Publications

Abstract

BACKGROUND: A preservation system, the Organ Care System (OCS; TransMedics) uses normothermic pulsatile perfusion during organ transport for heart transplantation. This system has demonstrated favorable outcomes in hearts recovered from extended-criteria donors after brain death (DBD) and donors after circulatory death (DCD).METHODS: The OCS Heart Perfusion Registry collects data on US heart transplantations using the OCS, static cold storage (SCS), or thoracoabdominal normothermic regional perfusion (NRP) recovered from DBD or DCD donors. We analyzed donor and recipient characteristics and posttransplantation outcomes in patients transplanted with OCS donor hearts (either DBD or DCD) compared with SCS hearts and OCS hearts from DCD donors compared with those recovered with NRP followed by SCS. Propensity score matching was used in survival analyses to adjust for differences among recipient characteristics.RESULTS: Between 2021 and 2023, 3225 consecutive heart transplantations enrolled from 56 centers were analyzed in the Heart Perfusion Registry. The OCS was used in 854 of 3225 heart transplantations (26.4%), among which 340 (39.8%) were DBD and 514 (60.2%) were DCD donors, whereas 2174 DBD donors were recovered with SCS and another 197 DCD donors with NRP techniques. The OCS-DBD group experienced a greater number of organ offer refusals before final acceptance (13 versus 6; Wilcoxon rank sum, P<0.001) and a longer transport distance (667 miles versus 232 miles; Wilcoxon rank sum, P<0.001) compared with SCS-DBD. Survival at 12 months was similar between the 2 groups (89.9% for OCS-DBD versus 90.6% for SCS-DBD; marginal Cox model, P=0.54). Among the OCS-DCD and SCS-DBD groups, survival at 12 months was also similar (91.0% versus 92.5%, respectively; marginal Cox model, P=0.32). The OCS-DCD and NRP-DCD groups demonstrated similar survival (91.0% versus 91.7%, respectively; log rank, P=0.63), although the transport distance was longer in OCS-DCD compared with DCD with NRP followed by SCS (400 miles versus 223 miles; Wilcoxon rank sum, P<0.001). By 2023, 90% of all OCS donor management and recovery was performed with dedicated organ recovery teams.CONCLUSIONS: We demonstrate that real-world implementation of the OCS for DBD donors (using predominantly a dedicated recovery team) is associated with expanded donor criteria, longer transport distance, and excellent posttransplantation outcomes. In OCS-DCD donors, outcomes parallel those of donors recovered with NRP-DCD and compare favorably with DBD donor organs.

View details for DOI 10.1161/CIRCULATIONAHA.124.071743

View details for PubMedID 40052272

Abstract

Current mitral annuloplasty rings fail to restrict the anteroposterior distance while allowing dynamic mitral annular changes. We designed and manufactured a mitral annuloplasty ring that demonstrated axis-specific, selective flexibility to meet this clinical need. The objectives were to evaluate ex vivo biomechanics of this ring and to validate the annular dynamics and safety after ring implantation in vivo.Healthy human mitral annuli (n = 3) were tracked, and motions were isolated. Using the imaging data, we designed and manufactured our axis-specific mitral annuloplasty ring. An ex vivo annular dilation model was used to compare hemodynamics and chordal forces after repair using the axis-specific, rigid, and flexible rings in five porcine mitral valves. In vivo, axis-specific (n = 6), rigid (n = 6), or flexible rings (n = 6) were implanted into male Dorset sheep for annular motion analyses. Five additional animals receiving axis-specific rings survived for up to 6 months.Here we show the axis-specific, rigid, and flexible rings reduced regurgitation fraction to 4.7 ± 2.7%, 2.4 ± 3.2%, and 17.8 ± 10.0%, respectively. The axis-specific ring demonstrated lower average forces compared to the rigid ring (p = 0.046). Five animals receiving axis-specific rings survived for up to 6 months, with mitral annular motion preserved in vivo. Mature neoendocardial tissue coverage over the device was found to be complete with full endothelialization in all animals.The axis-specific mitral annuloplasty ring we designed demonstrates excellent capability to repair mitral regurgitation while facilitating dynamic mitral annular motion. This ring has tremendous potential for clinical translatability, representing a promising surgical solution for mitral regurgitation.

