[Current aspects of cerebral protection in carotid surgery: update]. / Aspects actuels de la protection cérébrale en chirurgie carotidienne: mise au point.

The goal of cerebral protection in carotid surgery is to reduce postoperative central neurological complications and thus reduce morbidity-mortality of carotid endarterectomy. With improving understanding of the mechanism leading to neurological complications, means of achieving cerebral protection have been developed. Preoperative evaluation of the ischemic risk is based on the neurological examination and on computed tomography and magnetic resonance imaging findings. The possibilities of arterial supply during carotid cross-clamping can be recognized with the help of arteriography, transcranial Doppler or angio-MRI. Selective or systematic use of an intraluminal shunt and preoperative heparin therapy are the main methods used for cerebral protection. The risk of early postoperative stroke can also be reduced by careful preoperative anatomic control to detect any technical failure. Discussion on the usefulness of monitoring cerebral function during the procedure is closely related to the experience of the surgical team. The only method currently accepted by all surgeons is the use of stents during carotid angioplasty to achieve cerebral protection.

Percutaneous stenting of the internal carotid artery: the European CAST I Study. Carotid Artery Stent Trial.

PURPOSE: To report the results of a multicenter safety trial of percutaneous carotid stenting performed by vascular surgeons. METHODS: Symptomatic or asymptomatic patients > or = 65 years of age with internal carotid artery (ICA) stenoses > or = 70% and < or = 2-cm long were eligible for enrollment. The procedures were performed in an operating room with the choice of anesthesia and the percutaneous access site at the discretion of the surgeon. Only Palmaz stents were used. RESULTS: From January 1, 1996 to December 31, 1997, 99 patients (74 men, mean age 70 years, range 51 to 94) were enrolled in the study. More than half (57 of 99 patients) were asymptomatic. The direct cervical approach was used predominantly (97%). Three (3%) cases were converted to surgery for inability to access the artery or deploy the stent (technical success 97%). No perioperative death or myocardial infarction was reported. Six (6%) procedural complications included 1 reversible arterial spasm, 2 dissections, 1 cervical hematoma, and 2 residual stenoses. One neurological event reversed within 7 days (1% minor stroke rate) and 4 (4%) transient ischemic attacks resolved within 24 hours. One (1%) asymptomatic early occlusion occurred 2 days postoperatively. No neurological event was observed in the 1- to 24-month follow-up (mean 13 months). Two (2%) patients died of nonprocedurally related causes. No stent compression was seen, but 1 asymptomatic occlusion and 3 asymptomatic, non-flow-limiting restenoses (2 < 40%, 1 at 60%) were found within 1 year (3% restenosis rate on an intention-to-treat basis). Patency was 98% at 1 year. CONCLUSIONS: The results of this trial support the contention that carotid stenting of short ICA lesions can be performed with a low neurological complication rate.

[Carotid endarterectomy using eversion. One year radiologic results]. / Endartériectomie carotidienne par éversion. Résultats radiologiques à un an.

A prospective study was done in 100 patients operated on for a stenosis of the carotid artery by the eversion endarterectomy method of Van Maele (section-eversion-anastomosis) between January 1994 and August 1995. Ten patients were operated on bilaterally (thus, 110 procedures). The distribution of the patients was as follows 81 males and 19 females, mean age 71 years. Clinically, 50 patients were asymptomatic, 44 stage I, 2 stage II and 4 stage III. Arteriography of these patients showed 42 stenoses greater than or equal to 90%, 56 stenoses between 70 and 90% and 12 ulcerated plaques (according to the ESCT measurement standards). Concerning the supra-aortic vessels, 24 lesions of the vertebral-subclavian branches and 21 lesions of the intra-cerebral vessels were observed. Five endarterectomies out of the 110 (5.4%) could not be performed by this eversion method because of the immediate poor technical result before angiography. At the end of the procedure digital angiography was performed for all the patients who underwent an eversion endarterectomy (105 cases). Six images of the internal carotid artery presenting stenoses less than 30% were observed at the level of the implantation site. Two narrow stenoses of the distal part of the endarterectomy made the interposition of a PTFE graft necessary in 20% of the cases, a secondary procedure was necessary after the peri-operative angiography 2 implantations of PTFE in the internal carotid artery, 8 additional endarterectomies of the external carotid artery, 11 infiltrations with Papaverine. The immediate post-operative results were 1 death after hemiplegia, 1 hemiplegia with sequelae (mortality/morbidity approximately 2%, i.e. 2/103 eversions), 3 regressive hemipareses. Angiographic follow-ups after 1 year were performed on 100 out of 110 operated carotid arteries. With regard to the internal carotid artery, 4 patients showed a stenosis less than 30%, 1 patient a 50% stenosis, 1 patient a pre-occlusive stenosis making an operation with the interposition of a PTFE graft necessary (restenosis rate after one year 2%). All the patients followed after one year remained asymptomatic. Eversion endarterectomy is possible for the majority of the atheromatous stenoses of the carotid artery (5.4% were not possible for technical reasons). We find this method not appropriate when a shunt must be placed. Immediate results are comparable to those of classical surgical endarterectomy with or without patching. The restenosis rate at 1 year in our series is 2%. This technique provides an excellent anatomic result by peri-operative angiography and can especially be adapted to stenoses with excess of length of the carotid artery.

