Continuous LVAD monitoring reveals high suction rates in clinically stable outpatients

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.

Using pulsatility responses to breath-hold maneuvers to predict readmission rates in continuous-flow left ventricular assist device patients

BACKGROUND

Dynamic respiratory maneuvers induce heterogenous changes to flow-pulsatility in continuous-flow left ventricular assist device patients. We evaluated the association of these pulsatility responses with patient hemodynamics and outcomes.

METHODS

Responses obtained from HVAD (Medtronic) outpatients during successive weekly clinics were categorized into three ordinal groups according to the percentage reduction in flow-waveform pulsatility (peak-trough flow) upon inspiratory-breath-hold, (%∆P): (1) minimal change (%∆P ≤ 50), (2) reduced pulsatility (%∆P > 50 but <100), (3) flatline (%∆P = 100). Same-day echocardiography and right-heart-catheterization were performed. Readmissions were compared between patients with ≥1 flatline response (F-group) and those without (NF-group).

RESULTS

Overall, 712 responses were obtained from 55 patients (82% male, age 56.4 ± 11.5). When compared to minimal change, reduced pulsatility and flatline responses were associated with lower central venous pressure (14.2 vs. 11.4 vs. 9.0 mm Hg, p = 0.08) and pulmonary capillary wedge pressure (19.8 vs. 14.3 vs. 13.0 mm Hg, p = 0.03), lower rates of ≥moderate mitral regurgitation (48% vs. 13% vs. 10%, p = 0.01), lower rates of ≥moderate right ventricular impairment (62% vs. 25% vs. 27%, p = 0.03), and increased rates of aortic valve opening (32% vs. 50% vs. 75%, p = 0.03). The F-group (n = 28) experienced numerically lower all-cause readmissions (1.51 vs. 2.79 events-per-patient-year [EPPY], hazard-ratio [HR] = 0.67, p = 0.12), reduced heart failure readmissions (0.07 vs. 0.57 EPPY, HR = 0.15, p = 0.008), and superior readmission-free survival (HR = 0.47, log-rank p = 0.04). Syncopal readmissions occurred exclusively in the F-group (0.20 vs. 0 EPPY, p = 0.01).

CONCLUSION

Responses to inspiratory-breath-hold predicted hemodynamics and readmission risk. The impact of inspiratory-breath-hold on pulsatility can non-invasively guide hemodynamic management decisions, patient optimization, and readmission risk stratification.

Left Ventricular Assist Device Emergencies: Diagnosis and Management

Durable left ventricular assist devices (LVADs) are a virtually limitless advanced therapy option for an increasingly growing population of patients with end-stage advanced heart failure. As of 2019, 30% to 40% of all patients diagnosed with heart failure were categorized as New York Heart Association class III or IV. In 2018 more than 3.2 million office visits and 1.4 million emergency department visits carried a primary diagnosis of heart failure. Given the rapid growth of the LVAD population, facility in the diagnosis and management of common perioperative and outpatient LVAD emergencies has become of paramount importance in a variety of clinical settings.

Monitoring left ventricular assist device parameters to detect flow- and power-impacting complications: a proof of concept

Aims

The number of patients on left ventricular assist device (LVAD) support increases due to the growing number of patients with end-stage heart failure and the limited number of donor hearts. Despite improving survival rates, patients frequently suffer from adverse events such as cardiac arrhythmia and major bleeding. Telemonitoring is a potentially powerful tool to early detect deteriorations and may further improve outcome after LVAD implantation. Hence, we developed a personalized algorithm to remotely monitor HeartMate3 (HM3) pump parameters aiming to early detect unscheduled admissions due to cardiac arrhythmia or major bleeding.

Methods and results

The source code of the algorithm is published in an open repository. The algorithm was optimized and tested retrospectively using HeartMate 3 (HM3) power and flow data of 120 patients, including 29 admissions due to cardiac arrhythmia and 14 admissions due to major bleeding. Using a true alarm window of 14 days prior to the admission date, the algorithm detected 59 and 79% of unscheduled admissions due to cardiac arrhythmia and major bleeding, respectively, with a false alarm rate of 2%.

