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New Approach for Carotid
Angioplasty and Stenting. Benefits
of Cerebral Protection with the
Percusurge Guidewire System:
Immediate and Mid-Term Results
Michel Henry, MD; Isabelle Henry, MD;
Christos Klonaris, MD; Isabelle Masson, MD;
Kiril Tzvetanov, MD; Gérard Ethevenot, MD;
Edmond Le Borgne, MD; Serge Kownator, MD;
François Luizi, MD; Bernard Folliguet, MD
Cardiologie Interventionelle, Policlinique d´Essey-les-Nancy, France
Cerebrovascular accidents occur each year in 500,000 Americans and result in 150,000 deaths and in substantial morbidity (1). Although antiplatelet agents have a continuing role in reducing cerebrovascular risk, randomized controlled trials have shown that a reduction in carotid artery stenosis by carotid endarterectomy (CE) is superior to that of medical therapy alone (2-4).
Carotid endarterectomy, however, has certain limitations. In the North American Symptomatic carotid Endarterectomy Trial (NASCET), 5.8% of patients had perioperative stroke or death (2). In the Asymptomatic Carotid Atherosclerosis Study (ACAS), the perioperative stroke rate was 2.8 % (4). In higher-risk patients, particularly those with severe coronary artery disease, perioperative morbidity and mortality have been reported in up to 18% of patients (1,5-14). Cranial nerve palsies have been reported in up to 27% of patients (1,10). Also, restenosis occurs in 5 to 19% of patients, and scarring from the initial operation can make repeat carotid endarterectomy difficult (9,15). Independent predictors of adverse outcome include contralateral occlusion, previous ipsilateral carotid endarterectomy and combined coronary and carotid artery disease (2,5-14). Further, carotid endarterectomy is limited to the cervical portion of the carotid artery.
Based on the encouraging results obtained in the coronary and peripheral circulation with percutaneous interventional techniques, a natural evolutionary step was their application at the cerebrovascular level. Several recent studies suggest that carotid angioplasty and stenting (CAS) can be performed with a perioperative combined stroke and death rate of 2.9 % to 8.2 % (16-22). Shawl et al. (21) recently showed the safety and efficacy of elective carotid artery stenting in a series of 170 high-risk patients (192 carotid arteries stented). The total 30-day stroke rate was of 2.9% for treated patients or 2.6% for treated arteries. This procedure may prove to be safer, less traumatic and more cost-effective than carotid endarterectomy. Moreover, the risk/benefit ratio may be the greatest in patients at the highest risk for carotid endarterectomy (5,6,12-14). Further, carotid artery stenting is not limited to the cervical portion of the carotid artery.
But embolic stroke, even with a meticulous technique and experienced operators, represents the major drawback of the procedure. The majority of the neurological complications are due to the intra-cerebral embolism of plaque fragments or thrombus during different procedural steps. Cerebral protection devices have been developed to reduce the incidence of embolic events during carotid angioplasty (24).
We, therefore, prospectively examined the outcome of 184 carotid angioplasties and stenting under cerebral protection using a new device, the PercuSurge Guardwire System (PercuSurge Inc., Sunnyvale, CA, U.S.A.), in 167 patients to assess whether this therapy is comparable to historical controls of both carotid endarterectomy and angioplasty without cerebral protection.
Between February 1998 and September 2000, 167 patients (184 carotid stenosis) met the inclusion criteria and underwent carotid angioplasty and stenting under protection using the PercuSurge Guardwire ä device. All patients were required to agree to regular follow-up and sign an informed consent statement.
Patient Selection Criteria
Patients were eligible for the study if they presented a = 70 % diameter stenosis of the internal carotid artery (I.C.A.) documented on an intra-arterial digital substraction angiography and evaluated according to the Nascet criteria (2). Patients were excluded if any of the following occurred: multiple stenosis in the internal carotid artery, intracranial pathology, suspicion of thrombus (presence of filling defects inside the artery at the angiogram in 3 patients), gastro intestinal bleeding in the last six months, hemorrhagic disorders, participation in another study during the last 3 months, and inability to give informed consent.
Description of the protection device
The device described elsewhere (23) briefly consists of three main components:
1. The GuardWire temporary occlusion catheter: a 0.014" or 0.018" wire constructed of hollow nitinol hypotube incorporating into its distal segment an inflatable compliant balloon capable of occluding vessel outflow. The balloon diameter (3-6 mm) is chosen depending on the artery diameter.
