Heart transplant offers are less likely to be accepted on weekends, holidays, and conferences.

BACKGROUND: The existence of a "weekend effect" in heart transplantation (HTx) is understudied. The present study sought to determine whether the odds of (HTx) offer acceptance differed for adult and pediatric candidates depending upon the day on which the offer occurred. METHODS: United Network for Organ Sharing data were used to identify all HTx offers to adult (listing age ≥18) and pediatric candidates from 2000-2019. Odds of offer acceptance were studied, comparing weekends, holidays, and conferences (Society of Thoracic Surgeons [STS], American Association for Thoracic Surgery [AATS], International Society for Heart and Lung Transplantation [ISHLT]) to "baseline" (all other days). Multivariable binary logistic regression analyses were performed to determine independent predictors of offer nonacceptance, controlling for the impacts of program transplant volume, region, and candidate characteristics. RESULTS: A total of 323,953 offers occurred - 298,405 to adults and 25,548 to pediatric candidates. Clinically significant differences did not exist in donor or candidate characteristics between baseline or other events. The number of offers per day was stable throughout the year for both adults (p = 0.191) and pediatrics (p = 0.976). In adults, independently lower odds of acceptance existed on weekends (OR 0.88 [95% CI 0.84-0.92]), conferences in aggregate (0.86 [0.77-0.95]), and holidays in aggregate (0.81 [0.72-0.91]). In children, independently lower odds of acceptance were seen on weekends (0.88 [0.79-0.98]), during STS (0.46 [0.25-0.83], and during Christmas (0.32 [0.14-0.76]). CONCLUSIONS: The day on which a HTx offer occurs significantly impacts its likelihood of acceptance. Further work can determine the impacts of human behavior or resource distribution, but knowledge of this phenomenon can inform efforts to ensure ideal organ allocation throughout the year.

The use of extracorporeal membrane oxygenation in severe necrotizing soft tissue infections complicated by septic shock.

Necrotizing soft tissue infections remain a challenging clinical problem. Delays in diagnosis, incomplete débridement of necrotic tissues, and the hemodynamic instability and end-organ failure associated with overwhelming sepsis all contribute to significant mortality. Extracorporeal support is a well-established tool to support profound cardiopulmonary failure. To broaden the indications for use, we present two cases of young adults with necrotizing soft tissue infections who sustained sepsis-induced hemodynamic collapse and required extracorporeal support to facilitate adequate tissue débridement as a bridge to recovery.

Fulminant Neisseria meningitidis: role for extracorporeal membrane oxygenation.

Invasive meningococcal disease is often associated with complications of septic shock and central nervous system dysfunction. Extracorporeal membrane oxygenation is more commonly being used for respiratory failure and sepsis, but neurologic injury and potential coagulopathy are often considered relative contraindications. We report a successful case of complicated Neisseria meningitidis septic shock with disseminated intravascular coagulopathy requiring extracorporeal support.

Long-term mechanical support for complex left ventricular postinfarct pseudoaneurysms.

Left ventricular free wall rupture can be a catastrophic problem. Although small lacerations can be managed with various techniques of primary closure, larger and more complex defects can be difficult to treat. We present and discuss 2 cases of chronic, complex ventricular pseudoaneurysms managed successfully with long-term mechanical support.

Advances in mechanical circulatory support.

PURPOSE OF REVIEW: Mechanical circulatory support is expanding the treatment of advanced heart failure. The number of heart transplantations performed worldwide remains fairly static, and medical therapy alone for end stage heart failure continues to have dismal results. This article presents the authors' opinion as to the current status, challenges, and future course of the field of mechanical circulatory support. RECENT FINDINGS: There is significant disparity between perceived and actuarial survival of a patient with the diagnosis of advanced heart failure. The traditional indications for mechanical circulatory support are becoming less relevant as the application of the therapy broadens. More devices with improved durability are becoming available, and patient selection, management, and outcomes continue to improve. Long-term myocardial recovery is possible in a population of patients with heart failure through the use of mechanical circulatory support combined with evolving pharmacologic therapy, gene therapy, and other forms of tissue regeneration (stem cells, cellular matrix). SUMMARY: Mechanical circulatory support holds great promise in the treatment of advanced heart failure. It is critical to change the perception of both the clinician and the patient toward the prognosis of end stage heart failure. The prospect of achieving long-term myocardial recovery using mechanical support as a platform for other strategies is exciting and requires intensive future investigation.

Aging and transplant arteriosclerosis in absence of alloreactivity and immunosuppressive drugs in a rat aortic model: recipient age's contribution.

