Ann Thorac Surg 2006;81:1944-1945
© 2006 The Society of Thoracic Surgeons
Correspondence
Reply
Andreas Böning, MD,
Jochen T. Cremer, MD, PhD
Department of Cardiovascular Surgery, University Hospital Schleswig-Holstein, Arnold-Heller-Str. 7, Kiel, 24105 Germany
(Email: aboening{at}kielheart.uni-kiel.de).
To the Editor:
The interest of Newall and colleagues [1] in our article [2] gives us the opportunity to clarify some points in our article that could be misunderstanding.
The purpose of our article was not only to describe the incidence of heparin-induced thrombocytopenia type II (HIT II), but also to discuss therapeutic strategies in patients suspected of having this disease. We did not find a single patient with HIT II as diagnosed clinically and by one of the available antiheparin-PF4-antibody (PF 4-AB) assays. We know that up to 50% of patients after cardiac surgery may show positive PF 4-AB tests shortly after the procedure [3]. This does not necessarily confirm the diagnosis of HIT II [4] and severely overestimates the incidence of HIT II. Therefore PF4-AB tests in pediatric patients directly after heart surgery did not seem to serve our purpose. We also know that the presence of PF4-AB is time-dependent [5].
Newall and colleagues [1] questioned the timing of our PF 4-AB screening. Our interest was not to conduct a basic analysis about the time course of PF 4-AB. The timing of our testing was aimed at the HIT II risk profile for scheduled redo procedures. In most patients, one or more cardiac catheterizations under heparin preceeded the PF 4-AB testing, the last catheterization taking place within 60 days before surgery as stated for the four PF 4-AB positive patients (see Table 2 in Ref 1). Moreover our main interest was to avoid heparin exposure during cardiac surgery with extracorporeal circulation in this critical group of patients completely.
In conclusion, we do not agree that we have underestimated the incidence of HIT II, because we have not diagnosed the disease clinically in a single pediatric patient after cardiac surgery. We also did not underestimate the incidence of PF 4-AB, because nearly every patient received heparin, mostly for diagnostic purposes (ie, within 60 days before surgery).
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References
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- Newall F, Ignjatovic V, Monagle P. Temporal aspects of anti-heparin-PF4 antibodies in heparin-induced thrombocytopenia (letter) Ann Thorac Surg 2006;81:1944.[Free Full Text]
- Böning A, Morschheuser T, Bläse U, et al. Incidence of heparin-induced thrombocytopenia and therapeutic strategies in pediatric cardiac surgery Ann Thorac Surg 2005;79:62-65.[Abstract/Free Full Text]
- Pouplard C, May MA, Regina S, Maakaroun A, Fusciardi J, Gruel Y. Changes in the platelet count after cardiopulmonary bypass can efficiently predict the development of pathogenic heaprin-dependent antibodies Blood 2002;100:16a-17a.
- Warkentin TE, Greinacher A. Heparin-induced thrombocytopenia and cardiac surgery Ann Thorac Surg 2003;76:638-648.[Abstract/Free Full Text]
- Warkentin TE, Kelton J. Temporal aspects of heparin-induced thrombocytopenia NEJM 2001;344:1286-1292.[Abstract/Free Full Text]
Related Article
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Temporal Aspects of Anti-Heparin-PF4 Antibodies in Heparin-Induced Thrombocytopenia
- Fiona Newall, Vera Ignjatovic, and Paul Monagle
Ann. Thorac. Surg. 2006 81: 1944.
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