The cardioprotective effects of HTK solution and conventional blood cardioplegia in patients with atrial fibrillation undergoing valvular replacement and Cox maze III procedure

INTRODUCTION

The study was to assess the myocardial protection effects of the histidine-tryptophan-ketoglutarate (HTK) solution and the 4:1 blood cardioplegia (BC) in patients with atrial fibrillation (AF) who were subjected to valvular replacement concomitant with the Cox maze III surgery.

METHODS

A cohort of 148 individuals afflicted with AF, who received valve replacement surgery in conjunction with the Cox maze III procedure at our clinic within the period extending from 2015 to 2023, were enrolled. Subsequent to adjustment by propensity score matching (PSM), the patients were categorized into two distinct groups: the HTK group and the BC group. The primary end points assessed inotropic support requirements, complications, troponin trend, mechanical ventilation time and the intensive care unit stay. Arrhythmias, aortic cross-clamp and cardiopulmonary bypass times, and other clinical perioperative variables were considered as secondary end points.

RESULTS

No substantive disparities were observed concerning mortality rates, arrhythmias, neurological events, or renal complications. The duration of cardiopulmonary bypass and the aortic cross-clamp time did not demonstrate any marked variations between both groups, with p-values of 0.71 and 0.05, respectively. The time required for weaning from mechanical ventilation and the length of postoperative hospitalization were notably less in the group receiving HTK solution (p < 0.001 and p = 0.03, respectively). While inotropic support need was higher in the BC group (p = 0.02). Conversely, the dosage and frequency of perfusions were considerably increased in the BC group (p < 0.001 for each parameter). Within subgroups stratified by longer than 150 min of aortic cross-clamping duration, those in the BC cohort had significantly elevated peaks of cardiac troponin I (cTnI) (p = 0.01), whereas individuals in the HTK group experienced less mechanical ventilation time (p = 0.002) and shorter durations of intensive care unit admission (p < 0.001). The LVEF value in the HTK group was higher compared to that in the BC group in the 3-month follow-up data (p = 0.02).

CONCLUSIONS

Both the HTK and 4:1 blood cardioplegia could be used safely in patients with AF who were subject to valvular replacement and Cox maze III procedure. However, the utilization of HTK conferred a greater advantage in diminishing the duration of mechanical ventilation weaning and the duration of postoperative hospitalization. HTK may be a better myocardial protection in patients with long cross-clamp time. The follow-up data indicated that HTK might be superior to 4:1 blood cardioplegia in the short-medium term cardiac function.

Comparison of Bretschneider HTK cardioplegia solution and blood cardioplegia in terms of postoperative results in patients who underwent isolated supracoronary ascending aortic replacement

INTRODUCTION

Cardiac arrest with cardioplegia is the most common and reliable method of myocardial protection in cardiac surgery, but there is no definite consensus on the use of different types of cardioplegia. Two of the commonly used types of cardioplegia are Bretschneider histidine-tryptophan-ketoglutarate solution (Custodiol) and conventional blood cardioplegia. In this study, Custodiol solution and conventional blood cardioplegia used in patients with type A aortic dissection who underwent supracoronary ascending aortic replacement were aimed to be compared in terms of postoperative results.

METHODS

70 patients with type A aortic dissection who underwent supracoronary ascending aortic replacement in our clinic between January 2011 - October 2020 were included. Patients were divided into two groups, blood cardioplegia group (n = 48) and Custodiol group (n = 22) and they were compared regarding preoperative, perioperative and postoperative variables.

RESULTS

There was no significant difference between cardiopulmonary bypass time and cross-clamp time (p = 0.17 and p = 0.16, respectively). Mechanical ventilator weaning time, intensive care unit stay and hospital stay were shorter in Custodiol group (p = 0.04,p = 0.03 and p = 0.05, respectively). While inotropic support need was higher in the blood cardioplegia group (p = 0.001), there was no significant difference in terms of mortality, arrhythmia, neurological complications and renal complications.

CONCLUSIONS

Our results show that Custodiol cardioplegia solution may be superior to blood cardioplegia in reducing mechanical ventilation weaning period, intensive care and hospital stay, and reducing the use of inotropic agents in patients with type A aortic dissection undergoing supracoronary ascending aorta replacement.

Novel Strategies to Improve the Cardioprotective Effects of Cardioplegia

The use of cardioprotective strategies as adjuvants of cardioplegic solutions has become an ideal alternative for the improvement of post-surgery heart recovery. The choice of the optimal cardioplegia, as well as its distribution mechanism, remains controversial in the field of cardiovascular surgery. There is still a need to search for new and better cardioprotective methods during cardioplegic procedures. New techniques for the management of cardiovascular complications during cardioplegia have evolved with new alternatives and additives, and each new strategy provides a tool to neutralize the damage after ischemia/reperfusion events. Researchers and clinicians have committed themselves to studying the effect of new strategies and adjuvant components with the potential to improve the cardioprotective effect of cardioplegic solutions in preventing myocardial ischemia/reperfusion-induced injury during cardiac surgery. The aim of this review is to explore the different types of cardioplegia, their protection mechanisms, and which strategies have been proposed to enhance the function of these solutions in hearts exposed to cardiovascular pathologies that require surgical alternatives for their corrective progression.

