Purpose: The purpose of this study was to identify sites of bleeding causing return to the operating room (RTOR) after left ventricular assist device (LVAD) implant and evaluate potential modifiable factors.

National cardiovascular disease (CVD) risk guidelines recommend population-level screening and pharmacotherapy of high CVD risk individuals. A validated CVD surveillance system that provides up-to-date risk factor measurements and treatments across the population is lacking. Crucial evidence gaps exist on the magnitude and distribution of CVD risk and treatments nationally. We evaluated an existing national health analytics system (HAS) as a potential CVD surveillance system. In a single Primary Health Network (PHN), Primary Sense HAS was evaluated as a CVD surveillance system using US Centers for Disease Control guidelines. Any errors found were corrected. Numbers and proportions of patients within different risk groups and on appropriate therapy were reported. Data transfer from general practice electronic medical record systems to to PS were correct, but errors were found regarding Australian CVD guideline implementation. This included incorrect CVD definition, cut-points and terminologies. Following corrections, out of a population of 254,357 individuals, 87,487(34%) were eligible for CVD risk assessment. Of these, 4,199(5%) had pre-existing CVD, 5,124(6%) known high CVD risk and 42,132(54%) had no risk score available. Of those with risk score available, 2,285(6%) were at high risk. In total, 11,608 patients had prior CVD, known high CVD risk or a high-risk score, of whom 6,710(58%) were either untreated or inadequately treated. HAS in current use have the potential to act as surveillance systems to monitor CVD preventive care but only if initially evaluated. This has implications for implementation of future CVD risk guidelines.

Purpose: Our group previously reported the safety and feasibility of the off-pump HeartMate 3 left ventricular assist device in a small cohort of high-risk patients.We now present a larger cohort who underwent offpump HeartMate 3 LVAD placement, the majority via a less invasive approach.The study's primary objective was the safety and feasibility of the off-pump technique compared to the standard on-pump approach with an emphasis on the less invasive technique.Methods: We retrospectively reviewed all patients who underwent Heart-Mate 3 LVAD implantation at our institution since June of 2019.One hundred and sixty-one of these patients underwent on-pump implantation while 52 underwent off-pump implantation with 49 of them (94%) undergoing a less invasive approach which includes bilateral thoracotomies and thoracotomy with hemi-sternotomy.Results: Preoperative characteristics were similar between groups.More patients in the off-pump group were categorized as INTERMACS Profile 1 at the time of implant (67% vs 29% in the on-pump group, p<0.0001).There was no significant difference between total length of stay and in-hospital mortality between the two groups.Postoperative outcomes, including all major complications and short-term survival, were comparable between groups.Conclusion: Results from our single-center, retrospective analysis suggest that off-pump, less invasive LVAD implantation can be offered as a safe alternative for LVAD candidates in critical cardiogenic shock.

Vascularized composite allotransplantation (VCA) has become a valid therapeutic option to restore form and function after devastating tissue loss. However, the need for high-dose multidrug immunosuppression to maintain allograft survival is still hampering more widespread application of VCA. In this study, we investigated the immunoregulatory potential of costimulation blockade (CoB; CTLA4-Ig and anti-CD154 mAb) combined with nonmyeoablative total body irradiation (TBI) to promote allograft survival of VCA in a fully MHC-mismatched mouse model of orthotopic hind limb transplantation. Compared with untreated controls (median survival time [MST] 8 days) and CTLA4-Ig treatment alone (MST 17 days), CoB treatment increased graft survival (MST 82 days), and the addition of nonmyeloablative TBI led to indefinite graft survival (MST > 210 days). Our analysis suggests that VCA-derived BM induced mixed chimerism in animals treated with CoB and TBI + CoB, promoting gradual deletion of alloreactive T cells as the underlying mechanism of long-term allograft survival. Acceptance of donor-matched secondary skin grafts, decreased ex vivo T cell responsiveness, and increased graft-infiltrating Tregs further indicated donor-specific tolerance induced by TBI + CoB. In summary, our data suggest that vascularized BM-containing VCAs are immunologically favorable grafts promoting chimerism induction and long-term allograft survival in the context of CoB.

