Usefulness of acceleration time for internal carotid artery origin stenosis

Duplex Ultrasonography-Based Comparative Analysis of Inner Branch Orientation for the Left Common Carotid Artery following Triple-Branch Arch Endovascular Repair

OBJECTIVE

The purpose of this study was to evaluate left common carotid artery (LCCA) perfusion using duplex ultrasonography (DUS) after endovascular repair of the aortic arch (endoarch) with a triple-branch arch device, featuring either an anterograde or retrograde inner branch configuration for the LCCA.

METHODS

Patients who underwent branched endoarch repair from May 2020 to February 2025 were identified using a prospectively maintained electronic database at a single, tertiary-care hospital. Inclusion criteria included implantation of the triple-branch arch device (Cook Medical) with an anterograde inner branch for the brachiocephalic trunk (BCT), an anterograde or retrograde inner branch for the LCCA, and a retrograde branch for the left subclavian artery (LSA). Exclusion criteria included no follow-up and postoperative DUS. Patient demographics, comorbidities, indication for the procedure, procedural details, and outcomes were recorded. The cohort was dichotomized based on LCCA branch orientation. The primary outcomes were to define postoperative DUS-based perfusion metrics of the bilateral carotid arteries and to compare them based on the orientation of the LCCA branch. The right common carotid artery (RCCA) served as a control, as it featured only an anterograde branch for the BCT. The secondary outcomes were to compare inner branch primary patency, stroke-related outcomes, reintervention, and mortality.

RESULTS

A total of 74 patients underwent endoarch repair with the triple-branch arch device during the study period, of which 39 met the study inclusion criteria, with 18 (46%) anterograde and 21 (54%) retrograde inner branches of the LCCA. Most patients were male (74%) with a median age of 72 years. There was a high incidence of hypertension (90%) and dyslipidemia (59%). The indication for repair was a degenerative (51%) or chronic post-dissection (49%) aortic arch aneurysm. A totally percutaneous approach for procedural access occurred in 71% of the retrograde group (vs 17% anterograde). There was a decreased median operating time for LCCA retrograde branch of 160 min (vs 218 min anterograde). Thirty-day stroke was 5% (n=2, both anterograde), with no mortality. Postoperative DUS demonstrated similar perfusion metrics between the experimental LCCA and the control RCCA, regardless of the orientation of the LCCA inner branch. In the retrograde group, both the RCCA and LCCA featured predominantly monophasic (62%) and triphasic (31%) waveforms; the median peak systolic velocity (PSV), end diastolic velocity (EDV), and acceleration time (AcT) were 64-68 cm/s, 17-21 cm/s, and 56-65 ms, respectively. Midterm (median follow-up 11 months) outcomes were notable for 1 mortality, without events of stroke or target vessel-related reinterventions.

CONCLUSIONS

In endoarch repair with the triple branch device, inner branch orientation yields no significant difference in DUS-based perfusion metrics of both carotid arteries. In the retrograde orientation of the LCCA inner branch, there was decreased operative time with increased rates of a totally percutaneous approach, without increased incidence of stroke or reintervention. This retrospective study further supports the device modification from the anterograde to retrograde orientation of the LCCA inner branch in favorable anatomies.

Usefulness of "AcT ratio" in diagnosis of internal carotid artery stenosis: a multicenter, retrospective, observational study

PURPOSE

The ratio of the internal carotid artery (ICA) to the common carotid artery (CCA), especially the "AcT ratio," which is a modified measurement method of acceleration time, is useful for diagnosing ICA-origin stenosis. However, previous studies were single-center studies. Therefore, this multicenter, retrospective, cross-sectional study aimed to determine whether a method using the AcT ratio is useful for estimating stenosis rates.

METHODS

This study included 461 vessels subjected to carotid artery ultrasonography and evaluation for ICA-origin stenosis via NASCET at four hospitals. The duration from the steep rise point to the inflection point or the first peak was defined as AcT on pulsed wave Doppler. The AcT ratio was calculated as AcT of ICA/AcT of ipsilateral CCA. The AcT ratio and rate of ICA-origin stenosis were analyzed using Pearson's correlation coefficient, simple regression analysis, and ROC curve.