View details for DOI 10.1038/s43856-025-00753-6

View details for PubMedID 39939395

View details for PubMedCentralID 3071018

Abstract

Lipid bilayer nanoparticles (NPs) with and without stromal cell-derived factor (SDF) were created to target and treat ischemia/reperfusion (I/R)-injured myocardium. Male Wistar rats were subjected to myocardial I/R insult and, at reperfusion, randomized to receive systemic injections of 5 mL/kg PBS, 6 μg/kg of NPs, SDF, or SDF-NPs. Four days after treatment, SDF-NPs circulated and accumulated selectively in the ischemic myocardium, with an SDF concentration roughly three times that of the other three treatments. SDF-NP-treated rats had more endothelial progenitor cells (EPCs) in the blood and preserved capillaries and arterioles in the ischemic border myocardium four weeks post-treatment, which improved microvascular perfusion, reduced fibrosis, and preserved heart function. Notably, hearts treated with SDF-NPs retained left ventricular function at four weeks compared to 1-day post-treatment, with a 2.7 ± 1.2 % increase in the ejection fraction. The other three treatments decreased left ventricular function at four weeks (PBS: -7.8 ± 1.2 %, P < 0.001; empty NPs: -3.9 ± 1.3 %, P = 0.004; SDF solution: -5.1 ± 1.3 %, P = 0.001). Hence, systemically injected SDF-NPs selectively accumulate in ischemic cardiac tissue, shielding the myocardium from I/R injury via angiogenic effects through increased EPC migration. This novel cardioprotective drug may be clinically translatable.

View details for DOI 10.1016/j.biomaterials.2025.123167

View details for PubMedID 39947060

View details for DOI 10.1016/j.xjtc.2024.10.021

View details for PubMedID 39991296

View details for PubMedCentralID PMC11845356

View details for DOI 10.1016/j.xjtc.2024.10.021

View details for Web of Science ID 001417013600001

View details for DOI 10.1097/TP.0000000000005320

View details for PubMedID 39789710

Abstract

Cardiovascular diseases remain the leading cause of morbidity and mortality globally, posing significant challenges to public health. The rapid evolution of artificial intelligence (AI), particularly with large language models such as ChatGPT, has introduced transformative possibilities in cardiovascular medicine. This review examines ChatGPT's broad applications in enhancing clinical decision-making-covering symptom analysis, risk assessment, and differential diagnosis; advancing medical education for both healthcare professionals and patients; and supporting research and academic communication. Key challenges associated with ChatGPT, including potential inaccuracies, ethical considerations, data privacy concerns, and inherent biases, are discussed. Future directions emphasize improving training data quality, developing specialized models, refining AI technology, and establishing regulatory frameworks to enhance ChatGPT's clinical utility and mitigate associated risks. As cardiovascular medicine embraces AI, ChatGPT stands out as a powerful tool with substantial potential to improve therapeutic outcomes, elevate care quality, and advance research innovation. Fully understanding and harnessing this potential is essential for the future of cardiovascular health.

View details for DOI 10.3390/jcm13216543

View details for PubMedID 39518681

Abstract

Extracorporeal membrane oxygenation (ECMO) has emerged as a crucial tool in the care of patients with multiorgan failure, and is increasingly utilized as a bridge to transplantation. While data on ECMO as a bridge to isolated heart and lung transplantation have been described, our emerging experience with ECMO as a bridge to thoracic multiorgan transplantation is not yet well understood. This study aims to investigate temporal trends, utilization, and outcomes in ECMO as a bridge to thoracic multiorgan transplantation.The United Network for Organ Sharing database was used to identify adult patients undergoing thoracic multiorgan transplantation between 1987 and 2022. Exclusion criteria were recipient age <18 and bridging with other mechanical circulatory support including ventricular assist device (VAD) and intra-aortic balloon pump (IABP). Survival analysis was performed to compare outcomes between patients bridged to transplantation with ECMO and those who were not bridged.Of 3,927 patients undergoing thoracic multiorgan transplantation, a total of 203 (5.2%) patients received ECMO as a bridge to transplantation. Among ECMO recipients, patients were most commonly bridged to heart-lung (45.8%), followed by heart-kidney (34.5%), and lung-kidney transplantation (11.8%). At a median follow-up of 35.5 months, unadjusted survival among patients bridged with ECMO was decreased versus multiorgan transplant recipients who were not bridged (p<0.001). With adjusted multivariable Cox regression, ECMO was independently associated with an elevated risk of mortality following multiorgan transplantation (HR 1.56 [1.21-2.02], p<0.01). Among patients surviving past 30 days following transplantation, conditional long-term survival was similar between those bridged with ECMO and those not bridged (p = 0.82).ECMO is increasingly utilized as a bridge to thoracic multiorgan transplantation, and is associated with increased 30 day mortality and decreased long-term survival. In select patients surviving to 30 days following transplantation, similar long-term survival is seen between patients bridged with ECMO and those not bridged.

