Prevalence of and risk factors for cerebral microbleeds among adult patients with haemophilia A or B.

INTRODUCTION: Cerebral microbleeds (CMBs) represent clinically silent haemorrhagic events. Cerebral microbleeds (CMBs) portend negative neurovascular and cognitive outcomes in the general population and are associated with cognitive impairment in persons with haemophilia (PWH). Prevalence, patterns, and risk factors for CMBs in PWH have not been directly compared to persons without coagulopathy. AIM: To examine prevalence, patterns, and risk factors for CMBs in PWH vs normal controls. METHODS: Adults with haemophilia A or B and haemostatically normal controls were recruited. Subjects were excluded if taking an antithrombotic agent other than low-dose aspirin (<100 mg). All subjects underwent T2*MRI of the brain; scans were reviewed independently by two neuroradiologists blinded to subject group to determine the presence of CMBs. RESULTS: We recruited 31 PWH and 32 controls. Human immunodeficiency virus (HIV) and history of hepatitis C virus (HCV) infection were more prevalent in PWH; smoking was more common among controls. Cardiovascular (CV) risk factors were similar between groups. Prevalence of CMBs was 35% in PWH and 25% in controls (P = .42). Among PWH, advanced age, history of HCV infection, and CV risk factors were associated with CMBs. Multiple and large (>5 mm) CMBs were seen only in PWH. CONCLUSIONS: Cerebral microbleeds (CMBs) are common in adults with haemophilia, but not clearly more prevalent than in haemostatically normal controls. In PWH, older age, HCV infection, CV risk factors, and the presence of an inhibitor were associated with CMBs. Large CMBs and multiple CMBs may be more prevalent in PWH than in the general population. The clinical impact of CMBs in PWH requires further study.

Recombinant factor VIIa addition to haemophilic blood perfused over collagen/tissue factor can sufficiently bypass the factor IXa/VIIIa defect to rescue fibrin generation.

INTRODUCTION: Factor VIII (FVIII) or factor IX (FIX)-deficient haemophilic patients display deficits in platelet and fibrin deposition under flow detectable in microfluidics. Compared to fibrin generation, decreased platelet deposition in haemophilic blood flow is more easily rescued with recombinant factor VIIa (rFVIIa), whereas rFVIIa requires FXIIa participation to generate fibrin when tissue factor (TF) is absent. AIMS: Perfusion of haemophilic whole blood (WB) over collagen/TF surfaces was used to determine whether rFVIIa/TF was sufficient to bypass poor FIXa/FVIIIa function in blood from patients with haemophilia A and B. METHODS: Whole blood treated with high-dose corn trypsin inhibitor (40 µg mL-1 ) from seven healthy donors and 10 patients was perfused over fibrillar collagen presenting low or high TF (TFlow or TFhigh ) at wall shear rate of 100 s-1 . RESULTS: With WB from healthy controls, platelet deposition and fibrin accumulation increased as TF increased. Factor-deficient WB (1-3% of normal) displayed striking deficits in platelet deposition and fibrin formation at either TFlow or TFhigh . In contrast, mildly factor-deficient WB (14-32%) supported fibrin formation under flow on TFhigh /collagen. With either TFlow or TFhigh , exogenously added rFVIIa (20 nm) increased platelet deposition and fibrin accumulation in WB from factor-deficient patients (1-3% of normal) to levels commensurate with untreated healthy WB. CONCLUSION: The absence of FIXa/FVIIIa in patients with severe haemophilia results in deficits in fibrin formation that cannot be rescued by wall-derived TF ex vivo. The effects of rFVIIa on platelet adhesion and rFVIIa/TF can act together to reinforce thrombin generation, platelet deposition and fibrin formation under flow.

Interventional therapies and in-hospital outcomes in acute coronary syndromes complicated by von Willebrand disease.