Conclusion

The proposed algorithm showed that the personalized algorithm is a viable approach to early identify cardiac arrhythmia and major bleeding by monitoring HM3 pump parameters. External validation is needed and integration with other clinical parameters could potentially improve the predictive value. In addition, the algorithm can be further enhanced using continuous data.

Care and Monitoring of Pregnant Patients With Left Ventricular Assist Devices

Cardiovascular disease is one of the leading causes of maternal mortality in the United States. Although still rare, pregnancy in patients with left ventricular assist devices (LVADs) is becoming more common. Typical indications for the use of LVADs in reproductive-aged females include ischemic cardiomyopathy, nonischemic (familial) dilated cardiomyopathy, peripartum cardiomyopathy, and some forms of myocarditis. An LVAD drains blood through a cannula placed into the apex of the left ventricle and then returns it to the proximal aorta bypassing the aortic valve allowing hemodynamic support in parallel with the native circulation. The physiologic changes associated with pregnancy, mainly increased blood volume and hypercoagulability, may adversely affect patients with LVADs, leading to many experts recommending against pregnancy. Maternal-fetal medicine specialists should have a central role within a multidisciplinary team required to provide optimal care for this high-risk group of patients.

An in vitro model to study suction events by a ventricular assist device: validation with clinical data

Introduction: Ventricular assist devices (LVADs) are a valuable therapy for end-stage heart failure patients. However, some adverse events still persist, such as suction that can trigger thrombus formation and cardiac rhythm disorders. The aim of this study is to validate a suction module (SM) as a test bench for LVAD suction detection and speed control algorithms. Methods: The SM consists of a latex tube, mimicking the ventricular apex, connected to a LVAD. The SM was implemented into a hybrid in vitro-in silico cardiovascular simulator. Suction was induced simulating hypovolemia in a profile of a dilated cardiomyopathy and of a restrictive cardiomyopathy for pump speeds ranging between 2,500 and 3,200 rpm. Clinical data collected in 38 LVAD patients were used for the validation. Clinical and simulated LVAD flow waveforms were visually compared. For a more quantitative validation, a binary classifier was used to classify simulated suction and non-suction beats. The obtained classification was then compared to that generated by the simulator to evaluate the specificity and sensitivity of the simulator. Finally, a statistical analysis was run on specific suction features (e.g., minimum impeller speed pulsatility, minimum slope of the estimated flow, and timing of the maximum slope of the estimated flow). Results: The simulator could reproduce most of the pump waveforms observed in vivo. The simulator showed a sensitivity and specificity and of 90.0% and 97.5%, respectively. Simulated suction features were in the interquartile range of clinical ones. Conclusions: The SM can be used to investigate suction in different pathophysiological conditions and to support the development of LVAD physiological controllers.