View details for DOI 10.1016/j.healun.2024.09.015

View details for PubMedID 39343333

Abstract

Combined heart-liver transplantation (CHLT) is a definitive therapy reserved for patients with concomitant heart failure and advanced liver disease. A limited number of centers perform CHLT, and even fewer use the en bloc implantation technique. This study 1) reviews clinical outcomes and immunoprotective effects following CHLT, and 2) describes our institution's experience of over two decades using the en bloc technique.All patients who underwent CHLT at our institution between January 2003 and July 2023 were identified. Recipient and donor characteristics, operative details, and clinical outcomes were assessed. Kaplan-Meier analysis was performed to evaluate survival following CHLT.A total of 20 patients underwent CHLT using the en bloc technique at our institution between January 2003 and July 2023. At a median follow-up of 3.8 years for patients who survived the perioperative period (n=18), estimated survival at 1- and 5-years was 94% and 75%, respectively. There was 100% freedom from acute moderate rejection, acute severe rejection, and chronic rejection in all patients. No patients required re-transplantation due to rejection.CHLT is a definitive therapy reserved for patients with multi-organ dysfunction. At our institution, the en bloc technique is the preferred operative approach, as it minimizes cardiac insult, requires fewer anastomoses, minimizes cold ischemia time, and allows for rapid correction of coagulopathy. Overall survival for this cohort is excellent. Episodes of acute rejection were rarely observed, providing further support that the liver may serve an immunoprotective role in multi-organ transplantation.

View details for DOI 10.1016/j.jtcvs.2024.08.031

View details for PubMedID 39187122

Abstract

Ex-vivo normothermic perfusion of cardiac allografts has expanded the donor pool. Utilizing a beating heart implantation method avoids the second cardioplegic arrest and subsequent ischemia reperfusion injury typically associated with ex-vivo heart perfusion. We sought to describe our institutional experience with beating heart transplantation.This was a single-institution retrospective study of adult patients who underwent heart transplantation utilizing ex-vivo heart perfusion (EVHP) and a beating heart implantation technique between October 2022 and March 2024. Primary outcomes of interest included survival, initiation of mechanical circulatory support, and rejection. A sub-analysis of our institutional series of non-beating DCD heart transplantation was also performed.Twenty-four patients underwent isolated heart transplantation with the use of ex-vivo heart perfusion and beating heart implantation between October 2022 and March 2024; 21 (87.5%) received hearts from DCD donors, and 3 (12.5%) patients received hearts from DBD donors. Median follow-up was 192 days (interquartile range of 124-253.5 days), and 23 out of 24 patients (95.8%) were alive at last follow up. No patients required initiation of mechanical circulatory support. The majority of patients had pathological grade 0 rejection at the time of biopsy (n=16, 66.7%), and the median cell-free DNA percent was 0.04% (interquartile range 0.04-0.09). The rate of mechanical circulatory support initiation in the 22-patient non-beating DCD heart transplant cohort was significantly higher at 36.4% (p<0.005).A beating heart implantation technique can be used on DCD and DBD hearts on EVHP and is associated with excellent survival and low levels of rejection.

