ORIGINAL ARTICLES  CARDIAC PAPERS 

The Journal of Cardiovascular Surgery 1998 October;39(5):613-7

Copyright © 2000 EDIZIONI MINERVA MEDICA

lingua: Inglese

Intracranial high-intensity transient signals after homograft or mechanical aortic valve replacement

Lievense A. M. ^{1, 2}, Bakker S. L. M. ², Dippel D. W. J. ², Taams M. A. ³, Koudstaal P. J. ², Bogers A. J. J. C. ¹

From the Departments of 1 Cardiothoracic Surgery, 2 Neurology and 3 Cardiology, University Hospital, Rotterdam, The Netherlands

Objective. Comparison of the occur­rence, inten­sity and ­rate of ­high-inten­sity tran­sient sig­nals (­HITS), meas­ured in ­both mid­dle cere­bral arter­ies by trans­cra­ni­al Doppler ultra­sound (TCD) ­after mechan­i­cal or homo­graft aor­tic ­valve implan­ta­tion.
Experimental ­design. TCD mon­i­tor­ing was per­formed by ­means of a ­pulsed Doppler ultra­sound ­with two 2 MHz ­probes, sta­bi­lized on the ­head and direct­ed at the mid­dle cere­bral ­artery.
Setting. Outdoor ­patients ­after aor­tic ­valve replace­ment in a uni­ver­sity hos­pi­tal.
Patients. The ­study ­cohort com­prised a ran­dom trans­verse sam­ple of ­patients and includ­ed 20 ­patients ­with a mechan­i­cal aor­tic ­valve and 20 ­with a homo­graft aor­tic ­valve. Comparisons ­were ­made ­with 20 admit­ted con­trol ­patients.
Interventions. No inter­ven­tions.
Measures. No sig­nif­i­cant num­ber of ­HITS ­were expect­ed in the homo­graft ­group and a lim­it­ed num­ber in the mechan­i­cal ­valve ­group.
Results. ­HITS ­were detect­ed in ­more ­patients ­after implan­ta­tion of a mechan­i­cal aor­tic ­valve pros­the­sis com­pared ­with a homo­graft aor­tic ­valve (16 ver­sus 8, p=0.02). Nevertheless, ­more ­patients ­with a homo­graft aor­tic ­valve ­showed ­HITS ­than the con­trol ­patients (8 ver­sus 1, p=0.02). The ­mean num­ber of ­HITS in the mechan­i­cal pros­the­sis ­group was high­er ­than in the homo­graft ­group (3, ­range 0-18 ver­sus 13, ­range 0-70, p<0.05). ­HITS in ­patients ­with mechan­i­cal pros­the­ses had a high­er ampli­tude ­than ­HITS in ­patients ­with homo­graft aor­tic ­valves (p<0.0001). Focal neu­ro­log­i­cal def­i­cit (FND) was diag­nosed in 9 ­patients (mechan­i­cal pros­the­sis 6 ver­sus homo­graft 3, ns).
Conclusions. ­HITS com­mon­ly ­occur ­both in ­patients ­with a mechan­i­cal aor­tic ­valve and in ­patients ­with a homo­graft aor­tic ­valve. ­HITS ­occur sig­nif­i­cant­ly ­less ­often, at a low­er ­rate and ­with a low­er inten­sity in ­patients ­with homo­graft aor­tic ­valve com­pared ­with ­patients ­with a mechan­i­cal aor­tic ­valve. Future stud­ies ­should elu­ci­date the ­nature and prog­nos­tic sig­nif­i­cance of ­HITS and ­their rela­tion­ship ­with throm­boem­bol­ic ­events.