2. A Microseal incorporated at the proximal end of the wire, allowing inflation and deflation of the distal Protection Balloon (PB) utilizing a Microseal adapter. The Microseal keeps the elastomeric balloon inflated while allowing catheter exchange at the proximal end similar to commonly used guide wires.
3. The aspiration catheter placed over the GuardWire to aspirate generated debris and flush the I.C.A..
Protected CAS Technique
A 8 or 9F multipurpose guide catheter is initially placed into the common carotid artery (C.C.A.) by femoral approach. The GuardWire is then gently advanced through the guide catheter, the lesion crossed and the marker of the protection balloon placed 2 or 3 cm beyond it. The MicroSeal adapter is then attached and the protection balloon slowly inflated with a fixed volume of dilute contrast, occluding the I.C.A. and deriving vessel outflow towards the External Carotid Artery (E.C.A.). On detaching the Microseal adapter, the occlusion balloon remains inflated. Predilatation of the lesion or direct stenting are then performed under protection. Any generated debris is removed from the I.C.A using aspiration alone or aspiration and flushing techniques.
Two techniques have been used:
- Technique 1: the PB remains inflated during the whole procedure and the aspiration is performed once after stent placement and post-dilatation.
- Technique 2: the PB is deflated between predilatation and stent placement to restore the cerebral flow. Aspiration is performed after each of these two stages.
The technique used depends on the tolerance of the occlusion, the cerebral collateral circulation, the status of the contralateral artery, the duration of the procedure and the technical problems encountered.
In both scenarios the aspiration catheter is advanced over the wire into the dilated area, a 20-cc syringe connected to it to aspirate debris. Additionally, in our initial 40 cases, a flushing of the treated area was performed using saline injections through the guide catheter to "drive" the particles towards the E.C.A.. The injection was performed with an injection pump at a rate of 2 ml/s for 10 sec.
Finally, the Microseal adapter is reattached to the GuardWire, the P.B. deflated allowing normal flow to restore. If the angiographic result is satisfactory, the device is removed.
All patients were prescribed aspirin 250 mg/day indefinitely and received ticlopidine 250 to 500 mg/day or clopidogrel 75 mg/day, for at least two days and preferably one week before the procedure and for one month after it. Unfractionated heparin (5000 IU IV) and Atropine (1mg IV) were routinely administered just after the introducer sheath placement. A temporary pacemaker was never used. Heparin was continued until the following day at doses to keep the activated clotting time (ACT) > 200 sec.. In 5 patients, abciximab was given in conjunction with the procedure, based on clinical judgment due to the presence of subocclusive lesions in 3 patients and suspicion of thrombi during the procedure, after stent placement, in 2 patients. The introducer sheaths were removed after the procedure when the ACT was ≤ 180 sec. and no further anticoagulation was given. Patients were usually discharged the day after the procedure.
A neurological assessment by an independent neurologist using the N-score clinical examination scale (27), baseline blood and chemistry values, coagulation profile, electrocardiogram, brain CT-scan or MRI and duplex studies were routinely performed. Transcranial Doppler was done before and after the procedure but not routinely during the procedure.
During duplex study, a characterization of plaque echodensity was made in a subgroup of 20 patients according to the Nicolaides' method (25-26) which consists in a grey scale analysis of the overall plaque echogenicity. The grey scale median density value (MDV) was determinated for the different plaques. The MDV was compared to the number and the size of the particles released during CAS and the relationship between the degree of stenosis evaluated by the pike systolic velocity and the importance of embolism (number of particles) studied.
Computerized digital substraction angiography with at least two orthogonal projections of the carotid bifurcation and images of the intracranial circulation were performed and recorded for each patient before and after the procedure. The NASCET angiographic criteria (2) were used to calculate the degree of stenosis before and after angioplasty and stenting, with the distal, non tapering portion of the internal carotid artery serving as the reference segment.
During and after carotid artery stenting, neurologic status was continuously monitored by simple contralateral hand-gripping maneuvers.
All patients underwent a neurological examination, a duplex-scan and a CT-scan the day after CAS, a neurological examination and a duplex-scan at day 30 and every 6 months thereafter, an angiogram at 6 months. Any change in neurologic status after CAS required repeated CT brain-scan. Quantitative analysis was performed by an independent observer who did not know the patient outcome.
