TRANSCRANIAL DOPPLER DETECTION OF MICROEMBOLI DURING PERCUTANEOUS TRANSLUMINAL CORONARY ANGIOPLASTY

Background and Purpose-The use of percutaneous transluminal coronary a ngioplasty (PTCA) to treat coronary artery disease is now commonplace. The occurrence of microemboli during invasive procedures such as card iac angiography and bypass surgery is well documented, although neurol ogical complications are relatively uncommon. To date, no investigatio n has been undertaken of the frequency or nature of microemboli occurr ing during PTCA or of the correlation with aortic atheroma. Methods-Tw enty patients having elective PTCA underwent examination by transcrani al Doppler ultrasonography (TCD) to detect left middle cerebral artery microemboli occurring during the procedure. Blinded off-line analysis correlated microembolic signal counts on TCD with the components of e ach stage of the PTCA. Patients later underwent transesophageal (TEE) echocardiography, with measurements made of the thickness of the intim a and atheroma in the ascending and descending thoracic aortic arch by cardiologists blinded to the TCD results. Results-A total of 973 micr oembolic signals were detected (mean+/-SD, 48.7+/-36.7 per patient); 1 96 (20%) occurred on movement of the PTCA catheter and wire around the aortic arch, 84 (9%) with other PTCA catheter-associated movements, a nd 679 (70%) in association with injection of solutions (eg, saline an d contrast). Mean signal counts during contrast injection were signifi cantly greater than during the other 3 phases (P<0.001), No neurologic al events occurred in the study. Although not statistically significan t, there was a trend toward greater microembolic signal counts with th e number of times the catheter was passed around the aortic arch and t he amount of arch atheroma detected by transesophageal echocardiograph y. Conclusions-Microemboli detected on TCD are a common occurrence dur ing PTCA but are largely asymptomatic. The majority of microembolic si gnals are most probably gaseous in origin and do not appear to be rela ted to the extent of aortic atheroma or to clinical events.