Cold reperfusion before rewarming reduces neurological events after deep hypothermic circulatory arrest.
OBJECTIVE
To identify a safety threshold of deep hypothermic circulatory arrest (DHCA) duration; to determine which protection offers the best outcome and whether a 10-min period of cold perfusion (20°C) preceding rewarming can reduce neurological events (NE).


METHODS
From January 1988 to April 2009, 456 patients underwent aortic surgery using DHCA: for chronic disease in 239 and acute in 217. Cerebral protection was obtained by straight DHCA (sDHCA) in 69 cases, retrograde perfusion (RCP) in 198 and antegrade perfusion (ACP) in 189. In 247 subjects, a 10-min period of cold perfusion (20°C) preceded rewarming; in 209 rewarming was restarted without this preliminary.


RESULTS
Fifty-eight patients (13%) experienced NE. Twenty-two (5%) suffered temporary neurological dysfunction (TND) and 36 (8%) suffered stroke. DHCA duration >30 min was predictive for higher rate of NE (25.2% vs. 2.0%, P 0.001); after this value, only ACP was able to reduce incidence of NE (16.5% vs. 30.5%, P = 0.035). Cold reperfusion before rewarming significantly reduced incidence of NE (7.7% vs. 18.7%, P < 0.001) and extended the safe period to 40 min. Thirty-day mortality was 16.0%. Predictors of higher early mortality were acute aortic disease, longer DHCA, lack of ACP or prompt rewarming when DHCA >30 min and postoperative stroke.


CONCLUSIONS
sDHCA remains a safe and easy tool for cerebral protection when DHCA duration is expected to be less than 30 min. When aortic surgery requires a longer period, ACP should be instituted. Before rewarming, a 10-min period of cold perfusion significantly reduces incidence of NE.
Department of Adult Cardiac Surgery,  Prince Sultan Cardiac Centre, Riyadh,  Saudi Arabia.
Michele
M
Di Mauro
Angela L
AL
Iacò
Carlo
C
Di Lorenzo
Massimo
M
Gagliardi
Egidio
E
Varone
Hussein
H
Al Amri
Antonio M
AM
Calafiore
D000368:Aged; D000704:Analysis of Variance; D001011:Aorta / Q000601:surgery*; D050792:Circulatory Arrest, Deep Hypothermia Induced / Q000009:adverse effects / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000209:etiology* / Q000517:prevention & control; D016017:Odds Ratio; D010477:Perfusion / Q000379:methods* / Q000706:statistics & numerical data; D011183:Postoperative Complications / Q000517:prevention & control; D012189:Retrospective Studies; D017694:Rewarming / Q000379:methods*; D020521:Stroke / Q000209:etiology / Q000517:prevention & control