Single-Dose St. Thomas Versus Custodiol® Cardioplegia for Right Mini-thoracotomy Mitral Valve Surgery

OBJECTIVE

Custodiol® and St. Thomas cardioplegia are widely employed in mini-thoracotomy mitral valve (MV) operations. One-dose of the former provides 3 h of myocardial protection. Conversely, St. Thomas solution is usually reinfused every 30 min and safety of single delivery is unknown. We aimed to compare single-shot St. Thomas versus Custodiol® cardioplegia.

METHODS

Primary endpoint of the prospective observational study was cardiac troponin T level at different post-operative time-points. Propensity-weighted treatment served to adjust for confounding factors.

RESULTS

Thirty-nine patients receiving St. Thomas were compared with 25 patients receiving Custodiol® cardioplegia; cross-clamping always exceeded 45 min. No differences were found in postoperative markers of myocardial injury. Ventricular fibrillation at the resumption of electric activity was more frequent following Custodiol® cardioplegia (P = .01).

CONCLUSION

Effective myocardial protection exceeding 1 h of ischemic arrest can be achieved with a single-dose St. Thomas cardioplegia in selected patients undergoing right mini-thoracotomy MV surgery.

Theoretical and Practical Aspects in the Use of Bretschneider Cardioplegia

The race for an ideal cardioplegic solution has remained enthusiastic since the beginning of the modern cardiac surgery era. The Bretschneider solution, belonging to the “intracellular cardioplegic” group, is safe and practical in myocardial protection during ischemic time. Over time, some particular concerns have arisen regarding the effects on cardiac metabolism and postoperative myocardial functioning. This paper reviews the most important standpoints in terms of theoretical and practical analyses.

Comparable prognosis in different neonatal histidine-tryptophan-ketoglutarate dosage management

Background:

Histidine-tryptophan-ketoglutarate (HTK) is a solution commonly used for organ transplantation. However, there is no certified fixed regimen for on-pump heart surgery in neonates. We aimed to retrospectively evaluate the outcomes related to different HTK dosages and to analyze the safety of high-dosage perfusion.

Methods:

A total of 146 neonates who underwent on-pump heart surgery with single-shot HTK perfusion were divided into two groups according to HTK dosages: a standard-dose (SD) group (n = 63, 40 mL/kg < HTK ≤ 60 mL/kg) and a high-dose (HD) group (n = 83, HTK >60 mL/kg). Propensity score matching (PSM) was performed to control confounding bias.

Results:

The SD group had a higher weight (3.7 ± 0.4 vs. 3.4 ± 0.4 kg, P < 0.0001), a lower proportion of complete transposition of the great artery (69.8% vs. 85.5%, P = 0.022), a lower cardiopulmonary bypass (CPB) time (123.5 [108.0, 136.0] vs. 132.5 [114.8, 152.5] min, P = 0.034), and a lower aortic x-clamp time (82.9 ± 27.1 vs. 95.5 ± 26.0 min, P = 0.005). After PSM, 44 patients were assigned to each group; baseline characteristics and CPB parameters between the two groups were comparable. There were no significant differences in peri-CPB blood product consumption after PSM (P > 0.05). The incidences of post-operative complications were not significantly different between the two groups. There were no significant differences in ventilation time, intensive care unit stay, and post-operative hospital stay (P > 0.05). Follow-up echocardiography outcomes at 1 month, 3 to 6 months, and 1 year showed that left ventricular ejection fraction and end-diastolic dimension were comparable between the two groups.

Conclusions:

In neonatal on-pump cardiac surgery patients, single-shot HD (>60 mL/kg) HTK perfusion had a comparable heart protection effect and short-term post-operative prognosis as standard dosage perfusion of 40 to 60 mL/kg. Thus, this study provides supporting evidence of the safety of HD HTK perfusion.

Guidelines for enhanced recovery after cardiac surgery. Consensus document of Spanish Societies of Anesthesia (SEDAR), Cardiovascular Surgery (SECCE) and Perfusionists (AEP)

The ERAS guidelines are intended to identify, disseminate and promote the implementation of the best, scientific evidence-based actions to decrease variability in clinical practice. The implementation of these practices in the global clinical process will promote better outcomes and the shortening of hospital and critical care unit stays, thereby resulting in a reduction in costs and in greater efficiency. After completing a systematic review at each of the points of the perioperative process in cardiac surgery, recommendations have been developed based on the best scientific evidence currently available with the consensus of the scientific societies involved.

