Occam's razor: Intervene early to prevent more strokes!

Robustness and classification capabilities of MRI radiomic features in identifying carotid plaque vulnerability

OBJECTIVES

To assess how radiomic features may be combined with plaque morphological and compositional features identified by multi-contrast MRI to improve upon conventional risk assessment models in determining culprit carotid artery lesions.

METHODS

Fifty-five patients (mean age: 62.6; 35 males) with bilateral carotid stenosis who experienced transient ischaemic attack (TIA) or stroke were included from the CARE-II multi-centre carotid imaging trial (ClinicalTrials.gov Identifier: NCT02017756). They underwent MRI within 2 weeks of the event. Classification capability in distinguishing culprit lesions was assessed by machine learning. Repeatability and reproducibility of the results were investigated by assessing the robustness of the radiomic features.

RESULTS

Radiomics combined with a relatively conventional plaque morphological and compositional metric-based model provided incremental value over a conventional model alone (area under curve [AUC], 0.819 ± 0.002 vs 0.689 ± 0.019, respectively, P = .014). The radiomic model alone also provided value over the conventional model (AUC, 0.805 ± 0.003 vs 0.689 ± 0.019, respectively, P = .031). T2-weighted imaging-based radiomic features had consistently higher robustness and classification capabilities compared with T1-weighted images. Higher-dimensional radiomic features outperformed first-order features. Grey Level Co-occurrence Matrix, Grey Level Dependence Matrix, and Grey Level Size Zone Matrix sub-types were particularly useful in identifying textures which could detect vulnerable lesions.

CONCLUSIONS

The combination of MRI-based radiomic features and lesion morphological and compositional parameters provided added value to the reference-standard risk assessment for carotid atherosclerosis. This may improve future risk stratification for individuals at risk of major adverse ischaemic cerebrovascular events.

ADVANCES IN KNOWLEDGE

The clinical relevance of this work is that it addresses the need for a more comprehensive method of risk assessment for patients at risk of ischaemic stroke, beyond conventional stenosis measurement. This paper shows that in the case of carotid stroke, high-dimensional radiomics features can improve classification capabilities compared with stenosis measurement alone.

Vascular Quality Initiative assessment of compliance with Society for Vascular Surgery clinical practice guidelines on the management of extracranial cerebrovascular disease

OBJECTIVES

Compliance with Society for Vascular Surgery (SVS) clinical practice guidelines (CPGs) is associated with improved outcomes for the treatment of abdominal aortic aneurysm, but this has not been assessed for carotid artery disease. The Vascular Quality Initiative (VQI) registry was used to examine compliance with the SVS CPGs for the management of extracranial cerebrovascular disease and its impact on outcomes.

METHODS

The 2021 SVS extracranial cerebrovascular disease CPGs were reviewed for evaluation by VQI data. Compliance rates by the center and provider were calculated, and the impact of compliance on outcomes was assessed using logistic regression with inverse probability-weighted risk adjustment for each CPG recommendation, allowing for clustering by the center. Our primary outcome was a composite end point of in-hospital stroke/death. As a secondary analysis, compliance with the 2021 SVS carotid implementation document recommendations and associated outcomes were also assessed.

RESULTS

Of the 11 carotid CPG recommendations, 4 (36%) could be evaluated using VQI registry data. Median center-specific CPG compliance ranged from 38% to 95%, and median provider-specific compliance ranged from 36% to 100%. After adjustment, compliance with 2 of the recommendations was associated with lower rates of in-hospital stroke/death: first, the use of best medical therapy (antiplatelet and statin therapy) in low/standard surgical risk patients undergoing carotid endarterectomy for >70% asymptomatic stenosis (event rate in compliant vs noncompliant cases 0.59% vs 1.3%; adjusted odds ratio: 0.44, 95% confidence interval: 0.29-0.66); and second, carotid endarterectomy over transfemoral carotid artery stenting in low/standard surgical risk patients with >50% symptomatic stenosis (1.9% vs 3.4%; adjusted odds ratio: 0.55, 95% confidence interval: 0.43-0.71). Of the 132 implementation document recommendations, only 10 (7.6%) could be assessed using VQI data, with median center- and provider-specific compliance rates ranging from 67% to 100%. The impact of compliance on outcomes could only be assessed for 6 (4.5%) of these recommendations, and compliance with all 6 recommendations was associated with lower stroke/death.

