Impact of routine completion angiography on outcome after carotid endarterectomy

Objective

The objective of this study was to analyze the impact of completion digital subtraction angiography (cDSA) after carotid endarterectomy (CEA) on technical and early clinical results.

The haemodynamic value of external carotid artery collateral blood supply in carotid artery disease

In the presence of severe obstruction of the internal carotid artery (ICA) blood supply to the ipsilateral hemisphere may be provided by collaterals. Whereas the circle of Willis in many cases makes a substantial contribution to cerebral perfusion, the value of collateral blood supply originating from the external carotid artery (ECA) is not clear. In thirty-five patients undergoing carotid endarterectomy (24 with proven external carotid artery collaterals) intra-arterial blood pressures were measured across the ICA stenosis, prior to endarterectomy. In order to evaluate the haemodynamic value of ECA collaterals, the distal ICA pressure was measured with and without the ECA clamped. In addition, volume blood flow in the common carotid artery was measured with and without the ECA clamped, before and after endarterectomy. No significant change in distal ICA pressure was observed when the ECA was clamped, whether or not external carotid artery collaterals had been demonstrated preoperatively. The greatest reduction in mean distal ICA pressure observed upon ECA clamping was 8 mmHg. However, this only occurred in three of 11 patients with a severe pressure reduction across the stenosis. ICA blood flow increased significantly following endarterectomy whereas ECA flow was reduced. This study indicates that ECA collaterals in most cases do not contribute substantially to cerebral perfusion. Endarterectomy of the ECA, in order to improve cerebral circulation, seems justified only in selected cases, where the distal ICA pressure has been shown to be severely reduced.     

Volume of subclinical embolic infarct correlates to long-term cognitive changes after carotid revascularization

Objective

Carotid intervention is safe and effective in stroke prevention in appropriately selected patients. Despite minimal neurologic complications, procedure-related subclinical microemboli are common and their cognitive effects are largely unknown. In this prospective longitudinal study, we sought to determine long-term cognitive effects of embolic infarcts.

The contribution of the external carotid artery to cerebral perfusion in carotid disease

PURPOSE: In the presence of carotid occlusion, the external carotid artery (ECA) becomes an important source of cerebral blood flow, especially if the circle of Willis is incomplete. The contribution of the ECA to hemispheric blood flow in patients with severe ipsilateral carotid stenosis has never been previously investigated. METHODS: One hundred eight patients were monitored during sequential cross-clamping of the external (ECA) and then ipsilateral internal carotid artery (ICA) during carotid endarterectomy using transcranial Doppler sonography (TCD) (Neuroguard CDS, Los Angeles, Calif), to measure middle cerebral artery blood flow velocity, and near-infrared spectroscopy, to measure regional cerebral oxygen saturation (CsO(2)) (Invos 3100A; Somanetics, Troy, Mich). RESULTS: On the ipsilateral ECA cross-clamp, the median fall in CsO(2) was 3% (interquartile range, 1%-4%; P <.0001). On addition of the ICA cross-clamp there was a further fall of 3% and a total fall of 6% (3%-9%; P <.0001). The median percentage fall in middle cerebral artery blood flow velocity on ECA clamping was 12% (4%-24%; P <.0001); on ICA clamping it was 48% (25%-74%; P <.0001). Falls in TCD on ECA clamping were greater with increasing severity of ipsilateral ICA stenosis. The correlation between CsO(2) and TCD on external clamping, although less strong than that on internal clamping, was statistically significant r = 0.32; P =.01; Spearman rank correlation). CONCLUSIONS: The falls in TCD and CsO(2) were of a similar order of magnitude and must therefore reflect a fall in cerebral perfusion. The ipsilateral ECA contributes significantly to intracranial blood flow and oxygen saturation in severe carotid stenosis.     

