Computer-derived density spectral array in detection of mild analog electroencephalographic ischemic pattern changes during carotid endarterectomy

1993 ◽  
Vol 78 (6) ◽  
pp. 884-890 ◽  
Author(s):  
Lee A. Kearse ◽  
Dean Martin ◽  
Kathleen McPeck ◽  
Maria Lopez-Bresnahan
Keyword(s):  
Cerebral Ischemia ◽  
Carotid Artery ◽  
Carotid Endarterectomy ◽  
Kappa Statistics ◽  
Content Type ◽  
Ischemic Change ◽  
Number Of Patients ◽  
Severe Group ◽  
Array Detection ◽  
Eeg Pattern

✓ The purpose of this prospective study was twofold: 1) to determine the sensitivity and specificity of computer-derived density spectral array in detecting analog electroencephalographic (EEG) ischemic pattern changes during carotid artery cross-clamping in patients undergoing carotid endarterectomy; and 2) to assess the ability of density spectral array to identify such changes in comparison with the degree and type of change seen in the analog EEG ischemic pattern. Sixteen channels of anteroposterior bipolar and two to four channels of referential electroencephalography with four channels of density spectral array were monitored simultaneously during carotid endarterectomy in 103 patients under general anesthesia. Two “observers” interpreted the density spectral array and the analog electroencephalograms, one during and immediately after the operations and the other 6 months after completion of all surgery. Analyses were conducted to establish both the number of patients with analog EEG ischemic changes and the number of ischemia events during carotid artery cross-clamping. Observer A indicated that the density spectral array identified analog EEG ischemic changes in 21 of 29 patients, for a sensitivity of 72% (specificity 99%), whereas Observer B's results showed that the density spectral array identified analog EEG ischemic changes in 16 of 27 patients, for a sensitivity of 59% (specificity 96%). Density spectral array detection of analog EEG ischemic changes based on severity classifications were 61% and 18% in the mild group, 70% and 71% in the moderate group, and 95% in the severe group, indicating a relationship between density spectral array sensitivity and severity of analog EEG ischemic change, with p = 0.02 and p = 0.004 for the two observers. The kappa statistics for observer reproducibility were highly significant, with k = 0.95 for analog EEG ischemic changes and 0.85 for density spectral array changes. It is concluded that density spectral array does not reliably detect mild analog EEG pattern changes of cerebral ischemia and is not a reliable substitute for 16-channel analog EEG monitoring of cerebral ischemia during carotid endarterectomy.

Defining thresholds for critical ischemia by using near-infrared spectroscopy in the adult brain

1998 ◽  
Vol 89 (3) ◽  
pp. 389-394 ◽  
Author(s):  
Peter J. Kirkpatrick ◽  
Joseph Lam ◽  
Pippa Al-Rawi ◽  
Piotr Smielewski ◽  
Marek Czosnyka
Keyword(s):  
Infrared Spectroscopy ◽  
Cerebral Ischemia ◽  
Carotid Artery ◽  
Carotid Endarterectomy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Adult Brain ◽  
Content Type ◽  
Signal Changes ◽  
Fine Print

