Evaluation of veteran community care outcomes after coronary artery bypass grafting: a retrospective pilot cohort.

For Veterans who cannot be seen in a timely fashion or must travel long distances to be seen, the Veterans Health Administration (VHA) offers funded care in the community. The use of this program has rapidly increased; however, there have been no systematic evaluations of surgery specific metrics such as perioperative complications, mortality and timeliness of care. To evaluate this in cardiac surgery patients, we compared veterans undergoing coronary artery bypass grafting in the community to those remaining within the VHA. We identified 78 patients during calendar year 2018 meeting inclusion criteria. 41 underwent surgery in the community versus 37 in the VHA. There were no significant differences in baseline demographics including age, sex, race, ethnicity, comorbidities and surgical risk scores. With regard to perioperative outcomes, veterans who underwent surgery within the VHA had lower infection rates (17% vs. 0%, p = 0.008) and 30-day emergency department utilization (22% vs. 5%, p = 0.04). A longer median postoperative inpatient stay was also seen within the VHA (8 days vs. 6 days, p < 0.001). These findings suggest that the VHA may better serve Veterans and prevent adverse events after CABG, at the expense of prolonged hospitalization. More study is needed to validate the findings of this pilot study.

Can Artificial Intelligence Improve the Readability of Patient Education Materials on Aortic Stenosis? A Pilot Study.

INTRODUCTION: The advent of generative artificial intelligence (AI) dialogue platforms and large language models (LLMs) may help facilitate ongoing efforts to improve health literacy. Additionally, recent studies have highlighted inadequate health literacy among patients with cardiac disease. The aim of the present study was to ascertain whether two freely available generative AI dialogue platforms could rewrite online aortic stenosis (AS) patient education materials (PEMs) to meet recommended reading skill levels for the public. METHODS: Online PEMs were gathered from a professional cardiothoracic surgical society and academic institutions in the USA. PEMs were then inputted into two AI-powered LLMs, ChatGPT-3.5 and Bard, with the prompt "translate to 5th-grade reading level". Readability of PEMs before and after AI conversion was measured using the validated Flesch Reading Ease (FRE), Flesch-Kincaid Grade Level (FKGL), Simple Measure of Gobbledygook Index (SMOGI), and Gunning-Fog Index (GFI) scores. RESULTS: Overall, 21 PEMs on AS were gathered. Original readability measures indicated difficult readability at the 10th-12th grade reading level. ChatGPT-3.5 successfully improved readability across all four measures (p < 0.001) to the approximately 6th-7th grade reading level. Bard successfully improved readability across all measures (p < 0.001) except for SMOGI (p = 0.729) to the approximately 8th-9th grade level. Neither platform generated PEMs written below the recommended 6th-grade reading level. ChatGPT-3.5 demonstrated significantly more favorable post-conversion readability scores, percentage change in readability scores, and conversion time compared to Bard (all p < 0.001). CONCLUSION: AI dialogue platforms can enhance the readability of PEMs for patients with AS but may not fully meet recommended reading skill levels, highlighting potential tools to help strengthen cardiac health literacy in the future.

Prolonged travel time to transplantation center is associated with poor outcomes following heart transplantation.

BACKGROUND: This study aims to examine the impact of home-to-transplantation center travel time as a potential barrier to healthcare accessibility. METHODS: Observational study examined adult heart transplant recipients who received a graft between 2012 and 2022 in the United States. Travel time was calculated using the Google Distance Matrix API between the recipient's residence and transplantation center. A multivariable parametric survival model was fitted to minimize confounding bias. RESULTS: Among the 25,923 recipients that met the selection criteria, the median travel time was 51 â€‹min and 95 â€‹% of recipients lived within a 5-h radius of their center. White recipients experienced longer median travel times (62 â€‹min, p â€‹< â€‹0.001) compared to Black (36 â€‹min) or Hispanic (40 â€‹min) recipients. A travel time of 1-2 â€‹h (survival time ratio [STR] 0.867, p â€‹= â€‹0.035) or >2 â€‹h (STR 0.873, p â€‹= â€‹0.026) away from the transplantation center was independently associated with lower long-term survival rates. CONCLUSION: Extended travel times to transplantation centers may negatively impact long-term survival outcomes for heart transplant recipients, suggesting the need to address this potential barrier to healthcare accessibility.

