The Effects of Hypomagnesemia Post Heart Transplantation

PurposeThe calcineurin inhibitors (CNIs), including tacrolimus and cyclosporine, have revolutionized heart transplantation (HTx) in terms of maintaining low rejection rates. However, CNIs have significant side effects, such as nephropathy, hypertension, malignancy, and hypomagnesemia. It is this hypomagnesemia that has not been addressed as to whether this has an impact on outcome after HTx. Hypomagnesemia has been involved in muscle cramping and cardiac arrhythmias. Therefore, we reviewed our HTx patients and their magensium (Mg) levels to assess outcome in the first 6 months after HTx.MethodsBetween 2010 and 2020, we assessed 956 HTx patients and recorded their Mg levels in the first 6 months after HTx. Patients with low Mg levels less than or equal to 1.8 mg/dL were assessed for complications including muscle cramping, cardiac arrhythmias, rehospitalization, and rejection episodes. Patients with low Mg levels were grouped into mildly low Mg levels (1.7-1.8 mg/dL) and moderately low Mg levels (1.4-1.7 mg/dL). Patients were compared to control patients who had normal Mg levels (>1.8 mg/dL) during this period of time.ResultsPatients with mildly or moderately low Mg levels compared to patients with normal Mg levels had no difference in muscle cramping, rejection episodes, cardiac arrhythmias, or use of antihypertensive medications. Kidney function was clinically similar in all groups. There were more arrhythmias in the normal Mg group. Patients had an average of 32 blood draws to assess Mg levels.ConclusionMildly to moderately low hypomagnesemia did not have significant adverse effects in heart transplant patients. Aggressive Mg replacement may not be essential. The calcineurin inhibitors (CNIs), including tacrolimus and cyclosporine, have revolutionized heart transplantation (HTx) in terms of maintaining low rejection rates. However, CNIs have significant side effects, such as nephropathy, hypertension, malignancy, and hypomagnesemia. It is this hypomagnesemia that has not been addressed as to whether this has an impact on outcome after HTx. Hypomagnesemia has been involved in muscle cramping and cardiac arrhythmias. Therefore, we reviewed our HTx patients and their magensium (Mg) levels to assess outcome in the first 6 months after HTx. Between 2010 and 2020, we assessed 956 HTx patients and recorded their Mg levels in the first 6 months after HTx. Patients with low Mg levels less than or equal to 1.8 mg/dL were assessed for complications including muscle cramping, cardiac arrhythmias, rehospitalization, and rejection episodes. Patients with low Mg levels were grouped into mildly low Mg levels (1.7-1.8 mg/dL) and moderately low Mg levels (1.4-1.7 mg/dL). Patients were compared to control patients who had normal Mg levels (>1.8 mg/dL) during this period of time. Patients with mildly or moderately low Mg levels compared to patients with normal Mg levels had no difference in muscle cramping, rejection episodes, cardiac arrhythmias, or use of antihypertensive medications. Kidney function was clinically similar in all groups. There were more arrhythmias in the normal Mg group. Patients had an average of 32 blood draws to assess Mg levels. Mildly to moderately low hypomagnesemia did not have significant adverse effects in heart transplant patients. Aggressive Mg replacement may not be essential.