Carotid revascularization: risks and benefits

The intracranial effects of flow reversal during transcarotid artery revascularization

Background

This study aimed to assess intraoperative cerebral hemodynamic responses and embolic events during transcarotid artery revascularization via transcranial Doppler, near-infrared spectroscopy, and bispectral index monitoring.

Methods

Twelve patients (7 males, 5 females; mean age: 72.8±9.0 years; range, 63 to 91 years) undergoing transcarotid artery revascularization with simultaneous transcranial Doppler, near-infrared spectroscopy, and bispectral index monitoring were analyzed in this retrospective study between September 2017 and December 2019. The mean flow velocity and pulsatility index of the middle cerebral artery, alongside near-infrared spectroscopy and bispectral index values, before flow reversal, during flow reversal, and after flow reversal phases were investigated. The presence and frequency of high-intensity transient signals were recorded to evaluate embolic incidents.

Results

Significant reductions in middle cerebral artery mean flow velocity were noted during flow reversal (40.58±10.57 cm/sec to 20.58±14.34 cm/sec, p=0.0004), which subsequently returned to and exceeded baseline values after flow reversal cessation (53.33±17.69 cm/sec, p=0.0005). Near-infrared spectroscopy (71±4.4% to 66±6.2%) and bispectral index (45.71±8.5 to 40.14±8.1) values mirrored these hemodynamic changes, with notable decreases during flow reversal, and recoveries after flow reversal. The highest concentration of high-intensity transient signals was observed during stent deployment, signifying a critical embolic phase. No perioperative neurological complications or other significant adverse events were documented.

Conclusion

Transcranial Doppler, near-infrared spectroscopy, and bispectral index effectively monitor cerebral hemodynamics and embolic potential during transcarotid artery revascularization, providing real-time data crucial for optimizing perioperative management. These findings underscore the clinical value of multimodal monitoring in improving patient outcomes in transcarotid artery revascularization procedures.

Aberrant expression of miR-483-5p in patients with asymptomatic carotid artery stenosis and its predictive value for cerebrovascular event occurrence

MicroRNAs (miRNAs/miRs) may be used as novel promising diagnostic and prognostic biomarkers for various diseases, including asymptomatic carotid artery stenosis (ACAS). The present study aimed to investigate the abnormal expression of microRNA-483-5p (miR-483-5p) in patients with ACAS and to evaluate its diagnostic value for ACAS screening and its predictive value for cerebrovascular events. A total of 128 patients with ACAS and 76 healthy controls were included in the present study. The expression of miR-483-5p in serum was measured by reverse transcription-quantitative PCR. Receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic value of miR-483-5p in patients with ACAS. Kaplan-Meier curves were drawn and Cox regression analysis was used to determine the predictive value of miR-483-5p for cerebrovascular events in patients with ACAS. Serum miR-483-5p levels were significantly increased in patients with ACAS as compared with those in healthy controls. The expression of miR-483-5p was significantly associated with diabetes (P=0.011), dyslipidemia (P=0.047) and the degree of carotid stenosis (P=0.006) in patients with ACAS. In addition, the area under the ROC curve was 0.910, with a sensitivity of 80.5% and a specificity of 89.5% at the cutoff value of 0.705, indicating that serum miR-483-5p expression has a certain diagnostic value in patients with ACAS. Furthermore, the patients with high miR-483-5p expression had a higher proportion of cerebrovascular events than patients with low miR-483-5p levels (log-rank P=0.011) and miR-483-5p was an independent prognostic marker for predicting the occurrence of cerebrovascular events in patients with ACAS. The results indicated that miR-483-5p expression is significantly increased in patients with ACAS and that abnormal miR-483-5p expression may be a candidate biomarker for ACAS diagnosis and the prediction of cerebrovascular event occurrence.

Review of imaging biomarkers for the vulnerable carotid plaque

Identification of carotid artery atherosclerosis is conventionally based on measurements of luminal stenosis. However, histopathologic studies demonstrate considerable differences between plaques with identical degrees of stenosis and indicate that certain plaque features are associated with increased risk for ischemic events. As a result of the rapid technological evolution in medical imaging, several important steps have been taken in the field of carotid plaque imaging allowing us to visualize the carotid atherosclerotic plaque and its composition in great detail. For computed tomography, magnetic resonance imaging, positron emission tomography, and ultrasound scan, evidence has accumulated on novel imaging-based markers that confer information on carotid plaque vulnerability, such as intraplaque hemorrhage and lipid-rich necrotic cores. In terms of the imaging-based identification of individuals at high risk of stroke, routine assessments of such imaging markers are the way forward for improving current clinical practice. The current review highlights the main characteristics of the vulnerable plaque indicating their role in the etiology of ischemic stroke as identified by intensive plaque imaging.

