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NEW YORK (Reuters Health) - Organs from deceased donors who had received AstraZeneca's ChAdOx1 nCoV-19 vaccine against SARS-CoV-2 may possibly prompt vaccine-induced thrombosis and thrombocytopenia (VITT) in recipients, according to a new study.
As a result, the U.K. study team suggests that "liver, lung, pancreas and small bowel transplants from donors with VITT should only proceed in urgent situations."
In a letter in the American Journal of Transplantation, Dr. George Greenhall of the NHS Blood and Transplant, in Bristol, and colleagues note that more than 20 million people in the U.K. have received the ChAdOx1 nCoV-19 vaccine.
VITT may be a complication of such immunization and although the etiology is uncertain, autoantibodies to platelet factor 4 (PF4) may mediate VITT through antibody-dependent platelet activation. Anti-PF4 antibodies are also seen in heparin-induced thrombocytopenia, though most cases of VITT do not have prior heparin exposure.
To examine the possible impact of this emerging syndrome, the researchers identified 13 deceased organ donors who, between January and April of 2021, had presented with thrombosis and/or hemorrhage and laboratory features consistent with VITT. Before admission all had received a first dose of ChAdOx1 nCoV-19 vaccine.
Ultimately only organs from ten donors were used to give 27 allografts (among them 15 kidney and 7 liver transplants) to 26 recipients. After a median follow-up of 19 days, 21 were functioning satisfactorily.
However, two liver recipients and one kidney recipient experienced early allograft failure necessitating explantation. In addition, two transplanted kidneys had impaired allograft function requiring hemodialysis and a presumed cardiac event led to the death of one recipient within a day of transplantation.
During nine days after transplantation there were seven major thrombotic or hemorrhagic complications in six recipients. Two had had their second dose of ChAdOx1 nCoV-19 vaccine within 30 days before transplantation. Neither had features suggestive of VITT at transplantation.
Two of the three patients with bleeding had pre-existing risk factors for hemorrhage. Between three and 22 days after transplantation three liver recipients had detectable anti-PF4 antibodies. One had a thrombotic complication without allograft loss and the other two had uncomplicated post-operative courses. Ten recipients were negative for anti-PF4 antibodies.
Among potential risks of transplantation from donors with VITT, say the researchers are "early major thrombosis or clinically significant bleeding, which may result from pre-existing hemostatic and endothelial dysfunction in the allograft" and "possible transmission of pathogenic lymphocytes producing anti-PF4." However, "The clinical significance of this is unclear; further follow-up will determine whether this portends development of VITT in the recipient."
"In the meantime," the team says, "transplantation of organs from these donors should only proceed after careful consideration of the methods for organ recovery and of the risks and benefits for a potential recipient, and an appropriate consent discussion."
Dr. Greenhall did not respond to requests for comments.
SOURCE: https://bit.ly/3y1Q6Ty American Journal of Transplantation, online July 2, 2021.
As a result, the U.K. study team suggests that "liver, lung, pancreas and small bowel transplants from donors with VITT should only proceed in urgent situations."
In a letter in the American Journal of Transplantation, Dr. George Greenhall of the NHS Blood and Transplant, in Bristol, and colleagues note that more than 20 million people in the U.K. have received the ChAdOx1 nCoV-19 vaccine.
VITT may be a complication of such immunization and although the etiology is uncertain, autoantibodies to platelet factor 4 (PF4) may mediate VITT through antibody-dependent platelet activation. Anti-PF4 antibodies are also seen in heparin-induced thrombocytopenia, though most cases of VITT do not have prior heparin exposure.
To examine the possible impact of this emerging syndrome, the researchers identified 13 deceased organ donors who, between January and April of 2021, had presented with thrombosis and/or hemorrhage and laboratory features consistent with VITT. Before admission all had received a first dose of ChAdOx1 nCoV-19 vaccine.
Ultimately only organs from ten donors were used to give 27 allografts (among them 15 kidney and 7 liver transplants) to 26 recipients. After a median follow-up of 19 days, 21 were functioning satisfactorily.
However, two liver recipients and one kidney recipient experienced early allograft failure necessitating explantation. In addition, two transplanted kidneys had impaired allograft function requiring hemodialysis and a presumed cardiac event led to the death of one recipient within a day of transplantation.
During nine days after transplantation there were seven major thrombotic or hemorrhagic complications in six recipients. Two had had their second dose of ChAdOx1 nCoV-19 vaccine within 30 days before transplantation. Neither had features suggestive of VITT at transplantation.
Two of the three patients with bleeding had pre-existing risk factors for hemorrhage. Between three and 22 days after transplantation three liver recipients had detectable anti-PF4 antibodies. One had a thrombotic complication without allograft loss and the other two had uncomplicated post-operative courses. Ten recipients were negative for anti-PF4 antibodies.
Among potential risks of transplantation from donors with VITT, say the researchers are "early major thrombosis or clinically significant bleeding, which may result from pre-existing hemostatic and endothelial dysfunction in the allograft" and "possible transmission of pathogenic lymphocytes producing anti-PF4." However, "The clinical significance of this is unclear; further follow-up will determine whether this portends development of VITT in the recipient."
"In the meantime," the team says, "transplantation of organs from these donors should only proceed after careful consideration of the methods for organ recovery and of the risks and benefits for a potential recipient, and an appropriate consent discussion."
Dr. Greenhall did not respond to requests for comments.
SOURCE: https://bit.ly/3y1Q6Ty American Journal of Transplantation, online July 2, 2021.
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