R036

Parathyroidectomy in Chronic Kidney Disease 2006-11: Success comes at a price.

Nassim Parvizi, Neil S Tolley, Tricia Tan, Fausto Palazzo, Imperial Centre for Endocrinology

Abstract:

Hyperparathyroidism is a common consequence of chronic kidney disease (CKD). Whilst medical management has improved, many patients still develop irreversible hyperparathyroidism. Calcimimetics (Cinacalcet) are helpful but both expensive and carry a poor tolerance profile. The absolute indications for parathyroidectomy include hypercalcaemia and calciphylaxis but no level 1 evidence exists to support biochemical criteria for surgery. Furthermore, there is no universally accepted surgical strategy for patients with hyperparathyroidism in CKD. The National Kidney Foundation KDOQI guidelines previously included the calcium phosphate product as a risk for ectopic (mainly cardiovascular) calcification; currently the only additional guideline for surgery is a parathyroid hormone (PTH) level >88 pmol/L.

We retrospectively reviewed data on renal patients undergoing parathyroid surgery for renal disease between December 2006 and September 2011 at Hammersmith Hospital to assess the cause of the renal disease, dialysis history, medical therapy, indications for parathyroid surgery, biochemical results and morbidity post-operatively.

A total of 70 patients, 41 male (mean age 53.9 years) and 29 female (mean age 64.0 years) were included. The commonest causes of renal failure were diabetes mellitus (27%), hypertension (20%) and glomerulonephritis (16%). 52 (74%) patients were on cinacalcet therapy. The commonest indications for parathyroidectomy were: bone pain (35%), non-responsive to medical therapy (31%), hypercalcaemia/tertiary hyperparathyroidism (19%), fracture, brown tumours and calciphylaxis (9%). The surgical procedure performed was a total parathyroidectomy in 33% of patients. The remaining 67% underwent a subtotal parathyroidectomy with 38% having either undergone or awaiting renal transplantation. The median pre-operative PTH was 145 pmol/L, calcium 2.44 mmol/L, phosphate 1.31 mmol/L and alkaline phosphatase (ALP) 215 IU/L. Post-operatively their median levels were PTH 2.65 pmol/L, calcium 2.30 mmol/L, phosphate 1.04 mmol/L and ALP 143 IU/L. Five patients who underwent a subtotal parathyroidectomy had recurrence of whom three underwent a successful re-operation, one was adequately maintained on medical therapy and one passed away due to a myocardial infarction (MI). Another patient in this series also suffered from a post-operative MI.

In conclusion, the majority (86%) of our patients meet the modified international guidelines and undergo surgery that achieves the goal of debulking the parathyroid hormone excess.  Long term studies are required to determine the optimal surgical strategy in CKD.