The Role of Recipient Thyroid Hormone Supplementation in Primary Graft Dysfunction After Heart Transplantation: A Propensity-Adjusted Analysis.

OBJECTIVES: To investigate whether recipient administration of thyroid hormone (liothyronine [T3]) is associated with reduced rates of primary graft dysfunction (PGD) after orthotopic heart transplantation. DESIGN: Retrospective cohort study. SETTING: Single-center, university hospital. PARTICIPANTS: Adult patients undergoing orthotopic heart transplantation. INTERVENTIONS: A total of 609 adult heart transplant recipients were divided into 2 cohorts: patients who did not receive T3 (no T3 group, from 2009 to 2014), and patients who received T3 (T3 group, from 2015 to 2019). Propensity-adjusted logistic regression was performed to assess the association between T3 supplementation and PGD. MEASUREMENTS AND MAIN RESULTS: After applying exclusion criteria and propensity-score analysis, the final cohort included 461 patients. The incidence of PGD was not significantly different between the groups (33.9% no T3 group v 40.8% T3 group; p = 0.32). Mortality at 30 days (3% no T3 group v 2% T3 group; p = 0.53) and 1 year (10% no T3 group v 12% T3 group; p = 0.26) were also not significantly different. When assessing the severity of PGD, there were no differences in the groups' rates of moderate PGD (not requiring mechanical circulatory support other than an intra-aortic balloon pump) or severe PGD (requiring mechanical circulatory support other than an intra-aortic balloon pump). However, segmented time regression analysis revealed that patients in the T3 group were less likely to develop severe PGD. CONCLUSIONS: These findings indicated that recipient single-dose thyroid hormone administration may not protect against the development of PGD, but may attenuate the severity of PGD.

Modeling the effect of patient size on cerebral perfusion during veno-arterial extracorporeal membrane oxygenation.

INTRODUCTION: A well-known complication of veno-arterial extracorporeal membrane oxygenation (VA ECMO) is differential hypoxia, in which poorly-oxygenated blood ejected from the left ventricle mixes with and displaces well-oxygenated blood from the circuit, thereby causing cerebral hypoxia and ischemia. We sought to characterize the impact of patient size and anatomy on cerebral perfusion under a range of different VA ECMO flow conditions. METHODS: We use one-dimensional (1D) flow simulations to investigate mixing zone location and cerebral perfusion across 10 different levels of VA ECMO support in eight semi-idealized patient geometries, for a total of 80 scenarios. Measured outcomes included mixing zone location and cerebral blood flow (CBF). RESULTS: Depending on patient anatomy, we found that a VA ECMO support ranging between 67-97% of a patient's ideal cardiac output was needed to perfuse the brain. In some cases, VA ECMO flows exceeding 90% of the patient's ideal cardiac output are needed for adequate cerebral perfusion. CONCLUSIONS: Individual patient anatomy markedly affects mixing zone location and cerebral perfusion in VA ECMO. Future fluid simulations of VA ECMO physiology should incorporate varied patient sizes and geometries in order to best provide insights toward reducing neurologic injury and improved outcomes in this patient population.

Inhaled Epoprostenol Compared With Nitric Oxide for Right Ventricular Support After Major Cardiac Surgery.

