Internal Carotid Artery Stump Pressure Research Articles

Evaluation of brain collateral circulation by the transcranial color Doppler-guided Matas' test.

For the determination of the indication for reconstruction of the carotid artery in patients with head and neck cancer, a color Doppler-guided Matas' test was performed to examine brain collateral circulation and blood flow of the middle cerebral artery (MCA) and internal carotid artery (ICA). Both SSA-270A convex (3.75 MHz) and linear (3.75 MHz and 2.5 MHz) array probes (Toshiba Co, Ltd) were used for this investigation. A temporary occlusion test (60 seconds) by digital pressure on the common carotid artery was performed on 30 patients with head and neck cancer. The results were classified into four groups according to the relative flow volume (percent blood flow volume before the test) of the MCA: group A, with a flow volume of 87% or more; group B, with a flow volume between 72% and 86%; group C, with a flow volume between 57% and 71%; and group D, with a flow volume of 56% or less. The relative flow volume of the MCA was correlated with the ICA stump pressure and single photon emission computed tomography during a balloon Matas' test (ICA occlusion). This test seems to be useful in predicting the risk of carotid resection without reconstruction and in determining the indication for reconstruction of the carotid artery.

Clinical observations on the effect of carotid artery occlusion on cerebral blood flow mapped by xenon computed tomography and its correlation with carotid artery back pressure

Xenon computed tomographic cerebral blood flow mapping was correlated with internal carotid artery stump pressures and clinical neurologic assessment during temporary internal carotid artery occlusion. One hundred fourteen patients with skull base tumors or intracranial aneurysms potentially requiring carotid resection or ligation underwent angiography, xenon CT cerebral blood flow mapping, and internal carotid artery blood pressure monitoring. The internal carotid artery was then temporarily occluded with a balloon catheter, stump pressure was measured through the catheter, and the xenon CT cerebral blood flow mapping was repeated. Adequate xenon CT cerebral blood flow was defined as >30 cc/100 gm/min. All patients had normal xenon CT cerebral blood flow before internal carotid artery occlusion. During internal carotid artery occlusion, xenon CT cerebral blood flow was found to be normal (group I, 40 patients), globally reduced but still within the normal range (group II, 50 patients), or low in the distribution of the ipsilateral middle cerebral artery (group III, 13 patients). With balloon occlusion, an immediate neurologic deficit developed in 11 patients (9%) requiring deflation of the balloon preceding xenon CT cerebral blood flow measurement (group IV). In group I internal carotid artery blood pressure was 128 mm Hg. (range 85 to 171 mm Hg) with stump pressure 86 mm Hg (range 46 to 125 mm Hg). In group II internal carotid artery blood pressure was 130 mm Hg. (range 78 to 199 mm Hg), with stump pressure 86 mm Hg (range 31 to 150 mm Hg). In group III internal carotid artery blood pressure was 135 mm Hg (range 95 to 194 mm Hg) with stump pressure 64 mm Hg (range 37 to 106 mm Hg). In group IV internal carotid artery blood pressure was 117 mm Hg (range 90 to 148 mm Hg), with stump pressure 62 mm Hg (range 23 to 100 mm Hg) p < 0.01 for stump pressure groups I and II versus III and IV. During subsequent operations one of the 23 patients in groups I and II requiring carotid occlusion or ligation had a stroke, but four of five patients (80%) in groups III and IV had strokes after internal carotid artery occlusion or resection. Although stump pressure correlates with xenon CT cerebral blood flow mapping, the wide range precludes its use alone as an absolute predictor of adequate cerebral blood flow after carotid occlusion. In addition, xenon CT cerebral blood flow mapping and trial internal carotid artery balloon occlusion are of value in predicting the hemodynamic consequences of carotid ligation.

A Comparison of Computerized EEG with Internal Carotid Artery Stump Pressure for Detection of Ischemia During Carotid Endarterectomy

Previous investigations appear to indicate that an ischemic EEG is not observed during carotid cross-clamping when the stump pressure is >/=60 mm Hg. In this report of 124 carotid endarterectomies (CEA) performed with selective shunting based on computerized EEG (CEEG), we compared the CEEG and this previously established critical stump pressure level of 60 mm Hg as methods of detecting cerebral ischemia during carotid clamping. A significant association between stump pressure and CEEG findings during clamping existed (p <0.05). Only 1 of 44 patients with a stump pressure >/=60 mm Hg received a shunt based on CEEG signs of cerebral ischemia. However, 62 of the remaining 80 patients did not receive a shunt and awoke neurologically intact despite a stump pressure <60 mm Hg. A highly significant association between the postoperative neurologic exam and the CEEG findings during carotid clamping was demonstrated (p <0.001). In contrast, for stump pressure, a correlation with the neurologic exam was not found. Compared to CEEG, these results appear to indicate that a critical stump pressure of 60 mm Hg is a sensitive but not specific indicator for the placement of a shunt selectively during CEA. The combined use of these two monitors should lead to reliable shunt selection, especially when stump pressure is <60 mm Hg.

