Residual dissection of the brachiocephalic arteries: significance, management, and long-term outcome.
OBJECTIVE
Residual dissection of the brachiocephalic arteries after operations for acute type A dissection is considered a benign condition that does not expose patients to late neurologic events. This retrospective study, conducted on an outpatient clinic basis between June 1995 and May 2003, had the objectives of evaluating the consequences of residual dissection of the brachiocephalic arteries, investigating the long-term outcomes of patients with this condition, and illustrating our approach to the condition.


METHODS
Forty-two of 137 patients with spontaneous aortic dissection were identified as having residual dissection of the brachiocephalic arteries. There were 30 men and 12 women, with median age of 64.8 years. Patients were followed for a median time of 3.17 years (25th-75th percentile, 1.43-4.40 years; maximum, 7.5 years). The main outcome was the occurrence of cerebral ischemic events (transient ischemic attack or stroke) or death. The functional consequences of brachiocephalic artery dissection were studied by using duplex scanning and transcranial Doppler ultrasonography.


RESULTS
Twenty-four focal neurologic complications occurred in 13 of 42 patients (incidence, 30.9%); major strokes occurred in 6 patients, and none were fatal. Minor strokes occurred in 12 patients. In all patients the damaged territory was dependent on a dissected artery. Kaplan-Meier (90-months) freedom from focal neurologic events was 55.7% (95% confidence interval, 33.7%-72.9%). Mean time of freedom from focal neurologic events was 64.5 months (95% confidence interval, 53.1-75.9 months). Positive transcranial Doppler monitoring for microembolic signals was 24.1%, and patients with clinical symptoms had higher microembolic signal counts than did those without symptoms (8.4/h vs 1.9/h, P <.001). Reduced cerebrovascular reactivity to hypercapnia, calculated by using the breath-holding index values, was associated with severely impaired brachiocephalic artery perfusion. The multivariable model for predictors of late stroke (minor and major) included the following variables: microembolic signal count (1 signal/h increase; relative risk, 1.27 [95% CI, 1.12-1.77]), breath-holding index (0.10 increase; relative risk, 0.91 [95% CI, 0.87-0.94]), and the presence of at least one carotid axis with a thrombosed false channel (relative risk, 0.82 [95% CI, 0.64-0.93]). Sixteen operations were performed in 12 patients to relieve residual dissection.


CONCLUSIONS
These results suggest an increased risk of ischemic events ipsilateral to the dissected arteries. Strict follow-up and identification of subjects at risk implies the exact knowledge of vessel anatomy and perfusion status. Ultrasonographic transcranial Doppler examination plays an important role in the clinical work-up of these patients.
Neri
Eugenio
E
Dipartimento di Chirurgia, Universitá agli Studi di Siena, Policlinico le Scotte, Viale M. Bracci, 53100 Siena, Italy. euxneri@tin.it
Sani
Guido
G
Massetti
Massimo
M
Frati
Giacomo
G
Buklas
Dimitrios
D
Tassi
Rossana
R
Giubbolini
Michele
M
Benvenuti
Antonio
A
Sassi
Carlo
C
D000368:Aged; D000784:Aortic Dissection / Q000150:complications* / Q000601:surgery*; D017545:Aortic Aneurysm, Thoracic / Q000150:complications* / Q000601:surgery*; D016122:Brachiocephalic Trunk / Q000601:surgery*; D001927:Brain Diseases / Q000453:epidemiology; D002560:Cerebrovascular Circulation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology; D012189:Retrospective Studies; D013997:Time Factors