S. M. Siboni

Coagulation factor activity and clinical bleeding severity in rare bleeding disorders: results from the European Network of Rare Bleeding Disorders

Summary.  Background:  The European Network of Rare Bleeding Disorders (EN‐RBD) was established to bridge the gap between knowledge and practise in the care of patients with RBDs.

Rare bleeding disorders

Summary.  Deficiencies of coagulation factors other than factor VIII and factor IX (afibrinogenemia, FII, FV, FV+FVIII, FVII, FX, FXI, FXIII) that cause bleeding disorders (RBDs) are inherited as autosomal recessive traits and are rare, with prevalences in the general population varying between 1 in 500.000 and 1 in 2 million for the homozygous forms. As a consequence of the rarity of these deficiencies, the type and severity of bleeding symptoms, the underlying molecular defects, and the actual management of bleeding episodes are not as well established as for hemophilia A and B. The study of the genetic basis of these disorders could represent an important tool for prevention through prenatal diagnosis. Treatment of patients with RBDs during bleeding episodes or surgery is a challenge because of the lack of experience and the paucity of data. For some deficiency factor concentrates are still non available and severe complications can occur. These complications can be minimized by assessment of risks of bleeding and thrombosis, use of haemostatic means other than blood components or no therapy at all. The RBDs pose a problem for guideline writers because there are no suitable clinical trials to supply good evidence for how these people are best treated. The lack of adequate information on clinical manifestations, treatment and genetic basis of RBDs could be improved by the collection of data in an International Database (http://www.rbdd.org), linkable to others previously published. This could be a useful tool to fill the gap between clinical data and clinical practice. This article reviews the genetic basis of RBDs, problems and complications of treatment, problems in the preparation of suitable guidelines for treatment and the future perspectives of the International Registry on RBDs.

CYP2C9 genotypes and dose requirements during the induction phase of oral anticoagulant therapy

Variant alleles of the CYP2C9 gene encoding the cytochrome P450 (CYP) enzyme (2C9*2 [Arg144Cys] and 2C9*3 [Ile359Leu]) are known to increase the anticoagulant effect of warfarin and decrease the mean daily dose required to maintain the international normalized ratio (INR) of the prothrombin time within the target therapeutic range. However, little information is available on the effect of CYP2C9 polymorphisms on dose requirements during the most critical step of anticoagulant therapy, the induction phase.

Health status and quality of life of elderly persons with severe hemophilia born before the advent of modern replacement therapy

Summary.  Background: More and more people with severe hemophilia reach an old age thanks to an effective treatment. There is no information on the health status and quality of life of elderly people with hemophilia born at a time when replacement therapy was hardly available. Methods: Italian patients with severe hemophilia, aged ≥65 years and hence born in 1942 or earlier, were compared with elderly men without bleeding disorders matched for age, sex, geography and social status. The following aspects were evaluated: concomitant illness, orthopedic status, physical functioning and cognitive status. Measurements of generic and disease‐specific health‐related quality of life were also obtained, together with the presence or absence of depression. Results: Thirty‐nine patients, aged 65–78 years, were investigated; 33 had hemophilia A. All patients had started regular treatment on demand only when they were already 25–30 years of age. Patients were compared with 43 men without hemophilia, aged 65–79 years. More patients with hemophilia had chronic hepatitis B and C, HIV infection and hypertension. On the other hand, their elderly peers without hemophilia were more frequently hypercholesterolemic and had more cardiovascular diseases. Most hemophiliacs had arthropathy and worse values for physical functioning, but their cognitive status was similar to that of elderly non‐hemophiliacs. Hemophiliacs reported greater depression and lower health‐related quality of life. Conclusions: Elderly patients with hemophilia have more co‐morbidities and problems in daily living, but similar cognitive status as age‐matched non‐hemophilic peers. They have more chronic viral infections and hypertension but fewer cardiovascular diseases. These observations should help to optimize health care delivery in this increasing and neglected population of people with hemophilia.

Rotational thromboelastography for monitoring of fibrinogen concentrate therapy in fibrinogen deficiency.

