Plasma endothelin-1 level at the onset of ischemic ventricular fibrillation predicts resuscitation outcome.
BACKGROUND
Endogenous vasopressors, including endothelin-1 (ET-1), have been shown to be elevated in patients following resuscitation from out-of-hospital cardiac arrest and are likely a physiologic response to global ischaemia. The importance of ET-1 in the setting of arrest and resuscitation has not been established. Prior work has demonstrated that ET-1 increases significantly after coronary occlusion. The purpose of this study was to assess changes in ET-1 following induction of ischaemia and VF.


METHODS
VF was induced in 30 anesthetized and instrumented swine by balloon occlusion of the LAD. Blood was collected from the right atrium at baseline and at 5 min intervals following LAD occlusion until VF occurred. After 7 min of VF, resuscitation was attempted in accordance with guidelines. ET-1 and matrix metalloproteinase-9 (MMP-9), a measure of infarct size, were measured using ELISA.


RESULTS
ET-1 and MMP-9 levels increased significantly from baseline within 20 min of occlusion of the LAD. Animals that could not be resuscitated had a higher ET-1 (p=0.031) at VF onset but similar ischaemia time (time to VF) and MMP-9, reflecting infarct size. An ET-1 level >4 pg/ml had a likelihood ratio of 4 for predicting resuscitation failure.


CONCLUSIONS
Elevated levels of ET-1 during acute ischaemia predict resuscitation failure independent of the time to VF. This finding may be due to the known effect of ET-1 on coronary vascular resistance or ventricular compliance, resulting in early ischemic contracture.
Shah
Atman P
AP
Department of Medicine, Division of Cardiology, Harbor-UCLA Medical Center, Torrance, CA, United States. ashah@labiomed.org
Niemann
James T
JT
Youngquist
Scott
S
Heyming
Ted
T
Rosborough
John P
JP
D000818:Animals; D016887:Cardiopulmonary Resuscitation; D004195:Disease Models, Animal; D019332:Endothelin-1 / Q000097:blood*; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000097:blood; D017202:Myocardial Ischemia / Q000097:blood* / Q000209:etiology*; D011237:Predictive Value of Tests; D013552:Swine; D013997:Time Factors; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000097:blood* / Q000150:complications / Q000628:therapy*
D019332:Endothelin-1; D020780:Matrix Metalloproteinase 9