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Prevalence of Potential Risk Factors for Stroke Assessed by Transesophageal Echocardiography and Carotid Ultrasonography: The SPARC Study


      The SPARC (Stroke Prevention: Assessment of Risk in a Community) study was designed to identify risk factors for stroke and cardiovascular disease using transesophageal echocardiography and carotid ultrasonography. This protocol was undertaken to establish a cohort in which putative risk factors for stroke were identified so that subsequent follow-up could discern the roles these risk factors play in stroke incidence.

      Subjects and Methods

      This was a prospective, population-based study. A randomly selected cohort comprised 1475 Olmsted County, Minnesota, residents aged 45 years or older, of whom 588 agreed to participate. Transesophageal echocardiography and carotid ultrasonography were used for evaluation of the subjects. Prevalences of various cardiovascular and cerebrovascular conditions were determined.


      Transesophageal echocardiography was successfully completed in 581 subjects. The prevalence (±SE) of patent foramen ovale was 25.6% (±1.9%), and that of atrial septal aneurysm was 2.2% (±0.6%). The prevalence of aortic atherosclerosis increased with age and was most common in the descending aorta, particularly in subjects 75 to 84 years old. The prevalence of strands on native valve was 46.4% (±2.2%). Carotid ultrasonography data for 567 participants revealed minimal atherosclerotic disease. Most subjects had minimal or mild carotid occlusive disease. The prevalence of moderate (50%-79%) and severe (80%-99%) stenosis was 7.7% (±1.1%) and 0.3% (±0.2%), respectively.


      This prospective study defines the prevalence of multiple potential cardiovascular and cerebrovascular risk factors, providing population-based data for ongoing follow-up of the risk of stroke.


      SPARC (Stroke Prevention: Assessment of Risk in a Community), TEE (transesophageal echocardiography)
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      Linked Article

      • Transesophageal Echocardiography in Source-of-Embolism Evaluation: The Search for a Better Therapeutic Rationale
        Mayo Clinic ProceedingsVol. 74Issue 9
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          The search for an underlying etiology in individual stroke patients is born of a desire to use safe and effective secondary preventive therapy specific to the cause of the initial event. Current estimates of the frequency of various etiologies of nonhemorrhagic stroke were recently reviewed authoritatively by Albers et al in the American College of Chest Physicians (ACCP) Consensus Conference on Antithrombotic Therapy (Figure 1).1 Initial attempts to distinguish among these causes begin with computed tomographic scanning to differentiate hemorrhagic from nonhemorrhagic stroke, neurologic and cardiovascular assessments (history, examination, electrocardiogram, chest radiograph), complete blood cell count with sedimentation rate and coagulation time, chemistry, and lipid studies, and a neurovascular study, usually with carotid duplex ultrasonography.
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