Characterization and Natural History of Patients with Internal Carotid Occlusion: A Comparative Study

Association between Hospital Carotid Endarterectomy Procedure Volumes and In-Hospital Mortality in São Paulo State

Background

Previous studies indicate an inverse relationship between hospital volume and mortality after carotid endarterectomy. However, data at the level of Brazil are lacking.

Objectives

To assess the relationship between hospital carotid endarterectomy procedure volumes and mortality in the state of São Paulo.

Methods

Data from the São Paulo State Hospital Information System on all carotid endarterectomies performed between 2015 and 2019 were analyzed. Hospitals were categorized into clusters by annual volume of surgeries (1-10, 11-25, and ≥26). Multiple logistic regression models were used to determine whether the volume of carotid endarterectomy procedures was an independent predictor of in-hospital mortality among patients undergoing this procedure.

Results

Crude in-hospital mortality was nearly 60 percent lower in patients who underwent carotid endarterectomy at the highest volume hospitals than among those who underwent endarterectomy at the lowest volume hospitals (unadjusted OR of survival to hospital discharge, 2.41; 95% CI, 1.11-5.23; p = 0.027). Although this lower rate represents 1.5 fewer deaths per 100 patients treated, high-volume centers are more likely than low-volume centers to perform elective procedures, thus the analysis did not retain statistical significance when adjusted for admission character (OR, 1.69; 95% CI, 0.74-3.87; p = 0.215).

Conclusions

In a contemporary Brazilian registry, higher volume carotid endarterectomy centers were associated with lower in-hospital mortality than lower volume centers. Further studies are needed to verify this relationship considering the presence of symptoms in patients.

The Natural History of Carotid Artery Occlusions Diagnosed on Duplex Ultrasound

BACKGROUND

There is a paucity of literature on the natural history of extracranial carotid artery occlusion (CAO). This study reviews the natural history of this patient cohort.

METHODS

This single-institution retrospective analysis studied patients with CAO diagnosed by duplex ultrasound between 2010 and 2021. Patients were identified by searching our office-based Intersocietal Accreditation Commission accredited vascular laboratory database. Imaging and clinical data were obtained via our institutional electronic medical record. Outcomes of interest included ipsilateral stroke, attributable neurologic symptoms, and ipsilateral intervention after diagnosis.

RESULTS

The full duplex database consisted of 5,523 patients who underwent carotid artery duplex examination during the study period. The CAO cohort consisted of 139 patients; incidence of CAO was 2.5%. Mean age at diagnosis was 69.7 years; 31.4% were female. Hypertension (72.7%), hyperlipidemia (64.7%), and prior smoking (43.9%) were the most common comorbid conditions. Of the CAO cohort, 61.3% (n = 85) of patients were asymptomatic at diagnosis; 38.8% (n = 54) were diagnosed after a stroke or transient ischemic attack occurring within 6 months prior to diagnosis, with 21.6% occurring ipsilateral to the CAO and 10.1% occurring contralateral to the CAO. 7.2% (n = 10) had unclear symptoms or laterality at presentation. Of the CAO cohort, 95 patients (68.3%) had duplex imaging follow-up (mean 42.7 ± 31.3 months). Of those with follow-up studies, 7 patients (5.0%) developed subsequent stroke ipsilateral to the CAO with mean occurrence 27.8 ± 39.0 months postdiagnosis. In addition, 5 patients (3.6%) developed other related symptoms, including global hypoperfusion (2.4%) and transient ischemic attack (1.2%). Of those, 95 patients with follow-up duplex ultrasound imaging, 6 (4.3%) underwent eventual ipsilateral intervention, including carotid endarterectomy (n = 4), transfemoral carotid artery stent (n = 1), and carotid bypass (n = 1), with mean occurrence 17.7 ± 23.7 months postdiagnosis. The aggregate rate of ipsilateral cerebrovascular accident, attributable neurologic symptoms, or ipsilateral intervention was 11.5%. Of 95 patients with follow-up duplex ultrasound imaging, 5 underwent subsequent duplex studies demonstrating ipsilateral patency, resulting in a 5.3% discrepancy rate between sequential duplex studies. All 6 patients undergoing intervention received periprocedural cross-sectional imaging (magnetic resonance angiography or computed tomography angiography). In 5 of these 6 patients, cross-sectional demonstrated severe stenosis rather than CAO, disputing prior duplex ultrasound findings.

