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Aims The aims of the Critical Care Cardiology Trials Network (CCCTN) are to develop a registry to investigate the epidemiology of cardiac critical illness and to establish a multicentre research network to conduct randomised clinical trials (RCTs) in patients with cardiac critical illness. Methods and results The CCCTN was founded in 2017 with 16 centres and has grown to a research network of over 40 academic and clinical centres in the United States and Canada. Each centre enters data for consecutive cardiac intensive care unit (CICU) admissions for at least 2 months of each calendar year. More than 20 000 unique CICU admissions are now included in the CCCTN Registry. To date, scientific observations from the CCCTN Registry include description of variations in care, the epidemiology and outcomes of all CICU patients, as well as subsets of patients with specific disease states, such as shock, heart failure, renal dysfunction, and respiratory failure. The CCCTN has also characterised utilization patterns, including use of mechanical circulatory support in response to changes in the heart transplantation allocation system, and the use and impact of multidisciplinary shock teams. Over years of multicentre collaboration, the CCCTN has established a robust research network to facilitate multicentre registry-based randomised trials in patients with cardiac critical illness. Conclusion The CCCTN is a large, prospective registry dedicated to describing processes-of-care and expanding clinical knowledge in cardiac critical illness. The CCCTN will serve as an investigational platform from which to conduct randomised controlled trials in this important patient population.

Background: In Europe, there is greater acceptance of hearts from higher-risk donors for transplantation, whereas in North America, the donor heart discard rate is significantly higher. A Donor Utilization Score (DUS) was used to compare European and North American donor characteristics for recipients included in the International Society for Heart and Lung Transplantation registry from 2000 to 2018. DUS was further evaluated as an independent predictor for 1-year freedom from graft failure, after adjusting for recipient risk. Lastly, we assessed donor-recipient risk matching with the outcome of 1-year graft failure. Methods: DUS was applied to the International Society for Heart and Lung Transplantation cohort using meta-modeling. Posttransplant freedom from graft failure was summarized by Kaplan-Meier survival. Multivariable Cox proportional hazard regression was applied to quantify the effects of DUS and Index for Mortality Prediction After Cardiac Transplantation score on the 1-year risk of graft failure. We present 4 donor/recipient risk groups using the Kaplan-Meier method. Results: European centers accept significantly higher-risk donor hearts compared to North America. DUS 0.45 versus 0.54, P P P P Conclusions: European heart transplantation centers are more likely to accept higher-risk donor hearts than North American centers. Acceptance of borderline-quality donor hearts for lower-risk recipients could improve donor heart utilization without compromising recipient survival.

BACKGROUND The Society of Thoracic Surgeons (STS) Intermacs Registry represents a real-world data source of durable, left ventricular assist devices that can address knowledge gaps not informed through randomized clinical trials. We sought to compare survival with contemporary left ventricular assist device technologies using multiple analytic approaches to assess concordance of treatment effects and to validate prior STS Intermacs observations. METHODS Patients (≥19 years of age) enrolled into STS Intermacs between August 2017 and June 2019 were stratified by device type (continuous flow, centrifugal left ventricular assist device with hybrid levitation [CF-HL] or full magnetic levitation [CF-FML]). The primary outcome was 1-year survival assessed by 3 statistical methodologies (multivariable regression, propensity score matching, and instrumental variable analysis). RESULTS Of 4448 patients, 2012 (45.2%) received the CF-HL and 2436 (54.8%) received the CF-FML. One-year survival for the CF-FML was 88% vs 79% for the CF-HL (overall P < .001), with a hazard ratio for mortality of 3.18 for the CF-HL (P < .0001) after risk adjustment. With propensity score matching (n = 1400 each cohort), 1-year survival was 87% for the CF-FML vs 80% for the CF-HL, with a hazard ratio of 3.20 for mortality with the CF-HL (P < .0001) after risk adjustment. With an instrumental variable analysis, the probability of receiving the CF-HL was associated with a hazard ratio of 3.11 (P < .0001). CONCLUSIONS Statistical methodology using propensity score matching and instrumental variable analysis increased the robustness of observations derived from real-world data and demonstrates the feasibility of performing comparative effectiveness research using STS Intermacs. These analyses provide additional evidence supporting a survival benefit of the CF-FML vs CF-HL.

BACKGROUND: A better understanding is needed of the burdens and benefits of left ventricular assist device (LVAD) implantation on patients’ physical, mental, and social well-being. The purpose of this report was to evaluate the validity of Patient-Reported Outcomes Measurement Information System (PROMIS) measures for LVAD patients and to estimate clinically important score differences likely to have implications for patient treatment or care. METHODS: Adults from 12 sites across all US geographic regions completed PROMIS measures ≥3 months post-LVAD implantation. Other patient-reported outcomes (eg, Kansas City Cardiomyopathy Questionnaire-12 item), clinician ratings, performance tests, and clinical adverse events were used as validity indicators. Criterion and construct validity and clinically important differences were estimated with Pearson correlations, ANOVA methods, and Cohen d effect sizes. RESULTS: Participants’ (n=648) mean age was 58 years, and the majority were men (78%), non-Hispanic White people (68%), with dilated cardiomyopathy (55%), long-term implantation strategy (57%), and New York Heart Association classes I and II (54%). Most correlations between validity indicators and PROMIS measures were medium to large (≥0.3; p CONCLUSIONS: The findings provide convincing evidence for the relevance and validity of PROMIS physical, mental, and social health measures in patients from early-to-late post-LVAD implantation. Findings may inform shared decision-making when patients consider treatment options. Patients with an LVAD, their caregivers, and their clinicians should find it useful to interpret the meaning of their PROMIS scores in relation to the general population, that is, PROMIS may help to monitor a return to normalcy in everyday life. REGISTRATION: URL: https://clinicaltrials.gov ; Unique: identifier: NCT03044535.

Background: Algorithmic application of the 2019 Society of Cardiovascular Angiography and Intervention (SCAI) shock stages effectively stratifies mortality risk for patients with cardiogenic shock. However, clinician assessment of SCAI staging may differ. Moreover, the implications of the 2022 SCAI criteria update remain incompletely defined. Methods: The Critical Care Cardiology Trials Network is a multicenter registry of cardiac intensive care units (CICUs). Between 2019 and 2021, participating centers (n=32) contributed at least a 2-month snapshot of consecutive medical CICU admissions. In-hospital mortality was assessed across 3 separate staging methods: clinician assessment, Critical Care Cardiology Trials Network algorithmic application of the 2019 SCAI criteria, and a revision of the Critical Care Cardiology Trials Network application using the 2022 SCAI criteria. Results: Of 9612 admissions, 1340 (13.9%) presented with cardiogenic shock with in-hospital mortality of 35.2%. Both clinician and algorithm-based staging using the 2019 SCAI criteria identified a stepwise gradient of mortality risk (stage C–E: 19.0% to 83.7% and 14.6% to 52.2%, respectively; P trend P trend Conclusions: Both clinician and algorithm-based application of the 2019 SCAI stages identify a stepwise gradient of mortality risk, although clinician-staging may better allocate higher risk patients into advanced SCAI stages. Updated algorithmic staging using the 2022 SCAI criteria and vasoactive-inotropic score further refines risk stratification.

