Improved survival with plasma exchange in patients with thrombotic thrombocytopenic purpura-hemolytic uremic syndrome. Lara PN Jr, Coe TL, Zhou H, Fernando L, Holland PV, Wun T. The American Journal of Medicine 1999;107(6):573-579.

ABSTRACT:

Thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS) are rare, closely related disorders of unclear etiology that are characterized by microangiopathic hemolytic anemia and thrombocytopenia. These syndromes are generally fatal if left untreated. Plasma exchange (PE) therapy is associated with high response rates and improved short-term survival, but most previous studies have been limited by small numbers of patients or short duration of follow-up. This paper reports on a retrospective cohort analysis of 126 consecutive patients with TTP/HUS, most of whom were treated principally with PE between 1978 and 1998. Of the 126 patients, 95 (75%) had Thrombotic Thrombocytopenic Purpura and the remainder had Hemolytic Uremic Syndrome. About 30% had an underlying serious medical disorder. The overall 30-day mortality was 10% in the 122 patients who received PE as their principal treatment; 56% were complete responders and 21% were partial responders. The relapse rate was 13%. The estimated two-year survival was about 60%; among patients without serious underlying comorbid conditions, the estimated two-year survival was about 80%. Each unit increase in clinical severity score (on a 0 to 8 scale) was associated with a two-fold increase in the odds of 30-day mortality. Patients who were febrile at presentation were substantially less likely to suffer a relapse. In addition, the greater the initial serum creatinine level, the lower the risk of relapse. PE therapy produced high response and survival rates in this large cohort of patients with TTP/HUS. The Clinical Severity Score may be useful in predicting 30-day mortality, whereas fever at onset was associated with a lesser risk of relapse. Prospective studies should stratify patients according to these prognostic factors.