INTRODUCTION: von Willebrand disease (VWD) is one of the most common inherited bleeding disorders. AIM: Investigate the impact of the VWD bleeding tendency on in-hospital management of acute coronary syndromes (ACS). METHODS: Using discharge data from the National Inpatient Sample (NIS), the features of presentation and in-hospital treatment among ACS hospital discharges with and without a VWD diagnosis were investigated. A total of 264 case discharges and 705 860 control discharges were identified. RESULTS AND CONCLUSIONS: There was a significantly higher percentage of women among the case discharges compared to the control discharges (59.5% and 39.4%, respectively; P < 0.001). The rate of medical therapy alone [i.e. avoidance of percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG)] was significantly higher among unstable angina cases than controls (55.0% vs. 46.4%; P = 0.01), and among cases undergoing PCI, bare-metal stents (BMS) were utilized in preference to drug-eluting stents (DES) (adjusted OR = 3.5); P < 0.001). No difference in in-hospital death was identified, but reported bleeding among discharges that underwent CABG was higher in cases compared to controls (12.9% vs. 5.2%; P = 0.047). Although medical and interventional management of ACS appears to be well tolerated in the majority of hospitalized patients with VWD, the gender ratio is reversed, interventions and DES are utilized less frequently and procedure-related bleeding may be increased, calling for further study.

Evaluation of the utility of the ISTH-BAT in haemophilia carriers: a multinational study.

INTRODUCTION: There has been increasing recognition in recent years that female carriers of haemophilia manifest abnormal bleeding; however, data on the use of bleeding assessment tools in this population are lacking. AIM: Our objective was to validate the ISTH-BAT in haemophilia carriers to describe bleeding symptoms and allow for comparisons with factor levels and other patient groups. METHODS: This was a prospective, observational, cross-sectional study performed by members of Global Emerging HEmostasis Panel (GEHEP). Unselected consecutive haemophilia carriers were recruited and a CRF and the ISTH-BAT were completed by study personnel. RESULTS: A total of 168 haemophilia carriers were enrolled: 155 haemophilia A and 13 haemophilia B. The mean age was 40 years (range: 20-82). Carriers had higher mean bleeding scores (BS) compared with age-matched controls (n = 46; 5.7 vs. 1.43; P < 0.0001) and Type 3 VWD OC (n = 32; 3.0; P = 0.009), but lower BS compared with women with Type 1 VWD (n = 83; 8.7; P < 0.0001). Fifteen carriers reported haemarthrosis, and of those six had normal FVIII/FIX levels. There was a significant but weak negative correlation between BS and factor level (Spearman's r2  = -0.36, P < 0.001). CONCLUSION: Our results show that haemophilia carriers experience abnormal bleeding, including haemarthrosis. Overall, BS in women with Type 1 VWD > haemophilia carriers > Type 3 VWD OC > controls. Understanding the performance of the ISTH-BAT in this population is a critical step in future research aimed at investigating the underlying pathophysiology of abnormal bleeding, with the ultimate goal of optimizing treatment.

Presentation and management of acute coronary syndromes among adult persons with haemophilia: results of an international, retrospective, 10-year survey.

Sparse data are available on presentation and management of acute coronary syndromes (ACS), including unstable angina and non-ST- and ST-elevation myocardial infarction, among persons with haemophilia (PWH). The aim of this study was to determine demographics, bleeding disorder characteristics, cardiovascular risk factors (CRFs), interventions, haemostatic protocol, revascularization outcomes and complications among PWH with ACS. Members of an international consortium comprising >2000 adult PWH retrospectively completed case report forms for episodes of ACS in a >10-year follow-up period (2003-2013). Twenty ACS episodes occurred among 19 patients [rate, 0.8% (95% CI 0.4, 1.2)]. Seven patients (37%) were aged <50 years; 10 (53%) had ≥3 CRFs. In 5/20 episodes (25%), the initial ACS management protocol was altered because of the bleeding disorder. None of the eight patients with severe haemophilia underwent coronary artery bypass grafting (CABG), compared with 54.5% of patients with non-severe disease (P = 0.02). Revascularization with percutaneous coronary intervention (PCI) or CABG was rated successful in 13/13 cases, with no excessive bleeding during initial management. During chronic exposure to antiplatelet agents, secondary haemophilia prophylaxis was more prevalent in patients with severe haemophilia compared with non-severe haemophilia (85.7% vs. 30%, P = 0.05). No ACS-related deaths occurred during initial management, but one patient with severe haemophilia A died of undetermined cause 36 months after the ACS event while on aspirin therapy. ACS occurs even among relatively younger PWH, typically in association with multiple CRFs. Revascularization with PCI/CABG is feasible, and antiplatelet agents plus secondary prophylaxis appears to be well tolerated in selected PWH with ACS.

