Emma Prescott

Comparison of effects of oral deferiprone and subcutaneous desferrioxamine on myocardial iron concentrations and ventricular function in beta-thalassaemia

BACKGROUND Despite the introduction of the parenteral iron chelator desferrioxamine more than 30 years ago, 50% of patients with thalassaemia major die before the age of 35 years, predominantly from iron-induced heart failure. The only alternative treatment is oral deferiprone, but its long-term efficacy on myocardial iron concentrations is unknown. METHODS We compared myocardial iron content and cardiac function in 15 patients receiving long-term deferiprone treatment with 30 matched thalassaemia major controls who were on long-term treatment with desferrioxamine. Myocardial iron concentrations were measured by a new magnetic-resonance T2* technique, which shows values inversely related to tissue iron concentration. FINDINGS The deferiprone group had significantly less myocardial iron (median 34.0 ms vs 11.4 ms, p=0.02) and higher ejection fractions (mean 70% [SD 6.5] vs 63% [6.9], p=0.004) than the desferrioxamine controls. Excess myocardial iron (T2* <20 ms) was less common in the deferiprone group than in the desferrioxamine controls (four [27%] vs 20 [67%], p=0.025), as was severe (T2* <10 ms) iron overload (one [7%] vs 11 [37%], p=0.04). The odds ratio for excess myocardial iron in the desferrioxamine controls versus the deferiprone group was 5.5 (95% CI 1.2-28.8). INTERPRETATION Conventional chelation treatment with subcutaneous desferrioxamine does not prevent excess cardiac iron deposition in two-thirds of patients with thalassaemia major, placing them at risk of heart failure and its complications. Oral deferiprone is more effective than desferrioxamine in removal of myocardial iron.

Myocardial iron clearance during reversal of siderotic cardiomyopathy with intravenous desferrioxamine: a prospective study using T2* cardiovascular magnetic resonance.

Heart failure from iron overload causes 71% of deaths in thalassaemia major, yet reversal of siderotic cardiomyopathy has been reported. In order to determine the changes in myocardial iron during treatment, we prospectively followed thalassaemia patients commencing intravenous desferrioxamine for iron‐induced cardiomyopathy during a 12‐month period. Cardiovascular magnetic resonance assessments were performed at baseline, 3, 6 and 12 months of treatment, and included left ventricular (LV) function and myocardial and liver T2*, which is inversely related to iron concentration. One patient died. The six survivors showed progressive improvements in myocardial T2* (5·1 ± 1·9 to 8·1 ± 2·8 ms, P = 0·003), liver iron (9·6 ± 4·3 to 2·1 ± 1·5 mg/g, P = 0·001), LV ejection fraction (52 ± 7·1% to 63 ± 6·4%, P = 0·03), LV volumes (end diastolic volume index 115 ± 17 to 96 ± 3 ml, P = 0·03; end systolic volume index 55 ± 16 to 36 ± 6 ml, P = 0·01) and LV mass index (106 ± 14 to 95 ± 13, P = 0·01). Iron cleared more slowly from myocardium than liver (5·0 ± 3·3% vs. 39 ± 23% per month, P = 0·02). These prospective data confirm that siderotic heart failure is often reversible with intravenous iron chelation with desferrioxamine. Myocardial T2* improves in concert with LV volumes and function during recovery, but iron clearance from the heart is considerably slower than from the liver.

High prevalence of low bone mass in thalassaemia major

Cooleys original description of β‐thalassaemia major included marked bone deformities as a characteristic feature. These were thought to be due to expansion of haemopoiesis attempting to compensate for the congenital anaemia. Regular blood transfusions from infancy prevents these skeletal problems. Nevertheless, symptoms due to bone disease frequently occur in adult patients. Osteoporosis has not previously been reported as a cause of severe morbidity in thalassaemia major. The present study shows a high prevalence of low bone mass among thalassaemia major patients and analyses the predisposing causes. Bone density scans were performed in 82 patients with transfusion‐dependent β thalassaemia. Factors known to be associated with low bone mass such as gender, endocrine disorders and lifestyle activities, together with factors specific to the thalassaemia and its management, were included in a series of univariate analyses to ascertain any significant associations. 42 (51%) of the patients had severely low bone mass and a further 37 (45%) had low bone mass. The three factors showing a statistically significant association with severely low bone mass were male sex, 24/38 (63%) males had severely low bone mass, compared with 18/44 (41%) females, the lack of spontaneous puberty, 22/32 (69%) who required therapeutic induction of pubertal development had severely low bone mass, compared with 19/47 (40%) with spontaneous puberty and diabetes, 8/10 (80%) diabetic patients had severely low bone mass, compared with 23/56 (41%) with normal glucose tolerance. There was no association between the bone mineral density measurements and the haematological characteristics or treatment details of these patients. Severely low and low bone mass are common findings in patients with β‐thalassaemia major despite optimal transfusion and iron chelation. The associated features suggest that the severely low bone mass is due to endocrine abnormalities, in contrast to the haematological causes of bone disease characteristically seen in untreated thalassaemics.

Normalized left ventricular volumes and function in thalassemia major patients with normal myocardial iron

To determine the reference range in thalassemia major (TM) for left ventricular (LV) function.