Cerebral protection during retrograde carotid artery stenting for proximal carotid artery stenosis: technical note

Carotid artery stenting for carotid bifurcation stenosis usually uses the transfemoral approach. However, in patients with proximal common carotid artery (CCA) stenosis, the guiding catheter is difficult to introduce into the narrow origin of the CCA without risking cerebral embolization before activation of the protection device. A technique of cerebral protection by internal carotid artery (ICA) clamping with or without simultaneous external carotid artery (ECA) clamping was used to treat patients with proximal CCA stenosis by the retrograde direct carotid approach. The carotid bifurcation was surgically exposed and retrograde catheterization was performed to approach the stenosis. The ICA was clamped during angioplasty and stenting to avoid cerebral embolization. The ECA was clamped simultaneously if any extracranial-intracranial anastomosis was present. None of five patients treated with this technique experienced ischemic complications attributable to this technique.     

Hemodynamic conditions at the carotid bifurcation during protective common carotid occlusion.

OBJECTIVES: Carotid angioplasty and stenting procedures are associated with an obligatory release of particulate debris into the distal cerebral circulation. Although most of the emboli are small and do not result in symptomatic neurologic deficits, some may be large enough to cause stroke. For this reason, a variety of filters and balloon occlusion devices have been employed as adjuvants to decrease the risk of distal embolization during carotid stenting. Some of these devices rely on the arrest of antegrade blood flow with the use of inflow arrest. The present study was undertaken to investigate the hemodynamic conditions that exist at the carotid bifurcation during common carotid artery (CCA) occlusion. METHODS: Internal carotid artery (ICA) and external carotid artery (ECA) stump pressures were measured in 29 patients undergoing carotid endarterectomy. Duplex ultrasound scanning was used to measure the direction and velocity of blood flow in the ICA and ECA with the CCA cross-clamped but the ICA and ECA open, a clinical scenario analogous to CCA balloon occlusion at the time of carotid angioplasty and stenting. The direction and magnitude of ICA and ECA flow were compared with the stump pressures to determine whether a correlation existed between these variables. RESULTS: The mean stump pressure in the ICA and ECA averaged 56 +/- 16 and 53 +/- 12 mm Hg, respectively. The ICA systolic stump pressure was lower than the ECA systolic stump pressure in six patients (21%), and all of these patients had persistent antegrade systolic duplex blood flow by duplex interrogation during CCA occlusion. The ICA systolic stump pressure exceeded the ECA systolic stump pressure in 19 patients (66%), and all of these patients had retrograde ICA flow during systole. Diastolic flow was also well correlated with the magnitude of the ICA/ECA stump pressure differential, with antegrade diastolic ICA blood flow in all nine patients with an ICA diastolic stump pressure less than the ECA diastolic stump pressure. None of the 10 patients with ICA diastolic stump pressure greater than ICA diastolic stump pressure maintained antegrade ICA diastolic flow, but four of these patients had flow to zero in diastole. Overall, 13 of 29 patients (45%) could be surmised to be at risk for distal embolization to the brain based on the persistence of some element of either systolic or diastolic antegrade ICA flow during common carotid occlusion. CONCLUSIONS: Common carotid occlusion alone appears insufficient to protect against distal embolization during manipulations of the carotid bifurcation. Persistent systolic or diastolic antegrade blood flow occurs in a high proportion of patients, lending credence to the use of additional protective strategies to ameliorate the risk of embolic complications.     

The role of external carotid revascularization in the treatment of ocular ischemia

During the past 13 years, 16 patients with visual disturbances, ipsilateral internal carotid artery (ICA) occlusion, and external carotid artery (ECA) stenosis have had ECA reconstruction. Indications for operation included amaurosis fugax (AF) in five patients, AF and transient ischemic attacks in four patients, ischemic optic neuropathy in two patients, retinal artery occlusion in one patient, and blurry vision and scotomata in four patients. In 12 cases (75%), there were hemodynamically significant contralateral ICA lesions, including four contralateral ICA occlusions. EC endarterectomies were performed in 15 patients, whereas one patient was treated with a bypass graft. One transient neurologic event occurred in the perioperative period (6%). There were no deaths nor permanent neurologic deficits. Patients were followed up for periods of 1 to 60 months (mean 18.4 months). Two patients had AF postoperatively; in one instance, AF was associated with ECA thrombosis 53 months after operation. One patient had a transient ischemic attack when the ECA thrombosed 24 months after operation. This study demonstrates that visual symptoms can occur despite ipsilateral ICA occlusion. ECA revascularization is effective and can be performed with acceptable morbidity and mortality.     

