How we treat thrombotic thrombocytopenic purpura: Results of a Canadian TTP practice survey.

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP) is a rare disease with 90% mortality if untreated. Since the Canadian Apheresis Group (CAG) trial showed greater survival with therapeutic plasma exchange (TPE) versus plasma infusion, there has been widespread adoption of TPE. Beyond TPE, there is significant practice variation. To characterize this, we developed a survey sent to physicians who might be directly involved in TTP management.

METHODS

The survey was sent to CAG members as well as hematologists and nephrologists nationwide and addressed areas of controversy or recognized practice heterogeneity. Descriptive statistics were used to summarize responses, and the χ2 test was used to compare respondents who were and were not CAG physicians. We also compared responses by estimated frequency of TTP cases per year.

RESULTS

The CAG response rate was 31% (13 of 42). The survey was sent to 665 non-CAG physicians, of whom 41 responded (6.1%). Though not statistically different, CAG and non-CAG respondents varied regarding use of corticosteroids, aspirin, and venous thromboembolism (VTE) prophylaxis. Significant differences were found between CAG and non-CAG groups regarding cryosupernatant as fluid choice (69.2% vs. 22.5%, P = .004) and the use of TPE tapering (84.6% vs. 51.3%, P = .034), respectively.

CONCLUSION

TTP treatment is variable across centres in Canada. Areas of significant variation include the choice of replacement fluid for TPE and whether or not and how to taper TPE. Our survey highlights the practice heterogeneity that exists and identifies areas where more evidence is needed and perhaps where trials should be performed.