Carotid Duplex Ultrasound Imaging Research Articles

Changes in Carotid Duplex Ultrasound Velocities After Aortic Valve Replacement for Severe Aortic Stenosis.

The peak systolic velocity (PSV) and end-diastolic velocity (EDV) obtained by carotid duplex ultrasound (CDU) imaging of the internal carotid arteries (ICAs) are parameters used to determine the severity of ICA stenosis. Severe aortic stenosis (AS) results in a parvus-et-tardus pattern on spectral Doppler waveforms; however, the impact of severe AS on CDU velocities is unclear. The purpose of this study was to assess the impact of severe AS on CDU velocities by evaluating changes in CDU velocities before and after aortic valve replacement (AVR) METHODS: A single-center retrospective review of patients with severe AS who underwent surgical AVR and who had preoperative and postoperative CDU examinations performed within 12 months of each other was conducted. Patients with any carotid intervention between the preoperative and postoperative CDU were excluded. We identified 92 patients who satisfied all inclusion criteria. The mean age was 72.2 years; 71.7% were men; the mean preoperative aortic valve area ± SD was 0.8 ± 0.2 cm2 ; and the mean time from preoperative to postoperative AVR CDU was 182.3 ± 98.4 days. The peak aortic valve gradient decreased from 62.5 to 22.0 mm Hg after AVR (P < .001); however, there were no significant changes in the PSV or EDV in either the right or left ICA. Although severe AS may cause characteristic changes in the spectral Doppler waveform on CDU imaging, there is no significant effect on the ICA PSV or EDV. Adjustments in velocity criteria to determine the degree of carotid artery stenosis in patients with substantial AS may not be necessary.

Carotid endarterectomy should not be based on consensus statement duplex velocity criteria

ObjectiveRandomized trials support carotid endarterectomy (CEA) in asymptomatic patients with ≥60% internal carotid artery (ICA) stenosis. The widely referenced Society for Radiologists in Ultrasound Consensus Statement on carotid duplex ultrasound (CDUS) imaging indicates that an ICA peak systolic velocity (PSV) ≥230 cm/s corresponds to a ≥70% ICA stenosis, leading to the potential conclusion that asymptomatic patients with an ICA PSV ≥230 cm/s would benefit from CEA. Our goal was to determine the natural history stroke risk of asymptomatic patients who might have undergone CEA based on consensus statement PSV of ≥230 cm/s but instead were treated medically based on more conservative CDUS imaging criteria. MethodsAll patients who underwent CDUS imaging at our institution during 2009 were retrospectively reviewed. The year 2009 was chosen to ensure extended follow-up. Asymptomatic patients were included if their ICA PSV was ≥230 cm/s but less than what our laboratory considers a ≥80% stenosis by CDUS imaging (PSV ≥430 cm/s, end-diastolic velocity ≥151 cm/s, or ICA/common carotid artery PSV ratio ≥7.5). Study end points included freedom from transient ischemic attack (TIA), freedom from any stroke, freedom from carotid-etiology stroke, and freedom from revascularization. ResultsCriteria for review were met by 327 patients. Mean follow-up was 4.3 years, with 85% of patients having >3-year follow-up. Four unheralded strokes occurred during follow-up at <1, 17, 25, and 30 months that were potentially attributable to the index carotid artery. Ipsilateral TIA occurred in 17 patients. An additional 12 strokes occurred that appeared unrelated to ipsilateral carotid disease, including hemorrhagic events, contralateral, and cerebellar strokes. Revascularization was undertaken in 59 patients, 1 for stroke, 12 for TIA, and 46 for asymptomatic disease. Actuarial freedom from carotid-etiology stroke was 99.7%, 98.4%, and 98.4% at 1, 3, and 5 years, respectively. Freedom from TIA was 98%, 96%, and 95%, freedom from any stroke was 99%, 96%, and 93%, and freedom from revascularization was 95%, 86%, and 81% at 1, 3, and 5 years, respectively. ConclusionsPatients with intermediate asymptomatic carotid stenosis (ICA PSV 230-429 cm/s) do well with medical therapy when carefully monitored and intervened upon using conservative CDUS criteria. Furthermore, a substantial number of patients would undergo unnecessary CEA if consensus statement CDUS thresholds are used to recommend surgery. Current velocity threshold recommendations should be re-evaluated, with potentially important implications for upcoming clinical trials.

The modified operative technique of partial eversion carotid endarterectomy

We report a modified operative technique termed partial eversion carotid endarterectomy (PECE). During a 9-year period (2006-2015), 352 patients underwent PECE. Indications for surgery, intraoperative details, and outcomes were recorded. The initial 185 patients had carotid duplex ultrasound imaging at 6weeks and then at 6, 12, and 24months. Subsequent patients had carotid imaging at 4 to 6weeks. Indications included stroke (76), transient ischemic attack (153), and amaurosis fugax (33); 58 patients were asymptomatic, and 32 patients had surgery before cardiac surgery. Median clamp time was 14minutes (interquartile range, 11.5-17minutes). Median total operation time was 41minutes (interquartile range, 31-72minutes). Outcomes included four transient ischemic attacks (1.2%), five strokes (1.4%), and two deaths at 30days (0.5%). No significant cranial nerve injuries or carotid restenosis was detected during follow-up. PECE is technically straightforward, with outcomes comparable to those of current operative techniques. Its advantages included reduced operative and carotid clamping time.

