Common Carotid Artery Internal Carotid Artery Research Articles

Effects of Neck Radiation Therapy on Carotid Arteries in Patients with Head and Neck Carcinoma

Background: Radiotherapy is a main treatment modality for cancers of the head and neck (HNC). However, it can cause a number of complications, including carotid artery damage.This study aimed to determine the effect of head and neck radiotherapy on carotid Doppler ultrasound findings in patients with HNC treated at Imam Hossein University Hospital. Materials and Methods: This research is a descriptive-longitudinal and prospective study conducted in 2022 on patients with HNC undergoing neck radiotherapy. In this study, before the initiation of radiotherapy, the patients underwent neck carotid artery Doppler ultrasound and various parameters including peak systolic velocity (PSV), end-diastolic velocity (EDV), internal carotid artery/common carotid artery (ICA/CCA) PSV, the number of plaques, intimal thickness, and percentage of carotid diameter stenosis, were recorded. The Doppler ultrasound was repeated six months later, addressing the same characteristics, and the collected data were compared. Results: Of 49 investigated patients, 32 (65.3%) were male (mean age=59.46 years). PSV, EDV, and ICA/CCA ratios showed no statistically significant difference 6 months following the completion of radiotherapy compared to the initial investigation. On the other hand, the percentage of carotid artery stenosis, the middle intimal membrane thickness, and the number of vascular plaques increased significantly (P<0.05). Conclusion: Carotid artery stenosis due to radiotherapy seems to be a common complication; however, radiotherapy probably has minimal effects on other ultrasound parameters of carotid arteries including EDV, PSV, and ICA/CCA ratio.

Prevalence of Carotid Artery Stenosis in Patients with Acute Myocardial Infarction Admitted to a Coronary Care Unit and its Relationship with Coronary Angiographic Findings

Objectives: The prevalence and clinical significance of carotid artery stenosis (CAS) in acute myocardial infarction (AMI) patients remain uncertain. This study aims to evaluate CAS prevalence and its association with coronary artery disease (CAD) severity in AMI patients admitted to a coronary care unit (CCU). Methodology: In this cross-sectional study, 100 consecutively selected AMI patients underwent ultrasound Doppler carotid artery assessments, including measurements of carotid intima-media thickness (cIMT), identification of plaque (stenosis >0%), and calculation of internal carotid artery/common carotid artery (ICA/CCA) peak systolic velocity ratio. Angiographic findings, including the number of diseased vessels and Syntax score (SS), were also recorded. Results: Among the study cohort (mean age 55.1±11.2 years, 78 males), 32 patients exhibited CAS, with 8 having cIMT>1.2mm, 3 showing ICA/CCA PSV ratio>2, and 25 presenting plaque. CAS prevalence did not significantly correlate with CAD severity, regardless of the number of diseased vessels or SS. Similarly, CAS rates did not significantly differ based on SS categories (low, intermediate, high). While CAS prevalence trended higher in patients with conventional atherosclerotic risk factors (diabetes, hypertension, smoking, obesity), these associations were not statistically significant. Conclusion: CAS was prevalent in approximately one-third of AMI patients, yet it did not demonstrate a significant association with CAD severity or SS. However, CAS rates tended to increase with the presence of conventional atherosclerotic risk factors. Further research is warranted to elucidate the clinical implications of CAS in AMI patients and its relationship with CAD severity.

From surgical clamping to endovascular flow arrest/reversal: the concept behind the system.

Carotid artery lesions are frequently composed of friable, thrombotic, ulcerated and/or hemorrhagic materials which can embolize during surgical or endovascular interventions. The use of embolic protection devices (EPD) during carotid angioplasty and stenting (CAS) has been proven to be associated with a reduction of the embolic load. Many studies indicate that the clinical results of CAS are comparable with the best surgical series, when EPD are routinely applied. The proximal EPD work by interrupting or reversing the blood flow in the common carotid artery/internal carotid artery (CCA/ICA). Once established the endovascular flow arrest/reversal, these systems have the advantages of promoting a protected crossing of the lesion and blocking both macro-emboli and micro-emboli. Moreover, proximal neuroprotection implies no manipulation of the device in the distal ICA, neither during device deployment nor during device retrieval, and reduces the risk of arterial spasm, dissection, or intimal damage. The choice between transfemoral and transcervical proximal EPD should account for different factors: local availability, operator expertise, and patient characteristics including anatomical features precluding flow arrest/reversal (e.g., incomplete circle of Willis), femoral access (e.g., unfavorable aortic arch anatomy), or transcervical access (e.g., diseased CCA).

