Carotid angioplasty under cerebral protection with the percusurge guardwire system

Proximal versus distal protection: dissecting clinical trials

Carotid artery stenting (CAS) is a valid alternative to conventional carotid endarterectomy for treatment of carotid artery stenosis. Distal embolization of atherosclerotic debris causing cerebrovascular accidents during CAS has been the most significant concern limiting widespread application of CAS technology. A variety of embolic protection devices (EPDs) with different mechanism of action, have been designed to minimize the risk of major embolization causing stroke and their use is recommended by current guidelines. Two general types of EPDs are available: proximal protection devices (PPDs) and distal protection devices (DPDs). However, there is no convincing clinical evidence of the clinical superiority of one device over another. This review will examine the different types of available devices and also innovative devices and techniques, including strengths and weaknesses of each, and present the available evidence and rationale for their routine use during CAS.

Use of Embolic Protection Devices in Peripheral Interventions

The use of embolic protection devices (EPDs) when treating coronary saphenous vein bypass grafts, performing carotid arterial stenting and treating acute coronary syndromes is well accepted. We will review currently available devices and approaches to reduce distal embolisation, first discussing their uses in carotid interventions and then in vertebral and peripheral vascular interventions.

Secondary Prevention of Ischemic Cerebrovascular Disease. What Is the Evidence?

Patients who had a transient ischemic attack or stroke are at increased risk of experiencing recurrent cerebrovascular events. For this reason, secondary prevention of ischemic cerebrovascular disease is essential. Several modifiable, lifestyle-associated risk factors have been implicated, such as physical activity, smoking, and alcohol consumption. Established and emerging vascular risk factors are associated with an increased risk of stroke. Pharmacologic treatment, including the use of antiplatelet, antihypertensive, and lipid-lowering agents, has also been shown to reduce the risk of secondary cerebrovascular events. Surgical intervention, either open or endovascular, may be the preferred therapeutic option in well-defined subsets of patients. It is important to establish specific measures for the early detection and prevention of recurrent cerebrovascular disease. Therefore, further research and greater awareness in this field are needed.

Protected Carotid Artery Stenting and Angioplasty via Transfemoral versus Transcervical Approaches

This prospective cohort study was taken to determine whether transcervical carotid artery stenting (CAS) with internal carotid artery (ICA) flow reversal is associated with a lower incidence of embolization and femoral access complication when compared with protected, transfemoral CAS in selected, high-risk patients. From 2002 to October 2004, the authors performed 55 carotid stentings and angioplasties. Among the 24 cases via transfemoral approach, 1 developed transient ischemic attack (TIA), 1 stroke, 1 asystolic cardiac arrest, 2 groin hematoma, 2 technical failure, and 1 restenosis. Among the 31 cases via transcervical approach, 2 patients developed TIAs, 4 bradycardia, 2 cervical hematoma, and 3 technical failures leading to open conversion and carotid endarterectomy. Transcervical CAS with ICA flow reversal eliminates the risk of aortic arch emboli, provides cerebral protection during predeployment manipulation across the carotid lesion, negates preprocedure mapping of the aortic arch configuration, and surpasses difficult aortic arch or transfemoral access.

Design and development of mechanical embolic protection devices

Carotid angioplasty and stenting (CAS) is rapidly becoming an acceptable alternative to carotid endarterectomy in many patients. Much of the success of CAS is credited to advances in equipment dedicated to this minimally invasive approach. Lower profile delivery systems, tapered stent designs and most importantly, development of mechanical cerebral embolic protection devices (EPDs) have contributed to a reduction in periprocedural neurological complications that now rival results of carotid endarterectomy. Despite a lack of level one evidence in support of EPDs, a meta-analysis as well as two recent institutional reports of CAS with and without EPDs suggest a reduced stroke risk when a mechanical protection device is incorporated as part of the procedure. Since the original description by Theron and colleagues, embolic protection systems are markedly improved in ease of use and effectiveness. The three primary groups of EPDs are distal balloon occlusion, distal filtration and proximal occlusion. Although the ideal EPD has yet to materialize, this review provides insight into current design systems and the accompanying strengths and weaknesses of each.

