Previous outcome definitions for iTTP and their limitations in the context of contemporary management
| Outcome . | Definition . | Limitations . |
|---|---|---|
| Clinical response | Sustained platelet count ≥150 × 109/L and LDH <1.5 times ULN. | — |
| Exacerbation | After a clinical response, platelet count decreases to <150 × 109/L, and LDH is increased within 30 d of cessation of TPE. | Does not account for the temporizing effect of anti-VWF therapy on the platelet count, if anti-VWF therapy is discontinued before ADAMTS13 recovery occurs. |
| Clinical remission | Platelet count remains ≥150 × 109/L and LDH <1.5 times ULN for ≥30 d after cessation of TPE. | Does not distinguish clinical remission from ADAMTS13 remission or account for the possibility that a patient may experience clinical remission without ADAMTS13 remission. |
| Does not account for the temporizing effect of anti-VWF therapy on the platelet count if anti-VWF therapy is discontinued before ADAMTS13 recovery has occurred. | ||
| Relapse | After a clinical remission, platelet count decreases to <150 × 109/L. | Does not distinguish clinical relapse from ADAMTS13 relapse or account for the possibility that a patient may experience ADAMTS13 relapse without clinical relapse. |
| Does not account for the temporizing effect of anti-VWF therapy on the platelet count, if anti-VWF therapy is discontinued before ADAMTS13 recovery has occurred. |
| Outcome . | Definition . | Limitations . |
|---|---|---|
| Clinical response | Sustained platelet count ≥150 × 109/L and LDH <1.5 times ULN. | — |
| Exacerbation | After a clinical response, platelet count decreases to <150 × 109/L, and LDH is increased within 30 d of cessation of TPE. | Does not account for the temporizing effect of anti-VWF therapy on the platelet count, if anti-VWF therapy is discontinued before ADAMTS13 recovery occurs. |
| Clinical remission | Platelet count remains ≥150 × 109/L and LDH <1.5 times ULN for ≥30 d after cessation of TPE. | Does not distinguish clinical remission from ADAMTS13 remission or account for the possibility that a patient may experience clinical remission without ADAMTS13 remission. |
| Does not account for the temporizing effect of anti-VWF therapy on the platelet count if anti-VWF therapy is discontinued before ADAMTS13 recovery has occurred. | ||
| Relapse | After a clinical remission, platelet count decreases to <150 × 109/L. | Does not distinguish clinical relapse from ADAMTS13 relapse or account for the possibility that a patient may experience ADAMTS13 relapse without clinical relapse. |
| Does not account for the temporizing effect of anti-VWF therapy on the platelet count, if anti-VWF therapy is discontinued before ADAMTS13 recovery has occurred. |
Previous outcome definitions are from Scully et al.1