Jo Howard

Silent cerebral infarcts occur despite regular blood transfusion therapy after first strokes in children with sickle cell disease

Children with sickle cell disease (SCD) and strokes receive blood transfusion therapy for secondary stroke prevention; despite this, approximately 20% experience second overt strokes. Given this rate of second overt strokes and the clinical significance of silent cerebral infarcts, we tested the hypothesis that silent cerebral infarcts occur among children with SCD being transfused for secondary stroke prevention. A prospective cohort enrolled children with SCD and overt strokes at 7 academic centers. Magnetic resonance imaging and magnetic resonance angiography of the brain were scheduled approximately every 1 to 2 years; studies were reviewed by a panel of neuroradiologists. Eligibility criteria included regularly scheduled blood transfusion therapy. Forty children were included; mean pretransfusion hemoglobin S concentration was 29%. Progressive cerebral infarcts occurred in 45% (18 of 40 children) while receiving chronic blood transfusion therapy; 7 had second overt strokes and 11 had new silent cerebral infarcts. Worsening cerebral vasculopathy was associated with new cerebral infarction (overt or silent; relative risk = 12.7; 95% confidence interval, 2.65-60.5, P = .001). Children with SCD and overt strokes receiving regular blood transfusion therapy experience silent cerebral infarcts at a higher rate than previously recognized. Additional therapies are needed for secondary stroke prevention in children with SCD.

The Transfusion Alternatives Preoperatively in Sickle Cell Disease (TAPS) study: a randomised, controlled, multicentre clinical trial

BACKGROUND No consensus exists on whether preoperative blood transfusions are beneficial in patients with sickle-cell disease. We assessed whether perioperative complication rates would be altered by preoperative transfusion. METHODS We did a multicentre, randomised trial. Eligible patients were aged at least 1 year, had haemoglobin SS or Sβ(0)thalassaemia sickle-cell-disease subtypes, and were scheduled for low-risk or medium-risk operations. Patients were randomly assigned no transfusion or transfusion no more than 10 days before surgery. The primary outcome was the proportion of clinically important complications between randomisation and 30 days after surgery. Analysis was by intention to treat. FINDINGS 67 (96%) of 70 enrolled patients-33 no preoperative transfusion and 34 preoperative transfusion-were assessed. 65 (97%) of 67 patients had the haemoglobin SS subtype and 54 (81%) were scheduled to undergo medium-risk surgery. 13 (39%) of 33 patients in the no-preoperative-transfusion group had clinically important complications, compared with five (15%) in the preoperative-transfusion group (p=0.023). Of these, 10 (30%) and one (3%), respectively, had serious adverse events. The unadjusted odds ratio of clinically important complications was 3.8 (95% CI 1.2-12.2, p=0.027). 10 (91%) of 11 serious adverse events were acute chest syndrome (nine in the no-preoperative-transfusion group and one in the preoperative-transfusion group). Duration of hospital stay and readmission rates did not differ between study groups. INTERPRETATION Preoperative transfusion was associated with decreased perioperative complications in patients with sickle-cell disease in this trial. This approach could, therefore, be beneficial for patients with the haemoglobin SS subtype who are scheduled to undergo low-risk and medium-risk surgeries. FUNDING NHS Blood and Transplant.

Myocardial tissue characterization and the role of chronic anemia in sickle cell cardiomyopathy

To use cardiovascular magnetic resonance (CMR) techniques to examine possible causes for the left ventricular (LV) dilatation that occurs in sickle cell disease (SCD), including the effects of chronic anemia, iron‐induced cardiomyopathy, and regional fibrosis due to sludge infarcts that occur during sickle crises.

The obstetric management of sickle cell disease.

Sickle cell disease (SCD) is the most common inherited disease worldwide and is associated with anaemia and intermittent severe pain. Pregnant women who are affected have increased maternal and fetal mortality and morbidity. In view of this obstetricians should have an awareness of this condition and its complications, and pregnancies in women with SCD should be managed by a multidisciplinary team with experience of high risk pregnancies. Ideally women should be seen preconceptually for optimisation of their SCD and partner screening. Antenatal care should include regular outpatient visits with regular monitoring for pre-eclampsia and of fetal growth. Blood transfusion should be used for the treatment of acute anaemia, acute chest syndrome or acute stroke but there is not sufficient evidence currently to recommend its use prophylactically. There is an increased prevalence of sickle crisis during pregnancy and patients should be monitored carefully throughout this time.

Guideline on the management of acute chest syndrome in sickle cell disease

1. Department of Haematology, Guy’s and St Thomas’ NHS Foundation Trust 2. Lane Fox Respiratory Unit, St Thomas’ Hospital, Guy’s and St Thomas’ NHS Foundation Trust 3. Department of Haematology, North Middlesex Hospital 4. Department of Paediatric Haematology, Bristol Royal Hospital for Children 5. Department of Haematological Medicine, King’s College Hospital 6. Department of Haematology, Whittington Hospital

Cannabis use in sickle cell disease: a questionnaire study

Cannabinoids are increasingly being considered for the management of various painful conditions, and could be considered as an option for treating acute pain in sickle cell disease (SCD). The objective of this study was to determine the extent of use of cannabis in the community for pain and other symptom relief, and its side effects during self‐administration in patients with SCD. Patients attending Central Middlesex Hospital in London were invited to complete a structured self‐administered anonymous questionnaire. Eighty‐six young adults with HbSS, HbSC and HbSβthalassaemia disease (median age 30 years) participated in the study. Results showed that 31 (36%) had used cannabis in the previous 12 months to relieve symptoms associated with SCD. The main route in all but two patients was by smoking. The main reasons for use were to reduce pain in 52%, and to induce relaxation or relieve anxiety and depression in 39%. Symptoms related to sedation and mood effects were reported in 77% of patients. The majority of patients (58%) expressed their willingness to participate in studies of cannabis as a medicine. We conclude that research in the use of cannabinoids for pain relief in SCD would be both important and acceptable to adult patients.

