Who benefits most from mild therapeutic hypothermia in coronary intervention era? A retrospective and propensity-matched study.
BACKGROUND
The aim of the present study was to investigate the impact of the time interval from collapse to return of spontaneous circulation (CPA-ROSC) in cardiac arrest patients and the types of patients who will benefit from therapeutic hypothermia.


METHODS
Four hundred witnessed adult comatose survivors of out-of-hospital cardiac arrest of cardiac etiology were enrolled in the study. The favorable neurological outcome was defined as category 1 or 2 on the five-point Pittsburgh cerebral performance scale at the time of hospital discharge. A matching process based on the propensity score was performed to equalize potential prognostic factors in the hypothermia and normothermia groups, and to formulate a balanced 1:1 matched cohort study.


RESULTS
The rate of favorable neurological outcome was higher (P < 0.05) in the hypothermia group (n = 110) than in the normothermia group in patients with CPA-ROSC of 15 to 20 minutes (64% vs. 17%), 20 to 25 minutes (70% vs. 8%), 25 to 30 minutes (50% vs. 7%), 35 to 40 minutes (27% vs. 0%) and 40 to 45 minutes (29% vs. 2%). A similar association was observed in a propensity-matched cohort, but the differences were not significant. There was no significant difference in the rate of favorable neurological outcome between the hypothermia-matched group and the normothermia-matched group. In the patients whose CPA-ROSC was greater than 15 minutes, however, the rate of favorable neurological outcome was higher in the hypothermia-matched group than in the normothermia-matched group (27% vs. 4%, P < 0.001). In multivariate analysis, the CPA-ROSC was an independent predictor of favorable neurological outcome (every 1 minute: odds ratio = 0.89, 95% confidence interval = 0.85 to 0.92, P < 0.001).


CONCLUSIONS
The CPA-ROSC is an independent predictor of neurological outcome. Therapeutic hypothermia is more beneficial in comatose survivors of cardiac arrest with CPA-ROSC greater than 15 minutes.
Kagawa
Eisuke
E
Department of Cardiology, Hiroshima City Hospital, 7-33 Moto-machi, Naka-ku, Hiroshima 730-8518, Japan. ekagawa@za2.so-net.ne.jp
Inoue
Ichiro
I
Kawagoe
Takuji
T
Ishihara
Masaharu
M
Shimatani
Yuji
Y
Kurisu
Satoshi
S
Nakama
Yasuharu
Y
Dai
Kazuoki
K
Otani
Takayuki
T
Ikenaga
Hiroki
H
Morimoto
Yoshimasa
Y
Ejiri
Kentaro
K
Oda
Nozomu
N
D000368:Aged; D000369:Aged, 80 and over; D003128:Coma / Q000628:therapy; D005260:Female; D006323:Heart Arrest / Q000628:therapy*; D006801:Humans; D007036:Hypothermia, Induced; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D057216:Propensity Score; D012372:ROC Curve; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D013997:Time Factors; D016896:Treatment Outcome