Study end points
- The primary clinical end points assessed included any major/minor stroke, death or myocardial infarction (MI) within the first 30 days post-procedure. Among them, the peri-procedural complications were defined as any major/minor stroke, death or MI occurring in the early 48 hours.
- The secondary clinical end points were the need of new intervention, angioplasty or endarterectomy at 6 months.
- Angiographic end points were: angiographic success rate, defined as achieving a <30 % residual stenosis, angiographic restenosis, defined as a reduction of the arterial lumen diameter >50 %. The procedural success was defined as a reduction in the stenosis to ≤ 30% and absence of any neurological complication, myocardial infarction or death.
Data collection, statistical methods
Clinical, angiographic and procedural data were prospectively recorded on a standardized form. The clinical and demographic variables collected included age, gender, symptoms, associated cardiac or peripheral artery disease, presence or absence of diabetes mellitus, hypertension, hyperlipidemia, history of smoking, bilateral carotid artery stenosis or occlusion and whether the patient was randomizable into NASCET or ACAS.
All data are expressed as the mean value ± SD or as numbers of patients or percentages for categorical variables.
The comparisons between the type of plaques, the number and the size of particles, between the degree of stenosis and the importance of embolism were performed with regression tests analysis.
The survival curve was drawn on an actuarial basis using the Kaplan-Meier method.
Myocardial infarction: Development of new Q waves on the electrocardiogram (ECG) and/or a creatine kinase elevation to at least twice the normal level, accompanied by above-normal elevation of the MB band.
Transient Ischemic Accident (TIA): A new neurologic deficit that completely resolved within 24 hours.
Minor stroke: A new neurologic deficit that persisted for >24 h, but completely resolved or returned to baseline within seven days. By definition, minor stroke are nondisabling neurologic events.
Major stroke: A new neurologic deficit that persisted after seven days.
Patient characteristics ()
One hundred and eighty four procedures were attempted in 167 consecutive patients (129 males, 38 females, age: 70.5 ± 9.2 years, range: 40-91 years). Seventeen patients had bilateral procedures.
Ninety-three patients were asymptomatic (50.5%), 91 were symptomatic (49.5%). Cardio-vascular risk factors were: hypertension in 125 patients (74.8%), diabetes in 32 (19.2%), hyperlipidemia in 101 (60.5%), smoking in 100 (59.9%) and obesity in 22 (13.2%). Associated diseases were: stable coronary artery disease in 79 patients (47.3%), unstable angina in 7 (4.2%), cardiac failure in 14 (8.4%), peripheral arterial disease in 38 (22.8%), renal artery stenosis in 19 (11.4%), renal insufficiency in 12 (7.2%), respiratory failure in 13 (7.8%). 122 patients (73%) would have been excluded from the NASCET or ACAS entry criteria.
Lesion characteristics ()
One hundred and fifty seven lesions were atherosclerotic, 18 were restenoses (post-surgical: 15, post-angioplasty: 3) and 7 were post-radiation stenosis. One lesion was an inflammatory arteritis and another one a post traumatic aneurysm. The mean percentage of stenosis was 81.5 ± 9.3 % (70 - 99). Mean lesion length was 14.5 ± 6.2 mm (5 - 50) and the mean arterial diameter was: 5.0 ± 1.2 mm (4.1-7.1). Eighty-five lesions (46.2%) were calcified, 135 were ulcerated (73.4%). 87 were hyperechogenic (47.3%), 96 echolucent (52.2%). Thirty-six patients had a contralateral I.C.A. stenosis, 11 had a contralateral I.C.A. occlusion. Twenty-four patients had a previously stented contralateral I.C.A.
Techniques of cerebral protection
- 149 lesions were treated using the continuous occlusion technique. Mean occlusion time (sec): 378 ± 180 (149-1479).
- 34 lesions were treated by the 2nd, staged technique. Mean dilation occlusion time (sec): 323 ± 149 (109-762), mean stent implantation occlusion time (sec): 299 ± 140 (125-717).
Mean occlusion time for all lesions (sec) was 422 ± 220 (125-1479).
Immediate Technical success
A technical success was achieved in 183/184 cases (99.5%).
There was one failure to cross the lesion with the Guardwire because of excessive tortuosity of the C.C.A. and I.C.A.. This procedure was successfully performed without cerebral protection.
