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Abstract: SA-PO1029

Bioimpedance Vector Analysis (BIA) in Patients with Systemic AL Amyloidosis

Session Information

Category: Fluid, Electrolytes, and Acid-Base

  • 702 Water/Urea/Vasopressin, Organic Solutes

Authors

  • Rezk, Tamer, UCL Division of Medicine, London, United Kingdom
  • Davenport, Andrew, Royal Free Hospital, London, United Kingdom
  • Guillotte, Christianne, National Amyloidosis Centre, London, United Kingdom
  • Lachmann, Helen J., National Amyloidosis Centre, London, United Kingdom
  • Wechalekar, Ashutosh, National Amyloidosis Centre, London, United Kingdom
  • Hawkins, Philip N., National Amyloidosis Centre, London, United Kingdom
  • Gillmore, Julian D., National Amyloidosis Centre, London, United Kingdom
Background

Systemic AL amyloidosis is a progressive and fatal disease affecting the heart and kidneys in 50% and 70% of patients respectively. Fluid retention and sarcopenia from heart failure may be exacerbated by systemic chemotherapy(Sattianayagam. 2013) and influence management and prognosis. BIA has been validated in patients with CKD and cardiovascular disease(Davenport. 2012). We hypothesize that BIA is a superior method of detecting fluid retention and sarcopenia among patients with systemic AL amyloidosis than absolute change in weight.

Methods

All newly diagnosed patients with systemic AL amyloidosis attending the UK National Amyloidosis Centre from April 2016 to April 2017 who were enrolled into the ALCHEMY prospective observational study underwent body composition assessment via BIA using InBody 770 at baseline (n=193) and first follow up (n=58) in conjunction with routine clinical, biochemical and scintigraphy assessments.

Results

Median age was 68yr, M:F ratio 1:1. Median serum creatinine 98µmol/L, eGFR 62ml/min and NT-proBNP 2389ng/L. At baseline; median ECW/TBW ratio was 0.411 (normal range 0.36-0.39); 183/193 (95%) patients had ECW/TBW ratio above the normal range. SMM/h2 revealed severe sarcopenia in 0 (0%), moderate sarcopenia in 33 (17%) and normal muscle mass in 159 patients (87%) respectively (NHANES III). There was a correlation between baseline plasma NT-proBNP and ECW/TBW ratio (Pearson correlation 0.337 p<0.001).

Follow up BIA revealed median weight loss of 3kg (4%), ECW/TBW ratio increase of 0.008 (2%) and SMM loss of 1kg (2%). Follow up SMM/h2 revealed severe sarcopenia in 1 (2%), moderate sarcopenia in 14 (24%) and normal muscle mass in 43 (74%) patients respectively. Again, there was a correlation between percentage change in ECW/TBW ratio and percentage change in Log NT-proBNP at 6 months (Pearson correlation 0.4673, p<0.008).

Conclusion

BIA is a non-invasive method of assessing fluid excess and sarcopenia in patients with systemic AL amyloidosis at baseline and follow up. Significant fluid retention and sarcopenia were present in 93% and 17% at baseline and both worsened during or shortly after systemic chemotherapy. Since sarcopenia is increasingly recognised to be an independent risk factor for treatment intolerance, BIA may help minimise treatment toxicity in systemic AL amyloidosis.