Cristina Santoro

Recurrent thrombosis in patients with polycythemia vera and essential thrombocythemia: incidence, risk factors, and effect of treatments

Polycythemia vera and essential thrombocythemia are typically complicated by thrombosis. According to this multicenter study recurrent thrombosis is observed in about one third of patients. Cytoreduction protects against recurrence of thrombosis. The contemporary use of oral anticoagulants or antiplatelet agents further reduce the incidence of re-thrombosis. Background Prior thrombosis is a well-established risk factor for re-thrombosis in polycythemia vera and essential thrombocythemia but scarce data are available on the rate of re-thrombosis and the optimal strategy for prevention of recurrence. Design and Methods We retrospectively estimated the rate of recurrence in a multicenter cohort of 494 patients (poly-cythemia vera/essential thrombocythemia 235/259) with previous arterial (67.6%) or venous thrombosis (31%) or both (1.4%). First thrombosis was cerebrovascular disease in 191 cases, acute coronary syndrome in 106, peripheral arterial thrombosis in 44, and venous thromboembolism in 160. Microcirculatory events were not computed. Results Thrombosis recurred in 166 patients (33.6%), with an incidence of 7.6% patient-years. Sex, diagnosis (polycythemia vera or essential thrombocythemia), and presence of vascular risk factors did not predict recurrence, whereas age >60 years did (multivariable hazard ratio [HR], 1.67; 95% confidence interval [CI] 1.19–2.32). Increased leukocyte count at the time of the first thrombosis was a risk factor for recurrence in patients <60 years old (HR 3.55; 95% CI 1.02–12.25). Cytoreduction halved the risk in the overall cohort (HR 0.53; 95% CI 0.38–0.73) and the combination with antiplatelet agents or oral anticoagulants was more effective than administration of single drugs. Significant prevention of rethrombosis was independently achieved in patients with venous thromboembolism by both oral anticoagulants (HR 0.32; 95% CI 0.15–0.64) and antiplatelet agents (HR 0.42; 95% CI 0.22–0.77), in those with acute coronary syndrome by cytoreduction (HR 0.30; 95% CI 0.13–0.68), and in those with cerebrovascular disease by antiplatelet agents (HR 0.33; 95% CI 0.16–0.66). The overall incidence of major bleeding was 0.9% patient-years and rose to 2.8% in patients receiving both antiplatelet and anti-vitamin K agents. Conclusions In patients with polycythemia vera and essential thrombocythemia, cytoreduction protects against recurrent thrombosis, particularly after acute coronary syndrome. The contemporary use of oral anticoagulants (after venous thromboembolism) or antiplatelet agents (after cerebrovascular disease or venous thromboembolism) further improves the protective effect. Such findings call for prospective studies aimed at investigating whether strategies tailored according to the type of first thrombosis could improve prevention of recurrences.

Effects of secondary prophylaxis started in adolescent and adult haemophiliacs

Summary.  While primary prophylaxis is a well‐established and recommended method of care delivery for children with severe haemophilia, fewer studies have documented the benefits of secondary prophylaxis started in adolescence or adulthood. To evaluate the role of secondary prophylaxis started in adolescent and adult severe haemophiliacs, a retrospective observational cohort study was conducted in 10 Italian Centres that investigated 84 haemophiliacs who had bled frequently and had thus switched from on‐demand to prophylactic treatment during adolescence (n = 30) or adulthood (n = 54). The consumption of clotting factor concentrates, the orthopaedic and radiological scores, quality of life and disease‐related morbidity were compared before and after starting secondary prophylaxis. Prophylaxis reduced the mean annual number of total and joint bleeds (35.8 vs. 4.2 and 32.4 vs. 3.3; P < 0.01) and of days lost from work/school (34.6 vs. 3.0, P < 0.01). A statistically significant reduction in the orthopaedic score was observed during prophylaxis in adolescents, but not in the whole cohort. Patients used more factor concentrates with corresponding higher costs on prophylaxis, but experienced a better quality of life. With respect to on‐demand treatment, higher factor consumption and cost of secondary prophylaxis were balanced by marked clinical benefits and greater well‐being in this cohort of adolescent/adult haemophiliacs.

Comparison of the rates of joint arthroplasty in patients with severe factor VIII and IX deficiency: an index of different clinical severity of the 2 coagulation disorders.

