Blood versus crystalloid cardioplegia for pediatric cardiac surgery: a meta-analysis

Hyperkalemic or Low Potassium Cardioplegia Protects against Reduction of Energy Metabolism by Oxidative Stress

Open-heart surgery is often an unavoidable option for the treatment of cardiovascular disease and prevention of cardiomyopathy. Cardiopulmonary bypass surgery requires manipulating cardiac contractile function via the perfusion of a cardioplegic solution. Procedure-associated ischemia and reperfusion (I/R) injury, a major source of oxidative stress, affects postoperative cardiac performance and long-term outcomes. Using large-scale liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based metabolomics, we addressed whether cardioplegic solutions affect the baseline cellular metabolism and prevent metabolic reprogramming by oxidative stress. AC16 cardiomyocytes in culture were treated with commonly used cardioplegic solutions, High K+ (HK), Low K+ (LK), Del Nido (DN), histidine-tryptophan-ketoglutarate (HTK), or Celsior (CS). The overall metabolic profile shown by the principal component analysis (PCA) and heatmap revealed that HK or LK had a minimal impact on the baseline 78 metabolites, whereas HTK or CS significantly repressed the levels of multiple amino acids and sugars. H2O2-induced sublethal mild oxidative stress causes decreases in NAD, nicotinamide, or acetylcarnitine, but increases in glucose derivatives, including glucose 6-P, glucose 1-P, fructose, mannose, and mannose 6-P. Additional increases include metabolites of the pentose phosphate pathway, D-ribose-5-P, L-arabitol, adonitol, and xylitol. Pretreatment with HK or LK cardioplegic solution prevented most metabolic changes and increases of reactive oxygen species (ROS) elicited by H2O2. Our data indicate that HK and LK cardioplegic solutions preserve baseline metabolism and protect against metabolic reprogramming by oxidative stress.

Comparative effects of different types of cardioplegia in cardiac surgery: A network meta-analysis

Objective

To compare the outcomes of four types of cardioplegia during cardiac surgery: del Nido (DN), blood cardioplegia (BC), histidine-tryptophan-ketoglutarate (HTK) and St. Thomas.

Methods

Randomized controlled trials (RCTs) and observational cohort studies from 2005 to 2021 were identified in PubMed, Embase, and Cochrane databases. Data were extracted for the primary endpoint of perioperative mortality as well as the following secondary endpoints: atrial fibrillation, renal failure, stroke, use of an intra-aortic balloon pump, re-exploration, intensive care unit stay and hospital stay. A network meta-analysis comparing all four types of cardioplegia was performed, as well as direct meta-analysis comparing pairs of cardioplegia types.

Results

Data were extracted from 18 RCTs and 49 observational cohort studies involving 18,191 adult patients (55 studies) and 1,634 children (12 studies). Among adult patients, risk of mortality was significantly higher for HTK (1.89, 95% CI 1.10, 3.52) and BC (RR 1.73, 95% CI 1.22, 2.79) than for DN. Risk of atrial fibrillation was significantly higher for BC (RR 1.41, 95% CI 1.09, 1.86) and DN (RR 1.51, 95% CI 1.15, 2.03) than for HTK. Among pediatric patients, no significant differences in endpoints were observed among the four types of cardioplegia.

Conclusions

This network meta-analysis suggests that among adult patients undergoing cardiac surgery, DN may be associated with lower perioperative mortality than HTK or BC, while risk of atrial fibrillation may be lower with HTK than with BC or DN.

Celsior® crystalloid cardioplegia versus standard hyperkalemic normothermic blood cardioplegia: Analysis of myocardial protection in elective mitral valve repair

INTRODUCTION

With the increase and refinement of video assisted mitral valve surgery, cristalloïd cardioplegia started regaining popularity. The aim of our study was to evaluate the effectiveness of Celsior^®, a crystalloid cardioplegic solution, on myocardial protection in elective surgical mitral valve repair in comparison to blood based hyperkalemic cardioplegia.

METHODS

In this observational retrospective study, all consecutive elective isolated surgical mitral valve repair where Celsior^® or normothermic hyperkalemic blood cardioplegia were used were included. Primary endpoint was any sign of myocardial protection failure (troponin levels, need for inotropic or mechanical support, rhythm disturbances, mortality). Secondary endpoint was Celsior^® safety (allergic reactions, bleeding, organ toxicities).