Intravascular ultrasound: principles and cerebrovascular applications

Intravascular sonography is a valuable tool for the morphologic assessment of coronary atherosclerosis and the effect of pharmacologic and nonpharmacologic interventions on the progression or stabilization of atherosclerosis. An analysis of the different modes, applications, and limitations is provided on the basis of review of existing data from multiple clinical case studies, trials, and mechanistic studies. Intravascular sonography has been used to assess the outcomes of different percutaneous interventions, including angioplasty and stent implantation, and to provide detailed characterization of atherosclerotic lesions, aneurysms, and dissections within the cerebrovascular circulation. Evolution of intravascular sonographic technology has led to the development of more sophisticated diagnostic tools such as color-flow, virtual histology, and integrated backscatter intravascular sonography. The technologic advancement in intravascular sonography has the potential of providing more accurate information prior, during, and after a medical or endovascular intervention. Continued assessment of this diagnostic technique in both the intracranial and extracranial circulation will lead to increased use in clinical practice with the intent to improve outcomes.

Recurrent subacute in-stent restenosis after carotid artery stenting due to plaque protrusion

A 70-year-old male presented with transient ischemic attacks manifesting as right hemiparesis and motor aphasia due to severe left cervical internal carotid artery stenosis. Carotid artery stenting (CAS) using a flow-reversal system was performed without complications. However, the patient exhibited transient right hemiparesis and motor aphasia 10 days after CAS. Emergent angiography demonstrated in-stent restenosis. In-stent percutaneous transluminal angioplasty and CAS were performed successfully using a distal protection system. However, duplex ultrasound scanning revealed progressive in-stent restenosis, 3 and 6 days after the re-treatment. Emergent angiography again demonstrated in-stent restenosis. Urgent stent removal and carotid endarterectomy were performed. Plaque had prolapsed through the stent. Histological examination revealed that the specimen was mainly plaque consisting of cholesterol crystals and macrophages. The patient was able to return to independent life without neurological deficit. Repeated endovascular surgery with appropriate antiplatelet and anticoagulation therapy should be attempted initially to treat in-stent restenosis. Endarterectomy with stent removal should be considered as a rescue option, especially if plaque protrusion is identified.

Distal embolic protection during percutaneous coronary intervention in patients with acute coronary syndromes: The RUBY study

OBJECTIVE

To assess the safety and feasibility of the GuardWire system as an embolic protection device during percutaneous coronary intervention (PCI) in acute coronary syndromes (ACS).

BACKGROUND

Distal embolization occurs in approximately 15% of patients after primary angioplasty and is associated with reduced myocardial reperfusion, more extensive myocardial damage and a poor prognosis. Distal embolic protection could reduce the rate of embolic complications and improve outcome.

METHODS

329 patients (mean age 60+/-12 years) were included: 278 (84.5%) with ST-elevation myocardial infarction (STEMI), 50 (15.2%) with unstable angina/non-STEMI and 1 (0.3%) with post-infarction angina. Primary endpoint was the incidence of major adverse cardiac events (MACE) at 30 days. Secondary endpoints were the magnitude of ST-segment resolution at 90 and 180 min post-procedure, myocardial blush grade, and angiographically visible distal emboli.

RESULTS

The GuardWire system was successfully positioned in 99% of patients. Complete ST-elevation resolution (>70%) was observed in 28.5% immediately post-procedure, and in 35.4% and 41.6% at 90 and 180 min post-procedure. TIMI-3 flow grade was achieved by 89.8% of patients after intervention and mean corrected TIMI frame count was 20.2+/-13.2. Grade-3 myocardial blush was seen in 47.7% of patients and distal emboli were angiographically visible in 7.4%. Incidence of MACE at 30 days was 3.3% (death 1.2%; Q-wave MI 0.3%; non-Q-wave MI 0.3%; coronary artery bypass graft 0.6%; repeat PCI 0.9%).

CONCLUSION

The GuardWire system was successfully positioned in nearly all patients without complications. The use of this embolic protection device in ACS patients undergoing PCI was associated with low rates of distal embolization and 30-day MACE.

