Timeshare: Intervals vs. points

The purpose of this paper is to explore the different usage options associated with timeshare and why a company would choose to convert their current product form

Postcardiac transplant survival in the current era in patients receiving continuous-flow left ventricular assist devices

ObjectivesContinuous-flow left ventricular assist devices have become the standard of care for patients with heart failure requiring mechanical circulatory support as a bridge to transplant. However, data on long-term post-transplant survival for these patients are limited. We evaluated the effect of continuous-flow left ventricular assist devices on postcardiac transplant survival in the current era.MethodsAll patients who received a continuous-flow left ventricular assist device as a bridge to transplant at a single center from June 2005 to September 2011 were evaluated.ResultsOf the 167 patients who received a continuous-flow left ventricular assist device as a bridge to transplant, 77 (46%) underwent cardiac transplantation, 27 died before transplantation (16%), and 63 (38%) remain listed for transplantation and continued with left ventricular assist device support. The mean age of the transplanted patients was 54.5 ± 11.9 years, 57% had an ischemic etiology, and 20% were women. The overall mean duration of left ventricular assist device support before transplantation was 310 ± 227 days (range, 67-1230 days). The mean duration of left ventricular assist device support did not change in patients who had received a left ventricular assist device in the early period of the study (2005-2008, n = 62) compared with those who had received a left ventricular assist device later (2009-2011, n = 78, 373 vs 392 days, P = NS). In addition, no difference was seen in survival between those patients supported with a left ventricular assist device for fewer than 180 days or longer than 180 days before transplantation (P = NS). The actuarial survival after transplantation at 30 days and 1, 3, and 5 years by Kaplan-Meier analysis was 98.7%, 93.0%, 91.1%, and 88.0%, respectively.ConclusionsThe short- and long-term post-transplant survival for patients bridged with a continuous-flow left ventricular assist device in the current era has been excellent. Furthermore, the duration of left ventricular assist device support did not affect post-transplant survival. The hemodynamic benefits of ventricular unloading with continuous-flow left ventricular assist devices, in addition to their durability and reduced patient morbidity, have contributed to improved post-transplant survival

Heart and lung organ offer acceptance practices of transplant programs are associated with waitlist mortality and organ yield

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145354/1/ajt14885.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145354/2/ajt14885_am.pd

Comparison of Evaluations for Heart Transplant Before Durable Left Ventricular Assist Device and Subsequent Receipt of Transplant at Transplant vs Nontransplant Centers

IMPORTANCE: In 2020, the Centers for Medicare & Medicaid Services revised its national coverage determination, removing the requirement to obtain review from a Medicare-approved heart transplant center to implant a durable left ventricular assist device (LVAD) for bridge-to-transplant (BTT) intent at an LVAD-only center. The association between center-level transplant availability and access to heart transplant, the gold-standard therapy for advanced heart failure (HF), is unknown. OBJECTIVE: To investigate the association of center transplant availability with LVAD implant strategies and subsequent heart transplant following LVAD implant before the Centers for Medicare & Medicaid Services policy change. DESIGN, SETTING, AND PARTICIPANTS: A retrospective cohort study of the Society of Thoracic Surgeons Intermacs multicenter US registry database was conducted from April 1, 2012, to June 30, 2020. The population included patients with HF receiving a primary durable LVAD. EXPOSURES: LVAD center transplant availability (LVAD/transplant vs LVAD only). MAIN OUTCOMES AND MEASURES: The primary outcomes were implant strategy as BTT and subsequent transplant by 2 years. Covariates that might affect listing strategy and outcomes were included (eg, patient demographic characteristics, comorbidities) in multivariable models. Parameters for BTT listing were estimated using logistic regression with center-level random effects and for receipt of a transplant using a Cox proportional hazards regression model with death as a competing event. RESULTS: The sample included 22 221 LVAD recipients with a median age of 59.0 (IQR, 50.0-67.0) years, of whom 17 420 (78.4%) were male and 3156 (14.2%) received implants at LVAD-only centers. Receiving an LVAD at an LVAD/transplant center was associated with a 79% increased adjusted odds of BTT LVAD designation (odds ratio, 1.79; 95% CI, 1.35-2.38; P \u3c .001). The 2-year transplant rate following LVAD implant was 25.6% at LVAD/transplant centers and 11.9% at LVAD-only centers. There was an associated 33% increased rate of transplant at LVAD/transplant centers compared with LVAD-only centers (adjusted hazard ratio, 1.33; 95% CI, 1.17-1.51) with a similar hazard for death at 2 years (adjusted hazard ratio, 0.99; 95% CI, 0.90-1.08). CONCLUSIONS AND RELEVANCE: Receiving an LVAD at an LVAD-transplant center was associated with increased odds of BTT intent at implant and subsequent transplant receipt for patients at 2 years. The findings of this study suggest that Centers for Medicare & Medicaid Services policy change may have the unintended consequence of further increasing inequities in access to transplant among patients at LVAD-only centers

Sensitization in Transplantation: Assessment of Risk (STAR) 2017 Working Group Meeting Report

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/144684/1/ajt14752_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144684/2/ajt14752.pd

