Complications of carotid angioplasty and stenting

Evaluation of the self-expanding effect of carotid stents in the early postoperative period

PURPOSE

To evaluate the expansion effect of self-expandable stents during the first week after carotid artery stenting (CAS) procedure and to examine the variation of the effect according to the carotid plaque type.

METHODS

Seventy stenotic carotid arteries of 69 patients were stented by using self-expanding Wallstents with diameters of 7 and 9 mm, after detection of stenosis and plaque type by Doppler ultrasonography. Post-stent aggressive ballooning was avoided and residual stenosis rates were measured with digital subtraction angiography. After the stenting procedure, the caudal, narrowest, and cranial diameters of stents were measured with ultrasonography at 30 min, first day and first week. Stent diameter increase and change according to plaque type were evaluated. Two-way repeated measure ANOVA test was used for statistical analysis.

RESULTS

A significant increase was observed in the mean stent diameter in the three stent regions (caudal, narrow, and cranial) from the 30th minute to the first and seventh days (p < 0.001). The most prominent stent expansion occurred in the cranial and narrow segments within the first day. In the narrow stent region; Stent diameter increase between 30th minute-first day, 30th minute-first week, and first day-first week were all significant (p < 0.001). At 30 min, first day, and first week, no significant difference was detected between plaque type and stent expansion in caudal, narrow, and cranial regions (p = 0.286).

CONCLUSION

We think that keeping the lumen patency limited to 30% residual stenosis after CAS procedure by applying minimal post-stenting balloon dilatation and leaving the remaining lumen expansion to the self-expanding feature of the Wallstent might be a sensible approach in order to avoid embolic events and excessive carotid sinus reactions (CSR).

Delayed Iatrogenic Direct Carotid Cavernous Fistula Following Flow Diversion for Aneurysm With Spontaneous Healing: A Case Report

An abnormal connection between the carotid artery and cavernous sinus is referred to as a carotid cavernous fistula (CCF). A direct CCF results when the connection occurs between the intracranial internal carotid artery (ICA) and the cavernous sinus. These events are typically the result of a head injury, but can also be iatrogenic, resulting from various intracranial procedures. Direct CCF occurrences rarely heal spontaneously due to the high flow rate across the fistula. In this report, we present an uncommon case involving a delayed iatrogenic direct CCF, which developed following the placement of a pipeline flow-diverting stent that was used to treat a cerebral aneurysm. Interestingly, this unusual iatrogenic direct CCF subsequently spontaneously resolved within a few months. To our knowledge, this is the only case of a delayed CCF occurring with the use of a flow-diverting sent, which then resolved on its own. This report recounts our experience with the case.

[Hybrid interventions for tandem occlusions in acute phase of ischemic stroke]

OBJECTIVE

To evaluate the effectiveness of hybrid interventions, i.e. endovascular mechanical thrombectomy from intracranial arteries combined with open thrombectomy or carotid endarterectomy from extracranial internal carotid artery.

MATERIAL AND METHODS

We analyzed 16 patients who underwent mechanical thrombectomy/thrombaspiration combined with open surgery between January 2014 and March 2021. All patients had occlusion of extracranial and intracranial segments internal carotid artery or initial segments of the middle cerebral artery. Baseline data, diagnostic algorithm, timing and results of treatment were analyzed. Study endpoints were technical success of revascularization, clinically significant hemorrhagic transformation, NIHSS and modified Rankin score of neurological impairment, as well as outcome of disease within 90 days.

RESULTS

We restored patency of ICA and intracranial arteries in 13 out of 16 patients. In 9 patients, we obtained a positive effect with significant regression of neurological symptoms (mRS <2). In 3 patients, severe neurological deficit persisted throughout the entire follow-up period. Four patients died. Thus, effectiveness of technique was 56.2% (t=3), mortality rate was 25% (t=2.3). There was a relationship between the timing of interventions and outcomes of disease. Indeed, all dead and most of disabled patients underwent surgery later than 6 hours from the onset of disease.