Object. Signal changes in adult extracranial tissues may have a profound effect on cerebral near-infrared spectroscopy (NIRS) measurements. During carotid surgery NIRS signals provide the opportunity to determine the relative contributions from the intra- and extracranial vascular territories, allowing for a more accurate quantification. In this study the authors applied multimodal monitoring methods to patients undergoing carotid endarterectomy and explored the hypothesis that NIRS can define thresholds for cerebral ischemia, provided extracranial NIRS signal changes are identified and removed. Relative criteria for intraoperative severe cerebral ischemia (SCI) were applied to 103 patients undergoing carotid endarterectomy. Methods. One hundred three patients underwent carotid endarterectomy. An intraoperative fall in transcranial Doppler—detected middle cerebral artery flow velocity (%ΔFV) of greater than 60% accompanied by a sustained fall in cortical electrical activity were adopted as criteria for SCI. Ipsilateral frontal NIRS recorded the total difference in concentrations of oxyhemoglobin and deoxyhemoglobin (Total ΔHbdiff). Interrupted time series analysis following clamping of the external carotid artery (ECA) and the internal carotid artery (ICA) allowed the different vascular components of Total ΔHbdiff (ECA ΔHbdiff and ICA ΔHbdiff) to be identified. Data obtained in 76 patients were deemed suitable. A good correlation between %ΔFV and ICA ΔHbdiff (r = 0.73, p < 0.0001) was evident. Sixteen patients (21%) fulfilled the criteria for SCI. All patients who demonstrated an ICA ΔHbdiff of greater than 6.8 µmol/L showed SCI, and in two patients within this group nondisabling watershed infarction developed, as seen on postoperative computerized tomography scans. No patient with an ICA ΔHbdiff less than 5 µmol/L exhibited SCI or suffered a stroke. Within the resolution of the criteria used an ICA ΔHbdiff threshold of 6.8 µmol/L provided 100% specificity for SCI, whereas an ICA ΔHbdiff less than 5 µmol/L was 100% sensitive for excluding SCI. When Total ΔHbdiff was used without removing the ECA component, no thresholds for SCI were apparent. Conclusions. Carotid endarterectomy provides a stable environment for exploring NIRS-quantified thresholds for SCI in the adult head.

Anterior communicating artery collateral flow protection against ischemic change during carotid endarterectomy

1993 ◽  
Vol 79 (3) ◽  
pp. 379-382 ◽  
Author(s):  
Maria V. Lopez-Bresnahan ◽  
Lee A. Kearse ◽  
Paulino Yanez ◽  
Tina I. Young
Keyword(s):  
Cerebral Ischemia ◽  
Carotid Artery ◽  
Carotid Endarterectomy ◽  
Cerebral Arteries ◽  
Artery Occlusion ◽  
Carotid Artery Occlusion ◽  
Anterior Communicating Artery ◽  
Collateral Flow ◽  
Content Type ◽  
Carotid Circulation

✓ The purpose of this study was to determine whether preoperative angiographic patterns of collateral cerebral blood flow correlate with protection against intraoperative electroencephalographic (EEG) evidence of cerebral ischemia caused by carotid artery cross-clamping during carotid endarterectomy. Previous studies have shown that contralateral carotid artery occlusion and intracranial stenoses are associated with cerebral ischemia during carotid endarterectomy; however, the angiographic collateral flow patterns associated with cerebral ischemia have not been identified. This paper reports a retrospective study of 67 patients who underwent two- to four-vessel cerebral angiography followed by carotid endarterectomy with 16-channel EEG monitoring. The angiograms were reviewed for extracranial occlusive disease and collateral flow patterns, and the EEG recordings were analyzed for ischemic changes during carotid artery cross-clamping. Statistical analysis was by Fisher's exact test. Cross-filling of the anterior and middle cerebral arteries from the contralateral carotid artery through the anterior communicating artery correlated with a decreased incidence of EEG ischemic changes. Only 21% of patients with this collateral flow pattern showed ischemic changes compared to 50% of patients without this pattern (p < 0.03). Three angiographic findings occurring in combination on the side contralateral to surgery correlated with EEG ischemia: 1) occlusion of the contralateral internal carotid artery (five of seven or 71%, p < 0.03); 2) collateral flow from the external carotid circulation to the internal carotid circulation via the ophthalmic artery; and 3) collateral flow from the posterior circulation to the contralateral anterior circulation via the posterior communicating artery. The data presented here corroborate the correlation between contralateral carotid artery occlusion and cerebral ischemia during carotid endarterectomy. They also demonstrate that cross-filling of the anterior and middle cerebral arteries by the contralateral carotid artery protects against such ischemia. This collateral flow may serve as an indicator of tolerance to carotid artery cross-clamping.