Data from the Italian Hemophilia Centres were collected to perform a retrospective survey of joint arthroplasty in patients with severe hemophilia. Twenty-nine of 49 hemophilia centers reported that 328 of the 347 operations were carried out in 253 patients with severe hemophilia A (HA) and 19 in 15 patients with severe hemophilia B (HB). When results were normalized to the whole Italian hemophilia population (1770 severe HA and 319 severe HB), patients with HA had a 3-fold higher risk of undergoing joint arthroplasty (odds ratio [OR], 3.38; 95% confidence interval [CI], 1.97-5.77; P < .001). These results were confirmed after adjustment for age, HIV, hepatitis C virus (HCV), and inhibitor in a Cox regression model (HR, 2.65; 95% CI, 1.62-4.33; P < .001). The survival analysis of time to joint arthroplasty in the subset of patients with severe HA was not affected by the severity of factor VIII (FVIII) gene mutations. A systematic review of literature articles reporting joint arthroplasties in HA and HB showed that the proportion of HA patients who had undergone arthroplasties was higher than that of HB patients, in agreement with the findings in our Italian cohort. These data suggest that the 2 inherited coagulation disorders have a different severity of clinical phenotype.

Understanding inhibitor development in haemophilia A: towards clinical prediction and prevention strategies

Summary.  Inhibitor development, because of its impact on patients’ morbidity and quality of life, is presently the most serious complication of haemophilia A treatment. The identification of several genetic and non‐genetic risk factors may be used for the stratification of inhibitor risk and the definition of prevention strategies, particularly for patients with a high‐risk genetic profile. The most extensively studied genetic factor is the type of F8 mutation, i.e. large deletions, nonsense mutations and inversions, which are associated with a higher risk of inhibitor development. This is the basis for the increased risk in patients with inhibitor family history; however, concordance family studies showed that factors other than F8 mutations are involved. An emerging role is investigated for polymorphisms of immune‐regulatory genes that may increase (IL‐10 and TNF‐α) or reduce (CTLA‐4) inhibitor risk and whose heterogeneous ethnic distribution may correlate to the higher inhibitor risk in non‐caucasian patients. A role for FVIII haplotypes, particularly in black haemophiliacs, has been recently proposed. Recent studies report an increased inhibitor risk for initial intensive treatments (surgery or severe bleeds requiring high‐dose and/or prolonged treatment, presence of danger signals), whereas regular prophylaxis (absence of danger signals) exerts a protective effect. A clinical score including the type of F8 mutation, family history of inhibitors and intensive treatment has been recently validated for predicting inhibitor risk. Because of the lack of useful data regarding the role of different types of FVIII concentrates, the stratification of risk in patients starting replacement treatment together with the careful evaluation of indications, doses and duration of treatment at first exposures and further efforts for overcoming barriers to early implementation of prophylaxis are encouraged, particularly for patients with a predictable high inhibitor risk.

Increased risk of recurrent thrombosis in patients with essential thrombocythemia carrying the homozygous JAK2 V617F mutation

Evidence suggests that the JAK2 V617F mutation is associated with an increased risk of first thrombosis in patients with essential thrombocythemia (ET). Whether this mutation is also a risk factor for recurrent thrombosis is currently unknown. To investigate the impact of the JAK2 V617F mutation on the risk of recurrent thrombosis in patients with ET, we carried out a multicentre retrospective cohort study. We recruited 143 patients with previous arterial (64.4%) or venous major thrombosis (34.8%) or both (0.8%); 98 of them (68.5%) carried the mutation. Thrombosis recurred in 43 of the patients (30%); overall, after adjustment for sex, age, presence of vascular risk factors, and treatment after the first thrombosis, the presence of the JAK2 mutation did not predict recurrence (multivariable hazard ratio, HR, 0.88, 95% CI 0.46−1.68). Indeed, the individuals homozygous for the JAK2 V617F (allele burden >50%) mutation had an increased risk of recurrence in comparison with wild-type patients (HR 6.15, 95% CI 1.51–24.92). In conclusion, a homozygous JAK2 V617F mutation is an independent risk factor for recurrent thrombosis in patients with ET.

Benefits of prophylaxis versus on-demand treatment in adolescents and adults with severe haemophilia A: the POTTER study

Rigorous evidence is lacking on long-term outcomes of factor VIII (FVIII) prophylaxis initiated in adolescent or adult patients with severe haemophilia A. The prospective, open-label Prophylaxis versus On-demand Therapy Through Economic Report (POTTER) study (ClinicalTrials.gov NCT01159587) compared long-term late secondary prophylaxis (recombinant FVIII-FS 20-30 IU/kg thrice weekly) with on-demand treatment in patients aged 12 to 55 years with severe haemophilia A. The annual number of joint bleeding episodes (primary endpoint), total bleeding episodes, orthopaedic and radiologic (Pettersson) scores, health-related quality of life (HRQoL), pharmacoeconomic impact, and safety were evaluated over a > 5-year period (2004-2010). Fifty-eight patients were enrolled at 11 centres in Italy; 53 (27 prophylaxis, 26 on demand) were evaluated and stratified into 2 age subgroups (12-25 and 26-55 years). Patients receiving prophylaxis experienced a significantly lower number of joint bleeding episodes vs the on-demand group (annualised bleeding rate, 1.97 vs 16.80 and 2.46 vs 16.71 in younger and older patients, respectively; p=0.0043). Results were similar for total bleeding episodes. Prophylaxis was associated with significantly fewer target joints (p< 0.001), better orthopaedic (p=0.0019) and Pettersson (p=0.0177) scores, better HRQoL, and fewer days of everyday activities lost (p< 0.0001) but required significantly higher FVIII product consumption. The POTTER study is the first prospective, controlled trial documenting long-term benefits of late secondary prophylaxis in adolescents and adults with severe haemophilia A. The benefits of reduced bleeding frequency, improved joint status, and HRQoL may offset the higher FVIII consumption and costs.

