Procedural safety and short-term outcome of ambulatory carotid stenting

Predisposing Factors and Management of Hemodynamic Depression Following Carotid Artery Stenting

Carotid artery stenting (CAS) involves dilatation of carotid bulb which can trigger a series of neuronal responses resulting in hemodynamic depression that might influence the outcome of the procedure. This is a frequent but underdiagnosed complication of CAS. Although it is mild, transient and self-limiting in majority of cases, it can result in significant morbidity and mortality if persistent. Neurologists should be aware of the predisposing factors and management of this common complication. In patients who present with stroke following carotid stenting, neurologists should be aware of hypoperfusion secondary to hemodynamic depression as a cause of stroke apart from the stent thrombosis and occlusion.

Direct carotid puncture in acute ischaemic stroke intervention

Endovascular intervention for acute ischaemic stroke care is mostly performed in older patients, often with unfavourable aortic and supra-aortic anatomy, as well as cardiovascular comorbidities. A significant subset of them may benefit from transcervical access as the initial approach for mechanical thrombectomy. In fact, direct carotid artery puncture in these cases has the advantage to bypass the anatomical obstacles and achieve faster reperfusion. Caution is advised when common carotid artery access is pursued in order to avoid adverse events, including haematoma formation, iatrogenic arterial dissection and sheath kinking. In spite of potential complications, direct carotid puncture in acute ischaemic stroke intervention overcomes challenging angioarchitecture and may reduce the rate of poor clinical outcomes associated with delayed revascularisation in certain cases.

Brain Injury Secondary to Carotid Intervention

Causes of brain injury during endovascular carotid intervention are protean. Mechanisms of injury include embolic and hemodynamic events, acute carotid occlusions occurring through a variety of means, and the relatively rare contrast-induced encephalopathy.

Embolic injury may result from micro- and macroembolization and most commonly causes ischemic stroke when sufficiently severe. Hemodynamic injury may proceed from hemodynamic depression and hypoperfusion (which may result in watershed infarction) or the hyperperfusion syndrome, which may, if severe, result in hemorrhagic stroke.

Embolic and dynamic causes of stroke may either occur intraprocedurally or at a variable time after stent placement and may be co-related. Impaired clearance of emboli due to relative hypoperfusion may exacerbate their clinical relevance. Other causes of stroke include acute carotid occlusions, which most commonly occur procedurally due to flow-limiting spasm, acute dissection, and, if a filter-type cerebral protection device has been used, filter occlusion due to a large trapped embolic load. These scenarios may result in stroke if not recognized and dealt with appropriately. Acute stent thrombosis may occur within 24 hours of the procedure as a result of adverse hemodynamic factors or suboptimal patient response to procedural heparin and antiplatelet agents, or it may occur after the procedure, again perhaps as a result of suboptimal response to antiaggregate drugs.

Carotid Duplex Velocity Criteria Revisited for the Diagnosis of Carotid In-Stent Restenosis