Long-term assist device patients admitted to ICU: Tips and pitfalls

Left ventricular assist device (LVAD) therapy is well-established in the treatment of end-stage cardiac failure. Indications are bridge to transplant (BTT), bridge to candidacy (BTC), bridge to recovery (BTR), and destination therapy (DT). The durability and adverse event (AE) rate of LVADs have improved over the years. However, due to donor shortage, the duration of support in the BTT population has increased tremendously; similarly, DT patients are on the device for a long time. Consequently, the number of readmissions of long-term LVAD patients has increased. In cases of severe AEs, intensive care unit (ICU) treatment can be necessary. Infectious complications are the most common AE. Furthermore, embolic or hemorrhagic strokes can occur due to foreign surfaces, acquired von Willebrand syndrome, and anticoagulation treatment. Another consequence of the coagulative status, in combination with the continuous flow, are gastrointestinal bleeding events. Moreover, in most patients, an isolated LVAD is implanted, and this involves the risk of late right heart failure. Adjustment of pump speed and optimization of the volume status can help solve this issue. Malignant arrhythmias, pre-existing or de novo after LVAD implantation, can be a life-threatening AE. Antiarrhythmic medical therapy or ablation are potential treatment options. As for specific LVADs, the Medtronic HeartWare™ ventricular assist device (HVAD) is not manufactured and distributed currently; however, 4000 patients are still on the device. Pump thrombosis can occur, wherein thrombolytic therapy is the first-line treatment option. Additionally, the HVAD can fail to restart after controller exchange due to technical issues, and precautions must be taken. The Momentum 3 trial showed superior survival without pump exchange or disabling stroke in patients treated with the HeartMate 3^Ⓡ (HM3; Abbott, Abbott Park, IL, USA) device in comparison to the HeartMate II (HMII). However, in a few cases, a twisted graft or bio debris formation between the outflow graft and bend relief could be observed, causing outflow graft obstruction. Patients on LVADs are still heart failure patients, in many cases with comorbidities. Therefore, many situations can occur requiring ICU treatment. Ethical aspects should always be the focus when taking care of these patients.

Impact of preoperative mitral regurgitation on left ventricular assist device patients: propensity score-matched analysis of the EUROMACS dataset

OBJECTIVES

Mitral regurgitation (MR) is frequently observed in patients undergoing left ventricular assist device implantation. We investigated the impact of preoperative MR on left ventricular assist device patients.

METHODS

A retrospective propensity score-matched analysis of adult patients enrolled in the EUROMACS registry between 1 January 2011 and 30 November 2021 was performed. Patients were divided into 2 groups according to the grade of preoperative MR: none-to-mild (MR 0-II) or moderate-to-severe (MR III-IV).

RESULTS

Following 1:1 propensity score matching, each group consisted of 914 patients. Incidence of postoperative temporary right ventricular support, reoperation for bleeding and dialysis was similar. MR III-IV demonstrated shorter median intensive care unit stay [14 days (6; 27.8) vs 10 days (5; 22), P = 0.004] and ventilation time [72 h (22, 320) vs 31 h (18, 150), P < 0.001]. Mortality was lower for MR III-IV patients [subdistribution hazard ratio: 0.66, 95% confidence interval (CI): 0.59-0.73, P < 0.001]. The 1-year survival was 68.1% (95% CI: 65.1-71.3%) in MR 0-II and 75% (95% CI: 72.1-78%) in MR III-IV. A lower incidence of total complications [odds ratio (OR): 0.93 (0.89-0.98), P = 0.003] and trend towards a lower risk of neurological dysfunction (subdistribution hazard ratio: 0.79; 95% CI: 0.61-1.01, P = 0.063) and sustained ventricular tachycardia [OR: 0.93 (0.54-1.03), P = 0.074] were demonstrated for MR III-IV. The risk of fatal stroke and pump thrombosis was similar.

CONCLUSIONS

Moderate-to-severe MR in patients undergoing left ventricular assist device implantation is associated with better mid-term survival and lower incidence of total major adverse events and complications. The incidence of severe postoperative complications including fatal stroke and device thrombosis was similar.

Potential of Medical Management to Mitigate Suction Events in Ventricular Assist Device Patients

