Neuronal excitotoxicity after carotid angioplasty and stent placement procedures

To investigate if glutamate levels also increase in carotid angioplasty and stent placement (CAS) procedures, since high plasma glutamate levels are associated with ischemic infarction and transient ischemic attacks, but the length of ischemia needed to elicit such elevation has not been assessed.

All patients or their relatives signed informed consent. By using high-performance liquid chromatography, plasma glutamate concentrations were determined in 74 patients treated with CAS. Blood samples were obtained with arterial and peripheral venous catheterization before and after the procedure, and venous blood samples were obtained 24, 48, and 72 hours after CAS. Glutamate concentrations were also analyzed in two different control groups: 16 patients without carotid stenosis before and after diagnostic cerebral angiography and 20 patients treated with coronary angioplasty and stent placement. The χ(2) test, t test, and analysis of variance were used to compare glutamate concentrations among the groups.

Baseline glutamate concentrations were similar between patients who underwent CAS and both control groups. In CAS patients, glutamate concentrations in venous blood increased immediately after the procedure (354.1 μmol/L ± 132.8) and returned to baseline levels at 24 hours (129.5 μmol/L ± 56.8) (P < .0001). Glutamate concentrations remained unchanged over time in both control groups.

A rapid increase in plasma glutamate levels occurs after CAS procedures, unrelated to stroke.