Improved myocardial protection using continuous coronary perfusion with normothermic blood and beta-blockade with esmolol.

Abstract

Continuous coronary perfusion with warm beta-blocker-enriched blood has been suggested as an alternative to cardioplegic arrest for myocardial protection during coronary artery surgery. The purpose of the present work was 1.) to experimentally investigate this technique using an animal model, and 2.) to clinically apply this alternative myocardial protection technique and compare it to standard crystalloid cardioplegia in a controlled study. We placed 6 dogs on CPB and 6 dogs on a biventricular assist device and created "beta-blocker-induced cardiac surgical conditions" by suppressing myocardial chronotropy and inotropy with systemic infusion of the ultra-short acting beta-blocker esmolol. For the clinical study we randomized 60 coronary artery surgery patients to receive either crystalloid cardioplegia (Bretschneider HTK) or selective continuous coronary perfusion via the aortic root with warm esmolol-enriched CPB blood. In the experimental study we found that continuous coronary perfusion with warm esmolol-enriched blood avoided myocardial ischemia and minimized myocardial edema, thus completely preserving cardiac performance. Our clinical data showed the alternative technique to be superior to standard crystalloid cardioplegia in terms of both functional and structural myocardial protection. The concept of beta-blocker-induced cardiac surgical conditions is a useful alternative for myocardial protection during coronary artery surgery and may be particularly beneficial for severely compromised hearts.