Catheter-based transcoronary myocardial hypothermia attenuates arrhythmia and myocardial necrosis in pigs with acute myocardial infarction.
OBJECTIVE
This study evaluated the efficacy of catheter-based transcoronary myocardial hypothermia (CTMH) in pigs with acute myocardial ischemia.


BACKGROUND
Although it has been suggested that hypothermia therapy can attenuate myocardial necrosis, few applications have been accepted for clinical use.


METHODS
This study comprises 2 substudies. In both studies, pigs underwent 60 min of coronary occlusion and 180 min of reperfusion. In study 1, after 15 min of coronary occlusion with an over-the-wire-type balloon (OTWB), pigs in the hypothermia group (H) (n = 13) were directly infused with 4 degrees C saline into the coronary artery through the OTWB wire lumen (2.5 ml/min) for 60 min. Pigs in the normothermia group (N) (n = 15) received the same amount of 36.5 degrees C saline. In study 2, pigs in the hypothermia-reperfusion group (HR) (n = 5) were infused with 4 degrees C saline through the infusion catheter (8 ml/min) for 30 min with a later start (60 min after coronary occlusion), whereas simple reperfusion was used for the reperfusion group (R) (n = 6).


RESULTS
Catheter-based transcoronary myocardial hypothermia was successful in both studies. In study 1, CTMH significantly decreased ventricular arrhythmia and the ratio of necrosis to ischemic risk area (H: 9 +/- 2%; N: 36 +/- 4%; p < 0.0001) with a significant reduction of enzyme leaks. In study 2, CTMH tended to reduce the ratio of necrosis (HR: 33 +/- 2%; R: 45 +/- 5%; p = 0.08). In both studies, CTMH significantly suppressed the increase of 8-iso-prostaglandin F(2alpha) while preserving the coronary flow reserve.


CONCLUSIONS
Catheter-based transcoronary myocardial hypothermia reduced myocardial necrosis while preserving coronary flow reserve, due, in part, to attenuation of oxidative stress.
Otake
Hiromasa
H
Division of Cardiovascular and Respiratory Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
Shite
Junya
J
Paredes
Oscar Luis
OL
Shinke
Toshiro
T
Yoshikawa
Ryohei
R
Tanino
Yusuke
Y
Watanabe
Satoshi
S
Ozawa
Toru
T
Matsumoto
Daisuke
D
Ogasawara
Daisuke
D
Yokoyama
Mitsuhiro
M
D000704:Analysis of Variance; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000517:prevention & control* / Q000628:therapy; D002404:Catheterization; D003326:Coronary Circulation / Q000502:physiology; D004195:Disease Models, Animal; D005260:Female; D007036:Hypothermia, Induced / Q000295:instrumentation / Q000379:methods*; D008297:Male; D009203:Myocardial Infarction / Q000473:pathology* / Q000628:therapy*; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control* / Q000628:therapy; D009336:Necrosis / Q000473:pathology / Q000517:prevention & control; D011336:Probability; D012680:Sensitivity and Specificity; D013552:Swine