BACKGROUND Hospitalizations account for almost one-third of $4.1 trillion healthcare cost in the US. A substantial portion of these hospitalizations are readmissions, which led to Hospital Readmissions Reduction Program (HRRP) in 2012.15 HRRP reduces payments to hospitals with excess readmissions. In 2018, more than $700 million was withheld; this is expected to exceed $1 billion by the year 2022.1 More importantly, there is nothing more physically and emotionally taxing for readmitted patients, demoralizing hospital physicians, nurses, and administrators. OBJECTIVE Given this high uncertainty of home recovery, intelligent monitoring is needed to predict the outcome of discharged patients to reduce readmissions. Therefore, we developed a remote, low-cost, cloud-based machine learning (ML) platform to enable precision health monitoring, which may fundamentally alter the delivery of home healthcare. METHODS Our platform consists of wearable, iPhone-synced sensors connected to our cloud-based ML interface to analyze physical activity remotely and predict clinical outcomes. This system was deployed in skilled nursing facilities where we collected over 17,000 person-day data over 2 years, generating a solid training database. We employed these data to train our XGBoost-based ML environment to conduct a clinical trial, “Activity Assessment of Patients Discharged from Hospital (ACT-I Trial, Stanford University Institutional Review Board Approval #53805),” to test the hypothesis that a comprehensive profile of physical activity will predict clinical outcome. RESULTS We achieved precise prediction of the patients’ clinical outcomes with a sensitivity of 87%, specificity of 79%, and accuracy of 85%. CONCLUSIONS We present AiCare’s comprehensive technology solution, consisting of wearable sensors, Bluetooth low energy (BLE)-enabled iOS infrastructure, ML algorithm to implement artificial intelligence, and API-enabled web technology, to measure the daily activities of patients. In this study, remote data collection, robust XGBoost AI analysis and reliable prediction of clinical outcome are reported.

The authors sought to examine the long-term cognitive outcome of patients with continuous flow left ventricular assist device (CF-LVAD).Data on long-term neurocognitive outcome in LVAD are limited. We examined the neurocognitive outcome of patients who received a CF-LVAD as destination therapy.Patients with HeartWare (HVAD) and HeartMate II who were enrolled in the ENDURANCE and ENDURANCE Supplemental trials were eligible. Cognition was evaluated with neuropsychological testing preoperatively and at 6, 12, and 24 months after implantation. General linear models identified demographic, disease, and treatment factors that predicted decline on each neurocognitive measure.Of 668 patients who completed baseline testing and at least 1 follow-up evaluation, 552 were impaired at baseline on at least 1 cognitive measure. At each follow-up, approximately 23% of tested patients declined and 20% improved relative to baseline on at least 1 cognitive measure. Of those who were intact at baseline, only 10%-12% declined in delayed memory and 11%-16% declined in executive function at all 3 follow-ups. For patients impaired at baseline, delayed memory decline was associated with the HVAD device and male sex, whereas executive function decline was associated with the HVAD device and stroke during CF-LVAD support. For patients intact at baseline, male sex and history of hypertension were associated with decline in immediate memory and executive function, respectively.Neurocognitive function remained stable or improved for most patients (∼80%) with CF-LVAD at 6, 12, and 24 months after implantation. Male sex, hypertension, HVAD, and stroke were associated with cognitive decline.

Introduction Traditionally, implantation of Left Ventricular Assist Devices (LVADs) is performed via median sternotomy . Recently, less invasive thoracotomy approaches are growing in popularity as they involve less surgical trauma, potentially less bleeding, and may preserve right ventricular function . We hypothesized implantation of LVADs via thoracotomy has less perioperative right ventricular failure (RVF) and shorter postoperative length of stay (LOS). Methods Continuous flow LVAD implants from Intermacs between February 6, 2014 - December 31, 2018 were identified. Patients implanted via thoracotomy were propensity matched in a 1:1 ratio with patients implanted via sternotomy. Outcomes were compared between sternotomy and thoracotomy approach and by device type (axial, centrifugal-flow with hybrid levitation (CF-HL), centrifugal-flow with full magnetic levitation devices (CF-FML)). The primary outcome was time to first moderate or severe RVF. Secondary outcomes included survival and LOS. Results Overall 978 thoracotomy patients were matched with 978 sternotomy patients. Over the study period, 242 thoracotomy patients and 219 sternotomy patients developed RVF with no significant difference in time to first moderate to severe RVF by surgical approach overall ( p = 0.27) or within CF-HL (p = 0.36) or CF-FML devices (p = 0.25). Survival did not differ by implant technique (150 deaths in thoracotomy group, 154 deaths in sternotomy group; p = 0.58). However, sternotomy approach was associated with a significantly shorter LOS (17 Vs 18 days, p = 0.009). Conclusion As compared to sternotomy, implantation of continuous flow LVADs via thoracotomy approach does not reduce moderate to severe RVF or improve survival but does reduce post-operative LOS. Device type did not influence outcomes and most centers did a small volume of thoracotomy implants.

BACKGROUND Multicenter data on long term survival following LVAD implantation that make use of contemporary definitions of RV failure are limited. Furthermore, traditional survival analyses censor patients who receive a bridge to heart transplant. Here we compare the outcomes of LVAD patients who develop post-operative RV failure accounting for the transitional probability of receiving an interim heart transplantation. METHODS We use a retrospective cohort of LVAD patients sourced from multiple high-volume centers based in the United States. Five- and ten-year survival accounting for transition probabilities of receiving a heart transplant were calculated using a multi-state Aalen Johansen survival model. RESULTS Of the 897 patients included in the study, 238 (26.5%) developed post-operative RV failure at index hospitalization. At 10 years the probability of death with post-op RV failure was 79.28% vs 61.70% in patients without (HR 2.10; 95% CI 1.72 - 2.57; p = < .001). Though not significant, patients with RV failure were less likely to be bridged to a heart transplant (HR 0.87, p = .4). Once transplanted the risk of death between both patient groups remained equivalent; the probability of death after a heart transplant was 3.97% in those with post-operative RV failure shortly after index LVAD implant, as compared to 14.71% in those without. CONCLUSIONS AND RELEVANCE Long-term durable mechanical circulatory support is associated with significantly higher mortality in patients who develop post-operative RV failure. Improving outcomes may necessitate expeditious bridge to heart transplant wherever appropriate, along with critical reassessment of organ allocation policies.

Donor-derived cell free DNA (dd-cfDNA) and gene expression profiling (GEP) offer noninvasive alternatives to rejection surveillance after heart transplantation; however, there is little evidence on the paired use of GEP and dd-cfDNA for rejection surveillance.A single center, retrospective analysis of adult heart transplant recipients. A GEP cohort, transplanted from January 1, 2015 through December 31, 2017 and eligible for rejection surveillance with GEP was compared to a paired testing cohort, transplanted July 1, 2018 through June 30, 2020, with surveillance from both dd-cfDNA and GEP. The primary outcomes were survival and rejection-free survival at 1 year post-transplant.In total 159 patients were included, 95 in the GEP and 64 in the paired testing group. There were no differences in baseline characteristics, except for less use of induction in the paired testing group (65.6%) compared to the GEP group (98.9%), P .01. At 1-year, there were no differences between the paired testing and GEP groups in survival (98.4% vs. 94.7%, P = .23) or rejection-free survival (81.3% vs. 73.7% P = .28).Compared to post-transplant rejection surveillance with GEP alone, pairing dd-cfDNA and GEP testing was associated with similar survival and rejection-free survival at 1 year while requiring significantly fewer biopsies.

