Microplegia in cardiac surgery: Systematic review and meta‐analysis

Neuroprotective Effects of a Cardioplegic Combination (Adenosine, Lidocaine, and Magnesium) in an Ischemic Stroke Model

Adenosine, lidocaine, and magnesium (ALM) are clinically available cardioplegic solutions. We examined the effects of low-dose ALM on ischemic stroke in cell and animal models. Cobalt chloride (CoCl₂)-treated SH-SY5Y cells were used as a surrogate model to mimic oxygen-glucose deprivation conditions. The cells were incubated with different dilutions of ALM authentic solution (1.0 mM adenosine, 2.0 mM lidocaine, and5 mM MgSO4 in Earle's balanced salt solution). At a concentration of 2.5%, ALM significantly reduced CoCl₂-induced cell loss. This protective effect persisted even when ALM was administered 1 h after the insult. We used transient middle cerebral artery occlusion to investigate the therapeutic effects of ALM in vivo. Rats were randomly assigned to two groups-the experimental (ALM) and control (saline) groups-and infusion was administered during the ischemia for 1 h. The infarction area was significantly reduced in the ALM group compared with the control group (5.0% ± 2.0% vs. 23.5% ± 5.5%, p = 0.013). Neurological deficits were reduced in the ALM group compared with the control group (modified Longa score: 0 [0-1] vs. 2 [1-2], p = 0.047). This neuroprotective effect was substantiated by a reduction in the levels of various neuronal injury markers in plasma. These results demonstrate the neuroprotective effects of ALM and may provide a new therapeutic strategy for ischemic stroke.

Pathology-related changes in cardiac energy metabolites, inflammatory response and reperfusion injury following cardioplegic arrest in patients undergoing open-heart surgery

Introduction

Changes in cardiac metabolites in adult patients undergoing open-heart surgery using ischemic cardioplegic arrest have largely been reported for non-ventricular tissue or diseased left ventricular tissue, with few studies attempting to assess such changes in both ventricular chambers. It is also unknown whether such changes are altered in different pathologies or linked to the degree of reperfusion injury and inflammatory response. The aim of the present work was to address these issues by monitoring myocardial metabolites in both ventricles and to establish whether these changes are linked to reperfusion injury and inflammatory/stress response in patients undergoing surgery using cold blood cardioplegia for either coronary artery bypass graft (CABG, n = 25) or aortic valve replacement (AVR, n = 16).

Methods

Ventricular biopsies from both left (LV) and right (RV) ventricles were collected before ischemic cardioplegic arrest and 20 min after reperfusion. The biopsies were processed for measuring selected metabolites (adenine nucleotides, purines, and amino acids) using HPLC. Blood markers of cardiac injury (Troponin I, cTnI), inflammation (IL- 6, IL-8, Il-10, and TNFα, measured using Multiplex) and oxidative stress (Myeloperoxidase, MPO) were measured pre- and up to 72 hours post-operatively.

Results

The CABG group had a significantly shorter ischemic cardioplegic arrest time (38.6 ± 2.3 min) compared to AVR group (63.0 ± 4.9 min, p = 2 x 10-6). Cardiac injury (cTnI release) was similar for both CABG and AVR groups. The inflammatory markers IL-6 and Il-8 were significantly higher in CABG patients compared to AVR patients. Metabolic markers of cardiac ischemic stress were relatively and significantly more altered in the LV of CABG patients. Comparing diabetic and non-diabetic CABG patients shows that only the RV of diabetic patients sustained major ischemic stress during reperfusion and that diabetic patients had a significantly higher inflammatory response.

Discussion

CABG patients sustain relatively more ischemic stress, systemic inflammatory response and similar injury and oxidative stress compared to AVR patients despite having significantly shorter cross-clamp time. The higher inflammatory response in CABG patients appears to be at least partly driven by a higher incidence of diabetes amongst CABG patients. In addition to pathology, the use of cold blood cardioplegic arrest may underlie these differences.

Efficacy of Whole-Blood Del Nido Cardioplegia Compared with Diluted Del Nido Cardioplegia in Coronary Artery Bypass Grafting: A Retrospective Monocentric Analysis of Pakistan

Background and Objectives: Cardioplegia is one of the most significant components used to protect the myocardium during cardiac surgery. There is a paucity of evidence regarding the utilization of whole-blood Del Nido cardioplegia (WB-DNC) on clinical outcomes in coronary artery bypass grafting (CABG). The purpose of this retrospective cross-sectional study is to compare the effectiveness of diluted (blood to crystalloid; 1:4) Del Nido cardioplegia (DNC) with WB-DNC in patients who underwent elective CABG in a tertiary care hospital in Lahore-Pakistan. Materials and Methods: This was a retrospective descriptive study conducted at the Department of Cardiovascular Surgery, King Edward Medical University, Lahore. The medical database of all consecutive patients admitted from January 2018 to March 2020 and who fulfilled the inclusion criteria were reviewed. Results: Out of 471 patients admitted during the study period, 450 underwent various elective cardiac surgeries. Out of 450, 321 patients (71.33%) were operated on for CABG. Only 234/321 (72.89%) CABG patients fulfilled our inclusion criteria; 120 (51.28%) patients received WB-DNC, while 114 (48.71%) patients were administered with DNC. The former group presented with better clinical outcomes compared with the latter in terms of lesser requirements of inotropic support, low degree of hemodilution, shorter in-hospital stay, improved renal function, and cost-effectiveness. Peak values of serum Troponin-T (Trop-T), creatine kinase-myocardial band (CK-MB) release, and activated clotting time (ACT) were also lower in the WB-DNC group compared with the DNC group. Conclusions: The WB-DNC conferred better myocardial protection, improved early clinical outcomes, and also proved to be economical for patients undergoing elective CABG compared with classical crystalloid cardioplegia solution.

HTK versus multidose cardioplegias for myocardial protection in adult cardiac surgery: A meta-analysis

BACKGROUND

Histidine-tryptophan-ketoglutarate (HTK) cardioplegia for myocardial protection obviates the need for maintenance cardioplegia doses, and thus allows for greater focus on procedure accuracy. The aim of this meta-analysis is to evaluate the safety and efficacy of HTK versus multidose cardioplegias during cardiac surgery in an adult population.

METHODS

Electronic searches were performed using PubMed, Science Direct, and Google Scholar databases. The key search terms included HTK cardioplegia AND cardiac surgery AND adult. This was followed by a meta-analysis investigating cardiopulmonary bypass (CPB) duration, cross-clamp duration, spontaneous defibrillation, inotropic support, mortality, atrial fibrillation, creatine kinase muscle brain band (CK-MB) and troponin I (TnI).

RESULTS

Seven randomized controlled trials (n = 804) were analyzed. Spontaneous defibrillation following aortic cross-clamp removal significantly favored HTK (odds ratio [OR], 2.809; 95% confidence interval [CI], 1.574 to 5.012; I²  = 0%; p < .01). There were no other notable significant differences between HTK and multidose cardioplegia in any of the parameters measured. In particular, the OR for mortality was 1.237 (95% CI, 0.385 to 3.978; I²  = 0%; p = .721) and the mean difference for CPB duration overall was 2.072 min (95% CI, -2.405 to 6.548; I²  = 74%; p = .364).

CONCLUSION

HTK is safe and effective during adult cardiac surgery when compared with multidose cardioplegias for myocardial protection during surgical correction of acquired pathology in the adult population. HTK may, therefore, be suitable for complex cases or those of extensive duration, without the prospect of increased postoperative morbidity or mortality.