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Carotid Doppler high-intensity transient signals in dilated cardiomyopathy
V A Knappertz1, C H Tegeler, C D Furberg
1Department of Neurology, Yale University, New Haven, USA.
Insights
High-intensity transient signals (HITS) are not a reliable indicator of stroke risk in dilated cardiomyopathy (DCM) patients. This study found HITS prevalence in DCM was low and similar to healthy individuals, suggesting HITS monitoring is not viable for assessing thromboembolic risk.
Area of Science:
- Cardiology
- Neurology
- Vascular Ultrasound
Background:
- Thromboembolism is a serious complication in dilated cardiomyopathy (DCM).
- The efficacy of primary preventive antithrombotic or anticoagulation therapy remains undetermined.
- High-intensity transient signals (HITS) on Doppler ultrasound may indicate microemboli and increased stroke risk.
Purpose of the Study:
- To assess the feasibility, reproducibility, and prevalence of HITS in patients with DCM.
- To determine if HITS monitoring can serve as a surrogate marker for thromboembolic risk in DCM.
Main Methods:
- Prospective examination of 30 DCM patients (LVEF ≤35%, NYHA class II-III) and 20 controls, excluding those on antithrombotics or with specific comorbidities.
- One-hour Doppler recordings of the common carotid artery (CCA) performed on 3 separate days.
- Blinded, random reading of studies by 2 independent experts.
Main Results:
- HITS were detected in 20% of DCM patients and 15% of controls (not statistically significant).
- High intrareader and interreader reproducibility, but moderate to low intrasubject reproducibility.
- No significant difference in HITS characteristics between DCM patients and controls.
Conclusions:
- The prevalence of CCA HITS in stable DCM patients not on anticoagulation is low and similar to healthy individuals.
- HITS monitoring is not a viable surrogate marker for increased thromboembolic risk in this DCM population.
- Further research is needed to determine optimal antithrombotic strategies for DCM.
Background:
Thromboembolism is an infrequent but serious complication in dilated cardiomyopathy (DCM), and the role of primary preventive antithrombotic or anticoagulation therapy is undetermined. High-intensity transient signals (HITS) by Doppler ultrasound representing microemboli have been described in various clinical settings associated with increased risk of stroke. This study assessed the feasibility, reproducibility, and prevalence of HITS in patients with DCM.
Methods:
Thirty patients with severely reduced left ventricular ejection fraction (< or = 35%, mean 25%) and New York Heart Association class II to III who were not receiving antithrombotic or anticoagulant therapy and 20 age-matched normal subjects were prospectively examined. Patients with atrial fibrillation, significant cardiac valvular heart disease, a history of cerebrovascular disease, and those who otherwise required antithrombotic or anticoagulation therapy were excluded. One-hour pulsed-wave Doppler recordings over the common carotid artery (CCA) were performed on 3 separate days in each subject by a single, experienced, blinded sonographer with a 4-MHz probe (TC-2000, Nicolet/EME) with a specially designed probe holder. Studies were read in a blinded, random fashion by 2 independent, experienced HITS Doppler recording readers.
Results:
HITS in the CCA were detected in 6 (20%) of 30 patients with DCM and in 3 (15%) of 20 volunteers. This difference was not statistically significant. Intrareader and interreader reproducibility were high (kappa = 0.91 and 0.84, respectively; P <.001), whereas intrasubject reproducibility over the 3 visits was moderate to low (kappa = 0.22). There was no significant difference between HITS characteristics, that is, intensity and duration, in patients versus controls.
Conclusions:
The prevalence of CCA HITS in patients with clinically stable heart failure who are not receiving anticoagulation/antithrombotic therapy and are not in atrial fibrillation is low and not significantly different from normal patients. These data suggest that HITS monitoring is not a viable surrogate marker for increased thromboembolic risk in such patients with DCM.