Cardiac Arrest in Pigs With 48 hours of Post‐Resuscitation Care Induced by 2 Methods of Myocardial Infarction: A Methodological Description

Abstract

Background Systematic reviews have disclosed a lack of clinically relevant cardiac arrest animal models. The aim of this study was to develop a cardiac arrest model in pigs encompassing relevant cardiac arrest characteristics and clinically relevant post‐resuscitation care. Methods and Results We used 2 methods of myocardial infarction in conjunction with cardiac arrest. One group (n=7) had a continuous coronary occlusion, while another group (n=11) underwent balloon‐deflation during arrest and resuscitation with re‐inflation after return of spontaneous circulation. A sham group was included (n=6). All groups underwent 48 hours of intensive care including 24 hours of targeted temperature management. Pigs underwent invasive hemodynamic monitoring. Left ventricular function was assessed by pressure‐volume measurements. The proportion of pigs with return of spontaneous circulation was 43% in the continuous infarction group and 64% in the deflation‐reinflation group. In the continuous infarction group 29% survived the entire protocol while 55% survived in the deflation‐reinflation group. Both cardiac arrest groups needed vasopressor and inotropic support and pressure‐volume measurements showed cardiac dysfunction. During rewarming, systemic vascular resistance decreased in both cardiac arrest groups. Median [25%;75%] troponin‐I 48 hours after return of spontaneous circulation, was 88 973 ng/L [53 124;99 740] in the continuous infarction group, 19 661 ng/L [10 871;23 209] in the deflation‐reinflation group, and 1973 ng/L [1117;1995] in the sham group. Conclusions This article describes a cardiac arrest pig model with myocardial infarction, targeted temperature management, and clinically relevant post‐cardiac arrest care. We demonstrate 2 methods of inducing myocardial ischemia with cardiac arrest resulting in post‐cardiac arrest organ injury including cardiac dysfunction and cerebral injury.

Cerebral monitoring in a pig model of cardiac arrest with 48 h of intensive care

“…As previously reported, 17 pigs were included in this study and divided in the two groups (11 cardiac arrest and 6 sham pigs) [ 2 ]. Seven pigs in the cardiac arrest group achieved ROSC (baseline data from all pigs are included in analyses).…”

“…This manuscript describes cerebral outcome data from a previously published experiment. Detailed methodological descriptions are described therein [ 2 ]. Animals were assigned to the groups at the discretion of the primary investigator in a non-randomized order.…”

“…Induction of myocardial infarction, cardiac arrest, resuscitative efforts, and the post-cardiac arrest intensive care protocol for this experiment have been described in detail previously [ 2 ]. The earlier report included two different methods of myocardial infarction.…”

“…Data in figures are presented as median with corresponding 25% and 75% quartiles. ICP, MAP, PaO 2 , and NSE from the same experiments have previously been reported [ 2 ], but to sufficiently interpret the dataset of this manuscript these variables have been included. Statistical significance was defined as a two-sided p -value < 0.05.…”

“…The number of published studies including a clinically relevant cardiac arrest animal model is limited [ 1 ]. To address this, we have developed a cardiac arrest pig model with myocardial infarction and 48 h of post-resuscitation care [ 2 ]. In that model, we found significantly depressed cardiovascular function as well as signs of renal, hepatic, and pulmonary injury during the post-cardiac arrest phase.…”