Abstract 111: Ischemic Postconditioning and Vasodilator Therapy During Cardiopulmonary Resuscitation Reduces Cardiac Reperfusion Injury and Preserves Left Ventricular Systolic Function
Background: Ischemic postconditioning (IPC) protects the myocardium from injury in animals and humans. Vasodilator therapy with sodium nitroprusside (SNP) and adenosine (ADE) confers myocardial protection during acute ischemia. We hypothesize that, after prolonged untreated cardiac arrest, IPC and vasodilator therapy during the initiation of CPR decreases reperfusion injury measured by cardiac biomarkers and preserve cardiac function compared to standard CPR (SCPR).
Methods: Following 15 minutes of untreated ventricular fibrillation, 39 pigs were randomized to SCPR, SCPR+IPC, SCPR+IPC+cardioprotective vasodilator therapy (SCPR+IPC+CVT), or SCPR+CVT. IPC was delivered during the first 3 minutes of CPR with 4 cycles of 20 seconds of chest compressions followed by 20-second pauses. CVT consisted of intravenous administration of SNP (2 mg) and ADE (24 mg) during the first minute of CPR. Epinephrine was administered in both groups as a 0.5 mg bolus (∼15mcg/kg) at minute 3 and was repeated every 3 minutes until return of spontaneous circulation (ROSC). The left ventricular ejection fraction (LVEF) was calculated from transthoracic echocardiograms obtained 1 and 4 hours post-ROSC. Cardiac troponin I (cTnI) and creatine kinase MB (CKMB) were obtained on all survivors 4 hours post-ROSC. ANOVA was used for statistical comparisons.
Results: IPC, IPC+CVT, and CVT alone resulted in significantly lower CKMB/cTnI levels (ng/mL) at 4 hours compared to SCPR controls (12.8±10.3/8.5±7.3; 11±9.4/4.6±5.4; 16.8±12.9/6.4±6.4 versus 36.5±23.7/31.2±34.3, respectively, p<0.05 for all compared to SCPR). LVEF 1 and 4 hours after ROSC with IPC, IPC+CVT, and CVT alone was significantly improved compared to SCPR controls (56±14%/52±14%; 54±12%/52±14%; 57±12%/59±9% compared to 36±5%/35±11%, respectively, p<0.05 for all groups compared to SCPR). No synergy was observed between IPC and CVT. ROSC was achieved in 9/9 of controls, 10/10 for the IPC and IPC+CVT, and 9/10 in CVT alone group.
Conclusions: IPC and CVT applied at the initiation of SCPR reduce cTnI and CKMB levels at 4 hours and preserve post-ROSC LVEF.
- © 2012 by American Heart Association, Inc.