Ventricular Remodeling Following Metabolic and Bariatric Surgery Decreases Need for Heart Transplantation: A Predictive Model.

PURPOSE: For patients with obesity and congestive heart failure (CHF) who require heart transplantation (HT), aggressive weight loss has been associated with ventricular remodeling, or subclinical alterations in left and right ventricular structure that affect systolic function. Many have suggested offering metabolic and bariatric surgery (MBS) for these patients. As such, we evaluated the role of MBS in HT for patients with obesity and CHF using predictive modelling techniques. MATERIALS AND METHODS: Markov decision analysis was performed to simulate the life expectancy of 30,000 patients with concomitant obesity, CHF, and 30% ejection fraction (EF) who were deemed ineligible to be waitlisted for HT unless they achieved a BMI < 35 kg/m2. Life expectancy following diet and exercise (DE), Roux-en-Y gastric bypass (RYGB), and sleeve gastrectomy (SG) was estimated. Base case patients were defined as having a pre-intervention BMI of 45 kg/m2. Sensitivity analysis of initial BMI was performed. RESULTS: RYGB patients had lower rates of HT and received HT quicker when needed. Base case patients who underwent RYGB gained 2.2 additional mean years survival compared with patients who underwent SG and 10.3 additional mean years survival compared with DE. SG patients gained 6.2 mean years of life compared with DE. CONCLUSION: In this simulation of 30,000 patients with obesity, CHF, and reduced EF, MBS was associated with improved survival by not only decreasing the need for transplantation due to improvements in EF, but also increasing access to HT when needed due to lower average BMI.

Association of cardiac preservation solution with short-term outcomes after heart transplantation.

AIMS: There is wide variability in the practice of cardiac preservation for heart transplantation. Prior reports suggest that the type of solution may be linked with a reduced incidence of posttransplantation complications. METHODS: Adult (≥18 years old) heart recipients who underwent transplantation between 2015 and 2021 in the United States were examined. Recipients were stratified by solution utilized for their grafts at the time of recovery: University of Wisconsin, histidine-tryptophan-ketoglutarate (HTK), or Celsior solution. The primary endpoint was a composite of 30-day mortality, primary graft dysfunction, or re-transplantation. Risk adjustment was performed for the recipient, donor, and procedural characteristics using regression modeling. RESULTS: Among 16 884 recipients, the group distribution was University of Wisconsin solution 53%, HTK 22%, Celsior solution 15%, and other 10%. The observed incidence of the composite endpoint (University of Wisconsin solution = 3.6%, HTK = 4.0%, Celsior solution = 3.7%, P = 0.301) and 1-year survival (University of Wisconsin solution = 91.7%, HTK = 91.3%, Celsior solution = 91.7%, log-rank P = 0.777) were similar between groups. After adjustment, HTK was associated with a higher risk of the composite endpoint [odds ratio (OR) 1.249, 95% confidence interval (CI) 1.019-1.525, P = 0.030] in reference to University of Wisconsin solution. This association was substantially increased among recipients with ischemic periods of greater than 4 h (OR 1.817, 95% CI 1.188-2.730, P = 0.005). The risks were similar between University of Wisconsin solution and Celsior solution (P = 0.454). CONCLUSION: The use of the histidine-tryptophan-ketoglutarate solution during cold static storage for cardiac preservation is associated with increased rates of early mortality or primary graft dysfunction. Clinician discretion should guide its use, especially when prolonged ischemic times (>4 h) are anticipated.

Kir1.1 and SUR1 are not implicated as subunits of an adenosine triphosphate-sensitive potassium channel involved in diazoxide cardioprotection.