Ventricular suction is a common adverse event in ventricular assist device (VAD) patients and can be due to multiple underlying causes. The aim of this study is to analyze the potential of different therapeutic interventions to mitigate suction events induced by different pathophysiological conditions. To do so, a suction module was embedded in a cardiovascular hybrid (hydraulic-computational) simulator reproducing the entire cardiovascular system. An HVAD system (Medtronic) was connected between a compliant ventricular apex and a simulated aorta. Starting from a patient profile with severe dilated cardiomyopathy, four different pathophysiological conditions leading to suction were simulated: hypovolemia (blood volume: -900 ml), right ventricular failure (contractility -70%), hypotension (systemic vascular resistance: 8.3 Wood Units), and tachycardia (heart rate:185 bpm). Different therapeutic interventions such as volume infusion, ventricular contractility increase, vasoconstriction, heart rate increase, and pump speed reduction were simulated. Their effects were compared in terms of general hemodynamics and suction mitigation. Each intervention elicited a different effect on the hemodynamics for every pathophysiological condition. Pump speed reduction mitigated suction but did not ameliorate the hemodynamics. Administering volume and inducing a systemic vasoconstriction were the most efficient interventions in both improving the hemodynamics and mitigating suction. When simulating volume infusion, the cardiac powers increased, respectively, by 38%, 25%, 42%, and 43% in the case of hypovolemia, right ventricular failure, hypotension, and tachycardia. Finally, a management algorithm is proposed to identify a therapeutic intervention suited for the underlying physiologic condition causing suction.

A Sensorless Modular Multiobjective Control Algorithm for Left Ventricular Assist Devices: A Clinical Pilot Study

Background

Contemporary Left Ventricular Assist Devices (LVADs) mainly operate at a constant speed, only insufficiently adapting to changes in patient demand. Automatic physiological speed control promises tighter integration of the LVAD into patient physiology, increasing the level of support during activity and decreasing support when it is excessive.

Methods

A sensorless modular control algorithm was developed for a centrifugal LVAD (HVAD, Medtronic plc, MN, USA). It consists of a heart rate-, a pulsatility-, a suction reaction—and a supervisor module. These modules were embedded into a safe testing environment and investigated in a single-center, blinded, crossover, clinical pilot trial (clinicaltrials.gov, NCT04786236). Patients completed a protocol consisting of orthostatic changes, Valsalva maneuver and submaximal bicycle ergometry in constant speed and physiological control mode in randomized sequence. Endpoints for the study were reduction of suction burden, adequate pump speed and flowrate adaptations of the control algorithm for each protocol item and no necessity for intervention via the hardware safety systems.

Results

A total of six patients (median age 53.5, 100% male) completed 13 tests in the intermediate care unit or in an outpatient setting, without necessity for intervention during control mode operation. Physiological control reduced speed and flowrate during patient rest, in sitting by a median of −75 [Interquartile Range (IQR): −137, 65] rpm and in supine position by −130 [−150, 30] rpm, thereby reducing suction burden in scenarios prone to overpumping in most tests [0 [−10, 2] Suction events/minute] in orthostatic upwards transitions and by −2 [−6, 0] Suction events/min in Valsalva maneuver. During submaximal ergometry speed was increased by 86 [31, 193] rpm compared to constant speed for a median flow increase of 0.2 [0.1, 0.8] L/min. In 3 tests speed could not be increased above constant set speed due to recurring suction and in 3 tests speed could be increased by up to 500 rpm with a pump flowrate increase of up to 0.9 L/min.

Conclusion

In this pilot study, safety, short-term efficacy, and physiological responsiveness of a sensorless automated speed control system for a centrifugal LVAD was established. Long term studies are needed to show improved clinical outcomes.

Clinical Trial Registration

ClinicalTrials.gov, identifier: NCT04786236.

Validation of Intrinsic Left Ventricular Assist Device Data Tracking Algorithm for Early Recognition of Centrifugal Flow Pump Thrombosis

