Early‐onset and persisting thrombocytopenia in post‐cardiac surgery patients is rarely due to heparin‐induced thrombocytopenia, even when antibody tests are positive

Abstract

thrombocytopenia in post-cardiac surgery patients is rarely due to heparin-induced thrombocytopenia, even when antibody tests are positive. See also Gruel Y, Pouplard C. Post-operative platelet count profile: the most reliable tool for identifying patients with true heparin-induced thrombocypenia after cardiac surgery. This issue, pp 27-9.Summary. Background: The high frequency of thrombocytopenia in post-cardiac surgery patients makes it challenging to diagnose heparin-induced thrombocytopenia (HIT). Two platelet count profiles are reported as indicating possible HIT in these patients: profile 1 describes a platelet count fall that begins between postoperative days 5 and 10, whereas profile 2 denotes early-onset thrombocytopenia that persists beyond day 5. Objectives: Toexaminehowthese platelet count profiles correlate withantibodystatusandHITpost-cardiacsurgery.Methods:We prospectively screened 581 cardiac surgery patients for heparindependent antibodies by platelet factor 4 (PF4)-heparin immunoassay and platelet-activation test, and performed daily platelet counts (until day 10) with 30-day follow-up. Results: All three patients with platelet count profile 1 tested positive for platelet-activating anti-PF4-heparin IgG antibodies [odds ratio (OR) 521.7, 95% confidence interval (CI) 3.9-34 000, P = 0.002], and were judged to have HIT. In contrast, none of 25 patients with early-onset and persisting thrombocytopenia (profile 2) was judged to have HIT, including five patients testing positivefor platelet-activating anti-PF4-heparin IgG antibodies. In these patients, the frequency of heparin-dependent antibodies didnot differfromthat in non-thrombocytopeniccontrols, either for anti-PF4-heparin IgG (OR 1.7, 95% CI 0.7-4.1, P = 0.31) or for platelet-activating antibodies (OR 1.9, 95% CI 0.6-5.7, P = 0.20). Multivariate analysis revealed that type of cardiac surgery, but not HIT antibody status, predicted early-onset and persisting thrombocytopenia. Together, these findings show that HIT was uncommon in this study population [overall frequency, 3/581 (0.5%), 95% CI 0.1-1.5%]. Conclusions: Thrombocytopenia that begins between 5 and 10 days post-cardiac surgery is highly predictive for HIT. In contrast, early-onset and persisting thrombocytopenia is usually caused by non-HIT factors with coinciding heparin-dependent antibody seroconversion.

Thrombocytopenia in the critically ill

“…4 Les numérations plaquettaires sont souvent basses les premiers jours post-chirurgie, le nadir de la numération plaquettaire survenant un à quatre jours après une chirurgie cardiaque et un à deux jours après une chirurgie abdominale ou de greffe du foie. 5,6 La normalisation de la numération plaquettaire survient fréquemment cinq à sept jours après une chirurgie cardiaque ou de greffe du foie et trois à quatre jours après une chirurgie abdominale. 5,6 Une diminution progressive de la numération plaquettaire qui se manifeste plus de cinq à sept jours après l'opération pourrait être le signe d'une coagulopathie de consommation ou d'aplasie médullaire.…”

“…5,6 La normalisation de la numération plaquettaire survient fréquemment cinq à sept jours après une chirurgie cardiaque ou de greffe du foie et trois à quatre jours après une chirurgie abdominale. 5,6 Une diminution progressive de la numération plaquettaire qui se manifeste plus de cinq à sept jours après l'opération pourrait être le signe d'une coagulopathie de consommation ou d'aplasie médullaire. En revanche, une réduction abrupte de la numération plaquettaire qui surviendrait un à deux jours après une augmentation initiale de la numération plaquettaire commençant la deuxième semaine après la chirurgie indiquerait plutôt des causes immunologiques.…”

“…4 Platelet counts are often low for the first few days following surgery, with a platelet count nadir occurring one to four days after cardiac surgery and one to two days after abdominal or liver transplantation surgery. 5,6 Normalization of platelet count often occurs five to seven days following cardiac or liver transplantation surgery and within three to four days after abdominal surgery. 5,6 A gradual decrease in platelet count that develops over five to seven days postoperatively may suggest either consumptive coagulopathy or bone marrow failure.…”

“…5,6 Normalization of platelet count often occurs five to seven days following cardiac or liver transplantation surgery and within three to four days after abdominal surgery. 5,6 A gradual decrease in platelet count that develops over five to seven days postoperatively may suggest either consumptive coagulopathy or bone marrow failure. On the other hand, an abrupt decrease in platelet count, i.e., within one to two days after an initial increase in platelet count that begins in the second week after surgery, is indicative of immunologic causes.…”

The Freedom SOLO bovine pericardial stentless valve

“…27,59 However, no evidence suggests any link to HIT. 61 Platelet activation and aggregation result in diffuse platelet consumption and decreased platelet count, but to date, no FS-associated thromboembolic complications have been reported. Furthermore, no impairment in platelet-fibrinogen interactions for thrombus formation and no change in postoperative platelet function have been observed.…”