ORIGINAL ARTICLES   

Giornale Italiano di Chirurgia Vascolare 2001 March;8(1):1-11

Copyright © 2002 EDIZIONI MINERVA MEDICA

language: English, Italian

Role of transcranial Doppler in pre- and intraoperative risk evaluation of cerebral ischemia during clamping

Martinelli O., Trenti E., Stumpo R., Gossetti B., Benedetti-Valentini F.

From the 2nd Chair of Vascular Surgery University “La Sapienza”, Rome, Italy

Background. Intraoperative neu­ro­log­i­cal def­i­cits dur­ing the ­course of carot­id sur­gery are main­ly ­linked to micro­em­bol­ic ­events, but ­they can ­also be ­caused by cere­bral hypo­per­fu­sion as a con­se­quence of carot­id clamp­ing. Transcranial Doppler (TCD) ultra­so­nog­ra­phy is cur­rent­ly ­used to eval­u­ate the ­risk of cere­bral ische­mia ­caused by carot­id clamp­ing.
Methods. A ­total of 508 ­patients under­went carot­id sur­gery ­using loco­re­gion­al anes­the­sia ­between January 1991 and December 1998. They ­were stud­ied ­using TCD ­both pre­op­er­a­tive­ly and dur­ing the ­course of sur­gery. Preoperatively TCD was ­used to ­assess the cere­bral vas­o­mo­tor ­response, the effi­cien­cy of com­mu­ni­cat­ing arter­ies, the find­ings of the com­pres­sion ­test on the com­mon carot­id ­artery at the ­base of the ­neck. TCD was ­used intra­op­er­a­tive­ly to eval­u­ate the chang­es ­induced on ­flow of the medi­um cere­bral ­artery, homo­lat­er­al to the ­test carot­id clamp­ing.
Results. The ­results of TCD ­were cor­re­lat­ed ­with the num­ber of ­shunts ­used and intra­op­er­a­tive neu­ro­log­i­cal def­i­cits ­observed. This cor­re­la­tion high­light­ed ­that: 1) the pres­ence of an acti­vat­ed intra­cra­ni­al col­lat­er­al cir­cu­la­tion or one ­able to be acti­vat­ed and the vas­o­mo­tor ­response are direct­ly cor­re­lat­ed ­with tol­er­ance of carot­id clamp­ing in respec­tive­ly 52 and 70% of cas­es; 2) the pre­op­er­a­tive carot­id com­pres­sion ­test ­showed a sen­si­tiv­ity of 63% and 98% spec­i­fic­ity; 3) if the ­mean veloc­ity of the medi­um cere­bral ­artery dur­ing ­test clamp­ing ­fell ­more ­than 30% ­below ­basal val­ues it was an ­index of a fail­ure to tol­er­ate clamp­ing in 93% of cas­es.
Conclusions. These ­results empha­sise ­that TCD is a reli­able meth­od for eval­u­at­ing the ­risk of cere­bral ische­mia con­se­quent to carot­id clamp­ing pre­op­er­a­tive­ly and, ­above all, dur­ing sur­gery.