An update on the role of proximal occlusion devices in carotid artery stenting

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).

The safety and efficacy of the Mo.Ma system device for carotid artery stenting: A single-center experience from Taiwan

Background

Proximal protection devices, such as the Mo.Ma system provides better neurological outcomes than the distal filter system in the carotid artery stenting (CAS) procedure. This study first evaluated the safety and efficacy of the Mo.Ma system during CAS in a single tertiary referral hospital from Taiwan. The outcomes of distal vs. proximal embolic protection devices were also studied.

Methods

A total of 294 patients with carotid artery stenosis who underwent the CAS procedure were retrospectively included and divided into two groups: 152 patients in the distal filter system group and 142 patients in the Mo.Ma system. The outcomes of interest were compared between the two groups. The factors contributing to occlusion intolerance (OI) in the Mo.Ma system were evaluated.

Results

The procedure success rates were more than 98% in both groups. No major stroke occurred in this study. The minor stroke rates were 2.8% (4/142) and 4.6% (7/152) in the Mo.Ma system and filter system, respectively (p = 0.419). Patients with hypoalbuminemia significantly predicted the risk of stroke with an odds ratio of 0.08 [95% confidence interval (CI), 0.01–0.68, p = 0.020] per 1 g/day of serum albumin in the filter group. A total of 12 patients developed OI in the Mo.Ma system (12/142, 8%). Low occlusion pressure predicted the occurrence of OI in the Mo.Ma group with the hazard ratios of 0.88 (95% CI: 0.82–0.96) and 0.90 (95% CI: 0.84–0.98) per 1 mmHg of occlusion systolic pressure (OSP) and diastolic pressure (ODP), respectively. We further indicated that patients with an OSP of ≥60 mmHg or an ODP of ≥44 mmHg could tolerate the procedure of occlusion time up to 400 s, while patients with an OSP of <49 mmHg or an ODP of <34 mmHg should undergo the procedure of occlusion time less than 300 s to prevent the occurrence of OI.

Conclusion

We have demonstrated the safety and effectiveness of the Mo.Ma system during CAS in an Asia population. By reducing the occlusion time, our study indicated a lower risk of OI in the Mo.Ma system and proposed the optimal occlusion time according to occlusion pressure to prevent OI during the CAS procedure. Further large-scale and prospective studies are needed to verify our results.

Assessing the Suitability of the Carotid Bifurcation for Stenting: Anatomic and Morphologic Considerations

OBJECTIVE

Over the years where stents have been used to treat carotid lesions, a great deal has been learned about which anatomical characteristics lead to adverse outcomes. This review summarizes the anatomic and morphologic characteristics of the carotid vasculature that can help guide patient selection and clinical decision-making.

METHODS

Each of the carotid artery anatomy and lesion characteristics that are relevant to carotid stenting are described in detail. These are accompanied with evidence-based outcomes and results.

RESULTS

Data on the prevalence of carotid artery lesions that are unsuitable for stenting are summarized and the implications of these data for practice are discussed, especially as they pertain to transcarotid artery revascularization.

CONCLUSIONS

CAS can be viable option for carotid revascularization, but the lesion must be acceptable and safe for stent placement. There should be thorough assessment to rule out the presence of severe tortuosity, long-segment disease, severe calcification (circumferential or exophytic), mobile-plaque, swollen ICA sign, and carotid diameters outside the acceptable range. In carefully chosen lesions with the absence of the unfavorable characteristics described-TCAR may offer improved periprocedural success, and CAS may attain better long-term durability.

Risk factors and impact of postoperative hypotension after carotid artery stenting in the Vascular Quality Initiative

OBJECTIVE

Hypotension is a frequent complication of carotid artery stenting (CAS). Although common, its occurrence is unpredictable, and association with adverse events has not been well defined. The aim of this study was to identify predictors of postoperative hypotension after CAS and the association with stroke/transient ischemic attack (TIA), major adverse cardiac events (MACEs), increased length of stay (LOS), and in-hospital mortality.

