Silent embolism in diagnostic cerebral angiography and neurointerventional procedures: a prospective study

Abstract

Background: Cerebral angiography is associated with a small but definite risk of neurological complications with an unknown incidence of clinically silent embolism. We assessed the neurological complication rate compared with the frequency of silent embolism after angiography

Methods: We used diffusion-weighted magnetic resonance imaging (MRI) before and after angiography to assess embolic events. 100 consecutive angiographies (66 diagnostic and 34 interventional procedures) were done on 91 patients. Patients underwent neurological assessment before, immediately after, and 1 day after angiography.

Findings: Before angiography, no abnormalities were seen on diffusion-weighted MRI. Diffusion-weighted MRI showed 42 bright lesions in 23 patients after 23 procedures (17 diagnostic, six interventional) in a pattern consistent with embolic events. There was no new neurological deficit after any angiographic procedure. After diagnostic angiography in patients with a history of vasculopathy, the frequency of lesions was significantly higher than in patients without vascular risk factors (12 [44%] of 27 vs five [13%] of 39 patients, p=0.03). In diagnostic angiography, the appearance of lesions was significantly correlated with whether vessels were difficult to probe (p=0.01), amount of contrast medium needed (p<0.01), fluoroscopy time (p<0.01), and use of additional catheters (p=0.02).

Interpretation: After diagnostic and interventional cerebral angiography, embolic events are more frequent than the apparent neurological complication rate. In diagnostic procedures, the incidence of embolism is closely related to a vascular risk profile.