To characterize a functional assay for circulating fibrinogen based on rotational thrombelastography. Maximum clot firmness was determined by rotational thrombelastography in normal human plasma pool, fibrinogen-deficient plasma pool, normal whole blood, and individual plasma samples from 17 patients with fibrinogen deficiency. Plasma samples spiked with varying concentrations of exogenous fibrinogen were also measured. Results were compared with enzyme-linked immunosorbent assay and Clauss assay. The impact of sample freezing and filtration and use of cytochalasin D were also investigated. Over the tested range of 0–3 mg/ml added exogenous fibrinogen, the maximum clot firmness standard curve for determination of fibrinogen in plasma pools (n = 7) was linear (r2 = 0.97). Maximum clot firmness was highly linearly correlated both with Clauss assay (r2 = 0.93) and enzyme-linked immunosorbent assay (r2 = 0.95). In unspiked plasma samples from individual patients with fibrinogen deficiency, fibrinogen was undetectable by rotational thromboelastography. By all evaluated methods, the response to spiking with fibrinogen in such samples coincided closely in patients with afibrinogenemia and hypofibrinogenemia. In dysfibrinogenemia, smaller Clauss assay responses to spiking were observed, whereas the enzyme-linked immunosorbent assay response was variable. Maximum clot firmness was the only evaluated method of fibrinogen assessment to yield consistent results across all categories of fibrinogen deficiency. These in-vitro results suggest the potential clinical utility of rotational thromboelastography as a versatile method for monitoring the response to fibrinogen concentrate among patients with fibrinogen deficiency. Clinical investigations using rotational thromboelastography after in-vivo fibrinogen administration to patients with congenital fibrinogen deficiency are warranted.

Prospective study on the behaviour of the metalloprotease ADAMTS13 and of von Willebrand factor after bone marrow transplantation

Thrombotic microangiopathies (TMAs) are rare but serious complications of bone marrow transplantation (BMT). Clinical manifestations are similar to those of thrombotic thrombocytopenic purpura (TTP), but prognosis is generally poorer despite plasma exchange. The enzymatic activity of the plasma metalloprotease ADAMTS13, which cleaves ultralarge thrombogenic multimers of von Willebrand factor (VWF) derived from activated endothelial cells, is very low or undetectable in patients with classic TTP, and protease deficiency is thought to play a mechanistic role in the formation of platelet thrombi in the microcirculation. This is the first prospective study to evaluate the incidence of TMA in 46 consecutively recruited patients undergoing autologous or allogeneic BMT and explore in parallel the behaviour of ADAMTS13, VWF antigen and VWF multimer size. The incidence of post‐BMT TMA was 6% (three of 46); all cases occurred after allogeneic BMT. Compared with baseline values plasma ADAMTS13 activity was significantly reduced in patients undergoing BMT, particularly after the conditioning regimen (mean values: 50 ± 22 vs. 77 ± 32%; P < 0·0001). In the three patients who developed TMA, ADAMTS13 decreased after conditioning, but was very low in one case only (8%). VWF antigen levels progressively increased after the conditioning regimen (228 ± 75 vs. 178 ± 76% at baseline, P = 0·002). The mean proportion of high‐molecular weight VWF multimers did not change in the various stages of BMT, even though ultralarge multimers were transiently found in same cases with and without TMA. Hence, the measurements evaluated in this study are not clinically useful to predict the occurrence of post‐BMT TMA.

Health‐related quality of life and psychological well‐being in elderly patients with haemophilia

Summary.  Many persons with severe haemophilia reach seniority thanks to effective treatment. There is no information on health‐related quality of life (HRQoL) of these patients, who had lived for many years when regular replacement therapy was unavailable. Italian patients with severe haemophilia aged ≥65 years born in the 1940s or earlier were compared with men without bleeding disorders matched for age and geography. HRQoL was assessed via generic and disease‐specific questionnaires. Potential associations with concomitant illnesses, orthopaedic status, physical functioning, cognitive status and depression were evaluated. In addition, the newly adapted HRQoL questionnaire specific for elderly persons with haemophilia (Haem‐A‐QoLEldlery) was psychometrically tested and validated. Thirty‐nine patients, aged 65–78 years, were investigated, 33 with haemophilia A and six with haemophilia B, and compared to 43 controls, aged 65–79 years. Chronic blood borne viral infections, hypertension and arthropathy were more frequent in patients, whereas hypercholesterolemia and cardiovascular diseases were more frequent in controls. Psychometric characteristics of Haem‐A‐QoLElderly showed good to excellent values for reliability and validity. HRQoL was worse in patients at EQ‐VAS, WHOQOL‐BREF and WHOQOL‐Old. The highest impairments were found in patients by means of the haemophilia‐specific Haem‐A‐QoLElderly in such dimensions as ‘physical activity & leisure’, ‘physical health’ and ‘view’. A poor orthopaedic status was negatively associated with HRQoL. Compared to age‐matched controls elderly patients with haemophilia had an impaired HRQoL in association with their health status. The newly developed Haem‐A‐QoLElderly proved to be a reliable and valid instrument for HRQoL assessment in elderly haemophilia patients.