[Comparative analysis of safety of carotid endarterectomy performed in acutest and acute periods of ischaemic stroke]

Surgical revascularization of the carotid basin in the acutest period of ischaemic stroke, i.e., within 72 hours, will make it possible to prevent the development of recurrent stroke by removing an embologenically dangerous atherosclerotic plaque of the symptomatic carotid artery and to improve cerebral blood supply, having eliminated haemodynamic stenosis of the carotid artery. However, the problem of safety of carotid endarterectomy in patients during the acutest period of ischaemic stroke still remains debatable.

PURPOSE

To comparatively analyse safety of eversion carotid endarterectomy performed in the acutest (0-72 hours) and acute (4-14 days) periods of minor ischaemic stroke.

PATIENTS AND METHODS

Between January 2015 and December 2019, specialists of the Department of Vascular Surgery of Municipal Clinical Hospital # 7 of Kazan performed a total of 80 eversion carotid reconstructions in the period of minor ischaemic stroke within 14 days. The patients were divided into 2 groups depending on the terms of performing carotid endarterectomy. The first group comprised 32 (40.0%) patients operated on in the acutest period of ischaemic stroke, i.e., within 72 hours from the onset of first symptoms of neurological deficit. The second group included 48 (60.0%) patients subjected to carotid endarterectomy within 4 to 14 days from the onset of first signs of neurological deficit.

RESULTS

According to the obtained findings, haemorrhagic transformation in the early postoperative period occured in 2 Group Two patients, with one lethal outcome on POD 3. Cerebral ischaemia increased in one patient of each group without enlargement of the ischaemic zone according to brain computed tomography, with residual neurological deficit in Group I in remote period (Rankin scale score 1) and complete restoration in Group II (Rankin scale score 0). Recurrent minor ischaemic stroke on POD 1 developed in Group II with formation of a new lacunar region of ischaemia of the brain in the operated carotid basin and was verified by the findings of cerebral MRI with persisting neurological deficit for 6 months (Rankin scale score 2). The comparative assessment of severity of stroke on the day of operation and at discharge, as well as that of neurological symptomatology during the 1st and 6th months of follow up in both groups proved positive. No events of acute coronary syndrome, recurrent strokes or lethal outcomes were observed during the follow-up period.

CONCLUSION

According to the findings of our study, patients with acute cerebral circulation impairment caused by embologenically dangerous lesions of internal carotid arteries should be operated on within the first 72 hours, if there are no accompanying changes requiring time for correction thereof.

Intravascular lithotripsy during transcarotid arterial revascularization for highly calcified lesions in high-risk patients

Transcarotid arterial revascularization (TCAR) with flow reversal offers a less invasive option for carotid revascularization in high-risk surgical patients. TCAR has been shown to have similar complication rates for stroke and mortality compared with carotid endarterectomy and lower complication rates compared with transfemoral carotid artery stenting. A relative contraindication for carotid stenting includes heavily calcified lesions. Intravascular lithotripsy has been approved for use in other vascular beds for endovascular treatment of heavily calcified lesions. In the present report, we have demonstrated the application of intravascular lithotripsy for heavily calcified carotid lesions, enabling treatment with TCAR for those who otherwise might be at high risk of transfemoral carotid artery stenting or carotid endarterectomy.

Intracranial vascular feature changes in time of flight MR angiography in patients undergoing carotid revascularization surgery

PURPOSE

To characterize the intracranial vascular features extracted from time of flight (TOF) images and their changes from baseline to follow-up in patients undergoing carotid revascularization, using arterial spin labeling (ASL) cerebral blood flow (CBF) measurement as a reference.

METHODS

In this retrospective study, brain TOF and ASL images of 99 subjects, acquired before, within 48 h, and/or 6 months after, carotid revascularization surgery were analyzed. TOF images were analyzed using a custom software (iCafe) to quantify intracranial vascular features, including total vessel length, total vessel volume, and number of branches. Mean whole-brain CBF was calculated from ASL images. ASL scans showing low ASL signal in the entire flow territory of an internal carotid artery (ICA), which may be caused by labeling failure, were excluded. Changes and correlations between time points were analyzed separately for TOF intracranial vascular features and ASL CBF.