Computational analysis of effects of external carotid artery flow and occlusion on adverse carotid bifurcation hemodynamics

OBJECTIVE: This is a computational analysis of the effects of external carotid artery (ECA) flow, waveform, and occlusion geometry on two hemodynamic wall parameters associated with intimal hyperplasia and atherosclerosis.Study design Transient three-dimensional fluid mechanics analysis was applied to a standard carotid artery bifurcation. Mean internal carotid artery (ICA) flow was maintained at 236 mL/min with a normal waveform. ECA flow was increased from zero to 151 mL/min (64% of ICA flow) with both a normal biphasic waveform and a damped waveform. Geometry of five ECA occlusions was studied: distal, proximal stump, smooth, smooth without carotid sinus, and optimal reconstruction.Primary outcome measures Two time-averaged and area-averaged hemodynamic wall parameters were computed from the velocity and wall shear stress (WSS) solutions, ie, wall shear stress angle gradient (WSSAG) and oscillatory shear index (OSI). Both local and area-averaged hemodynamic wall parameters were computed for the distal common carotid artery (CCA) and the proximal ICA. RESULTS: When ECA flow with a normal waveform is increased from zero to 151 mL/min, area-averaged WSS values increase in the CCA, from 3.0 to 4.4 dynes/cm(2) (46%), and in the ICA, from 16.5 to 17.1 dynes/cm(2) (4%); minimum local WSS values in the carotid sinus remain less than 1 dyne/cm(2); maximum local values of WSSAG and OSI are observed in the carotid sinus and increase from 3.5 to 9.1 radian/cm (160%) and 0.23 to 0.46 (100%), respectively; CCA plus ICA area-averaged WSSAG increases by 52%, and OSI increases by 144%; and damping of the ECA waveform has little effect on local or area-averaged WSSAG but reduces OSI to 68%. When the ECA is occluded, the minimum local WSS in the carotid sinus is less than 1 dyne/cm(2). However, if the carotid sinus is removed or the CCA-ICA geometry hemodynamically optimized, the minimum WSS is approximately 4 dynes/cm(2). Similarly, eliminating the carotid sinus markedly reduces local maximum WSSAG, from 3.0-3.5 radian/cm to 0.3 radian/cm, and reduces local maximum OSI from 0.22-0.49 to 0.04. Area-averaged WSSAG and OSI over the CCA and ICA are reduced by approximately 50% with elimination of the carotid sinus. CONCLUSIONS: The degree of adverse carotid bifurcation hemodynamics as measured with WSSAG and OSI is directly proportional to ECA flow. The marked difference in normal ICA and ECA flow waveforms does not contribute to adverse wall hemodynamics. Location of an ECA occlusion (distal, proximal, stump, smooth) does not affect adverse carotid hemodynamics; however, marked improvement is obtained with elimination of the carotid sinus.     

Direct and primary carotid endarterectomy for common carotid artery occlusion. Report of 2 cases

BACKGROUND: Cerebral ischemia associated with chronic CCA occlusion is a rare condition and raises strategic dilemma when the revascularization is needed. METHODS: Two patients with CCA occlusion presented with ischemic symptom associated with the affected side. Both patients underwent vascular reconstruction by direct carotid endarterectomy to achieve primary restoration of CCA to ICA flow. RESULTS: Successful reopening of the vessels was obtained in both patients without the evidence of postsurgical ischemic event. Follow-up MRA was obtained at later than 6 months after surgery, which demonstrated patent CCA-ICA in both patients. CONCLUSIONS: Direct carotid endarterectomy of the occluded CCA can be safely performed if the preoperative angiography suggest still patent vessels distal to carotid bifurcation and the substantial "back flow" is obtained from ICA during arteriotomy.     