RESULTS

A significant positive correlation was observed between the AcT ratio and NASCET stenosis. NASCET stenosis of ≥ 50% had a sensitivity, specificity, and negative predictive value (NPV) of 70.2%, 71.6%, and 91.5%, respectively, when the cut-off value of the AcT ratio was 1.17. NASCET stenosis of ≥ 70% had a sensitivity, specificity, and NPV of 70.5%, 72.1%, and 95.9%, respectively, when the cut-off value of the AcT ratio was 1.22.

CONCLUSIONS

The findings of this multicenter, retrospective, cross-sectional study suggest that the AcT ratio is useful for diagnosing ICA-origin stenosis, especially for diagnosis by exclusion. NASCET stenosis of ≥ 50% was considered unlikely if the Act ratio was ≤ 1.17, whereas NASCET stenosis of ≥ 70% was considered unlikely if it was ≤ 1.22.

Waveform parameters of retrobulbar vessels in glaucoma patients with different demographics and disease severity

Introduction:

To identify novel velocity waveform parameters of the ophthalmic artery and central retinal artery by computer-aided image processing of Doppler ultrasonography measurements, and to evaluate correlations between the waveform parameters and different demographics and disease severity of open-angle glaucoma patients.

Methods:

Thirty-six images of 36 open-angle glaucoma patients were considered. A semiautomated image processing code was used to detect the digitalized ophthalmic artery and central retinal artery velocity waveforms and to extract the waveform parameters. Concordance correlation coefficient, two-sample t-test, and Pearson’s correlation coefficient were used to test for similarities, differences, and associations among variables.

Results:

Female glaucoma patients showed a statistically higher ophthalmic artery normalized distance between ascending and descending limb (p = 0.004), hypertensive glaucoma patients a statistically higher ophthalmic artery peak systolic velocity time (p = 0.025), glaucoma patients with hyperlipidemia a statistically higher ophthalmic artery resistivity index (p = 0.023) and a statistically higher ophthalmic artery peak systolic velocity acceleration (p = 0.025), glaucoma patients with cardiovascular diseases a statistically lower central retinal artery normalized distance between ascending and descending limb of the wave (p = 0.033) and a statistically higher central retinal artery period (p = 0.028), and patients with different body mass index a statistically different central retinal artery normalized distance between ascending and descending limb of the wave (p = 0.016). Groups with different disease severity, classified following the Brusini glaucoma staging system 2, showed statistically different central retinal artery normalized distance between ascending and descending limb of the wave (p < 0.001) and central retinal artery period (p = 0.016). No statistical differences were found in regard to race, diabetes status, glaucoma family history, and smoking.

Discussion:

Ophthalmic artery and central retinal artery computer-aided analysis of velocity waveforms could identify novel waveform parameters capable of differentiating among different demographics and disease severity of open-angle glaucoma patients.

Suitable methods of measuring acceleration time in the diagnosis of internal carotid artery stenosis

Purpose

To enhance the utility of acceleration time (AcT) in the diagnosis of internal carotid artery (ICA) stenosis, we assessed the value of AcT measurements with different waveform patterns.

Methods

Ninety-three patients with acute atherothrombotic cerebral infarction were enrolled, and they underwent both carotid ultrasonography and digital subtraction angiography (DSA). AcT was determined by a conventional procedure (using the first peak point or the bending point) and the peak systolic velocity (PSV) procedure. The AcT ratio was calculated as (AcT of ICA)/(AcT of the ipsilateral common carotid artery). We evaluated the correlation of stenosis rate as assessed by the North American Symptomatic Carotid Endarterectomy Trial method using DSA (DSA-NASCET) with the AcT of ICA (ICA-AcT), the AcT ratio measured by the conventional procedure (conventional AcT ratio), and the AcT ratio measured by the PSV procedure (PSV AcT ratio). The area under receiver operating characteristic curves (AUC) for DSA-NASCET was calculated based on the ICA-AcT and AcT ratio.