Elective carotid resection for squamous cell carcinoma of the head and neck

Patients with squamous cell carcinoma adherent to the carotid artery have a very poor prognosis, but some can be salvaged by aggressive surgical resection. Preoperative four vessel arteriography with intracranial views is mandatory to detect coexisting arteriosclerotic disease which may limit collateral perfusion of the ipsilateral cerebral hemisphere. Matas-type occlusive tests performed preoperatively are potentially dangerous and do not provide quantitative information that can be obtained intraoperatively by measuring internal carotid artery stump pressures. If the stump pressure is 50 mm Hg or greater, carotid reconstruction is unnecessary. A stump pressure of less than 50 mm Hg is an indication for reconstruction if the pharynx has not been entered during resection. If mucosal entry will be necessary and the stump pressure is less than 50 mm Hg, resection should not be carried out because of the increased risk of graft complications. Somatosensory evoked potentials predict cerebral tolerance to temporary interruption of flow but do not necessarily predict tolerance to permanent interruption of flow. Autogenous vein is the graft material of choice for reconstruction. In those patients not reconstructed, low-dose heparinization started before operation and continued for 10 days may lessen the likelihood of delayed stroke from embolization of a propagated thrombus in the carotid stump.

Anesthésie pour chirurgie carotidienne avec clampage sous contrôle de la pression résiduelle carotidienne

Carotid endarterectomy with clamping is performed in 50 patients. Internal carotid artery stump pressure is measured in all cases after clamping at the beginning of the operation. In 35 patients, an increase of systolic pressure is observed which allows a stump pressure more than 70 mmHg in 29 patients. In 15 patients, systolic pressure decreases and a stump pressure more thant 70 mmHg is observed in two patients. When the stump pressure is more thant 70 mmHg, the clamping is maintained. When the stump pressure is low, the clamping is stopped. A perfusion of Metaraminol increases systolic pressure in all cases : stump pressure is measured again after a second clamping. In 17 cases out of 19, stump pressure increases more than 70 mmHg and the clamping is maintained. In the two cases with a low stump pressure, a shunt is used during intervention.

Stump pressure: an unreliable guide for shunting during carotid endarterectomy.

A correlative analysis was made between the neurological status of the awake patient and the internal carotid artery stump pressure in 125 consecutive patients undergoing carotid endarterectomy. There was no mortality in this series. Twenty-four patients lost consciousness immediately after carotid cross-clamping, even though stump pressures were above 50 mm Hg in more than one third of the cases. The majority (80.8%) of the patients tolerated cross-clamping (stump pressures were between 20 and 90 mm Hg). This study demonstrated the variability of cerebral tolerance relative to absolute stump pressure guidelines, such as 25 or 50 mm Hg; reliance on these values to determine the need for intraoperative shunting could lead to stroke at operation. Our experience also showed that assessment of the awake but tranquil patient continues to be the safest and most reliable guide to selective shunting during carotid endarterectomy.

Cardiac Function and Hypercarbia

• In 12 patients with heart disease, hypercarbia was induced for carotid endarterectomy. Anesthesia was maintained with nitrous oxide in oxygen and methoxyflurane. In addition to intra-arterial measurements of blood pressure, cardiac output, systolic time intervals (STI), and pressure time indices (PTI) were determined in order to assess cardiovascular responses in these patients. Internal carotid stump blood pressure was measured in five patients before and after induction of hypercarbia. Mild elevation of the Paco2level affected systolic time intervals but not heart rate and blood pressure. When Paco2levels reached 56 to 65 torr, systolic but not diastolic blood pressure rose significantly, heart rate and cardiac output increased, while the shortening in the preejection period (PEP), left ventricular ejection lime (LVET), and the decrease in the PEP/LVET ratio signified increased mechanical cardiac activity. Hypercarbia caused intense sympathetic stimulation as demonstrated by twofold to threefold increases in plasma catecholamine levels. Stump blood pressure was elevated. Cardiac oxygen demand was significantly increased, while coronary filling time was shortened, as indicated by the increase in the tension time index and shortening in the diastolic time. This signified a relative myocardial underperfusion. Thus, while hypercarbia to levels of 66 to 70 torr increased internal carotid artery stump pressure, it also caused increased cardiac mechanical activity and concomitant unfavorable balance between myocardial oxygen consumption and supply. The measurement of STI and the computation of PTI provided early detection of alterations in cardiac function. (Arch Surg113:1196-1200, 1978)

Complications of carotid endarterectomy and their prevention.