Background: Ventricular assist device (VAD) patients are at high risk for morbidities and mortality. One potentially beneficial component of the Joint Commission VAD Certification process is the requirement that individual VAD programs select 4 performance measures to improve and optimize patients’ clinical outcomes. Problem Statement: Review of patient data after our program’s first certification visit in 2008 showed that, compared to national recommendations and published reports, our patients had suboptimal outcomes in 4 areas after device implantation: length of hospital stay, receipt of early (Methods: Plan-Do-Study-Act processes were implemented to shorten length of stay, increase patient receipt of early physical therapy, decrease driveline infection incidence, and improve nutritional status. With 2008 as our baseline, we deployed interventions for each outcome area across 2009 to 2017. Performance improvement activities included staff, patient, and family didactic, one-on-one, and hands-on education; procedural changes; and outcomes monitoring with feedback to staff on progress. Descriptive and inferential statistics were examined to document change in the outcomes. Outcomes: Across the performance improvement period, length of stay decreased from 40 to 23 days; physical therapy consults increased from 87% to 100% of patients; 1-year driveline infection incidence went from 38% to 23.5%; and the percentage of patients with prealbumin within the normal range increased from 84% to 90%. Implications: Performance improvement interventions may enhance ventricular assist device patient outcomes. Interventions’ sustainability should be evaluated to ensure that gains are not lost over time.

Purpose of review Simultaneous heart-liver (SHL) transplants are only a small proportion of overall heart and liver transplantation, they have been increasing in frequency and thus challenge the equitable allocation of organs. Recent findings The incidence of SHL transplants is reviewed along with the outcomes of SHL transplants and their impact on the waitlist, particularly in the context of solitary heart and liver transplantation. The ethical implications, most importantly the principles of utility and equity, of SHL transplant are addressed. In the context of utility, the distinction of a transplant being life-saving versus life-enhancing is investigated. The risk of hepatic decompensation for those awaiting both solitary and combined organ transplantation is an important consideration for the principle of equity. Lastly, the lack of standardization of programmatic approaches to SHL transplant candidates, the national approach to allocation, and the criteria by which programs are evaluated are reviewed. Summary As with all multiorgan transplantation, SHL transplantation raises ethical issues of utility and equity. Given the unique patient population, good outcomes, lack of alternatives, and overall small numbers, we feel there is continued ethical justification for SHL, but a more standardized nationwide approach to the evaluation, listing, and allocation of organs is warranted.

To understand the challenges for thoracic transplantation and mechanical circulatory support during the current coronavirus disease 2019 pandemic, we propose separating the effects of the pandemic into 5 distinct stages from a healthcare system perspective. We discuss how the classical ethical principles of utility, justice, and efficiency may need to be adapted, and we give specific recommendations for thoracic transplantation and mechanical circulatory support centers to balance their clinical decisions and strategies for advanced heart and lung disease during the current pandemic.

Stroke is a devastating morbidity associated with left ventricular assist device (LVAD) support. We report a comprehensive analysis of stroke subtypes in the ENDURANCE destination therapy (DT) and ENDURANCE Supplemental (DT2) trials.Patients in the combined HeartWare LVAD (HVAD) cohorts of the DT and DT2 trials were included. Neurologic events included ischemic stroke (ischemic cerebrovascular accident [ICVA]), hemorrhagic stroke (hemorrhagic cerebrovascular accident [HCVA]), and transient ischemic attack (TIA). Peri-operative strokes were defined as occurring within 2 weeks of the implant.A total of 604 patients received an HVAD in the DT (n = 296) and DT2 (n = 308) trials. Over 2 years, 178 (29.5%) had at least 1 cerebrovascular accident (CVA). Forty-four (7.3%) had HCVAs, 116 (19.2%) had ICVAs, and 44 (7.3%) had TIAs. Thirty (5.0%) had peri-operative stroke. In multivariable analysis, sub-therapeutic international normalized ratio (INR) values were independently associated with peri-operative stroke. Supra- and/or sub-therapeutic INR values, peripheral vascular disease, and presence of left ventricular thrombus were independently associated with ICVA. No aspirin and supra- and/or sub-therapeutic INR values were independently associated with TIA. No aspirin, supra- and/or sub-therapeutic INR values, and prior stroke and/or TIA were associated with HCVA. In further analysis, mean arterial pressure (MAP) was higher in the ICVA (86.8mm Hg, p = 0.002 4) and TIA (88.8mm Hg, p0.0001) groups, but not in HCVA, than in the No-CVA group (81.4mm Hg). Time in therapeutic range for INR was 65.3% for the No-CVA group, 62.9% (p = 0.59) for HCVA, 65.1% (p = 0.97) for ICVA, and 63.2% (p = 0.62) for TIA.Supra- and sub-therapeutic INR values at the time of CVA were associated with all stroke subtypes14 days post-implant. MAP was higher among those with ICVA and TIA but not with HCVA compared to without CVA. Our study demonstrates the challenges of anti-thrombotic therapy and blood pressure management in LVAD population.

Background Heart transplantation is a life-saving procedure that has seen improvements in transplant and patient outcomes due to advances in immunosuppression and prevention of posttransplantation infectious episodes (IEps). This study systematically evaluates IEps in the modern era of heart transplantation at Stanford University Medical Center. Methods This is a single-center retrospective review that includes 279 consecutive adult heart transplantation recipients from January 2008 to September 2017. Baseline demographic, clinical, serological, and outcomes information were collected. Kaplan-Meier estimator was used to assess survival stratified by IEp occurrence within the first year. Results A total of 600 IEps occurred in 279 patients (2.15 IEps per patient) during a median follow-up period of 3 years. Overall survival was 83.3% (95% confidence interval [CI], 76.2-88.4) at 1 year posttransplantation for those with any IEp compared with 93.0% (95% CI, 87.2-96.4) in those without IEp (P = 0.07). Bacterial IEps were the most common (n = 375; 62.5%), followed by viral (n = 180; 30.0%), fungal (n = 40; 6.7%), and parasitic (n = 5; 0.8%). IEps by Gram-negative bacteria (n = 210) outnumbered those by Gram-positive bacteria (n = 142). Compared with prior studies from our center, there was a decreased proportion of viral (including cytomegalovirus), fungal (including Aspergillus spp. and non-Aspergillus spp. molds), and Nocardia infections. There were no IEps due to Mycobacterium tuberculosis, Pneumocystis jirovecii, or Toxoplasma gondii. Conclusions A significant reduction in viral, fungal, and Nocardia IEps after heart transplantation was observed, most likely due to advancements in immunosuppression and preventive strategies, including pretransplant infectious diseases screening and antimicrobial prophylaxis.

