Varying impact of common carotid artery digital compression and internal carotid artery balloon test occlusion on cerebral hemodynamics

BACKGROUND: The purpose of this study was to compare the cerebral hemodynamic changes brought about by common carotid artery (CCA) digital compression and angiographic internal carotid artery (ICA) balloon occlusion. METHODS: Bilateral transcranial Doppler ultrasonographic monitoring of the middle cerebral artery blood velocity (VMCA) was performed in 12 subjects with neck neoplasms or traumatic carotid-cavernous fistulas. The MCA pulsatility index (PIMCA) and hemodynamic tension (Uhem MCA) were calculated. RESULTS: Common carotid artery compression provoked the largest drop in ipsilateral VMCA, PIMCA, and Uhem MCA. Common carotid artery compression caused a steal of blood from the intra- to the extracranial circulation, with the discrepancy in hemodynamic findings between CCA and ICA test occlusions being dependent on the quantity of reversed ipsilateral ICA blood flow. CONCLUSION: If the carotid artery is to be sacrificed, permanent ICA closure is the procedure of choice with respect to the occurrence of cerebral ischemic lesions in patients with neck neoplasms and ICA flow reversal during CCA compression.     

Cerebral haemodynamics in internal carotid artery trial occlusion

The purpose of this study was to analyse the cerebral haemodynamic changes brought about by trial occlusion of the internal carotid artery (ICA). Sixteen patients with surgically inaccessible cerebral aneurysms, carotid cavernous fistulas or neck neoplasms were monitored with transcranial Doppler ultrasonography (TCD) during 90-120 s angiographic ICA balloon occlusion or ICA closure with a Selverstone clamp. The blood velocity (V) was registered continuously in both middle cerebral arteries (MCA) while the pulsatility index (PIMCA) and haemodynamic tension (Uhem MCA) were calculated. ICA closure led to an instantaneous drop in the ipsilateral VMCA, PIMCA and Uhem MCA. The VMCA thereafter increased gradually until reaching a stable level. The subjects were grouped into those with initial drops in VMCA to > or = 60% of pre-occlusion value (group 1) and those that fell to < 60% (group 2), respectively. In group 1 autoregulatory mechanisms made the PIMCA decline further, while the Uhem MCA remained unaltered during ICA closure. In group 2, however, the PIMCA did not change further, while the Uhem MCA increased slightly. The cerebral haemodynamic features during ICA test occlusion were thus essentially different in the two groups. On re-opening the ICA, there was an overshoot in VMCA and Uhem MCA. Contralaterally, the VMCA was increased during ICA occlusion. Seven of the patients later had their ICA closed permanently. While none of five group 1 patients developed haemodynamic complications, two group 2 individuals experienced haemodynamic stroke. Assuming ICA sacrifice is feasible when test occlusion results in an ipsilateral initial reduction in VMCA to > or = 60% of pre-occlusion value, the corresponding limit for the Uhem MCA is > or = 40%. In the pre-operative evaluation of the haemodynamic risk related to ICA loss, TCD emerges as a reliable method. It also seems to allow for the reduction of test occlusion time to 90-120 s.     

Predicting hemodynamic ischemia by transcranial Doppler monitoring during therapeutic balloon occlusion of the internal carotid artery