BACKGROUND: Almost half of all transplanted vascularized organ grafts will be lost to transplant arteriosclerosis sometime posttransplantation. Organ shortage for primary transplants and retransplants has led to donor-pool expansion to include elderly donors, knowing that aging per se promotes arteriosclerosis. The current understanding that donor age negatively affects organ and/or patient survival outcome is undermined by variables such as the use of immunosuppressive drugs, their toxicity to the graft, degree of donor-recipient histocompatibility, and the resulting chronic rejection. The purpose of this study was to determine whether the donor's age or recipient's age matters the most in transplant arteriosclerosis in the absence of such variables. METHODS: A syngeneic combination was used where young (2-month-old) and old (22-month-old) donor aortas were injured to initiate neointimal thickening, then transplanted into age-mismatched recipients for 14, 60, and 90 days and then assessed for neointimal thickening. Base level injury response due ischemia and surgery was evaluated in age-matched and noninjured aortic grafts, respectively. RESULTS: Young aortas invariably developed thicker neointima when transplanted into old recipients than when transplanted into young ones. Correspondingly, old aortas transplanted in young recipients consistently developed less neointimal thickening than when transplanted into old recipients. CONCLUSIONS: Our findings strongly suggest that the severity of age-related neointima formation is primarily determined by the recipient's age rather than the donor's age. Therefore, in addition to focusing on donor-specific tolerance induction, strategies aiming at increasing the lifespan of vascularized organ grafts also have to take into consideration the recipient's aging milieu.

Intrathymic inoculation of donor bone marrow induces long-term acceptance of lung allografts.

BACKGROUND: We investigated whether intrathymic inoculation of donor bone marrow at the time of transplantation induced long-term acceptance of lung allografts. METHODS: Four- to-six-week-old August Copenhagen Irish (ACI) and Wistar Furth (WF) rats were used as donors and recipients, respectively. After being inoculated intrathymically with either donor-specific (ACI) or third-party (F344) bone marrow (2.0 x 10(7) cells/lobe), the recipient (WF) animal received a left lung transplant from an ACI donor. A short course of tacrolimus (1 mg/kg per day for 5 days) was administered. Animals were sacrificed at timed intervals after transplantation, and rejection was graded on a scale of 0 (none) to 4 (severe). RESULTS: At 28 days, animals receiving donor-specific bone marrow have lower (p < 0.01) median rejection grade (MRG = 0.25; n = 6) than those receiving third-party bone marrow (MRG = 3; n = 6) and controls (no bone marrow; MRG = 2.5; n = 6). Animals receiving intrathymic donor bone marrow accepted lung allografts up to 380 days with minimal rejection (MRG = 2; n = 6). Long-term lung recipients also accepted a challenging donor-specific heart graft (n = 4) for more than 150 days. In mixed lymphocyte reaction assays, T lymphocytes of WF recipients that had received intrathymic bone marrow (from ACI donor) exhibited low response (similar to self antigens) to donor (ACI) cells, but reacted strongly (five times higher) to third-party (F344) cells. CONCLUSIONS: Intrathymic inoculation of donor bone marrow at the time of transplantation along with a short course of tacrolimus induces long-term acceptance of lung allografts in rats. This simple approach of tolerance induction may have clinical application.

Noninvasive assessment of left ventricular assist devices with cardiovascular computed tomography and impact on management.

BACKGROUND: Left ventricular assist devices (LVADs) provide a bridge to recovery or heart transplantation but require serial assessment. Echocardiographic approaches may be limited by device artifact and acoustic window. Cardiovascular computed tomography (CCT) may provide improved non-invasive imaging of LVADs. We evaluated the diagnostic findings and clinical impact of CCT for non-invasive assessment of patients with LVADs. METHODS: CCT examinations performed between 2005 and 2008 in patients with LVADs were identified. Acquisitions were completed on the identical 64-detector-row scanner with intravenous contrast administration. Electrocardiographic gating was used in patients with pulsatile devices, and peripheral pulse gating was used in patients with continuous-flow devices. Comparison was made between CCT results and 30-day outcomes, including echocardiographic and intraoperative findings. RESULTS: We reviewed 32 CCT examinations from 28 patients. Indications included evaluation of low cardiac output symptoms, assessment of cannula position, low flow reading on the LVAD, and surgical planning. CCT identified critical findings in 6 patients, including thrombosis and inlet cannula malposition, all confirmed intraoperatively. CCT missed 1 case of intra-LVAD thrombus. Using intraoperative findings as the gold standard, CCT's sensitivity was 85% and specificity was 100%. Echocardiographic LVAD evaluation did not correlate with findings on CCT (kappa = -0.29, 95% confidence interval, -0.73 to 0.13). CONCLUSIONS: This preliminary observational cohort study indicates that non-invasive imaging using CCT of LVADs is feasible and accurate. CCT warrants consideration in the initial evaluation of symptomatic patients with LVADs.

Placement of long-term implantable ventricular assist devices without the use of cardiopulmonary bypass.

BACKGROUND: Implantation of ventricular assist devices for cardiac support is normally performed using cardiopulmonary bypass. Post-operative complications could be minimized by the placement of these devices without the use of cardiopulmonary bypass. METHODS: We hypothesize that left ventricular assist devices (LVADs), in selected patients, can be implanted safely off-pump. RESULTS: In 25 patients, LVADs were implanted off-pump (mean age 50 years; 64% male, 36% female; average left ventricular ejection fraction 15%). Pre-operatively 68% of patients were on inotropes, 25% had an intra-aortic ballon pump, and 44% had a previous sternotomy. Blood utilization intra- and post-operatively was relatively minimal with 1 re-exploration for bleeding. There were 3 deaths. CONCLUSIONS: We describe a technique for successful placement of a left ventricular assist device without the use of cardiopulmonary bypass.