Objective: The adenosine triphosphate-sensitive potassium channel opener diazoxide mimics ischemic preconditioning and is cardioprotective. Clarification of diazoxide's site and mechanism of action could lead to targeted pharmacologic therapies for patients undergoing cardiac surgery. Several mitochondrial candidate proteins have been investigated as potential adenosine triphosphate-sensitive potassium channel components. Renal outer medullary potassium (Kir1.1) and sulfonylurea sensitive regulatory subunit 1 have been suggested as subunits of a mitochondrial adenosine triphosphate-sensitive potassium channel. We hypothesized that pharmacologic blockade or genetic deletion (knockout) of renal outer medullary potassium and sensitive regulatory subunit 1 would result in loss of diazoxide cardioprotection in models of global ischemia with cardioplegia. Methods: Myocyte volume and contractility were compared after Tyrode's physiologic solution (20 minutes), stress (hyperkalemic cardioplegia ± diazoxide, ± VU591 (Kir1.1 inhibitor), N = 9 to 23 each, 20 min), and Tyrode's (20 minutes). Isolated mouse (wild-type, sensitive regulatory subunit 1 [-/-], and cardiac knockout renal outer medullary potassium) hearts were given cardioplegia ± diazoxide (N = 9-16 each) before global ischemia (90 minutes) and 30 minutes reperfusion. Left ventricular pressures were compared before and after ischemia. Results: Stress (cardioplegia) was associated with reduced myocyte contractility that was prevented by diazoxide. Isolated myocytes were not responsive to diazoxide in the presence of VU591. In isolated hearts, diazoxide improved left ventricular function after prolonged ischemia compared with cardioplegia alone in wild-type and knockout (sensitive regulatory subunit 1 [-/-] and cardiac knockout renal outer medullary potassium) mice. Conclusions: Isolated myocyte and heart models may measure independent and separate actions of diazoxide. By definitive genetic deletion, these data indicate that sensitive regulatory subunit 1 and renal outer medullary potassium are not implicated in cardioprotection by diazoxide.

Implementation of a Holistic Review Process of US Allopathic Medical Students Eliminates Non-Comparable Metrics and Bias in General Surgery Residency Interview Invitations.

OBJECTIVE: Use of traditional scoring metrics for residency recruitment creates racial and gender bias. In addition, widespread use of pass/fail grading has led to noncomparable data. To adjust to these challenges, we developed a holistic review (HR) rubric for scoring residency applicants for interview selection. DESIGN: Single-center observational study comparing the proportion of underrepresented in medicine (URM) students and their United States Medical Licensing Exam (USMLE) scores who were invited for interview before (2015-2020) and after (2022) implementation of a holistic review process. SETTING: General surgery residency program at a tertiary academic center. PARTICIPANTS: US allopathic medical students applying for general surgery residency. RESULTS: After initial screening, a total of 1514 allopathic applicants were narrowed down to 586 (38.7%) for HR. A total of 52% were female and 17% identified as URM. Based on HR score, 20% (118/586) of applicants were invited for an interview. The median HR score was 11 (range 4-19). There was a fourfold higher coefficient of variation of HR scores (22.3; 95% CI 21.0-23.7) compared to USMLE scores (5.1; 95% Cl 4.8-5.3), resulting in greater spread and distinction among applicants. There were no significant differences in HR scores between genders (p = 0.60) or URM vs non-URM (p = 0.08). There were no significant differences in Step 1 (p = 0.60) and 2CK (p = 0.30) scores between those who were invited to interview or not. On multivariable analysis, USMLE scores (OR 1.01; 95% CI 0.98-1.03), URM status (OR 1.71 95% CI 0.98-2.92), and gender (OR 0.94, 95% CI 0.60-1.45) did not predict interview selection (all p > 0.05). There was a meaningful increase in the percentage of URM interviewed after HR implementation (12.9% vs 23.1%, p = 0.016). CONCLUSION: The holistic review process is feasible and eliminates the use of noncomparable metrics for surgical applicant interview invitations and increases the percentage of URM applicants invited to interview.

Importance of social vulnerability on long-term outcomes after heart transplantation.

The relationship between social determinants of health and outcomes after heart transplantation has not been examined. The social vulnerability index (SVI) uses United States census data to determine the social vulnerability of every census tract based on 15 factors. This retrospective study seeks to examine the impact of SVI on outcomes after heart transplantation. Adult heart recipients who received a graft between 2012 and 2021 were stratified into SVI percentiles of <75% and SVI of ≥75%. The primary endpoint was survival. The median SVI was 48% (interquartile range: 30%-67%) among 23 700 recipients. One-year survival was similar between groups (91.4 vs 90.7%, log-rank P = .169); however, 5-year survival was lower among individuals living in vulnerable communities (74.8% vs 80.0%, P < .001). This finding persisted despite risk adjustment for other factors associated with mortality (survival time ratio 0.819, 95% confidence interval: 0.755-0.890, P < .001). The incidences of 5-year hospital readmission (81.4% vs 75.4%, P < .001) and graft rejection (40.3% vs 35.7%, P = .004) were higher among individuals living in vulnerable communities. Individuals living in vulnerable communities may be at increased risk of mortality after heart transplantation. These findings suggest there is an opportunity to focus on these recipients undergoing heart transplantation to improve survival.