Carotid percutaneous transluminal angioplasty/stenting has become an accepted treatment modality for carotid artery stenosis in high-risk patients. There has been an ongoing debate regarding which duplex ultrasound (DUS) criteria to use to determine the rate of in-stent restenosis. This prospective study revisits DUS criteria for determining the rate of in-stent restenosis. In analyzing a subset of 12 patients (pilot study) who had both completion carotid angiography and DUS within 30 days, 10 patients with normal post-stenting carotid angiography (< 30% residual stenosis) had peak systolic velocities (PSVs) of the stented internal carotid artery (ICA) of ≤ 155 cm/s and two patients with ≥ 30% residual stenosis had internal carotid artery (ICA) PSVs of > 155 cm/s. Eighty-three patients who underwent carotid stenting as part of clinical trials were analyzed. All patients underwent post-stenting carotid DUS that was done at 1 month and every 6 months thereafter. PSVs and end-diastolic velocities of the ICA and common carotid artery were recorded. Patients with PSVs of the ICA of > 140 cm/s underwent carotid computed tomographic (CT) angiography. The perioperative stroke rate was 1.2%. When the old DUS velocity criteria for nonstented carotid arteries were applied, 54% of patients had ≥ 30% restenosis (PSV of > 120 cm/s), but when our new proposed DUS velocity criteria for stented arteries were applied (PSV of > 155 cm/s), 33% had ≥ 30% restenosis at a mean follow-up of 18 months ( p = .007). The mean PSVs for patients with normal stented carotid arteries based on CT angiography, were 122 cm/s versus 243 cm/s for ≥ 30% restenosis and 113 cm/s versus 230 cm/s for ≥ 30% restenosis based on our new criteria. The mean PSVs of in-stent restenosis of 30 to < 50%, 50 to < 70%, and 70 to 99%, based on CT angiography, were 205 cm/s, 264 cm/s, and 435 cm/s, respectively. Receiver operating curve analysis demonstrated that an ICA PSV of > 155 cm/s was optimal for detecting ≥ 30% in-stent restenosis, with a sensitivity of 100%, a specificity of 90%, a positive predictive value of 74%, and a negative predictive value of 100%. The currently used carotid DUS velocity criteria overestimated the incidence of in-stent restenosis. We propose new velocity criteria for the ICA PSV of > 155 cm/s to define ≥ 30% in-stent restenosis.

Carotid Endarterectomy: A Review

Background:

Since the validation of carotid endarterectomy (CEA) as an effective means of stroke prevention, there has been renewed interest in its best indications and methods, as well as in how it compares to carotid angioplasty and stenting (CAS). This review examines these topics, as well as the investigation of carotid stenosis and the role of auditing and reporting CEAresults.

Investigation:

Brain imaging with CTor MRI should be obtained in patients considered for CEA, in order to document infarction and rule out mass lesions. Carotid investigation begins with ultrasound and, if results agree with subsequent, good-quality MRAor CTangiography, treatment can be planned and catheter angiography avoided. An equally acceptable approach is to proceed directly from ultrasound to catheter angiography, which is still the gold-standard in carotid artery assessment.

Indications:

Appropriate patients for CEA are those symptomatic with transient ischemic attacks or nondisabling stroke due to 70-99% carotid stenosis; the maximum allowable stroke and death rate being 6%. Uncertain candidates for CEA are those with 50 - 69% symptomatic stenosis, and those with asymptomatic stenosis ≥ 60% but, if selected carefully on the basis of additional risk factors (related to both the carotid plaque and certain patient characteristics), some will benefit from surgery. Asymptomatic patients will only benefit if surgery can be provided with exceptionally low major complication rates (3% or less). Inappropriate patients are those with less than 50% symptomatic or 60% asymptomatic stenosis, and those with unstable medical or neurological conditions.

Techniques:

Carotid endarterectomy can be performed with either regional or general anaesthesia and, for the latter, there are a number of monitoring techniques available to assess cerebral perfusion during carotid cross-clamping. While monitoring cannot be considered mandatory and no single monitoring technique has emerged as being clearly superior, EEG is most commonly used. “Eversion” endarterectomy is a variation in surgical technique, and there is some evidence that more widely practiced patch closure may reduce the acute risk of operative stroke and the longer-term risk of recurrent stenosis.

Carotid angioplasty and stenting:

Experience with this endovascular and less invasive procedure grows, and its technology continues to evolve. Some experienced therapists have reported excellent results in case series and a number of randomized trials are now underway comparing CAS to CEA. However, at this time it is premature to incorporate CAS into routine practice replacing CEA.

Auditing:

It has been shown that auditing of CEA indications and results with regular feed-back to the operating surgeons can significantly improve the performance of this operation. Carotid endarterectomy auditing is recommended on both local and regional levels.

