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Transcranial Doppler detection of microemboli during percutaneous transluminal coronary angioplasty
C F Bladin1, L Bingham, L Grigg
1Department of Neurology, Royal Melbourne Hospital, Victoria, Australia.
Insights
Microemboli are common during percutaneous transluminal coronary angioplasty (PTCA) but are usually asymptomatic. These microemboli, often gaseous, do not appear linked to aortic atheroma or clinical events.
Area of Science:
- Cardiovascular Medicine
- Neurology
- Medical Imaging
Background:
- Percutaneous transluminal coronary angioplasty (PTCA) is a common procedure for coronary artery disease.
- Microemboli are known to occur during invasive cardiac procedures, but their occurrence during PTCA is not well studied.
- Neurological complications from microemboli are rare, but the link to PTCA specifically is unclear.
Purpose of the Study:
- To investigate the frequency and nature of microemboli during PTCA.
- To correlate microemboli detected during PTCA with aortic atheroma.
- To assess the clinical significance of microemboli during PTCA.
Main Methods:
- Twenty patients undergoing elective PTCA were monitored using transcranial Doppler (TCD) ultrasonography to detect microemboli in the left middle cerebral artery.
- Microembolic signal counts were correlated with PTCA procedure components.
- Transesophageal echocardiography (TEE) assessed aortic arch atheroma thickness in patients.
Main Results:
- A total of 973 microembolic signals were detected, with the majority (70%) occurring during solution injections.
- Contrast injection phases showed significantly higher microembolic signal counts compared to other phases (P<0.001).
- No neurological events were observed; a trend suggested a possible link between microemboli, aortic arch manipulation, and atheroma, but this was not statistically significant.
Conclusions:
- Microemboli are frequently detected by TCD during PTCA but are generally asymptomatic.
- The majority of microemboli are likely gaseous and not associated with the extent of aortic atheroma.
- Microemboli during PTCA do not appear to correlate with clinical events in this study.
Background And Purpose:
The use of percutaneous transluminal coronary angioplasty (PTCA) to treat coronary artery disease is now commonplace. The occurrence of microemboli during invasive procedures such as cardiac angiography and bypass surgery is well documented, although neurological complications are relatively uncommon. To date, no investigation has been undertaken of the frequency or nature of microemboli occurring during PTCA or of the correlation with aortic atheroma.
Methods:
Twenty patients having elective PTCA underwent examination by transcranial 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 each stage of the PTCA. Patients later underwent transesophageal (TEE) echocardiography, with measurements made of the thickness of the intima and atheroma in the ascending and descending thoracic aortic arch by cardiologists blinded to the TCD results.
Results:
A total of 973 microembolic signals were detected (mean+/-SD, 48.7+/-36.7 per patient); 196 (20%) occurred on movement of the PTCA catheter and wire around the aortic arch, 84 (9%) with other PTCA catheter-associated movements, and 679 (70%) in association with injection of solutions (eg, saline and contrast). Mean signal counts during contrast injection were significantly greater than during the other 3 phases (P<0.001). No neurological events occurred in the study. Although not statistically significant, there was a trend toward greater microembolic signal counts with the number of times the catheter was passed around the aortic arch and the amount of arch atheroma detected by transesophageal echocardiography.
Conclusions:
Microemboli detected on TCD are a common occurrence during PTCA but are largely asymptomatic. The majority of microembolic signals are most probably gaseous in origin and do not appear to be related to the extent of aortic atheroma or to clinical events.