Elsevier

The Lancet

Volume 354, Issue 9190, 6 November 1999, Pages 1594-1597
The Lancet

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

https://doi.org/10.1016/S0140-6736(99)07083-XGet rights and content

Summary

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.

Introduction

Diagnostic intra-arterial angiography of the cerebral vessels and neurointerventional procedures harbour a small but definite risk of neurological complications.1, 2, 3, 4, 5, 6 However, studies on the risks of cerebral angiography have taken only manifest new neurological deficits as complications. Clinically unapparent damage, such as microscopic air embolism7 or silent thromboembolism,8 had not been taken into account. Experimental and clinical studies have shown that diffusion-weighted magnetic resonance imaging (MRI) allows sensitive and early detection of cerebral ischaemia within minutes of onset.9, 10 We aimed to prospectively assess the apparent neurological complication rate compared with the clinically silent embolism rate on diffusion-weighted MRI.

Section snippets

Patients and procedures

100 intra-arterial angiographies of the cerebral vessels were done in 91 patients (41 men, 50 women, mean age 50 years [range 11–83]). Of these, 66 were diagnostic and 34 were interventional procedures. In all patients, the catheter was continuously flushed with saline unless a guidewire was used. The flushing system consisted of a high-pressure infusion system with a drop catheter (permanent pressure ⩾40 kPa) which was permanently attached to the catheter. In interventional procedures, the

Results

Before angiography no patient had a hyperintense lesion on diffusion-weighted MRI. After 23 angiograms (17 diagnostic, six interventional) in 23 patients (23% [95% CI 15–32]) 42 bright lesions were seen. No patient developed a new apparent neurological deficit after angiography. Size was less than 5 mm in 23 lesions, 5–10 mm in 12, and >10 mm in seven. Lesions were found only in vessel territories that had been studied during angiography (Figure 1, Figure 2, Figure 3). We saw only embolic types

Discussion

The risk of neurological complications after diagnostic angiography ranges from 0·55% to 3·2%.2 In patients with symptomatic carotid stenosis, a neurological complication rate as high as 10% has been reported.11 The definition of a neurological complication in previous studies has been a new focal deficit or change in mental status, but diffusion-weighted MRI has been used rarely to show a lesion in such patients.8

In our study, the frequency of lesions was correlated with the amount of contrast

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