Variability in Heart Yield From Donation After Brain Death Between Organ Procurement Organizations: An Opportunity for Improvement.

Increasing the number of available hearts for transplantation is the best strategy to decrease waitlist mortality. This study examines organ procurement organizations (OPOs) and their role in the transplantation network to determine whether variability in performance exists across them. Adult deceased donors who met the criteria for brain death between 2010 and 2020 (inclusive) in the United States were examined. A regression model was fitted and internally validated using donor characteristics available at the time of organ recovery to predict the likelihood of heart transplantation. Subsequently, an expected heart yield was calculated for each donor using this model. Observed-to-expected (O/E) heart yield ratios for each OPO were calculated by dividing the number of hearts recovered for transplantation by the expected number of recoveries. There were 58 OPOs active during the study period, and on average, OPO activity grew over time. The mean O/E ratio among OPOs was 0.98 (standard deviation ± 0.18). Twenty-one OPOs consistently performed below the expected level (95% confidence intervals < 1.0) and generated a deficit of 1,088 expected transplantations during the study period. The proportion of hearts that were recovered for transplantation varied significantly by OPO categories: low tier 31.8%, mid tier 35.6%, and high tier 36.2% (p < 0.01), even as the expected yield was similar across tiers (p = 0.69). OPO performance accounts for 28% of the variability in successfully transplanting a heart after accounting for the role of referring hospitals, donor families, and transplantation centers. In conclusion, there is significant variability in volume and heart yield from brain-dead donors across OPOs.

Sounding the Alarm: What Clinicians Need to Know about Physical, Emotional, and Cognitive Recovery After Venoarterial Extracorporeal Membrane Oxygenation.

OBJECTIVE: We summarize the existing data on the occurrence of physical, emotional, and cognitive dysfunction associated with postintensive care syndrome (PICS) in adult survivors of venoarterial extracorporeal membrane oxygenation (VA-ECMO). DATA SOURCES: MEDLINE, Cochrane Library, EMBASE, Web of Science, and CINAHL databases were searched. STUDY SELECTION: Peer-reviewed studies of adults receiving VA-ECMO for any reason with at least one measure of health-related quality of life outcomes or PICS at long-term follow-up of at least 6 months were included. DATA EXTRACTION: The participant demographics and baseline characteristics, in-hospital outcomes, long-term health outcomes, quality of life outcome measures, and prevalence of PICS were extracted. DATA SYNTHESIS: Twenty-seven studies met inclusion criteria encompassing 3,271 patients who were treated with VA-ECMO. The studies were limited to single- or two-center studies. Outcomes variables and follow-up time points evaluated were widely heterogeneous which limits comprehensive analysis of PICS after VA-ECMO. In general, the longer-term PICS-related outcomes of survivors of VA-ECMO were worse than the general population, and approaching that of patients with chronic disease. Available studies identified high rates of abnormal 6-minute walk distance, depression, anxiety, and posttraumatic stress disorder that persisted for years. Half or fewer survivors return to work years after discharge. Only 2 of 27 studies examined cognitive outcomes and no studies evaluated cognitive dysfunction within the first year of recovery. No studies evaluated the impact of targeted interventions on these outcomes. CONCLUSIONS: Survivors of VA-ECMO represent a population of critically ill patients at high risk for deficits in physical, emotional, and cognitive function related to PICS. This systematic review highlights the alarming reality that PICS and in particular, neurocognitive outcomes, in survivors of VA-ECMO are understudied, underrecognized, and thus likely undertreated. These results underscore the imperative that we look beyond survival to focus on understanding the burden of survivorship with the goal of optimizing recovery and outcomes after these life-saving interventions. Future prospective, multicenter, longitudinal studies in recovery after VA-ECMO are justified.

Conditional Survival in Lung Transplantation: An Organ Procurement and Transplantation Network Database Analysis.

