頸動脈病変の治療～stentとCEA～:内科の立場から

抄録

Evidence-based medicine (EBM) has been emphasized in Japan for these years. Several randomized controlled trials (RCTs) in North America and Europe provided evidence that carotid endarterectomy (CEA) is beneficial in patients with symptomatic severe carotid artery stenosis grater than 70% in diameter. The efficacy, however, has not yet been confirmed in Japan. Although carotid artery stenting is a less invasive intervention against carotid artery stenosis, a potential benefit of the stenting remains a matter of investigation. The CREST study, a large-scale RCT on-going in U.S.A. and Europe, will provide evidence concerning the effects of carotid stenting as compared to that of CEA in near future.
Carotid ultrasonography is a noninvasive and accurate way to evaluate carotid artery lesions. Transcranial Doppler ultrasonography and diffusion MRI are providing new insights how often are microembolic brain lesions produced during carotid artery stenting. The effects of several antithrombotic agents and HMG-CoA reductase inhibitor (statin) are now under investigations in ischemic stroke patients. These noninvasive measures and new medical management strategies will help us make carotid artery interventions safer and more effective.
Several clinical studies including J-MUSIC indicated that atherothrombotic brain infarction particularly due to extracranial carotid artery lesions has rapidly been increasing in frequency in Japan. However, the number of potential candidates for carotid intervention is estimated to be 1, 500 to 15, 000 annually in Japan, be-ing only 1/10 to 1/100 of that in U.S.A.
The current situation of carotid artery diseases and clinical evidence on the effectiveness and limitations of carotid interventions should be collected for Japanese patients with carotid lesions.