Experience with a lead fixation/suture sleeve.

Current anchoring systems on pacemaker leads are crude in comparison to the lead technology. Poor anchoring technique may cause damage to the lead or early displacement from incorrect suture tension. We describe experience with a locking anchoring sleeve that applies a constant gripping force to the lead body. This can be locked and unlocked to allow optimal positioning after fixation of the sleeve to underlying tissues. The sleeve was fitted to a 55D polyurethane lead (Medtronic 4024, 7 Fr, bipolar, steroid eluting) implanted in the ventricular position in 22 patients at four European centers. All implants were uncomplicated; data were collected on handling and ease of use. Assessments were made using a scale of 1-10 (10 = excellent, 5 = equivalent to conventional sleeve). Overall ease of use compared to conventional sleeve was 7.79 +/- 0.62 (mean +/- SD). Mean scoring of flexibility of the lead at the transition points was 7.92 +/- 0.72; ability to lock/unlock the sleeve scored 6.28 +/- 1.78. Ease of suturing around the sleeve scored 8.07 +/- 0.77, and ability to slide the sleeve along the lead body scored 6.48 +/- 1.99. Chest X rays at 6 weeks showed no change in lead position with respect to postimplant films, and all leads showed a straight path on either side of the sleeve with no evidence of conductor distortion. Follow-up to 3 years has been without problem. All leads remain intact and in place, with stable thresholds and no evidence of erosion. There have been no complaints of patient discomfort. We conclude that this device is safe and effective and offers a significant advance in lead fixation.

Morphologic assessment of abdominal aortic aneurysms by spiral computed tomographic scanning.

PURPOSE: The aim of this study was to seek a relationship between the morphologic features of abdominal aortic aneurysms and the feasibility of endoaortic grafting. METHODS: Between June 1995 and January 1996, 86 patients were prospectively studied with contrast-enhanced spiral computed tomographic scans, which provided 35 parameters concerning the aorta and iliac arteries. Four groups were established according to the diameter of abdominal aortic aneurysms: group A, 40 to 49 mm, 36 patients; group B, 50 to 59 mm, 26 patients; group C, 60 to 69 mm, 10 patients; and group D, greater than 70 mm, 14 patients. RESULTS: There was a correlation between the diameter and length of the aneurysm (p < 0.0001) and between aneurysm diameter and length of the proximal neck (p < 0.001). Presence of a proximal neck or a distal neck was more frequent in groups A and B than in groups C and D (p < 0.01). The feasibility of endovascular grafting was estimated at between 50% and 61.6% and was higher in groups A and B than in groups C and D (p < 0.01). CONCLUSIONS: This study has shown an inverse relationship between the diameter of the aneurysm and the length of the aortic neck (correlation coefficient, -0.3640, p < 0.001). The diameter of an aneurysm was the most useful of the 31 parameters measured in predicting the feasibility of endoaortic grafting, estimated at 71% for aneurysms less than 60 mm in diameter and 37.5% for aneurysms greater than 60 mm in diameter (p < 0.01).

[Endovascular treatment of abdominal aorta aneurysms using the Stentor device. Preliminary experience]. / Trattamento endovascolare degli aneurismi dell'aorta addominale con il dispositivo Stentor. Esperienza preliminare.