PURPOSE: Our objective was to evaluate the sensitivity of transcranial Doppler (TCD) sonographic monitoring during permanent balloon occlusion of the internal carotid artery (ICA) in predicting hemodynamic ischemia. METHODS: Thirty-two consecutive patients underwent controlled therapeutic balloon occlusion of the ICA. Selection criteria included assessment of the circle of Willis by compression angiography, clinical tolerance during a 20-minute test occlusion, and TCD monitoring of the ipsilateral middle cerebral artery. The mean blood flow velocity (MBFV) (n = 32) and pulsatility index (PI) (n = 28) were recorded. In 25 patients, MBFV changes upon motor stimulation were recorded before and after ICA occlusion. RESULTS: Twenty-eight (88%) of the patients had no complications. Three patients suffered delayed symptoms 30 minutes to 20 hours after balloon detachment. Two of these patients recovered spontaneously within 1 day, the other improved after extracranial/intracranial (EC/IC) bypass surgery. One patient, who did not tolerate the test occlusion, suffered a hemodynamic stroke despite EC/IC bypass before permanent balloon occlusion. No embolic complications occurred. The mean MBFV reduction was 20% (range, 0% to 55%); the mean PI reduction was 20% (range, 0% to 56%). No complications occurred in patients who had mild MBFV and PI reduction (30% or less, n = 21). All three patients with severe MBFV or PI reduction (> 50%) had neurologic symptoms. Among those with moderate MBFV or PI reduction (30% to 50%, n = 8), symptoms developed in only one patient who had moderate reduction of both MBFV (33%) and PI (38%). Motor vasoreactivity showed wide variation and was markedly reduced in two symptomatic patients. CONCLUSION: TCD monitoring reflects changes in cerebral hemodynamics after therapeutic balloon occlusion of the ICA. MBFV and PI reductions under 30% are highly predictive of clinical tolerance. A reduction of more than 50% may be a critical threshold for the occurrence of symptoms; in such cases, EC/IC bypass should be considered before proceeding with permanent balloon occlusion.     

Avid uptake of technetium-99m-HMPAO by an intracranial plasmacytoma during carotid balloon test occlusion

A 56-yr-old woman was evaluated for removal of a tumor at the base of the skull. A test to determine the risk of carotid artery sacrifice was performed prior to surgery using carotid balloon occlusion of the left internal carotid artery and 99mTc-HMPAO perfusion scintigraphy during the occlusion. An unusual intense focus of increased uptake was seen at the site of the primary tumor in the left cavernous sinus. The tumor, found to be plasmacytoma at surgery, demonstrated only mild washout from 30 min to 2 hr after administration of 99mTc-HMPAO, with a tumor-to-cerebellum ratio of 1.6 and 1.5, respectively, and a tumor-to-contralateral cranial ratio of 2.5 and 2.4, respectively. Intracranial plasmacytoma shows good response to radiation therapy, and the differentiation of this tumor from other neoplasms is pertinent to the mode of treatment and surgical approach. Technetium-99m-HMPAO SPECT imaging may be a useful tool in distinguishing these tumors from other neoplasms at the base of the skull.     

Relationship between the flow pattern and vasomotor reactivity in the ophthalmic artery, siphon and vessels within the circle of Willis in the unilateral internal carotid artery occlusion

The aim was to study a relationship between the flow pattern in the ophthalmic artery (OA), the siphon and vessels within the circle of Willis. 27 patients, 22 males and 5 females, mean age 63 +/- 15 years (SD) with unilateral occlusion of the internal carotid artery (ICA) were examined by 3-dimensional Transcranial Doppler scanner. Flow signals from the OA, the siphon and intracranial vessels were registered before and after i.v. injection of 1 g acetazolamide. Pathological flow pattern was found in 18 patients in the OA on the occluded side consisting of 12 retrograde and 6 isoelectric flow directions. After acetazolamide injection retrograde systolic velocities (SV) increased significantly (p < 0.01), but anterograde velocities remained unchanged as did 3 isoelectric flow patterns, 2 turned to retrograde and one to anterograde flow direction. In the siphon lower resting anterograde mean velocities (MV) were found on both sides (p < 0.05) compared to normal subjects. Six patients had the same retrograde flow as in the OA. After acetazolamide MV in the siphon increased (p < 0.01) only on the nonoccluded side. Baseline retrograde ophthalmic SV and MV in the siphon correlated (p < 0.01 and p < 0.05 respectively) with MV in the middle cerebral artery (MCA) according to linear regression analysis (r = 0.78 and 0.59 respectively). All patients, having impaired vasomotor reactivity (VMR) < or = 11% in the anterior cerebral artery (ACA) on the occluded side, had pathological flow pattern in the OA. Patients with greatest difference (delta) between MV in the ACA on the nonoccluded and occluded side had a tendency to anterograde flow (r = 0.56, p < 0.05). Pulsative index (PI) in the ACA on the occluded side was lowest in the category with retrograde flow in the OA (0.67 +/- 0.14) and differed (p < 0.05) from normals and from the category with isoelectric and anterograde flow. Correlation of retrograde flow direction in the OA and baseline MV in the MCA and low PI in the ACA on the occluded side indicates a supplying ophthalmic collateral to the anterior brain circulation. Impaired VMR in the ACA on the occluded side in connection with pathological flow pattern in the OA may reflect an exhaustion of the ACA as a supplying vessel.     

