The incidence of hypomagnesaemia following abdominal aortic aneurysm surgery.

INTRODUCTION: Magnesium is important for cardiac function. Hypomagnesaemia is associated with a higher incidence of arrhythmias and poorer outcomes in cardiac surgery. No studies have investigated the incidence or impact of postoperative hypomagnesaemia after abdominal aortic aneurysm (AAA) surgery. We aim to assess the incidence of hypomagnesaemia after AAA repair in our population. METHODS: Retrospective analysis was performed of patients who underwent elective AAA surgery at a single vascular centre. The last 110 patients undergoing open or endovascular AAA repair were identified. The hospital pathology system was used to identify the immediate postoperative serum magnesium levels as well as patient demographics and admission details. Hypomagnesaemia was defined as serum magnesium of <0.7 mmol/l. RESULTS: A total of 211 patients were studied and there were 3 deaths. Of the patients included, 101 underwent open elective AAA repair and 110 underwent endovascular repair. In the elective open repair group, 73 patients (73%) were hypomagnesaemic. In the endovascular repair group, 35 (32%) had hypomagnesaemia. A t-test showed a statistically significant difference in hypomagnesaemia between the open and endovascular groups (p<0.001). CONCLUSIONS: AAA surgery is associated with a high incidence of postoperative hypomagnesaemia, which is significantly greater among open repair patients. This is likely to have an effect on cardiac activity and lead to cardiac complications such as arrhythmias and poorer postoperative outcomes, especially in the open AAA repair subgroup. This stresses the importance of serum magnesium and cardiac monitoring in the postoperative phase. A prospective study is proposed to further investigate these findings, and their potential implications on perioperative morbidity and mortality.