Correlation of postoperative and two-year follow-up angiography with neurological function in 99 carotid endarterectomies in 86 consecutive patients.

Eighty-six consecutive patients in 1982 underwent 99 endarterectomies and routine postoperative digital subtraction angiography. Ten vessels were closed primarily and 89 with a patch graft. Minor morbidity was 2%, major morbidity 0%, and mortality 1%, but these varied according to the patient's preoperative medical and neurological function and angiographic findings. Postoperative patency for the common carotid artery (CCA) and internal carotid artery (ICA) was 100% and for the external carotid artery (ECA) 97%. Seventy-nine vessels were evaluated by a DSA 2 years after surgery. There was one asymptomatic occlusion in follow-up and one symptomatic re-stenosis in a patient with a proven heparin induced hypercoagulability state. The three postoperative ECA occlusions were associated with a lethal postoperative stroke, the only ICA occlusion in follow-up, and a 50% stenosis of the CCA in follow-up at the site of ECA occlusion. Vein patch grafting protected the ICA but not the CCA from recurrent stenosis. The carotid slim sign on preoperative angiograms is judged to indicate a patient at high risk of stroke morbidity.     

Noninvasive analysis of conjunctival microcirculation during carotid artery surgery reveals microvascular evidence of collateral compensation and stenosis-dependent adaptation

OBJECTIVE: Hemodynamically relevant internal carotid artery (ICA) stenosis is a major cause of ischemic stroke. Despite its long-term benefit, carotid endarterectomy may also be associated with severe neurologic deficits. Intraoperative and early recognition of ischemia in the region of the ICA may reduce this risk. To date, direct imaging and quantitative analysis of microvascular structures and function in the human ICA region have not been possible. We purposed to visualize and quantify ischemia/reperfusion-induced microcirculatory changes in the terminal vascular bed of the ICA in patients undergoing unilateral ICA endarterectomy. METHODS: Sequential analysis of the ipsilateral and contralateral conjunctival microcirculation was performed with orthogonal polarized spectral imaging in 33 patients undergoing unilateral ICA endarterectomy because of moderate or severe ICA stenosis (North American Symptomatic Carotid Endarterectomy Trial score, 75% +/- 13%), before clamping the ICA (baseline), during clamping of the external carotid artery and ICA, during reperfusion of the ICA (intraluminal shunt), during the second clamping of the ICA (shunt removal), after declamping (reperfusion) of the external carotid artery and ICA, and 15 to 20 minutes after the second ICA reperfusion. RESULTS: During ICA clamping for shunt placement, ipsilateral and contralateral conjunctival capillary perfusion was significantly decreased, but it was completely restored after reperfusion with carotid shunting. Reclamping of the ICA for shunt removal caused microvascular dysfunction, which was significantly less pronounced than that observed during the first clamping. The individual degree of ICA stenosis was inversely correlated with the ipsilateral and contralateral decrease in conjunctival functional capillary density during the first ICA clamping. CONCLUSIONS: These results suggest adaptive mechanisms of capillary perfusion with increasing stenosis and development of collateral compensatory circulation in the vascular region of the human ICA. Conjunctival orthogonal polarized spectral imaging during unilateral ICA reconstruction enables continuous noninvasive analysis of bilateral conjunctival microcirculation in the terminal region of the ICA and enables monitoring for efficient carotid shunt perfusion during and after endarterectomy.     