Valsartan prevents neointimal hyperplasia after carotid artery stenting by suppressing endothelial cell injuries

Objectives:Restenosis or neointimal hyperplasia remains an important complication after carotid artery stenting (CAS) for carotid artery stenosis. The purpose of this study was to examine if an anti-hypertensive drug, angiotensin receptor blocker (ARB), prevents post-CAS neointimal hyperplasia during the first 1-year period after CAS, and to clarify the possible mechanisms.Methods:Hypertension had been treated with a calcium channel blocker (CCB) and/or an ARB, valsartan, by the preference of the neurosurgeon in charge in our department. At admission to perform CAS, patients were assigned to normotensive, valsartan (hypertensive patients treated with valsartan with/without any kind of CCBs), and non-valsartan (hypertensive patients treated with any kind of CCBs without ARBs) groups. Post-CAS neointimal hyperplasia was evaluated by carotid duplex ultrasound imaging in terms of intima-media thickening (IMT), which was performed at pre-CAS and at 90, 180, 270, and 360 days post-CAS. Biomarkers of oxidative stress (8-hydroxy-2'-deoxyguanosine), inflammation (C-reactive protein, tenascin-C) and endothelial cell injury (von Willebrand factor [vWF] antigen) were measured at pre-CAS and at 1, 7, and 180 days post-CAS.Results:The non-valsartan group (n = 8) had a higher incidence of maximum in-stent IMT ≧ 1·1 mm compared with the normotensive group (n = 6). Valsartan (n = 9) significantly suppressed plasma vWF levels at 7 days post-CAS and decreased the incidence of maximum in-stent IMT ≧ 1·1 mm compared with the non-valsartan group, although clinical parameters were similar between the two groups. Other biomarkers were not significantly different among the three groups.Conclusions:These findings suggest that valsartan may prevent post-CAS neointimal hyperplasia possibly by suppressing endothelial cell injury.

Standardized protocols enable stroke recognition and early treatment of carotid stenosis

This study examined the effect of acute ischemic stroke (AIS) care coordination between vascular surgery andstroke neurology services with primary focus on acute patient stabilization and expeditious carotid endarterectomy (CEA). A standardized AIS protocol was instituted between vascular surgery and stroke neurology services in an academic hospital (group I) that included: (1) rapid patient evaluation and imaging inclusive of brain and carotid computed tomography/magnetic resonance angiography, carotid duplex ultrasound imaging or conventional arteriogram, or both; (2) patient admission to a dedicated stroke unit with minimum 1:2 intensive care nurse-to-patient staffing and a 24-hour available neurointensivist; (3) treatment of all patients with ipsilateral moderate or severe carotid stenosis by CEA with cervical block (158 [81%]) or general anesthesia (38 [19%]). Patient exclusion from undergoing expeditious CEA included (1) stroke in evolution, and (2) dense neurologic deficit or National Institutes of Health Stroke Scale score >15 (severe), or both. Comparisons of data were performed between group I patients and those treated in outlying hospitals (group II) for similar indications. All data were prospectively collected in a computerized database and outcomes evaluated retrospectively. From November 2002 to November 2012, 369 patients underwent CEA for AIS ≤1week of presentation. There were 192 patients in group I and 177 in group II. There were no differences in group I and II in mean stroke-to-CEA interval (3.4 vs 3.9days) or in the performance of eversion CEA (94% vs 97%), respectively. Intraoperative shunt use was greater in group I (28%) than in group II (18%; P= .021). Fewer total neurologic events (stroke or transient ischemic attack) occurred in group I (6 [3.1%] vs 14 [7.3%]; P= .03). No patients died in either group. Postoperative National Institutes of Health Stroke Scale scores available in group I patients showed improvement from preoperative baseline in mild and moderate stroke patients (P< .001). In patients with stable acute stroke, early CEA is feasible and relatively safe. Stroke or death occurs in only 1%, and most complications are of nonfatal cardiac origin. A standardized stroke team protocol that is inclusive of stroke neurologists and vascular surgeons allows for expeditious and safe CEA in the setting of an acute stroke.