Lung transplantation survival estimates are traditionally reported as fixed 1-, 5-, and 10-year mortality rates. Alternatively, this study aims to demonstrate how conditional survival models can provide useful prognostic information tailored to the time a recipient has already survived from the date of transplantation. Recipient data was obtained from the Organ Procurement and Transplantation Network database. Data from 24,820 adult recipients over age 18 who received a lung transplant between 2002 and 2017 were included in the study. Five-year observed conditional survival estimates were calculated by recipient age, sex, race, transplant indication, transplant type ( i.e. , single or double), and renal function at the time of transplantation. Significant variability exists in conditional survival following lung transplantation. Each specific recipient characteristic significantly impacted conditional survival during at least one time point in the first 5 years. Younger age and double lung transplantation were the two most positive predictors of improved conditional survival consistently throughout the 5-year study period. Conditional survival in lung transplantation recipients changes over time and across recipient characteristics. Hazards of mortality are not fixed and need to be dynamically evaluated as a function of time. Conditional survival calculations can provide more accurate prognostic predictions than unconditional survival estimates.

Cardiac Surgeons Highlight the Need for Innovation Stewardship: Noteworthy in 2022.

Modern cardiac surgery has rapidly evolved to treat complex cardiovascular disease. This past year boasted noteworthy advances in xenotransplantation, prosthetic cardiac valves, and endovascular thoracic aortic repair. Newer devices often offer incremental design changes while demanding significant cost increases that leave surgeons to decide if the benefit to patients justifies the increased cost. As innovations are introduced, surgeons must continuously aim to harmonize short- and long-term benefits with financial costs). We must also ensure quality patient outcomes while embracing innovations that will advance equitable cardiovascular care.

Quality and readability of online patient information on the left ventricular assist device.

BACKGROUND: As patients seek online health information to supplement their medical decision-making, the aim of this study is to assess the quality and readability of internet information on the left ventricular assist device (LVAD). METHODS: Three online search engines (Google, Bing, and Yahoo) were searched for "LVAD" and "Left ventricular assist device." Included websites were classified as academic, foundation/advocacy, hospital-affiliated, commercial, or unspecified. The quality of information was assessed using the JAMA benchmark criteria (0-4), DISCERN tool (16-80), and the presence of Health On the Net code (HONcode) accreditation. Readability was assessed using the Flesch Reading Ease score. RESULTS: A total of 38 unique websites were included. The average JAMA and DISCERN scores of all websites were 0.82 ± 1.11 and 52.45 ± 13.51, respectively. Academic sites had a significantly lower JAMA mean score than commercial (p < 0.001) and unspecified (p < 0.001) websites, as well as a significantly lower DISCERN, mean score than commercial sites (p = 0.002). HONcode certification was present in 6 (15%) websites analyzed, which had significantly higher JAMA (p < 0.001) and DISCERN (p < 0.016) mean scores than sites without HONcode certification. Readability was fairly difficult and at the level of high school students. CONCLUSIONS: The quality of online information on the LVAD is variable, and overall readability exceeds the recommended level for the public. Patients accessing online information on the LVAD should be referred to sites with HONcode accreditation. Academic institutions must provide higher quality online patient literature on LVADs.

Heart transplantation outcomes in arrhythmogenic right ventricular cardiomyopathy: a contemporary national analysis.

AIMS: Heart failure is an increasingly recognized later stage manifestation of arrhythmogenic right ventricular cardiomyopathy (ARVC) that can require heart transplantation (HT) to appropriately treat. We aimed to study contemporary ARVC HT outcomes in a national registry. METHODS AND RESULTS: The United Network for Organ Sharing registry was queried for HT recipients from 1/1994 through 2/2020. ARVC patients were compared with non-ARVC dilated, restrictive, and hypertrophic cardiomyopathy HT patients (HT for ischaemic and valvular disease was excluded from analysis). Post-HT survival was assessed using Kaplan-Meier estimates. A total of 189 of 252 (75%) waitlisted ARVC patients (median age 48 years, 65% male) underwent HT, representing 0.3% of the total 65 559 HT during the study time period. Annual frequency of HT for ARVC increased significantly over time. ARVC patients had less diabetes (5% vs. 17%, P < 0.001), less cigarette use (15% vs. 23%, P < 0.001), lower pulmonary artery and pulmonary capillary wedge pressures, and lower cardiac output than the 33 659 non-ARVC patients (P < 0.001). Ventricular assist device use was significantly lower in ARVC patients (8% vs. 32%, P < 0.001); 1 and 5 year post-HT survival was 97% and 93% for ARVC vs. 95% and 82% for non-ARVC HT recipients (P < 0.001). On adjusted multivariable Cox regression, ARVC had decreased risk of post-HT death compared with non-ARVC aetiologies (hazard ratio 0.48, 95% confidence interval 0.28-0.82, P = 0.008). Patients with ARVC also had lower risk of death or graft failure than non-ARVC patients (hazard ratio 0.51, 95% confidence interval 0.32-0.81, P = 0.004). CONCLUSIONS: In the largest series of HT in ARVC, we found that HT is increasingly performed in ARVC, with higher survival compared with other cardiomyopathy aetiologies. The right ventricular predominant pathophysiology may require unique considerations for heart failure management, including HT.