Acute isotonic hyponatremia after single dose histidine-tryptophan-ketoglutarate cardioplegia: an observational study

INTRODUCTION

Histidine-tryptophan-ketoglutarate cardioplegia is used for prolonged myocardial protection in complex cardiac surgery. Administration leads to acute hyponatremia in a majority of patients, because of its low sodium concentration (15 mmol/L). However, histidine-tryptophan-ketoglutarate solution's osmolality is slightly hypertonic (310 mOsm/kg). Hypothesized was that acute isotonic hyponatremia will be induced, which does not need to be corrected with hypertonic saline.

METHODS

Cardiac surgery patients who received histidine-tryptophan-ketoglutarate cardioplegia were included in this prospective single center study. Serial blood samples were taken from each patient at five different time points: after induction of anesthesia (T1) and 10 minutes (T2), 6 hours (T3), 12 hours (T4), and 18 hours (T5) after administration of histidine-tryptophan-ketoglutarate cardioplegia, respectively. Blood samples were analyzed for sodium concentration, osmolality, and acid-base balance.

RESULTS

Twenty-five patients were included. Median blood sodium levels decreased from 140 [138-141] at T1 to 128 [125-130] mmol/L at T2 (p < 0.001). At T3, T4, and T5, median blood sodium concentrations were 136 [134-138], 139 [137-140], and 140 [137-142] mmol/L, respectively. Median osmolality was 289 [286-293] at T1 and increased to 296 [291-299] mOsm/kg (p < 0.001) at T2. At T3, T4, and T5, osmolality was 298 [292-302], 298 [294-304], and 300 [297-306] mOsm/kg, respectively. Median pH decreased from 7.38 [7.36-7.40] at T1 to 7.30 [7.27-7.32] at T2 (p < 0.001).

CONCLUSION

Administration of histidine-tryptophan-ketoglutarate cardioplegia during cardiac surgery leads to acute moderate to severe isotonic hyponatremia, which resolves spontaneously in the first 18 hours perioperatively. Correction with hypertonic saline is not necessary.

Custodiol cardioplegia solution compared to cold blood cardioplegia in pediatric cardiac surgery: a single-institution experience

OBJECTIVE

Custodiol is an intracellular, crystalloid cardioplegia solution that is a single-dose alternative to multi-dose cold blood cardioplegia; however, there is scarce data regarding its use in infants and children. The objective of this study was to compare its impact on myocardial function in infants.

METHODS

Single-center retrospective review including 132 patients <12 months old undergoing biventricular repair. There were 106 patients who received single-dose Custodiol and 27 patients who received multi-dose blood cardioplegia. Demographic and echocardiographic data were compared between the two groups.

RESULTS

Patients receiving Custodiol were slightly younger (100 ± 62 days) and lower weight (4.7 ± 1.3 kg) compared to 152 ± 86 days and 5.2 ± 1.3 kg for blood cardioplegia (p < 0.05). The Society of Thoracic Surgeons/European Association for Cardio-Thoracic Surgery Congenital Heart Surgery score was similar between both groups. Average cardiopulmonary bypass time was similar between both groups (Custodiol 93 ± 54 minutes vs. blood 81 ± 44 minutes, p = 0.46) as was aortic cross-clamp time (Custodiol 58 ± 33 minutes vs. cold blood 53 ± 33 minutes, p = 0.62). Pre-operative left ventricular ejection fraction was similar for blood 73 ± 8% versus Custodiol 70 ± 9%, p = 0.21. There was also no intergroup difference in left ventricular ejection fraction 24 hours post op (blood 64 ± 9% vs. Custodiol 65 ± 12%, p = 0.53) or at discharge (blood 66 ± 10% vs. Custodiol 66 ± 11%, p = 0.95). The pre-operative right ventricle function by fractional area change was also similar in blood cardioplegia (46 ± 13%) versus Custodiol (48 ± 9%, p = 0.38) and showed similar drops in parameters in the two groups 24 hours after surgery and at discharge.

CONCLUSION

Single-dose Custodiol is as safe as blood cardioplegia for myocardial protection in congenital cardiac surgery for the cross-clamp times evaluated in this study. Evaluation at longer cross-clamp times would be helpful to determine if there is a greater benefit to single-dose Custodiol versus more repeated doses of blood cardioplegia for longer cross-clamp times.

Single- versus multidose cardioplegia in adult cardiac surgery patients: A meta-analysis

OBJECTIVE

To compare outcomes of single (intervention group: del Nido [DN], and histamine-tryptophan-ketoglutarate) versus multidose (control group) cardioplegia in the adult cardiac surgery patients.