PURPOSE: The aim of this report is to describe our experience with the Stentor device for endovascular treatment of the abdominal aortic infrarenal aneurysms also extending to the bifurcation and the common iliac arteries. Stentor is a thermal memory (Nitinol) self-expanding graft, covered by an external 0.1 mm Dacron material. METHODS: Between December 1994 and July 1995 endoluminal repair of infrarenal aneurysmal disease was undertaken in 6 patients at high surgical risk. The lesions include 2 infrarenal abdominal aorto-aortic aneurysms, 2 infrarenal abdominal aortic aneurysms extended to the common iliac arteries and 2 false aortic aneurysms in patients with previous aorto-bifemoral graft. Straight grafts were implanted in 4 patients and bifurcated in 2. Repair was done in the operating room using general anesthesia. The endograft was placed through remote arteriotomies and advanced under fluoroscopic guidance to his predetermined site. Three-dimensionally reconstructed spiral CT scan and arteriography were performed before the procedure for a preoperative accurate measurement for endograft preprocedural adaptation in length and diameter. RESULTS: All endografts were successfully deployed. Intraoperative arteriography at the end of the procedure revealed a distal "leak" into an aneurysmal common iliac artery, due to diameter mismatch, in a bifurcated device. There was no instance of embolism or graft migration. No patient required conversion to an open operation. There were no instances of embolism or graft migration. No patient required conversion to an open operation. There were no coagulative disorders. Minor complications were: groin haematoma (1), fever (1), intestinal paralysis (1), pelvic pain (1). Follow-up with spiral CT-scan and echo color-Doppler confirmed normal blood flow through the graft in 5 patients and persistence of distal leak in 1 patient. CONCLUSIONS: These preliminary results demonstrate the accuracy of implantation and device's adaptability to the particular anatomy of the aneurysmal aorta and iliac arteries. Proximal fixation to the aortic wall, secure seal at the proximal and distal fixation point present the critical aspects of this new surgical technique. More detailed preoperative measurements of aneurysmal disease are required rather than for traditional surgery. Presently we prefer to treat the no operable patients with this endovascular technique in relation with shortness of the follow-up.

Aneurysms of anomalous splenomesenteric trunk: clinical features and surgical management in two cases.

Aneurysms of the splenic artery that anomalously arise from a splenomesenteric trunk are a rarity. Aneurysmal disease of visceral arteries is found in only 0.2% of the general population. The celiac trunk and superior mesenteric artery (SMA) are involved in less than 10% of all visceral aneurysms. Although rupture seems to occur in 20% to 22% of patients, the related mortality rate can rise as high as 100%. Anomalies of the celiac trunk and SMA, more common than previously claimed, include the splenic artery arising from the SMA, which occurs in only 1% of patients. We present two cases of young patients who had 4-cm aneurysms behind the pancreas that involved an anomalous splenic artery. The first patient required dissection of the entire splenopancreatic bloc through a transverse abdominal incision to excise the aneurysm and repair the SMA. The second patient was treated by the classic approach, through a median incision and by entering the mesenteric root. There do not seem to be reports of similar cases, except for two cases of aneurysms involving the celiomesenteric trunk. The cause of these aneurysms can be attributed to mesenchymal alterations during the embryonic formation of aortic collateral branches. A correct surgical approach to splanchnic aneurysms calls for awareness of potential vascular variations of the arteries and their collateral pathways.

In vitro testing of six inferior vena cava filters: filtering efficiency and pressure measurements.

UNLABELLED: The purpose of this study is to compare in standarddised ex vivo conditions the performances of six percutaneous vena cava filters available on the European Market. METHODS: We use a mock circulation with polyethylene beads simulating clots to objectively determine the filtering efficiency of the different devices. We measured pressure at contact points with the wall of the tube simulating vena cava, and also gradient of pressure induced by the empty and full filter. Statistical analysis of the data obtained (at least 100 measurements for each filter) showed great consistency in the response of a given filter to the different conditions of mock circulation. RESULTS: The Greenfield Filter, which served as the reference, was compared to the other models. Its filtering efficiency was acceptable as was that of the L.G. Filter. The Cardial Filter and Vascor Filter were the most efficient. The Antheor Filter and the Filcard Filter performed poorly. CONCLUSION: The mock circulation give reliable and reproducible data on the filtering efficiency for a device but ease of placement and clinical studies must be taken into account for the choice of the filter.

Interruption of the inferior vena cava using the Vascor filter: preliminary series of 51 cases.