Double-Wire Technique in Balloon-Protected Carotid Artery Stenting

OBJECTIVES

To evaluate the safety and efficacy of a double-wire technique in carotid artery stenting (CAS) with a distal occlusion balloon system, PercuSurge GuardWire.

METHODS

Fifty-one consecutive patients with 53 de novo lesions were scheduled to undergo balloon-protected CAS with the "double-wire technique," the use of two wires, one for independent predilatation and the other for stent implantation.

RESULTS

Fifty consecutive patients underwent a total of 52 balloon-protected CAS except for 1 patient with one lesion that could not be accessed. The use of a 1.5-mm coronary balloon was necessary in only 2 cases (3.8%) to let the PercuSurge GuardWire cross critically stenotic lesions. The placement of the PercuSurge GuardWire into the internal carotid artery was successful in all cases. Technical success was obtained in all cases. Fifty lesions (96.2%) were treated with one inflation of the distal occlusion balloon during the entire procedure consisting of predilatation, stent implantation, and aspiration, and among them three lesions (5.8%) required postdilatation. The mean occlusion time of cerebral blood flow for 50 lesions was 266 +/- 37 seconds. Out of 50 procedures, 45 (90.0%) had occlusion times of 300 seconds or less. Neurological intolerance requiring intravenous anesthesia was seen in 4 cases (7.7%) and periprocedural neurological complication in 2 cases (3.8%).

CONCLUSIONS

The "double-wire technique" is safe and effective for the shortening of occlusion time during predilatation, stent implantation, and aspiration, leading to satisfactory technical and clinical outcomes, in most cases. This technique should be considered for balloon-protected CAS using the PercuSurge GuardWire.

Intracranial Hemorrhage After Carotid Angioplasty:A Pooled Analysis

PURPOSE

To use a pooled analysis of the literature to find the incidence of and characteristics common to intracranial hemorrhage (ICH) associated with carotid artery stenting (CAS).

METHODS

A search of the English-language literature (1996-2005) was performed in PubMed to find cases of CAS-associated ICH. Information was derived from the identified case studies in 5 categories and 19 aspects: (1) incidence of CAS-associated ICH; (2) demographic data (sex, age, symptom presentation, and presence of preexisting hypertension); (3) imaging data (side of lesion, degree of maximal stenosis, lesion location, status of the contralateral carotid artery, collateral circulation, and preprocedural imaging features); 4) procedure-related characteristics (antithrombotic medication, use of cerebral protection devices, residual stenosis, symptoms, interval from the procedure to ICH, type of ICH, and blood pressure changes); and (5) clinical outcome.

RESULTS

Fifty-four cases of CAS-associated ICH were reviewed: 51 cases from 36 published articles and our own 3 cases. The incidence of CAS-associated ICH was 0.63% (95% CI 0.38% to 0.97%) in studies consisting of >100 cases, which was significantly lower (p<0.0001) than that of case series consisting of <100 cases (2.69%, 95% CI 1.75% to 3.94%). Distinctive features included symptomatic lesions, severe stenosis (> or =90%), maximal stenosis in the internal carotid artery (ICA) distal to the bifurcation, and preexisting cerebral infarction.

CONCLUSION

The incidence of CAS-associated ICH was significantly lower in series consisting of >100 cases. More caution should be directed toward patients with symptomatic lesions, severe stenosis, maximal ICA stenosis distal to the carotid bifurcation, and preexisting cerebral infarction.

Transcranial Doppler monitoring during stenting of the carotid bifurcation: evaluation of two different distal protection devices in preventing embolization

PURPOSE

To compare the efficacy of 2 emboli protection devices in preventing embolization during carotid artery stenting (CAS).

METHODS

The GuardWire distal occlusion system (n=19) and the distal FilterWire EX (n=12) were compared in 31 consecutive patients (24 men; mean age 71+/-10 years) monitored with transcranial Doppler for microembolic signals before, during, and after CAS. The choice of the protection device was based on availability and on the patency of the contralateral carotid artery.

