Integrated Myocardial Management: Background and Initial Application

Abstract

This report describes the technique of integrated myocardial management, which combines the advantages of various cardioprotective strategies to compensate for their individual shortcomings. This approach coordinates the myocardial protective techniques with the continuity of the operation so that the surgical procedure is never interrupted. This method (1) provides unimpaired vision, (2) avoids unnecessary ischemia and cardioplegic overdose, (3) allows aortic clamping as soon as cardiopulmonary bypass is started, (4) permits aortic unclamping and discontinuation of bypass shortly after the technical procedure is completed, (5) minimizes the duration of ischemia and cardiopulmonary bypass, and (6) maximizes the positive attributes of the strategies available currently. The background for this myocardial management method, which combines antegrade/retrograde delivery, warm/cold blood cardioplegia, intermittent/continuous perfusion, blood/blood cardioplegia, and avoidance of cardioplegic overdose, hemodilution, and tangential aortic clamping, is discussed. The preliminary results in 1474 patients from four centers where surgeons participated in the infrastructure of this method are presented. This has led to our adoption of this approach in all adult cardiac operations.

Reperfusion Strategy after Regional Ischaemia: Simulation of Emergency Revascularization and Effects of Integrated Cardioplegia on Myocardial Resuscitation

“…12 Metabolic studies show that different myocardial regions are perfused by these two different delivery routes. 7 Our results suggest that re-establishing oxidative metabolism was delayed in group A and more rapidly restored in group B. The higher oxygen extraction levels in group B after reperfusion support this suggestion.…”

“…7 Hypothermia during emergency revascularization also protects the cells by reducing the rate and strength of processes leading to myocardial cell death and promoting electromechanical quiescence. 8 Profound hypothermia may, however, cause dysfunction of the unaffected areas.…”

Glycosylated hemoglobin levels and outcome in non-diabetic cardiac surgery patients

“…The cardioplegic solution contained 5% dextrose and additives. 21 Standard cardioplegia strategy included an induction dose of 1,000 mL at the time of the aortic cross-clamp application (5% dextrose solution 200 mL), and 500 mL (5% dextrose solution 100 mL) every 20 min thereafter until aortic cross-clamp removal. During the time period of this study, our centre's standard of care for antifibrinolytic therapy was aminocaproic acid, with aprotonin being used for high-risk (primarily redo) procedures.…”

Sudden cardiac death: Directing the scope of resuscitation towards the heart and brain

“…This can be achieved via femoral (femoral bypass) or great vessel cannulation via sternotomy. The third is prompt diagnosis and coronary revascularization utilizing a myocardial protection strategy that both limits further damage during the requisite period of aortic clamping needed for coronary grafting and restores global cardiac function (20). This is accomplished by the infusion of amino acid enhanced warm blood cardioplegia, which has been shown to recover function of the acutely ischemic or infarcted myocardium despite prolonged CPR (21; 22).…”

“…If primary coronary bypass was performed, or if a prior graft was revised, a maintenance dose of low potassium cold blood cardioplegia (4º C) was then administered through the same routes. Coronary bypass grafts were constructed and maintenance cardioplegia delivered in a sequence previously described as the "integrated method" (20). A 20-minute infusion of warm enriched blood cardioplegia was delivered followed by antegrade warm blood perfusion until adequate cardiac contractility resumed.…”