Comparison of mid-term outcomes of carotid artery stenting for moderate versus critical stenosis

INTRODUCTION

Little is known about the prognosis of moderate versus critical carotid stenosis treated by carotid artery stenting (CAS).

MATERIAL AND METHODS

This was a retrospective analysis of a single-centre registry including 271 consecutive patients (69 ±9 years, 87% at high risk for surgery), in whom 308 procedures were performed. The study included both symptomatic (≥ 50% carotid artery stenosis) and asymptomatic (≥ 70% carotid artery stenosis) patients. The primary endpoint was the rate of adverse events during follow-up (range 1-48 months), defined as all-cause death or stroke.

RESULTS

We treated 115 critical and 193 moderate stenoses and implanted 318 stents (56% with closed cell design). Embolic protection systems were used in 296 cases (96%). The technical success rate was 98.2% in the critical stenoses group and 99% in the moderate group (NS). During follow-up, the incidence of the primary endpoint was 12.9% (13 pts) in the critical stenoses group and 14.7% (25 pts) in the moderate stenoses group (estimated 3-year freedom from death/stroke was 0.844 vs. 0.812; log-rank test p = 0.983). Left ventricular ejection fraction < 40%, significant contralateral carotid artery occlusion or stenosis and renal insufficiency were identified as significant predictors of the primary endpoint (p < 0.03).

CONCLUSIONS

Carotid artery stenting with embolic protection systems in patients at high risk for carotid endarterectomy is safe. Patients with initially moderate and critical stenoses have an identical mid-term prognosis with regard to death and stroke.

Predictors and Timing of Neurological Complications Following Intracranial Angioplasty and/or Stent Placement

BACKGROUND:

Transient or permanent neurological complications can occur in the periprocedural period following intracranial angioplasty and/or stent placement. Which patients are at risk and the time period for maximum vulnerability among those who undergo intracranial angioplasty and/or stent placement have not been formally studied.

OBJECTIVE:

To assess the predictors and timing of neurological complications following intracranial angioplasty and/or stent placement in the periprocedural period in a consecutive series of patients.

METHODS:

We reviewed medical records and angiograms of consecutive patients treated with intracranial angioplasty and/or stent placement in 3 academic institutions. We evaluated the effect of demographic, clinical, intraprocedural, and angiographic risk factors on subsequent development of periprocedural neurological complications. Periprocedural neurological complications were defined as new or worsening transient or permanent neurological complications that occurred during or within 1 month of the procedure. We also recorded the timing and nature of neurological complications in the periprocedural period.

RESULTS:

A total of 92 patients were included in the study (mean age ± standard deviation: 59 ± 14 years; 59 were men). The overall rate of in-hospital neurological complications was 9.8% (9 of 92 patients). Eight out of 9 neurological complications occurred either during the procedure or within 6 hours thereafter. Presence of diabetes mellitus (P = .003) and use of balloon-expandable stent (P = .09) were associated with periprocedural neurological complications. The degree of pre- and post-procedure stenosis, morphological appearance, and length of lesion were unrelated to periprocedural complications.

CONCLUSION:

Patients with diabetes mellitus and those treated with balloon expandable stents are at high risk for periprocedural neurological complications. The first 6 hours following intracranial angioplasty and stent placement represent the period of highest risk.

Can periprocedural hypotension in carotid artery stenting be predicted? A carotid morphologic autonomic pathologic scoring model using virtual histology to anticipate hypotension