RESULTS

The baseline characteristics were similar in the patients treated under protection from either device. Placement and retrieval of the protection device, stenting, and postdilation were technically successful in all patients. Two patients suffered a transient ischemic attack shortly after the procedure; no other adverse cardiovascular events occurred at 30 days. Compared to the GuardWire, the use of the FilterWire was associated with more microembolic signals during stent deployment (77.4+/-33.5 versus 1.07+/-1.94, p<0.0001), postdilation (63.9+/-21.0 versus 2.06+/-2.58, p<0.0001), and retrieval of the protection device (21.4+/-15.4 versus 10.9+/-8.3, p=0.051). Consequently, the total amount of microembolic signals during the procedure was higher when the filter device was employed (183.0+/-42.1 versus 31.7+/-12.0, p<0.0001).

CONCLUSION

The distal occlusion device appears to be more effective than the filter in reducing distal embolization detected by transcranial Doppler monitoring.

Comparison of embolization protection device-specific technical difficulties during carotid artery stenting

BACKGROUND

Embolic protection devices (EPDs) consisting of an internal carotid artery (ICA) filter or balloon occlusion are typically used during carotid artery stenting (CAS). This study compares the technical difficulties encountered using these two types of EPD.

METHODS

A retrospective review was conducted of patients undergoing CAS using a balloon occlusion EPD (balloon group: PercuSurge GuardWire) or filter EPD (filter group: Accunet, AngioGuard, or FilterWire). Complications were defined as minor stroke, National Institutes of Health (NIH) stroke scale <3; major stroke, NIH stroke scale > or =3; transient ischemic attack (TIA), reversible focal neurologic impairment; technical, reversible neurologic compromise during EPD deployment, inability to cross lesion, ICA spasm requiring treatment, EPD-related factors that prolonged CAS.

RESULTS

CAS (n = 141) was performed in 133 patients (82% men) with a mean age of 72 of years. Comorbidities included diabetes, 35%; coronary artery disease, 75%; hypertension, 82%; and renal insufficiency, 15%. Indication was previous cerebrovascular accident in 10%, TIA in 29%, and asymptomatic >80% stenosis in 61%. Primary lesions were treated in 83% vs restenosis in 17%. The 30-day event rate was 1.4% major stroke, 2.1% minor stoke, 1.4% myocardial infarction, and 0.7% death. The overall combined 30-day stroke, death, and myocardial infarction rate was 5.6%. The 30-day stroke and death rate was 4.0% in the balloon group (n = 99) and 4.6% in the filter group (n = 42, P = .51). EPD-related technical difficulties occurred in 15% of the balloon group and 31% of the filter group (P < .05). Technical difficulties included a 10% incidence of reversible neurologic compromise during balloon deployment compared with 0% in the filter group (P = .002) and 12% incidence of inability to cross the lesion before predilation in the filter group compared with 0% in the balloon group (P = .001).

CONCLUSIONS

During CAS, both balloon occlusion and filter devices provide acceptable results and appear complimentary. Filters can be used preferentially to avoid a 10% incidence of reversible neurologic compromise associated with balloon occlusion, except in critically narrowed or tortuous lesions when balloon occlusion may be preferred because of a 12% need for unprotected predilatation with filters.

Current status of carotid artery stenting

This Clinical Update summarizes the results of larger case series, industry-sponsored registries, and randomized trials of carotid artery stenting (CAS). In >20 case series that studied >24,000 patients undergoing CAS, 51% of patients were symptomatic, most procedures (97%) resulted in successful stent deployment, and 30-day stroke rates varied from 1% to 8%, with a trend toward lower rates as experience and embolic protection device (EPD) use increased. In 12 industry-sponsored registries (none were published in peer-reviewed journals), 30-day stroke rates varied from 2% to 7%, and 30-day combined adverse events, including stroke, death, and myocardial infarction, were 3% to 9%. More than 12 randomized trials comparing CAS and carotid endarterectomy (CEA) have been initiated since 1998. Results have varied over time, depending on the population studied and the technology used. However, the largest and most recent results of the completed SAPPHIRE trial in high-risk patients undergoing CAS with the use of EPDs demonstrated that CAS is at least not inferior to CEA, with a 1-year combined adverse event rate of 12% for CAS and 20% for CEA (P = .05). Other ongoing trials will address not only whether CAS could be superior to CEA in high-risk patients but also, more importantly, whether CAS is beneficial in other subgroups, such as low-risk and asymptomatic patients.