AbstractMortality and morbidity associated with carotid endarterectomy may be minimized by proper selection of patients and proper operative and postoperative management. Complications include cardiac and airway problems related to anesthesia, infection, hematoma, nerve pareses, parotitis, arterial disruption, false aneurysms, and carotid‐cavernous fistula. The most serious complication is the occurrence of neurologic deficits as a result of cerebral emboli or ischemia. Emboli are due to excessive manipulation of the artery, while ischemia results from hypotension, intracerebral thrombosis, or inadequate cerebral protection. Adequacy of collateral blood flow during carotid clamping is determined by temporary occlusion under local anesthesia, measurement of internal carotid artery stump pressure, or EEG monitoring. The most reliable method of cerebral protection is a temporary inlying shunt. Selective shunting is used if the patient is intolerant of temporary clamping, if stump pressure is below 55 mm Hg, or if EEG changes occur. For maximum safety, the author suggests routine shunting and general anesthesia. Operative mortality for patients experiencing transient ischemic attacks should be less than 1% and operation‐related neurologic deficits no more than 2%. Meticulous attention to technical details is obligatory. Hypotension should be avoided during and after operation to avert thrombosis, and excessive hypertension postoperatively must be treated promptly to avoid cerebral hemorrhage and edema. Operation is contraindicated on patients with acute profound and progressing strokes.

Cardiac function and hypercarbia.

In 12 patients with heart disease, hypercarbia was induced for carotid endarterectomy. Anesthesia was maintained with nitrous oxide in oxygen and methoxyflurane. In addition to intra-arterial measurements of blood pressure, cardiac output, systolic time intervals (STI), and pressure time indices (PTI) were determined in order to assess cardiovascular responses in these patients. Internal carotid stump blood pressure was measured in five patients before and after induction of hypercarbia. Mild elevation of the Paco2 level affected systolic time intervals but not heart rate and blood pressure. When Paco2 levels reached 56 to 65 torr, systolic but not diastolic blood pressure rose significantly, heart rate and cardiac output increased, while the shortening in the preejection period (PEP), left ventricular ejection time (LVET), and the decrease in the PEP/LVET ratio signified increased mechanical cardiac activity. Hypercarbia caused intense sympathetic stimulation as demonstrated by twofold to threefold increases in plasma catecholamine levels. Stump blood pressure was elevated. Cardiac oxygen demand was significantly increased, while coronary filling time was shortened, as indicated by the increase in the tension time index and shortening in the diastolic time. This signified a relative myocardial underperfusion. Thus, while hypercarbia to levels of 66 to 70 torr increased internal carotid artery stump pressure, it also caused increased cardiac mechanical activity and concomitant unfavorable balance between myocardial oxygen consumption and supply. The measurement of STI and the computation of PTI provided early detection of alterations in cardiac function.

Internal carotid artery stump pressure and cerebral blood flow during carotid endarterectomy: modification by halothane, enflurane, and innovar.

Carotid endarterectomy requires temporary surgical occlusion of the involved carotid artery. During occlusion, the minimally acceptable (critical) internal carotid artery stump pressure is reported to be 50 torr, whereas for regional cerebral blood flow (rCBF), a critical range is reported to be 18-24 ml/100 g/min. During 90 carotid endarterectomies, rCBF and stump pressure were measured and the EEG continuously monitored. A positive correlation between rCBF and stump pressure (i.e., when both were either above or below their respective critical values) was observed in only 58 per cent of the cases. In 28 per cent stump pressures of less than 50 torr were observed despite rCBF's above 24 ml/100 g/min and normal EEG's. In 8 per cent stump pressures were more than 50 torr but rCBF's were less than 18 ml/100 g/min and EEG changes of ischemia were commonly observed. In the remaining 6 per cent rCBF's were marginal (18-24 ml/100 g/min) while stump pressures were more than 50 torr and EEG changes were not observed. The relationship between stump pressure and rCBF was influenced by the anesthetic. In the absence of transient ischemia during occlusion (that is, rCBF greater than 18 ml/100 g/min), halothane and enflurane anesthesia were associated with significantly higher rCBF's and lower stump pressures than was neuroleptanesthesia. Pre-occlusion and post-occlusion rCBF measurements also demonstrated cerebral vasodilation by halothane and enflurane (halothane greater than enflurane) and vasoconstriction by neuroleptanesthesia. It is concluded that stump pressure is an unreliable index of CBF during carotid occlusion and that its relationship to CBF is considerably influenced by the anesthetic.

Carotid endarterectomy: Is a shunt necessary?

Seventy-seven carotid endarterectomies performed on fifty-nine patients, using induced systemic hypertension during carotid artery clamping, were reviewed. The risk of cerebral ischemia is reduced to a minimum by this technic. The measurement of the internal carotid artery stump pressure is an excellent guideline for the need of additional brain protection. An internal shunt is rarely necessary. Thromboembolic phenomena contributed to the major neurologic complications encountered(two deaths and one stroke). Extreme gentleness and careful surgical technic cannot be overemphasized.

Internal carotid artery stump pressures during regional anesthesia.

Internal carotid artery stump pressures during regional anesthesia.

Effect of induced hypertension on internal carotid artery stump pressure and rCBF during carotid surgery.

Effect of induced hypertension on internal carotid artery stump pressure and rCBF during carotid surgery.