The left ventricular assist device (LVAD) is an established treatment for select patients with end-stage heart failure. Some patients recovered and are considered for explantation. Assessing recovery involves exercise testing and echo ramping on full and minimal LVAD support. Combined cardiopulmonary exercise testing with simultaneous echo ramping (CPET-R) has not been well studied. Patients were included if they had CPET within the previous 6 months, were clinically stable, and had an INR2.0 on the day of examination. Patients had CPET-R on two occasions within 14 days: (a) with LVAD at therapeutic speed and (b) with LVAD at the lowest speed possible. Six patients were between 29 and 75 years (two female). One patient did not complete a turn-down test due to evidence of ischemia on initial CPET-R subsequently confirmed as a significant coronary artery stenosis on angiography. There were no significant differences in CPET or echo metrics between LVAD speeds. Two patients were explanted due to presumed LV recovery and remained event free for 30 and 47 months, respectively. Serial CPET-R seems safe and feasible for the evaluation of LV and global function and may result in improved clinical decision making for LVAD explantation.

Diabetes mellitus (DM) is common among recipients of heart transplantation (HTx) but its impact on clinical outcomes is unclear. We evaluated the associations between pretransplant DM and posttransplant DM (PTDM) and outcomes among adults receiving HTx at a single center.We performed a retrospective study (range 01/2008 - 07/2018), n = 244. The primary outcome was survival; secondary outcomes included acute rejection, cardiac allograft vasculopathy, infection requiring hospitalization, macrovascular events, and dialysis initiation post-transplant. Comparisons were performed using Kaplan-Meier and multivariable Cox regression analyses.Pretransplant DM was present in 75 (30.7%) patients and was associated with a higher risk for infection requiring hospitalization (p 0.05), but not with survival or other outcomes. Among the 144 patients without pretransplant DM surviving to 1 year, 29 (20.1%) were diagnosed with PTDM at the 1-year follow-up. After multivariable adjustment, PTDM diagnosis at 1-year remained associated with worse subsequent survival (hazard ratio 2.72, 95% confidence interval 1.03-7.16). Predictors of PTDM at 1-year included cytomegalovirus seropositivity and higher prednisone dose ( 5 mg/day) at 1-year follow-up.Compared to HTx recipients without baseline DM, those with baseline DM have a higher risk for infections requiring hospitalization, and those who develop DM after HTx have worse survival.

Background: The COVID-19 pandemic has placed an unprecedented strain on the US healthcare system, greatly impacting transplant centers. Objective: The purpose of this survey was to evaluate the impact of the COVID-19 pandemic on the transplant pharmacist workforce. Methods: A survey was disseminated electronically to assess the impact of the COVID-19 pandemic on the transplant pharmacist workforce. Respondents were asked to give background regarding transplant center, patient, population, and departmental staffing. Results: There were 67 total respondents from 56 transplant centers. In response to the COVID-19 pandemic, 55% of centers reported stopping non-life saving transplants, and a majority (89%) stopped living donor transplants altogether. The banning of caregivers on-site during education, reduction of bedside education teaching, and cancelling of group teaching classes occurred at 46%, 40%, and 22% of centers, respectively. Consequently, 42% of pharmacists surveyed felt that their confidence in patient and caregiver’s understanding of medications had decreased since these changes have been implemented. Conclusions: Pharmacist perception of patient and caregiver understanding of transplant medications has decreased since before the COVID-19 pandemic. As health systems strategize resource allocation throughout the pandemic, the importance of patient education must be prioritized to sustain and improve transplant outcomes.

Background: Progressive aortic valve disease has remained a persistent cause of concern in patients with left ventricular assist devices. Aortic incompetence (AI) is a known predictor of both mortality and readmissions in this patient population and remains a challenging clinical problem. Methods: Ten left ventricular assist device patients with de novo aortic regurgitation and 19 control left ventricular assist device patients were identified. Three-dimensional models of patients’ aortas were created from their computed tomography scans, following which large-scale patient-specific computational fluid dynamics simulations were performed with physiologically accurate boundary conditions using the SimVascular flow solver. Results: The spatial distributions of time-averaged wall shear stress and oscillatory shear index show no significant differences in the aortic root in patients with and without AI (mean difference, 0.67 dyne/cm 2 [95% CI, −0.51 to 1.85]; P =0.23). Oscillatory shear index was also not significantly different between both groups of patients (mean difference, 0.03 [95% CI, −0.07 to 0.019]; P =0.22). The localized wall shear stress on the leaflet tips was significantly higher in the AI group than the non-AI group (1.62 versus 1.35 dyne/cm 2 ; mean difference [95% CI, 0.15–0.39]; P P =0.17). Conclusions: Computational fluid dynamics serves a unique role in studying the hemodynamic features in left ventricular assist device patients where 4-dimensional magnetic resonance imaging remains unfeasible. Contrary to the widely accepted notions of highly disturbed flow, in this study, we demonstrate that the aortic root is a region of relatively stagnant flow. We further identified localized hemodynamic features in the aortic root that challenge our understanding of how AI develops in this patient population.

BACKGROUND Cardiac retransplantation accounts for approximately 3% of cardiac transplantation and is considered a risk factor for increased mortality. However, factors inherent to retransplantation including previous sternotomy, sensitization, and renal dysfunction may account for the increased mortality. We assessed whether retransplantation was associated with all-cause mortality after adjusting for such patient risk factors. METHODS We conducted a retrospective cohort study of adult and pediatric patients enrolled in the United Network for Organ Sharing database. We identified patients undergoing cardiac retransplantation based on transplant listing diagnosis and history of previous transplant. We used propensity-score matching to identify a matched cohort undergoing initial heart transplantation. RESULTS In total, 62,112 heart transplant recipients were identified, with a mean age 46.6 ± 19.1 years. Of these, 2,202 (3.4%) underwent late cardiac retransplantation (>1 year after initial transplant and not for acute rejection). Compared with a matched group of patients undergoing initial heart transplantation, patients undergoing late retransplantation had comparable rates of all-cause mortality at 1 year (13.6% vs 13.8%, p = 0.733). In addition, overall mortality was not significantly different after matching (unadjusted hazard ratio [HR] 1.08, p = 0.084). In contrast, patients undergoing retransplantation within 1 year of initial transplant or for acute rejection remained at increased risk of mortality post-transplant after similar matching (unadjusted HR 1.79, p CONCLUSIONS After matching for comorbidities, late retransplantation in the adult population was not associated with an increase in all-cause mortality. Our findings highlight the importance of assessing indication acuity and comorbid conditions when considering retransplant candidacy.

