Nobuhiko Ichinose

Carotid artery stenting for vulnerable plaques on MR angiography and ultrasonography: utility of dual protection and blood aspiration method

Background Carotid artery stenting (CAS) for internal carotid artery (ICA) stenosis with vulnerable plaques is controversial. We analyzed the effect of a dual protection and blood aspiration method during CAS in patients with vulnerable plaques. Methods A total of 111 patients with ICA stenosis underwent CAS using the dual protection (simultaneous flow reversal and distal filter) and blood aspiration method. In 103 of 111 patients, preoperative carotid plaque was estimated by both 3 T MRI and ultrasonography (US). ICA plaques with a high intensity signal on time-of-flight-MR angiography (TOF-MRA) and/or mobile component on US were defined as vulnerable plaques. We assessed major adverse events (MAE) (ie, major stroke, myocardial infarction, and death) and hyperintense spots on diffusion-weighted images (DWI) after CAS. We then evaluated the visible debris captured by dual protection and blood aspiration during CAS. Results The preoperative ICA plaque on TOF-MRA and US was judged to be vulnerable in 48.5% (50/103 patients). The success rate of the CAS procedure was 100% with no MAE within 30 days. DWI showed small hyperintense spots in 18% (9/50 patients) and 18.9% (10/53 patients) in the vulnerable and non-vulnerable plaque groups, respectively. Visible debris was captured in 68% (34/50 patients) and 45.3% (24/53 patients) in the vulnerable and non-vulnerable plaque groups, respectively (p=0.0286). Conclusions The combination of dual protection and blood aspiration could provide effective distal embolic protection although vulnerable plaques on TOF-MRA and US had a high incidence of debris during CAS. Thus, CAS using dual protection and blood aspiration is safe in patients with vulnerable plaques.

Vascular Wall Imaging of Unruptured Cerebral Aneurysms with a Hybrid of Opposite-Contrast MR Angiography

BACKGROUND AND PURPOSE: Inflammation and degeneration of the intracranial saccular aneurysm wall play a major role in aneurysm formation, development and subsequent rupture. The aim of this study was to characterize the walls of unruptured intracranial aneurysms by using a hybrid of opposite-contrast MRA at 3T. MATERIALS AND METHODS: Fourteen consecutive patients with 17 unruptured intracranial aneurysms who initially underwent clipping surgery were prospectively evaluated. All aneurysms were scanned preoperatively by using a hybrid of opposite-contrast MRA in 3T high-resolution MR imaging. We classified intraoperative findings of atherosclerotic plaques in the aneurysms into 3 grades: grade A (major plaques), grade B (minor plaques), and grade C (no plaques). The contrast ratio of the high-intensity area was also measured relative to the background low-intensity area inside the carotid artery. RESULTS: Findings from preoperative plaque imaging of the aneurysm corresponded to the intraoperative findings in 15 of 16 aneurysms (excluding 1 that was impossible to visualize in its entirety due to anatomic reasons). Overall sensitivity and specificity of the hybrid of opposite-contrast MRA were 88.9% and 100%, respectively. During the operation, 4 aneurysms were classified as grade A; 5, as grade B; and 7, as grade C. The means of the contrast ratio for grades A, B, and C were 0.72 ± 0.03, 0.34 ± 0.30, and −0.02 ± 0.09, respectively. CONCLUSIONS: The hybrid of opposite-contrast MRA can detect visible atherosclerotic plaques in the unruptured aneurysm wall, and the contrast ratio in intracranial aneurysms correlated with their presence and extent. A study including a larger series is needed to validate the diagnostic potential of this imaging technique.

Somatosensory evoked potentials in carotid artery stenting: Effectiveness in ascertaining cerebral ischemic events

Somatosensory evoked potentials (SSEP) have been used in various endovascular procedures and carotid endarterectomy, but to our knowledge no literature deals exclusively with the utility of SSEP in carotid artery stenting (CAS). The purpose of this study was to evaluate the efficacy of SSEP in detecting cerebral ischemic events during CAS. We conducted a prospective study in 35 CAS procedures in 31 patients during an 18month period. Thirty-three patients without near occlusion underwent stenting using dual protection (simultaneous flow reversal and distal filter) combined with blood aspiration, while two patients with near occlusion underwent stenting without dual protection. All 35 patients underwent SSEP monitoring. SSEP were generated by stimulating median and/or tibial nerves and recorded by scalp electrodes. During the aspiration phase post-dilation, seven patients (20%) exhibited SSEP changes with a mean duration of 11.3±8.5minutes (range: 3-25minutes), three of whom later developed minor stroke/transient ischemic attack. Diffusion-weighted imaging showed new lesions in 10 patients (28.6%). Change in SSEP exhibited mean sensitivity of 100% (95% confidence interval, 0.29-1.0) and specificity of 88% (95% confidence interval, 0.71-0.96) in predicting clinical stroke post-CAS. Intra-procedural SSEP change was predictive of post-procedural complications (p=0.005, Fishers exact test). Longer span of SSEP change was positively correlated with complications (p=0.032, Mann-Whitney test). Intra-procedural SSEP changes are highly sensitive in predicting neurological outcome following CAS. Chances of complications are increased with prolongation of such changes. SSEP allows for prompt intra-procedural ischemia prevention measures and stratification to pursue an aggressive peri-procedural protocol for high risk patients to mitigate neurological deficits.