Newly developed blocking balloon catheter for PTA of internal carotid artery

We have developed a new blocking balloon system for percutaneous transluminal angioplasty (PTA) of the internal carotid artery (ICA). A latex balloon (BALT) is attached on the top of a Superselector infusion-type catheter (TORAY) which is used as a blocking balloon catheter. It can be navigated into the distal part of the ICA under torque control as well as flow control by withdrawing the core wire. Our PTA procedure is as follows, 1) insert the sheath catheter 8-9 F in size, 2) insert the PTA balloon catheter (Accent balloon, Cook) with a blocking balloon catheter through the sheath catheter, 3) navigate the blocking balloon into the distal part of the ICA, 4) introduce the PTA balloon to the stenotic portion after occlusion of the distal ICA by the blocking balloon, 5) PTA, 6) wash the lumen of the ICA with saline, 7) deflate the blocking balloon and withdraw the system. We performed PTA for 5 ICA lesions in 4 cases and got successful dilatations for all of them without complications. Our blocking balloon system is useful for performing the PTA of the ICA safely.     

Bilateral optic disk pallor after unilateral internal carotid artery occlusion

Bilateral pallor of the optic disks was observed in a 52-year-old man after dissection of an internal carotid artery. Diffuse pallor of the ipsilateral optic disk reflected infarction of the ipsilateral optic nerve and "bow-tie" atrophy of the contralateral optic disk reflected infarction of the ipsilateral optic tract. The findings were due to an occlusion of the internal carotid artery proximal to the origin of the ophthalmic artery, resulting also in insufficiency in the area of supply of the anterior choroidal artery.     

Thrombolytic therapy in acute occlusion of the intracranial internal carotid artery bifurcation

PURPOSE: To evaluate efficacy and clinical benefit of early thrombolytic therapy in intracranial internal carotid artery occlusion. METHODS: Thirty-two patients (mean age, 56 years) with acute intracranial internal carotid artery occlusion were studied clinically and with CT and angiography before and after thrombolytic therapy with intravenous alteplase (n = 16), superselective intraarterial alteplase (n = 8), and superselective intraarterial urokinase (n = 8). RESULTS: Initial CT showed a large parenchymal hypodensity in 11 (34%) patients, a small hypodensity in 15 (47%) patients, and no hypodensity in 6 (19%) patients. Recanalization after thrombolytic therapy was observed in 4 patients (12.5% in each treatment group). Follow-up CT showed six hemorrhagic infarcts and four parenchymal hematomas unrelated to recanalization, alteplase, or urokinase administration, but commonly associated with intraarterial treatment. Clinical outcome was fatal in 53%, poor in 31%, and moderate or good in 16% of the patients. Outcome was equal in different treatment groups and closely linked to both the quality of leptomeningeal collaterals and the extent of parenchymal hypodensity on the first CT. CONCLUSION: Because intravenous or intraarterial treatment with alteplase or urokinase fails to recanalize the vascular obstruction, it does not improve the prognosis of intracranial internal carotid artery occlusion over that of the natural course. Improved results may be possible with novel recanalization techniques.     

Carotid artery balloon test occlusion: combined clinical evaluation and xenon-enhanced computed tomographic cerebral blood flow evaluation without patient transfer or balloon reinflation: technical note