Cerebral monitoring by means of oximetry and somatosensory evoked potentials during carotid endarterectomy

1998 ◽  
Vol 89 (4) ◽  
pp. 533-538 ◽  
Author(s):  
Hun Cho ◽  
Edwin M. Nemoto ◽  
Howard Yonas ◽  
Jeffrey Balzer ◽  
Robert J. Sclabassi
Keyword(s):  
Cerebral Ischemia ◽  
Carotid Artery ◽  
Evoked Potentials ◽  
Carotid Endarterectomy ◽  
Somatosensory Evoked Potentials ◽  
External Carotid Artery ◽  
Cerebral Oximetry ◽  
External Carotid ◽  
Content Type ◽  
Fine Print

Object. Cerebral ischemia that occurs during carotid endarterectomy is commonly monitored by means of somatosensory evoked potentials (SSEPs) and electroencephalography (EEG). The authors conducted this study to determine whether cerebral ischemia could also be reliably detected by cerebral oximetry. Methods. Twenty-nine patients who underwent carotid endarterectomy were monitored by means of SSEPs, EEG, and cerebral oximetry with a model NIRO500 (20 patients) or INVOS3100A (nine patients) oximeter. Changes in amplitude of SSEPs were graded as follows: 0, no change; 1, decrease of less than 50%; 2, decrease of greater than 50%; and 3, 100% decrease. As measured with the NIRO500 oximeter, closing the common caro-tid artery decreased mean oxyhemoglobin levels twice as much (p < 0.005) in the group with SSEPs of 1 to 3 (−13.11 ± 5.59 µM [mean ± standard deviation], 12 patients) as in the group with SSEPs of 0 (−6.22 ± 5.59 µM, eight patients). The rise in deoxyhemoglobin was also greater (p < 0.05). Two of nine patients monitored with the INVOS3100A oximeter had SSEPs of 1 and 3, and their regional saturation of oxygen (rSO2) values fell by −11.50 and −11.51, respectively. In the remaining seven patients with SSEPs of 0, the rSO2 ranged between −2.00 and −6.10 with no overlap with the group with SSEPs of 1 to 3. The increase in oxyhemoglobin monitored using the NIRO500 oximeter and rSO2 monitored using the INVOS3100A machine after opening the external carotid artery was less than that seen after opening the internal carotid artery. Both types of oximeters could detect cerebral ischemia but whereas false negatives occurred with the NIRO500, none was observed with the INVOS3100A. Extracranial contamination was also four times less frequent with the INVOS3100A than with the NIRO500 monitor. Conclusions. The results indicate that at least as measured with the INVOS3100A instrument, a decrease in rSO2 of −10 or more or a decrease below an rSO2 of 50 is indicative of cerebral ischemia of sufficient severity to decrease the amplitude of SSEPs.

Atheromatous pseudo-occlusion of the internal carotid artery

1980 ◽  
Vol 52 (6) ◽  
pp. 782-789 ◽  
Author(s):  
Laligam N. Sekhar ◽  
Roberto C. Heros ◽  
Preston R. Lotz ◽  
Arthur E. Rosenbaum
Keyword(s):  
Carotid Artery ◽  
Internal Carotid Artery ◽  
Contrast Medium ◽  
Carotid Endarterectomy ◽  
Internal Carotid ◽  
Contrast Material ◽  
Atheromatous Plaque ◽  
Content Type ◽  
Specialized Technique ◽  
Logical Treatment

✓ In the past year, three patients were referred for microvascular bypass surgery for relief of symptoms secondary to an apparently occluded internal carotid artery (ICA). Careful review of the late films of their initial arteriographic series or repeat arteriography with a specialized technique revealed a thin trickle of contrast medium flowing antegrade through a region of extreme stenosis. This thin line of contrast material ascended slowly to meet the column of contrast medium in the cavernous carotid segment that was filling by collateral circulation. Surgical exploration of the neck in these patients revealed a patent but collapsed ICA distal to a localized atheromatous plaque. These patients have been asymptomatic following carotid endarterectomy. This distinctive angiographic appearance may be described as “atheromatous pseudo-occlusion.” Once recognized, carotid endarterectomy is the logical treatment of choice.

