Population pharmacokinetics of cyclosporine A in pediatric patients with thalassemia undergoing allogeneic hematopoietic stem cell transplantation.

PURPOSE: To establish the population pharmacokinetics (PPK) model of cyclosporine A(CsA) in pediatric patients with thalassemia undergoing allogeneic hematopoietic stem cell transplantation (HSCT), aiming at providing a reference for clinical dose individualization of CsA. METHODS: Children with thalassemia who underwent allogeneic HSCT were enrolled retrospectively. The PPK structural model and the random variable model of CsA were established on NONMEN. And goodness of fit plots (GOFs), visual predictive check (VPC), and bootstrap and normalized prediction distribution errors (NPDE) were used to evaluate the final model. RESULTS: A one-compartment model with first-order absorption was employed to fit the base model. A total of 74 pediatric patients and 600 observations of whole blood concentration were included. The final model included weight (WT) in clearance (CL), alongside post-operative day (POD), fluconazole (FLUC), voriconazole (VORI), posaconazole (POSA), and red blood cell count (RBC) significantly. All the model evaluations were passed. CONCLUSION: In the PPK model based on the pediatric cohort on CsA with thalassemia undergoing allogeneic HSCT, WT, POD, FLUC, VORI, POSA, and RBC were found to be the significant factors influencing CL of CsA. The reliability and robustness of the final model were excellent. It is expected that the PPK model can assist in individualizing dosing strategy clinically.

Thermally Healable Electrolyte-Electrode Interface for Sustainable Quasi-Solid Zinc-ion Batteries.

Quasi-solid zinc-ion batteries using hydrogel electrolytes show great potential in energy storage devices owing to their intrinsic safety, fewer side reactions and wide electrochemical windows. However, the dendrite issues on the zinc anodes cannot be fundamentally eliminated and the intrinsic anode-electrolyte interfacial interspace is rarely investigated. Here, we design a dynamically healable gelatin-based hydrogel electrolyte with a highly reversible sol-gel transition, which can construct a conformal electrode-electrolyte interface and further evolve into a stable solid-solid interface by in situ solidification. The unique helical gelatin chain structure provides a uniform channel for zinc ion transport by the bridging effect of sulfate groups. As a consequence, the dynamically healable interface enables dendrite-free zinc anodes and repeatedly repairs the anode-electrolyte interfacial interspaces by the reversible sol-gel transition of gelatin electrolyte to retain long-lasting protection for sustainable zinc-ion batteries.

Perovskite-based photodetector for real-time and quantitative monitoring of sports motion.

Reliable monitoring the movement amplitude and dynamics during sports exercise is significant for improving training results and preventing training wound. Here, we present a printed perovskite-based photodetector for real-time and quantitative monitoring of sports motion. The ordered nucleation and growth of perovskite crystals are regulated by the 4-acetamidothiophenol (AMTP) at the interface, which promotes the size of perovskite crystals into the micrometer. Benefiting from the uniformity of the AMTP-regulated MAPbI3, the as-prepared photodetector gives great photocurrent response under indoor light or outdoor light. During the exercise, real-time monitoring sports motion is achieved through detecting the illumination changing of photodetectors attaching on the wrist and ankles. Moreover, twelve kinds of common sports can be quantitatively analyzed with the detection of illumination changing on the photodetector. Such photodetector provides an efficient measurement method of wearable electronics for sports monitoring.

Bulk-Phase Reconstruction Enables Robust Zinc Metal Anodes for Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries are inherently safe, but the severe dendrite growth and corrosion reaction on zinc anodes greatly hinder their practical applications. Most of the strategies for zinc anode modification refer to the research of lithium metal anodes on surface regulation without considering the intrinsic mechanisms of zinc anode. Herein, we first point out that surface modification cannot permanently protect zinc anodes due to the unavoidable surface damage during the stripping process by solid-liquid conversion. A bulk-phase reconstruction strategy is proposed to introduce abundant zincophilic sites both on the surface and inside the commercial zinc foils. The bulk-phase reconstructed zinc foil anodes exhibit uniform surfaces with high zincophilicity even after deep stripping, significantly improving the resistance to dendrite growth and side reactions. Our proposed strategy suggests a promising direction for the development of dendrite-free metal anodes for practical rechargeable batteries with high sustainability.

Molecular Recognition-Modulated Hetero-Assembly of Nanostructures for Visualizable and Portable Detection of Circulating miRNAs.