Results

Forty-five vessels had 50% or greater ICA stenosis. DSA-NASCET was positively correlated with the conventional AcT ratio (r = 0.723), conventional ICA-AcT (r = 0.638), and PSV AcT ratio (r = 0.245). The corresponding AUCs for ICA stenosis ≥ 50% were 0.971, 0.886, and 0.572, respectively.

Conclusion

We demonstrated the usefulness of the conventional procedure for diagnosing stenosis of ICA origin using AcT and showed that the AcT ratio was a more beneficial parameter than AcT.

Assessment of carotid artery ultrasonography in the presence of an acoustic shadow artifact

Background

B-mode and Color Doppler ultrasonography (CDUS) are the methods of choice for screening and determining the degree of Carotid artery stenosis. The evaluation of stenosis with calcification may be hampered by a common CDUS artifact known as acoustic shadow (AS). Our objective was to assess the change in reliability of CDUS readings in the presence of an AS artifact.

Methods

Single center retrospective observational study. Included were patients with either an AS artifact or high-grade stenosis (defined by peak systolic velocity (PSV) > 240 cm/s) demonstrated in CDUS, and had a CT angiography (CTA) done within 6 months of the sonographic exam. All subjects were identified through the Tel-Aviv Sorasky medical center (TASMC) CDUS unit registry from which clinical information was extracted. CDUS images were manually reviewed grading AS magnitude. All CTAs were reviewed and reconstructed for accurate assessment of percent stenosis and were used as gold standard.

Results

The study cohort included 227 consecutive patients (corresponding with 454 internal carotid arteries) meeting inclusion criteria. 43.2% of the arteries (n = 195) had an AS artifact present on CDUS, regardless of percent stenosis, with a large artifact present in 6.7% arteries (n = 30). Older age was significantly related to the presence of AS artifact (p < 0.001). In the study cohort as a whole there was a strong correlation between percent stenosis on CTA and PSV values (Pearson’s r 0.672, p < 0.001) regardless of AS existence. The CDUS sensitivity and specificity for predicting severe stenosis were 82 and 73% respectively. The presence of a small AS slightly diminished the correlation between CDUS and CTA results without compromising CDUS reliability. A large AS severely affected the correlation between CDUS and CTA exams (Pearson’s r = 0.24, p = 0.27) and reduced CDUS reliability with a sensitivity and specificity of 62%.

Conclusion

The presence of a large AS severely degrades the accuracy of the routine CDUS measurements. In these cases, the patient should be referred to a CDUS exam including doppler-measurement of periorbital arteries and intracranial arteries in addition to other imaging modalities such as CTA or MRA in order to assess future stroke risk.

Peak Systolic Velocity for Calcified Plaques Fails to Estimate Carotid Stenosis Degree

BACKGROUND

Duplex ultrasonography (DUS), although consolidated as the primary tool for the estimation of carotid stenosis, may be impaired by calcified plaques that promote acoustic shadow (AcS). AcS seems to hamper the quantification of the main parameter used in the determination of percentage stenosis, that is, the maximal peak systolic velocity (PSV) at the lesion site. The aim of our study was to compare the degrees of carotid artery stenosis in DUS/PSV and computed tomography angiography (CTA) in the presence of AcS.

METHODS

During 36 months, 1,178 carotid DUS tests were performed. A total of 164 carotids in 139 patients showed AcS resulting from calcified plaques. Carotids with AcS were referred for a second imaging examination; thus, 62 carotids were analyzed by both DUS/PSV and CTA. CTA measured the area reduction at the lesion site to calculate the percent stenosis. PSV was measured immediately after the end of the AcS. According to velocities-based DUS criteria, stenoses were classified as mild (PSV < 125 cm/s), moderate (125 ≤ PSV ≤ 230 cm/s), and severe (PSV > 230). CTA and DUS/PSV measurements were compared to determine the accuracy of PSV in characterizing the severity of carotid stenosis with AcS.