In one patient, after completion of the procedure,
deflation of the occlusion balloon using the Microseal® adapter was impossible,
due to a kink at the Microseal® junction. This problem was managed by cutting
the hypotube section of the Guardwire distally to the Microseal® area,
using scissors and the balloon was then immediately deflated.
All lesions were treated with endoprostheses except three post-angioplasty restenoses. Were implanted 127 Palmaz stents (P204: 73, P154: 52, Corinthian: 2), 31 Wallstent, 28 nitinol self-expandable stents, 1 Jostent covered stent to treat the aneurysm. The Nitinol and Wallstent stents covered the bifurcation without jeopardizing the flow in the ECA. All stents were well deployed.
The mean stent diameter was 5.6 ± 1.4 mm at the proximal part, 5.2 ± 0.7 mm at the distal part. Mean stented lesion length was 22.8 ± 9.6 mm (15-57). The mean % residual stenosis was 3.5 ± 4.5 %.
Tolerance to Occlusion Balloon
The occlusion during protection balloon inflation was well tolerated in 176 cases (95.7%) whose 47 had a significant contralateral I.C.A. disease (stenosis or occlusion).
Two types of intolerance were observed:
A. Complete intolerance (2 patients, 1.1%) immediately after inflation of the protection balloon:
- One with total occlusion of the contralateral I.C.A. developed loss of consciousness and seizures. The patient totally recovered after rapid balloon deflation. CAS was successfully completed without cerebral protection.
- One with poor collateral circulation by the Willis circle developed also rapid loss of consciousness. But the procedure could be completed under protection. The patient totally recovered rapidly after deflation of the protection balloon.
B. Partial transient intolerance (6 patients, 3.3%): beginning approximately 2 minutes after flow interruption with transient symptoms such as agitation, brief loss of consciousness or transient neurological deficit. The procedure was completed under protection. All patients had rapid and complete recovery while the protection balloon was still inflated. Four of them had a brief hypotensive response to dilatation with bradycardia which could have promoted these intolerance.
Six patients developed a spasm of the I.C.A.
above the dilated area at the location of the protection balloon which rapidly
responded to vasodilators therapy.
Aspiration of the debris was performed in all patients.
The aspirated blood samples were collected
in filters (pores of 40 µm) and analyzed using optic and electron microscopic
techniques. Visible debris were extracted from all patients (mean diameter:
250 µm (56-2652), mean number per procedure: 74 (7-145). Different types
of particles were found: atheromatous plaques, cholesterol crystals, calcified
crystals, necrotic cores, fibrin, recent and old thrombi, platelets, macrophage
foam cells, lipoid masses and acellular material.
Carotid Duplex Scan
The Median Density Value of the atheromatous plaques having induced a carotid stenosis, evaluated by echoscanning in a subgroup of 20 patients, are shown in .
Low values of MDV were related to hypoechoic
plaques, high values to hyperechoic plaques. The hypoechoic plaques were related
to a greater number of particles with a relation between the MDV and the number
of particles of 0.72.
There was a good correlation between the MDV and the mean size of the debris (0.75), indicating that hyperechoic plaques produced larger debris.
Hypoechoic plaques were producing a great number of small particles, hyperechoic plaques less but larger debris.
No relationship between the degree of stenosis and the importance of embolism was found. The risk of embolization during CAS seems independent of the nature and severity of the plaque.
1. Four neurological complications occurred (2.2 %):
a) Three periprocedural complications (1.6 %):
- One amaurosis in a symptomatic patient having a tight ulcerated right ICA stenosis, after a Wallstent acute thrombosis during the procedure.
The thrombosis was seen on the angiogram after deflation of the protection balloon. This balloon was quickly re-inflated and abciximab injected (bolus of 0.25 mg/kg I.V. and 10 µg/mn continuous infusion for 12 hours thereafter). Thrombo-aspiration and flushing through the guide catheter were performed ten minutes later and the protection balloon finally deflated. The final angiogram showed no residual thrombus inside the stent. Nevertheless, the patient developed an amaurosis, which was probably the consequence of an embolism from the external carotid artery through a communication ECA-ophtalmic circulation. Indeed, a communication between the external carotid artery and the ophthalmic circulation was diagnosed after careful angiographic inspection.
- One TIA with transient hemiparesis after a procedure of CAS of a tight asymptomatic left I.C.A. stenosis in a patient who had a prolong occlusion time (19 minutes). No evidence of ischemia was detected at subsequent serial CT examinations.