Biomolecular markers, particularly circulating microRNAs (miRNAs) play an important role in diagnosis, monitoring, and therapeutic intervention of cancers. However, existing detection strategies remain intricate, laborious, and far from being developed for point-of-care testing. Here, we report a portable colorimetric sensor that utilizes the hetero-assembly of nanostructures driven by base pairing and recognition for direct detection of miRNAs. Following hybridization, two sizes of nanoparticles modified with single-strand DNA can be robustly assembled into heterostructures with strong optical resonance, exhibiting distinct structure colors. Particularly, the large nanoparticles are first arranged into nanochains to enhance scattering signals of small nanoparticles, which allows for sensitive detection and quantification of miRNAs without the requirement of target extraction, amplification, and fluorescent labels. Furthermore, we demonstrate the high specificity and single-base selectivity of testing different miRNA samples, which shows great potential in the diagnosis, staging, and monitoring of cancers. These heterogeneous assembled nanostructures provide an opportunity to develop simple, fast, and convenient tools for miRNAs detection, which is suitable for many scenarios, especially in low-resource setting.

Change in Caregiver Health-Related Quality of Life From Before to Early After Surgery: SUSTAIN-IT Study.

BACKGROUND: Information about health-related quality of life (HRQOL) among caregivers of older patients with heart failure who receive heart transplantation (HT) and mechanical circulatory support (MCS) is sparse. We describe differences and factors associated with change in HRQOL before and early post-surgery among caregivers of older heart failure patients who underwent 3 surgical therapies: HT with pretransplant MCS (HT MCS), HT without pretransplant MCS (HT non-MCS), and long-term MCS. METHODS: Caregivers of older patients (60-80 years) from 13 US sites completed the EQ-5D-3 L visual analog scale (0 [worst]-100 [best] imaginable health state) and dimensions before and 3 and 6 months post-surgery. Analyses included linear regression, t tests, and nonparametric tests. RESULTS: Among 227 caregivers (HT MCS=54, HT non-MCS=76, long-term MCS=97; median age 62.7 years, 30% male, 84% White, 83% spouse/partner), EQ-5D visual analog scale scores were high before (84.8±14.1) and at 3 (84.7±13.0) and 6 (83.9±14.7) months post-surgery, without significant differences among groups or changes over time. Patient pulmonary hypertension presurgery (ß=-13.72 [95% CI, -21.07 to -6.36]; P<0.001) and arrhythmia from 3 to 6 months post-operatively (ß=-14.22 [95% CI, -27.41 to -1.02]; P=0.035) were associated with the largest decrements in caregiver HRQOL; patient marital/partner status (ß=6.21 [95% CI, 1.34-11.08]; P=0.013) and presurgery coronary disease (ß=8.98 [95% CI, 4.07-13.89]; P<0.001) were associated with the largest improvements. CONCLUSIONS: Caregivers of older patients undergoing heart failure surgeries reported overall high HRQOL before and early post-surgery. Understanding factors associated with caregiver HRQOL may inform decision-making and support needs. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02568930.

High-entropy solvent design enabling a universal electrolyte with a low freezing point for low-temperature aqueous batteries.

Amide additives acting as hydrogen-bonding ligands effectively break the cross-linking structures between water molecules and increase the entropy of mixed solvents, thus enabling a mixed solvent with an ultralow freezing point of -98 °C. Zinc-ion batteries using this hybrid solvent exhibit good cycling stability over a wide temperature range from -60 °C to 50 °C.

Association Between Caregiver Burden and Patient Recovery After Left Ventricular Assist Device Implantation: Insights From Sustaining Quality of Life of the Aged: Heart Transplant or Mechanical Support.