Survival following lung transplantation: A population-based nested case-control study.

BACKGROUND: Lung transplantation is the mainstay of treatment for patients with end-stage respiratory failure. This study sought to evaluate survival following transplantation compared to the general population and quantify standardized mortality ratios (SMRs) using a nested case-control study design. METHODS: Control subjects were nonhospitalized inhabitants of the United States identified through the National Longitudinal Mortality Study. Case subjects were adults who underwent lung transplantation between 1990 and 2007 and identified through the Organ Procurement and Transplantation Network. Propensity-matching (5:1, nearest neighbor, caliper = 0.1) was utilized to identify suitable control subjects based on age, sex, race, and location of residency. The primary study endpoint was 10-year survival. RESULTS: About 14,977 lung transplant recipients were matched to 74,885 nonhospitalized US residents. The 10-year survival rate of lung transplant recipients was 28% (95% confidence interval [CI] = 27%-29%). The population expected mortality rate was 19 deaths/100 person-years while the observed ratio was 104 deaths/100 person-years (SMR = 5.39, 95% CI = 5.35-5.43). The largest discrepancies between observed and expected mortality rates were in females (SMR = 5.97), Hispanic (SMR = 10.70), and single lung recipients (SMR = 5.92). SMRs declined over time (1990-1995 = 5.79, 1996-2000 = 5.64, and 2001-2007 = 5.10). Standardized mortality peaks in the first year after transplant and decreases steadily over time. CONCLUSIONS: Lung transplant recipients experience a fivefold higher SMR compared to the nonhospitalized population. Long-term mortality rates have experienced consistent decline over time.

Appraisal of Donation After Circulatory Death: How Far Could We Expand the Heart Donor Pool?

BACKGROUND: the incidence of organ donation after circulatory death (DCD) is increasing; however, heart use has lagged behind other solid organs. Ex vivo perfusion devices are under United States Food and Drug Administration review for use in DCD heart recovery. This study sought to measure the potential increase in the donor pool if DCD heart donation becomes widely adopted. METHODS: DCD donor data were obtained from Organ Procurement and Transplantation Network database. Selection criteria included donor age 18 to 49 years, donors meeting Maastricht III criteria, warm ischemia time ≤30 minutes, and donation between 2015 and 2020. Exclusion criteria were coronary disease, prior myocardial infarction, ejection fraction <0.50, significant valve disease, bacteremia, pulmonary capillary wedge pressure >15 mm Hg, and history of HIV/hepatitis C virus infections. RESULTS: There were 12 813 DCD donors during this period, of which 3528 met study criteria, and 70 hearts (2%) were transplanted. The use of DCD hearts would represent an additional 48 heart transplants per month, which corresponds to a 21% (3458 of 16 521) increase across the country. Median warm ischemia was 23 minutes, with no difference between hearts that were or were not transplanted (23 vs 22.5 minutes, P = .97). The frequency with which other organs were successfully transplanted was kidney, 92%; liver, 44%; lung, 7%; intestine, 0%; and pancreas, 2%. CONCLUSIONS: Wide adoption of DCD heart transplantation could yield a substantial increase in the donor pool size, with approximately 580 additional organs being available each year across the United States. This would represent the largest increase in the donor pool in the modern era of heart transplantation.

Measuring the effect of the COVID-19 pandemic on solid organ transplantation.