Adverse effects of prolonged hyperventilation in patients with severe head injury: a randomized clinical trial

1991 ◽  
Vol 75 (5) ◽  
pp. 731-739 ◽  
Author(s):  
J. Paul Muizelaar ◽  
Anthony Marmarou ◽  
John D. Ward ◽  
Hermes A. Kontos ◽  
Sung C. Choi ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Control Group ◽  
Content Type ◽  
Cerebral Vasoconstriction ◽  
Number Of Patients ◽  
Severity Of Injury ◽  
Head Injured ◽  
Injured Patients ◽  
To Receive

✓ There is still controversy over whether or not patients should be hyperventilated after traumatic brain injury, and a randomized trial has never been conducted. The theoretical advantages of hyperventilation are cerebral vasoconstriction for intracranial pressure (ICP) control and reversal of brain and cerebrospinal fluid (CSF) acidosis. Possible disadvantages include cerebral vasoconstriction to such an extent that cerebral ischemia ensues, and only a short-lived effect on CSF pH with a loss of HCO3− buffer from CSF. The latter disadvantage might be overcome by the addition of the buffer tromethamine (THAM), which has shown some promise in experimental and clinical use. Accordingly, a trial was performed with patients randomly assigned to receive normal ventilation (PaCO2 35 ± 2 mm Hg (mean ± standard deviation): control group), hyperventilation (PaCO2 25 ± 2 mm Hg: HV group), or hyperventilation plus THAM (PaCO2 25 ± 2 mm Hg: HV + THAM group). Stratification into subgroups of patients with motor scores of 1–3 and 4–5 took place. Outcome was assessed according to the Glasgow Outcome Scale at 3, 6, and 12 months. There were 41 patients in the control group, 36 in the HV group, and 36 in the HV + THAM group. The mean Glasgow Coma Scale score for each group was 5.7 ± 1.7, 5.6 ± 1.7, and 5.9 ± 1.7, respectively; this score and other indicators of severity of injury were not significantly different. A 100% follow-up review was obtained. At 3 and 6 months after injury the number of patients with a favorable outcome (good or moderately disabled) was significantly (p < 0.05) lower in the hyperventilated patients than in the control and HV + THAM groups. This occurred only in patients with a motor score of 4–5. At 12 months posttrauma this difference was not significant (p = 0.13). Biochemical data indicated that hyperventilation could not sustain alkalinization in the CSF, although THAM could. Accordingly, cerebral blood flow (CBF) was lower in the HV + THAM group than in the control and HV groups, but neither CBF nor arteriovenous difference of oxygen data indicated the occurrence of cerebral ischemia in any of the three groups. Although mean ICP could be kept well below 25 mm Hg in all three groups, the course of ICP was most stable in the HV + THAM group. It is concluded that prophylactic hyperventilation is deleterious in head-injured patients with motor scores of 4–5. When sustained hyperventilation becomes necessary for ICP control, its deleterious effect may be overcome by the addition of THAM.

Neurosurgical applications of ocular pneumoplethysmography

1981 ◽  
Vol 54 (5) ◽  
pp. 588-595 ◽  
Author(s):  
William F. Bingham
Keyword(s):  
Standard Deviation ◽  
Carotid Artery ◽  
Intracranial Aneurysm ◽  
Carotid Endarterectomy ◽  
Contralateral Side ◽  
Artery Occlusion ◽  
Carotid Artery Occlusion ◽  
Content Type ◽  
Final Adjustment ◽  
Fine Print

✓ Ocular pneumoplethysmography (OPG), a semiautomated form of suction ophthalmodynamometry, was used to evaluate and follow 15 patients who underwent carotid endarterectomy and two patients in whom gradual carotid artery occlusion was performed for inoperable intracranial aneurysm. Postoperative corrected ophthalmic arterial pressures (COAP's) on the operated side in the carotid endarterectomy patients averaged 12.5 mm Hg higher than before surgery, the standard deviation being 4.9 mm Hg for clinically stable patients. There was no significant change in COAP on the contralateral side. Several problems were encountered in closing down carotid clamps, the most potentially serious being a precipitous fall in COAP with the final adjustment. The current uses of OPG and similar techniques are reviewed, and potential neurosurgical applications are discussed.

