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[Treatment of thrombotic microangiopathies]
P Debourdeau1, C Zammit, B Souleau
1Service de Médecine Interne, Hôpital Percy, Clamart.
Abstract:
Thrombotic thrombocytopenic purpura and hemolytic uremic syndrome appear as the same expression of thrombotic microangiopathy (TMA), which is a single pathological entity affecting small blood vessels leading to hemolytic anemia, circulatory changes with renal (hemolytic uremic syndrome, HUS) or nervous (thrombotic thrombocytopenic purpura, TTP) involvement. Because of his low incidence, prospective randomized clinical trials are difficult to conduct and apart from plasma exchanges (PE) which appear superior to plasma infusions (PI), other therapeutic recommendations are based on retrospective studies or on anecdotal reports with limited number of patients. In the absence of appropriate therapy, mortality rate was initially above 90% in adults with TTP. Plasma infusions and plasma exchanges have dramatically improved prognosis of the disease, since more than 80% of patients respond to therapy with a survival greater than 80 to 90%. Analysis of data of medical literature shows that plasma exchanges can cure 82% of TMA with 15% of refractory TMA and a mortality rate of 14%. In two randomized trials, PE are more effective than PI with a response rate benefit of 25% and an overall survival increase of 15%. Although severe thrombocytopenia is frequently observed, it is important to avoid platelet transfusions. Platelets infusions induce deleterious effects since they add to the severity and the extend of microvascular thrombi formation. Use of glucocorticoids, heparin, antiplatelet therapy, intravenous immunoglobulin and vincristine are associated with variable results and no controlled study supports their use. Splenectomy is still under discussion but could be of interest in case of relapsing thrombotic microangiopathies as an attempt to reduce the rate of TMA recurrence.
Insights
Thrombotic microangiopathy (TMA), encompassing thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS), is effectively treated with plasma exchanges (PE). PE significantly improves patient survival and response rates compared to plasma infusions (PI).
Area of Science:
- Hematology
- Internal Medicine
- Pathology
Background:
- Thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS) are manifestations of thrombotic microangiopathy (TMA).
- TMA affects small blood vessels, causing hemolytic anemia and organ damage (renal or nervous system).
- Low incidence hinders large-scale clinical trials, making evidence-based therapy challenging.
Purpose of the Study:
- To review the therapeutic landscape for thrombotic microangiopathy (TMA).
- To evaluate the efficacy of plasma exchange (PE) versus plasma infusion (PI) in treating TMA.
- To discuss adjunctive therapies and management strategies for TTP and HUS.
Main Methods:
- Systematic review of medical literature, including retrospective studies and anecdotal reports.
- Analysis of data from randomized clinical trials comparing plasma exchange (PE) and plasma infusion (PI).
- Evaluation of outcomes such as response rate, survival, and refractory disease.
Main Results:
- Plasma exchange (PE) is superior to plasma infusion (PI) for TMA, with a 25% response rate benefit and 15% survival increase.
- PE can cure 82% of TMA cases, with a 14% mortality rate and 15% refractory cases.
- Platelet transfusions are contraindicated due to potential exacerbation of microvascular thrombi.
Conclusions:
- Plasma exchange (PE) is the recommended therapy for thrombotic microangiopathy (TMA), significantly improving outcomes.
- Other therapies like glucocorticoids, heparin, and vincristine have variable results and lack strong evidence.
- Splenectomy may be considered for relapsing TMA to reduce recurrence.