BACKGROUND: The COVID-19 pandemic has uniquely affected the United States. We hypothesize that transplantation would be uniquely affected. METHODS: In this population-based cohort study, adult transplantation data were examined as time series data. Autoregressive-integrated-moving-average models of transplantation rates were developed using data from 1990 to 2019 to forecast the 2020 expected rates in a theoretical scenario if the pandemic did not occur to generate observed-to-expected (O/E) ratios. RESULTS: 32,594 transplants were expected in 2020, and only 30,566 occurred (O/E 0.94, CI 0.88-0.99). 58,152 waitlist registrations were expected and 50,241 occurred (O/E 0.86, CI 0.80-0.94). O/E ratios of transplants were kidney 0.92 (0.86-0.98), liver 0.96 (0.89-1.04), heart 1.05 (0.91-1.23), and lung 0.92 (0.82-1.04). O/E ratios of registrations were kidney 0.84 (0.77-0.93), liver 0.95 (0.86-1.06), heart 0.99 (0.85-1.18), and lung 0.80 (0.70-0.94). CONCLUSIONS: The COVID-19 pandemic was associated with a significant deficit in transplantation. The impact was strongest in kidney transplantation and waitlist registration.

Posttransplant Long-Term Outcomes for Patients with Ventricular Assist Devices on the Heart Transplant Waitlist.

Ventricular assist devices (LVADs) are commonly used in end-stage heart failure for mechanical circulatory support as a bridge to heart transplantation. However, LVADs' long-term effects on posttransplant survival are unknown. We sought to compare long-term mortality after transplantation for patients with and without LVADs. Using the Organ Procurement and Transplantation Network database, we investigated LVADs' impact on long-term (3 month, 1 year, 2 years, 5 years, and 8 years) posttransplant mortality risk for all heart transplant recipients between 2010 and 2019. Time-to-event regression analysis quantified mortality risk by LVAD status in both unconditional and conditional survival analyses. Of 20,113 transplant recipients, 8,999 (45%) had a LVAD while on the waitlist. Among those who died after transplantation, patients with LVADs on average died sooner (1.8 years) than patients without LVADs (3.0 years; p < 0.01). On multivariable analysis, patients with LVADs had a 44% higher mortality risk within the first 3 months posttransplant (HR = 1.44, p = 0.03). There was no significant difference in mortality risk between patients who did and did not have pretransplant LVADs after 1, 2, and 5 years of posttransplant conditional survival. While LVAD patients have a survival disadvantage in the first year posttransplant, conditional survival analysis demonstrated no difference in mortality risk between patients with and without LVADs beyond 1 year of follow up. Of the patients who died posttransplant, patients with LVADs on average died sooner than patients without LVADs.

Diazoxide preserves myocardial function in a swine model of hypothermic cardioplegic arrest and prolonged global ischemia.

OBJECTIVE: Adenosine triphosphate potassium sensitive channels provide endogenous myocardial protection via coupling of cell membrane potential to myocardial metabolism. Adenosine triphosphate potassium sensitive channel openers, such as diazoxide, mimic ischemic preconditioning, prevent cardiomyocyte swelling, preserve myocyte contractility after stress, and provide diastolic protection. We hypothesize that diazoxide combined with hyperkalemic cardioplegia provides superior myocardial protection compared with cardioplegia alone during prolonged global ischemia in a large animal model. METHODS: Twelve pigs were randomized to global ischemia for 2 hours with a single dose of cold blood (4:1) hyperkalemic cardioplegia alone (n = 6) or with diazoxide (500 µmol/L) (n = 6) and reperfused for 1 hour. Cardiac output, myocardial oxygen consumption, left ventricular developed pressure, left ventricular ejection fraction, diastolic function, myocardial troponin, myoglobin, markers of apoptosis, and left ventricular infarct size were compared. RESULTS: Four pigs in the cardioplegia alone group could not be weaned from cardiopulmonary bypass. There were no differences in myoglobin, troponin, or apoptosis between groups. Diazoxide preserved cardiac output versus control (74.5 vs 18.4 mL/kg/min, P = .01). Linear mixed regression modeling demonstrated that the addition of diazoxide to cardioplegia preserved left ventricular developed pressure by 36% (95% confidence interval, 9.9-61.5; P < .01), dP/dt max by 41% (95% confidence interval, 14.5-67.5; P < .01), and dP/dt min by 33% (95% confidence interval, 8.9-57.5; P = .01). It was also associated with higher (but not significant) myocardial oxygen consumption (3.7 vs 1.4 mL O2/min, P = .12). CONCLUSIONS: Diazoxide preserves systolic and diastolic ventricular function in a large animal model of prolonged global myocardial ischemia. Diazoxide as an adjunct to hyperkalemic cardioplegia may allow safer prolonged ischemic times during increasingly complicated cardiac procedures.