METHODS

Medical search engines were interrogated to identify relevant randomized controlled trials and propensity-score matched cohorts. Meta-analysis was conducted for primary (in-hospital/30-day mortality) and secondary (ischemic and cardiopulmonary bypass [CPB] times, reperfusion fibrillation, peak of cardiac enzymes, myocardial infarction) endpoints. Subgroup analyses were conducted for study design and type of intervention, and meta-regression for primary outcome included type of surgery and left ventricular ejection fraction as moderators.

RESULTS

Ten randomized controlled trials and 13 propensity-score matched cohorts were included, reporting on 5516 patients. Estimates are expressed as (parameter value [OR, odds ratio; MD, mean difference; SMD, standardized mean difference]/unit of measure [95% confidence interval], P value). DN reduced ischemic time (MD, -7.18 minutes [-12.52 to -1.84], P < .01), CPB time (MD, -10.44 minutes [-18.99 to -1.88], P .01), reperfusion fibrillation (OR, 0.16 [0.05-0.54], P < .01), and cardiac enzymes (SMD -0.17 [-0.29, 0.05], P < .01) compared with multidose cardioplegia. None of these beneficial effects were reproduced by histamine-tryptophan-ketoglutarate, which instead increased CPB time (MD, 2.04 minutes [0.73-3.37], P < .01) and reperfusion fibrillation (OR, 1.80 [1.20-2.70], P < .01). There was no difference in mortality and myocardial infarction between single and multidose, independently of type of surgery or left ventricular ejection fraction.

CONCLUSIONS

DN decreases operative times, reperfusion fibrillation, and surge of cardiac enzymes compared with multidose cardioplegia.

Safe cross-clamp time using Custodiol®-histidine-tryptophan-ketoglutarate cardioplegia in the adult

INTRODUCTION

Safe cross-clamp time using single-dose Custodiol^®-histidine-tryptophan-ketoglutarate cardioplegia has not been established conclusively.

METHODS

Immediate post-operative outcomes of 1,420 non-consecutive, cardiac surgery patients were reviewed retrospectively. Predictors of a combined endpoint made of in-hospital mortality and any major complication post-surgery were found with the multivariable method. Analysis of variance was used to evaluate the impact of cross-clamp time on most relevant complications. Discriminatory power and cut-off value of cross-clamp time were established for in-hospital mortality and each of the major complications (receiver operating characteristic curve analysis). A comparative analysis (with propensity matching) with multidose cold blood cardioplegia on in-hospital mortality post-surgery was performed in non-coronary surgery patients.

RESULTS

Coronary, aortic valve and mitral valve surgery and surgery on thoracic aorta were performed in 45.4%, 41.9%, 49.5%, 20.6% of cases, respectively. In-hospital mortality and the rate of any major complication post-surgery were 6.5% and 41.9%, respectively. Cross-clamp time had significant impact on in-hospital mortality and almost all major post-operative complications, except neurological dysfunctions (p = 0.084), myocardial infarction (p = 0.12) and mesenteric ischaemia (p = 0.85). Areas under the receiver operating characteristic curve and the optimal cut-off values for in-hospital mortality and any major complication were of 0.657, 0.594, >140 and >127 minutes, respectively. Comorbidities-adjusted odds ratio for any major complication of cross-clamp time <127 minutes was 1.86 (p < 0.0001). Despite similar in-hospital mortality (p = 0.57), there was an earlier significant increase of mortality in Custodiol-HTK than in multidose cold blood propensity-matched, non-coronary surgery patients.

CONCLUSIONS

The use of Custodiol-HTK cardioplegia is associated with a low risk of serious post-operative complications provided that cross-clamp time is of 2 hours or less.

Myocardial protection in on-pump coronary artery bypass grafting surgery: analysis of the effectiveness of the use of retrograde Celsior®

BACKGROUND

We analyzed the adequacy of the myocardial protection achieved with a single dose of retrograde crystalloid Celsior®, compared with an accepted standard (microplegia), in on-pump coronary artery bypass grafting surgery (CABG).

METHODS

This was a retrospective comparative clinical study conducted in a single institution that included all the patients operated on who had elective isolated on-pump CABG, from March 2006 to June 2014. We evaluated maximum postoperative troponin T (TnT) as a marker of myocardial damage, adjusted for possible confounders using propensity score matching. We also analyzed markers of recovery of myocardial function, and the safety of the intravenous use of Celsior®.