INTRODUCTION: After left ventricular assist device (LVAD) implantation, caregivers may experience increasing burden because of new roles and responsibilities. We examined the association between caregiver burden at baseline and patient recovery after long-term LVAD implantation in patients ineligible for heart transplantation. METHODS: Between October 1, 2015, and December 31, 2018, data from 60 patients with a long-term LVAD (age, 60-80 years) and caregivers through 1 postoperative year were analyzed. Caregiver burden was measured using the Oberst Caregiving Burden Scale, a validated instrument used for measuring caregiver burden. Patient recovery post-LVAD implantation was defined by change in Kansas City Cardiomyopathy Questionnaire-12 (KCCQ-12) overall summary score and rehospitalizations over 1 year. Multivariable regression models (least-squares for change in KCCQ-12 and Fine-Gray cumulative incidence for rehospitalizations) were used to assess for association with caregiver burden. RESULTS: Patients were 69.4 ± 5.5 years old, 85% men, and 90% White. Over the first year post-LVAD implantation, there was a 32% cumulative probability of rehospitalization; 72% (43/60) of patients had an improvement of ≥5 points in KCCQ-12 scores. Caregivers were 61.2 ± 11.5 years old, 93% women, 81% White, and 85% married. Median Oberst Caregiving Burden Scale Difficulty and Time scores at baseline were 1.13 and 2.27, respectively. Higher caregiver burden was not significantly associated with hospitalizations or change in patient health-related quality of life during the first year post-LVAD implantation. CONCLUSIONS: Higher caregiver burden at baseline was not associated with patient recovery in the first year after LVAD implantation. Understanding the associations between caregiver burden and patient outcomes after LVAD implantation is important as excessive caregiver burden is a relative contraindication for LVAD implantation.

Caregiver burden before heart transplantation and long-term mechanical circulatory support: Findings from the sustaining quality of life of the aged: Transplant or mechanical support (SUSTAIN-IT) study.

BACKGROUND: Caregiving for heart failure (HF) patients is burdensome. We examined differences in caregiver burden for 3 groups of older advanced HF patients: (1) supported with mechanical circulatory support (MCS) before heart transplantation (HT MCS), (2) awaiting transplant without MCS (HT non-MCS), and (3) prior to long-term MCS and factors associated with burden. METHOD: From October 1, 2015 to December 31, 2018, we enrolled 276 caregivers for HF patients from 13 U.S. sites: 85 HT MCS, 96 HT non-MCS, and 95 prior to long-term MCS. At enrollment, caregivers completed the Oberst Caregiving Burden Scale (15 items, 2 subscales: time (range = 1-5; higher score = more time spent on task) and difficulty (range = 1-5; higher score = higher difficulty of task) and other measures. Statistical analyses included descriptive statistics, ANOVA, chi-square tests, and linear regression. RESULT: Overall, caregivers were aged 60.8 ± 9.8 years and predominantly white, female, spouses, well educated, and reported ≥1 comorbidities. Caregivers overall reported a moderate amount of time spent on tasks and slight task difficulty. Caregivers for HT non-MCS candidates reported significantly less perceived time spent on tasks than caregivers for HT MCS candidates and caregivers for patients prior to long-term MCS (2.2 ± 0.74 vs 2.4 ± 0.74 vs 2.5 ± 0.71, respectively, p = 0.02) and less perceived difficulty of tasks (1.2 ± 0.33 vs 1.4 ± 0.53 vs 1.4 ± 0.54, respectively, p = 0.01). Caregiver and patient factors were associated with caregiver burden. CONCLUSIONS: Prior to HT and long-term MCS, caregiver burden was low to moderate. Caregiver factors were predominantly associated with caregiver burden. Understanding caregiver burden and factors affecting caregiver burden may enhance preoperative advanced therapies discussions and guide caregiver support.

At-Home COVID-19 Rapid Antigen Test Down to 0.03 pg mL-1 of Nucleocapsid Protein.

Rapid and ultra-sensitive detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical for early screening and management of COVID-19. Currently, the real-time reverse transcription polymerase chain reaction (rRT-PCR) is the primary laboratory method for diagnosing SARS-CoV-2. It is not suitable for at-home COVID-19 diagnostic test due to the long operating time, specific equipment, and professional procedures. Here an all-printed photonic crystal (PC) microarray with portable device for at-home COVID-19 rapid antigen test is reported. The fluorescence-enhanced effect of PC amplifies the fluorescence intensity of the labeled probe, achieving detection of nucleocapsid (N-) protein down to 0.03 pg mL-1 . A portable fluorescence intensity measurement instrument gives the result (negative or positive) by the color of the indicator within 5 s after inserting the reacted PC microarray test card. The N protein in inactivated virus samples (with cycle threshold values of 26.6-40.0) can be detected. The PC microarray provides a general and easy-to-use method for the timely monitoring and eventual control of the global coronavirus pandemic.

Wearable perovskite solar cells by aligned liquid crystal elastomers.

