Cardiac microembolism: prevalence and clinical outcome

Area of Science:

• Cardiology
• Neurology
• Medical Imaging

Background:

• High intensity transient signals (HITS) detected via ultrasound suggest microembolic material in patients with vascular or cardiac conditions.
• Cardioembolic stroke is a significant concern, particularly in patients with specific cardiac histories.

Purpose of the Study:

• To investigate the prevalence of HITS in patients at high risk for cardioembolic stroke.
• To compare HITS occurrence and characteristics in different patient subgroups, including those with atrial fibrillation and prosthetic heart valves.

Main Methods:

• Ultrasound monitoring was used to detect HITS in 60 patients at risk for cardioembolic stroke and 20 control subjects.
• Patients were categorized into groups based on non-rheumatic atrial fibrillation (AFIB) and prosthetic valve surgery (with or without AFIB).

Main Results:

• HITS were absent in the control group. Group I (AFIB) showed 15% HITS prevalence; Groups II & III (prosthetic valves) showed 50% prevalence.
• Patients with mechanical prosthetic valves had a significantly higher HITS detection rate (61%) compared to those with bioprosthetic valves (11%).
• HITS intensity was higher in prosthetic valve patients, suggesting different embolic material, but no correlation with anticoagulation or valve position was found.

Conclusions:

• Microembolic signals are common in patients with mechanical prosthetic valves.
• HITS in patients with mechanical prosthetic valves did not appear to be a major prognostic factor for impending cardioembolic stroke.
• Further research may clarify the embolic material and prognostic significance of HITS in various cardiac patient populations.