Advanced stage heart failure patients can benefit from the unloading effects of an implantable left ventricular assist device. Despite best clinical practice, LVADs are associated with adverse events, such as pump thrombosis (PT). An adaptive algorithm alerting when an individual’s appropriate levels in pump power uptake are exceeded, such as in the case of PT, can improve therapy of patients implanted with a centrifugal LVAD. We retrospectively studied 75 patients implanted with a centrifugal LVAD in a single center. A previously optimized adaptive pump power-tracking algorithm was compared to clinical best practice and clinically available constant threshold algorithms. Algorithm performances were analyzed in a PT group (n = 16 patients with 30 PT events) and a thoroughly selected control group (n = 59 patients, 34.7 patient years of LVAD data). Comparison of the adaptive power-tracking algorithm with the best performing constant threshold algorithm resulted in sensitivity of 83.3% vs. 86.7% and specificity of 98.9% vs. 95.3%, respectively. The power-tracking algorithm produced one false positive detection every 11.6 patient years and early warnings with a median of 3.6 days prior to PT diagnosis. In conclusion, a retrospective single-center validation study with real-world patient data demonstrated advantageous application of a power-tracking algorithm into LVAD systems and clinical practice.

Comparison of device-based therapy options for heart failure with preserved ejection fraction: a simulation study

Successful therapy of heart failure with preserved ejection fraction (HFpEF) remains a major unmet clinical need. Device-based treatment approaches include the interatrial shunt device (IASD), conventional assist devices pumping blood from the left ventricle (LV-VAD) or the left atrium (LA-VAD) towards the aorta, and a valveless pulsatile assist device with a single cannula operating in co-pulsation with the native heart (CoPulse). Hemodynamics of two HFpEF subgroups during rest and exercise condition were translated into a lumped parameter model of the cardiovascular system. The numerical model was applied to assess the hemodynamic effect of each of the four device-based therapies. All four therapy options show a reduction in left atrial pressure during rest and exercise and in both subgroups (> 20%). IASDs concomitantly reduce cardiac output (CO) and shift the hemodynamic overload towards the pulmonary circulation. All three mechanical assist devices increase CO while reducing sympathetic activity. LV-VADs reduce end-systolic volume, indicating a high risk for suction events. The heterogeneity of the HFpEF population requires an individualized therapy approach based on the underlying hemodynamics. Whereas phenotypes with preserved CO may benefit most from an IASD device, HFpEF patients with reduced CO may be candidates for mechanical assist devices.

Does Size Matter for Female Continuous-flow LVAD Recipients? A Translational Approach to a Decade Long Question

Females have increased risk of right-ventricular failure (RVF) and 3 month mortality after left-ventricular assist device (LVAD) implantation. In this translational study, we tested the hypothesis that sex differences in outcomes are driven by pump-induced LV size-volume mismatch, due to a negative impact on interventricular septal (IVS) interdependence. Adult continuous-flow LVAD recipients from the International Society For Heart And Lung Transplantation Mechanically Assisted Circulatory Support registry (n = 15,498) were studied to determine association of female sex with outcomes of 3 month mortality and RVF. Female sex was associated with smaller preimplant left-ventricular end-diastolic diameter (6.5 vs. 6.9 cm, p < 0.001), increased 3 month mortality (odds ratio [OR]: 1.42, p < 0.001) and RVF (OR: 1.18, p = 0.005). Smaller left-ventricular end-diastolic diameter was associated with worse outcomes after LVAD implantation (OR for mortality: 1.20, p < 0.001; RVF: 1.09, p < 0.001), and attenuated the association of female sex with these outcomes. In test bench heart phantoms (n = 4), the IVSs of smaller hearts demonstrated abnormal leftward shift earlier than larger hearts (volume change at IVS shift: 40 [95% confidence interval: 30-52] vs. 50 [95% confidence interval: 48-69] ml). Smaller LV size partially mediates worse post-LVAD outcomes for female patients, due to lower volume thresholds for adverse IVS shifting.

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.