Recombinant factor VIIa enhances platelet deposition from flowing haemophilic blood but requires the contact pathway to promote fibrin deposition.

In prior microfluidic studies with haemophilic blood perfused over collagen, we found that a severe deficiency (<1% factor level) reduced platelet and fibrin deposition, while a moderate deficiency (1-5%) only reduced fibrin deposition. We investigated: (i) the differential effect of rFVIIa (0.04-20 nm) on platelet and fibrin deposition, and (ii) the contribution of the contact pathway to rFVIIa-induced haemophilic blood clotting. Haemophilic or healthy blood with low and high corn trypsin inhibitor (CTI, 4 or 40 µg mL(-1) ) was perfused over collagen at an initial venous wall shear rate of 100 s(-1) . At 100 s(-1) wall shear rate, where FXIIa leads to thrombin production without added tissue factor, FXI-deficient blood (3%) or severely FVIII-deficient blood (<1%) produced no fibrin at either CTI level. Whereas rFVIIa potently enhanced platelet deposition, fibrin generation was not rescued. Distinct from the high CTI condition, engagement of the contact pathway (low CTI) in moderately FVIII-deficient (3%) or moderately FIX-deficient blood (5%) resulted in enhanced platelet and fibrin deposition following 4 nm rFVIIa supplementation. In mildly FVIII-deficient blood (15%) at <24 h since haemostatic therapy, rFVIIa enhanced both platelet and fibrin generation in either CTI condition although fibrin was produced more quickly and abundantly in low CTI. For tissue factor-free conditions of severe haemophilic blood clotting, we conclude that rFVIIa reliably generates low levels of 'signaling' thrombin sufficient to enhance platelet deposition on collagen, but is insufficient to drive fibrin polymerization unless potentiated by the contact pathway.

Microfluidic assay of hemophilic blood clotting: distinct deficits in platelet and fibrin deposition at low factor levels.

BACKGROUND: Coagulation factor deficiencies create a range of bleeding phenotypes. Microfluidic devices offer controlled hemodynamics and defined procoagulant triggers for measurement of clotting under flow. OBJECTIVES: We tested a flow assay of contact pathway-triggered clotting to quantify platelet and fibrin deposition distal of dysfunctional thrombin production. Microfluidic metrics were then compared with PTT or % factor activity assays. METHODS: Whole blood (WB) treated with low level corn trypsin inhibitor (4 µg mL⁻¹) from nine healthy donors and 27 patients (deficient in factor [F] VIII, 19 patients; FIX, one patient; FXI, one patient; VWF, six patients) was perfused over fibrillar collagen at wall shear rate = 100 s⁻¹. RESULTS: Using healthy WB, platelets deposited within 30 s, while fibrin appeared within 6 min. Compared with healthy controls, WB from patients displayed a 50% reduction in platelet deposition only at < 1% factor activity. In contrast, striking defects in fibrin deposition occurred for patients with < 13% factor activity (or PTT > 40 s). Full occlusion of the 60-µm high channel was completely absent over the 15-min test in patients with < 1% factor activity, while an intermediate defect was present in patients with > 1% factor. CONCLUSION: Spontaneous bleeding in patients with < 1% factor activity may be linked to deficits in both platelet and fibrin deposition, a risk known to be mitigated when factor levels are raised to > 1% activity (PTT of ~40-60 s), a level that does not necessarily rescue fibrin formation under flow.

How we manage prostate biopsy and prostate cancer therapy in men with haemophilia.

A 56-year-old African American male with severe haemophilia A [baseline factor VIII (FVIII) activity <1%] and chronic hepatitis C virus infection started annual serial monitoring of prostate-specific antigen (PSA) at age 40 because of a family history of prostate cancer (his father died from the disease at age 63). His most recent PSA level was 4.4 ng L (-1); previous values were <3 ng L(-1 . Digital rectal examination was unrevealing.