RESULTS

During the study period, 261 patients were included, divided in two groups: (a) continuous retrograde blood-based microplegia (114 patients); (b) retrograde single-dose crystalloid Celsior® (147 patients). The propensity score adjusted maximum TnT was significantly lower in the Celsior group [average treatment effect = -0.55 ng/dl; 95% confidence interval (CI) -1.10 to -0.1 ng/dl; p = 0.048]. There were no differences in the postoperative use of intra-aortic balloon of counterpulsation or in the requirements of high-dose inotropic medications. In-hospital mortality was equivalent in both study groups ( p = 0.73); surgical re-exploration because of bleeding was equivalent ( p = 0.37). There were no differences in prolonged mechanical ventilation ( p = 0.65) and intensive care unit length of stay ( p = 0.87).

CONCLUSION

An isolated single dose of retrograde Celsior® may be an effective and safe myocardial protection strategy in on-pump CABG.

Impact of reduced left ventricular function on repairing acute type A aortic dissection: Outcome and risk factors analysis from a single institutional experience

Preoperative left ventricular dysfunction is a risk factor for postoperative mortality and morbidity in cardiovascular surgeries with cardiopulmonary bypass, including thoracic aortic surgery. Using a retrospective study design, this study aimed to clarify the short- and mid-term outcomes of patients who underwent acute type A aortic dissection (ATAAD) repair with reduced left ventricular function.Between July 2007 and February 2018, a total of 510 adult patients underwent surgical repair of ATAAD in a single institution. The patients were classified as having left ventricular ejection fraction (LVEF) <50% (low EF group, n = 86, 16.9%) and LVEF ≥50% (normal group, n = 424, 83.1%) according to transesophageal echocardiographic assessment at the operating room. Preoperative demographics, surgical information, and postoperative complication were compared between the two groups. Three-year survival was analyzed using the Kaplan-Meier actuarial method. Serial echocardiographic evaluations were performed at 1, 2, and 3 years postoperation.Demographics, comorbidities, and surgical procedures were generally homogenous between the 2 groups, except for a lower rate of aortic arch replacement in the low EF group. The averaged LVEFs were 44.3 ± 2.5% and 65.8 ± 6.6% among the low EF and normal groups, respectively. The patients with low EF had higher in-hospital mortality (23.3% versus 13.9%, P = .025) compared with the normal group. Multivariate analysis revealed that intraoperative myocardial failure requiring extracorporeal membrane oxygenation support was an in-hospital mortality predictor (odds ratio, 16.99; 95% confidence interval, 1.23-234.32; P = .034), as was preoperative serum creatinine >1.5 mg/dL. For patients who survived to discharge, the 3-year cumulative survival rates were 77.8% and 82.1% in the low EF and normal groups, respectively (P = .522). The serial echocardiograms revealed no postoperative deterioration of LVEF during the 3-year follow-up.Even with a more conservative aortic repair procedure, the patients with preoperative left ventricular dysfunction are at higher surgical risk for in-hospital mortality. However, once such patients are able to survive to discharge, the midterm outcome can still be promising.

Histidine Metabolism After Bretschneider Cardioplegia in Cardiac Surgical Patients

Bretschneider (histidine-tryptophan-ketoglutarate) solution with its high histidine concentration (198 mM) is one of many cardioplegic solutions, which are routinely used for cardiac arrest. The aim of this study was to evaluate the physiological biochemical degradation of administered histidine to histamine and its major urinary metabolite N-methylimidazole acetic acid. A total number of thirteen consecutive patients scheduled for elective isolated coronary artery bypass grafting with cardiopulmonary bypass were enrolled in the prospective observational designed study at the Department of Thoracic and Cardiovascular Surgery between 04/2016 and 06/2016. Patients received 1.7 l Bretschneider solution on average. Before and at the end of operation as well as in the postoperative course, urine samples gathered from the urinary catheter bag were analyzed. During the operative period, urinary histidine concentration significantly increased from 29 µmol/mmol creatinine to 9,609 µmol/mmol creatinine. Postoperatively, histidine excretion reduced while histamine as well as N-methylimidazole acetic acid excretion rose significantly. Patients showed elevated levels of histidine, histamine as well as N-methylimidazole acetic acid in urine, but no unmanageable hemodynamic instability possibly arising from the histamine’s biological properties. Chemically modified histidine might reduce uptake and metabolization while maintaining the advantages of buffer capacity.

Myocardial protection during minimally invasive cardiac surgery through right mini-thoracotomy

BACKGROUND

Myocardial damage is an independent predictor of adverse outcome following cardiac surgery and myocardial protection is one of the key factors to achieve successful outcomes. Cardioplegia with Custodiol is currently the most used cardioplegia during minimally invasive cardiac surgery (MICS). Different randomized controlled trials compared blood and Custodiol cardioplegia in the context of traditional cardiac surgery. No data are available for MICS.

AIM

The aim of this study was to compare the efficacy of cold blood versus Custodiol cardioplegia during MICS.