Successful Recanalization by In-Stent Percutaneous Transluminal Angioplasty With Distal Protection for Acute Carotid Stent Thrombosis-Case Report-

A 71-year-old male presented with severe left cervical internal carotid artery stenosis manifesting as repeated transient ischemic attacks consisting of right hemiparesis and motor aphasia. Carotid artery stenting (CAS) under distal protection was performed to prevent further ischemic events. This procedure was uneventful. However, the patient exhibited progressive right hemiparesis and motor aphasia 3 days after CAS. Emergent angiography revealed carotid artery occlusion due to in-stent thrombosis. In-stent percutaneous transluminal angioplasty (PTA) was performed under distal protection. The carotid artery was recanalized with small residual thrombus. The neurological deficits almost completely disappeared after PTA. Follow-up angiography 9 months after stenting showed restenosis but no in-stent thrombosis. Carotid thrombosis after CAS can be resolved by in-stent PTA under distal protection and subsequent treatment with antithrombotic agents.

Intravascular ultrasound identification of intraluminal embolic plaque material during carotid angioplasty with stenting

INTRODUCTION

Carotid angioplasty with stenting (CAS) has evolved as a viable method for treating patients at high risk for carotid endarterectomy. Strokes complicating CAS are most commonly caused by the liberation and distal embolization of embolic material from plaque during the procedure.

METHODS

CAS with distal embolic protection (DEP) was performed using the assistance of intravascular ultrasound (IVUS) in a 68-year-old man with asymptomatic carotid artery stenosis. Evaluation of the plaque pretreatment was performed using virtual histology software. IVUS evaluation was also performed after prestent angioplasty, stenting, and poststent angioplasty.

RESULTS

Initial degree of angiographic stenosis was 78.9%. Final degree of stenosis was 15.7%. By IVUS, stenosis by minimum lumen diameter and minimum lumen area were 75.6% and 93.4% pretreatment, respectively, and 42.2% and 47.1% posttreatment, respectively. An intraluminal lesion was noted in the distal aspect of the stent after poststent angioplasty but before DEP device removal. Ultrasonographic characteristics of the intraluminal defect were consistent with ruptured plaque material. Angiographic runs failed to demonstrate the lesion. A repeat IVUS run performed approximately 10 min later failed to depict the lesion, suggesting that distal embolization had occurred. Embolic material was noticed in the DEP device after removal. The patient did not experience any ischemic neurological symptoms.

CONCLUSIONS

IVUS can identify intraluminal plaque material, which may be a precursor for embolism and delayed ischemic events after CAS. IVUS may allow for treatment before distal embolization of plaque material. Virtual histology IVUS software may help to identify carotid lesions at higher risk for significant embolization during CAS.

Assessment of short-term outcomes for protected carotid angioplasty with stents using recent evidence

BACKGROUND

Carotid artery stenosis is an important risk factor and etiology of stroke. Carotid endarterectomy (CEA) is the gold standard for the treatment of carotid artery stenosis; however, there are potential benefits to adopting the use of carotid artery stenting (CAS) with protection devices. A number of large protected CAS (PCAS) trials are underway, but final results are still several years away. In the interim, numerous PCAS studies have recently been published, and the aim of this study was to combine the published results and examine the outcomes and safety of PCAS.

METHODS

Electronic, manual, and bibliographic searches of PubMed and PreMedline were conducted. Proportion differences were calculated for the periprocedural (30-day) outcomes of any stroke and any stroke or death.

RESULTS

More than 400 articles were identified. Only 26 studies met the inclusion criteria, resulting in the inclusion of 2,992 patients treated with PCAS. Within this patient group, the pooled perioperative PCAS rate of any type of stroke was 2.4% +/- 0.3% (95% confidence interval [CI]). The 30-day minor stroke rate was 1.1% +/- 0.2% (95% CI), and the 30-day major stroke rate was 0.6% +/- 0.2% (95% CI). The 30-day mortality rate was 0.9% +/- 0.4% (95% CI).