Poor agreement in carotid artery stenosis detection by ultrasound between external offices and a vascular center

Carotid duplex ultrasonography is the prime investigation used to grade carotid artery stenosis in clinical routine. We compared the carotid ultrasound (US) scans performed externally with our results. This retrospective study included 288 patients who had been referred to our outpatient department and initially presented with an external carotid duplex scan report indicating carotid atherosclerosis. The external scans were analyzed and compared with our scans in respect of the accuracy of identification and quantification of stenosis, the criteria used to grade stenosis and the duplex criteria used. Weighted Kappa coefficients (K) were computed to quantify the agreement between internal and external findings. The majority of the external reports had been performed by radiologists [70.8 % (n = 204)], followed by specialists of internal medicine [19.4 (n = 56)] and by neurologists [9.8 % (n = 28)]. Only slight agreement was registered between the external reports and those performed at our institution with regard to the identification of stenosis (K = 0.2 for the left and K = 0.12 for the right side). Greater agreement was observed in respect of the level of stenosis (K = 0.42 for the right and K = 0.54 for the left side). Overestimation of the level of stenosis was registered for 45 % in the left internal carotid artery (ICA) and 36 % in the right ICA; the overestimation was most pronounced for occlusions and high-grade stenoses, which is a source of great concern for decision-making. The present data indicate only a slight agreement between carotid duplex US imaging performed at medical offices and our results.

Echolucent or predominantly echolucent femoral plaques predict early restenosis after eversion carotid endarterectomy

Although the association between vulnerable lesions and cardiovascular events is well established, little is known about their relationship to postsurgery restenosis. To address this issue, we initiated a prospective, nonrandomized study to examine the femoral plaques on both sides in patients who were undergoing eversion carotid endarterectomy (CEA) and were longitudinally followed-up for early restenosis development. The final analysis enrolled 321 patients (189 women) with a median age of 67.0 years (interquartile range, 59.0-73.0 years), who underwent eversion CEA (2005 to 2007). Using duplex ultrasound scanning, we evaluated 321 common femoral atherosclerotic lesions on the day before CEA. A quantitative scale was used to grade the size of plaques as grade 1, one or more small plaques (<20 mm2); grade 2, moderate to large plaques; and grade 3, plaques giving flow disturbances. The plaque morphology in terms of echogenicity was graded as echolucent, 1; predominantly echolucent, 2; predominantly echogenic, 3; echogenic 4; or calcified, 5. The plaque surface was categorized as smooth, irregular, or ulcerated. The patients underwent carotid duplex ultrasound imaging at 6 weeks and at 6, 12, and 24 months after CEA. Mann-Whitney U test, chi2 test, and multivariate logistic regression were used for statistical evaluation. Internal carotid artery restenosis of > or = 50% was detected in 33 patients (10.28%) in the operated region. Neither the size (grade 1, P = .793; grade 2, P = .540; grade 3, P = .395) nor the surface characteristics of the femoral plaques (smooth, P = .278; irregular, P = .281; ulcerated, P = .934) were significantly different between the patients with and without carotid restenosis. Echolucent-predominantly echolucent femoral lesions were an independent predictor of recurrent carotid stenosis (adjusted odds ratio, 5.63; 95% confidence interval, 2.14-10.89; P < .001). Ultrasound evaluation of femoral plaque morphology before CEA can be useful for identifying patients at higher risk for carotid restenosis.

Spontaneous recanalization of a middle cerebral artery occlusion with subsequent carotid endarterectomy

We report the case of a 55-year-old man who presented with a left hemisphere stroke. The initial computed tomography scan demonstrated a cerebral infarct in association with a left middle cerebral artery occlusion. Carotid duplex ultrasound imaging revealed a surgical grade stenosis of the proximal left internal carotid artery; however, in view of the uncertain benefits of internal carotid endarterectomy in the face of ipsilateral middle cerebral artery occlusion, surgery was deferred. Subsequent surveillance by transcranial Doppler imaging and repeat computed tomography demonstrated spontaneous recanalization. The patient proceeded to carotid endarterectomy with no complications.

Noninvasive Carotid Duplex Ultrasound Imaging for the Evaluation and Management of Carotid Atherosclerotic Disease

Renewed interest in surgical management of atherosclerotic disease of the carotid bifurcation underscores the necessity for accurate and efficacious means for diagnostic evaluation of patients with suspected carotid disease. Noninvasive testing by carotid duplex ultrasound, which combines high-resolution B-mode imaging with pulsed Doppler spectral analysis, is the method of choice. Noninvasive testing permits identification of potentially significant carotid stenosis, occlusion, or unstable plaque morphology with virtually no significant morbidity from the testing itself. Symptomatic patients, or patients with asymptomatic carotid bruits, can be evaluated serially to determine disease progression or response to medical management. In patients who are surgical candidates, substitution of noninvasive duplex ultrasound evaluation for carotid arteriography is controversial. Noninvasive testing is highly technique-dependent and probably requires at least 1 year of experience for acquisition of a sufficient "learning curve" for diagnostic reliability. This applies not only to the technical performance of the test but to interpretation of results. Proper training of technicians and quality assurance in individual vascular laboratories are crucial elements with respect to accuracy and reliability of results obtained in noninvasive testing.