METHOD

We retrospectively evaluated 90 patients undergoing MICS through a right mini-thoracotomy in a three-year period. Myocardial protection was performed using cold blood (44 patients, CBC group) or Custodiol (46 patients, Custodiol group) cardioplegia, based on surgeon preference and complexity of surgery.

RESULTS

The primary outcomes were post-operative cardiac troponin I (cTnI) and creatine kinase MB (CKMB) serum release and the incidence of Low Cardiac Output Syndrome (LCOS). Aortic cross-clamp and cardiopulmonary bypass times were higher in the Custodiol group. No difference was observed in myocardial injury enzyme release (peak cTnI value was 18±46 ng/ml in CBC and 21±37 ng/ml in Custodiol; p=0.245). No differences were observed for mortality, LCOS, atrial or ventricular arrhythmias onset, transfusions, mechanical ventilation time duration, intensive care unit and total hospital stay.

CONCLUSIONS

Custodiol and cold blood cardioplegic solutions seem to assure similar myocardial protection in patients undergoing cardiac surgery through a right mini-thoracotomy approach.

Myocardial Protection and Financial Considerations of Custodiol Cardioplegia in Minimally Invasive and Open Valve Surgery

Objective

Single-dose antegrade crystalloid cardioplegia with Custodiol-HTK (histidine-tryptophan-ketoglutarate) has been used for many years. Its safety and efficacy were established in experimental and clinical studies. It is beneficial in complex valve surgery because it provides a long period of myocardial protection with a single dose. Thus, valve procedures (minimally invasive or open) can be performed with limited interruption. The aim of this study is to compare the use of Custodiol-HTK cardioplegia with traditional blood cardioplegia in patients undergoing minimally invasive and open valve surgery.

Methods

A single-institution, retrospective case-control review was performed on patients who underwent valve surgery in Lee Memorial Health System at either HealthPark Medical Center or Gulf Coast Medical Center from July 1, 2011, through March 7, 2015. A total of 181 valve cases (aortic or mitral) performed using Custodiol-HTK cardioplegia were compared with 181 cases performed with traditional blood cardioplegia. Each group had an equal distribution of minimally invasive and open valve cases. Right chest thoracotomy or partial sternotomy was performed on minimally invasive valve cases. Demographics, perioperative data, clinical outcomes, and financial data were collected and analyzed.

Results

Patient outcomes were superior in the Custodiol-HTK cardioplegia group for blood transfusion, stroke, and hospital readmission within 30 days (P < 0.05). No statistical differences were observed in the other outcomes categories. Hospital charges were reduced on average by $3013 per patient when using Custodiol-HTK cardioplegia.

Conclusions

Use of Custodiol-HTK cardioplegia is safe and cost-effective when compared with traditional repetitive blood cardioplegia in patients undergoing minimally invasive and open valve surgery.

Histidine and other amino acids in blood and urine after administration of Bretschneider solution (HTK) for cardioplegic arrest in patients: effects on N-metabolism

Bretschneider (histidine-tryptophan-ketoglutarate, HTK) solution employed for induction of cardioplegic arrest possesses a high histidine concentration (198 mM). Due to the large volume administered, massive amounts of histidine are incorporated. The aim of the study was to evaluate alterations in amino acid and nitrogen metabolism originating from histidine degradation. Between 07/2014 and 10/2014, a total of 29 consecutive patients scheduled for elective isolated coronary artery bypass grafting with cardiopulmonary bypass (CPB) were enrolled in this prospective observational study. The patients received 1.6 L cardioplegic Bretschneider solution on average. Blood gas and urine samples obtained were analyzed for amino acid as well as urea and ammonium concentrations. After CPB initiation, plasma histidine concentration greatly increased to 21,000 µM to reach 8000 µM at the end. Within the operative period, plasma concentrations of aspartate, glutamate, asparagine, alanine, and glutamine increased variable in magnitude. During the same time, urinary analysis revealed histidine excretion of 19,500 µmol in total and marked elevations in glutamate and glutamine excretion. The absolute amounts of urea and ammonium excreted additionally were 3 mmol and 8 mmol, respectively. Already during CPB, distinct amounts of the histidine administered are metabolized, mainly to other amino acids, but only small amounts to urea and ammonia. Thus, the impact of the histidine incorporated on acid–base status in the intraoperative phase is minor. On the other hand, intraoperative provision of several amino acids arising from histidine metabolism might mitigate postaggression syndrome.

Custodiol-N, the novel cardioplegic solution reduces ischemia/reperfusion injury after cardiopulmonary bypass

BACKGROUNDS

On the basis of Custodiol preservation and cardioplegic solution a novel cardioplegic solution was developed to improve the postischemic cardiac and endothelial function. In this study, we investigated whether its reduced cytotoxicity and its ability to reduce reactive oxygen species generation during hypoxic condition have beneficial effects in a clinically relevant canine model of CPB.