Current risk stratification models to predict outcomes after a left ventricular assist device (LVAD) are limited in scope. We assessed the performance of Bayesian models to stratify post-LVAD mortality across various International Registry for Mechanically Assisted Circulatory Support (INTERMACS or IM) Profiles, device types, and implant strategies. We performed a retrospective analysis of 10,206 LVAD patients recorded in the IM registry from 2012 to 2016. Using derived Bayesian algorithms from 8,222 patients (derivation cohort), we applied the risk-prediction algorithms to the remaining 2,055 patients (validation cohort). Risk of mortality was assessed at 1, 3, and 12 months post implant according to disease severity (IM profiles), device type (axial versus centrifugal) and strategy (bridge to transplantation or destination therapy). Fifteen percentage (n = 308) were categorized as IM profile 1, 36% (n = 752) as profile 2, 33% (n = 672) as profile 3, and 15% (n = 311) as profile 4-7 in the validation cohort. The Bayesian algorithms showed good discrimination for both short-term (1 and 3 months) and long-term (1 year) mortality for patients with severe HF (Profiles 1-3), with the receiver operating characteristic area under the curve (AUC) between 0.63 and 0.74. The algorithms performed reasonably well in both axial and centrifugal devices (AUC, 0.68-0.74), as well as bridge to transplantation or destination therapy indication (AUC, 0.66-0.73). The performance of the Bayesian models at 1 year was superior to the existing risk models. Bayesian algorithms allow for risk stratification after LVAD implantation across different IM profiles, device types, and implant strategies.

The risk of infection after heart transplantation is highest within the first year and represents the leading cause of early mortality. In this cohort of patients enrolled in the Outcomes AlloMap Registry (OAR), we sought to describe infection episodes (IEp) resulting in hospitalization, in the early (1 year) and late (≥1 year) post-transplant period and determine the impact of immunosuppression on incidence of infection.The primary aim was to assess the incidence and nature of IEp. The secondary aim was to evaluate the effect of potential risk factors, such as recipient age; sex; body mass index; panel-reactive antibodies; cytomegalovirus (CMV) primary mismatch; prednisone, tacrolimus, and sirolimus levels; and gene expression profile (GEP) score, in the development of IEp.The OAR comprises 1,504 patients, of whom 220 patients (14.6%) had an IEp during a median follow-up period of 382 days (interquartile range [IQR] 230 to 579 days). The cause-specific 5-year hazard ratio for any infection was 2.029 (p = 0.12). The pattern of early infection was consistent with nosocomial and opportunistic causes, whereas later infection was consistent with late-onset opportunistic and community-acquired etiologies. Sixty-two percent of the infections occurred early. In the time-dependent analysis, higher prednisone dose (log prednisone, hazard ratio [HR] 1.30, p = 0.022) was the most significant risk factor for all IEp.In the OAR cohort, the majority of infections occurred within 1 year after transplantation. Clinicians may consider more aggressive prednisone withdrawal in low-risk patients to reduce IEp.

BACKGROUND Some literature exists potentially linking proliferation signal inhibitors (PSIs) to venous thromboembolism (VTE). We sought to determine the impact of PSIs on development of VTE in heart transplant (HT) patients while controlling for other risk factors. METHODS The incidence and predisposing factors of VTE were analyzed in this retrospective review of patients >18 years who underwent HT January 2000 to October 2016. Re-transplants, multiorgan transplants, or patients that expired within 30 days post-HT were excluded. VTE incidence rates are reported as number of events per 100 person-years. Cox proportional hazards models were used to assess the relationship between PSI exposure (time-varying covariate) and VTE. RESULTS Of 561 HT recipients, 112 received PSIs, started a median of 1.5 years post-HT. There were 102 total VTE events: 78 in PSI-naive patients during 2,547 patient-years (3.0 events per 100 person-years) vs 24 in PSI-exposed patients during 544 patient-years (4.4 events per 100 person-years). Cox proportional hazards models with PSI exposure as a time-varying covariate indicated the increased risk was statistically significant (unadjusted hazard ratio [HR] 2.14, 95% confidence interval [CI] 1.31 to 3.49, p = 0.002). A VTE history was significantly associated with increased risk of VTE post-HT (HR 1.58, 95% CI 1.07 to 2.35, p = 0.022); however, the risk remained significant when adjusting for potential confounders, including previous VTE (HR 2.0, 95% CI 1.18 to 3.38, p = 0.010). CONCLUSIONS Exposure to PSIs is associated with a significant increase in risk for VTE even when controlling for other risk factors. When considering the use of PSI-based immunosuppression after HT, the risk of VTE over time should be weighed against the potential benefit.

BACKGROUND The outlook for ambulatory patients with advanced heart failure (HF) and the appropriate timing for left ventricular assist device (LVAD) or transplant remain uncertain. The aim of this study was to better understand disease trajectory and rates of progression to subsequent LVAD therapy and transplant in ambulatory advanced HF. METHODS See Related Editorial, page XXX Patients with advanced HF who were New York Heart Association (NYHA) Class III or IV and Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) Profiles 4 to 7, despite optimal medical therapy (without inotropic therapy), were enrolled across 11 centers and followed for the end-points of survival, transplantation , LVAD placement, and health-related quality of life. A secondary intention-to-treat survival analysis compared outcomes for MedaMACS patients with a matched group of Profile 4 to 7 patients with LVADs from the INTERMACS registry. RESULTS Between May 2013 and October 2015, 161 patients were enrolled with INTERMACS Profiles 4 (12%), 5 (32%), 6 (49%), and 7 (7%). By 2 years after enrollment, 75 (47%) patients had reached a primary end-point with 39 (24%) deaths, 17 (11%) undergoing LVAD implantation, and 19 (12%) receiving a transplant. Compared with 1,753 patients with Profiles 4 to 7 receiving LVAD therapy, there was no overall difference in intention-to-treat survival between medical and LVAD therapy, but survival with LVAD therapy was superior to medical therapy among Profile 4 and 5 patients (p = 0.0092). Baseline health-related quality of life was lower among patients receiving a LVAD than those enrolled on continuing oral medical therapy, but increased after 1 year for survivors in both cohorts. CONCLUSIONS Ambulatory patients with advanced HF are at high risk for poor outcomes, with only 53% alive on medical therapy after 2 years of follow-up. Survival was similar for medical and LVAD therapy in the overall cohort, which included the lower severity Profiles 6 and 7, but survival was better with LVAD therapy among patients in Profiles 4 and 5. Given the poor outcomes in this group of advanced HF patients, timely consideration of transplant and LVAD is of critical importance.

Randomized controlled trials can provide optimal clinical evidence to assess the benefits of new devices, and it is these data that often shape device usage in real-world practice. However, individual clinical trial results sometimes appear discordant for the same device, and alternative devices are sometimes not employed in similar patient populations. To make sound evidence-based decisions, clinicians routinely rely on cross-trial comparisons from different trials of similar but not identical patient populations to assess competing technology when head-to-head randomized comparisons are unavailable.

Right heart failure (RHF) after left ventricular assist device (LVAD) implantation is associated with high morbidity and mortality. Existing risk scores include semiquantitative evaluation of right ventricular (RV) dysfunction. This study aimed to determine whether quantitative evaluation of both RV size and function improve risk stratification for RHF after LVAD implantation beyond validated scores.From 2009 to 2015, 158 patients who underwent implantation of continuous-flow devices who had complete echocardiographic and hemodynamic data were included. Quantitative RV parameters included RV end-diastolic (RVEDAI) and end-systolic area index, RV free-wall longitudinal strain (RVLS), fractional area change, tricuspid annular plane systolic excursion, and right atrial area and pressure. Independent correlates of early RHF (30 days) were determined with the use of logistic regression analysis. Mean age was 56 ± 13 years, with 79% male; 49% had INTERMACS profiles ≤2. RHF occurred in 60 patients (38%), with 20 (13%) requiring right ventricular assist device. On multivariate analysis, INTERMACS profiles (adjusted odds ratio 2.38 [95% confidence interval [CI] 1.47-3.85]), RVEDAI (1.61 [1.08-2.32]), and RVLS (2.72 [1.65-4.51]) were independent correlates of RHF (all P.05). Both RVLS and RVEDAI were incremental to validated risk scores (including the EUROMACS score) for early RHF after LVAD (all P.01).RV end-diastolic and strain are complementary prognostic markers of RHF after LVAD implantation.