A Flow Sensor-Based Suction-Index Control Strategy for Rotary Left Ventricular Assist Devices

Rotary left ventricular assist devices (LVAD) have emerged as a long-term treatment option for patients with advanced heart failure. LVADs need to maintain sufficient physiological perfusion while avoiding left ventricular myocardial damage due to suction at the LVAD inlet. To achieve these objectives, a control algorithm that utilizes a calculated suction index from measured pump flow (SIMPF) is proposed. This algorithm maintained a reference, user-defined SIMPF value, and was evaluated using an in silico model of the human circulatory system coupled to an axial or mixed flow LVAD with 5–10% uniformly distributed measurement noise added to flow sensors. Efficacy of the SIMPF algorithm was compared to a constant pump speed control strategy currently used clinically, and control algorithms proposed in the literature including differential pump speed control, left ventricular end-diastolic pressure control, mean aortic pressure control, and differential pressure control during (1) rest and exercise states; (2) rapid, eight-fold augmentation of pulmonary vascular resistance for (1); and (3) rapid change in physiologic states between rest and exercise. Maintaining SIMPF simultaneously provided sufficient physiological perfusion and avoided ventricular suction. Performance of the SIMPF algorithm was superior to the compared control strategies for both types of LVAD, demonstrating pump independence of the SIMPF algorithm.

Pump position and thrombosis in ventricular assist devices: Correlation of radiographs and CT data

Malpositioning of left ventricular assist devices (LVAD) is a risk factor for thrombosis, but its identification from clinical imaging remains challenging. X-rays and CT scans were analyzed and parameters identified that correlated to pump thrombosis. Retrospective imaging data of patients (n = 115) with HeartmateII (HMII) or HVAD were analyzed in two groups (pump-thrombosis PT, n = 15 vs matched control group NT, n = 15) using routine X-rays and CT scans. In CT, directional deviations of the inflow cannula in three-chamber and two-chamber view (α and β angles) were identified. In HVAD PT frontal radiographs showed reduced pump body area and smaller minor axis (PT 41.3 ± 4.8 mm vs NT 34.9 ± 6.0 mm, p = 0.026), and in the lateral radiographs the visibility of the inflow cannula served as a predictive parameter for PT. In HMII patients, no parameters were associated with PT. The angle α differed significantly (NT −1.2 ± 7.5°, PT −22.0 ± 4.7°, p = 0.006) in HVAD patients. Further, correlations of x-ray parameters with CT angles α and β showed that radiographs can be used to identify malpositioned pumps. Well-aligned inflow cannula positions are essential. HVAD patients with a posterior rotation of the inflow cannula have a higher risk of pump thrombosis. This risk can reliably be identified from routine radiographs.

The left ventricular assist device as a patient monitoring system

Technological progress of left ventricular assist devices (LVADs) towards rotary blood pumps and the optimization of medical management contributed to the significant improvements in patient survival as well as LVAD support duration. Even though LVAD therapy is now well-established for end-stage heart failure patients, the long-term occurrence of adverse events (AE) such as bleeding, infection or stroke, still represent a relevant burden. An early detection of AE, before onset of major symptoms, can lead to further optimization of patient treatment and thus mitigate the burden of AE. Continuous patient monitoring facilitates identification of pathophysiological states and allows anticipation of AE to improve patient management. In this paper, methods, algorithms and possibilities for continuous patient monitoring based on LVAD data are reviewed. While experience with continuous LVAD monitoring is currently limited to a few centers worldwide, the pace of developments in this field is fast and we expect these technologies to have a global impact on the well-being of LVAD patients.

Removal of a Knotted Pulmonary Artery Catheter Using a Percutaneous Tracheostomy Set

Placement of a pulmonary artery catheter is not a risk-free technique. Related incidents include ventricular arrhythmias, air embolisms, pulmonary artery perforation, infections, or catheter thrombosis. Herein the authors report a rare complication-the intracardiac knotting and its successful extraction using a percutaneous tracheostomy set in a hemodynamically compromised patient after a heart transplant.