Pregnancy outcome in patients with sickle cell disease in the UK – a national cohort study comparing sickle cell anaemia (HbSS) with HbSC disease

We describe the findings from a national study of maternal and fetal outcomes of pregnancy in women with sickle cell disease (SCD). Data were collected via the United Kingdom Obstetric Surveillance System between 1 February 2010 and 31 January 2011 from 109 women, of whom 51 (46·8%) had HbSS and 44 (40·4%) had HbSC. Data included antenatal, maternal and fetal outcomes. Comparisons were made between women with HbSS and HbSC. Incidence of complications were acute pain (57%), blood transfusion (26%), urinary tract infection (UTI; 12%) and critical care unit admission (23%) and these were all more common in women with HbSS than HbSC. There was no difference in the incidence of acute chest syndrome, hypertension and venous thromboembolism between HbSS and HbSC. Women with HbSS were more likely to deliver at <37 weeks gestation (P = 0·01) and their babies were more likely to have reduced birth weight. Delivery at <34 weeks was increased in both HbSS and HbSC women (5·9% vs. 4·6%) compared to national data. This study confirms a high rate of maternal and fetal complications in mothers with SCD, even in women with HbSC, which has previously been considered to have a more benign phenotype in pregnancy.

A phase 1 study of prasugrel in patients with sickle cell disease: Effects on biomarkers of platelet activation and coagulation

INTRODUCTION Prasugrel, a P2Y₁₂ adenosine diphosphate (ADP) receptor antagonist effectively inhibits ADP-mediated platelet activation and aggregation, and may be useful in reducing vaso-occlusive crises in sickle cell disease (SCD). In this study, we assess the effect of prasugrel on biomarkers of platelet activation and coagulation in patients with SCD. MATERIALS AND METHODS Twelve adult patients with SCD and 13 healthy subjects were examined before and after 12 ± 2 days of 5.0 or 7.5 mg/day oral prasugrel. Assessed cellular biomarkers included monocyte- and neutrophil-platelet aggregates, activated glycoprotein IIb-IIIa (GPIIbIIIa), P-selectin, CD40 ligand (CD40L), tissue factor (TF) expression on circulating platelets and on monocyte-platelet aggregates, and platelet-erythrocyte aggregates. Soluble biomarkers included CD40L, prothrombin fragment 1.2 (F1.2), thromboxane B₂ (TXB₂), P-selectin, and TF. RESULTS Patients with SCD had increased platelet baseline activation compared to healthy subjects, as measured by percentages of monocyte-platelet aggregates, neutrophil-platelet aggregates, and platelets expressing CD40L. Likewise, baseline levels of soluble F1.2 and TXB₂ were elevated in patients with SCD compared to healthy subjects. After 12 days of prasugrel, patients with SCD had a significant reduction in platelet-monocyte aggregates that was not observed in healthy subjects. Following prasugrel administration, those with SCD maintained higher levels of monocyte-platelet aggregates and soluble F1.2, but had lower levels of platelet-erythrocyte aggregates and soluble TF compared to healthy subjects. CONCLUSIONS These results provide evidence for chronic platelet activation in the SCD steady state, activation that was in part attenuated by prasugrel, thereby suggesting that ADP may mediate platelet activation in SCD.

The association between tricuspid regurgitation velocity and 5‐year survival in a North West London population of patients with sickle cell disease in the United Kingdom

Raised tricuspid regurgitant velocity (TRV) occurs in approximately 30% of adults with sickle cell disease (SCD), and has been shown to be an independent risk factor for death. TRV was assessed in 164 SCD patients who were subsequently followed up for survival. Raised pulmonary pressures were defined as a TRV jet ≥2·5 m/s on echocardiography. Elevated TRV was present in 29·1% of patients and it was associated with increased age and left atrial diameter. There were 15 deaths (9·1%) over a median of 68·1 months follow up; seven patients had increased TRV, and eight patients had a TRV<2·5 m/s. Higher TRV values were associated with a greater than 4‐fold increased risk of death (Hazard Ratio: 4·48, 99% confidence interval 1·01‐19·8), although we found a lower overall mortality rate than has been reported in previous studies. TRV was not an independent risk factor for death. We have confirmed the association between raised TRV and mortality in a UK SCD population whose disease severity appears to be less than that reported in previous studies. Further prospective studies are needed to more clearly characterize which patient factors modify survival in SCD patients with raised TRV.

The presence of α-thalassaemia trait blunts the response to hydroxycarbamide in patients with sickle cell disease

Hydroxycarbamide (HC), although a key drug therapy in sickle cell disease (SCD), does not result in a clinical response in all patients. Increases in fetal haemoglobin (HbF) and mean corpuscular volume of erythrocytes are standard clinical measures of HC efficacy in SCD. Genetic studies have determined that the majority of HbF regulation occurs outside the β‐globin locus. Approximately 30% of SCD patients have co‐inherited α‐thalassaemia resulting in hypochromic and microcytic erythrocytes. We provide data from 30 SCD patients (10 with α‐thalassaemia) demonstrating that co‐existing α‐thalassaemia significantly affects several standard measures of HC efficacy in SCD.