BACKGROUND: Right ventricular failure (RVF) is a leading driver of morbidity and death after major cardiac surgery for advanced heart failure, including orthotopic heart transplantation and left ventricular assist device implantation. Inhaled pulmonary-selective vasodilators, such as inhaled epoprostenol (iEPO) and nitric oxide (iNO), are essential therapeutics for the prevention and medical management of postoperative RVF. However, there is limited evidence from clinical trials to guide agent selection despite the significant cost considerations of iNO therapy. METHODS: In this double-blind trial, participants were stratified by assigned surgery and key preoperative prognostic features, then randomized to continuously receive either iEPO or iNO beginning at the time of separation from cardiopulmonary bypass with the continuation of treatment into the intensive care unit stay. The primary outcome was the composite RVF rate after both operations, defined after transplantation by the initiation of mechanical circulatory support for isolated RVF, and defined after left ventricular assist device implantation by moderate or severe right heart failure according to criteria from the Interagency Registry for Mechanically Assisted Circulatory Support. An equivalence margin of 15 percentage points was prespecified for between-group RVF risk difference. Secondary postoperative outcomes were assessed for treatment differences and included: mechanical ventilation duration; hospital and intensive care unit length of stay during the index hospitalization; acute kidney injury development including renal replacement therapy initiation; and death at 30 days, 90 days, and 1 year after surgery. RESULTS: Of 231 randomized participants who met eligibility at the time of surgery, 120 received iEPO, and 111 received iNO. Primary outcome occurred in 30 participants (25.0%) in the iEPO group and 25 participants (22.5%) in the iNO group, for a risk difference of 2.5 percentage points (two one-sided test 90% CI, -6.6% to 11.6%) in support of equivalence. There were no significant between-group differences for any of the measured postoperative secondary outcomes. CONCLUSIONS: Among patients undergoing major cardiac surgery for advanced heart failure, inhaled pulmonary-selective vasodilator treatment using iEPO was associated with similar risks for RVF development and development of other postoperative secondary outcomes compared with treatment using iNO. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT03081052.

Transplantation Outcomes with Donor Hearts after Circulatory Death.

BACKGROUND: Data showing the efficacy and safety of the transplantation of hearts obtained from donors after circulatory death as compared with hearts obtained from donors after brain death are limited. METHODS: We conducted a randomized, noninferiority trial in which adult candidates for heart transplantation were assigned in a 3:1 ratio to receive a heart after the circulatory death of the donor or a heart from a donor after brain death if that heart was available first (circulatory-death group) or to receive only a heart that had been preserved with the use of traditional cold storage after the brain death of the donor (brain-death group). The primary end point was the risk-adjusted survival at 6 months in the as-treated circulatory-death group as compared with the brain-death group. The primary safety end point was serious adverse events associated with the heart graft at 30 days after transplantation. RESULTS: A total of 180 patients underwent transplantation; 90 (assigned to the circulatory-death group) received a heart donated after circulatory death and 90 (regardless of group assignment) received a heart donated after brain death. A total of 166 transplant recipients were included in the as-treated primary analysis (80 who received a heart from a circulatory-death donor and 86 who received a heart from a brain-death donor). The risk-adjusted 6-month survival in the as-treated population was 94% (95% confidence interval [CI], 88 to 99) among recipients of a heart from a circulatory-death donor, as compared with 90% (95% CI, 84 to 97) among recipients of a heart from a brain-death donor (least-squares mean difference, -3 percentage points; 90% CI, -10 to 3; P<0.001 for noninferiority [margin, 20 percentage points]). There were no substantial between-group differences in the mean per-patient number of serious adverse events associated with the heart graft at 30 days after transplantation. CONCLUSIONS: In this trial, risk-adjusted survival at 6 months after transplantation with a donor heart that had been reanimated and assessed with the use of extracorporeal nonischemic perfusion after circulatory death was not inferior to that after standard-care transplantation with a donor heart that had been preserved with the use of cold storage after brain death. (Funded by TransMedics; ClinicalTrials.gov number, NCT03831048.).

The association with organ procurement techniques and early cardiac transplant outcomes using cardiac MRI.