Between February 1991 and October 1991, vena cava filters made of Vascor (Toulon, France) were inserted into 51 patients. The male:female ratio was 29:22 and mean age 74 (range 45-94) years. Diagnosis of thrombophlebitis was established by venography in 48 patients (94%) and ultrasonography in three (6%). Thrombosis was unilateral in 49 patients and bilateral in two, involved the pelvic veins in 38 (75%) and the leg veins in 13 (25%). Of the 51 patients, 17 (33%) presented pulmonary emboli and 12 (24%) had waving supracrural clots. The Vascor umbrella filter is a two-stage stainless-steel device with attachment tabs for anchoring and centering. It can be placed either percutaneously using a 7-gauge French introducer via the jugular, subclavian or brachial vein or surgically. In the present series, placement was achieved percutaneously via the jugular vein, in 49 cases (96%) and surgically in two (4%). Postoperative and follow-up examinations included coagulation tests, Doppler ultrasonography and abdominal radiography. In the immediate postoperative period, one patient developed a pneumothorax which was treated by pleural drainage and five died from cancer within the first month after placement. There were no postoperative accidents and no patient had recurrent embolism. In three patients, the filter tilted 30 degrees and in one caval thrombosis was identified. Follow-up examinations were performed in 46 patients, with a mean duration of 12 months. Ten patients have died. Caval thrombosis occurred in two patients (4%) but proximal migration of the filter and recurrence of pulmonary embolism have not been observed.

[The evolution of iliac artery surgery: vascular endoprostheses]. / Evoluzione nella chirurgia dell'arteria iliaca: le endoprotesi vascolari.

The Authors report their experience about vascular endoprostheses in iliac arterial stenoses and thromboses. Results are discussed in relation to technical difficulties and indications. The comparison between classic vascular surgery previously used, and the endovascular procedures recently adopted, leads the Authors to assert the validity of this last technique. However the need of precise indications based on radiological and angioscopic findings is stressed.

[In vitro bench tests of caval umbrella filters]. / Banc d'essai in vitro des filtres ombrelles caves.

Seven ombrelles percutaneous cava filters, now available, are tested on hydraulic testing ground. Measurements are concerned with the blocking function of filters and pressure changes induced in the cava flow and the cava track wall of the testing ground. A statistical analysis of the results (100 measurements per filter) shows homogeneous reactions of each filter when faced with different situations imposed by variations of the testing ground. Greenfield's filter, a reference, is compared with other models. This one and the L.G. filter show satisfactory filtering qualities. Two other filters, Cardial and Vascor, offer a highest filtering power. Other models give poor filtering results.

[Associated surgery of the carotid and subclavian arteries: indications and results]. / Chirurgie carotidienne et sous-clavière associée: indications et résultats.

Over a 5 year period (1988-1992), 6 patients were treated by combined carotid and subclavian artery surgery, representing 0.7% of carotid interventions practised during this period. The carotid lesion clinical stage was 0 (2 cases), 1 (2 cases) and 3 (2 cases). While for the subclavian artery 4 patients were asymptomatic and 2 had vertebrobasilar syndromes, one associated with ischemia of upper limb. Only one patient was globally asymptomatic but the diagnosis was a prethrombotic carotid restenosis. Radiographs showed that the atheromatous lesion of the cervical trunks was equivalent to 2.83 stenoses per patient. The decision to use the combined interventions was based on either the clinical condition (combined carotid and vertebrobasilar symptomatology) or hemodynamic data (improvement in subclavian flow during carotid surgery). This hemodynamic component could be determined by transcranial Doppler. Operation consisted always of initial subclavian revascularization (1 reimplantation, 5 bypasses), followed by carotid surgery (2 grafts, 4 endarterectomies). The postoperative course was uneventful in 5 patients, the 6th patient requiring recovery surgery for early carotid thrombosis without worsening of the neurologic state. Mean follow up was 9 months (range 1 to 27 months). Combining these two interventions in this small series did not appear to increase carotid surgery complication. Initial revascularization of the subclavian artery in the patient with multiple trunk lesions corrected the posterior hemodynamic supply to the circle of Willis.

The role of omentopexy in the prevention of femoral anastomotic aneurysm.