Development of Thalassaemic Iron Overload Cardiomyopathy despite Low Liver Iron Levels and Meticulous Compliance to Desferrioxamine

It is believed that myocardial iron deposition and the resultant cardiomyopathy only occur in the presence of severe liver iron overload. Using cardiovascular magnetic resonance, it is now possible to assess myocardial and liver iron levels as well as cardiac function in the same scan, allowing this supposition to be examined. We describe a patient with progressive myocardial iron deposition and the development of early iron overload cardiomyopathy despite excellent compliance to standard subcutaneous desferrioxamine, minimal liver iron and well-controlled serum ferritin levels. These indirect markers remained far below the thresholds conventionally believed to be associated with increased cardiac risk.

Left ventricular diastolic function compared with T2* cardiovascular magnetic resonance for early detection of myocardial iron overload in thalassemia major

To compare left ventricular (LV) diastolic function with myocardial iron levels in beta thalassemia major (TM) patients, using cardiovascular magnetic resonance (CMR).

Prevalence of Low Bone Mass and Vitamin D Deficiency in β-Thalassemia Major

Abstract Low bone mass, a major cause of morbidity in patients with β-thalassemia major (β-TM), is multifactorial. There is lack of data about the current prevalence of low bone mass in patients with β-TM. The aims of this study are to examine the current prevalence of low bone mass in β-TM patients and the association between demographic characteristics, markers of iron overload, endocrinopathies, glycemic status and bone mineral density (BMD) as well as to study the 25-OH-vitamin D status of the patients and its relationship with BMD. Our institution serves the largest cohort of β-TM patients in the UK. From 99 patients (49 males, 50 females) with a mean ± standard deviation (SD) age of 36 ± 9 years, 55.5% had low BMD for their age as defined by Z-score BMD <−2.0 either at the lumbar spine (43.9%) or at the hip (25.5%). The only statistically significant association on the multivariate analysis was between hypogonadism and low BMD at the lumbar spine. In our study, 29.9% of patients had vitamin D deficiency, 65.7% had vitamin D insufficiency and 12.4% had optimal levels. No association between vitamin D status and low bone mass was found. Our study demonstrated a much lower prevalence of low bone mass in adults with β-TM compared to previous studies. Further studies are needed to examine whether this suggests a widespread improvement across patients with β-TM possibly due to advances in therapeutics. Most patients had suboptimal 25-OH-vitamin D levels, but no association between vitamin D status and bone mass was demonstrated.

History of myocardial iron loading is a strong risk factor for diabetes mellitus and hypogonadism in adults with β thalassemia major

Endocrinopathies are common complications of transfusional hemosiderosis among patients with β thalassemia major (TM). Previous studies had shown associations between some endocrinopathies and iron overload of the myocardium, liver and/or endocrine organs as assessed by MRI techniques. This retrospective analysis of 92 patients with TM (median age 36 yr) from a tertiary adult thalassemia unit in UK aimed to determine independent risk factors associated with endocrinopathies among these patients. Unlike previous studies, longitudinal data on routine measurements of iron load [worst myocardial and liver T2* values since 1999, worst LIC by MRI‐R2 since 2008 and average 10‐yr serum ferritin (SF)] up to April 2010 together with demographic features and age of initiating chelation were analyzed for associations with endocrinopathies. The most common endocrinopathies in this cohort were hypogonadism (67%) and diabetes mellitus (DM) (41%), and these were independently associated with myocardial T2* <20 ms (P < 0.001 and P = 0.008, respectively) and increased age (P = 0.002 and P = 0.016, respectively). DM and hypogonadism were independently associated with average SF >1250 μg/L (P = 0.003) and >2000 μg/L (P = 0.047), respectively. DM was also associated with initial detection of abnormal myocardial T2* at an older age (30 yr vs. 24 yr, P = 0.039). An abnormal myocardial T2* may therefore portend the development of DM and hypogonadism in patients with TM.

Joint diabetes thalassaemia clinic: an effective new model of care.

Abstract Diabetes is a significant complication of β-thalassemia major (β-TM) and most patients receive fragmented diabetes care. In 2005, we developed a unique Joint Diabetes Thalassaemia Clinic, based at the Department of Diabetes, Whittington Health, London, UK, where patients were reviewed jointly by a multidisciplinary team, including Consultant Diabetologist and Hematologist. Study of the Joint Diabetes Thalassaemia Clinic (2005–2009) showed improvement in glycemic control with fructosamine reduction from 344 umol/L to 319 umol/L over a 1-year period as well as improvement in lipid profiles. The proportion of patients attending the Joint Clinic who achieved metabolic targets compared to the National Diabetes Audit for England was higher for glycemic control (73.0 Joint Diabetes Thalassaemia Clinic vs. 63.0% nationally), blood pressure control (58.0 Joint Diabetes Thalassaemia Clinic vs. 30.0% nationally) and cholesterol control (81.0 Joint Diabetes Thalassaemia Clinic vs. 78.0% nationally). Five patients (22.7%) had microvascular complications. A significant proportion of our patients had endocrinopathies (86.0% hypogonadism, 18.0% hypothyroidism, 23.0% hypoparathyroidism). The unique partnership of our Joint Diabetes Thalassaemia Clinic, allowed these very complex patients to be managed effectively.