RESULTS

Similar to ASL CBF, TOF vascular features (i.e. total vessel length, total vessel volume and number of branches) increased dramatically from baseline to post-surgery, then returned to a level slightly higher than the baseline in long-term follow-up (All P < 0.05). Correlation between time points was observed for all three TOF vascular features but not for ASL CBF.

CONCLUSION

Intracranial vascular features, including total vessel length, total vessel volume and number of branches, extracted from TOF images are useful in detecting brain blood flow changes induced by carotid revascularization surgery.

MicroRNA-503-5p improves carotid artery stenosis by inhibiting the proliferation of vascular smooth muscle cells

Carotid artery stenosis (CAS) is a common arteriosclerotic vascular disease affected by vascular smooth muscle cells (VSMCs). The aim of the present study was to investigate the expression and diagnostic value of microRNA (miR)-503-5p in asymptomatic patients with CAS and to further explore the effect of miR-503-5p on VSMC proliferation. The levels of miR-503-5p in the serum of 62 asymptomatic patients with CAS and 60 healthy controls were detected by reverse transcription-quantitative PCR. The association between miR-503-5p and the clinical characteristics of the patients was analyzed using the χ² test. A receiver operating characteristic curve was drawn to evaluate the diagnostic value of miR-503-5p to distinguish asymptomatic patients with CAS from healthy controls. Finally, miR-503-5p inhibitors and mimics were transfected into VSMCs in vitro to detect the effect of miR-503-5p on the proliferation ability through Cell Counting Kit-8 assays. The serum levels of miR-503-5p in asymptomatic patients with CAS were significantly reduced as compared with those in healthy individuals. The expression levels of miR-503-5p were significantly associated with diabetes and arterial stenosis. Furthermore, the area under the ROC curve was 0.817, the specificity was 79.03% and the sensitivity was 83.30%, which proved that miR-503-5p had a high diagnostic accuracy in patients with CAS. Finally, the in vitro proliferation assay indicated that overexpression of miR-503-5p significantly inhibited the proliferation of VSMCs. In conclusion, miR-503-5p is a potential diagnostic biomarker for asymptomatic CAS and overexpression of miR-503-5p may inhibit the proliferation of VSMCs and improve CAS.

[Long-term results of surgical and conservative treatment of patients with occlusive-stenotic lesions of carotid arteries]

OBJECTIVE

To compare long-term outcomes in patients after carotid endarterectomy and those who refused surgical correction and received only conservative treatment.

MATERIAL AND METHODS

There were 1035 carotid endarterectomies performed at the Kemerovo Regional Clinical Hospital and Kemerovo Regional Clinical Cardiology Dispensary for the period 2014-2017. Surgery was refused by 136 patients for the same time. Thus, two groups of patients were formed: 1 - carotid endarterectomy group; 2 - conservative treatment group.

INCLUSION CRITERIA

significant carotid stenosis, absence of severe neurological deficit (over 25 scores by the National Institutes of Health Stroke Scale), absence of concomitant diseases limiting long-term follow-up.

RESULTS

Lethal outcome (p=0.0038) and fatal acute cerebrovascular accident (p=0.0005) were significantly more common in the 2^nd group in long-term follow-up period. Thus, combined endpoint took the greatest values in patients who refused surgery compared with patients who received surgical treatment (p=0.0001). It should be noted that ischemic stroke de novo occurred in 9 (6.6%) patients of the 2^nd group after 10.8 ± 2.5 months. This complication required subsequent hospitalization for carotid endarterectomy.

CONCLUSION

Preventive role of carotid endarterectomy was convincingly proved in comparison with drug therapy regarding mortality and fatal ischemic stroke in patients with significant carotid stenoses within 2.5 years of follow-up period.

THE POSSIBILITIES OF USING A NEW FIXED-DOSE COMBINATION OF ROSUVASTATIN AND ACETYLSALICYLIC ACID: FOCUS GROUPS OF PATIENTS

The review focuses on the impairment of the carotid, coronary arteries and lower-extremity arterial disease. Systemic involvement of various vascular beds in atherogenesis is emphasized. Epidemiological characteristics of morbidity and mortality from the main clinical manifestations of atherosclerosis - ischemic stroke, ischemic heart disease and lower-extremity arterial disease are given. The current principles of drug therapy are considered from the point of view of improving the prognosis and eliminating ischemia. The basic positions of International and Russian clinical recommendations on the management of patients with the presence of certain clinical manifestations of atherosclerosis are discussed. Detailed administration schemes and the preferred doses of statins and antiplatelet agents depending on the localization of atherosclerotic lesion and the severity of stenosis are described. The target blood lipids levels in the treatment with statins are given. The advantages of statins as drugs that reduce the risk of cardiovascular complications are presented. Current data on the pattern of antiplatelet use, including acetylsalicylic acid, in individuals with clinical manifestations of atherosclerosis are given. The principal tactic of dual antiplatelet therapy and schemes of its use in patients undergoing percutaneous coronary intervention, coronary artery bypass surgery and in individuals with a history of acute coronary disorders are considered.

