Hyponatremia Does Not Predict Adverse Outcomes In Patient With Left Ventricular Assist Devices

Abstract

Introduction Hyponatremia is common in heart failure and is a well-established indicator of adverse outcomes. The clinical implication of hyponatremia in left ventricular assist device (LVAD) patients remains understudied. We evaluated the association between pre-LVAD implant hyponatremia and one-year post LVAD outcomes. Methods Retrospective study of LVAD (exclusively HM 3 devices) implants between 8/2015 to 7/2020 at our institution. We divided our population based on their serum sodium the morning prior to LVAD implantation; Group 1: hyponatremia if <135 mEq/L and Group2: normal sodium if ≥135 mEq/L. We compared one-year outcomes between groups. Primary endpoint was a composite outcome of HF admission and mortality. Secondary endpoints were HF admissions, mortality and heart transplantation. In a secondary analysis, we compared outcomes between different sodium groups pre and post LVAD. Results A total of 195 patients were included. Mean age at implant was 52.2, male accounted for 78.5%, non-ischemic cardiomyopathy 74.4%. Preimplant hyponatremia was present in 40% with mean sodium of 132.1 vs 137.8 in the normal sodium group. Preimplant hyponatremia revealed no significant differences in any of the primary or secondary endpoints (Table 1). Secondary analysis comparing sodium groups pre vs. post LVAD (at discharge) also showed no differences in outcomes at one year (Table 2). Conclusion Neither pre-implant hyponatremia nor sodium groups at discharge were associated with adverse outcomes. This could be a result of adequate LV unloading and end organ perfusion which suggests other unclear mechanisms for ongoing hyponatremia. Regardless of the cause, these results suggest that optimization of mild hyponatremia may not be critical in LVAD patients and should not delay LVAD placement. Hyponatremia is common in heart failure and is a well-established indicator of adverse outcomes. The clinical implication of hyponatremia in left ventricular assist device (LVAD) patients remains understudied. We evaluated the association between pre-LVAD implant hyponatremia and one-year post LVAD outcomes. Retrospective study of LVAD (exclusively HM 3 devices) implants between 8/2015 to 7/2020 at our institution. We divided our population based on their serum sodium the morning prior to LVAD implantation; Group 1: hyponatremia if <135 mEq/L and Group2: normal sodium if ≥135 mEq/L. We compared one-year outcomes between groups. Primary endpoint was a composite outcome of HF admission and mortality. Secondary endpoints were HF admissions, mortality and heart transplantation. In a secondary analysis, we compared outcomes between different sodium groups pre and post LVAD. A total of 195 patients were included. Mean age at implant was 52.2, male accounted for 78.5%, non-ischemic cardiomyopathy 74.4%. Preimplant hyponatremia was present in 40% with mean sodium of 132.1 vs 137.8 in the normal sodium group. Preimplant hyponatremia revealed no significant differences in any of the primary or secondary endpoints (Table 1). Secondary analysis comparing sodium groups pre vs. post LVAD (at discharge) also showed no differences in outcomes at one year (Table 2). Neither pre-implant hyponatremia nor sodium groups at discharge were associated with adverse outcomes. This could be a result of adequate LV unloading and end organ perfusion which suggests other unclear mechanisms for ongoing hyponatremia. Regardless of the cause, these results suggest that optimization of mild hyponatremia may not be critical in LVAD patients and should not delay LVAD placement.