SUMMARY

Periprocedural hypotension, which frequently occurs during carotid artery stenting (CAS), is an important risk factor for complications such as stroke or death after CAS. To determine if a scoring model can be established to predict periprocedural hypotension (systolic blood pressure < or = 90 mm Hg) and prolonged periprocedural hypotension (requiring vasopressor for > 3 hours) in CAS, we conducted a prospective cohort study of patients undergoing interventional treatment of cervical carotid artery stenosis in an urban tertiary referral hospital from April 2006 to April 2007. Forty-eight stenotic lesions in 45 consecutive patients treated with CAS were included in the study. Multivariate analysis showed three independent risk factors of periprocedural hypotension; "fibrous plaque on Virtual Histology" (P = 0.029), "stenotic lesion involving both the common carotid artery and internal carotid artery on angiogram" (P = 0.004), and "patients without history of diabetes mellitus" (P = 0.020). Further, "distance between carotid bifurcation and point of minimum lumen size < or = 10 mm on angiogram" (P = 0.003) was an independent risk factor of prolonged periprocedural hypotension. Carotid morphologic autonomic pathologic score (carotid MAPS), determined by adding one point for each of those risk factors (total 0 to 4), had good discrimination for both periprocedural hypotension (area under receiver operating characteristic curve: ROC AUC = 0.876; SE 0.053) and prolonged periprocedural hypotension (ROC AUC = 0.811; SE 0.066). Carotid MAPS is useful for predicting periprocedural hypotension and prolonged periprocedural hypotension during CAS.

An evaluation of immediate sheath removal and use of the Angio-Seal vascular closure device in neuroradiological interventions

We set out to assess the effect of using an arteriotomy closure device in patients at high risk of access site complications. One-hundred nineteen patients with femoral artery access were prospectively included in five centers in France (56 males, 63 females, age range 20-84 years). The neurointerventional procedures were embolization of intracranial aneurysm (71.4%), carotid angioplasty (11.8%), cerebral angioplasty (1.7%), thrombolysis (0.8%), and other procedures (14.3%). Sheaths were removed and the closure device deployed immediately postprocedure. One patient developed a false aneurysm, and one developed a small hematoma. Neither required treatment. Postdevice deployment bleeding was experienced in three patients (2.5%), requiring minimal management. There were no major complications. Three patients died of causes unrelated to the vessel closure. Patient comfort was 2.2 on a scale of 1 (none) to 10 (severe). The results showed that immediate sheath removal followed by use of the closure device is safe in patients undergoing neurointerventional procedures and offers a low level of patient discomfort. In selected patients, early hospital discharge was possible.

The Relationship Between Plasma MMP-1, -7, -8 and -13 Levels and Embolic Potential During Carotid Endoluminal Intervention

BACKGROUND

Patients undergoing carotid endoluminal intervention are at risk of embolic stroke even with the use of distal protection devices. Matrix metalloproteinases (MMPs) have been implicated as a causal factor in plaque instability leading to spontaneous embolisation. We investigated whether plasma MMP levels correlated with the embolisation during carotid endoluminal intervention.

METHODS

Thirty circumferentially intact carotid endarterectomy specimens were subjected to a standardised angioplasty procedure in a pulsatile ex vivo model. Emboli collected in a series of distal filters were counted and sized. Plasma samples were collected pre-operatively and analysed for MMP-7 and MMP-8 levels using Western immunoblotting. MMP-1 and MMP-13 levels were determined using ELISA. Emboli number and maximum size were correlated with plasma levels of the MMPs using Spearmans rank.

RESULTS

Total MMP-8 levels were related to maximum embolus size (r=0.442, p=0.005) but not emboli number (r=0.342, p=0.052). MMP-1, -7 and -13 were not correlated with either emboli number or with maximum embolus size.

CONCLUSION

Pre-operative plasma MMP-8 levels are related to the size of emboli from plaques during carotid endovascular intervention. Further in vivo studies need to be performed to assess the importance of this finding. There is potential for development of plasma markers to identify those patients at greater risk of embolic stroke during carotid endoluminal intervention.