Background The advent of direct-acting antiviral therapy for Hepatitis C (HCV) has made using HCV-viremic donors a viable strategy to address the donor shortage in heart transplantation . We employed a large-scale simulation to evaluate the impact and cost-effectiveness of using HCV-viremic donors for heart transplant . Methods We simulated detailed histories from time of listing until death for the real-world cohort of all adults listed for heart transplant in the United States from July 2014 to June 2019 (n = 19,346). This population was imputed using historical data and captures “real-world” heterogeneity in geographic and clinical characteristics. We estimated the impact of an intervention in which all candidates accept HCV+ potential donors (n = 472) on transplant volume, waitlist outcomes, and lifetime costs and quality-adjusted life years (QALYs). Results The intervention produced 232 more transplants, 132 fewer delistings due to deterioration, and 50 fewer waitlist deaths within this 5-year cohort and reduced wait times by 3% to 11% (varying by priority status). The intervention was cost-effective, adding an average of 0.08 QALYs per patient at a cost of $124 million ($81,892 per QALY). DAA therapy and HCV care combined account for 11% this cost, with the remainder due to higher costs of transplant procedures and routine post-transplant care. The impact on transplant volume varied by blood type and region and was correlated with donor-to-candidate ratio (ρ = 0.71). Conclusions Transplanting HCV+ donor hearts is likely to be cost-effective and improve waitlist outcomes, particularly in regions and subgroups experiencing high donor scarcity.

Background COVID-19 continues to inflict significant morbidity and mortality, particularly on patients with preexisting health conditions. The clinical course, outcomes, and significance of immunosuppression regimen in heart transplant recipients with COVID-19 remains unclear. Methods We included the first 99 heart transplant recipients at participating centers with COVID-19 and followed patients until resolution. We collected baseline information, symptoms, laboratory studies, vital signs, and outcomes for included patients. The association of immunosuppression regimens at baseline with severe disease were compared using logistic regression , adjusting for age and time since transplant. Results The median age was 60 years, 25% were female, and 44% were white. The median time post-transplant to infection was 5.6 years. Overall, 15% died, 64% required hospital admission, and 7% remained asymptomatic. During the course of illness, only 57% of patients had a fever, and gastrointestinal symptoms were common. Tachypnea , oxygen requirement, elevated creatinine and inflammatory markers were predictive of severe course. Age ≥ 60 was associated with higher risk of death and the use of the combination of calcineurin inhibitor , antimetabolite , and prednisone was associated with more severe disease compared to the combination of calcineurin inhibitor and antimetabolite alone (adjusted OR = 7.3, 95% CI 1.8-36.2). Among hospitalized patients, 30% were treated for secondary infection, acute kidney injury was common and 17% required new renal replacement therapy . Conclusions We present the largest study to date of heart transplant patients with COVID-19 showing common atypical presentations and a high case fatality rate of 24% among hospitalized patients and 16% among symptomatic patients.

Non-invasive and cost effective in nature, the echocardiogram allows for a comprehensive assessment of the cardiac musculature and valves. Despite progressive improvements over the decades, the rich temporally resolved data in echocardiography videos remain underutilized. Human reads of echocardiograms reduce the complex patterns of cardiac wall motion, to a small list of measurements of heart function. Furthermore, all modern echocardiography artificial intelligence (AI) systems are similarly limited by design - automating measurements of the same reductionist metrics rather than utilizing the wealth of data embedded within each echo study. This underutilization is most evident in situations where clinical decision making is guided by subjective assessments of disease acuity, and tools that predict disease onset within clinically actionable timeframes are unavailable. Predicting the likelihood of developing post-operative right ventricular failure (RV failure) in the setting of mechanical circulatory support is one such clinical example. To address this, we developed a novel video AI system trained to predict post-operative right ventricular failure (RV failure), using the full spatiotemporal density of information from pre-operative echocardiography scans. We achieve an AUC of 0.729, specificity of 52% at 80% sensitivity and 46% sensitivity at 80% specificity. Furthermore, we show that our ML system significantly outperforms a team of human experts tasked with predicting RV failure on independent clinical evaluation. Finally, the methods we describe are generalizable to any cardiac clinical decision support application where treatment or patient selection is guided by qualitative echocardiography assessments., 12 pages, 3 figures

The left ventricular assist device (LVAD) is an established treatment for select patients with end-stage heart failure. Some patients recovered and are considered for explantation. Assessing recovery involves exercise testing and echo ramping on full and minimal LVAD support. Combined cardiopulmonary exercise testing with simultaneous echo ramping (CPET-R) has not been well studied. Patients were included if they had CPET within the previous 6 months, were clinically stable, and had an INR >2.0 on the day of examination. Patients had CPET-R on two occasions within 14 days: (a) with LVAD at therapeutic speed and (b) with LVAD at the lowest speed possible. Six patients were between 29 and 75 years (two female). One patient did not complete a turn-down test due to evidence of ischemia on initial CPET-R subsequently confirmed as a significant coronary artery stenosis on angiography. There were no significant differences in CPET or echo metrics between LVAD speeds. Two patients were explanted due to presumed LV recovery and remained event free for 30 and 47 months, respectively. Serial CPET-R seems safe and feasible for the evaluation of LV and global function and may result in improved clinical decision making for LVAD explantation.

Donor and recipient size matching during heart transplant can be assessed using weight or predicted heart mass (PHM) ratios. We developed sex-specific allomteric equations for PHM and predicted lean body mass (PLBM) using the United Kingdom Biobank (UKB) and evaluated their predictive value in the United Network of Organ Sharing database. Donor and recipient size matching was based on weight, PHM and PLBM ratios. PHM was calculated using the Multiethnic Study of Atherosclerosis and UKB equations. PLBM was calculated using the UKB and National Health and Nutrition Examination Survey equations. Relative prognostic utility was compared using multivariable Cox analysis, adjusted for predictors of 1-year survival in the Scientific Registry of Transplant Recipients model. Of 53,648 adult patients in the United Network of Organ Sharing database between 1996 and 2016, 6528 (12.2%) died within the first year. In multivariable analysis, undersized matches by any metric were associated with increased 1-year mortality (all P0.01). Oversized matches were at increased risk using PHM or PLBM (all P0.01), but not weight ratio. There were significant differences in classification of size matching by weight or PHM in sex-mismatched donor-recipient pairs. A significant interaction was observed between pulmonary hypertension and donor undersizing (hazard ratio 1.15, P = 0.026) suggesting increased risk of undersizing in pulmonary hypertension. Donor and recipient size matching with simplified PHM and PLBM offered an advantage over total body weight and may be more important for sex-mismatched donor-recipient pairs. Donor undersizing is associated with worse outcomes in patients with pulmonary hypertension.