In a flexible perovskite solar cell, the bottom interface between perovskite and the electron-transporting layer is critical in determining its efficiency and reliability. High defect concentrations and crystalline film fracturing at the bottom interface substantially reduce the efficiency and operational stability. In this work, a liquid crystal elastomer interlayer is intercalated into a flexible device with the charge transfer channel toughened by the aligned mesogenic assembly. The molecular ordering is instantly locked upon photopolymerization of liquid crystalline diacrylate monomers and dithiol-terminated oligomers. The optimized charge collection and the minimized charge recombination at the interface boost the efficiency up to 23.26% and 22.10% for rigid and flexible devices, respectively. The liquid crystal elastomer-induced suppression of phase segregation endows the unencapsulated device maintaining >80% of the initial efficiency for 1570 h. Moreover, the aligned elastomer interlayer preserves the configuration integrity with remarkable repeatability and mechanical robustness, which enables the flexible device to retain 86% of its original efficiency after 5000 bending cycles. The flexible solar cell chips are further integrated into a wearable haptic device with microneedle-based arrays of sensors to demonstrate a pain sensation system in virtual reality.

Rapid Identification and Monitoring of Multiple Bacterial Infections Using Printed Nanoarrays.

Fast and accurate detection of microbial cells in clinical samples is highly valuable but remains a challenge. Here, a simple, culture-free diagnostic system is developed for direct detection of pathogenic bacteria in water, urine, and serum samples using an optical colorimetric biosensor. It consists of printed nanoarrays chemically conjugated with specific antibodies that exhibits distinct color changes after capturing target pathogens. By utilizing the internal capillarity inside an evaporating droplet, target preconcentration is achieved within a few minutes to enable rapid identification and more efficient detection of bacterial pathogens. More importantly, the scattering signals of bacteria are significantly amplified by the nanoarrays due to strong near-field localization, which supports a visualizable analysis of the growth, reproduction, and cell activity of bacteria at the single-cell level. Finally, in addition to high selectivity, this nanoarray-based biosensor is also capable of accurate quantification and continuous monitoring of bacterial load on food over a broad linear range, with a detection limit of 10 CFU mL-1 . This work provides an accessible and user-friendly tool for point-of-care testing of pathogens in many clinical and environmental applications, and possibly enables a breakthrough in early prevention and treatment.

A Semi-solid Zinc Powder-based Slurry Anode for Advanced Aqueous Zinc-ion Batteries.

The booming of aqueous zinc-ion batteries (AZIBs) draws the researchers' attention to issues of zinc metal anodes, such as uncontrollable dendrite growth, corrosion, and volume effects. Zinc powder anode is more suitable for the industrial application of AZIBs than the widely used zinc foil anode due to its low cost, tunability and processability. However, the related solutions are rarely studied because the above issues of zinc metal anode are more serious in zinc powder anode. Herein, for the first time, we design a semi-solid zinc slurry anode consisting of zinc powder and zincophilic tin additive dispersed in a conductive elastic rheological network. Zinc can be deposited homogeneously on the dispersed tin particles, which avoids agglomerative zinc deposition and alleviates volume change during repeated zinc stripping/plating. Moreover, the practical application of the full cell with slurry is very promising since its operating life can be easily extended by facile slurry renewal.

Isotropic Amorphous Protective Layer with Uniform Interfacial Zincophobicity for Stable Zinc Anode.

Aqueous zinc-ion batteries (AZIBs) have drawn the attention of numerous researchers owing to their high safety and cost-effectiveness. However, the dendrite growth and side reactions of the zinc (Zn) anodes limit their further practical applications. Herein, a porous amorphous silicon nitride protective layer with high zincophobicity is constructed on the Zn anode surface, which can guide the uniform stripping/plating of Zn2+ underneath the protective layer through its isotropic Zn affinity to alleviate the growth of dendrites and by-products. As a result, the amorphous silicon nitride-protected Zn anode can maintain a stable Coulombic efficiency (CE) of 98.8% and low voltage hysteresis for 710 cycles in the half cell. The full cell with the as-prepared Zn anode can deliver excellent electrochemical performances (89.0% capacity retention and 144.4 mAh g-1 discharge capacity after 1000 cycles at 4 A g-1 ). This work reveals the key role of uniform metal affinity induced by the amorphous materials in the interface modification of metal anodes, which is instructive for the design of stable metal anodes.

Population pharmacokinetics of mycophenolate mofetil in pediatric patients early after liver transplantation.