Evolution of Neuroendovascular Intervention: A Review of Advancement in Device Technology

NEUROENDOVASCULAR SURGERY IS a rapidly evolving field. Each year, numerous improvements are made in the endovascular surgeon's armamentarium. This evolution in technology, which is occurring at a dizzying pace, addresses many of the current limitations of neuroendovascular approaches. The potential to improve the outcomes of our patients is tremendous, particularly because one of the most common and most devastating neurological disorders, ischemic stroke, remains largely untreated. This article presents several of the new technologies that are currently being investigated or are under development and have the potential to lead to major advances in endovascular approaches for the treatment of intracranial and extracranial diseases.

Carotid Angioplasty and Stenting versus Carotid Endarterectomy for Treatment of Asymptomatic Carotid Stenosis: A Randomized Trial in a Community Hospital

OBJECTIVE

Carotid endarterectomy (CEA) is effective in reducing the risk of stroke in individuals with more than 60% carotid stenosis. Carotid angioplasty and stenting (CAS) has been proffered as effective and used in treating individuals with asymptomatic carotid stenosis despite the absence of proven clinical equivalency. This randomized trial was designed to explore the hypothesis that CAS is equivalent to CEA for treating asymptomatic carotid stenosis.

METHODS

A total of 85 individuals presenting with asymptomatic carotid stenosis of more than 80% were selected randomly for CAS or CEA and followed up for 48 months.

RESULTS

Stenosis decreased to an average of 5% after CAS. The patency of the reconstructed artery remained satisfactory regardless of the technique, as determined by carotid ultrasonography. No major complications such as cerebral ischemia or death occurred. Procedural complications associated with CAS (n = 5) were hypotension and/or bradycardia; those concomitant with CEA (n = 3) were cervical nerve injury or complications related to general anesthesia (n = 4). Both procedures were well tolerated in the context of pain and discomfort. Hospital stay was similar in the two groups (mean, 1.1 versus 1.2 d). The occurrence of complications associated with CAS or CEA prolonged hospitalization by 3 days (mean, 4.0 versus 4.5 d). Return to full activity was achieved within 1 week by more than 85% of patients; all returned to their usual lifestyle by 2 weeks. Although hospital charges were slightly higher for CAS, costs were similar.

CONCLUSION

CAS and CEA may be equally effective and safe in treating individuals with asymptomatic carotid stenosis.

Timing and frequency of complications after carotid artery stenting: what is the optimal period of observation?

OBJECTIVE

Currently our standard of practice is that patients undergoing carotid artery stenting (CAS) may be safely discharged on the first day post-procedure. However, many patients are completely independent on the evening of procedure. Therefore we sought to establish the safety and feasibility of same-day discharge by assessing frequency and time of complications in the first 30 days after CAS.

METHOD

Case records for 208 consecutive patients who had undergone CAS from October 1999 to October 2002 were retrospectively reviewed. Excluded were four cases in which combined CAS and carotid endarterectomy was performed to treat synchronous stenosis. Of the remaining 204 cases, involving 201 patients (three patients underwent staged bilateral CAS), 173 (84.8%) were symptomatic and 31 (15.2%) were asymptomatic.

RESULT

Thirty-eight major events or death (inclusive of all neurologic events and any complications that required treatment) were recorded in the first 30 days after CAS, for an event rate of 18.6% per case. These were 7 (3.4%) major access site complications; 18 (8.8%) neurologic events, of which 10 (4.9%) were transient ischemic events and 8 (3.9%) were strokes (including minor, major, and fatal stroke); 8 (3.9%) cardiovascular complications; and five (2.5%) other events. Twenty (52.6%) events occurred in the first 6 hours after CAS, 2 (5.3%) between 6 and 12 hours, 3 (7.9%) between 12 and 24 hours, and 13 (34.2%) 24 hours to 30 days post procedure. Four (2.0%) deaths were recorded in this period, 1 secondary to stroke, 1 from a perforated myocardium from a temporary pacing wire, and 2 from unrelated causes. The 30-days stroke and death rate was 5.4% (11 of 204 patients).

CONCLUSION

Time of complications suggests that outpatient performance of CAS is feasible and safe in selected patients.