BACKGROUND: Heart transplantation (HT) has historically been limited by organ availability. Use of donation after circulatory death (DCD) donors addresses this limitation by utilizing previously unused hearts through use of the Organ Care System (OCS). OBJECTIVES: This study aimed to determine the impact of procurement and transportation method on allograft structure and function using early post-transplant cardiac magnetic resonance imaging (MRI). METHODS: Patients who underwent HT at our institution from February 1, 2020, through April 30, 2021 who underwent cardiac MRI imaging <60 days from transplant were included. Recipient and donor characteristics, clinical outcomes, and MRI findings were compared between those who underwent DCD transplantation using the OCS device (DCD-OCS), brain dead donation (DBD) using the OCS device (DBD-OCS), and DBD transported via cold storage (DBD-cold storage) using one-way analysis of variance. RESULTS: A total of 85 patients underwent HT with a cardiac MRI during the study period. Thirty-one (36%) patients received a DCD organ, 16 (19%) received a DBD-OCS organ and 38 (45%) received a DBD-cold storage organ. Rates of primary graft dysfunction (PGD) were significantly higher in DCD transplants (19.5% DCD vs. .0% DBD-OCS and 5.3% DBD-cold storage; p < .050 across three groups), but with no differences in mortality or rejection. There were no differences in cardiac MRI findings between the three transplant types, including presence of gadolinium hyperenhancement after transplant (all p > .050). CONCLUSIONS: We observed no differences in early cardiac MRI findings between patients that received DCD and DBD-OCS heart transplants compared with those receiving DBD-cold storage transplants.

Anesthetic Care of the Pregnant Patient With Cardiovascular Disease: A Scientific Statement From the American Heart Association.

The pregnancy-related mortality rate in the United States is excessively high. The American Heart Association is dedicated to fighting heart disease and recognizes that cardiovascular disease, preexisting or acquired during pregnancy, is the leading cause of maternal mortality in the United States. Comprehensive scientific statements from cardiology and obstetrics experts guide the treatment of cardio-obstetric patients before, during, and after pregnancy. This scientific statement aims to highlight the role of specialized cardio-obstetric anesthesiology care, presenting a systematic approach to the care of these patients from the anesthesiology perspective. The anesthesiologist is a critical part of the pregnancy heart team as the perioperative physician who is trained to prevent or promptly recognize and treat patients with peripartum cardiovascular decompensation. Maternal morbidity is attenuated with expert anesthesiology peripartum care, which includes the management of neuraxial anesthesia, inotrope and vasopressor support, transthoracic echocardiography, optimization of delivery location, and consideration of advanced critical care and mechanical support when needed. Standardizing the anesthesiology approach to patients with high peripartum cardiovascular risk and ensuring that cardio-obstetrics patients have access to the appropriate care team, facilities, and advanced cardiovascular therapies will contribute to improving peripartum morbidity and mortality.

Improved Outcomes in Severe Primary Graft Dysfunction After Heart Transplantation Following Donation After Circulatory Death Compared With Donation After Brain Death.

BACKGROUND: Primary graft dysfunction (PGD), the leading cause of early mortality after heart transplantation, is more common following donation after circulatory death (DCD) than donation after brain death (DBD). We conducted a single-center, retrospective cohort study to compare the incidence, severity and outcomes of patients experiencing PGD after DCD compared to DBD heart transplantation. METHODS AND RESULTS: Medical records were reviewed for all adult heart transplant recipients at our institution between March 2016 and December 2021. PGD was diagnosed within 24 hours after transplant according to modified International Society for Heart and Lung Transplant criteria. A total of 459 patients underwent isolated heart transplantation during the study period, 65 (14%) following DCD and 394 (86%) following DBD. The incidence of moderate or severe PGD in DCD and DBD recipients was 34% and 23%, respectively (P = 0.070). DCD recipients were more likely to experience severe biventricular PGD than DBD recipients (19% vs 7.4%; P = 0.004). Among patients with severe PGD, DCD recipients experienced shorter median (Q1, Q3) duration of post-transplant mechanical circulatory support (6 [4, 7] vs 9 [5, 14] days; P = 0.039), shorter median post-transplant hospital length of stay (17 [15, 29] vs 52 [26, 83] days; P = 0.004), and similar 60-day survival rates (100% [95% CI: 76.8%-100%] vs 80.0% [63.1%-91.6%]; P = 0.17) and overall survival (log-rank; P = 0.078) compared with DBD recipients. CONCLUSIONS: DCD heart transplant recipients were more likely to experience severe, biventricular PGD than DBD recipients. Despite this, DCD recipients with severe PGD spent fewer days on mechanical circulatory support and in the hospital than similar DBD patients. These findings suggest that patterns of graft dysfunction and recovery may differ between donor types, and they support the expansion of the heart-donor pool with DCD.