Carotid Duplex Velocity Alterations Among Left Ventricular Assist Device Patients: Need for a Shift in Criteria?

Carotid duplex interpretation are based on velocity cutoffs and internal carotid artery/common carotid artery (ICA/CCA) ratios. Patients undergoing left ventricular assist device (LVAD) implantation pose a challenge in the standard interpretive criteria. The continuous flow produced by an LVAD alters normal pulsatile physiologic blood flow, lowering systolic flow and increasing diastolic flow. Therefore, we hypothesized that the presence of an LVAD alters the velocities observed on carotid artery duplex ultrasound examination, rendering traditional criteria difficult to interpret.

The Revised Sonographic NASCET Index: A New Hemodynamic Parameter for the Assessment of Internal Carotid Artery Stenosis.

A previously described Doppler parameter, the sonographic NASCET index (SNI), was derived to be more directly analogous to the North American Symptomatic Carotid Endarterectomy Trial (NASCET) methodology for assessing carotid artery stenosis. However, this index does not account for complex changes affecting the Doppler waveform. We propose a revised SNI (rSNI) in an effort to improve predicting carotid stenosis. 25 carotid bifurcations with stenoses ranging from 40 - 92 % were analyzed. For each vessel, the rSNI and original SNI were calculated. The peak systolic velocity (PSV), rSNI, and original SNI were correlated with angiography using linear regression analysis and relative accuracies were compared at two thresholds. A correlation between rSNI and angiography was found to be significantly better than that between PSV or internal carotid artery-common carotid artery (ICA-CCA) peak velocity ratio and angiography (r² = 0.47 vs. 0.22; r² = 0.47 vs. 0.16). The accuracy of PSV in predicting high-grade stenosis was 68% and 72%, compared with 80% and 88% for rSNI, at each of two thresholds. The original SNI better correlated with angiography compared to the rSNI (r² = 0.55 vs. 0.47), but with slightly lower accuracy in predicting high-grade stenosis (76% vs. 80%). The revised SNI correlates more closely with angiographic stenosis than either the PSV or the ICA-CCA ratio, and is more accurate in predicting high-grade stenosis. However, it is overall comparable to the original SNI, suggesting that the previously unaccounted for effects over the remainder of the cardiac cycle do not significantly improve the ability to sonographically predict significant stenosis.

Interprocedural Comparison of Changes in Natural Flow Velocity Patterns in the Internal Carotid Artery Following CAS or CEA

Different flow velocities have been reported after carotid angioplasty with stenting (CAS) than after carotid endarterectomy (CEA). We compared blood flow velocities following CAS and CEA in the International Carotid Stenting Study (ICSS; ISRCTN25337470). In total, 254 patients (70% male; 129 CAS and 125 CEA) were included. Mean peak systolic velocities (PSVICA) were assessed at baseline, 30 days, 1 and 2 years. Following both treatments, restenosis ≥ 50% was defined as PSVmean >125 cm s(-1). CAS and CEA resulted in a similar reduction in PSVICA 1 month after treatment. Post-intervention analysis for each treatment separately revealed that PSVICA following CAS increased significantly during follow-up (30 days to 2 years; 22.4 cm s(-1); 95% confidence interval (CI), 14.3 to 30.5). On the contrary, PSVICA following CEA remained relatively stable during follow-up (4.7 cm s(-1); 95% CI, -6.5 to 15.9). When we analysed the increase in PSVICA between both treatments after 2 years of follow-up, no significant interprocedural difference was observed. The internal carotid artery/common carotid artery (ICA/CCA) PSV ratio increased after CAS but not after CEA: 1.2 vs. 1.1 (0.04, 95% CI; -0.16 to 0.25) at 30 days; 1.5 vs. 1.1 (0.39, 95% CI; 0.13 to 0.65) at 1 year; and 1.5 vs. 1.1 (0.36; 95% CI, 0.08 to 0.63) at 2 years. The rate of apparent ipsilateral ICA restenosis >50% was higher following CAS (hazard ratio 2.35; 95% CI, 1.35 to 4.09). Two years after carotid revascularisation, no significant interprocedural difference was observed in the increase of PSVICA between CAS and CEA. However, the ICA/CCA ratio increased more following CAS resulting in an apparent higher rate of restenosis following CAS.