- One TIA with brachial monoparesis in a symptomatic patient.
b) One intracerebral hemorrhage with hemiparesis on the third day after a CAS procedure under abciximab (same protocol as previously described), in a patient having a symptomatic subocclusion of the right I.C.A.. He partially recovered 2 months later.
2. Cardiac events (0.6%):
- No severe and/or prolonged bradycardia or hypotension were observed during and after the CAS procedure.
- No myocardial infarction occurred during the hospital period or in the 30 days after CAS.
- One symptomatic patient died from cardiac failure 3 weeks after the CAS procedure.
3. The overall 30-day incidence of stroke and death was 2.7 % (major stroke: 1.1 %, TIA: 1.1 %, death: 0.5 %) per patient.
4. No episode of cranial nerve palsy occurred.
The mean follow-up was 335 ± 165 days (30-940).
Three deaths occurred:
- One patient died from a major stroke located at the contralateral side of the previously treated I.C.A. at 6 months;
- Two other patients died from myocardial infarction.
No other minor or major stroke occurred.
One asymptomatic restenosis observed at 6 months was treated successfully by new angioplasty.
The event-free survival was 97% at 20 months ().
Recent randomized trials (2-4,28-29) have proved the efficacy of surgical endarterectomy for severe symptomatic and asymptomatic extracranial carotid artery stenosis and its superiority over medical treatment. However, the benefits of the procedure are critically dependent on the rate of perioperative complications (10,12,13).To consider CAS as an alternative to surgery, its complication rate should parallel that of endarterectomy.
CAS could be proposed in an increasing number of patients with carotid artery stenosis if an acceptable risk of perioperative stroke/death rate can be provided (16-23,31-34).
However, even with experienced interventionalists, the risk of embolic stroke, devastating complication, remains the main limitation of the procedure.
The frequency of debris migration and distal embolism has been demonstrated by ex-vivo human carotid stenting techniques (35) and confirmed by clinical studies (12,36).
The number of embolic particles generated by percutaneous techniques seems far exceed that of endarterectomy (33,35,36). Although their clinical significance has not been documented yet (36-37), it is known that their presence could not have any beneficial effect for the brain.
Furthermore, the minimum particle size capable of producing ischemic events has not been determined.
Various patient and plaque characteristics have been suggested as predictors of debris generation and embolic events (35,38) to define high-risk groups for CAS procedure. In our study, debris were extracted from all patients, even in lesions theoretically at low risk of cerebral embolism (restenosis, echogenic plaques, concentric lesions) suggesting that the risk of embolization is independent of the nature of the plaques. Additionally, stent deployment does not provide sufficient protection against embolic plaque debris migration. In all series of CAS, the embolic risk exists regardless the implantation technique and the stent characteristics. Manninen (38) compared endovascular stent placement with PTA of carotid arteries in cadavers in situ and found no difference with respect to distal embolization.
Vitek, in 1984, first reported (39) a case of successful innominate artery angioplasty where the risk of cerebral embolization was reduced by temporary occlusion of the origin of the right C.C.A. with a second balloon catheter. The last decade, as a testimony to suboptimal results and need for embolic risk elimination several protection techniques have been proposed during carotid angioplasty (40,41).
The PercuSurge Guardwire device was first tested in animals by OESTERLE (42) followed by clinical use (43) in 27 saphenous vein graft coronary angioplasties. It has been shown that the system was compatible with routine angioplasty procedures, capable of containing and retrieving atherosclerotic debris and might aid in the prevention of distal embolization.
The device has been proposed for cerebral protection during carotid angioplasty. One of its advantages is that it behaves similar to the steerable coronary guide wires, allowing to cross the stenosis easily and decreasing technical failures. We have experienced only one failure to cross a tight stenosis in a tortuous C.C.A. and I.C.A. Failure to cross the lesion could also occur in case of kinking or severe angulation of the carotid arteries. Additionally, the GuardWire provides efficient support to advance the dilation balloon and the stent. The deflation time of the occlusion balloon is fast and last approximately 15 seconds.
Limitation of the Technique
This study shows that protected CAS is a feasible and safe procedure with a very low 30-day neurological complications rate (2.2 %). These results are favorable when compared with series using brain unprotected techniques (16,18,21,37,44-45) and reach the historical surgical controls.