CONCLUSION

Hybrid interventions for tandem occlusions of carotid arteries can significantly increase efficiency and accelerate recanalization of great extracranial vessels in patients with tandem lesions in acute phase of ischemic stroke. Moreover, hybrid interventions significantly reduce the cost of reperfusion procedure. In case of severe atherosclerotic stenosis, simultaneous open endarterectomy from common and internal carotid arteries has a significant advantage over stenting due to no need for antithrombotic therapy.

Carotid Cavernous Fistulae Occurring After the Use of the Fogarty Catheter in Carotid Surgery

The Fogarty catheter represents a major advancement for the effective removal of distal thrombi during vascular surgery, including carotid endarterectomy (CEA). One complication related to its use is injury to the cavernous carotid artery with development of a carotid cavernous fistula (CCF). Including a recent case at our institution, 21 patients with a Fogarty-related CCF have been reported since 1967. We performed a detailed review of all Fogarty-related CCFs during the treatment of carotid occlusive disease. We suggest a management algorithm for post-CEA acute carotid occlusion.

Delayed caroticocavernous fistula after stent-assisted coil embolization of intracavernous carotid aneurysm: should we manage conservatively?

Constructive endovascular techniques remain the mainstay for the treatment of cavernous carotid aneurysms due to their efficacy. However, they do harbor risks of complications, such as thromboembolic events, arterial injuries, and vessel occlusions. A 58-year-old lady presented with delayed caroticocavernous fistula (CCF) 1 month after stent-assisted coil embolization of a cavernous carotid aneurysm (CCA). Following this, her caroticocavernous fistula resolved spontaneously with no further intervention. Our case demonstrates a unique presentation of a CCF as a delayed complication of stent-assisted coil embolization of CCA and the spontaneous resolution of the CCF. Symptomatic CCFs are commonly treated as an emergency in many institutions and the question arises as to whether we should adopt a conservative policy in the light of this case report.

Transarterial coil embolization of a carotid-cavernous fistula which occurred during stent angioplasty

Intracranial endovascular procedures are less invasive and relatively safe; however, these procedures do carry a risk of complications, such as thromboembolization, arterial injury, and vessel occlusion. We present a case of carotid-cavernous fistula development secondary to injury of the cavernous segment of the internal carotid artery (ICA) during stent angioplasty and its treatment by transarterial coil embolization. Probable causes of this complication and its treatment method are discussed. To the best of our knowledge, this is the first report of such a case.

[Anesthesia in interventional neuroradiology]

Interventional neuroradiology procedures have become increasingly complex, requiring planning and coordination. Key roles are played by the anesthesiologist and the radiologist, as well as by technicians and nurses. This review aims to analyze the anesthesiologist's part in managing these procedures, from the start of the intervention through the immediate postoperative period. First concerns are to assure patient safety during transfer, maintain the airway, keep the patient immobile and hemodynamically stable, and manage anticoagulant and antiplatelet treatments. Rapid awakening must also be assured so that the patient's neurologic status can be assessed in situ. The anesthesiologist should treat any neurologic complications that develop and that might lead to emergency situations during the procedures.

Exclusion of Atherosclerotic Plaque from the Circulation Using Stent-Grafts: Alternative to Carotid Stenting with a Protection Device?

PURPOSE

To retrospectively assess the feasibility, safety, and clinical mid-term outcome of patients undergoing carotid artery stenting with stent-grafts.

METHODS

Over a 4 year period stent-grafts were used in the endovascular treatment of symptomatic internal carotid artery stenosis in 12 patients (2 women, 10 men, aged 47-83 (mean 64) years). Protection devices were not used. Possible microembolic complications were evaluated by magnetic resonance imaging (MRI) examinations of the brain before and the day after the procedure in all patients. Mean follow-up was 22 months (range 1-42 months), by Doppler ultrasonography and conventional angiography as well as clinical examination.

