as of June 3, 2021. Even after the official recall optimal care of the estimated 4000 patients worldwide is essential. In light of the past events where the new controller failed to start after a controller exchange, we must now focus on developing an optimal concept for this scenario. Methods Hence, we developed an algorithm to address the optimal patient management following a controller fault alarm in Heartware HVAD including two possible strategies for replacing the Medtronic HVAD with an Abbott HeartMate3 Results Between 06 and 10/2021 out of 215 ongoing HVAD patients 15 of them (5 female,10 male, median support time of 1815 (IQR:1156- 4007) days) contacted our VAD team regarding a controller fault alarm . In 10 patients the controller exchange following the algorithm was uneventful, in three cases minor bleeding events occurred. Two patients refused hospital admission and the exchange was performed at home with supervision via phone. Conclusion Even after the official recall of the Heartware HVAD, optimal care of the estimated 4000 patients with this system worldwide is essential. In light of the past events where the new controller failed to start after a controller exchange, we must now focus on developing an optimal concept for this scenario, as all patients will have to undergo a controller exchange in the next years once or even several times if support extends to another time period of more than approximately 4 years owing to the limited life of the internal battery of the HVAD controller. Even if preoperative echocardiography produces apparently stable findings, patients may experience rapid deterioration if the system fails, so that cardiovascular support must be established and a subsequent exchange of the HVAD to HM3 performed without delay. For patients with absolute contraindication of a pump stop like a thrombosed aortic valve permanently muting the controller fault alarm may be discussed. Continuous operation of the pump is not impaired; however the patient will have to be informed and has to acknowledge the constraints of the changed alarm display functionality and a shortened time of power-off alarm capacity.

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.

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.