CONCLUSIONS

Few SVS recommendations could be assessed in the VQI because of incongruity between the recommendations and the VQI data variables collected. Although guideline compliance was extremely variable among VQI centers and providers, compliance with most of these recommendations was associated with improved outcomes after carotid revascularization. This finding confirms the value of guideline compliance, which should be encouraged for centers and providers. Optimization of VQI data to promote evaluation of guideline compliance and distribution of these findings to VQI centers and providers will help facilitate quality improvement efforts in the care of vascular patients.

"Timing to carotid endarterectomy affects early and long term outcomes of symptomatic carotid stenosis."

OBJECTIVE

The aim of this study is to evaluate early and long-term outcomes according to the timing to carotid endarterectomy (CEA) of symptomatic carotid stenosis.

METHODS

Consecutive CEAs with selective shunting for symptomatic carotid stenosis ≥50% performed between 2009 and 2020. Patients had acute neurological impairment on presentation, defined as <5 points on the National Institutes of Health Stroke Scale(NIHSS). We grouped patients according to time between index event and CEA: the first group was operated between 0-2 days, the second group between 3 and 7 days, the third group between 8 and 14 days and the last group after 15 days. Thirty-day neurological status improvement was defined as a decrease (≥1) in the 30-day NIHSS score vs. NIHSS score immediately before surgery.

RESULTS

500 CEAs were performed. The perioperative combined stroke and mortality rate was 3.6% (18/500), representing a perioperative mortality rate of .2 (n=1) and stroke rate of 3.4% (n=17). Overall freedom from stroke was 95% at 1 year, 89 % at 6 years, and 88% at 10 years. Annual stroke rate was 0.6% after the 30-day period. Thirty-day improvement in neurologic status occurred in 103 patients (20.6%), while in 380 (76%) neurologic status was unchanged, and 17 (3.4%) experienced worsening of their neurologic status. Patients treated within 7 days from the index event had significant benefit (OR=2.6) in the 30-day neurological improvement vs. those treated after 7 days from the index event. Timing to CEA <2 days increased significantly the risk of late stroke (OR=9.7).

CONCLUSIONS

The ideal timing for performing CEA is between 3 and 7 days from the index event if NIHSS <5 as it is associated with the best rates of improvement in neurological status and durability in the long term. Very early CEA (<48 hours) was associated with increased late stroke occurrence.

[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.

Concomitant Surgical Treatment of Symptomatic Carotid Artery Disease With a Coexisting Shamblin I Carotid Body Tumor

Symptomatic carotid artery atherosclerotic disease is an indication for carotid artery endarterectomy. The coexistence of carotid body tumors (CBTs) with symptomatic carotid disease is rarely encountered and adds significant challenges to vascular surgeons, with a reported overall mortality for patients who undergo endarterectomy and tumor excision of 8.8%, as opposed to the 2% for those who had CBT excision only. We describe the case of a 79-year-old female who experienced an acute cerebrovascular accident in the left hemisphere; duplex ultrasound revealed high-grade carotid stenosis in the left side and the presence of a Shamblin I CBT. The risks and benefits of the planned operation were reviewed, and the decision was made to proceed with early carotid endarterectomy and concomitant surgical resection of the tumor using the retrocarotid dissection technique. The patient recovered well, and at 11 months from the combined procedure, her neurological deficits improved significantly.

A short time interval between the neurologic index event and carotid endarterectomy is not a risk factor for carotid surgery

OBJECTIVE

Current guidelines recommend that carotid endarterectomy (CEA) be performed as early as possible after the neurologic index event in patients with 50% to 99% carotid artery stenosis. However, recent registry data showed that patients treated ≤48 hours had a significantly increased perioperative risk. Therefore, the aim of this single-center study was to determine the effect of the time interval between the neurologic index event and CEA on the periprocedural complication rate at our institution.