OBJECTIVE: Clinical evaluation was combined with xenon-enhanced computed tomographic (CT) cerebral blood flow (CBF) evaluation during carotid artery balloon test occlusion (BTO), without patient transfer from the angiography suite to the CT scanner or balloon reinflation. TECHNIQUE: Thirteen patients underwent carotid artery BTO. Placement of temporary occlusion balloons was performed with patients positioned on the CT scanner table. If neurological testing revealed no changes within 10 minutes after balloon inflation, patients were positioned within the CT scanner gantry for xenon-enhanced CT CBF evaluation. CBF evaluations were begun 12 to 15 minutes after balloon inflation and required 8 minutes for completion. After completion of CBF evaluation, neurological testing continued during 30 minutes of arterial occlusion. RESULTS: One patient did not tolerate BTO, with the development of reversible hemiparesis. Reliable CBF data were not obtained because of patient motion in one case. Eleven patients clinically tolerated BTO and completed CBF evaluation. For five patients, xenon-enhanced CT scanning revealed no regions with CBF of less than 30 ml/100 g/min. For four patients, xenon-enhanced CT scanning revealed small regions with CBF of less than 30 ml/100 g/min within the anterior frontal lobe on the occluded side. For two patients, ipsilateral CBF decreased dramatically during BTO, with CBF in many regions of less than 30 ml/100 g/min and in some of less than 20 ml/100 g/min. CONCLUSION: Xenon-enhanced CT CBF evaluation can be combined with clinical testing during BTO without patient transfer, balloon reinflation, or increases in the duration of the procedure. We recognize that the value of CBF evaluation during BTO remains to be proven; our technique does, however, eliminate abbreviated clinical neurological evaluation, patient transfer, and balloon reinflation, which were previously associated with the use of xenon-enhanced CT CBF evaluation during carotid artery BTO.     

Embolization with temporary balloon occlusion of the internal carotid artery and in vivo proton spectroscopy improves radical removal of petrous-tentorial meningioma

A highly vascular petroclival meningioma supplied by tentorial branches of the internal carotid artery was embolized by temporary balloon occlusion of the parent vessel distal to the tumor, followed by obliteration of the tumor vascularity with polyvinyl alcohol particles. Subsequently, in vivo proton spectroscopy showed necrosis of a large portion of the tumor and helped determine the timing of surgery. Both innovative techniques considerably facilitated the subsequent radical excision of the tumor with no neurological morbidity.     

Asymptomatic angiographic occlusion of the internal carotid artery: an indication for emergency endarterectomy

A 56-year-old man had retinal artery embolization from a carotid artery atheroma. Complete occlusion of the internal carotid artery occurred during cerebral angiography, but the patient developed no acute symptoms of cerebral ischemia. The patient immediately underwent emergency carotid endarterectomy which he tolerated well, and follow-up angiography nine days later demonstrated continued patency. The patient has remained neurologically unchanged.     

Dynamic response of cochlear blood flow to occlusion of anterior inferior cerebellar artery in guinea pigs

In this study we investigated the autoregulation and hemodynamics of cochlear blood flow (CBF) as measured by laser-Doppler flowmetry. When the anterior inferior cerebellar artery was clamped, CBF decreased approximately 40% (not to "biological zero"), followed by a gradual increase. When the clamp was released, CBF quickly increased to as much as 167% of the baseline level and then slowly returned to baseline. We assume that the dynamic CBF response to anterior inferior cerebellar artery clamping reflects primarily a combination of passive elastic properties of the cochlear vessels and active autoregulatory mechanisms. The decrease portion of the negative phase and the increase portion of the positive phase reflect mainly passive behavior, static compliance, and resistance of vessels, whereas the slow exponential negative and positive changes indicate an active response of vessels: an autoregulatory mechanism based on compensatory vascular dilation and constriction. Our preliminary data show a very strong CBF autoregulatory response to a change in intravascular pressure. Sympathetic stimulation can enhance this autoregulation, and CO2 inhalation promotes compensatory dilation and inhibits compensatory vascular constriction.     

Endovascular treatment of acute thrombotic occlusion of the cervical internal carotid artery associated with embolic occlusion of the middle cerebral artery: case report

A 68-year-old man with acute, total thrombotic occlusion of the right cervical internal carotid artery, associated with embolic occlusion of the ipsilateral middle cerebral artery, was treated by the endovascular approach, i.e., intra-arterial fibrinolysis and balloon angioplasty. Endovascular treatment for a totally occluded internal carotid artery is indicated in the very early stage where there is no thrombus or a short thrombus that can be evacuated. Fibrinolysis of the associated embolus in the middle cerebral artery, if any, can be done in the same session, enabling an early restoration of the blood flow.