Introduction: Post-operative right ventricular failure (RV failure) is the single largest contributor to short-term mortality in patients with left ventricular assist devices (LVAD); yet predicting which patient is at risk of developing this complication in the pre-operative setting has remained beyond the abilities of experts in the field. We hypothesized that deep artificial intelligence (AI) driven characterization of subtle pre-operative myocardial motion features, could predict post-operative RV failure in LVAD patients. Methods: We developed a novel echocardiography AI system using an improved dense trajectory algorithm that tracks motion vectors in an unsupervised fashion, and a 3-dimensional convolutional neural network that tracks spatiotemporal features from videos. We used pre-operative ECHO videos from a 536 patient multicenter echocardiographic and clinical dataset, and via a standard 10-fold cross validation, trained and validated the AI system to predict severe or higher grades of post-operative RV failure at the time of index hospitalization. Finally, we independently benchmarked our AI system against clinicians equipped with contemporary clinical risk scores to predict post-operative RV failure (Penn and CRITT score) and manually derived echocardiographic metrics of RV function. Results: 173 (32%) patients were adjudicated to have severe post-operative RV failure. The area under the receiver operator characteristic curve (AUC ROC) for the AI system was 0.86 (95% CI 0.824-0.896). The performance of our AI system exceeded that of both the best performing clinical risk score and manually derived echocardiographic metric by a significant margin (ΔAUC +0.30, 95% CI 0.27 - 0.33 and ΔAUC +0.24, 95% CI 0.21 - 0.27; both p &lt 0.0001). Conclusions: A novel ECHO AI system trained and validated on a multicenter dataset outperformed clinical experts equipped with both contemporary risk scores and manually calculated echocardiographic metrics.

Introduction: Improvement in social functioning is an important goal for advanced heart failure (HF) patients (pts) who receive left ventricular assist devices (LVADs). Self-reported social functioning and its association with clinical change is understudied. Methods: Adult HF pts who received LVADs at nine U.S. sites completed two measures of social functioning prior to, and 3-6 months after, surgery. Patient-Reported Outcomes Measurement Information System (PROMIS) measures were: Ability to Participate in Social Roles and Activities (Ability) and Satisfaction with Social Roles and Activities (Satisfaction). PROMIS uses T-scores standardized to a U.S. general population (mean=50; standard deviation, SD=10); higher scores represent better outcomes. New York Heart Association (NYHA) Functional Classification was assigned at both times by treating clinicians; change was subsequently categorized as Better, Same or Worse NYHA. Linear mixed effects models and least-squares means were estimated for Ability and Satisfaction. Results: Pts ( n =107) were primarily male (78%) and non-Hispanic White (68%); mean age (SD)=54 (12.5) years; 74% were NYHA Class IV prior to surgery and only 18% were NYHA IV at follow-up. NYHA was better for the majority ( n =75, 70%); 24% ( n =26) were the same, and 6% ( n =6) were worse. Mean Ability and Satisfaction were lower than the general population mean of 50 at both time points (Figure). Ability improved for the NYHA Better ( p p =0.030) groups, and nominally decreased for the Worse group ( p =0.800). Satisfaction improved for the Better ( p p >0.300). Conclusions: Self-reported social functioning measures were responsive to clinician-rated clinical change. Understanding these relationships may guide clinicians in providing targeted health-related quality of life therapies to improve social functioning.

We evaluated post-heart transplant (HTx) outcomes after use of higher-risk donor hearts for candidates supported with pre-HTx mechanical circulatory support (MCS).In this retrospective analysis of the national United Network for Organ Sharing registry, a total of 9,915 adult candidates on MCS underwent HTx from January 1, 2010 to March 31, 2019. Multi-organ, re-transplant, and congenital heart disease patients were excluded. Higher-risk donor organs met at least one of the following criteria: left ventricular ejection fraction50%, donor to recipient predicted heart mass ratio0.86, donor age55 years, or ischemic time4 hours. Primary outcome was 1 year post-transplant survival.Among HTx recipients, 3688 (37.2%) received higher-risk donor hearts. Candidates supported with pre-HTx extracorporeal membrane oxygenation or biventricular assist device (n = 374, 3.8%) who received higher-risk donor hearts had comparable 1 year survival (HR: 1.14, 95% CI: [0.67-1.93], p = 0.64) to recipients of standard-risk donor hearts, when adjusted for recipient age and sex. In candidates supported with intra-aortic balloon pump (n = 1391, 14.6%), transplantation of higher-risk donor hearts did not adversely affect 1 year survival (HR: 0.80, 95% CI: [0.52-1.22], p = 0.30). Patients on durable left ventricular assist devices (LVAD) who received higher-risk donor hearts had comparable 1 year survival to continued LVAD support on the waitlist, but mortality was increased compared to those who received standard-risk donor hearts (HR: 1.37, 95% CI: [1.11-1.70], p = 0.004).Patients requiring pre-HTx temporary MCS who received higher-risk donor hearts had comparable 1 year post-transplant survival to those who received standard-risk donor hearts. Stable patients on durable LVADs may benefit from waiting for standard-risk donor hearts.

Left ventricular assist devices (LVADs) have consistently and successfully improved mortality associated with end-stage heart failure. However, the definition of an "optimal" outcome post LVAD as a benchmark remains debatable. We retrospectively examined patients in the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) between 2012 and 2016 to assess 1 year post-LVAD "optimal outcome" defined as a patient who was alive on device or transplanted, New York Heart Association functional class I/II, had no more than 2 hospitalizations at year 1, and no major adverse event. We identified the features predicting a nonoptimal outcome at 1 year. Finally, we focused on 3 years outcomes in patients implanted as destination therapy. Of the 12,566 patients in INTERMACS who received an LVAD, only 3,495 (27.8%) met our definition of optimal LVAD outcome at 1 year. These patients tended to be younger, male, and were four times more likely to be supported as bridge to transplantation. For those with optimal outcome at year 1, their chances of long-term survival were better than those who were alive at year 1, but did not meet criteria for an optimal outcome. In the destination therapy population, only 14% of patients met the definition of an optimal outcome at 3 years. Despite significantly improved survival in patients with end-stage heart failure treated with LVAD therapy, majority patients had nonoptimal outcomes at 1 and 3 years post implant, by our definition. There is a pressing need to create a benchmark to define optimal outcomes post LVAD, both in our clinical trials and practice.