External carotid endarterectomy: indications, technique, and late results

In the past 14 years, 22 patients (25 operated sides), with occlusion of the internal carotid artery (ICA), underwent ipsilateral external carotid artery (ECA) endarterectomy at our institution. Operative indications were amaurosis fugax in 13 sides and nonlateralizing transient ischemic attacks in the remaining 12. There were no operative deaths. One patient suffered a minor stroke after operation. Follow-up ranged from 6 to 110 months (median 36 months). In 16 cases, simple endarterectomy with or without vein patch closure was performed (type I). In two cases the ostium of the ICA was occluded with interrupted sutures after endarterectomy (type II). In the remaining seven cases the ICA was transposed as a patch over the endarterectomized ECA after endarterectomy (type III). All but six patients (six sides) underwent duplex scanning or angiography during follow-up. Four of nine patients with previous nonlateralizing symptoms had persistent symptoms after operation, whereas none of those with previous amaurosis fugax did. Recurrent occlusive disease was more common in type I reconstructions (p less than 0.05). Proper ECA reconstruction results in long-term patency. In the patient with ipsilateral ICA occlusion, transposition of the ICA as a patch over the endarterectomized ECA offers a valid hemodynamic solution. Objective parameters are needed to identify patients with nonlateralizing symptoms who will benefit from operation.     

Outcomes associated with a transcarotid artery revascularization-centered protocol in high-risk carotid revascularizations using the ENROUTE neuroprotection system

Objective

This investigation describes the perioperative and early follow-up results associated with transcarotid artery revascularization (TCAR) in patients not participating in the Safety and Efficacy Study for Reverse Flow Used During Carotid Artery Stenting Procedure II (ROADSTER-2) registry using the ENROUTE neuroprotection system (ENPS; Silk Road Medical, Sunnyvale, Calif).

显微颈动脉内膜切除术治疗颈动脉狭窄和闭塞

目的:探讨颈动脉内膜切除术治疗颈动脉粥样硬化性狭窄和闭塞的疗效.方法2005年8月至2008年11月16例患者均经彩色超声、磁共振血管成像(MRA)、CTA、数字减影血管造影证实为中重度颈动脉狭窄,14例狭窄率为60%～99%,2例完全闭塞;12例行标准颈动脉内膜切除术,4例行外翻式颈动脉内膜切除术;2例术中放置转流管;1例术中行补片成形术.所有手术均借助显微镜完成.结果:围手术期及术后随访无卒中、短暂性脑缺血及死亡病例.术后均经彩色超声、MRA检查证实颈内动脉血流通畅,术后原症状改善或消失.1例并发消化道出血,1例围手术期有声嘶、呛水,对症治疗后症状消失,余均无并发症.结论:颈动脉内膜切除术是治疗颈动脉狭窄的有效方法,采用不同术式及技术,对不同颈动脉病变可以达到最佳治疗效果;显微手术有助于高位分叉颈动脉的显露,能有效避免颅神经损伤及其他并发症.     

Intraoperative duplex ultrasonography as an adjunct to technical excellence in 100 consecutive carotid endarterectomies

PURPOSE: To evaluate the relationship of intraoperative duplex ultrasonography (duplex) results to neurologic outcomes and restenosis among patients undergoing carotid endarterectomy (CEA). METHODS: One hundred consecutive CEAs were performed at a military medical center over 28 months. Prospectively acquired demographics, duplex results, revisions, and surgical outcomes were reviewed. RESULTS: Thirty-four percent (34 of 100) of sites were abnormal by completion duplex. Of these, 70% (24 of 34) were B-mode flap type defects located in the common carotid artery (CCA), internal carotid artery (ICA), or external carotid artery (ECA). Twenty-one percent of the defects (7 of 34) were technically unacceptable and immediately revised. Subsequently, 3 perioperative neurologic events occurred, 2 strokes and 1 transient ischemic attack (TIA), all among patients with an identified but unrepaired defect involving the ICA or CCA. This association of unrepaired defect with early stroke or TIA was significant (P = 0.02). No significant association (P >0.05) between unrepaired defects and late ipsilateral stroke or TIA or restenosis was identified. CONCLUSIONS: Intraoperative duplex scanning is a useful adjunct to CEA that can identify correctable mechanical problems. Residual elevated velocities or B-mode flaps 2 mm or greater in the ICA warrant consideration for immediate repair. Findings not requiring revision include flaps <2 mm, as well as isolated ECA defects. Prospectively validated duplex criteria are needed to further define which defects require immediate repair.     

