CABG patient risk for pTTP highlighted
MedWire News: US researchers highlight the importance of early diagnosis of postoperative thrombotic thrombocytopenic purpura (pTTP) in patients after coronary artery bypass graft (CABG) surgery.
Noting that around 20% of patients will not survive pTTP, the team writes in the Annals of Thoracic Surgery: “pTTP should be recognized as a possible pathophysiologic mechanism for unexplained postoperative thrombocytopenia and treatment should be initiated once the diagnosis is established.”
Darin Saltzman (University of California Los Angeles) and co-workers report on the outcome of five patients who developed pTTP after CABG between 2004 and 2008.
The patients experienced persistent thrombocytopenia (platelet count <50,000/m3) and microangiopathic hemolytic anemia, fever, and neurologic and renal dysfunction. Thromboembolic events were reported in one patient.
The patients were treated with plasmapheresis. Two patients died, and although three recovered between 3 and 8 days after treatment, a further patient died on day 53 from postoperative complications.
“When pTTP is suspected, a peripheral blood smear should be sent for evaluation as soon as possible, because time will often have elapsed before results have returned,” Saltzman et al recommend.
“Antibodies may be sent as an adjunct to confirm the diagnosis of pTTP. In addition, lactose dehydrogenase, reticulocytes, and haptoglobin are used to monitor the progression of the disease.”
They conclude: “Fibrinogen levels, fibrin degradation products, factor V and VIII, and D-dimers are useful to rule out other causes of thrombocytopenia, such as disseminated intravascular coagulation.
“Once pTTP is confirmed, plasma exchange should be initiated to avoid the morbidity and mortality associated with this rare postoperative syndrome.”
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By Lynda Williams