Evaluation of Cryptogenic Stroke With Advanced Diagnostic Techniques

See related article, p 950.The term cryptogenic stroke generally refers to a stroke for which there is no specific attributable cause after a comprehensive evaluation for the most common causes. Cryptogenic stroke accounts for 23% to 40% of patients, more frequent in younger patients.1,2The issue of cryptogenic stroke is a relevant one for several reasons. First, prognosis—high risks of recurrence have been reported after cryptogenic stroke or transient ischemic attack (TIA).3,4 Second, perception—because no distinctive treatment is often recommended in patients with cryptogenic stroke, physicians and patients may otherwise not take adherence to prescribed treatments as seriously as they should given the high risk of recurrence. Third, and perhaps most importantly, advanced diagnostic techniques, including long-term monitoring to document paroxysmal atrial fibrillation (AF), high-resolution MRI technique to visualize wall pathology (ie, plaque, dissection, or vasculitis), and coronary computed tomographic angiography (CCTA) to evaluate aortocardiac embolism/concomitant coronary heart disease, might be useful in reducing the proportion of patients diagnosed with cryptogenic stroke, thereby facilitating the implementation of therapies targeting the underlying cause of the index stroke, especially because recurrent strokes are often of the same subtype as the preceding index stroke.The purpose of this review article is to present the most recent advances in diagnostic techniques that may be helpful in reducing the proportion of patients diagnosed with cryptogenic strokes.First, patients diagnosed with a cryptogenic stroke may have evidence of a mild degree of stenosis in vessels corresponding to the area of symptomatic vascular brain injury. However, even an artery with a mild degree of stenosis can harbor unstable plaque, which can rupture or erupt, resulting in stroke via arteroembolism. Indeed, it has been shown that thrombotic coronary artery occlusion usually follows rupture of an unstable plaque, and the at-risk …