NITINOL STENTS

Stents deployed in the carotid arteries cause significant geometric changes in the vessels, influencing the flexibility and torsion characteristics of the vessels, which are aggravated by the high degree of mobility in this area of the body. The influence of these physical characteristics on carotid blood flow could influence the long term performance of the deployed stents. Objectives: To evaluate the geometric changes in the carotid arteries after deployment of self expanding nitinol stents. Settings: AFIC-NIHD. Period: November 2003 to August 2008. Material & methods: 45 cases of carotid artery stenting (CAS) done. We selected cases where the stenting to the internal carotid artery (ICA) had been done across the bifurcation of the common carotid artery (CCA) with self expanding nitinol stents, and when DICOM videos that had pre and post stenting images in the same imaging projection were available for analysis. Based on the inclusion criteria 21 videos were selected and deemed fit for taking measurements. The measurement system proposed by Berkefeld et al which involved the measurement of the CCA-ICA (common carotid artery –internal carotid artery) angle and ICA-offset was used. These variables were measured using onscreen measuring software which can measure linear distances and angles after appropriate calibration for each image. Results: We did not find any significant changes in the ICA-offset; significant changes in the CCA-ICA angle were noted.

Duplex criteria for determining ≥50% and ≥80% internal carotid artery stenosis following carotid endarterectomy with patch angioplasty

The purpose of this study was to determine optimal velocities for detecting ≥50% and ≥80% restenosis prior to considering carotid intervention/carotid artery stenting (CAS) after carotid endarterectomy (CEA) with patching in symptomatic and asymptomatic patients. Two hundred CEA patients with 195 pairs of imaging (duplex ultrasound versus computed tomography angiography [CTA]/carotid arteriography) were analyzed. Peak systolic velocities (PSVs), end diastolic velocity (EDV) and internal carotid artery/common carotid artery (ICA/CCA) ratios were correlated to angiography. Receiver operator characteristic (ROC) curves determined optimal velocity criteria in detecting ≥50% and ≥80% restenosis. The mean PSVs for ≥50% and ≥80% restenosis were 248 and 404 c/s, respectively (P < 0.001). A PSV of ≥213 c/s was optimal for ≥50% restenosis with sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and overall accuracy (OA) of 99%, 100%, 100%, 98% and 99%, respectively. An ICA PSV of 274 c/s was optimal for ≥80% restenosis with sensitivity, specificity, PPV, NPV and OA of 100%, 91%, 99%, 100% and 99%, respectively. ROC analysis showed that PSVs were significantly better than EDVs and ICA/CCA ratios in detecting ≥50% restenosis. Standard duplex velocity criteria should be revised after CEA using patching. Specific carotid duplex velocities can be used to detect ≥50% and ≥80% restenosis after CEA with patch closure prior to carotid intervention/CAS.

Proposed duplex velocity criteria for carotid restenosis following carotid endarterectomy with patch closure