RESULTS

From January 2009 to August 2016, 382 patients underwent elective isolated mitral valve repair in whom normothermic hyperkalemic blood cardioplegia (n = 181) or Celsior^® (n = 201) were used. There were no statistically significant differences in baseline characteristics including Euroscore 2. Peak troponin (pg/ml) release and 30-days mortality were not statistically different. Need for cardioversion was significantly more frequent in the Celsior^® group (47% vs 13%, p < 0.001). There was no statistical difference in post-operative atrial fibrillation, permanent pacemaker implantation, reoperation for bleeding, transfusion, acute kidney injury, haemoglobin at discharge or length of stay. No allergic reaction to Celsior^® occurred.

CONCLUSION

Effective myocardial protection was achieved with the Celsior^® cardioplegic solution with no unexpected toxicity. Celsior^® may be an efficacious and safe cardioprotective strategy in mitral valve repair.

Myocardial protection in the arterial switch operation: Custodiol versus cold blood cardioplegia

OBJECTIVES

The optimal myocardial protective solution in the neonatal arterial switch operation remains controversial. The aim of this study was to demonstrate that Bretschneider's histidine-tryptophan-ketoglutarate crystalloid solution (Custodiol) offers protection at least similar to that of cold blood cardioplegia.

METHODS

Patients who underwent the neonatal arterial switch operation with Custodiol between January 2016 and December 2018 (n = 23) were compared with an historical cohort from August 2010 to December 2015 in which cold blood cardioplegia was used (n = 41). A linear mixed-effect model for repeated measures was performed to test the recovery of myocardial function based on inotropic and vasoactive inotropic scores, cardiac enzyme release and left ventricular ejection fraction.

RESULTS

Patients in the cold blood cardioplegia group had higher inotropic scores in the first 24 h (0 h, P = 0.001 and 24 h, P = 0.006) and higher vasoactive inotropic scores in the first 72 h (0 h, 24 h and 48 h, P < 0.001; 72 h, P = 0.012). Cardiac troponin-I concentrations were higher in the cold blood cardioplegia group at postoperative hours 1-72 (1 h, 6 h, 12 h and 24 h, P < 0.001; 48 h, P = 0.001 and 72 h, P = 0.003). Creatinine-kinase-MB concentrations were higher in the cold blood cardioplegia group at postoperative hours 1-24 (1 h, 6 h and 12 h, P < 0.001; 24 h, P = 0.042). The left ventricular ejection fraction was higher in the Custodiol group just after the operation (P = 0.005), at 24 h (P = 0.001) and on the first day without inotropic support (P = 0.011).

CONCLUSIONS

Neonatal myocardium protected with Custodiol during the arterial switch operation presented optimal ventricular function recovery with less inotropic support and less myocardial damage compared with cold blood cardioplegia.

Cardioplegia in paediatric cardiac surgery: a systematic review of randomized controlled trials

OBJECTIVES

Cardioplegia is the primary method for myocardial protection during cardiac surgery. We conducted a systematic review of randomized controlled trials of cardioplegia in children to evaluate the current evidence base.

METHODS

We searched MEDLINE, CENTRAL and LILACS and manually screened retrieved references and systematic reviews to identify all randomized controlled trials comparing cardioplegia solutions or additives in children undergoing cardiac surgery published in any language; secondary publications and those reporting inseparable adult data were excluded. Two or more reviewers independently screened studies for eligibility and extracted data; the Cochrane Risk of Bias tool was used to assess for potential biases.

RESULTS

We identified 26 trials randomizing 1596 children undergoing surgery; all were single-centre, Phase II trials, recruiting few patients (median 48, interquartile range 30-99). The most frequent comparison was blood versus crystalloid in 10 (38.5%) trials, and the most common end points were biomarkers of myocardial injury (17, 65.4%), inotrope requirements (15, 57.7%) and length of stay in the intensive care unit (11, 42.3%). However, the heterogeneity of patients, interventions and reported outcome measures prohibited meta-analysis. Overall risk of bias was high in 3 (11.5%) trials, unclear in 23 (88.5%) and low in none.

CONCLUSIONS

The current literature on cardioplegia in children contains no late phase trials. The small size, inconsistent use of end points and low quality of reported trials provide a limited evidence base to inform practice. A core outcome set of clinically important, standardized, validated end points for assessing myocardial protection in children should be developed to facilitate the conduct of high-quality, multicentre trials.

PROSPERO registration

CRD42017080205.

