Utility of Virtual Crossmatch in Sensitized Patients Awaiting Heart Transplantation

Sensitized candidates for heart transplant usually end up on a long waiting list and have an increased risk of rejection, graft loss, and incidence of cardiac allograft vasculopathy. An increasing number of studies have demonstrated the negative effect of preformed and posttransplant antibodies on graft survival. Thus, in sensitized patients, the combination of new, appropriate, desensitization protocols, and monitoring of posttransplant development of donor-specific antibodies may improve short-term and long-term outcomes. Introduction of more-sensitive and more-specific techniques for antibody detection provides a valid tool for assessing the degree of pretransplant HLA histocompatibility, and, therefore, predicting the results of crossmatch in sensitized patients, which are difficult to transplant. Currently, there are no accurate and standard methods to determine the functional characteristics of antibodies detected by solid-phase assay and, therefore, to predict their clinical relevance. Therefore, the future of heart transplantation requires a better understanding of tissue typing techniques and the effect of anti-HLA antibodies on clinical outcome to prevent discrimination against sensitized patients at the time of organ allocation.

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“…57 In the same study, the authors estimated the positive predictive value of VXM as 79% and its negative value as 92%.…”

Section: Virtual Crossmatchmentioning

confidence: 97%

Current Concepts in Histocompatibility During Heart Transplant

Picascia

Grimaldi²,

Zullo³

et al. 2012

Exp Clin Transplant

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“…The virtual crossmatch is now used by most transplant centers [22••] and has been validated in a number of studies. Stehlik demonstrated a good correlation between the virtual crossmatch and prospective AHG-CDC crossmatch [24]. In a sample of 257 prospective T cell AHG-CDC crossmatches, the virtual crossmatch had a positive predictive value of 79 % and a negative predictive value of 92 %.…”

Section: The Virtual Crossmatchmentioning

confidence: 92%

“…As blood can only be sent out to a limited number of centers at any one time for a prospective crossmatch, the size of the geographic area from which suitable donors can be procured is limited, which significantly increases the wait time to transplantation. The development of the highly sensitive solid-phase antibody assays described above has allowed for identification of potentially cytotoxic recipient antibodies and selection of appropriate donors by use of a "virtual crossmatch" [24]. In this process, cytotoxic antibodies are presumed from the strength of the antibodies determined by single-antigen bead assay and validation tests, as previously described.…”

Section: The Virtual Crossmatchmentioning

confidence: 99%

Approach to the Sensitized Patient Awaiting Heart Transplantation

Patel¹,

Kobashigawa²

2014

Curr Transpl Rep

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The management of the sensitized patient awaiting heart transplant remains a challenge and an active area of research. The development of solid-phase immunoassays (including the C1q assay) has allowed high-resolution determination of antibodies most likely to be associated with antibody-mediated rejection and adverse outcomes. The precision of these techniques has permitted the adoption of the virtual crossmatch, substantially expanding the donor pool for sensitized patients and reducing wait times to transplant. Desensitization strategies continue to evolve, and the most effective therapies appear to be a combined approach utilizing antibody depletion, targeted B cell or plasma cell therapy, or immunomodulation. Further therapy in addition to cytolytic induction may be required at transplant, with judicious monitoring post-transplant for antibody rebound and rejection.

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“…These patients generally do not benefit from left VAD (LVAD) therapy, and generally do not meet Status 1A criteria despite sometimes having significant diastolic dysfunction. Highly sensitized patients may also be at a disadvantage (7), as a result of a smaller compatible donor pool, resulting in increased waitlist time. Patients with a life threatening arrhythmia (8) and congenital heart disease (9) have also been demonstrated to be disadvantaged, due to difficulties qualifying for Status 1A.…”

Section: Introductionmentioning

confidence: 99%

Report From a Forum on US Heart Allocation Policy

Kobashigawa

Johnson

Rogers

et al. 2015

American Journal of Transplantation

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Since the latest revision in US heart allocation policy (2006), the landscape and volume of transplant waitlists have changed considerably. Advances in mechanical circulatory support (MCS) prolong survival, but Status 1A mortality remains high. Several patient subgroups may be disadvantaged by current listing criteria and geographical disparity remains in waitlist time. This forum on US heart allocation policy was organized to discuss these issues and highlight concepts for consideration in the policy development process. A 25-question survey on heart allocation policy was conducted. Among attendees/respondents were 84 participants with clinical/published experience in heart transplant representing 51 US transplant centers, and OPTN/UNOS and SRTR representatives. The survey results and forum discussions demonstrated very strong interest in change to a further-tiered system, accounting for disadvantaged subgroups and lowering use of exceptions. However, a heart allocation score is not yet viable due to the long-term viability of variables (used in the score) in an everdeveloping field. There is strong interest in more refined prioritization of patients with MCS complications, highly sensitized patients and those with severe arrhythmias or restrictive physiology. There is also strong interest in distribution by geographic boundaries modified according to population. Differences of opinion exist between small and large centers.

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Utility of Virtual Crossmatch in Sensitized Patients Awaiting Heart Transplantation

Cited by 80 publications

References 25 publications

Current Concepts in Histocompatibility During Heart Transplant

Current Concepts in Histocompatibility During Heart Transplant

Approach to the Sensitized Patient Awaiting Heart Transplantation

Report From a Forum on US Heart Allocation Policy

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