NDT Advance Access originally published online on December 29, 2005
Nephrology Dialysis Transplantation 2006 21(4):1060-1065; doi:10.1093/ndt/gfk017
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
© The Author [2005]. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org
Original Articles: Dialysis and Transplantation
Prolonged aPTT after kidney transplantation due to transient lupus anticoagulants
1 Department of Clinical Biochemistry and 2 Department of Nephrology, Odense University Hospital, Odense and 3 Department of Clinical Biochemistry, Centre for Cardiovascular Research, Aalborg Hospital, Aarhus University Hospital, Denmark
Correspondence and offprint requests to: Mads Nybo, Department of Clinical Biochemistry, Odense University Hospital, DK-5000 Odense C, Denmark. Email: mads.nybo{at}ouh.fyns-amt.dk
Background. After kidney transplantation, a renal biopsy may be needed to elucidate the reasons for lack of graft function. If the activated partial thromboplastin time (aPTT) is prolonged, the biopsy will often be postponed, as increased risk of bleeding must be expected. However, aPTT prolongation is not always due to lack of coagulation factors, but can be due to the presence of lupus anticoagulants (LAs). Clinical observations in our department indicated that a large proportion of recently kidney-transplanted patients developed prolonged aPTT values without clinical complications.
Methods. A prospective study of patients receiving a kidney transplant in 2004 was conducted to investigate the frequency and cause of prolongation of the aPTT.
Results. Twenty-seven patients were included in the study; none had prolonged aPTT or LAs before the transplantation. In the post-transplantation period, 19 patients (70.4%) had a significantly prolonged aPTT. Further investigation showed that for all 19 patients, prolongation was due to acquired antibodies: 13 had developed LAs and six had developed unspecific antibodies. The acquired antibodies were transient and did not affect clinical outcome.
Conclusions. This is the first study investigating prolonged aPTT in the post-transplantation period. All patients with prolonged aPTT had acquired transient antibodies, i.e. LA or ‘LA-like’. If a renal biopsy was requested, 70.4% of the transplanted patients would presumably have their biopsy postponed due to prolonged aPTT, but as LAs do not increase the risk of bleeding, such a delay would be unnecessary. Immediate LA investigation is therefore recommended if a recently transplanted patient requiring surgical procedures has a prolonged aPTT.
Keywords: antiphospholipid antibodies; coagulation; kidney transplantation; renal biopsy