But cerebral protection can not prevent all plaque debris migration and embolic events that may occur at all steps of the procedure. The balloon protection device offers protection against embolism only after the lesion has been crossed by the wire, this maneuver as well the initial positioning of the guide catheter in the C.C.A. are also capable of releasing embolic material. Utilization of smaller tools, adaptation of coronary techniques may limit the risks and give a better outcome.
Tolerance of occlusion
Before the procedure, complete angiographic assessment of the 4 supra-aortic vessels is mandatory for determination of the collateral supply through the Circle of Willis, the vertebro-basilar and contralateral carotid flow. Patients with congenital absence or acquired disease of these structures may not tolerate flow occlusion. This problem is similar but not identical with surgical clamping during carotid endarterectomy since flow through the E.C.A. is unaffected with protection balloon inflation. The E.C.A. also provides, through collaterals, flow to both the anterior and posterior cerebral circulation useful when the I.C.A. is occluded, but potentially harmful in cases flushing is used to clean the treated area. In this study, occlusion of the I.C.A. was well tolerated in the majority of cases. We had 8 intolerances but only one complete intolerance (rapid development of symptoms immediately after flow interruption) in which cerebral protection was not used to complete the procedure.
More commonly a delayed intolerance of brief duration started while the procedure was well advanced, usually after stent deployment and before debris aspiration. In these cases, the procedure could be completed with aspiration and reestablishment of the cerebral flow, thus keeping the benefits of the protection.
After aspiration, potential remaining debris may be flushed towards the E.C.A. and lead to ischemic complications in cases of distal anastomosis between the E.C.A. and the I.C.A. or vertebro-basilar artery territory through the meningeal or occipital arteries. A diagnostic angiography prior to treatment is mandatory for diagnosis of these particularities which are more prevalent than expected. Nevertheless the absence of angiographic evidence of collateral circulation from E.C.A. to intracerebral vasculature pre-occlusion of the I.C.A., does not preclude evidence of this collateral route during I.C.A. occlusion, therefore, we think that the use of flushing must be ruled out and the debris removal restricted to aspiration. In our series, one neurological complication appeared after flushing. We stopped flushing after this occurrence.
Flushing vigorously at high pressure during the cleaning procedures may lead to reflux to the origin of the C.C.A. (more critical on the right side since the length of the C.C.A. is usually shorter) and/or to the right vertebral artery with the risk of neurological deficit in this territory.
We believe now that aspiration is sufficient to clean up the treated area.
The different protection devices
Various cerebral protection devices and techniques are proposed:
- Filters: Their most remarkable advantage is not to stop cerebral flow. Nevertheless the size of the pores (≥100µm today) unfortunately allow the flow of microparticles (47), which could lead to ischemic cerebral, particularly ocular complications and cognitive changes.
- Proximal balloon occlusion (Kachel technique) which consists in a balloon occlusion of the upper part of the C.C.A. during the procedure of CAS (40).
- Reversal flow technique recently proposed by Parodi (48,49) with occlusion of the upper part of the C.C.A. and of the E.C.A.. This technique allows crossing the lesion under protection avoiding brain embolism during this step. One hundred and two patients have been treated with this technique. No related-device neurological embolic event occurred (personal communication).
These devices have to be evaluated to define their respective indications.
Filters may have a more specific indication in patients with insufficient cerebral supply, hardly capable to tolerate a balloon occlusion. Nevertheless, in our series, we have seen that even with a contralateral carotid disease, the occlusion balloon was well tolerated in most of the cases. The reversal flow technique seems efficient and very promising (49).
Procedural considerations and late outcome
The importance of pretreatment with aspirin and ticlopidine or clopidogrel, as well as its duration, in preventing complications seem important but not proved. A randomized trial is needed to rigorously examine this issue. However, given the demonstrated importance of these agents in coronary stenting, such a trial seems unlikely to be undertaken.
Abciximab has been proposed (50) as an adjunct therapy. Its potential benefit and indications remain to be evaluated.
Clinical implications and futures studies
In the low-risk patients randomized into NASCET and ACAS, relief of obstruction has been shown to lower the risk of cerebrovascular events.
Whether relief of the obstruction in other patient groups with different baseline characteristics would have the same treatment advantage is not known with certainty, nor is the relative effectiveness of CAS and CE in preventing Ischemic Brain Infarction and death in the high-risk patients. In the series of Shawl et al (21), during the 19-month follow-up of patients, there were very few neurologic events, suggesting that the effectiveness of obstruction relief may well be reflected in long-term clinical benefit. The results of our CAS under cerebral protection series are similar and very promising.