METHODS

Prospectively collected data for 401 CEAs performed between 2004 and 2014 for symptomatic carotid stenosis were analyzed. Patients were divided into four groups according to the interval between the last neurologic event and surgery: group I, 0 to 2 days; group II, 3 to 7 days; group III, 8 to 14 days; and group IV, 15 to 180 days. The primary end point was the combined rate of in-hospital stroke or mortality. Data were analyzed by way of χ² tests and multivariable regression analysis.

RESULTS

The patients (68% men) had a median age of 70 years (interquartile range, 63-76 years). The index events included transient ischemic attack in 43.4%, amaurosis fugax in 25.4%, and an ipsilateral stroke in 31.2%. CEA was performed using the eversion technique in 61.1% of patients, and 50.1% were treated under locoregional anesthesia. The perioperative combined stroke and mortality rate was 2.5% (10 of 401), representing a perioperative mortality rate of 1.0% and stroke rate of 1.5%. Overall, myocardial infarction, cranial nerve injuries, and postoperative bleeding occurred in 0.7%, 2.2%, and 1.7%, respectively. We detected no significant differences for the combined stroke and mortality rate by time interval: 3% in group I, 3% in group II, 2% in group III, and 2% in group IV. Multivariable regression analysis showed no significant effect of the time interval on the primary end point.

CONCLUSIONS

The combined mortality and stroke rate was 2.5% and did not differ significantly between the four different time interval groups. CEA was safe in our cohort, even when performed as soon as possible after the index event.

Urgent carotid intervention is safe after thrombolysis for minor to moderate acute ischemic stroke

OBJECTIVE

Carotid intervention shortly after an acute neurologic ischemic event is being performed more frequently in stroke centers to reduce the risk of recurrent stroke. Thrombolysis with recombinant tissue plasminogen activator (tPA) is offered to select patients with ischemic stroke symptoms who present within 4.5 hours. However, there is a paucity of data as to whether tPA followed by urgent carotid endarterectomy (CEA) or carotid artery stenting (CAS) has an increased risk of complications, particularly intracerebral hemorrhage (ICH). We sought to determine the periprocedural complications of urgently performed CEA or CAS following tPA.

METHODS

From January 2009 to January 2015, 762 patients underwent carotid interventions (CEA, n = 440; CAS, n = 322) at a tertiary referral center and 165 patients (21.6%) underwent an urgent CEA or CAS during the index hospitalization for an acute transient ischemic attack or stroke. We compared the effect of intravenous tPA on 30-day complications, including ICH. The χ(2) and Fisher exact tests were used to determine significance between groups.

RESULTS

During the 6-year period, 165 patients underwent urgent carotid interventions (CEA, n = 135; CAS, n = 30) for acute neurologic symptoms. Of these, 19% (31 patients [CEA, n = 25; CAS, n = 6]) had tPA for an acute stroke; the remaining (134 patients [CEA, n = 110; CAS, n = 24]) fell outside of the tPA time window. Most strokes were minor or moderate with a mean National Institutes of Health Stroke Scale (NIHSS) score of 6.6 (range, 0-19). The mean time to intervention for both groups was 2.4 days (0-15 days). The 30-day stroke, death, and myocardial infarction rates were 9.7% (3 of 31) for the tPA group compared with 4.5% (6 of 134) for the no-tPA group (P = .37). Including bleeding complications in these 30-day outcomes, there was no difference between the tPA (3 of 31) and the no-tPA cohorts (8 of 134; P = .43). In the tPA group, there were one ICH, one neck hematoma/death, and an additional death; in the no-tPA group, there were one ICH, two neck hematomas, one stroke, two myocardial infarctions, one ICH/death, and one additional death. No significant increased rates of bleeding were noted within the tPA group (2 of 31) compared with the no-tPA group (4 of 134; P = .32). Moreover, in the tPA cohort, more than half of the patients (17 of 31) underwent revascularization within 72 hours (CEA = 13; CAS = 4) with outcomes similar to those who underwent revascularization after 72 hours.

CONCLUSIONS

Thrombolysis followed by urgent CEA or CAS is not associated with an increased risk of complications in select patients who present with acute neurologic symptoms. Selection of patients is important; there was no ICH and only one death in each group for patients with minor to moderate ischemic stroke (NIHSS score <10).