Outcomes in total elbow arthroplasty in patients with haemophilia at the University of California, San Francisco: a retrospective review.

Severe haemophilic arthropathy of the elbow is a significant cause of morbidity among adults with haemophilia. However, previous reports of total elbow arthroplasty (TEA) in the haemophilic population have been based on small numbers of patients with relatively short-term follow-up. The records of seven total elbow arthroplasties in six adult men with haemophilia at the University of California, San Francisco who underwent TEA over a period of 25 years were retrospectively reviewed. Type of haemophilia, age at time of TEA, HIV infection status, pre- and postoperative range-of-motion (ROM) scores, complications (including infections), need for subsequent surgical revision and functional outcomes were recorded. Four patients had severe factor VIII deficiency and two patients had severe factor IX deficiency. None of the patients had an inhibitor. The mean age at the time of surgery was 34 years (range, 22-46 years) and the mean follow-up period was 118 months (range, 37-176 months). One of the six patients had TEA in both elbows. Five of the six patients were infected with HIV. There were no immediate perioperative complications. At a mean of 19.2 months postoperatively, ROM had improved in five of seven TEAs: mean flexion had increased from 110.7° (SD = 15.0) to 120.1° (SD = 14.5), whereas mean preoperative extension increased from -44.3° (SD = 21.5) to -36.9° (SD = 27.0). One patient required a revision at 30 months because of ulnar component loosening. This same patient sustained a staph epidermidis infection and ultimate removal of the prosthesis 15 years postoperatively. At a mean of 118 months postoperatively, five of six patients continued to report reduced pain and preserved functionality, with ability to perform normal daily activities. TEA resulted in favourable results in six of seven procedures. Our findings support the viability of TEA for individuals with severe haemophilic arthropathy of the elbow, especially to reduce pain and preserve or restore functionality.

T cell receptor VB repertoire diversity in patients with immune thrombocytopenia following splenectomy.

In recent years, a pathophysiological role for T cells in immune thrombocytopenia (ITP) has been established. We applied cDNA size distribution analysis of the T cell receptor (TCR) beta-variable (VB) complementarity-determining region 3 (CDR3) in order to investigate T cell repertoire diversity among immune thrombocytopenia patients who had either responded or not responded to splenectomy, and compared them to normal controls. ITP patients who had had a durable platelet response to splenectomy showed a mean 2.8 +/- 2.1 abnormal CDR3 size patterns per patient, similar to healthy volunteers (2.9 +/- 2.0 abnormal CDR3 size patterns). In contrast, patients unresponsive to splenectomy demonstrated evidence of significantly more clonal T cell expansions than patients who had responded to splenectomy or controls (11.3 +/- 3.3 abnormal CDR3 size patterns per patient; P < 0.001). Of the VB subfamilies analysed, VB3 and VB15 correlated with response or non-response to splenectomy, each demonstrating oligoclonality in non-responding patients (P < 0.05). These findings suggest that removal of the spleen may lead directly or indirectly to reductions in T cell clonal expansions in responders, or that the extent of T cell clonality impacts responsiveness to splenectomy in patients with ITP.

Raphespinal and reticulospinal neurons project to the dorsal vagal complex in the rat.

Stimulation of the caudal raphe nuclei alters visceral functions. The caudal raphe nuclei project to the nucleus of the solitary tract, which receives the central terminations of vagal afferents and plays an important role in the central integration of autonomic activities. The caudal raphe nuclei also project to the somatic and preganglionic autonomic motoneurons of the spinal cord. Diamidino yellow was injected into the nucleus of the solitary tract, and fast blue was injected into either the cervical, thoracic, or lumbar spinal cord. Large numbers of double-labeled neurons were present within the caudal raphe nuclei and the adjacent reticular formation of the medial tegmental field. This observation documents that individual raphespinal and reticulospinal neurons project an axon collateral to the nucleus of the solitary tract. These data demonstrate the anatomic substrate for global modulation of the autonomic motoneuron pool by the caudal raphe nuclei.