Clinical Outcomes in Patients with ADAMTS13-Deficient Thrombotic Thrombocytopenic Purpura (TTP) Who Received Platelet Transfusions (PT).

Case reports describe neurological complications, acute renal failure and death in patients with TTP following PT; these observations have led to recommendations to avoid PT. The Oklahoma TTP-HUS Registry enrolled 254 consecutive patients with their first episode of clinically diagnosed TTP from 11-13-1995 (the date of our initial ADAMTS13 measurement) to 12-31-2006 for whom plasma exchange treatment (PEX) was requested; ADAMTS13 activity was measured in 235 (93%) patients immediately before their first PEX; 44 (19%) patients had ADAMTS13 activity <10%. To avoid selection bias, the 19 patients without ADAMTS13 measurements were also included; 9 died before a sample was obtained. We excluded 11 of the 63 patients because of alternative etiologies or subsequent diagnoses (drug-associated TTP-HUS (5), sepsis (4), cancer (1), post-BMT (1)). The initial episodes of 52 patients were analyzed (42 with ADAMTS13 <10%; 10 not measured). 26 (50%) patients received PT; 23 (88%) only before the first PEX. 13 patients had 1 PT; 9 had 2–3, and 4 had 4–14. 17 (65%) patients received PT for an indication such as central venous catheter placement or hemorrhage, 5 (19%) only because of thrombocytopenia, and 4 (15%) had multiple PT for both reasons.

There were no clinically important differences between the groups of patients who did or did not receive PT. 22 of 26 (85%) patients who received PT had no adverse events in <24 hours. Although there was no difference in the overall occurrence of severe neurologic abnormalities, 2 patients who received PT had new neurologic events <24 hours after a PT (stroke, seizure). Patients who received PT had a higher but not significantly different mortality. 7 patients who received PT died; 3 died 9, 12, and 72 hours after PT; autopsies were performed in 2 of these 3 patients documenting systemic microvascular thrombosis; another patient died 6 hours after PT from intrathoracic hemorrhage due to subclavian line placement. The other 3 patients died 14, 18, and 18 days after PT from S. epidermidis sepsis, respiratory failure, and stroke. 3 patients who had not received PT died; 2 died immediately after diagnosis before PEX could begin; autopsies in both documented systemic microvascular thrombosis. 1 patient died of enterococcal sepsis 11 days after diagnosis.

Conclusions:

1. PT are commonly given to patients with TTP, most often before the diagnosis is established and PEX is begun.

2. Although PT may be followed by severe complications or death, the relation of PT to these adverse events is uncertain.

3. It is prudent to avoid PT in patients with TTP; however in patients with overt hemorrhage or who require a high risk invasive procedure, PT may be appropriate supportive care.