Cerebral hyperperfusion following carotid endarterectomy

1987 ◽  
Vol 66 (6) ◽  
pp. 824-829 ◽  
Author(s):  
Torben Schroeder ◽  
Henrik Sillesen ◽  
Ole Sørensen ◽  
Hans Christian Engell
Keyword(s):  
Carotid Artery ◽  
Carotid Endarterectomy ◽  
Pressure Ratio ◽  
Ipsilateral Hemisphere ◽  
Content Type ◽  
High Pressure Ratio ◽  
Cerebral Hyperperfusion ◽  
Postoperative Hypertension ◽  
Serial Measurements ◽  
Fine Print

✓ Serial measurements of cerebral blood flow (CBF) were performed in 56 patients before and one to four times after uncomplicated carotid endarterectomy. The findings were related to the ratio between internal carotid artery (ICA) and common carotid artery (CCA) mean pressures. Within the 1st postoperative day CBF increased by a median of 37% in the ipsilateral and 33% in the contralateral hemisphere. Later recordings showed a gradual return of CBF toward the preoperative level. Sixteen patients with an ICA/CCA pressure ratio below 0.7 showed a significantly more pronounced and longer-lasting flow increase than did 40 patients with a ratio above this level. On Day 1, the median CBF increase in the ipsilateral hemisphere was 61% and 24% in the two groups, respectively (p < 0.01). A significant improvement in side-to-side asymmetry, resulting from a higher gain in the ipsilateral hemisphere, occurred in the low pressure ratio group, while the hemispheric asymmetry on average was unchanged in the high pressure ratio group. This relative hyperemia was most pronounced 2 to 4 days following reconstruction. The marked hyperemia, absolute as well as relative, in patients with a low ICA/CCA pressure ratio suggests a temporary impairment of autoregulation. Special care should be taken to avoid postoperative hypertension in such patients, who typically have preoperative hypoperfusion, to avoid the occurrence of cerebral edema or hemorrhage.

Measurement of CBF and carotid artery pressure compared with cerebral angiography in assessing collateral blood supply after carotid ligation

1977 ◽  
Vol 46 (2) ◽  
pp. 185-196 ◽  
Author(s):  
Khalil Jawad ◽  
J. Douglas Miller ◽  
David J. Wyper ◽  
John O. Rowan
Keyword(s):  
Carotid Artery ◽  
Internal Carotid Artery ◽  
Internal Carotid ◽  
Carotid Angiography ◽  
Content Type ◽  
Artery Pressure ◽  
Carotid Ligation ◽  
Number Of Patients ◽  
Carotid Aneurysms ◽  
The Brain

✓ Angiographic assessment of collateral circulation to the brain at the circle of Willis was compared with measurements of cerebral blood flow (CBF) and internal carotid artery pressure during temporary carotid clamping in the prediction of tolerance of unilateral carotid ligation as treatment for intracranial carotid aneurysms in 92 patients. From CBF studies it was predicted that a substantial number of patients (27%) would suffer severe cerebral ischemia if carotid ligation were carried out. No single angiographic feature provided this predictive information. Bilateral fetal type of posterior communicating arteries were associated with significantly lower carotid artery back pressure on temporary carotid occlusion, and unilateral absence of posterior communicating arteries was related to lower CBF, but neither feature was associated with a significant reduction in the rate of successful carotid ligation. We believe that preliminary percutaneous digital carotid compression with electroencephalographic monitoring, followed by intraoperative measurement of the change in regional CBF and internal carotid artery pressure during temporary carotid clamping provides a safe method of selecting patients for carotid ligation. Carotid angiography with or without contralateral carotid compression is of little value in this respect.