In our experience the incidence of anastomotic aneurysms (AA) after prosthetic bypass varied from 0.3 to 0.7% depending on location; it was 5 times higher at aortobifemoral anastomoses (77/3146; 2.44%) than aortic anastomosis (8/2173; 0.37%) (p less than 0.005). In the inguinal region the incidence of femoral AA (FAA) is the same as elsewhere when the prosthesis is placed in front of the inguinal ligament (axillo-femoral anastomoses, 1/200; 0.5%; femoro-femoral anastomoses 1/270; 0.37%). However when the prosthesis is placed behind the ligament, the incidence of FAA rises to 2.44% (77/3746). In our opinion, this difference is due to adherence between the prosthesis and the ligament during hip movement. When the hip is in extension, tension is placed on the prosthesis and the adjacent arterial junction causing the wall of the artery to tear. The sutures almost always remain intact. In an effort to avoid this problem, we have developed a technique that consists of enlarging the passage of the prosthesis by partial section of the inguinal ligament and then wrapping the prosthesis with a free non pedunculated segment of omentum from above the femoral anastomosis down to the healthy segment of the femoral artery which, being elastic, can stretch. The omentum acts as sheath that reinforces the anastomosis. To evaluate this technique we assessed our patients operated upon for aortobifemoral (or aortofemoroiliac) bypass into two groups. Group A included 115 patients operated on by the same surgeon using the new technique (October 1981 and December 1984). There were 111 men and 4 women (mean age: 59.7 years). Mean follow-up was 7.36 years.(ABSTRACT TRUNCATED AT 250 WORDS)

[Vascular endoprosthesis. A new indication in the surgery of the iliac artery]. / Les endoprothèses vasculaires. Une nouvelle indication dans la chirurgie de l'artère iliaque.

We have used endoprosthesis (Palmaz Schatz) after balloon angioplasty of iliac arterial stenoses or thromboses, in order to increase the immediate patency and to prevent the recurrence of stenosis. Our series gathers 24 patients operated with endovascular procedures over a period of 2 years: 22 men, 2 women--extreme ages 42 to 78 years, average age 63.5 years--Clinical stage: 22 at stage I, 1 at stage III, 1 at stage IV. Arteriographic findings: 8 primary iliac lesions (6 stenoses and 2 thromboses), 11 external iliac lesions (stenoses). All these lesions were atheromatous. One of them had recurred after angioplasty. Usual technique: balloon angioplasty of the stenosis, assessment on a fluoroscopic screen and angioscopy of the result, decision to insert the Palmaz Stent if defects are seen on the image. Repatency of impassable lesions with a YAG laser was carried out in 2 cases. The indication of an endoprosthesis was established on the basis of the radiological image in 17 cases, of the angioscopic image in 4 and systematically in 10 cases of recurrence of stenosis, iliac thrombosis or associated surgery. Associated surgery: 2 femoropopiteal bypass grafts, 3 femorofemoral bypass grafts, 1 deep plasty, 1 superficial femoral recanalization with laser, 1 lymbar sympathectomy. Postoperative results: 1 death due to MI (78-year-old diabetic woman), 1 thrombosis treated with femorofemoral bypass. Middle-term results: after 6 to 24 months, average time lapse 13 months. The comparison of the ankle pressure indices and of the pre- and postoperative sonographic findings shows an indisputable hemodynamic improvement.

Stroke prevention during carotid surgery in high risk patients (value of transcranial Doppler and local anesthesia).

In a series of 114 cases, carotid surgery was performed under local anesthesia by cervical block in order to assess cerebral status. Preoperative transcranial Doppler was used to select high risk patients for shunting. Intraoperatively brain function was checked by carotid arterial blood pressure monitoring and transcranial Doppler. No stroke occurred during the procedure. Postoperatively two deaths (1.8%) occurred, one due to intracerebral hemorrhage and one to a late myocardial infarct. The predictive value of both transcranial Doppler and stump pressure monitoring for shunting was 97% respectively. In combination, the two methods provided 100% protection. During the same period, 1406 patients underwent carotid surgery under general anesthesia. Carotid surgery stroke can be prevented either by using transcranial Doppler together with carotid stump pressure monitoring when the procedure is performed under general anesthesia or by operating under local anesthesia.

Etiology of prosthetic anastomotic false aneurysms: pathologic and structural evaluation in 26 cases.

To determine the etiology of anastomotic false aneurysms (AFAs), 26 textile graft specimens, removed because of AFA, were studied morphologically, histologically and by scanning electron microscopy. No cases of suture-related failures leading to AFA were found. Nine cases of frayed grafts were documented but were not the cause of AFA formation. In three cases, chemical degradation of the fibres, which may have been secondary to lipid infiltration, may have contributed to AFA formation. There were no cases of overt clinical infection, but the presence of bacteria was documented by scanning electron microscopy in 20 cases. The role of bacteria is not well defined, but they may be a factor in host arterial-wall degeneration as a cause for AFA formation.