[Changes in cerebral perfusion in patients undergoing revascularization of carotid artery stenosis]

Ischemic stroke is caused by atherosclerotic lesions in extra- and intracranial arteries in about 25% of cases. Revascularization surgery has been long and widely used for secondary prevention of ischemic stroke in patients with atherosclerotic lesions of the carotid arteries. However, currently the changes in cerebral perfusion in patients with atherosclerotic lesions of brachiocephalic arteries, who underwent surgical revascularization, are still not fully understood. This article highlights the issues of changes of cerebral hemodynamics in patients undergoing surgery on the carotid arteries.

Clinical Comparison of Outcomes of Early versus Delayed Carotid Artery Stenting for Symptomatic Cerebral Watershed Infarction due to Stenosis of the Proximal Internal Carotid Artery

The aim of this study was to compare the clinical outcomes of early versus delayed carotid artery stenting (CAS) for symptomatic cerebral watershed infarction (sCWI) patients due to stenosis of the proximal internal carotid artery. We retrospectively collected clinical data of those who underwent early or delayed CAS from March 2011 to April 2014. The time of early CAS and delayed CAS was within a week of symptom onset and after four weeks from symptom onset. Clinical data such as second stroke, the National Institutes of Health Stroke Scale (NHISS) score, and modified Rankin Scale (mRS) score and periprocedural complications were collected. The rate of second stroke in early CAS group is lower when compared to that of delayed CAS group. There was no significant difference regarding periprocedural complications in both groups. There was a significant difference regarding mean NHISS score 90 days after CAS in two groups. Early CAS group had a significant better good outcome (mRS score ≤ 2) than delayed CAS group. We suggest early CAS for sCWI due to severe proximal internal carotid artery stenosis as it provides lower rate of second stroke, comparable periprocedural complications, and better functional outcomes compared to that of delayed CAS.

Smooth muscle immaturity in the carotid arterial neointima as a prognostic marker for systemic atherogenic cardiovascular events in the Asian male

Although immaturity of neointimal smooth muscle cells (SMCs) in coronary arteries has recently been demonstrated to be associated with acute coronary syndrome, the carotid arterial counterpart has not been investigated. We hypothesized that the same investigation of carotid endarterectomy specimens might contribute to living patients. Carotid endarterectomy specimens from 33 Asian males who underwent a 5-year follow-up were examined. Age, atherosclerotic risk factors, and percentage stenosis were investigated. Histologically, the fibrous cap/lipid core ratio was measured. Maturation of SMCs was assessed by the h-caldesmon/smooth muscle actin (SMA) ratio by immunohistochemistry in 3 different regions (luminal, medial, and opposite side of lipid core) in the neointima. Associations of these factors with preoperative symptoms along with postoperative systemic atherogenic cardiovascular events were analyzed. It was revealed that fibrous cap/lipid core ratio was significantly lower in symptomatic than in asymptomatic patients, while the h-caldesmon/SMA ratio was significantly lower in patients with than without postoperative systemic atherogenic cardiovascular events by the Student's t-test (P<0.05). Logistic regression model demonstrated that younger age and a lower h-caldesmon/SMA ratio were associated with postoperative systemic atherogenic cardiovascular events (P<0.05). This result was not different when 3 different regions were each analyzed instead. Immaturity of neointimal SMCs shown by a lower h-caldesmon/SMA ratio by immunohistochemistry was associated with systemic atherogenic cardiovascular events. Thus, this finding may be predictive of these events after carotid endarterectomy. Uniform results among different neointimal regions suggest that immaturity of neointimal SMCs causes plaque instability and does not occur secondarily to plaque instability.

Carotid Artery Stenosis with Acute Ischemic Stroke: Stenting versus Angioplasty

BACKGROUND

When a patient with carotid artery stenosis presents emergently with acute ischemic stroke, the optimum treatment plan is not clearly defined. If intervention is warranted, and open surgery is prohibitive, endovascular revascularization may be performed. The use of stents places the patient at additional risk due to their thrombogenic potential. The intent of this study was to compare outcomes following endovascular approaches (angioplasty alone vs. stent) in the setting of acute stroke.

