ORIGINAL ARTICLES   

Giornale Italiano di Chirurgia Vascolare 1998 December;5(4):201-13

Copyright © 2000 EDIZIONI MINERVA MEDICA

language: English, Italian

Transcranial Doppler and locoregional anaesthesia in carotid surgery. A comparison of several methods to detect clamping ischaemia

Varroni A., Gizzi E., Totaro R., Mangiacotti B., Carlucci M. D., Ventura M., Spartera C.

From the Department and School of Specialisation in Vascular Surgery (Head: Prof. C. Spartera) * Neurological Clinic Department of Internal Medicine and Public Health University of L’Aquila, Italy

Background. Several tech­niques ­have ­been pro­posed for intra­op­er­a­tive cere­bral mon­i­tor­ing in carot­id endar­te­rec­to­my to iden­ti­fy the ­patients who do not tol­er­ate carot­id clamp­ing and ­require cere­bral pro­tec­tion. The aim of ­this ­study is to eval­u­ate intra­cra­ni­al col­lat­er­al cir­cu­la­tion, cor­re­late the neu­ro­log­i­cal stat­us (­gold stan­dard) ­with ­stump pres­sure meas­ure­ment, EEG mon­i­tor­ing and TCD val­ues, and deter­mine the crit­i­cal lev­els of ­cross-clamp­ing tol­er­ance for select­ing ­those ­patients who ­need a ­shunt.
Methods. In the ­last two ­years we per­formed 109 carot­id endar­te­rec­to­mies ­under loco­re­gion­al anaesthe­sia (84 ­males, 25 ­females; ­mean age: 66.4±9.4). Transcranial Doppler (TCP) mon­i­tor­ing was ­used com­bined ­with elec­tro­en­ceph­a­log­ra­phy (EEG), LRA and ­stump pres­sure meas­ure­ment for the pre­ven­tion of cere­bral ischae­mia.
Results. The per­cent­age of resid­u­al ­mean mid­dle cere­bral ­artery veloc­ity (mMCAv) dur­ing carot­id ­artery com­pres­sion was sig­nif­i­cant­ly cor­re­lat­ed ­with mMCAv at carot­id clamp­ing. Cross-clamp­ing TCD val­ues ­were sig­nif­i­cant­ly low­er in ­patients ­with intra­op­er­a­tive neu­ro­log­i­cal def­i­cits (37.2±16 vs 13.27±8 cm/sec; p<0.0001). Cross-clamp­ing val­ues ­were ­also low­er in ­patients ­with EEG abnor­mal­ities (36.39±16 vs 20.23±14 cm/sec; p<0.001). Five min­utes ­after clamp­ing ­time mMCAv ­increased sig­nif­i­cant­ly (36.3±14.6 cm/sec vs 34.7±14.7 cm/sec; p<0.001). According to neu­ro­log­i­cal stat­us, a ­shunt was insert­ed in 12 cas­es. TCD ­showed a reduc­tion of 70% in mMCAv at ­cross- clamp­ing in 10 cas­es. In ­this ­series the sen­si­tiv­ity and spec­i­fic­ity of EEG mon­i­tor­ing was 75% and 96.8%, respec­tive­ly. TCD mon­i­tor­ing ­shows a sen­si­tiv­ity and spec­i­fic­ity of 83.3% and 96.9% respec­tive­ly, ­while ­stump pres­sure ­showed a sen­si­tiv­ity of 81.8% and a spec­i­fic­ity of 87.4%.
Conclusions. EEG and TCD mon­i­tor­ing are com­ple­men­tary tech­niques. Patients ­with mMCAv reduc­tions of ≥70% at ­cross- clamp­ing ­require a ­shunt. In our opin­ion, the ver­sa­til­ity of TCD sug­gests a ­more exten­sive appli­ca­tion in the ­field of carot­id sur­gery.