Duplex ultrasound velocity criteria have been used to evaluate the severity of carotid stenosis, however, these standard velocities may not be applicable to carotid restenosis after carotid endarterectomy (CEA) with patch angioplasty. The purpose of this study is to determine if patch angioplasty closure alters velocities just distal to CEA and to define the optimal velocities for detecting >or=30%, >or=50%, and >or=70% restenosis. This study includes 200 CEAs randomized into 100 with polytetrafluoroethylene (PTFE) ACUSEAL patch and 100 with Hemashield Finesse patch. All patients underwent immediate postoperative duplex ultrasounds, which were repeated at 1 month and every 6 months thereafter. Patients with a peak systolic velocity (PSV) of the internal carotid artery ([ICA], just distal to the patch) of >or=130 c/s underwent computed tomography angiogram (CTA). PSVs, end diastolic velocities (EDV), and internal carotid artery/common carotid artery (ICA/CCA) ratios were correlated to completion arteriograms/CTAs. Receiver operator characteristic curves analyses were used to determine optimal velocity criteria in detecting >or=30%, >or=50%, and >or=70% restenosis. One hundred ninety-five pairs of imagings (duplex ultrasound vs CTA/angiogram) were available for analysis. When standard velocity criteria for nonoperated arteries were applied, 37% and 10% of patients were believed to have >or=50% to <70% and >or=70% to 99% restenosis vs 11.3% and 11.3% on CTA/angiography, respectively (P < .001). The mean PSV for >or=30%, >or=50%, and >or=70% restenosis were 172, 249, and 389 c/s, respectively (P < .001). An ICA PSV of >or=155c/s was optimal for >or=30% restenosis with sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy (OA) of 98%, 98%, 98%, 98%, and 98%, respectively. A PSV of >or=213 c/s was optimal for >or=50% restenosis with sensitivity, specificity, PPV, NPV, and OA of 99%, 100%, 100%, 98%, and 99%, respectively. An ICA PSV of 274 c/s was optimal for >or=70% restenosis with sensitivity, specificity, PPV, NPV, and OA of 99%, 91%, 99%, 91%, and 98%, respectively. ROC analysis showed that the PSVs were significantly better than EDVs and ICA/CCA ratios in detecting >or=30% and >or=50% restenosis. The mean PSVs of a normal ICA distal to CEA patching were higher than normal nonoperated ICAs, therefore, standard duplex velocities criteria should be revised after CEA with patch closure.

Open-cell versus closed-cell stent design differences in blood flow velocities after carotid stenting

The differential effect of open-cell vs closed-cell stent design configuration on carotid velocities detected by duplex ultrasound (DUS) imaging has not been established. To identify possible stent design differences in carotid velocities, we analyzed DUS studies obtained before and immediately after carotid artery stenting (CAS). In a series of 141 CAS procedures performed during a 3-year period, data from the first postinterventional DUS images and carotid angiograms were evaluated for each patient. Peak systolic velocities (PSV), end-diastolic velocities (EDV), and internal carotid artery/common carotid artery (ICA/CCA) PSV ratios were compared according to stent design. Differences in carotid velocities were analyzed using nonparametric statistical tests. Completion angiograms revealed successful revascularization and <30% residual stenosis in each case. The 30-day stroke-death rate in this series was 1.6% and was unrelated to stent type. Postintervention DUS images were obtained a median of 5 days (interquartile range [IQR], 1-25 days) after CAS. Closed-cell stents were used in 41 procedures (29%) and open-cell stents in 100 (71%). The median PSV was 95.9 cm/s (IQR, 77-123 cm/s) for open-cell stents and 122 cm/s (IQR, 89-143 cm/s) for closed-cell stents, which was significantly higher (P = .007). Closed-cell stents also had significantly higher median EDVs (36 vs 29 cm/s; P =.006) and ICA/CCA PSV ratios (1.6 vs 1.1; P =.017). By DUS criteria, the carotid velocities in 45% of closed-cell stents exceeded the threshold of 50% stenosis for a nonstented artery compared with 26% of open-cell stents (P =.04). Closed-cell stents had a 2.2-fold increased risk of yielding abnormally elevated carotid velocities after CAS compared with open-cell stents (odds ratio, 2.2; 95% confidence interval, 1.02-4.9). Carotid velocities are disproportionately elevated after CAS with closed-cell stents compared with open-cell stents. This suggests that the velocity criteria for quantifying stenosis may require modification according to stent design. The importance of these differences in carotid velocities related to stent design and the potential relationship with recurrent stenosis remains to be established.