Background: In femoral access, activated clotting time (ACT) is used to guide sheath removal to reduce bleeding access site complications. Our local radial access protocol mandates immediate sheath removal followed by a standardised compression time irrespective of heparin dosing. We hypothesized that end-of-case ACT was an independent predictor of radial access bleeding complications. Method: We prospectively collected end-of-case ACT for the majority of procedures performed over a 3-month period and documented clinical bleeding events – forearm haematoma graded as per EASY criteria and pseudoaneurysm. Results: Complete data was available for 235 patients, 52% of procedures were performed for acute coronary syndromes and 35% underwent PCI. The mean heparin dose was 5987 units (0–20 000 units) with a mean ACT 169 s (95–393). 8 patients experienced a significant bleeding complication – 6 patients with significant haematoma, 2 pseudoaneurysms. ACT, however, was not a statistically significant predictor of complications (OR 1.006, CI 0.990–1.023, p = 0.46). Discussion: Although the complication rate in radial access remains low, bleeding complications can have a significant impact on post procedural recovery. From our data, ACT did not correlate with bleeding complications. We suggest other factors, such as blood pressure, compression time and compression device technique are associated. A negative aspect of our study is that we did not assess routinely for radial artery occlusion. We are currently performing a larger study to better understand the association between bleeding complications and radial artery access whilst still maintaining a low rate of radial artery occlusion.

Background: Euglycaemic hyperinsulinaemia increases myocardial blood flow reserve (MBFR) and may reduce myocardial ischaemia. Using insulin-dextrose infusions, a two-phase study was conducted to determine: 1) how insulin duration, dose, and diabetes affect MBFR response; 2) the effect of insulin-dextrose on perfusion in the immediate period following revascularisation of ST-elevation myocardial infarction (STEMI).

BACKGROUND:Congenital and acquired chest wall deformities represent a significant challenge to functional reconstruction and may impact feasibility of heart transplantation for patients with end-stage organ failure. In the recent past, the concept of replacing like-with-like tissue by using vascularized composite allografts (VCA) has been enthusiastically employed for reconstruction of complex tissue defects.METHODS:In this study, we introduce a novel murine model for en bloc chest wall, heart, and thymus transplantation and thereby the use of complex tissue allografts for reconstruction of both chest wall defects and also end-stage organ failure. Additionally, this model allows us to study the features of combined vascularized bone marrow (VBM), thymus, and heart transplantation on allograft survival and function. Heterotopic chest wall, thymus, and heart transplants were performed in untreated syngeneic and allogeneic combinations and in allogeneic combinations treated with costimulation blockade (CTLA4-Ig and MR-1).RESULTS:Indefinite (ie, 150 d, N = 3) graft survival was observed in syngeneic controls. In untreated recipients of allogeneic grafts, the skin component was rejected after 10 (±1) days, whereas rejection of the heart occurred after 13 (± 1) days (N = 3). Costimulation blockade treatment prolonged survival of the heart and chest wall component (130 d, N = 3) as well as the VBM niche as evidenced by donor-specific chimerism (average: 2.35 ± 1.44%), whereas interestingly, the skin component was rejected after 13 (±1) days.CONCLUSION:Thus, this novel microsurgical model of VCA combined with solid organ transplantation is technically feasible and results in split tolerance when treated with costimulatory blockade.

Murine full-thickness skin transplantation is a well-established in vivo model to study alloimmune response and graft rejection. Despite its limited application to humans, skin transplantation in mice has been widely employed for transplantation research. The procedure is easy to learn and perform, and it does not require delicate microsurgical techniques nor extensive training. Moreover, graft rejection in this model occurs in a very reproducible immunological reaction and is easily monitored by direct inspection and palpation. In addition, secondary skin transplantation with donor-matched or third-party skin grafts can be performed on more complex transplant models as an alternative and uncomplicated method to assess donor-specific tolerance. The complications are low and are in general limited to anesthesia overdose or respiratory distress after the procedure. Graft failure, on the other hand, occurs commonly as a result of poor preparation of the graft, incorrect positioning in the graft bed, or inappropriate placement of the bandage. In this article, we present a protocol for full-thickness skin transplantation in mice and describe the important steps necessary for a successful procedure.

Abstract Regulatory T cell (Treg) therapy is a promising strategy for extending allograft survival. Treg suppression requires initial T cell receptor (TCR)/peptide-MHC-II (pMHC-II) contacts, the nature of which remains elusive. As inflammation facilitates transfer of pMHC-II from antigen presenting cells (APCs) to activated T cells, we hypothesize that during transplantation associated inflammation, pMHC-II relocate on alloreactive T effector cells and serve as Treg activation signals. To test this, suppression assays were performed using murine CD4+ CD25− (Teff), CD90 depleted APCs, and CD4+ CD25+ Treg cells of different MHC haplotypes. We also used a transplantation model of skin allografts in RAG1 deficient mice injected with Teff and Treg cells from various MHC backgrounds. Data from more than 150 co-culture experiments show that Treg suppression occurs only when Treg and Teff share the same MHC-II, but independently of Treg matching with APC MHC-II. Further experiments demonstrate that pMHC-II complexes, displayed on activated Teff cells, are crucial to the induction of Treg suppression. In vivo results recapitulate the in vitro data: Treg suppression, leading to graft survival, occurs only when Teff and Treg cells are MHC-II matched. Collectively, these findings suggest that suppression of alloreactivity is directed by Treg TCR recognition of pMHC-II complexes exposed on Teff cells. The nature, origin (host vs. donor), and significance of MHC-II loaded peptides have yet to be established. Future studies to improve targeted Treg therapies for transplantation tolerance will focus on mechanisms coupling Treg function with Teff cell activation.