View details for DOI 10.1016/j.jtcvs.2024.07.058

View details for PubMedID 39111693

Abstract

Pathogenic concepts of right ventricular (RV) failure in pulmonary arterial hypertension focus on a critical loss of microvasculature. However, the methods underpinning prior studies did not take into account the 3-dimensional (3D) aspects of cardiac tissue, making accurate quantification difficult. We applied deep-tissue imaging to the pressure-overloaded RV to uncover the 3D properties of the microvascular network and determine whether deficient microvascular adaptation contributes to RV failure.Heart sections measuring 250-µm-thick were obtained from mice after pulmonary artery banding (PAB) or debanding PAB surgery and properties of the RV microvascular network were assessed using 3D imaging and quantification. Human heart tissues harvested at the time of transplantation from pulmonary arterial hypertension cases were compared with tissues from control cases with normal RV function.Longitudinal 3D assessment of PAB mouse hearts uncovered complex microvascular remodeling characterized by tortuous, shorter, thicker, highly branched vessels, and overall preserved microvascular density. This remodeling process was reversible in debanding PAB mice in which the RV function recovers over time. The remodeled microvasculature tightly wrapped around the hypertrophied cardiomyocytes to maintain a stable contact surface to cardiomyocytes as an adaptation to RV pressure overload, even in end-stage RV failure. However, microvasculature-cardiomyocyte contact was impaired in areas with interstitial fibrosis where cardiomyocytes displayed signs of hypoxia. Similar to PAB animals, microvascular density in the RV was preserved in patients with end-stage pulmonary arterial hypertension, and microvascular architectural changes appeared to vary by etiology, with patients with pulmonary veno-occlusive disease displaying a lack of microvascular complexity with uniformly short segments.3D deep tissue imaging of the failing RV in PAB mice, pulmonary hypertension rats, and patients with pulmonary arterial hypertension reveals complex microvascular changes to preserve the microvascular density and maintain a stable microvascular-cardiomyocyte contact. Our studies provide a novel framework to understand microvascular adaptation in the pressure-overloaded RV that focuses on cell-cell interaction and goes beyond the concept of capillary rarefaction.

View details for DOI 10.1161/CIRCRESAHA.123.323546

View details for PubMedID 38770652

View details for DOI 10.1016/j.athoracsur.2024.03.038

View details for PubMedID 38621652

Abstract

To evaluate the impact of inflammation on anticoagulation monitoring for patients supported with extracorporeal membrane oxygenation (ECMO).Prospective single-center cohort study.University-affiliated tertiary care academic medical center.Adult venovenous and venoarterial ECMO patients anticoagulated with heparin/ MEASUREMENTS AND MAIN RESULTS: C-Reactive protein (CRP) was used as a surrogate for overall inflammation. The relationship between CRP and the partial thromboplastin time (PTT, seconds) was evaluated using a CRP-insensitive PTT assay (PTT-CRP) in addition to measurement using a routine PTT assay. Data from 30 patients anticoagulated with heparin over 371 ECMO days was included. CRP levels (mg/dL) were significantly elevated (median, 17.2; interquartile range [IQR], 9.2-26.1) and 93% of patients had a CRP of ≥5. The median PTT (median 58.9; IQR, 46.9-73.3) was prolonged by 11.3 seconds compared with simultaneously measured PTT-CRP (median, 47.6; IQR, 40.1-55.5; p < 0.001). The difference between PTT and PTT-CRP generally increased with CRP elevation from 2.7 for a CRP of <5.0 to 13.0 for a CRP between 5 and 10, 17.7 for a CRP between 10 and 15, and 15.1 for a CRP of >15 (p < 0.001). In a subgroup of patients, heparin was transitioned to argatroban, and a similar effect was observed (median PTT, 62.1 seconds [IQR, 53.0-78.5 seconds] vs median PTT-CRP, 47.6 seconds [IQR, 41.3-57.7 seconds]; p < 0.001).Elevations in CRP are common during ECMO and can falsely prolong PTT measured by commonly used assays. The discrepancy due to CRP-interference is important clinically given narrow PTT targets and may contribute to hematological complications.

View details for DOI 10.1053/j.jvca.2024.04.006

View details for PubMedID 38960805

View details for Web of Science ID 001281353100300

View details for Web of Science ID 001281353102158

View details for Web of Science ID 001281353101103

View details for Web of Science ID 001281353100231

View details for Web of Science ID 001281353101130

View details for Web of Science ID 001281353101219

View details for Web of Science ID 001281353100193