PURPOSE: Postoperative thrombotic thrombocytopenic purpura (pTTP) is an uncommon clinical entity in the cardiac surgery patient. If left undiagnosed and untreated, it has a mortality rate as high as 90%. Early recognition and diagnosis of this syndrome may improve the prognosis.
METHODS: A retrospective chart review identified 15 patients of pTTP over the past 24 months at UCI Medical Center. Five of these patients had undergone open heart surgery and form the basis of this study. Type of surgery, time to treatment, hospital course, laboratory analysis, and outcome were recorded.
RESULTS: Heparin-induced thrombocytopenia, disseminated intravascular coagulation, mechanical sources, and less common, drug, infection, and nutritional deficits were investigated, but could not explain the cause of postoperative thrombocytopenia in these five patients (Mean age 67.6). Unexplained thrombocytopenia in the presence of microangiopathic hemolytic anemia as defined by schistocytes on peripheral blood smear, however, was considered sufficient to meet criteria for diagnosis of pTTP. This was accompanied by no symptoms (N=1), limb ischemia (N=1), fever(N=2), neurologic impairment (N=3), and renal failure (N=4). Exchange plasmapheresis was instituted immediately once the diagnosis was established. Mean time to diagnosis was five days. Of the five patients, three had survived.
CONCLUSION: A high suspicion of pTTP should be encouraged when confronted with unexplained thrombocytopenia, which would favor a rapid assessment of the diagnosis. When suspected a blood smear and lab test should be sent immediately, since time will often have elapsed before results have returned. A hematology consult should be obtained and plasmapheresis initiated once the diagnosis is established.
CLINICAL IMPLICATIONS: pTTP following open heart surgery may be more common than previously appreciated, and the syndrome may present with variable intensity. Early diagnosis and treatment with plasmapheresis is the best opportunity to improve prognosis.
DISCLOSURE: Darin Saltzman, None.