RESULTS

Of the 62 lesions, PSV characterized 10 as severe, 21 as moderate, and 31 as mild. According to the CTA study, there were 36 severe, 8 moderate, and 18 mild lesions. PSV underestimated in 27.79% the incidence of cases of severe carotid artery stenosis detected by the CTA. In addition, PSV overestimated the incidence of the cases of moderate and mild stenosis in 61.91% and 37.78%, respectively. The agreement ratio between the imaging examinations used in this study was 50%. DUS/PSV discretely correlated with CTA (r = 0.668, P < 0.0001, 95% confidence interval = 0.502-0.786). Using PSVs >125 and >230 as predictors of carotid lesions higher than 50% and 70%, respectively, the sensitivities were 63.3% and 27.8%, the specificities were 100%, the positive predictive values were 100%, and the negative predictive values were 71.9% and 50%.

CONCLUSION

PSV alone is inadequate to quantify carotid stenosis in the presence of calcified plaques and AcS. Another image tool, such as CTA, could be recommendable for clinical decision-making.

Usefulness of acceleration time ratio in diagnosis of internal carotid artery origin stenosis

Purpose

The acceleration time (AcT) ratio of the internal carotid artery (ICA) is increased in ICA stenosis. However, there are few reports that have directly compared the AcT ratio to digital subtraction angiography (DSA) findings.

Methods

We evaluated 177 vessels with DSA and carotid artery ultrasonography. The AcT ratio was calculated as AcT of the ICA (ICA–AcT)/AcT of the ipsilateral common carotid artery (CCA). We evaluated the correlation of DSA–NASCET stenosis with the origin of the ICA or the peak systolic velocity (ICApsv) in the stenotic region, ICApsv/peak systolic velocity of the CCA (CCApsv), ICA–AcT, and AcT ratio. Sensitivity and specificity for stenosis ≥ 70% were calculated based on the ICApsv, ICApsv/CCApsv, ICA–AcT, and AcT ratio.

Results

Using NASCET criteria, 34 vessels had 70% or greater stenosis. DSA–NASCET showed a significant positive correlation with ICApsv, ICApsv/CCApsv, ICA–AcT, and AcT ratio (p < 0.0001). When the cut-off value for ICApsv was set at 176 cm/s, ICApsv/CCApsv at 2.42, ICA–AcT at 0.095 s, and the AcT ratio at 1.35, the sensitivity was 97.1, 97.1, 82.4, and 97.1%, and the specificity was 94.4, 91.0, 83.2, and 83.2%, for DSA–NASCET ≥ 70%, respectively.

Conclusion

The AcT ratio is a beneficial parameter for evaluating ICA stenosis as well as ICApsv and ICApsv/CCApsv.

Common carotid artery end-diastolic velocity and acceleration time can predict degree of internal carotid artery stenosis

OBJECTIVE

Whereas duplex ultrasound parameters for predicting internal carotid artery (ICA) stenosis are well defined, the use of common carotid artery (CCA) Doppler characteristics to predict ICA stenosis when the ICA cannot be insonated directly or accurately because of anatomy, calcification, or tortuosity has not been studied. The objective of this study was to identify CCA Doppler parameters that may predict ICA stenosis.

METHODS

We reviewed all patients at our institution who underwent carotid duplex ultrasound (CDU) from 2008 to 2015 and also had a comparison computed tomography, magnetic resonance, or catheter angiogram. We excluded patients whose CDU examination did not correlate with the comparison study, those whose arteries were not visualized on the comparison study, and those with complete occlusion of the CCA. We collected CCA peak systolic velocity (PSV), end-diastolic velocity (EDV), and acceleration time (AT) in addition to CDU and comparison imaging interpretation of degree of stenosis. A multivariate model was used to identify predictors of ICA stenosis.