Comparison between blood and non-blood cardioplegia in tetralogy of Fallot

BACKGROUND

Cardioplegia is an integral part of myocardial protection. The superiority of blood cardioplegia in adult patients has been reported. However, this is yet to be studied in cyanotic pediatric patients.

METHODS

A randomized open-label trial was conducted in 70 patients with tetralogy of Fallot. They were divided into two groups: 35 patients had crystalloid cardioplegia (controls), and 35 had blood cardioplegia. Lactate and coronary oxygen extraction in arterial blood and the coronary sinus were measured immediately after cessation of cardiopulmonary bypass, 15 and 30 min later. Postoperative mortality, major adverse cardiac events, mechanical ventilation time, inotrope administration, arrhythmias, right ventricular function, intensive care unit and hospital length of stay were observed.

RESULTS

There were no significant differences in clinical outcomes or lactate levels. There was a significant difference in coronary oxygen extraction immediately and 15 min after cessation of cardiopulmonary bypass ( p = 0.038, p = 0.015).

CONCLUSION

Blood cardioplegia gave a better postoperative oxygen extraction value but there were no differences in myocardial damage or clinical outcome between the two groups.

Type of cardioplegic solution as a factor influencing the clinical outcome of open-heart congenital procedures

Introduction

Cardioplegia is one of the most important modalities of myocardial protection during heart surgery.

Aim

To assess the impact of blood cardioplegia on postoperative variables, in comparison with two types of crystalloid cardioplegic solutions during pediatric heart surgery.

Material and methods

One thousand one hundred and twenty-nine patients underwent surgical correction of congenital heart disease with cardioplegia administration between 2006 and 2012. Nonlinear regression models of postoperative low cardiac output syndrome (LCOS) incidence, catecholamine index and total complication count were developed using a genetic algorithm. The Akaike information criterion was applied for selection of the best model. The following explanatory variables were evaluated: cardioplegia type (ST - Saint Thomas, n = 440; FR - Fresenius, n = 432; BL - Calafiore, n = 257), congenital heart diseases (CHD) type, age, sex, genetic disorder presence, body surface area (BSA), cardiopulmonary bypass (CBP) time, aortic cross-clamp time, operation urgency, redo surgery, surgeon.

Results

Low cardiac output syndrome presence and higher than average catecholamine indexes were negatively influenced by use of crystalloid cardioplegia (ST or FR), presence of specific CHDs, redo surgery and prolonged CBP time. Increased complication count was related to: crystalloid cardioplegia, presence of specific CHDs, redo surgery, urgency of operation, operation time and CBP time. Higher BSA had a protective effect against higher catecholamine index and increased complication count. Older age was protective against LCOS.

Conclusions

Cardioplegic solutions type influences postoperative variables in children after heart surgery by the negative impact of crystalloid cardioplegia. Blood cardioplegia presents potential advantages for patients - its application may reduce the incidence of low cardiac output syndrome and related complications.

Blood cardioplegia benefits only patients with a long cross-clamp time

INTRODUCTION

A clear advantage of blood versus crystalloid cardioplegia has not yet been observed in smaller population studies. The purpose of this article was to further investigate the clinical outcomes of blood versus crystalloid cardioplegia in a large propensity-matched cohort of patients who underwent cardiac surgery.

METHODS

The study was a single-centre study. Data was withdrawn from the Western Denmark Heart Registry, which comprises a perfusion section for each procedure. A total of 4,852 patients were propensity matched into crystalloid (CC) vs blood cardioplegia (BC) groups. The primary end points were creatinine kinase-MB (CKMB) elevation, acute myocardial infarction (AMI), stroke, dialysis, coronary angiography (CAG) and mortality (30 days and 6 months).

RESULTS

We found lower odds ratio in 30-day mortality in the BC group (OR 0.21; CI 0.06-0.68), but no difference in overall 6-month mortality. There was no difference in CKMB elevation, AMI, dialysis or stroke. Several end points were further analysed for different cross-clamp times. In the CC group, ventilation time above 600 minutes was seen more often in almost all cross-clamp time intervals (23.5 % vs 12.2 %; p<0.0001; χ²-test) and 6-month mortality was significantly higher when the cross-clamp time exceeded 210 minutes (64.3 vs 23.8; p=0.018; χ²-test).

CONCLUSIONS

We did not find clear evidence of superiority of either type in the uncomplicated patient. When prolonged cross-clamp time or postoperative ventilation is expected, this study indicates that blood cardioplegia might be preferable.