RESULTS

The technical success rate was 100%. A total of 13 coronary stent-grafts were used. The mean stenosis rate (in terms of diameter) was 85% and the mean length of stent-grafts used was 20.9 mm. The mean diameter to which the stent-grafts were dilated was 4.66 mm. In-hospital complications occurred in 1 patient who suffered a minor femoral access hematoma that did not require transfusion or surgical decompression. Post-stenting diffusion-weighted MRI revealed several ipsilateral silent microemboli in only 1 case, which was completely asymptomatic. Two patients had a major stroke after 2 years of follow-up. Restenosis was found in 2 patients who underwent successful balloon dilatation followed by placement of a self-expandable bare stent within the stent-grafts.

CONCLUSIONS

Stent-grafts may prevent microembolic complications during stenting of atherosclerotic carotid lesions in selected cases, offering immediate exclusion of the atherosclerotic lesion from the circulation by pressing the plaque against the vessel wall. Comparative, randomized studies in larger series of patients are needed with carotid-dedicated stent-graft designs.

Protected stent-assisted angioplasty in radiation-induced carotid artery stenosis

OBJECTIVE

The surgical treatment of radiation-induced carotid stenosis is challenging and presents a high rate of complications. This has led several investigators to propose stent-assisted angioplasty as the treatment of choice for this condition. The aim of this study is to evaluate the potential risks of intra-procedural embolic stroke in this setting using cerebral protection devices.

METHODS

We describe our recent experience in the endovascular treatment by means of stent-assisted angioplasty with the aid of a filter cerebral protection device of eight patients presenting with radiation-induced carotid stenosis.

RESULTS

Procedural success, defined as residual stenosis of less than 30% was obtained in all cases. The mean percentage stenosis was reduced from mean 80+/-6.3% (range 70-90%) to 13+/-4% (range 10-20%). Predilation was performed in five cases, post-dilation in all the cases. Mild-to-moderate bradycardia while inflating the balloon was present in three cases and was severe in one case. No patient sustained myocardial infarction, stroke or TIA during the procedure or hospital stay. During a mean clinical follow-up of 16+/-7.3 months (range 5-25) there were no neurological events. On sonographic follow-up, no patient presented in-stent de novo stenosis.

DISCUSSION

Carotid angioplasty with cerebral protection can be performed safely in radiation-induced carotid stenosis with a high technical success rate. With the recent innovations and improvements in angioplasty technique, its indications and results will have to be redefined. Given the complexity and complications of surgical approaches for this condition, and the encouraging results obtained with endovascular techniques, carotid angioplasty emerges as the preferred treatment option.

An in vitro analysis of a carotid artery stent with a protective porous membrane

PURPOSE

To prove the effectiveness of a new stent concept with integrated protection (MembraX [MX]) by comparing it with five cerebral protection devices designed for carotid angioplasty in an in vitro model.

MATERIALS AND METHODS

Two simulation series of embolization from carotid angioplasty have been performed. In the first series, polyvinyl-alcohol particles (150-250 microm [small], 355-500 microm [medium], 710-1000 microm [large]; 5 mg each) were injected into a silicone flow model simulating the aortic arch with a carotid bifurcation. The particles were injected proximally to the partially deployed MX stent or one of the following protection devices: Angioguard (AG), FilterWire EX (EX), Trap, Neuroshield (NS), or GuardWire Plus (GW). Particles evading the protection device were caught in a filter at the end of the flow model and weighed. In the second series, human plaque material (8-12 particles; total weight 6.09 +/- 0.01 mg; 500-1500 microm) was injected into the model with the respective devices. MX was compared with the AG, EX, Trap, and NS devices.

RESULTS

MX had the most effective overall filtration performance for polyvinyl alcohol particles in the effluent of the internal carotid artery (ICA; 0.43 mg, 2.9%), compared with NS (0.53 mg, 3.5%), GW (1.10 mg, 7.0%), EX and AG (1.18 and 1.21 mg, respectively; 7.8% and 8.0%), and Trap (1.24 mg, 8.2%). MX performed best for the small particles (2.0% passed particles into ICA; P < .05 compared with all). Human plaque material was retained best in the in vitro model by MX (0.0%), followed by NS (0.8%), EX (1.3%), Trap (2.6%), and AG (4.4%).

