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The Journal of Heart and Lung Transplantation
International Society for Heart and Lung Transplantation.

Does Hemoglobin A1c Accurately Depict Diabetic Control in LVAD Patients?

      Purpose

      Diabetes is common in patients implanted with left ventricular assist devices (LVAD). Poor diabetic control increases infection risk, inflammatory markers, and thrombotic risk. Typical hemoglobin A1c (HbA1c) calculations rely on a normal red blood cell life span, which may result in an artificially low HbA1c. Fructosamine is a glycated protein product able to be extrapolated to estimated average glucose as HbA1c. The validity of these two values in the LVAD population is unknown.

      Methods

      A retrospective review on LVAD patients implanted from 2010 to 2021 was completed on patients with simultaneous fructosamine, LDH, and HbA1c levels. Patient characteristics, demographics, and diabetic history were collected and analyzed.

      Results

      Nine patients were implanted with HeartMate 2 (67%), HeartMate 3 (11%), and HeartWare (22%) devices. Most were male (67%), destination therapy (89%), with dilated cardiomyopathy (56%) etiology. HbA1c underestimated fructosamine-derived HbA1c values at higher fructosamine levels (p=0.0008) suggesting that HbA1c may underestimate average glucose (Figure 1). Levels of LDH appeared unrelated to the HbA1c or fructosamine values. .

      Conclusion

      These data demonstrate variability between calculated HbA1c derived from fructosamine and HbA1c blood levels in LVAD patients. At higher fructosamine levels, A1c may underestimate average glucose levels and falsely reassure about adequate glucose control. Alternative methodologies for assessing diabetic control, such as fructosamine, may be warranted, but further data should correlate average glucose values to these cumulative indices.