METHODS

This is a retrospective analysis of all CAS procedures, including transfemoral CAS (TF-CAS) and transcarotid artery revascularization (TCAR), performed in the Vascular Quality Initiative between 2003 and 2018. The primary study end point was postoperative hypotension, defined as hypotension treated with continuous infusion of a vasoactive agent for ≥15 minutes. Secondary end points included any postoperative neurologic events (stroke/TIA), MACEs (myocardial infarction, congestive heart failure, and dysrhythmias), prolonged LOS (>1 day), and in-hospital mortality. Patients' demographics predictive of hypotension were determined by multivariable logistic regression, and a risk score was developed for correlation with outcomes.

RESULTS

During the time period of study, 24,699 patients underwent CAS; 19,716 (80%) were TF-CAS, 3879 (16%) were TCAR, and 1104 (4%) were not defined. Fifty-six percent were for symptomatic disease, 75% were for a primary atherosclerotic lesion, and 72% were performed under local or regional anesthesia. Postoperative hypotension occurred in 15% of TF-CAS and 14% of TCAR patients (P = .50). Patients with hypotension (vs no hypotension) had higher rates of stroke/TIA (7.3% vs 2.6%; P < .001), MACEs (9.6% vs 2.1%; P < .001), prolonged LOS (65% vs 28%; P < .001), and in-hospital mortality (2.9% vs 0.7%; P < .001). By multivariable analysis, risk factors associated with hypotension included an atherosclerotic (vs restenotic) lesion (odds ratio, 2.2; 95% confidence interval, 2.0-2.4; P < .001), female sex (1.3 [1.2-1.4]; P < .001), positive stress test result (1.3 [1.2-1.4]; P < .001), age 70 to 79 years (1.1 [1.1-1.3]; P < .002), age >80 years (1.2 [1.1-1.4]; P < .001), history of myocardial infarction or angina (1.3 [1.2-1.4]; P < .001), and an urgent (vs elective) procedure (1.1 [1.0-1.2]; P < .01). A history of hypertension was protective (0.9 [0.8-0.9]; P < .02). A normalized risk score for hypotension was created from the multivariable model. Increasing risk scores correlated directly with rates of adverse events, including postoperative stroke/TIA, MACEs, increased LOS, and increased in-hospital mortality.

CONCLUSIONS

Hypotension after CAS is associated with adverse neurologic and cardiac events as well as with prolonged LOS and in-hospital mortality. A scoring tool may be valuable in stratifying patients at risk. Interventions aimed at preventing postoperative hypotension may improve outcomes with CAS.

Carotid Artery Stenting in Asymptomatic Carotid Artery Stenosis: JACC Review Topic of the Week

The advance of therapies to reduce the stroke impact of asymptomatic carotid artery stenosis has proved difficult over the last decade. Disagreement concerning the underlying randomized control trials has limited entry into the care arena of endovascular therapies. Recently, advances in percutaneous therapies for carotid artery disease have been reported and provide a substantial database supporting the further incorporation of endovascular-based therapies in patients who need revascularization and meet selection criteria. With a second randomized control trial now published, it is time for a re-evaluation of endovascular therapy as a component of carotid artery care. This review describes the advances in the field in the last 5 years, clarifying the current position of these therapies in the care of the patient with asymptomatic carotid artery disease.

Proximal Embolic Protection Devices in Complicated Carotid Artery Stenting

The most frequent complication during carotid artery stenting (CAS) is intraoperative distal embolization. Three categories of embolic protection devices (EPDs) are routinely used through a transfemoral or transcervical approach: distal occlusion devices, distal EPDs with flow preservation using filters, and the proximal occlusive protective systems. We report the case of the internal carotid artery (ICA) plaque rupture during CAS using a proximal EPD (the Mo.Ma system; INVATEC), treated with immediate surgery. The proximal occlusive protective system permitted the common carotid artery and ICA endoclamping for the time necessary to prepare the patient for the carotid endarterectomy. The EPDs should always be chosen considering the patient's and lesion's characteristics. This knowledge allows their use even as "bridge" endovascular devices.