RESULTS

There were 99 CDU examinations with corresponding comparison imaging included. For every increase of 10 cm/s in EDV in the CCA, the odds of a >50% ICA stenosis being present vs a ≤50% ICA stenosis decreased by 37% (odds ratio [OR], 0.63; 95% confidence interval [CI], 0.41-0.97; P = .03). For every increase of 10 cm/s in EDV in the CCA, the odds of a 70% to 99% ICA stenosis being present vs a ≤50% ICA stenosis decreased by 48% (OR, 0.52; 95% CI, 0.28-0.94; P = .03). A CCA EDV of 19 cm/s or below was associated with a 64% probability of a 70% to 99% ICA stenosis. For every 50-millisecond increase in AT in the CCA, the odds of a >50% stenosis being present vs a ≤50% ICA stenosis increased by 56% (OR, 1.56; 95% CI, 1.03-2.35; P = .04). A CCA AT of 80 milliseconds or above was associated with a 69% probability of a >50% ICA stenosis. There was no correlation between CCA PSV and ICA stenosis.

CONCLUSIONS

CCA EDV and AT are independent predictors of ICA stenosis and may be used in the setting of patients whose ICA cannot be directly insonated or when standard duplex ultrasound parameters of ICA PSV, EDV, or ICA/CCA ratio conflict.

Acoustic shadowing impairs accurate characterization of stenosis in carotid ultrasound examinations

OBJECTIVE

Duplex ultrasonography (DUS) has been the mainstay for diagnosing carotid artery stenosis and is often the sole diagnostic modality used prior to intervention. Highly calcified plaque, however, results in an acoustic shadow (AcS) that obscures the vessel lumen and inhibits the sonographer's ability to obtain Doppler velocity measurements. It is unknown whether DUS can accurately determine the degree of carotid stenosis in these settings.

METHODS

From July 2012 to December 2013, all patients with AcS on DUS measuring ≥5 mm in the longitudinal axis were cross-referenced with multidetector computed tomographic angiography (MD-CTA) images of the neck to define the study population. After standardizing the MD-CTA windows, percent stenosis was determined by cross-sectional area reduction using two separate previously described methods based on North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST) criteria. DUS waveform parameters in the internal carotid artery near the AcS were then compared with these MD-CTA measurements to determine the accuracy of DUS in characterizing the severity of carotid stenosis.

RESULTS

During this period, 8517 DUS studies were performed at the Massachusetts General Hospital, 550 of which had AcS, for an incidence of 6.45%. There were 92 lesions with a concomitant MD-CTA; however, seven were excluded because of poor study quality, because ≥6 months had elapsed between DUS and MD-CTA, or because the patient had undergone carotid reconstruction between studies. Of the 85 remaining lesions, DUS characterized 17 as severe (peak systolic velocity [PSV] >250 cm/s), 31 as moderate (PSV = 151-250 cm/s), and 37 as mild (PSV ≤150 cm/s) stenoses using PSV criteria. PSV weakly correlated with CTA-NASCET (r = 0.361; P = .004) and CTA-ECST (r = 0.306; P = .004) percent stenosis. Using PSV >250 cm/s as the predictor of >70% stenosis, and a ≥70% cutoff by both CTA-ECST and CTA-NASCET methods as the reference measure, DUS sensitivity ranged from 22.7% to 32.5%, specificity from 89.4% to 91.1%, positive predictive value from 88.2% to 76.4%, and negative predictive value from 25% to 60.2%. A subgroup analysis of lesions identified as non-severe by DUS revealed that waveforms with lower deceleration were associated with severe stenosis on CTA.

CONCLUSIONS

In the presence of AcS, DUS alone is inadequate to accurately determine the degree of carotid stenosis with sensitivity, specificity, and negative predictive values far below that needed for clinical decision-making. MD-CTA may be necessary for improved characterization of plaque in these AcS lesions. Further studies are needed to determine DUS parameters that may identify patients who should undergo further evaluation with MD-CTA to characterize the true severity of the stenosis.