CONCLUSIONS

In this large, institutional cohort of patients with a CAO diagnosis on duplex ultrasound, a clinically meaningful subset of patients experienced cerebrovascular accident, related symptoms, or intervention. We also found a notable rate of temporal duplex discrepancies among patients with CAO diagnoses and discrepancies between CAO diagnosis per duplex ultrasound and findings on cross-sectional imaging for those patients who underwent intervention. These results suggest that use of a single duplex ultrasound as a sole diagnostic tool in CAO may not be sufficient and that physicians should consider close duplex ultrasound surveillance of these patients, potentially in conjunction with additional confirmatory imaging modalities. Further investigation into optimal workup and surveillance protocols for CAO is needed.

Non-association of stroke risk with intracranial hemodynamic steal in patients with symptomatic internal carotid artery occlusions

OBJECTIVES

Paradoxical intracranial hemodynamic steal (IHS) is known in patients having persistent proximal arterial occlusions and is linked with early neurological worsening. However, stroke risk specific to symptomatic internal carotid artery occlusions (SICAO) having paradoxical IHS is unknown. Therefore, we aimed to investigate the association of paradoxical IHS in SICAO patients with stroke recurrence during a one-year follow-up.

MATERIALS AND METHODS

We prospectively enrolled adult patients having SICAO with a recent history of ischemic events. Steal magnitude (SM) to classify patients in IHS and non-IHS categories was evaluated by a breath-holding test using bilateral transcranial doppler (TCD). Patients were prescribed optimal medical therapy and followed up for one year for any ischemic stroke/TIA/cardiovascular death.

RESULTS

36 SICAO patients, mean age of 56 years, were assessed using TCD at median 22.5 days (Interquartile range, IQR= 9-42), and 11 (30.6%) had paradoxical IHS with median SM 12% (IQR= 6%-18%). On follow-up, 7 (19.4%) patients had event recurrence and its association with IHS was non-significant (IHS vs non-IHS, 18.2% vs 20%; Log-rank statistics=0.006; P=0.940). On Cox regression analysis, event recurrence was independently associated with the presence of significant contralateral stenosis only (regression coefficient= 2.237; P= 0.012; 95% CI= 1.63-53.89).

CONCLUSIONS

IHS prevalence among SICAO is high. However, paradoxical IHS was not associated with an increased risk of stroke in SICAO. Therefore, the presence of paradoxical IHS in SICAO may be considered a transit state and does not necessarily imply an increased risk of stroke.

Surgery of acute occlusion of the extracranial internal carotid artery - a meta-analysis

Acute occlusion of the extracranial internal carotid artery (eICA) is associated with poor prognosis. Surgical desobliteration has not received adequate attention in recent years. We therefore conducted a literature review and meta-analysis of surgical studies published after 2000 that treated eICA occlusion surgically in an emergency setting. The search identified 10 relevant articles that included a total of 175 patients. The outcomes analysed included rates of recanalization (93 %), early neurological improvement (66 %), modified Rankin Scale 0-2 (62 %), mortality (5 %), early reocclusion (4 %), in-hospital stroke (4 %) and symptomatic intracerebral haemorrhage (4 %). In conclusion, acute surgical desobliteration of eICA occlusion leads to high rates of recanalization and a majority of patients experience early neurological improvement and achieve favourable outcome. Rates of mortality, early reocclusion, in-hospital stroke and sICH are acceptable in the view of unfavourable natural history.