Debate: Whether carotid endarterectomy is safer than stenting in the hyperacute period after onset of symptoms

The carotid artery has been a regular battleground for debates regarding many issues, including appropriate management of symptomatic and asymptomatic lesions, the conduct, timing, and safety of such interventions, and now, whether endarterectomy or stenting is safer in the hyperacute period. Our discussants agree that, as a prophylactic procedure, a carotid intervention should occur early after index symptoms to prevent as many strokes as possible. However, which intervention is best?

Cost-Effectiveness of Carotid Endarterectomy versus Carotid Artery Stenting for Treatment of Carotid Artery Stenosis

BACKGROUND

Symptomatic or asymptomatic patients with significant carotid artery stenosis (range, 70% to 99%) generally undergo either carotid artery endarterectomy (CEA) or carotid artery stenting (CAS) to prevent stroke. In this study, we evaluated the cost effectiveness of these two treatment modalities.

METHODS

A total of 47 patients (mean age, 67.1±9.1 years; male, 87.2%) undergoing either CEA (n=28) or CAS (n=19) for the treatment of significant carotid artery stenosis were enrolled in this study. Hospitalization costs were subdivided into three parts, namely pre-procedure, procedure and resource, and post-procedure costs.

RESULTS

Total hospitalization costs were similar in both groups of CEA and CAS (6,377 thousand won [TW] vs. 6,703 TW, p=0.255); however, the total cost minus the pre-procedure cost was higher in the CAS group than in the CEA group (4,948 TW vs. 5,941 TW, p<0.0001). The pre-procedure cost of the CEA group was higher than that of the CAS group (1,429 TW vs. 762 TW, p<0.0001). However, the procedure and resource cost was higher in the CAS group because the resource cost was approximately three times higher in the CAS group than in the CEA group. The post-procedure cost was higher in the CEA group because hospital stays were approximately two times longer.

CONCLUSION

The total hospitalization cost was not different between the CEA and the CAS groups. The pre-procedure cost was high in the CEA group, but the cost from procedure onset to discharge, including the resource cost, was significantly lower in this group.

Impact of plaque haemorrhage and its age on structural stresses in atherosclerotic plaques of patients with carotid artery disease: an MR imaging-based finite element simulation study

Plaque haemorrhage (PH) in atherosclerotic plaques is associated with recurrent thromboembolic ischaemic events. The healing process predominantly involves the repair of the plaque rupture site and the replacement of fresh PH with chronic PH, which is either reabsorbed or replaced by fibrous tissue. The extent to which the presence of PH, and its type i.e. fresh or chronic, affects plaque stability remains unexplored. Finite element analysis (FEA)-based biomechanical stress simulations can provide quantification of the percentage contribution of PH and its types to the biomechanical stresses of plaques, thereby providing information about its role in plaque stability. Fifty-two patients with atherosclerotic carotid disease underwent high resolution magnetic resonance (MR) imaging of their carotid arteries in a 1.5 Tesla MR system. Twenty-three patients had MR-identifiable PH and were selected. Only those images of these patients were used for simulations, which had evidence of PH. Manual segmentation of plaque components, such as lipid pool, fibrous tissue, calcium and PH, was done using carotid MR images. Plaque components and vessel wall were modelled as isotropic, incompressible hyperelastic materials with non-linear properties undergoing deformation under patient-specific blood pressure loading. Two dimensional structure-only FEA was used for quantification of maximum critical stress (M-CStress) of plaques. The median M-CStress of symptomatic patients with fresh PH was 159 kPa (IQR: 114-253). Because PH usually occurs within the lipid pool, when the simulation was repeated with lipid pool replacing fresh PH to simulate the pre-rupture plaque state, M-CStress was reduced by 26% [118 kPa (IQR: 79-189) (P=0.001)]. When fresh PH was replaced with chronic PH it resulted in a 30% reduction in the M-CStress [118 kP (IQR: 79-189), (P=0.001)]. PH affects stresses within atheroma to various degrees depending on its type, thereby influencing plaque stability to a different extent, with fresh PH significantly increasing the biomechanical stresses. Plaque component-dependent stress analysis has the potential of identifying the critical nature of various plaque components.