Introduction Patients with pulmonary arteriovenous malformations (PAVMs) usually have underlying hereditary haemorrhagic telangiectasia (HHT), when iron deficiency often develops due to recurrent nasal and gastrointestinal haemorrhage. Iron deficient PAVM/HHT patients have more ischaemic strokes and venous thromboemboli. However, recent UK data indicate that cerebral abscesse are more common in PAVM patients using intravenous iron and/or with high normal transferrin saturation index.¹ Furthermore,~1 in 20 HHT patients report that iron treatments exacerbate their nosebleeds.² The goal of this study was to evaluate clinical patterns of iron treatments in patients with PAVMs and HHT.

Methods Iron, red cell and microbiology indices were evaluated as part of routine clinic assessments of patients with PAVMs and/or HHT. With ethical approval, all available patient datasets between 04/2015 and 07/2017 were recorded, categorised according to patient status, and analysed using STATA IC v13 (Statacorp, Texas).

Results At first assessment, 72 patients were using oral iron alone, and 21 were using intravenous iron +/-iron tablets. As noted in figure 1, intravenous iron users had lower haemoglobin concentrations than oral iron users, despite higher serum ferritin. None of the 16 selected PAVM patients evaluated had positive blood cultures in the clinic, or developed positive cultures following ex vivo iron treatments. Three of seven selected patients had low serum haptoglobin (0.32–0.36 g/L, reference range 0.5–2.4 g/L) potentially indicative of shortened intravascular red cell survival. 31 patients were commenced on oral or intravenous iron, or recommended a dose increase, but 56 were advised dose reduction. Post assessment, daily iron dosages tended to be lower (elemental iron content 14–130, median 35 mg/day) than at first assessment (elemental iron content 14–260, median 65 mg/day, p=0.08). In two patients, external clinicians advised that iron dose reduction led to at least temporary cessation of blood transfusion requirements. Reported nosebleed improvements were common, though may have also been due to intervening treatment of PAVMs.²

Conclusions Further study on the clinical efficacy and sequelae of iron treatments, and a more personalised approach to therapy, appears warranted in this patient group.

References

1. Boother, et al. Clin Infect Dis2017. doi:10.1093/cid/cix373

2. Shovlin, et al. ERJ Open Res2016;2(2).00035–2016.