CONCLUSIONS

In vitro, none of the tested devices had the ability to prevent embolization completely. Comparing current designs, the MX device captured the highest percentage of the three different particle groups. Tested with human plaque emboli, MX performed effectively in filtering the particles in the ICA.

Comparison of various cerebral protection devices used for carotid artery stent placement: an in vitro experiment

PURPOSE

To compare the effectiveness of five basic cerebral protection devices designed for carotid angioplasty in an in-vitro bench-top model.

MATERIALS AND METHODS

Simulation of embolization from carotid angioplasty (n = 180) was performed with polyvinyl alcohol (PVA) particles (Contour; 150-1,000- micro m) in an open flow model simulating the aortic arch with a carotid bifurcation made from elastic silicone tubes. Particles (150-250 micro m [small], 355-500 micro m [medium], 710-1,000 micro m [large]; 5 mg each) were injected separately into the internal carotid artery (ICA) proximal to the placed protection device. Five devices were tested: the Angioguard (AG), Filter Wire EX (EX(A), EX(B)), Trap, Neuroshield (NS), and GuardWire Plus (GW). Particles getting past the protection device or flowing into the external carotid artery (ECA) were caught in a filter at the end of both arteries and their weight was determined.

RESULTS

For small, medium, and large particles, the lowest weight of emboli in the effluent of the ICA was obtained with the NS (0.28 mg, 0.18 mg, and 0.07 mg, respectively; P <.001 compared to all other devices except the GW for small particles only). The GW had the highest embolization rate into the ECA for all particle sizes. When combining the particle weights for the different protection devices, the NS showed the lowest weight of emboli into the ICA filter (0.53 mg/3.5%; P <.001 compared to all [>1.1 mg/7.0%]). The GW revealed the highest weight of emboli into the ECA (1.2 mg/7.6%; P <.001 compared to all [<0.59 mg/0.09%]). Effectiveness of the EX(B) device was enhanced when circumferentially deployed under direct view (EX(B), 0.39 mg/2.58%; EX(A), 1.18 mg/7.81%; P <.001).

CONCLUSIONS

In vitro, none of the tested devices or modifications has the ability to prevent embolization completely. An occlusion balloon leads to increased embolization into the ECA. The effectiveness of the EX might be enhanced with design improvements. During this evaluation, the NS was most effective for preventing PVA particle embolization of the three different particle groups within this in-vitro model.

Carotid stent angioplasty: the role of cerebral protection devices

Carotid endarterectomy has been validated with results of several randomized controlled trials in which its effectiveness has been demonstrated over that of the best nonsurgical therapy. However, in the past several years, carotid angioplasty with stent placement has emerged as a potential safe and effective alternative to carotid endarterectomy. In this article we examine the current status of carotid angioplasty with the recent introduction of innovative cerebral protection devices and improved endovascular devices. We present a brief description of the current randomized trials evaluating carotid endarterectomy compared to carotid angioplasty as well as our combined experience in 262 patients.

In vitro comparison of four cerebral protection filters for preventing human plaque embolization during carotid interventions

PURPOSE

To evaluate in an in vitro bench-top model the efficacy of 4 filtration devices designed for cerebral protection during carotid angioplasty.

METHODS

Embolization during carotid angioplasty was simulated with human plaque material (8 to 12 particles weighing 6.02 +/- 0.10 mg) in an open flow model with the aortic arch and carotid bifurcation made from elastic silicone tubes and saline used as the fluid medium. The 500 to 1500-microm particles were injected into the internal carotid artery (ICA) in front of the test protection device, which was deployed 5 cm distal to the bifurcation. Particles getting past the protection device or flowing into the external carotid artery (ECA) were caught in 100-microm filters and weighed. Ten trials were made on each of 4 devices: Angioguard, FilterWire EX, TRAP, and NeuroShield. All were deployed according to the manufacturers' directions except the FilterWire, which was manually repositioned in all tests to eliminate a gap between the filter and the tube wall.