PURPOSE: Developing novel treatment concepts to minimize/avoid immunosuppression by induction of immune tolerance represents the prime task in the field of transplantation. In the clinic to date, this was achieved in highly selected patients in clinical trials of kidney transplantation combined with concomitant stem cell or bone marrow transplantation. Vascularized composite allotransplantation (VCA) is evolving as viable treatment modality for patients suffering from functional and esthetic defects to craniofacial structures, extremities and urogenital tissues. In certain VCAs transplantation of vascularized bone marrow may be inherently part of the allograft designs (i.e. hands and faces) and thereby representing a unique opportunity in combining bone marrow and VCA. METHODS: Murine skin, heart, and hind limb (VCA) transplants were performed across a full MHC mismatch barrier. Recipients treatment comprised non-myeloablative TBI and T-cell depletion and a single dose of post-transplant cyclophosphamide (PTCy). Donor BM and splenocytes (DBM) were injected at the time of transplantation. Post-transplant multi-lineage and, Foxp3 chimerism as well as Vβ-TCR staining was performed. Donor-specific unresponsiveness was tested by MLR and by 2° skin and solid organ transplantation (SOT). Mechanistic studies were undertaken using transgenic mice (DEREG and Foxp3-DTR) to investigate the role of regulatory T cells (Tregs). VCA was performed in animals thymectomized prior to receiving PTCy and the transplant to highlight the role of the thymus in induction and maintenance of tolerance in this murine model. RESULTS: Untreated animals rejected skin grafts, SOT and VCA acutely within 14 ± 1 days, 9 ± 2 days, and 8 ± 1 days, respectively. The treatment regimen extended skin and SOT graft survival (32 ± 8; 65 ± 4, respectively). Additional DBM augmentation lead to allograft survival of >150 days in skin and SOT. However, indefinite graft survival of >150 days was observed in all animals receiving the induction regimen and a VCA ± DBM. In groups receiving a VCA ± DBM, donor chimerism was detected at 22.51% ± 5.96% and 30.17% ± 8.72%, respectively. Prior or post transplantation depletion of recipient-derived Tregs in VCA recipients did not lead to abrogation of tolerance. In recipients of skin graft + DBM, chimerism was not achieved after recipient-derived Treg depletion prior to transplantation (POD-2) and consequently the allografts were rejected (MST = 23.5 days, N=4). In-vitro, Vβ-T cell receptor staining indicates clonal deletion as an additional central tolerance mechanism. However, transplantation into a thymectomized host did not abrogate long-term allograft survival (N=6). All long-term survivors showed donor-specific T cell unresponsiveness in-vitro (MLR) while demonstrated proliferation against 3rd party stimulators. In-vivo, tolerant animals accepted donor-matched secondary skin, while 3rd party FVB/N skin was acutely rejected. Donor-matched hearts were accepted long-term. CONCLUSION: Taken together, robust tolerance and immunosuppression-free long-term allograft survival can be achieved with PTCy in stringent fully MHC mismatched murine models of skin, heart, and vascularized composite allotransplantation. Stable multi lineage chimerism and recipient derived regulatory T cells play a critical role in maintaining tolerance in this model, in particular in the peritransplant time period.

Background Reconstructive transplantation represents a valid therapeutic option after devastating tissue loss such as an extremity or face Immunosuppression-free donor-specific immunological tolera...

In vivo animal model systems, and in particular mouse models, have evolved into powerful and versatile scientific tools indispensable to basic and translational research in the field of transplantation medicine. A vast array of reagents is available exclusively in this setting, including mono- and polyclonal antibodies for both diagnostic and interventional applications. In addition, a vast number of genotyped, inbred, transgenic, and knock out strains allow detailed investigation of the individual contributions of humoral and cellular components to the complex interplay of an immune response and make the mouse the gold standard for immunological research. Vascularized Composite Allotransplantation (VCA) delineates a novel field of transplantation using allografts to replace "like with like" in patients suffering traumatic or congenital tissue loss. This surgical methodological protocol shows the use of a non-suture cuff technique for super-microvascular anastomosis in an orthotopic mouse hind limb transplantation model. The model specifically allows for comparison between established paradigms in solid organ transplantation with a novel form of transplants consisting of various different tissue components. Uniquely, this model allows for the transplantation of a viable vascularized bone marrow compartment and niche that have the potential to exert a beneficial effect on the balance of immune acceptance and rejection. This technique provides a tool to investigate alloantigen recognition and allograft rejection and acceptance, as well as enables the pursuit of functional nerve regeneration studies to further advance this novel field of transplantation.