Objective: To investigate the factors influencing the pharmacokinetics of mycophenolate mofetil (MMF) in pediatric patients after liver transplantation, and to establish a population pharmacokinetics model, which can provide a reference for clinical dosage adjustment. Methods: A prospective study in a single center was performed on pediatric patients who were administrated with mycophenolate mofetil dispersible tablets (MMFdt) for at least 4 days after liver transplantation continuously. Blood samples were collected in ethylene diamine tetraacetic acid anticoagulant tubes before dosing and 0.5, 1, 2, 4, 8, and 12 h after the morning intake of MMFdt. The concentrations of mycophenolic acid (MPA) in plasma were assayed with a validated reverse-phase high-performance liquid chromatography method. UGT1A8 518C > G, UGT1A9 -275T > A, UGT1A9 -2152C > T, UGT2B7 211G > T, SLC O 1B1 521T > C polymorphism were determined by Sanger sequencing. Nonlinear mixed effects modeling was used to establish the population pharmacokinetics (PPK) model. The predictability and stability of the model were internally evaluated by the goodness of fit plots, visual prediction check, normalized prediction errors, and bootstraps. Results: A two-compartment model with first-order absorption and first-order elimination was established with 115 MPA concentrations from 20 pediatric patients. The final model were: CL/F (L/h) = 14.8×(WT/7.5)0.75×(DOSE/11.16)0.452×е0.06, Ka (h-1) = 2.02×(WT/7.5)-0.25, Vc/F (L) = 6.01×(WT/7.5), Vp/F (L) = 269 (fixed), Q/F (L/h) = 15.4×(WT/7.5)0.75×е1.39. Where CL/F was the apparent clearance rate, Ka was the absorption rate constant, Vc/F was the apparent distribution volume of the central compartment, Vp/F was the apparent distribution volume of the peripheral compartment, Q/F was the atrioventricular clearance rate, WT was the body weight of the subject, and DOSE was the MMFdt administered dose. The model indicated there was large inter-individual variability in CL/F and Q/F after multiple dosing of MMFdt. Internal evaluation results showed that the final model had good stability and prediction performance. Conclusion: A stable and predictive population pharmacokinetic model of MMFdt in pediatric patients after the early stage of liver transplantation was established. The pediatric patient's weight and the dose of MMFdt can be a reference to adjust the MMFdt dose.

Lateral Heterostructured Vis-NIR Photodetectors with Multimodal Detection for Rapid and Precise Classification of Glioma.

Precise diagnosis of the boundary and grade of tumors is especially important for surgical dissection. Recently, visible and near-infrared (Vis-NIR) absorption differences of tumors are demonstrated for a precise tumor diagnosis. Here, a template-assisted sequential printing strategy is investigated to construct lateral heterostructured Vis-NIR photodetectors, relying on the up-conversion nanoparticles (UCNPs)/perovskite arrays. Under the sequential printing process, the synergistic effect and co-confinement are demonstrated to induce the UCNPs to cover both sides of the perovskite microwire. The side-wrapped lateral heterogeneous UCNPs/perovskite structure exhibits more satisfactory responsiveness to Vis-NIR light than the common fully wrapped structure, due to sufficient visible-light-harvesting ability. The Vis-NIR photodetectors with R reaching 150 mA W-1 at 980 nm and 1084 A W-1 at 450 nm are employed for the rapid classification of glioma. The detection accuracy rate of 99.3% is achieved through a multimodal analysis covering the Vis-NIR light, which provides a reliable basis for glioma grade diagnosis. This work provides a concrete example for the application of photodetectors in tumor detection and surgical diagnosis.

Printing nanoparticle-based isotropic/anisotropic networks for directional electrical circuits.

With the demand for integrated nanodevices, anisotropic conductive films are one type of interconnection structure for electronic components, which have been widely used for improving the integration of the system in printed circuit boards. This work presents a template-assisted printing strategy for the fabrication of nanoparticle-based networks with multi electrical properties. By manipulating the microfluid behavior under the guidance of the grid-shaped template, the continuity of liquid bridges can be precisely controlled in two directions. The isotropous circuits with crossbar paths, discrete paths as well as unidirectional paths are obtained, which achieve the switching of on/off states in the circuits. This work demonstrates a new type of directional circuits by the template-assisted printing method, which provides an effective fabrication strategy for electrical components and integrated systems.

Designing Zinc Deposition Substrate with Fully Preferred Orientation to Elude the Interfacial Inhomogeneous Dendrite Growth.