RESULTS

The lowest weight of missed particles in the effluent was obtained with the NeuroShield (0.05 +/- 0.04 mg, 0.8% of injected particle weight) and FilterWire (0.08 +/- 0.05 mg, 1.3%; p=0.254 compared to NeuroShield, p=0.006 versus TRAP). The weight of particles missed by the TRAP device (0.16 +/- 0.06 mg, 2.6%; p<0.001 versus NeuroShield and Angioguard, p<0.05 compared to FilterWire) was higher, and the largest amount of missed particles was observed with the Angioguard filter (0.27 +/- 0.06 mg, 4.4%; p<0.001 compared to all). NeuroShield and FilterWire were significantly different (p<0.001) compared to Angioguard and TRAP in a pairwise analysis. No embolization into the ECA occurred.

CONCLUSIONS

In vitro, none of the tested devices had the ability to completely prevent embolization into the ICA. Comparing current designs, the NeuroShield filter and the FilterWire EX captured the highest percentage of human particles in this in vitro model, probably due to their larger filter volume.

Comparison and modification of two cerebral protection devices used for carotid angioplasty: in vitro experiment

The effectiveness of two basic cerebral protection devices designed for carotid angioplasty with and without additional aspiration techniques was compared in an in vitro model. During carotid angioplasty, embolization was simulated by injecting polyvinyl alcohol particles of different sizes into the model system. None of the tested devices, all of which were positioned in the internal carotid artery, was able to completely prevent embolization. In the internal carotid artery, the rate of particle capture did not vary among protection devices. However, embolization into the external carotid artery was more frequent with use of the GuideWire, as compared with that with use of the Angioguard.

Role of the distal balloon protection technique in the prevention of cerebral embolic events during carotid stent placement

BACKGROUND AND PURPOSE

We sought to quantitatively and qualitatively evaluate the release of atheromatous plaque debris induced by carotid stenting procedures.

METHODS

Eight patients with severe carotid atheromatous stenoses were treated by stent implantation under distal balloon protection. Blood samplings were obtained after stent deployment in the blood pooled below the inflated protection balloon. The samples were centrifuged and evaluated for plaque debris with the use of light microscopy. The debris release was quantitatively estimated by dividing the total volume of debris obtained by the mean debris size. Five patients without endovascular procedure were used as a control group.

RESULTS

The 2 main debris types found were nonrefringent cholesterol crystals (4 to 389 microm; 115 to 8697 in number) and lipoid masses (7 to 600 microm; 341 to 34 000 in number). There was a statistically significant difference compared with the samples obtained in the control group (P:=0.017).

CONCLUSIONS

Blood samples collected during stent implantation procedures contain a large quantity of atheromatous plaque debris. This emphasizes the role of distal protection techniques in avoiding migration of this plaque material into the cerebral circulation.

Carotid artery stent placement for atherosclerotic disease: rationale, technique, and current status

Carotid arterial endarterectomy is considered to be the standard for the treatment of atherosclerotic carotid arterial occlusive disease. This has been validated with results of several randomized controlled trials in which its effectiveness has been demonstrated over that of the best nonsurgical therapy. In the past several years, however, carotid angioplasty with stent placement has emerged as a potential alternative to carotid endarterectomy. This article represents a critical examination of the rationale for carotid revascularization; the history of endovascular techniques for the treatment of carotid atherosclerosis, beginning with balloon angioplasty and evolving to the use of stents; and the evidence supporting the effectiveness of the endovascular approach. A brief description of the current technical aspects of carotid artery stent placement is presented. The future status of the endovascular approach will be determined with randomized trials in which carotid artery stent placement is directly compared with endarterectomy, as well as by the potential for further innovation and improvement in endovascular devices, technique, and safety.