Carotid artery angioplasty and use of stents in high-risk patients with contralateral occlusions

1999 ◽  
Vol 90 (6) ◽  
pp. 1031-1036 ◽  
Author(s):  
Robert A. Mericle ◽  
Stanley H. Kim ◽  
Giuseppe Lanzino ◽  
Demetrius K. Lopes ◽  
Ajay K. Wakhloo ◽  
...  
Keyword(s):  
High Risk ◽  
Carotid Artery ◽  
Carotid Endarterectomy ◽  
Stent Placement ◽  
Death Rate ◽  
Minor Stroke ◽  
Content Type ◽  
Symptomatic Carotid ◽  
Fine Print

Object. The risks associated with carotid endarterectomy (CEA) are increased in the presence of contralateral carotid artery (CA) occlusion. The 30-day stroke and death rate for patients in the North American Symptomatic Carotid Endarterectomy Trial (NASCET) who had contralateral CA occlusion was 14.3%. The authors analyze their experience with angioplasty and/or stent placement in patients with contralateral CA occlusion to determine the safety and efficacy of endoluminal revascularization in this subgroup.Methods. Twenty-six procedures were evaluated in 23 patients with high-grade CA stenosis and contralateral CA occlusion. The first 15 procedures were evaluated retrospectively, and the next 11 prospectively. All patients had severe medical comorbidities and were considered too high risk for CEA, even without considering the contralateral occlusion. Clinical follow-up review was performed an average of 18 months later (median 15 months).Conclusions. The average ipsilateral CA stenosis according to NASCET criteria was 78% preprocedure and 5% postprocedure. There were no changes in neurological or functional outcome immediately postoperatively in any patient. The 30-day postoperative stroke and death rates were zero. However, there was one symptomatic femoral hematoma that resolved without surgery. At follow up, there were three patients who had suffered stroke or death. One patient died secondary to respiratory arrest at 2 months; one died secondary to prostate carcinoma at 12 months; and one patient experienced a minor stroke contralateral to the treated artery at 41 months. Despite the substantial preoperative risk factors in patients in this series, the 30-day stroke and death rate for angioplasty and/or stent placement appears to be lower than that of CEA in patients with contralateral occlusions.

Carotid endarterectomy performed after progressive carotid stenosis following angioplasty and stent placement

1997 ◽  
Vol 87 (6) ◽  
pp. 940-943 ◽  
Author(s):  
Fernando L. Vale ◽  
Winfield S. Fisher ◽  
William D. Jordan ◽  
Cheryl A. Palmer ◽  
Jiri Vitek
Keyword(s):  
Carotid Artery ◽  
Carotid Endarterectomy ◽  
Stent Placement ◽  
Vessel Wall ◽  
Pathological Examination ◽  
Metallic Stent ◽  
Content Type ◽  
Symptomatic Disease ◽  
Ica Stenosis ◽  
Fine Print

✓ Carotid endarterectomy (CEA) is the treatment of choice for asymptomatic and symptomatic disease causing greater than 60% internal carotid artery (ICA) stenosis. Recently, percutaneous transluminal angioplasty (PTA) with stent placement has been investigated as a therapeutic option for the treatment of ICA stenosis. In this report the authors document CEA performed after PTA with stent placement and describe the pathological findings. A standard CEA was performed. The surgical intervention was more difficult secondary to the following variables: the length of the exposure necessary to dissect out the metallic stent, the difficulty with opening and cutting the artery, and the care required to remove the stent to avoid vessel wall perforation. Pathological examination of the specimen demonstrated classic atherosclerotic changes revealing persistence of native disease. The metallic stent was embedded within the plaque. Many questions remain unanswered regarding the physiological and biological changes that occur in the carotid vessel wall after PTA with stent placement. It is concluded that CEA of a stent-containing carotid artery is feasible and should be considered as an alternative when recurrent stenosis occurs after PTA.

Sign in / Sign up

Export Citation Format

Share Document