Variability of Doppler Microembolic Signal Counts in Patients With Prosthetic Cardiac Valves

Abstract

The detection of microembolic signals in patients with prosthetic cardiac valves is a reproducible technique. The reliable performance of the neuronal network argues for a broader use of this device. The intrasubject stability of the microembolic rate over 1 year supports the concept that the underlying emboligenic process is associated with intrinsic mechanical properties of the valve implant and not due to a thromboembolic process in the heart.

Clinical Correlations of Doppler Microembolic Signals in Patients With Prosthetic Cardiac Valves

“…Obviously, monitoring prosthetic valve carriers immediately after symptom onset would be preferable. Still, the report of Georgiadis et al, 6 who found .insignificant differences in MES counts in 50 patients examined on three different occasions within one year, suggests that the MESgenerating mechanism is stable, and thus the methodology of the present study acceptable.…”

“…The resulting use of various Doppler equipment and evaluation of MES counts by more than one observer constitute a weakness of the present study. However, as the interobserver variability in MES counts in patients with prosthetic valves is low, 6 particularly through the high MES intensity in these patients, 7 this limitation is not likely to have greatly influenced our results. monitoring in 79% of cases, and the fact that neurologically symptomatic patients were not routinely monitored over the cerebral vessel supplying the affected territory or immediately after onset of neurological symptoms, constitute further methodological weaknesses.…”

Mechanisms of Cerebrovascular Events as Assessed by Procoagulant Activity, Cerebral Microemboli, and Platelet Microparticles in Patients With Prosthetic Heart Valves

“…Transcranial Doppler ultrasonography is able to detect signals representing microemboli in the basal cerebral arteries. [7][8][9][10][11] Recent studies [12][13][14] have shown conspicuously high frequencies of such highintensity transient signals (HITS) in patients with PHV. The debate over whether these HITS are formed elements (eg, platelet aggregates) or gaseous bubbles resulting from cavitation is still not settled, 12,13 and their clinical significance is disputed.…”

Occurrence and Clinical Impact of Microembolic Signals During or After Cardiosurgical Procedures

“…This hypothesis is supported by the stable number of MESs found during repeated investigations and the lack of patients' clinical deterioration over time. 6 Also, the rate of cardioembolic stroke in these patients does not appear to be correlated with the number of MESs detected. 15 No correlation could be identified between the patient's hemostaseology and either the number of MESs or the type and extent of antithrombotic treatment.…”