Cytomegalovirus (CMV) infection has been implicated in the pathogenesis of allograft rejection in heart transplant (HT) recipients. The effect of a CMV infection on the gene expression profiling (GEP, AlloMap) scores in the absence of acute rejection is not known.Data from 14,985 samples collected from 2,288 adult HT recipients enrolled in Outcomes AlloMap Registry were analyzed. Patients with known CMV serology at the time of HT who had at least 1 AlloMap score reported during follow-up were included. AlloMap scores for those patients with CMV (but no ongoing rejection) were compared with those who were never infected. An exploratory analysis on the impact of CMV on available donor-derived cell-free DNA (AlloSure) was also performed.A total of 218 patients (10%) were reported to have CMV infection after transplantation. AlloMap score in those samples with CMV infection (n = 311) had a GEP score (34; range: 29-36) significantly higher than the GEP score from samples (n = 14,674) obtained in the absence of CMV infection (30; range: 26-34; p0.0001). Both asymptomatic viremia and CMV disease demonstrated significantly higher AlloMap scores than no CMV infection samples (median scores: 33, 35, and 30, respectively; p0.0001). AlloSure levels, available for 776 samples, were not significantly different (median: 0.23% in 18 samples with CMV infection vs 0.15% in 776 samples without CMV infection; p = 0.66).CMV infection in HT recipients is associated with an increase in AlloMap score, whereas AlloSure results do not appear to be impacted. This information should be considered when clinically interpreting abnormal/high AlloMap scores in HT recipients.

In this study, we describe a novel ‘radiomics’ approach to an echocardiography artificial intelligence system that enables the extraction of hundreds of thousands of motion parameters per echocardiography video. We apply this AI system to the clinical problem of predicting post-operative right ventricular failure (RV failure) in heart failure patients receiving implantable circulatory life support systems. Post-operative RV failure is the single largest contributor to short-term mortality in patients with left ventricular assist devices (LVAD); yet predicting which patient is at risk of developing this complication in the pre-operative setting, has remained beyond the abilities of experts in the field. We report results on testing datasets using a standard 10-fold cross validation. The AUC for the AI system trained using the Stanford LVAD dataset was 0.860 (95% CI 0.815-0.905; n = 290 patients) using pre-operative echocardiograms alone. We further show that our system outperforms board certified clinicians equipped with both contemporary risk scores (AUC 0.502 - 0.584) and independently measured echocardiographic metrics (0.519 – 0.598).

BACKGROUND Currently, there are no simple tools to evaluate the acute heart failure (HF) symptom severity in children hospitalized with acute decompensated HF (ADHF). We sought to develop an inpatient HF score (HFS) that could be used as a clinical tool and for clinical trials. METHODS Pediatric HF clinicians at Stanford reviewed the limitations of existing HFSs, which include lack of calibration to the inpatient setting, omission of gastrointestinal symptoms, need for multiple age-based tools, and scores that prioritize treatment intensity over patient symptoms. To address these, we developed an acute HFS corresponding to the 3 cardinal symptoms of HF: difficulty with breathing, feeding, and activity. The score was iteratively improved over a 3-year pilot phase until no further changes were made. The inter-rater reliability (IRR) across a range of providers was assessed using the final version. Peak HFSs were analyzed against mortality and length of stay (LOS) for all pediatric HF discharges between July and October 2019. RESULTS The final HFS was a 4-point ordinal severity score for each of the 3 symptom domains (total score 0-12). Among clinicians who scored 12 inpatients with ADHF simultaneously, the intraclass correlation (ICC) was 0.94 (respiratory ICC = 0.89, feeding ICC = 0.85, and activity ICC = 0.80). Score trajectory reflected our clinical impression of patient response to HF therapies across a range of HF syndromes including 1- and 2-ventricle heart disease and reduced or preserved ejection fraction. Among the 28 patients hospitalized during a 3-months period (N = 28), quartiles of peak score were associated with LOS (p < 0.01) and in-hospital mortality (p < 0.01): HFS 0 to 3 (median LOS of 5 days and mortality of 0%), HFS 4 to 6 (median LOS of 18 days and mortality of 0%), HFS 5 to 9 (median LOS of 29 days and mortality of 23%), and HFS 10 to 12 (median LOS of 121 days and mortality of 50%). CONCLUSION This simple acute HFS may be a useful tool to quantify and monitor day-to-day HF symptoms in children hospitalized with ADHF regardless of etiology or age group. The score has excellent IRR across provider levels and is associated with major hospital outcomes supporting its clinical validity. Validation in a multicenter cohort is warranted.

Importance The new United Network for Organ Sharing (UNOS) donor heart allocation system gives priority to patients supported with nondischargeable mechanical circulatory support (MCS) devices while awaiting heart transplant. Whether there has been a change in temporary MCS use in cardiac intensive care units (CICUs) since the implementation of this policy is unknown. Objectives To examine whether the UNOS donor heart allocation system revision in October 2018 was associated with changes in temporary MCS use in CICUs and whether temporary MCS use differed between US transplant centers and US nontransplant centers and Canadian centers. Design, Setting, and Participants In this cohort study, 14 centers from the Critical Care Cardiology Trials Network (CCCTN), a multicenter network of tertiary CICUs in North America, contributed 2-month snapshots of consecutive medical CICU admissions between September 1, 2017, and September 1, 2018 (prerevision period), and October 1, 2018, and September 1, 2019 (postrevision period). CICUs were classified as US transplant centers (n = 7) or other CICUs (US nontransplant centers or Canadian centers; n = 7). Exposure Revision to the UNOS donor heart allocation system. Main Outcomes and Measures Treatment with temporary MCS (intra-aortic balloon pump, microaxial intracardiac ventricular assist device, percutaneous centrifugal ventricular assist device, venoarterial extracorporeal membrane oxygenation, or surgically implanted, nondischargeable MCS device) during hospital admission. Results A total of 384 admissions for acute, decompensated, heart failure–related cardiogenic shock (ADHF-CS) were included, among which 248 (64.6%) were to US transplant centers; 126 admissions (51%) were in the prerevision period and 122 (49%) were in the postrevision period. The mean (SD) patient age was 61.2 (14.6) years; 246 patients (64.1%) were male. The proportion of admissions with ADHF-CS managed with temporary MCS at US transplant centers significantly increased from 25.4% (32 of 126 admissions) before to 42.6% (52 of 122 admissions) after the UNOS allocation system changes (P = .004). In other CICUs, the proportion did not significantly change (24.5% [13 of 53 admissions] to 24.1% [20 of 83 admissions];P = .95). After multivariable adjustment, patients admitted to US transplant centers in the postrevision period were more likely to receive temporary MCS compared with those admitted in the prerevision period (adjusted odds ratio, 2.19; 95% CI, 1.13-4.24;P = .02). Conclusions and Relevance In the year after implementation of the new UNOS donor heart allocation system, temporary MCS use in patients admitted with ADHF-CS increased in US transplant centers but not in other CICUs. Whether this shift in practice will affect outcomes of patients with ADHF-CS or organ distribution should be evaluated.

As the medical community is increasingly offering transplantation to patients with increasing comorbidity burdens, the number of simultaneous heart-kidney (SHK) transplants is rising in the United States. How to determine eligibility for SHK transplant versus heart transplant alone is unknown. In this review, we situate this problem in the broader picture of organ shortage. We critically appraise available literature on outcomes in SHK versus heart transplant alone. We posit staged kidney-after-heart transplantation as a plausible alternative to SHK transplantation and review the pros and cons. Drawing lessons from the field of simultaneous liver-kidney transplant, we argue for an analogous policy for SHK transplant with standardized minimal eligibility criteria and a modified Safety Net provision. The new policy will serve as a starting point for comparing simultaneous versus staged approaches and refining the medical eligibility criteria for SHK.