CONCLUSION

This study demonstrates relatively low rates of reported perioperative adverse events in PCAS. Selective use of PCAS to treat carotid artery stenosis in those at highest risk for surgical complications is appropriate until the randomized trials of CEA vs PCAS provide concurrent short- and long-term outcome data.

Bilateral brachial artery occlusion decreases internal carotid artery volume flow: a simple adjunct for cerebral protection?

PURPOSE

To investigate if a decrease in internal carotid artery (ICA) blood flow occurs with bilateral brachial artery occlusion (BBO), which may improve the effectiveness of cerebral protection devices during carotid interventions.

METHODS

Thirty-two asymptomatic patients (21 men; mean age 67 years) with carotid atherosclerosis between 15% and 79% were enrolled in the study. Carotid duplex ultrasound was followed by volume flow rate (VF) determination in the right ICA, external carotid (ECA), and vertebral arteries. After baseline values were obtained, BBO was induced by bilateral arm pressure cuff inflation to 30 mmHg over the systolic pressure for no more than 3 minutes. VF measurements were repeated.

RESULTS

Seventeen patients (responders) had an ICA VF decrease from 406+/-109 mL/min (+/-SD) to 303+/-90 mL/min (p=0.005), while 15 patients (nonresponders) had no significant change in their ICA VF (340+/-192 versus 447+/-267 mL/min, p=0.22). In responders, ECA VF increased (190+/-65 to 232+/-125 mL/min), as did vertebral VF (77+/-53 to 95+/-60 mL/min; p>0.05). The ratio of ICA/ECA VF dropped from 2.13 to 1.31 in responders, but did not change in nonresponders. No patient exhibited any neurological symptoms during the study. Post cuff volume flows approximated baseline values. Cerebral magnetic resonance angiograms obtained in 10 responders revealed a complete circle of Willis in 8 (80%), while only 1 (16%) of 6 nonresponders had a complete pathway.

CONCLUSIONS

A transient decrease in ICA VF, with concomitant elevations of the ECA and vertebral VFs, occurs with occlusion of the brachial arteries in the setting of a complete circle of Willis. Since no flow reversal occurs, this maneuver is insufficient to provide complete cerebral protection, but it may improve the effectiveness of cerebral protection devices and serve as an adjunctive maneuver in selected cases. Furthermore, changes in ICA VF may prove to be a noninvasive test for evaluating the integrity of the circle of Willis.

Cerebral Embolic Protection

Carotid angioplasty and stenting (CAS) is rapidly evolving into a viable alternative to carotid endarterectomy (CEA). This has been possible due to advances in endoluminal equipment and the development of mechanical cerebral embolic protection devices. Theoretically, these various devices reduce the occurrence of distal embolization into the intracranial circulation and thereby minimize the clinical consequence of a cerebrovascular accident. Embolic protection systems are currently classified into three main categories depending on the mechanism: 1) distal occlusion; 2) distal filtration; and 3) proximal occlusion. This review will provide a framework with regard to these devices with some specific examples cited.

Endovascular treatment of the subclavian artery: Stent implantation with or without predilatation

The endovascular treatment of subclavian artery (SA) lesions is less invasive than open surgical repair, with a low rate of complications. We report our experience in 89 subclavian obstructive lesions (n = 86) treated with stenting: 76 (85.3%) stenoses and 13 (14.6%) total occlusions. The left side was most frequently involved (83.1%), localized at the prevertebral segment in 91%. Technical success was obtained in 83 (93.3%) cases, 100% in stenotic lesions and 53.8% in total occlusions. There were nine global complications (10.1%): five (5.6%) at site of puncture, two distal embolization (2.2%), and two (2.3%) major events. The long-term follow-up was 3.51 +/- 1.98 years, during which time 13 (16.8%) restenoses and 2 (2.6%) reocclusions were noted. Subgroup analysis of patients with stenting after predilatation versus direct stenting technique showed in-hospital complications only in the first group, with a restenosis rate of 28.5% vs. 4.7%, respectively (P = 0.003). We consider stenting for SA obstructive lesions the first therapeutic option.