Changes in serum calcium levels associated with catheter-based cerebral angiography

Digital subtraction angiography is performed with agents such as iodinated contrast and intravenous heparin, which can alter electrolyte levels. If severe enough, these alterations may produce symptoms in patients in the post-procedural period. We performed this study to evaluate serum calcium level changes after cerebral angiography.

The preangiographic and postangiographic serum calcium levels of 87 patients were reviewed and analyzed. Patients were grouped based on when the postangiographic serum calcium level was drawn in relation to the angiographic procedure (0-6 hours, 6-12 hours, 12-18 hours, and 18-24 hours).

A significant reduction in serum calcium was observed in the 0- to 6-hours, 6- to 12-hours, and 12- to 18-hours groups (P < .05). The differences between the preangiographic and postangiographic serum calcium levels were 0.91 mg/dL, 0.59 mg/dL, and 0.55 mg/dL in the 0- to 6-hours, 6- to 12-hours, and 12- to 18-hours groups, respectively. The difference in the 18- to 24-hours group (0.27 mg/dL) was not statistically significant. None of the patients was clinically symptomatic from this decrease in serum calcium levels.

An asymptomatic but significant decrease in serum calcium levels is seen following cerebral angiography. Possible mechanisms include chelation from the contrast agent or intravenous heparin. The reduction in serum calcium is transient, appearing to resolve within 24 hours.