Long-term follow-up of patients who underwent yttrium-90 pituitary implantation for treatment of proliferative diabetic retinopathy

Abstract

Between 1960 and 1976 117 patients underwent pituitary implantation with yttrium-90 (⁹⁰Y) for treatment of proliferative retinopathy at the Hammersmith Hospital, London. Mean age at operation was 35±11 years (mean±SD), and mean duration of diabetes 18.6±10.0 years. Mean insulin dosage prior to implant was 67.2±24 units, falling to 30.4±14.9 units post-implant. Thirty-two per cent of patients are still living, 60% are deceased and 8% are lost to follow-up. The 5-year survival rate was 82%. Of the causes of death, 21% died of infection, adrenal insufficiency or hypoglycaemia, 12% of renal failure, and 47% of myocardial or cerebral vascular disease. Ophthalmological follow-up was carried out on the 100 patients operated on between 1965 and 1976. The mean age of this group at implant was 35±10.5 years, and mean duration of diabetes 17.2±8.7 years. Visual acuity in the better eye at operation was 6/12 or better in 84% of patients, and this percentage remained similar at the time of the 5 and 10 year follow-up. Blindness (6/60 or worse) in both eyes was present in 12% of patients at the time of 5 and 10 year assessments. By 5 years new vessels on the disc had improved from a mean grading of 2.7±1.6 to 0.8±1.2 (p<0.001), and by 10 years there was no disc neovascularisation in any eye. There was a similar improvement in the grading of hard exudates, microaneurysms and haemorrhages, but there was an increase in fibrous retinitis proliferans. It is concluded that pituitary ablation was an effective method of treating proliferative retinopathy, and may have had a beneficial effect on other microvascular complications.