Central nervous system bleeding in patients with rare bleeding disorders

Summary.  Central nervous system (CNS) bleeding is one of the most severe and debilitating manifestations occurring in patients with rare bleeding disorders (RBDs). The aim of this study was to retrospectively collect data on patients affected with RBDs who had CNS bleeding, to establish incidence of recurrence, death rate, neurological sequences, most frequent location, type of bleeding and efficacy of treatments. Results pertained to 36 CNS bleeding episodes in 24 patients with severe deficiency except one with moderate factor VII (FVII) deficiency. Six patients (25%) experienced a recurrence and two had more than one recurrence. Seven patients (29%) had an early onset of CNS bleeding before the first 2 years of life, others (71%) later in life. In 76% of cases, CNS bleeding was spontaneous. CNS bleeding was intracerebral in 19 cases (53%), extracerebral in 10 (28%) and both intracerebral and extracerebral in two cases (6%). Neurosurgery was performed in 11 cases, in association with replacement therapy in seven cases. Seizures were noted in four patients. Residual psychomotor abnormalities were seen in two patients. No death was recorded. To prevent recurrence, 17/24 patients (71%) were put on secondary prophylaxis. In conclusion, recurrence of CNS bleeding was confirmed to be relatively frequent in patients with severe FV, FX, FVII and FXIII deficiencies. Most patients were managed with replacement therapy alone, surgery being reserved for those with worsening neurological conditions. Our results indicate that some RBDs require early prophylactic treatment to prevent CNS bleeding. Optimal dosage and frequency of treatment need further evaluation.

Hyperhomocysteinemia and C677T MTHFR Genotype in Patients With Retinal Vein Thrombosis

Introduction: Elevated homocysteine (Hcy) is associated with the risk of deep vein thrombosis, pulmonary embolism, ischemic heart disease, and stroke. Several studies have suggested that hyperhomocysteinemia (HHcy) may predispose to retinal vein thrombosis (RVT) development. The aim of this study is to investigate the relationship between Hcy, C677T methylenetetrahydrofolate reductase (MTHFR) genotype, and RVT in patients compared with controls. Materials and Methods: We evaluated the Hcy plasma level of 3114 consecutive participants in 2 Italian centers during a 2-year period. Hyperhomocysteinemia was found in 99 patients and 136 healthy participants. Of the 99 patients, 20 had RVT with a high prevalence of HHcy in the RVT subgroup (20.2%). This result suggested a possible relationship between HHcy and RVT development. We investigated 105 consecutive patients with recent diagnosis of RVT, and we compared them with 226 healthy controls to evaluate whether HHcy may be a risk factor for RVT. Results: the prevalence of HHcy was higher in patients compared with controls (34.3% vs 14.2%; P < .001). The MTHFR C677T genotype was found in 69 of 105 (65.7%) patients with RVT (heterozygosity: 40 of 105 and homozygosity: 29 of 105). The control group showed the presence of MTHFR C677T genotype in 169 of 226 participants (74.8%; heterozygosity: 100 of 226 and homozygosity: 69 of 226) without difference between the 2 groups (P = .08). Conclusion: our study suggests that HHcy is a possible risk factor for RVT development, while no association was found between RVT and the C677T MTHFR genotype.

Gynaecological and obstetrical problems in women with different bleeding disorders

Summary.  The aim of this case–control study was to analyse the prevalence of gynaecological, obstetrical and other more general bleeding symptoms in 114 women affected by various inherited bleeding disorders, who were compared with 114 apparently healthy women. Retrospective information were collected by means of two specific questionnaires, one on gynaecological and obstetrical bleeding symptoms, with special focus on the presence of menorrhagia as defined by a pictorial blood loss assessment chart (PBAC); and the other on general bleeding symptoms, whose severity was graded by means of the bleeding score (BS). Compared to normal women, the whole group of women with inherited bleeding disorders had a higher prevalence of excessive bleeding at menarche (25% vs. 5%, P < 0.0001) and menorrhagia (59% vs. 46%, P = 0.06). Affected women also had a higher frequency than controls of general bleeding symptoms that scored as severe by a BS ≥ 12 (49% vs. 0%, P < 0.0001). In affected women, the BS increased according to the severity of the haemostasis defect. In conclusions, the BS and the PBAC are simple tools to evaluate the severity of general bleeding symptoms and menorrhagia in women with inherited bleeding disorders. These instruments may help to identify those women for whom a therapeutic intervention is warranted.