Endovascular Stenting under Cardiac and Cerebral Protection for Subclavian Steal after Coronary Artery Bypass Grafting Due to Right Subclavian Artery Origin Stenosis.

Coronary-subclavian steal (CSS) can occur after coronary artery bypass grafting (CABG) using the internal thoracic artery (ITA). Subclavian artery (SA) stenosis proximal to the ITA graft causes CSS. We describe a technique for cardiac and cerebral protection during endovascular stenting for CSS due to right SA origin stenosis after CABG. A 64-year-old man with a history of CABG using the right ITA presented with exertional right arm claudication. Angiogram showed a CSS and retrograde blood flow in the right vertebral artery (VA) due to severe stenosis of the right SA origin. Endovascular treatment of the right SA stenosis was planned. For cardiac and cerebral protection, distal balloon protection by inflating a 5.2-F occlusion balloon catheter in the SA proximal to the origin of the right VA and ITA through the right brachial artery approach and distal filter protection of the right internal carotid artery (ICA) through the left femoral artery (FA) approach were performed. Endovascular stenting for SA stenosis from the right FA approach was performed under cardiac and cerebral protection by filter-protection of the ICA and balloon-protection of the VA and ITA. Successful treatment of SA severe stenosis was achieved with no complications.

Detection of in-stent protrusion (ISP) by intravascular ultrasound during carotid stenting: Usefulness of stent-in-stent placement for ISP

ObjectivesAs in-stent protrusion (ISP) during carotid artery stenting (CAS) may cause postoperative embolism, ISP detection is important. Intravascular ultrasound examination (IVUS) is useful for ISP detection because the blood vessel cross-section can be drawn as a tomogram from the lumen. Our objective was to clarify the occurrence of ISP during CAS using IVUS and relevant factors, and to report the usefulness of stent-in-stent placement when treating ISP.MethodsIn 142 consecutive patients (128 men, average age 71.7 years; 69 symptomatic) who underwent CAS using dual protection and the blood aspiration method, and subsequent IVUS after stent placement were included. The outcome of CAS, and the occurrence rate of ISP and related factors (plaque characteristics, stent design, intraoperative debris capture rate and postoperative diffusion-weighted imaging (DWI) positive rate) were examined.ResultsAll CAS procedures were successful and no major adverse events (MAEs) were observed at 30 days. ISP was found in 12% (17/142), and stent-in-stent placement was performed in all cases. Vulnerable plaques were observed in 12 of 17 ISP cases (71%). A closed stent was used in 13 of 17 ISP cases (71%). The intraoperative debris capture rate was 100%, and no neurological symptoms were observed in any patients. A significant increase in ISP susceptibility was related to vulnerable plaques and the intraoperative debris capture rate.ConclusionsVulnerable plaques and debris capture were significantly correlated with ISP occurrence. In all ISP cases, stent-in-stent placement was performed and good results were obtained.Key Points• ISP detection during CAS using IVUS is important.• ISP-positive patients were correlated with NASCET ≥ 80%, vulnerable plaques and stent length.• Adequate additional treatment of stent in stenting under reliable protection against ISP-positive patients achieved low perioperative complications.

Overlapped Stenting Is Associated with Postoperative Hypotension after Carotid Artery Stenting

BACKGROUND Hypotension (HT) is well recognized to frequently occur during and after carotid artery stenting (CAS), which sometimes causes postoperative complications such as stroke or myocardial infarction. This study aimed to examine the risk factors associated with HT after CAS based on the hypothesis that overlapped stenting may affect postoperative HT. METHODS A total of 106 lesions in 95 patients with carotid artery stenosis who underwent CAS were reviewed. Bradycardia and HT were defined as a heart rate and a systolic blood pressure less than 60 beats/min and 100 mm Hg, respectively. The patients were categorized by the presence (group H) or the absence (group N) of postoperative HT, respectively, and demographic data, risk factors, conditions of carotid artery stenosis, procedures, and pre- and intraoperative hemodynamics were compared between these 2 groups. Multivariate analysis was performed to evaluate independent factors associated with postoperative HT. RESULTS In total, postoperative HT was observed in 30 (28.3%) cases. The incidence of overlapped stenting, the use of an open-cell stent, and intraoperative HT were significantly higher in group H (P = .03, .01 and < .01, respectively). The distance from carotid bifurcation and the maximum stenotic lesion tended to be shorter in group H (P = .09). In the multivariate logistic regression analysis, using all these variables, the overlapped stenting and intraoperative HT were found to be independent predictors for postoperative HT. CONCLUSION The overlapped stenting affected postoperative HT after CAS. Blood pressure should be strictly controlled in cases with overlapped stenting or intraoperative HT after CAS.