METHODS

We extracted a population from the National Inpatient Sample (2012) and the Nationwide Inpatient Sample (2003-2011) composed of patients with carotid artery stenosis with infarction that were admitted nonelectively and received endovascular revascularization. Patients treated with mechanical thrombectomy or thrombolysis were excluded. Categorical variables were compared between treatment groups with Chi-squared tests. Binary logistic regression was performed to evaluate mortality and iatrogenic stroke while controlling for age, case severity, and comorbidity burden.

RESULTS

About 6,333 admissions met our criteria. A majority were treated via stenting (89%, n = 5,608). The angioplasty-alone group had significantly higher mortality (9.0% vs. 3.8%, p < 0.001) and iatrogenic stroke rate (3.9% vs. 1.9%, p < 0.001) than the stent group. The adjusted odds ratios of mortality and iatrogenic stroke for patients treated with angioplasty alone were 1.953 (p < 0.001) and 1.451 (p = 0.105), respectively, in comparison to patients treated with carotid stenting.

CONCLUSION

Multivariate analysis found the risk of mortality to be elevated following angioplasty alone. This may represent selection bias, but it also may indicate that symptomatic patients with stroke suffer from severe stenosis and unstable plaques that would benefit from stent placement. These results would caution angioplasty alone as an arm of a future randomized trial involving this severely burdened patient population requiring urgent intervention.

Comparative Review of the Treatment Methodologies of Carotid Stenosis

The treatment of carotid stenosis entails three methodologies, namely, medical management, carotid angioplasty and stenting (CAS), as well as carotid endarterectomy (CEA). The North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST) have shown that symptomatic carotid stenosis greater than 70% is best treated with CEA. In asymptomatic patients with carotid stenosis greater than 60%, CEA was more beneficial than treatment with aspirin alone according to the Asymptomatic Carotid Atherosclerosis (ACAS) and Asymptomatic Carotid Stenosis Trial (ACST) trials. When CAS is compared with CEA, the CREST resulted in similar rates of ipsilateral stroke and death rates regardless of symptoms. However, CAS not only increased adverse effects in women, it also amplified stroke rates and death in elderly patients compared with CEA. CAS can maximize its utility in treating focal restenosis after CEA and patients with overwhelming cardiac risk or prior neck irradiation. When performing CEA, using a patch was equated to a more durable result than primary closure, whereas eversion technique is a new methodology deserving a spotlight. Comparing the three major treatment strategies of carotid stenosis has intrinsic drawbacks, as most trials are outdated and they vary in their premises, definitions, and study designs. With the newly codified best medical management including antiplatelet therapies with aspirin and clopidogrel, statin, antihypertensive agents, strict diabetes control, smoking cessation, and life style change, the current trials may demonstrate that asymptomatic carotid stenosis is best treated with best medical therapy. The ongoing trials will illuminate and reshape the treatment paradigm for symptomatic and asymptomatic carotid stenosis.

Effect of Carotid Artery Stenting on Cognitive Function in Patients with Internal Carotid Artery Stenosis and Cerebral Lacunar Infarction: A 3-Year Follow-Up Study in China

BACKGROUND AND OBJECTIVES

Carotid artery stenting (CAS) is an important therapeutic strategy for patients with carotid artery stenosis. However, the potential influence of CAS on cognitive function in patients with carotid artery stenosis and cerebral lacunar infarction has not been determined. This study investigated changes in cognitive function associated with CAS and the factors related to these changes.

METHODS

This prospective cohort study comprised 579 Chinese patients with cerebral lacunar infarction and carotid artery stenosis for whom CAS was indicated, and a matched control group of 552 healthy individuals. Cognitive function before CAS and at scheduled intervals from 6 months to 3 years was assessed with instruments that included the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) scale. Potential factors that might affect cognitive function were analyzed via logistic regression.

RESULTS

The MMSE and MoCA scores of the patients before CAS were significantly lower than that of the control subjects. These scores were significantly higher 6 months after CAS and sustained or increased throughout the 3-year follow-up. Also significantly improved after CAS from baseline were scores for an alternating trail test, cube copying, clock-drawing, attention, and delayed recall in an auditory-verbal learning test. Logistic regression analyses showed that age greater than 65 y, little education, diabetes, and hypertension were independent risk factors for deteriorated MoCA scores 3 years after CAS.

CONCLUSION

CAS was associated with significantly improved cognitive function in cerebral lacunar infarction patients with severe stenosis.