Determinants of Inadequate Cardioprotection in Adult Patients With Left Ventricular Dysfunction

Proper preservation of the myocardium during intraoperative ischemia is a critical predictor of satisfactory clinical outcomes. However, there can be a wide degree of diversity in myocardial damage among patients receiving the same cardioplegic solution. The efficacy of cardioplegia-induced arrest can be affected by other factors, which may become apparent in more demanding clinical scenarios, such as in patients with impaired contractility at baseline. This study aims to identify these factors and assess their impact on postoperative myocardial damage. 
 
Cardioprotection is important in patients with heart failure, as the effects of inadequate cardioprotection are particularly pronounced in this patient population. Two well-established protocols are used for cardioplegia in these cases: del Nido cardioplegia (DN) and cold blood cardioplegia (CB).  Several prospective trials have evaluated the use of the del Nido protocol, but none specifically address patients with significantly impaired contractility. Therefore, current guidelines on cardiopulmonary bypass in adult cardiac surgery recommend applying the DN protocol in low-risk cases with short aortic cross-clamp times (CCTs) to minimize surgical interruptions caused by repeated perfusion of cardioplegia. Blood cardioplegia has a longer history, and its efficacy is well documented. Many surgeons consider it the most efficient protocol, particularly in ischemic or damaged myocardium, as supported by clinical studies. 
 
The decision on whether to use DN or CB is made by the surgeon, with each case treated individually. Factors that are taken into consideration include the complexity of the procedure, the estimated duration of the CCT, the risk of fluid overload in patients with heart failure or kidney disease, the potential for allergies to lidocaine, the rationale for additional cardioplegia doses (selective graft perfusion), and the patient's blood morphology parameters. 
 
Due to the differences in protocols, it is necessary to address the entire cohort and evaluate the impact of the analyzed determinants for each cardioplegia method separately. The leading hypothesis is that patients' baseline characteristics and operative determinants may impact the efficacy of cardioprotection during surgery, but this effect may vary depending on the solution used.