The development of zinc-ion batteries with high energy density remains a great challenge due to the uncontrollable dendrite growth on their zinc metal anodes. Film anodes plated on the substrate have attracted increasing attention to alleviate these dendrite issues. Herein, we first point out that both the random crystal orientation and the low metal affinity of the substrate are important factors of zinc dendrite formation. Accordingly, the (1 0 1) fully preferred tin interface layer with high zinc affinity was fabricated by chemical tin plating on (1 0 0) oriented copper. This tin decorated copper substrate can realize high reversible zinc plating/stripping behavior, and full cell using this zinc plated substrate can be operated for more than 1000 cycles with high capacity retention (85.3%) and low electrochemical impedance. The proposed strategy can be also applied to lithium metal batteries, which demonstrates that the substrate orientation regulation and metal affinity design are the promising approaches to achieve dendrite-free metal anode and overcome the challenges of highly reactive metal anodes.

Hyponatremia Is a Powerful Predictor of Poor Prognosis in Left Ventricular Assist Device Patients.

Serum sodium is an established prognostic marker in heart failure (HF) patients and is associated with an increased risk of morbidity and mortality. We sought to study the prognostic value of serum sodium in left ventricular assist device (LVAD) patients and whether hyponatremia reflects worsening HF or an alternative mechanism. We identified HF patients that underwent LVAD implantation between 2008 and 2019. Hyponatremia was defined as Na ≤134 mEq/L at 3 months after implantation. We assessed for differences in hyponatremia before and after LVAD implantation. We also evaluated the association of hyponatremia with all-cause mortality and recurrent HF hospitalizations. There were 342 eligible LVAD patients with a sodium value at 3 months. Among them, there was a significant improvement in serum sodium after LVAD implantation compared to preoperatively (137.2 vs. 134.7 mEq/L, P < 0.0001). Patients with and without hyponatremia had no significant differences in echocardiographic and hemodynamic measurements. In a multivariate analysis, hyponatremia was associated with a markedly increased risk of all-cause mortality (HR 3.69, 95% CI, 1.93-7.05, P < 0.001) when accounting for age, gender, co-morbidities, use of loop diuretics, and B-type natriuretic peptide levels. Hyponatremia was also significantly associated with recurrent HF hospitalizations (HR 2.11, 95% CI, 1.02-4.37, P = 0.04). Hyponatremia in LVAD patients is associated with significantly higher risk of all-cause mortality and recurrent HF hospitalizations. Hyponatremia may be a marker of ongoing neurohormonal activation that is more sensitive than other lab values, echocardiography parameters, and hemodynamic measurements.

Time Spent Engaging in Health Care Among Patients With Left Ventricular Assist Devices.

OBJECTIVES: This study aims to examine a novel patient-centered metric of time spent engaging in left ventricular assist device (LVAD)-related clinical care outside the home. BACKGROUND: Although LVAD implantation can improve survival and functional capacity in patients with advanced heart failure, this may occur at the expense of significant time spent engaging in LVAD-related health care activities. METHODS: The authors retrospectively assessed consecutive patients at a single center who received a continuous-flow LVAD between May 9, 2008, and December 31, 2019, and queried health care encounters after implantation, including all inpatient encounters and LVAD-related ambulatory encounters. Patient-level time metrics were determined, including the total number of days with any health care encounter, and the total estimated time spent receiving care. The primary outcome was the proportion (%) of days alive with an LVAD spent engaged in at least 1 health care encounter. The secondary outcome was the proportion (%) of total time alive with an LVAD spent receiving care. RESULTS: Among 373 patients, the median number of days alive with LVAD was 390 (IQR: 158-840 days). Patients had a median number of 88 (IQR: 45-161) days with ≥1 health care encounter, accounting for 23.2% (IQR: 16.3%-32.4%) of their days alive with an LVAD. A median 6.0% (IQR: 2.1%-14.1%) and 15.0% (IQR: 10.7%-20.0%) of total days alive were spent in inpatient and ambulatory encounters, respectively. Patients spent a median of 592 (IQR: 197-1,257) hours receiving care, accounting for 5.6% (IQR: 2.2%-12.7%) of their total time alive with an LVAD. CONCLUSIONS: LVAD patients spent more than 1 of every 5 days engaging in health care. Our findings may inform strategies to improve efficiency of postdischarge care delivery and expectations for post-treatment care.