METHODS

12 dogs underwent cardiopulmonary bypass with 60 minutes of hypothermic cardiac arrest. Dogs were divided into 2 groups: Custodiol (n = 6) and Custodiol-N (n = 6) (addition of L-arginin, N-α-acetyl-L-histidine and iron-chelators: deferoxamine and LK-614). Left ventricular hemodynamic variables were measured by a combined pressure-volume conductance catheter at baseline and after 60 minutes of reperfusion. Coronary blood flow, myocardial ATP content, plasma nitrate/nitrite and plasma myeloperoxidase levels were also determined.

RESULTS

The use of Custodiol-N cardioplegic solution improved coronary blood flow (58 ± 7 ml/min vs. 26 ± 3 ml/min) and effectively prevented cardiac dysfunction after cardiac arrest. In addition, the myocardial ATP content (12,8 ± 1,0 μmol/g dry weight vs. 9,5 ± 1,5 μmol/g dry weight) and plasma nitrite (1,1 ± 0,3 ng/ml vs. 0,5 ± 0,2 ng/ml) were significantly higher after application of the new cardioplegic solution. Furthermore, plasma myeloperoxidase level (3,4 ± 0,4 ng/ml vs. 4,3 ± 2,2 ng/ml) significantly decreased in Custodiol-N group.

CONCLUSIONS

The new HTK cardioplegic solution (Custodiol-N) improved myocardial and endothelial function after cardiopulmonary bypass with hypothermic cardiac arrest. The observed protective effects imply that the Custodiol-N could be the next generation cardioplegic solution in the protection against ischemia-reperfusion injury in cardiac surgery.

Comparison of fractal dimension and Shannon entropy in myocytes from rats treated with histidine-tryptophan-glutamate and histidine-tryptophan cetoglutarate

INTRODUCTION

Solutions that cause elective cardiac arrest are constantly evolving, but the ideal compound has not yet been found. The authors compare a new cardioplegic solution with histidine-tryptophan-glutamate (Group 2) and other one with histidine-tryptophan-cetoglutarate (Group 1) in a model of isolated rat heart.

OBJECTIVE

To quantify the fractal dimension and Shannon entropy in rat myocytes subjected to cardioplegia solution using histidine-tryptophan with glutamate in an experimental model, considering the caspase markers, IL-8 and KI-67.

METHODS

Twenty male Wistar rats were anesthetized and heparinized. The chest was opened, the heart was withdrawn and 40 ml/kg of cardioplegia (with histidine-tryptophan-cetoglutarate or histidine-tryptophan-glutamate solution) was infused. The hearts were kept for 2 hours at 4ºC in the same solution, and thereafter placed in the Langendorff apparatus for 30 min with Ringer-Locke solution. Analyzes were performed for immunohistochemical caspase, IL-8 and KI-67.

RESULTS

The fractal dimension and Shannon entropy were not different between groups histidine-tryptophan-glutamate and histidine-tryptophan-acetoglutarate.

CONCLUSION

The amount of information measured by Shannon entropy and the distribution thereof (given by fractal dimension) of the slices treated with histidine-tryptophan-cetoglutarate and histidine-tryptophan-glutamate were not different, showing that the histidine-tryptophan-glutamate solution is as good as histidine-tryptophan-acetoglutarate to preserve myocytes in isolated rat heart.

Custodiol for myocardial protection and preservation: a systematic review

INTRODUCTION

Custodiol cardioplegia is attractive for minimally invasive cardiac surgery, as a single dose provides a long period of myocardial protection. Despite widespread use in Europe, there is little data confirming its efficacy compared with conventional (blood or crystalloid) cardioplegia. There is similar enthusiasm for its use in organ preservation for transplant, but also a lack of data. This systematic review aimed to assess the evidence for the efficacy of Custodiol in myocardial protection and as a preservation solution in heart transplant.

METHODS

Electronic searches were performed of six databases from inception to October 2013. Reviewers independently identified studies that compared Custodiol with conventional cardioplegia (blood or extracellular crystalloid) in adult patients for meta-analysis; large case series that reported results using Custodiol were analyzed. Next, we identified studies that compared Custodiol with other organ preservation solutions for organ preservation in heart transplant.

RESULTS

Fourteen studies compared Custodiol with conventional cardioplegia for myocardial protection in adult cardiac surgery. No difference was identified in mortality; there was a trend for increased incidence of ventricular fibrillation in the Custodiol group that did not reach statistical significance. No difference was identified in studies that compared Custodiol with other solutions for heart transplant.

CONCLUSIONS

Despite widespread clinical use, the evidence supporting the superiority of Custodiol over other solutions for myocardial protection or organ preservation is limited. Large randomised trials are required.