Trends in cardiovascular medicine: Update on cardiac transplantation.

Advanced heart failure affects more than 250,000 people in the United States alone and is associated with high risk of morbidity and mortality. Cardiac transplantation provides a cure for patients with advanced disease but has historically been limited by donor availability. Recent changes in the allocation system as well as advances in donor selection, procurement and desensitization protocols have served to widen the donor pool and increase the availability of cardiac transplantation for those in need. This review provides an update on recent advances in cardiac transplantation.

Cardiovascular mechanism of donor brain death and heart recipient survival.

BACKGROUND: Heart donation after donor brain death from cardiac arrest despite successful resuscitation may be associated with worse recipient outcomes due to potential graft ischemia or underlying rhythmic/structural defects. However, selected grafts from such donors often have normal cardiac function and anatomy. We investigated whether a cardiovascular mechanism of donor brain death (CV-DBD) was associated with worse recipient outcomes. METHODS: We queried the United Network for Organ Sharing (UNOS) database for first-time, single-organ, adult (age 18+) heart transplant recipients and their associated donors between January 2005 and March 2021. Recipients were stratified by donor status (CV-DBD vs. non-CV-DBD). We performed multivariable Cox proportional hazards modeling to ascertain whether receiving a CV-DBD graft was independently associated with mortality. RESULTS: Of 35,833 included recipients, 2,702 (7.5%) received CV-DBD grafts. The associated donors were significantly more likely to be female, older, and have a history of diabetes, hypertension, and substance use (all p < .001). On unadjusted Kaplan-Meier analysis, CV-DBD recipients had a significantly reduced median survival than non-CV-DBD recipients (12.0 vs. 13.1 years, log-rank p = .04). However, after adjusting for donor/recipient age, recipient comorbidities, annualized center volume, and transplantation era, CV-DBD organ status was not associated with recipient mortality (hazard ratio: 1.05, 95% confidence interval: 0.96-1.13, p = .28). CONCLUSION: In this analysis of over 35,000 heart transplants, CV-DBD status was not associated with adjusted recipient survival. Donor brain death due to cardiac arrest should not be an absolute contraindication to heart donation, although graft function should be carefully assessed before transplantation.

The Future of heart procurement with donation after circulatory death: Current practice and opportunities for advancement.

Heart Donation after Circulatory Death (DCD) has the potential to significantly increase the number of patients benefitting from heart transplantation. However, the expansion of DCD heart transplantation is currently limited by unanswered questions pertaining to best practices in DCD heart procurement. Additionally, significant variability exists within regulatory frameworks, professional guidelines, and published practices of DCD procurement processes. Here we describe the current practice and outstanding questions related to fundamental aspects of DCD heart procurement, including donor selection, premortem donor intervention, ischemic definitions, confirmation of circulatory death, and techniques for heart procurement and preservation. Addressing these key issues through research and consensus recommendations will facilitate the advancement of the field and ultimately expand the opportunity for heart transplantation to a greater number of patients.

Transplanting thoracic COVID-19 positive donors: An institutional protocol and report of the first 14 cases.

We present our institution's protocol for evaluating and transplanting thoracic organs from COVID-19 positive donors and report the outcomes to date. Hearts from donors testing positive for COVID-19 on any test were eligible for transplantation at our institution provided the donor exhibited no evidence of hypercoagulability or COVID-19 induced hyperinflammatory state during terminal hospitalization. Lungs were eligible if the donor first tested PCR positive on nasopharyngeal swab (NPS) for COVID-19 > 20 days prior to procurement and had a negative lower respiratory tract specimen. We performed 14 thoracic transplants in 13 recipients using organs from COVID-19 positive donors. None of the recipients or healthcare members acquired COVID-19. No recipients suffered unexpected acute rejection. Patient survival is 92% to date, with graft survival 93%. The use of hearts from COVID-19 positive donors may be safe and effective. Transplantation of lungs is unresolved but may be cautiously pursued under the restricted circumstances.

