The role of transcranial Doppler ultrasonography (TCD) in individual risk a
ssessment of embolic complications and the development of prevention strate
gies during coronary angiography remains to be determined. The purpose of t
his study was to assess the prevalence, time of occurrence and potential si
gnificance of microembolic signals (MES) detected with TCD during femoral l
eft heart catheterization. TCD monitoring of the right and left middle cere
bral artery was performed in 51 consecutive patients (36 men, 15 women) who
were referred for coronary angiography. Percutaneous coronary angioplasty
was performed during the same procedure in 16 patients. MES were counted ma
nually during and after (offline analysis) the procedure. Two patients were
excluded from analysis because of the absence of an adequate acoustic temp
oral window. No neurological event occurred within 24 h in the 49 included
patients. MES were detected in all except 2 patients (mean number 17.1 +/-
12.8 per patient), mainly during left ventriculography (38%) and contrast m
edia injection into the coronary arteries (55%), suggesting their gaseous o
rigin. There was no statistically significant association between the numbe
r of MES and patient age, cardiovascular history and risk factors, or cathe
terization results. The presence of coronary artery disease was inversely r
elated to the number of MES (15.8 +/- 0.3 compared to 21.8 +/- 0.2 per pati
ent when a normal angiogram was present; p < 0.05). In conclusion, although
asymptomatic microemboli commonly occur during left heart catheterization,
the majority of them are probably of gaseous origin, since they occurred p
redominantly during contrast media injection in this study, and were not re
lated to cardiovascular history or to atheroma risk factors. Because air em
bolism has been reported to be harmful, attempts to reduce its occurrence d
uring catheter-based procedures could be pertinent. Copyright (C) 2001 S. K
arger AG, Basel.