How many days is plasmapheresis typically performed for suspected Thrombotic Thrombocytopenic Purpura (TTP)?

Plasmapheresis Duration for Suspected TTP

For suspected thrombotic thrombocytopenic purpura (TTP), daily plasmapheresis should be performed until platelet count normalizes (>150,000/μL) for 2-3 consecutive days, which typically requires 5-7 sessions over 7-14 days. 1, 2

Initial Management of Suspected TTP

• Plasmapheresis (therapeutic plasma exchange or TPE) should be initiated immediately upon suspicion of TTP, even before ADAMTS13 results are available, especially in patients with MAHA and thrombocytopenia with platelet count <30 × 10^9/L and creatinine <2.0 mg/dL 1
• TPE should be performed daily at 1-1.5 times plasma volume using fresh frozen plasma as replacement fluid 3
• Concurrent immunosuppressive therapy with high-dose glucocorticoids should be administered alongside TPE 1

Duration of Plasmapheresis

• Continue daily TPE until:

  • Platelet count normalizes to >150,000/μL 3, 2
  • Serum lactate dehydrogenase (LDH) approaches normal range 2
  • No evidence of new or progressive ischemic organ injury 1
  • These parameters should remain stable for 2-3 consecutive days 2

• The median number of TPE sessions required is approximately 13 (range: 1-80), with successful treatment typically requiring more sessions (median 15) than unsuccessful treatment (median 3.5) 3

Monitoring and Adjusting Treatment

• ADAMTS13 activity should be monitored to confirm diagnosis and guide treatment duration 1
• For patients with confirmed TTP (ADAMTS13 activity <10%), continue TPE until clinical and laboratory parameters normalize 1
• If platelet count remains refractory despite multiple TPE sessions, consider checking consecutive ADAMTS13 activity and inhibitor levels to guide decision-making 2

Adjunctive Therapies

• Rituximab should be considered alongside TPE and corticosteroids as part of initial therapy to improve outcomes 1
• Caplacizumab (a nanobody that blocks platelet binding to vWF) can reduce time to platelet count normalization and decrease early recurrence risk, though it increases bleeding risk 1, 4
• In the HERCULES trial, caplacizumab was administered with TPE and continued for 30 days after completing daily TPE 4

Special Considerations

• For refractory cases, do not terminate TPE before 4 weeks of treatment 5
• If TTP is suspected in children, it may be reasonable to defer TPE for 24-48 hours until ADAMTS13 results are available due to lower incidence of TTP and higher procedural risks 6
• For patients with lupus nephritis and suspected TTP, the KDIGO guidelines recommend daily plasma exchange for 14 days or until anti-GBM antibodies are undetectable 6

Common Pitfalls

• Delaying initiation of TPE while waiting for ADAMTS13 results can increase mortality; treatment should begin immediately upon clinical suspicion 1
• Premature discontinuation of TPE before achieving stable normalization of platelet count and LDH may lead to early relapse 2
• Failing to monitor for TPE complications, which can include hemodynamic shifts, coagulation disorders, electrolyte imbalances, and line-related bacteremia 6
• Not considering caplacizumab as adjunctive therapy, which has been shown to reduce time to platelet count normalization and decrease risk of early recurrence 4, 1