For this reason, randomized controlled trials of CE versus CAS are now the next step in evaluating CAS. Until randomized trials are available, caution should be exercised in discarding CE in patient groups in which it has been proven effective.
One randomized trial - the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS), which examined the role of angioplasty versus CE - has been completed (51). This trial, although underpowered, suggested that balloon angioplasty without routine stenting has a similar safety profile to elective CE. These data suggest that routine stent implantation will further improve the percutaneous management of carotid artery disease.
A second trial that compares CE and CAS - the Carotid Revascularization Endarterectomy Trial (CREST), sponsored by the NIH - is planned (52). The final results of CREST will not be available for at least 5 to 6 years.
In the interim, there are sufficient published reports to support the use of CAS by experienced operators in patients known to be at high risk for CE (16-18,37,44-45,53). Such procedures require an experienced team of neurologists and interventionalists.
Patients at high risk for CE include patients with carotid artery lesions above the C2 or C3 cervical vertebrae or at the ostium of the common carotid artery and patients with cervical spine disease or fixation, previous radical neck dissection, fibromuscular dysplasia, previous cervical radiation, previous CE, and the presence of important comorbid conditions, including unstable angina, recent MI and severe congestive heart failure.
In addition, there will be continuing evolution of new stents, dilation and postdilation strategies, distal neuroprotection devices that will require evaluation.
This is a prospective non randomized monocentric study where CAS under cerebral protection was performed by highly experienced operators.
Whether similar results will be obtained by less experienced operators is not known.
This study represents early clinical experience with equipment designed for coronary and peripheral vascular interventions. Devices designed specifically for carotid artery intervention may improve outcome.
Randomized studies comparing the gold standard procedure of CE versus protected CAS, and CAS with and without cerebral protection are awaited, as well as randomized studies to evaluate and compare different neuroprotection devices (filters, protection balloon and others).
Carotid artery stenting has been demonstrated as feasible and safe, even in high-risk patients with a complication rate comparable to that of patients in the ACAS and NASCET trials.
But CAS without cerebral protection is associated with the risk of brain embolism. The addition of protection device may decrease this risk and their application to all cerebral angioplasty procedures might widen the indications and offer complication rates at least equal or even smaller than those obtained with CE.
Multicenter randomized studies (CAS versus CE) are awaited but is it ethical to set up now a study without cerebral protection?
In the interim, there are sufficient published reports to support the use of CAS by experienced operators in patients considered high-risk for surgery and higher risk patients could be treated because of the availability of protection.
The cost of these different techniques has to be evaluated.
Purpose: Recent studies suggest that carotid angioplasty and stenting (CAS) could be an alternative to carotid endarterectomy (CEA) for severe extracranial carotid artery stenosis. However, cerebral embolism is a serious complication of percutaneous techniques and their major limitation. Protection devices have recently been proposed to reduce the embolic risk. We examined the possible beneficial effect of a new device based on balloon occlusion of the distal internal carotid artery (I.C.A) during the procedure, followed by debris aspiration and in some instances saline-flushing of the I.C.A..
Methods: 190 CAS procedures were attempted under cerebral protection using the PercuSurge system in 173 patients (132 males, mean age 70.5 ± 9.2 years, 95 asymptomatic stenosis). Lesions were mainly atherosclerotic, restenotic (n = 18) and post-radiation (n = 9).
Results: Technical success: 99.6%. All lesions were stented except three post-angioplasty restenoses. The occlusion during protection balloon inflation was well tolerated in 182 patients (95.8%). Microscopic analysis of the aspirated blood showed different types of particles with a mean diameter of 250 µm (56-2652 µm) and a number of particles ranging between 7 and 145 per procedure. The 30-day stroke and death rate was 2.6% (3 periprocedural (<48h) neurological complications: 1 major stroke, 2 TIA; 1 intracerebral hemorrhage at day 3; 1 death 3 weeks later from unrelated cause).
Conclusions: This study yields favorable results in comparison with standard CAS series concerning peri-procedural embolic events. Protection devices may play an important role in future carotid interventions and expand the applicability of the procedure. Randomized studies (CEA versus CAS under or without cerebral protection) are awaited.
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2nd Virtual Congress of Cardiology
Dr. Florencio Garófalo
Dr. Raúl Bretal
Dr. Armando Pacher
Technical Committee - CETIFAC
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