Donation After Circulatory Death in Heart Transplantation: History, Outcomes, Clinical Challenges, and Opportunities to Expand the Donor Pool.

Heart transplantation remains the gold-standard therapy for end-stage heart failure; the expected median survival range is 12-13 years. More than 30,000 heart transplants have been performed globally in the past decade alone. With advances in medical and surgical therapies for heart failure, including durable left ventricular assist devices, an increasing number of patients are living with end-stage disease. Last year alone, more than 2500 patients were added to the heart-transplant waitlist in the United States. Despite recent efforts to expand the donor pool, including an increase in transplantation of hepatitis C-positive and extended-criteria donors, supply continues to fall short of demand. Donation after circulatory death (DCD), defined by irreversible cardiopulmonary arrest rather than donor brain death, is widely used in other solid-organ transplants, including kidney and liver, but has not been widely adopted in heart transplantation. However, resurging interest in DCD donation and the introduction of ex vivo perfusion technology has catalyzed recent clinical trials and the development of DCD heart-transplantation programs. Herein, we review the history of DCD heart transplantation, describe the currently used procurement protocols for it and examine clinical challenges and outcomes of such a procedure.

Progression of aortic valve insufficiency during centrifugal versus axial flow left ventricular assist device support.

OBJECTIVES: Long-term left ventricular assist device (LVAD) support can cause accelerated progression of aortic insufficiency (AI). The MOMENTUM trial has led to increased use of the HeartMate 3 (HM3) LVAD, due to greater hemocompatibility. However, the differential effect on the rate of progression of AI during HM3 support versus HeartMate 2 (HM2) has not been extensively studied. This analysis compares the rates of progression to moderate or severe AI (MSAI) comparing a cohort of patients supported with the HM2 versus HM3. METHODS: A retrospective review was performed on all consecutive patients implanted with HM2 or HM3 between May 2005 and June 2020. Follow-up time was limited to the first 6 years after LVAD implantation. Demographics and 4005 echocardiograms were assessed for 536 HM2 and 300 HM3 patients. The primary end point was progression to MSAI. Univariable and multivariable Cox proportional hazard regression and landmark analyses were performed. RESULTS: Progression to MSAI was greater in the HM2 (17%) versus HM3 (9.9%) cohort. On the univariable analysis, the hazard ratio for HM3 was 0.581 (95% confidence interval 0.370-0.909, P = 0.02) whereas on multivariable analysis hazard ratio was 0.624 (95% confidence interval 0.386-1.008, P = 0.0537). Preoperative AI, female sex and body surface area <2 were significantly associated with progression to MSAI. Landmark analysis suggests that LVAD type has the most significant effect on progression to MSAI between 1 and 2 years post-implantation. CONCLUSIONS: Current practice strategies achieved low rates of progression to MSAI. Preoperative AI, female sex and body surface area <2 were the most important predictors of progression to MSAI. Pump type appears to be of secondary importance.

A Porcine Heterotopic Heart Transplantation Protocol for Delivery of Therapeutics to a Cardiac Allograft.

Cardiac transplantation is the gold standard treatment for end-stage heart failure. However, it remains limited by the number of available donor hearts and complications such as primary graft dysfunction and graft rejection. The recent clinical use of an ex vivo perfusion device in cardiac transplantation introduces a unique opportunity for treating cardiac allografts with therapeutic interventions to improve function and avoid deleterious recipient responses. Establishing a translational, large-animal model for therapeutic delivery to the entire allograft is essential for testing novel therapeutic approaches in cardiac transplantation. The porcine, heterotopic heart transplantation model in the intraabdominal position serves as an excellent model for assessing the effects of novel interventions and the immunopathology of graft rejection. This model additionally offers long-term survival for the pig, given that the graft is not required to maintain the recipient's circulation. The aim of this protocol is to provide a reproducible and robust approach for achieving ex vivo delivery of a therapeutic to the entire cardiac allograft prior to transplantation and provide technical details to perform a survival heterotopic transplant of the ex vivo perfused heart.