Clinical Research Directory

Longitudinal Cohort of Thrombosis and Hemostasis Diseases

This is a multicenter, prospective, longitudinal, observational cohort study to investigate thrombosis and hemostasis diseases in Chinese patients. This study will collect basic information, diagnostic and treatment information, as well as medical expense information of patients from medical records.The incidence and risk factors of thrombosis and hemostasis diseases, the treatment methods, prognosis and medical expenses of these patients in China will be analyzed. The study will use questionnaire to measure the exposure of patients, and prospectively follow-up to collect the prognosis information.

Genotype and Phenotype Correlation in Hereditary Thrombotic Thrombocytopenic Purpura (Upshaw-Schulman Syndrome)

Hereditary thrombotic thrombocytopenic purpura (Upshaw-Schulman syndrome) is a rare disorder characterized by thrombocytopenia as a result of platelet consumption, microangiopathic hemolytic anemia, occlusion of the microvasculature with von Willebrand factor-platelet-thrombic and ischemic end organ damage. The underlying patho-mechanism is a severe congenital ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin type 1 motif, 13) deficiency which is the result of compound heterozygous or homozygous ADAMTS13 gene mutations. Although considered a monogenic disorder the clinical presentation in Upshaw-Schulman syndrome patients varies considerably without an apparent genotype-phenotype correlation. In 2006 we have initiated a registry for patients with Upshaw-Schulman syndrome and their family members to identify possible triggers of acute bouts of TTP, to document individual clinical courses and treatment requirements as well as possible side effects of long standing plasma substitution, e.g. alloantibody formation or viral infections.

Aspirin for Prophylaxis of TTP

Thrombotic thrombocytopenic purpura (TTP) is a rare and life-threatening thrombotic microangiopathy characterized by thrombocytopenia, microangiopathic hemolytic anemia, and microvascular thrombosis causing neurological and renal abnormalities; it is associated with massive depletion of platelets in the microvasculature to form microthrombi1 . Long-term follow-up of patients with congenital TTP (cTTP) revealed frequent strokes and renal injury. Of 217 surviving patients, 62 (29%) had a stroke; the median age was 21 years. iTTP patients also require long-term follow-up. iTTP patients with low ADAMTS13 activity (\<70%) in remission have a 28% risk of stroke. Survival rates of iTTP patients in remission were lower than those of age-, race-, and sex-matched populations. In terms of stable treatment, maintenance therapy is not recommended for patients with iTTP. Previous studies have shown that aspirin may be able to prevent stroke complications in patients with cTTP and iTTP. In addition to its potential efficacy, the risks of aspirin are small and inexpensive. Aspirin is very effective in secondary prevention of stroke 6. However, the therapeutic value of aspirin in TTP has not been studied previously. To improve the prognosis and survival of patients with cTTP and iTTP, we propose to conduct a prospective study to observe the efficacy and safety of aspirin in patients with cTTP and iTTP in remission.