[Early angiographic assessment of coronary revascularizations using the internal mammary artery. Apropos of a consecutive and prospective series of 180 bypass grafts]. / Contrôle angiographique précoce des revascularisations coronaires par l'artère mammaire interne. A propos d'une série consécutive et prospective de 180 pontages.

This report describes a consecutive and prospective series of 136 patients, who underwent coronary bypass using the internal mammary arteries. Coronary angiography was routinely performed on all patients 8 days after surgery. A total of 137 operations (1 reoperation) were performed on 180 coronary arteries using 132 left internal mammary arteries and 25 right internal mammary arteries. Direct bypass was performed 133 times (73.8%), sequential bypass 23 times (25.5%) and free graft once. Bypass involved 1 coronary artery 89 times (65.4%), 2 coronary arteries 46 times (33.8%) and 3 coronary arteries in 1 case. The overall early success rate of internal mammary bypass in this series was 94.8% including 2 bypasses which were patent but non-functional. Of the 23 sequential bypasses, only 1 anastomosis out of 46 was not patent for a success rate of 97.3%. These good results are attributed to the large diameter of the mammary artery. Early postsurgical imaging is valuable for several reasons. It allows detection of surgical errors and improvement of the procedure. It enables distinction between residual primary surgical stenosis and secondary stenosis or genuine restenosis. It allows analysis of perioperative complications allows. No correlations between myocardial infarction and bypass obstruction were found. Finally, it permits endoluminal therapies such as thrombolysis (1 case in this series) and dilatation (2 cases). In conclusion, although we do not perform angiography routinely, our policy is to perform imaging in all cases of postoperative complications and after certain procedures such as sequential bypass.

[Revascularization of the distal portion of the deep femoral artery. Indications and results]. / Revascularisation de l'artère fémorale profonde distale. Indications et résultats.

Most of the times, the distal part of the deep femoral artery is not affected by atheromatous disease. It constitutes an acceptable alternative, whenever the femoral bifurcation is not usable for bypass. This artery is readily approached directly, at a point removed from Scarpa's fascia. We used this technique on 60 patients. Indications included: multiple reoperations (45 cases, 75%), infection of Scarpa's fascia (2 cases, 3%), calcified or thrombosed femoral bifurcation (13 cases, 22%). Lim salvage for decubital pain, grade-IV or acute ischemic disease involved 49 cases (82%). After a mean 28.5 month follow-up period, arterial permeability was 74% and 53% after one year and 5 years, respectively. These results are compared with literature data. Long-term permeability is related to two factors: proximal bypass implantation site and the state of the popliteal reentry and arterial network of the leg. Utilization of the distal segment of the deep femoral artery via an elective approach is interesting of the deep femoral artery via an elective approach is interesting and sensible, whenever the femoral bifurcation is unusable owing to progressive atheromatous disease, repeated surgery or infection.

Pre- and intraoperative transcranial Doppler: prediction and surveillance of tolerance to carotid clamping.

We report 91 patients (mean age 70 years) operated upon, prospectively for a total of 100 carotid revascularizations (nine bilateral). Eighty-five of these patients had pre-, intra-, and postoperative transcranial Doppler investigations. Preoperatively, these 85 patients (92 procedures) were classified into two groups based on the results of their Doppler examinations: Group A (65 patients, 72 procedures), those who did not require an intraoperative indwelling shunt and Group B (20 patients, 20 procedures), those who did. The shunt was inserted only when the mean stump (back) pressure was less than 50 mmHg after cross-clamping. Group A all had satisfactory collaterality with a functional anterior and one or two posterior communicating arteries. Group B had no communicating arteries (anterior or posterior) identified by transcranial Doppler. In 17 of 20 patients in this group, the stump pressure was less than 50 mmHg and a shunt was placed. The overall prediction based on Doppler examination of whether or not patients would need a shunt during operation for the two groups A and B (i.e., 92 procedures) was correct in 95.6% (88/92) of cases. Moreover, six hemodynamically significant stenoses (four in the cavernous portion, two in the middle cerebral artery) were disclosed. Sensitivity and specificity of transcranial Doppler as correlated with arteriographic findings were 70 and 90%. Preoperative transcranial Doppler can measure the velocities of the principal cerebral arteries and the collateral capacity of the circle of Willis, and can forecast tolerance to carotid cross-clamping. Intraoperatively, the velocity of flow in the middle carotid artery was correlated with stump pressure, which allowed for surveillance of the shunt.