Results using a self-expanding stent alone in the treatment of severe symptomatic carotid bifurcation stenosis

Conventional endovascular therapy for carotid stenosis involves placement of an embolic protection device followed by stent insertion and angioplasty. A simpler approach may be placement of a stent alone. The authors determined how often this approach could be used to treat patients with carotid stenosis, and assessed which factors would preclude this approach. Over a period of 6 years, 97 patients with symptomatic carotid stenosis were treated with the intention of using a "stent-only" approach. Arteries in 77 patients (79%) were treated with stents alone, 13 required preinsertion balloon dilation, 6 postinsertion dilation, and 1 both pre- and postinsertion dilation. The mean stenosis according to North American Symptomatic Carotid Endarterectomy Trial criteria was reduced from 82 to 40% in the stent-only group and from 89 to 37% in the stent and balloon angioplasty group. The 30-day stroke and death rate was 7.2%. Patients were followed for a mean of 15 months. In the stent-alone group, the mean preoperative Doppler peak systolic velocity (PSV) was 409 cm/second, with an internal carotid artery/common carotid artery (ICA/CCA) ratio of 7.2. At follow-up review, the PSV decreased to 153 cm/second and the ICA/CCA ratio to 2.1. In the angioplasty group the mean preoperative PSV was 496 cm/second and the ICA/CCA ratio was 9.2, decreasing to 163 cm/second and 2, respectfully, at follow-up evaluation. Restenosis occurred in 12.8% of patients at 6 months and in 15.9% at 1 year. One stroke occurred during the follow-up period in each group. Using multivariable analysis, factors precluding the "stent-only" approach were as follows: severity of stenosis, circumferential calcification, and no history of hyperlipidemia. Balloons may not be required to treat all patients with carotid stenosis. A stent alone was feasible in 79% of patients, and 79% of patients were alive and free from ipsilateral stroke or restenosis at 1 year. Restenosis rates with this approach are higher than with conventional angioplasty and stent insertion. Carotid arteries with very severe stenoses (> 90%) and circumferential calcification may be more successfully treated with angioplasty combined with stent placement.

Postcarotid Endarterectomy Pseudoaneurysm Treated with Combined Stent Graft and Coil Embolization

Pseudoaneurysm formation is a rare complication following carotid endarterectomy (CEA); however, its occurrence is associated with significant risk of morbidity. The patient in this report presented 2 years following CEA with headache and lateral neck mass. The diagnosis of a 3.5 x 3.0 cm carotid artery bifurcation pseudoaneurysm was made by using magnetic resonance angiography (MRA). Endovascular exclusion of the aneurysm was accomplished with coil embolization of the external carotid artery followed by deployment of a 7 x 50 mm wall stent graft into the common carotid artery-internal carotid artery (CCA-ICA). The patient's symptoms improved and at 6-months postexclusion, duplex ultrasound demonstrated a significant reduction in pseudoaneurysm size. This case highlights the feasibility and safety of using endovascular techniques in the treatment of post-CEA pseudoaneurysm.

Effect of contralateral disease on duplex measurements of internal carotid artery stenosis.

Duplex ultrasonography is increasingly used as the sole method of imaging before carotid endarterectomy. This study investigated the measured degree of stenosis in the contralateral carotid artery before and after operation. Duplex-derived peak systolic velocity (PSV), end-diastolic velocity (EDV) and internal carotid artery/common carotid artery (ICA/CCA) velocity ratios were measured in the contralateral unoperated ICA before 131 consecutive unilateral endarterectomies and compared with preoperative angiographic findings. Three months later duplex scans were repeated to assess whether there had been any alteration in the severity of the stenosis in the contralateral unoperated artery. Bilateral ICA disease (greater than 50 per cent stenosis) was present in 50 patients (38 per cent). Three months after operation, ultrasonography of the 105 unoperated, patent, contralateral arteries showed a decrease in mean(s.d.) PSV (1.21(0. 83) versus 1.07(0.69) m/s; P < 0.01) and EDV (0.41(0.29) versus 0. 35(0.24) m/s; P < 0.01). This resulted in 14 (42 per cent) of 33 patients with contralateral disease being downgraded to a less severe category of stenosis. Use of the ICA/CCA velocity ratio prevented overestimation in eight of the 14 patients, while preoperative angiography correctly classified 13 of the 14 patients. Bilateral carotid artery disease can cause overestimation of the severity of stenosis by duplex ultrasonography if absolute velocity is used as the main criterion.