Out of hospital management of LVAD patients during COVID-19 outbreak

Coronavirus disease 2019 (COVID‐19) is a pandemic touching thousands of people all around the world. Patients supported with left ventricular assist devices (LVADs) are affected by long‐standing cardiovascular diseases and subjected to variations of the normal cardiovascular physiology, thus requiring an even closer monitoring during the COVID‐19 outbreak. Nevertheless, the COVID‐19 pandemic led to a drastic reduction in routine clinical activities and a consequent risk of looser connections between LVAD patients and their referring center. Potential deleterious effects of such a situation can be a delayed recognition of LVAD‐related complications, misdiagnosis of COVID‐19, and impaired social and psychological well‐being for patients and families. As one of the largest LVAD programs worldwide, we designed a sustainable and enforceable telemonitoring algorithm which can be easily adapted to every LVAD center so as to maintain optimal quality of care for LVAD patients during the COVID‐19 pandemic.

Optimal cannula positioning of HeartMate 3 left ventricular assist device

Cannula position in HeartMate II and HeartWare left ventricular assist devices (LVADs) is associated with clinical outcome. This study aimed to investigate the clinical implication of the device positioning in HeartMate 3 LVAD cohort. Consecutive patients who underwent HeartMate 3 LVAD implantation were followed for one year from index discharge. At index discharge, chest X-ray parameters were measured: (a) cannula coronal angle, (b) height of pump bottom, (c) cannula sagittal angle, and (d) cannula lumen area. The association of each measurement of cannula position with one-year clinical outcomes was investigated. Sixty-four HeartMate 3 LVAD patients (58 years old, 64% male) were enrolled. In the multivariable Cox regression model, the cannula coronal angle was a significant predictor of death or heart failure readmission (hazard ratio 1.27 [1.01-1.60], P = .045). Patients with a cannula coronal angle ≤28° had lower central venous pressure (P = .030), lower pulmonary capillary wedge pressure (P = .027), and smaller left ventricular size (P = .019) compared to those with the angle >28°. Right ventricular size and parameters of right ventricular function were also better in the narrow angle group, as was one-year cumulative incidence of death or heart failure readmission (10% vs. 50%, P = .008). Narrow cannula coronal angle in patients with HeartMate 3 LVADs was associated with improved cardiac unloading and lower incidence of death or heart failure readmission. Larger studies to confirm the implication of optimal device positioning are warranted.

Continuous LVAD monitoring reveals high suction rates in clinically stable outpatients

Suction of the left ventricle can lead to potentially life‐threatening events in left ventricular assist device (LVAD) patients. With the resolution of currently available clinical LVAD monitoring healthcare professionals are unable to evaluate patients’ suction occurrences in detail. This study investigates occurrences and durations of suction events and their associations with tachycardia in stable outpatients. Continuous high‐resolution LVAD data from HVAD patients were analyzed in the early outpatient period for 15 days. A validated suction detection from LVAD signals was used. Suction events were evaluated as suction rates, bursts of consecutive suction beats, and clusters of suction beats. The occurrence of tachycardia was analyzed before, during, and after suction clusters. Furthermore, blood work, implant strategy, LVAD speed setting, inflow cannula position, left ventricular diameters, and adverse events were evaluated in these patients. LVAD data of 10 patients was analyzed starting at 78 ± 22 postoperative days. Individuals’ highest suction rates per hour resulted in a median of 11% (range 3%‐61%). Bursts categorized as consecutive suction beats with n = 2, n = 3‐5, n = 6‐15, and n > 15 beats were homogenously distributed with 10.3 ± 0.8% among all suction beats. Larger suction bursts were followed by shorter suction‐free periods. Tachycardia during suction occurred in 12% of all suction clusters. Significant differences in clinical parameters between individuals with high and low suction rates were only observed in left ventricular end‐diastolic and end‐systolic diameters (P < .02). Continuous high‐resolution LVAD monitoring sheds light on outpatient suction occurrences. Interindividual and intraindividual characteristics of longitudinal suction rates were observed. Longer suction clusters have higher probabilities of tachycardia within the cluster and more severe types of suction waveforms. This work shows the necessity of improved LVAD monitoring and the implementation of an LVAD speed control to reduce suction rates and their concomitant burden on the cardiovascular system.