Heme Mediated STAT3 Activation in Severe Malaria

The mortality of severe malaria [cerebral malaria (CM), severe malaria anemia (SMA), acute lung injury (ALI) and acute respiratory distress syndrome (ARDS)] remains high despite the availability associated with adequate treatments. Recent studies in our laboratory and others have revealed a hitherto unknown correlation between chemokine CXCL10/CXCR3, Heme/HO-1 and STAT3 and cerebral malaria severity and mortality. Although Heme/HO-1 and CXCL10/CXCR3 interactions are directly involved in the pathogenesis of CM and fatal disease, the mechanism dictating how Heme/HO-1 and CXCL10/CXCR3 are expressed and regulated under these conditions is still unknown. We therefore tested the hypothesis that these factors share common signaling pathways and may be mutually regulated.We first clarified the roles of Heme/HO-1, CXCL10/CXCR3 and STAT3 in CM pathogenesis utilizing a well established experimental cerebral malaria mouse (ECM, P. berghei ANKA) model. Then, we further determined the mechanisms how STAT3 regulates HO-1 and CXCL10 as well as mutual regulation among them in CRL-2581, a murine endothelial cell line.The results demonstrate that (1) STAT3 is activated by P. berghei ANKA (PBA) infection in vivo and Heme in vitro. (2) Heme up-regulates HO-1 and CXCL10 production through STAT3 pathway, and regulates CXCL10 at the transcriptional level in vitro. (3) HO-1 transcription is positively regulated by CXCL10. (4) HO-1 regulates STAT3 signaling.Our data indicate that Heme/HO-1, CXCL10/CXCR3 and STAT3 molecules as well as related signaling pathways play very important roles in the pathogenesis of severe malaria. We conclude that these factors are mutually regulated and provide new opportunities to develop potential novel therapeutic targets that could be used to supplement traditional prophylactics and treatments for malaria and improve clinical outcomes while reducing malaria mortality. Our ultimate goal is to develop novel therapies targeting Heme or CXCL10-related biological signaling molecules associated with development of fatal malaria

Markers of Endothelial Function in Heart Transplant Recipients and Associations with Cardiac Allograft Vasculopathy

University of Minnesota Master of Science thesis. January 2011. Major: Clinical Research. Advisors: Daniel Duprez, Jay Cohn, John Connett. 1 computer file (PDF); viii, 38 pages.Cardiac allograft vasculopathy (CAV) is a major limitation to long-term survival in heart transplant recipients (HTR) accounting for almost 30% of deaths after 5 years. Early non-invasive detection remains a major challenge due the insensitivity and invasiveness of current diagnostic tests. Small vessel disease and endothelial dysfunction are key players in the pathophysiology of CAV. We hypothesize that in HTR there is an impairment of endothelial cellular repair and changes in arterial elasticity, especially in small arteries, resulting in a reduction of small artery elasticity (SAE), an increase in the number of circulating endothelial cells (CEC), and increased CEC activation. In addition, these changes are significant in HTR who develop CAV. Methods: Ninety-seven HTR and 22 normal controls were included in this study. SAE was measured from the radial artery. CEC (CD146+ cells) were enumerated and assessed for activation based on VCAM expression. Continuous variables were analyzed using t-test and dichotomous variables using Chi-square. Logistic regression using stepwise selection was performed to evaluate determinants of CEC, CEC activation, and SAE. Results: The median age was 61years(range, 18-76). The mean duration of transplant was 5.4 ± 5.3 year. 77 % were male and 57% had CAV. HT was associated with significantly lower SAE (p<0.0001) and increased CEC activation (p=0.0004) when compared to healthy controls. We also found that CAV was significantly associated with SAE and CEC (p = 0.04 and 0.01, respectively). On stepwise regression, hypertension treatment and duration of transplant were associated with CAV. Conclusion: Heart transplant is characterized by endothelial activation and dysfunction as evidenced by a reduction in SAE and increased CEC activation. Prospective studies to evaluate these markers as predictors of risk are needed for further evaluation.Colvin, Monica Mechele. (2011). Markers of Endothelial Function in Heart Transplant Recipients and Associations with Cardiac Allograft Vasculopathy. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/104191

Ventriculophasic sinus arrhythmia in the orthotopic transplanted heart: mechanism of disease revisited

Background: Several mechanisms have been proposed for ventriculophasic sinus arrhythmia: phasic changes in baroreceptor mediated vagal input to the sinus node, mechanical effects and pressure changes caused by ventricular systole, and increased blood flow to the sinus node. We attempt to elucidate the role of SA nodal blood flow in the generation of ventriculophasic sinus arrhythmia by measuring phasic changes in PP intervals from the atrial remnants of patients who have received cardiac transplant. Methods: A total of 16 atrial electrogram recordings were obtained from the recipient atrial remnant in 12 patients who had undergone heart transplantation at the University of Miami/Jackson Memorial Hospital. Concomitant recordings of the donor surface ECG were also obtained. Recipient atrial PP intervals that contained a QRS were measured. The QP intervals were also measured and plotted against the associated PP interval to assess the relationship between varying QP intervals and the associated PP interval. Results: A linear relationship between the PP intervals and the associated QP intervals was seen in all patients. Despite widely varying QP intervals, there was little change in the PP intervals suggesting absence of ventriculophasic arrhythmia. Our linear graphs are in contrast to the typical curves seen in ventriculophasic arrhythmia that have been described by Lepeschkin. Conclusions: In our study, there appeared to be absence of ventriculophasic arrhythmia despite intact vagal innervation to the atrial remnant suggesting that the lack of pulsatile SA node blood flow may contribute to the absence of ventriculophasic arrhythmia. We conclude that the transplanted heart, when performed by the standard technique, may provide a model to study mechanisms of ventriculophasic arrhythmia