Thrombotic risk in patients with primary immune thrombocytopenia is only mildly increased and explained by personal and treatment-related risk factors

An increased risk of thrombosis has been reported in primary immune thrombocytopenia (ITP) and with the use of thrombopoietin (TPO) receptor agonists, on the basis of population studies using administrative databases.

Prevalence of allo-immunization anti-HLA and anti-integrin αIIbβ3 in Glanzmann Thromboasthenia patients

Summary.  Platelet transfusions, main therapy of Glanzmann Thromboasthenia (GT), can induce an allo‐immunization against human leucocyte antigen and integrin αIIbβ3. We have investigated in our GT patients the rate of allo‐immunization and of refractoriness to platelet transfusions. From 1975 until December 2005, we have followed 17 GT patients: 14 type 1, 3 variant type; nine females, eight males; median age at diagnosis 9.8 years (range 1–44.5); median age at the time of the study 35.5 years (range 23.6–68.5). In our patients, 121 bleeding episodes occurred (24 severe, 37 moderate, and 60 mild). Ten major and 22 minor surgical procedures have been performed. Two spontaneous deliveries and three caesarian sections with five live births were performed; moreover, one late foetal loss occurred, and one voluntary abortion was performed. Sixteen of 17 patients have been transfused at least once in life with platelets and/or red blood cells (RBC). All transfused patients have been investigated for the presence of anti‐HLA and anti‐integrin αIIbβ3 allo‐antibodies. The positiveness of allo‐antibodies has been demonstrated in 4/16 transfused patients (25%): isolated for anti‐HLA in two; isolated for anti‐integrin αIIbβ3 in one; and combined in one. In spite of the presence of allo‐antibodies, platelet transfusions have always been effective and the haemostasis was not compromised.

Idiopathic thrombocytopenic purpura (ITP) in the elderly: Clinical course in 178 patients

Abstract:  Idiopathic thrombocytopenic purpura (ITP) is often diagnosed in the elderly (age ≥65 yr), where it generally presents as a chronic disease. The objective of the present study was to describe the natural history of ITP in the elderly and to evaluate the risk of bleeding and the possible occurrence of other pathologies. We retrospectively evaluated 178 ITP patients (82 men, 96 women; mean age: 72 yr) diagnosed between 1981 and 1998. Therapy was started at diagnosis or during follow‐up, depending on the platelet count and/or bleeding events. Sixty‐six out of one hundred and seventy‐eight patients (37%) initiated therapy at diagnosis; whereas in 11 of the 112 untreated patients (9.8%) therapy was necessary during the follow‐up. Low‐dose of prednisone was the first‐line treatment in all patients (mean daily dose of 0.43 mg/kg). Forty‐nine (63.6%) of the seventy‐seven treated patients showed a response, 14 of these (28.6%) suffered a relapse. Another pathology occurred in 19 of the 178 patients (10.7%). We conclude that low‐dose prednisone is an appropriate initial treatment for elderly persons. We also stress that an adequate follow‐up is advisable, given that isolated thrombocytopenia could in some cases be the first sign of another underlying pathology.

Leukocytosis is a risk factor for recurrent arterial thrombosis in young patients with polycythemia vera and essential thrombocythemia

There is evidence that leukocytosis is associated with an increased risk of first thrombosis in patients with polycythemia vera (PV) and essential thrombocythemia (ET). Whether it is a risk factor for recurrent thrombosis too is currently unknown. In the frame of a multicenter retrospective cohort study, we recruited 253 patients with PV (n = 133) or ET (n = 120), who were selected on the basis of a first arterial (70%) or venous major thrombosis (27.6%) or both (2.4%), and who were not receiving cytoreduction at the time of thrombosis. The probability of recurrent thrombosis associated with the leukocyte count recorded at the time of the first thrombosis was estimated by a receiver operating characteristic analysis and a multivariable Cox proportional hazards regression model. Thrombosis recurred in 78 patients (30.7%); multivariable analysis showed an independent risk of arterial recurrence (hazard ratio [HR] 2.16, 95% CI 1.12–4.18) in patients with a leukocyte count that was >12.4 × 109/L at the time of the first thrombotic episode. The prognostic role for leukocytosis was age‐related, as it was only significant in patients that were aged <60 years (HR for arterial recurrence 3.35, 95% CI 1.22–9.19). Am. J. Hematol., 2010.