External carotid endarterectomy in the treatment of symptomatic patients with internal carotid artery occlusion

In patients with internal carotid artery (ICA) occlusion, the external carotid artery (ECA) can be both a source of collateral flow and a pathway for emboli. We identified 11 patients with ICA occlusion and ipsilateral ECA stenosis who underwent ECA endarterectomy to determine its role in treating extracranial cerebrovascular disease. Follow-up ranged from 1–65 months, with a mean of 27 months. Seven of eight patients with unilateral disease remained symptom free. The eighth patient had recurrent symptoms that were subsequently diagnosed as hemi-Parkinsonism. Two of three patients with bilateral occlusive disease had developed non-hemispheric symptoms at 12 and 24 months, respectively; the third remains asymptomatic after extracranial-intracranial bypass. None of the seven patients who presented with amaurosis fugax had recurrent visual symptoms. ECA endarterectomy is a safe and effective operation in treating symptomatic patients with ICA occlusion, especially those with transient monocular blindness or unilateral occlusive disease. It is less effective in those patients who have diffuse bilateral occlusive disease.     

A comparative analysis of long-term mortality after carotid endarterectomy and carotid stenting

Background

The value of carotid intervention is predicated on long-term survival for patients to derive a stroke prevention benefit. Randomized trials report no significant difference in survival after carotid endarterectomy (CEA) vs carotid artery stenting (CAS), whereas observational studies of “real-world” outcomes note that CEA is associated with a survival advantage. Our objective was to examine long-term mortality after CEA vs CAS using a propensity-matched cohort.

Surgical treatment of internal carotid artery occlusion

PURPOSE: Nonoperative treatment of recent internal carotid artery (ICA) occlusion is associated with increased recurrent stroke rates. We analyzed our results of carotid endarterectomy (CEA) for treatment of symptomatic recent ICA occlusion to evaluate its feasibility, safety, and outcomes. METHODS: From 1990 to 2002, all patients with transient ischemic attack (TIA), amaurosis fugax, and minor stroke underwent duplex ultrasound (US) scanning and arteriography to confirm the diagnosis of ICA occlusion. Within 2 weeks of symptom onset, patients underwent operative exploration with attempted CEA. ICA occlusion was detected at preoperative angiography and confirmed at surgery. Patients with extensive ICA plaque not amenable to endarterectomy underwent external CEA with ICA ligation. RESULTS: Over 12 years, 87 patients with symptomatic ICA occlusion underwent 90 operations for ICA exploration. In 30 patients (18 men, 12 women) with TIA (45%), amaurosis fugax (19%), or minor stroke (36%), CEA to treat ICA occlusion was technically successful. There was 1 postoperative stroke, 2 asymptomatic internal carotid occlusions, and no restenoses (mean follow-up, 26 months; range, 1-93 months). In 57 patients (37 men, 20 women) with TIA (41%), amaurosis fugax (27%), or stroke (32%) in whom CEA was unsuccessful, external CEA was performed. In this group there were no postoperative strokes, 2 asymptomatic external carotid artery occlusions, and 1 restenosis (>70%) (mean follow-up, 22 months; range, 1-73 months). There were no late strokes in either group. CONCLUSION: Operative exploration and endarterectomy to treat symptomatic ICA occlusion is feasible and safe. Patients with symptomatic ICA occlusion should be considered candidates for CEA.     

Three-dimensional image fusion is associated with lower radiation exposure and shorter time to carotid cannulation during carotid artery stenting

Objective

Three-dimensional (3D) image fusion is associated with lower radiation exposure, contrast agent dose, and operative time during endovascular abdominal aortic aneurysm repair. Therefore, we evaluated the impact of this technology on carotid artery stenting (CAS).