Subclavian steal phenomenon (SSP) is a well-known atherosclerotic disease. It is due to stenosis/occlusion of the innominate or subclavian artery which is usually treated with percutaneous transluminal angioplasty and stenting. However, the moment of intraoperative flow direction change in vertebral artery is unknown. In this study, we used intraoperative duplex ultrasonography (DUS) of the ipsilateral vertebral artery to detect flow direction change and microembolic signals (MES). Intraoperative DUS were continued on pre-dilatation, stenting and post-dilatation. The technician’s hand was protected from radiation with a special protector. Six patients were included. Four patients underwent left subclavian artery stenting, one patient had right subclavian artery stenting and one patient had innominate artery stenting. In 4 patients, SSP was normalized when balloon-stent was open, and in one patient, SSP was normalized after pre-dilatation. Only one patient had post-dilatation, after that SSP was normalized and MES was observed. It is controversial whether intraoperative vertebral artery protection for subclavian artery stenting is necessary or not. In this study, immediately after deflation of stenting balloon, vertebral artery flow became anterograde. In the case of plaque rupture, there is a possibility of plaque embolization. In addition, one patient showed MES after post-dilatation. This suggests vertebral artery protection might be necessary.
Background and Purpose: Transcranial Doppler (TCD) is a noninvasive and effective technique for the measurement of cerebrovascular function. Measurement of breath holding index (BHI) in the middle cerebral artery is commonly performed to determine cerebrovascular reactivity. Nevertheless, a notable drawback of TCD is the absence of a transtemporal acoustic bone window. The submandibular window offers an alternative way to measure BHI. Here, we studied the diagnostic accuracy of cerebrovascular reactivity (CVR) in the internal carotid artery (ICA) as measured from the submandibular window. Methods: Twenty-five volunteers (13 male, 12 female) with sufficient temporal acoustic bone windows were assessed. BHI was measured by mean blood velocities before and after breath holding. The correlation of BHI measured in ICA (BHIi) and ipsilateral middle cerebral artery (BHIm) was assessed. Results: The mean age of the participants was 39.9 ± 13.7 years. The mean BHIm and BHIi values were 0.93 ± 0.29 and 0.92 ± 0.32, respectively. Spearman’s correlation coefficient between BHIm and BHIi was 0.665 (p = 0.0003). The cutoff point of the BHIi value for CVR impairment determined by BHIm was 0.71 (sensitivity 80.0%, specificity 80.0%). Conclusion: Measuring BHI from the submandibular window may be a useful procedure in the case of temporal bone window insufficiency.
A 79-year-old man was admitted to our hospital because of mild right hemiparesis and was diagnosed with cerebral infarction caused by left internal carotid artery stenosis. He was treated with dual antiplatelet therapy. The preoperative left carotid angiogram showed 95% stenosis by the NASCET (North American Symptomatic Carotid Endarterectomy Trial) criteria. Carotid artery stenting (CAS) was performed on 21 days after onset. The postoperative carotid ultrasound showed findings of protrusion in the stent. On the mode of color-Doppler, clear delineation of this structure was not possible due to the color blurs in the stent. On the other hand, superb micro-vascular imaging (SMI) clearly demonstrated the protrusion and the neovascularization in the plaque excluded by the stent. The present case suggests that intraplaque neovascularization might be associated with plaque protrusion in CAS.
Patent foramen ovale (PFO) is associated with cerebral embolism of unknown embolic source and migraine, and recently, percutaneous catheter closure has been performed. PFO is confirmed by color Doppler echocardiography as a short-circuiting blood flow signal across atrial septum. However, PFO remains closed at rest in most cases, and color Doppler may not be able to visualize the short-circuiting blood flow. Transesophageal echocardiography (TEE) microbubble test is usually used to detect PFO. However, TEE is an invasive procedure, and the insertion of the probe interferes with adequate Valsalva stress. In this study, we investigated the diagnostic accuracy of PFO in noninvasive transthoracic echocardiography (TTE) microbubble tests. Forty-seven patients (29 males and 18 females, mean age 66.3 years) underwent simultaneous TTE and TEE microbubble tests between July 2018 and December 2019. Results showed that 44 patients (93.6%) had concordant microbubble test determinations of TTE and TEE. Microbubble test by TTE was a useful screening test for the diagnosis of PFO.