Blood Versus Crystalloid Cardioplegia in Pediatric Cardiac Surgery: A Systematic Review and Meta-analysis

The benefit of blood cardioplegia (BCP) compared to crystalloid cardioplegia (CCP) is still debatable. Our aim was to systematically review and synthesize all available evidence on the use of BCP and CCP to assess if any modality provides superior outcomes in pediatric cardiac surgery. A systematic literature search of the PubMed and Cochrane databases was performed with respect to the PRISMA statement (end-of-search date: January 30th, 2017). We extracted data on study design, demographics, cardioplegia regimens, and perioperative outcomes as well as relevant biochemical markers, namely cardiac troponin I (cTnI), lactate, and ATP levels at baseline, after reperfusion and postoperatively at 1, 4, 12, and 24 h as applicable. Data were appropriately pooled using random and mixed effects models. Our systematic review includes 56 studies reporting on a total of 7711 pediatric patients. A meta-analysis of the 10 eligible studies directly comparing BCP (n = 416) to CCP (n = 281) was also performed. There was no significant difference between the two groups with regard to cTnI and Lac at any measured time point, ATP levels after reperfusion, length of intensive care unit stay (WMD: -0.08, 95% CI -1.52 to 1.36), length of hospital stay (WMD: 0.13, 95% CI -0.85 to 1.12), and 30-day mortality (OR 1.11, 95% CI 0.43-2.88). Only cTnI levels at 4 h postoperatively were significantly lower with BCP (WMD: -1.62, 95% CI -2.07 to -1.18). Based on the available data, neither cardioplegia modality seems to be superior in terms of clinical outcomes, ischemia severity, and overall functional recovery.

A safety evaluation of profound hypothermia-induced suspended animation for delayed resuscitation at 90 or 120 min

BACKGROUND

The successful treatment of military combat casualties with penetrating injuries is significantly dependent on the time needed to get the patient to an adequate treatment facility. Profound hypothermia-induced suspended animation for delayed resuscitation (SADR) is a novel approach for inducing cardiac arrest and buying additional time for such injuries. However, the time used to safely administer circulatory arrest (CA) is controversial. The goal of this study was to evaluate the safety of hypothermia-induced SADR over 90 and 120 min time intervals.

METHODS

Sixteen male BAMA minipigs were randomized into two groups: CA90 group (90 min, n = 8) and CA120 group (120 min, n = 8). Cannulation of the right common carotid arteries and internal jugular veins was performed to establish cardiopulmonary bypass for each animal. Through the perfusion of cold organ preservation solution (OPS), cardioplegia and profound hypothermia (15 °C) were induced. After CA, cardiopumonary bypass (CPB) was restarted, and the animals were gradually re-warmed and resuscitated. The animals were assisted with ventilators until spontaneous breathing was achieved. The index of hemodynamic perioperative serum chemistry values [alanine transaminase (ALT), aspartate aminotransferase (AST), creatinine (CR), lactic dehydrogenase (LDH) and troponin T (TnT)] and survival were observed from pre-operation to 7 days post-operation.

RESULTS

Fifteen animals were enrolled in the experiment, while 1 animal in CA120 group died from surgical error. All 8 animals in CA90 group recovered, with only 1 animal displaying mild disability. However, in CA120 group, only 2 animals survived with severe disability, and the other 5 animals died after 2 days post-operation. In CA90 group, the perioperative serum chemistry values increased at 1 day post-operation (ALT 84.43 ± 18.65 U/L; AST 88.99 ± 23.19 U/L; Cr 87.90 ± 24.49 μmol/L; LDH 1894.13 ± 322.26 U/L; TnT 0.849 ± 0.135 ng/ml) but decreased to normal or almost normal levels at 7 days post-operation (ALT 52.48 ± 9.04 U/L; AST 75.23 ± 21.46 U/L; Cr 82.69 ± 18.41 μmol/L; LDH 944.67 ± 834.32 U/L; TnT 0.336 ± 0.076 ng/ml).

CONCLUSIONS

Profound hypothermia-induced SADR is an effective method for inducing cardiac arrest. Our results indicate that inducing CA for 90 min (at 15 °C) is safer than doing so for 120 min. Our results indicate that 120 min of CA at 15 °C is dangerous and can result in high mortality and severe neurological complications. Further experimentation is needed to determine whether 120 min of CA at temperatures lower than 15 °C can lead to safe recovery.