The comparison of the effects of Bretschneider's histidine-tryptophan-ketoglutarate and conventional crystalloid cardioplegia on pediatric myocardium at tissue level

Cardioplegic arrest is one of the most common myocardial protection strategies. A wide variety of cardioplegic solutions are routinely being used. There is an ongoing discussion about the relative effectiveness of these solutions considering myocardial protection. This study aims to investigate the hypothesis that the use of histidine-tryptophan-ketoglutarate (HTK) cardioplegia leads to decreased ischemic damage on myocardium compared with the use of conventional crystalloid cardioplegia. The study population was 32 patients operated on at Başkent University, Department of Cardiovascular Surgery for congenital heart diseases. The first group of 16 patients received conventional crystalloid cardioplegia (KK group) which is a modification of St. Thomas' solution, while the second group of 16 patients received HTK solution (HTK group). The echocardiographic measurements and the laboratory values of the patients were taken as the clinical variables. Right ventricular biopsies were taken from every patient before and after cardioplegic arrest. These biopsies were histopathologically examined for apoptosis using caspase-3 antigen and cell proliferation using Ki-67 antigen. The statistical analysis revealed no significant difference between the two groups regarding the clinical variables, apoptotic indices and proliferation indices. The apoptotic indices in the postcardioplegic arrest biopsies positively correlated with aortic clamp time in the KK group but not in the HTK group. Liver function tests on postoperative day 1 positively correlated with aortic clamp time in both groups. On postoperative day 2, this correlation was sustained in the KK group and ceased in HTK group. The difference in the correlation of apoptotic indices and liver function tests between the groups is accepted as a supportive finding for HTK solution. However, it can be postulated that when the aortic clamp times are similar to those in the present study, the clinical manifestation of the difference between the two solutions would not be significant.

Which is the better option during neonatal cardiopulmonary bypass: HTK solution or cold blood cardioplegia?

The optimal myocardial protection strategy for newborns/infants undergoing congenital heart surgery remains controversial. The purpose of this study was to compare myocardial protection using histidine-tryptophan-ketoglutarate (HTK) and cold blood cardioplegia in a neonatal piglet model. Twenty-one piglets were randomized to three groups: the control group (C group, n = 7), a single dose of HTK group (H group, n = 7), and multidose cold blood cardioplegia group (B group, n = 7). Animals in the two experimental groups were placed on hypothermic cardiopulmonary bypass, after which the ascending aorta was clamped for 2 hours. Immediately after declamping, both the difference between arterial and coronary sinus blood lactate concentrations and the oxygen extraction did not differ between the H group and the B group. At 3 hours after declamping, rise in serum troponin-T and creatine kinase isoenzyme MB levels showed no significant differences between the H group and the B group (p = 0.735 and p = 0.103, respectively). No significant differences were noted in the myocardial lactate content, ATP content, and histopathological score between the H group and the B group (p = 0.810, p = 0.158, and p = 0.399, respectively). Transfusion requirement in the B group was significantly more than that in the H group (p = 0.003). HTK solution provides equivalent myocardial protection to multidose cold blood cardioplegia for the neonatal heart with less transfusion requirement.

Reno-protective effects of epigallocatechingallate in a small piglet model of extracorporeal circulation

Cardiopulmonary bypass still often is a necessary tool in cardiac surgery in particular in the correction of congenital heart defects in small infants. Nevertheless, among the complications linked to extracorporeal circulation (ECC) with cardiopulmonary bypass (CPB) in both infants and adults one of the most serious problems is renal impairment. Since this might be caused by ischemia/reperfusion injury and accumulation of free radicals, we used (-)-epigallocatechin-3-gallate (EGCG), a derivate from green tea, which is known to possess antioxidant, antiapoptotic and NO-scavenging properties in order to find out whether EGCG may protect the kidney. 23 four-week-old Angler Sattelschwein-piglets (8-15 kg) were divided into three groups: control-group (n=7), ECC-group (n=10), EGCG-group (n=6). The ECC- and EGCG-group were thoracotomized and underwent CPB for 120 min followed by a 90-min recovery-time. The EGCG-group received 10 mg/kg EGCG before and after CPB. Histology revealed that CPB led to widening of Bowman's capsule, and to vacuolization of proximal tubular cells (p<0.05) which could be prevented by EGCG (p<0.05). Using immunohistology, we found significant nuclear translocation of hypoxia-inducible-factor-1-alpha (HIF-1-alpha) and increased nitrotyrosine formation in the ECC-group. Both were significantly (p<0.05) inhibited by EGCG. ECC-induced loss of energy-rich phosphates was prevented by EGCG. In blood samples we found that CPB resulted in increases in creatinine and urea (in serum) and led to loss of total protein (p<0.05), which all was not present in EGCG-treated animals. We conclude that CPB causes damage in the kidney which can be attenuated by EGCG.