Custodiol versus blood cardioplegia in complex cardiac operations: an Australian experience

Del Nido cardioplegia in adult cardiac surgery: Clinical outcomes in a single center all-comer study

INTRODUCTION

The use of Del Nido Cardioplegia (DNC) has been extended in the latest years from pediatrics to adult cardiac surgery with encouraging results. We sought to investigate clinical and biochemical outcomes in adult patients who underwent cardiac surgery with different degrees of complexity who received DNC for myocardial protection.

METHODS

Data on one-thousand patients were retrospectively collected from 2020 to 2022. The only exclusion criteria was off-pump adult cardiac surgery. Surgical procedures weight was categorized according EuroSCORE II in six groups: Single-CABG(G1), isolated non-CABG(mitral) (G2), isolated non-CABG(aortic) (G3), isolated non-CABG(any) (G4), 2-procedures(G5), 3/more-procedures(G6). Primary endpoint was to identify a binomial correlation between hs-TnT/CK-MB and the cross-clamp time (X-Clamp). A secondary endpoint was the comparison between the treatment groups of the vasoactive-inotropic score (VIS) and the need of mechanical circulatory support (MCS).

RESULTS

A linear correlation was identified between hs-TnT and X-clamp in the overall population (rho:0.447, p< .001) and in the treatment groups (G1:rho=0.357, p< .001/G2:rho=0.455, p< .001/G3:rho=0.307, p= .001/G4:rho=0.165, p= .257/G5:rho=0.157, p= .031/G6:rho=0.226, p= .015). Similarly, a linear correlation between CK-MB and X-clamp in the overall population (rho=0.457, p< .001) and treatment group (G1:rho=0.282, p< .001/G2:rho=0.287, p= .025/G3:rho=0.211, p= .009/G4:rho=0.0878, p= .548/G5:rho=0.309, p< .001/G6: rho=0.212, p= .024) was identified. As regard for the secondary endpoint, no differences were reported between the treatment groups in terms of VIS and MCS (VIS G1:7; G2:4; G3:7; G4:7, G5:5.5, G6:6, p-value= .691) (MCS G1: 4.5%; G2:4.8%; G3:3.3%; G4:3.1%; G5:1.4%; G6:5.3%; p-value= .372).

CONCLUSIONS

Del Nido Cardioplegia is a safe and useful tool in adult cardiac surgery allowing operators to achieve a stable and durable cardioplegic arrest. Despite accounting with different types of surgery, the six subgroups of our study population showed similar perioperative results.

Blood versus crystalloid cardioplegia during triple valve surgery: A single center experience

BACKGROUND

The efficacy of different cardioplegia solutions on outcomes of complex cardiac operations such as triple valve surgery (TVS) is scarce. Here we compared the outcomes in TVS patients receiving either crystalloid (Bretschneider) or blood (Calafiore) cardioplegia.

METHODS

Screening of our institutional database with prospectively entered data identified 471 consecutive patients (mean age 70.3 ± 9.2 years; 50.9% male), who underwent TVS (replacement or repair of aortic, mitral and tricuspid valve) between December 1994 and January 2013. In 277 patients, cardiac arrest was induced with HTK-Bretschneider solution (HTK, n = 277, 58.8%), whereas 194 received cold blood cardioplegia (BCP) according to Calafiore (n = 194, 41.2%). Comparisons of perioperative and follow up outcomes were made between cardioplegia groups.

RESULTS

Preoperative patient characteristics and comorbidities were equally balanced between groups. 30-days mortality was similar between groups (HTK: 16.2%; BCP: 18.2%; p = 0.619). Incidence of the cumulative endpoint (30days mortality, myocardial infarction (MI), arrhythmia, low cardiac output syndrome or need for permanent pacemaker implantation) was also comparable (HTK: 47.6%; BCP: 54.8%, p = 0.149). In patients with reduced left ventricular ejection fraction (LVEF <40%), 30days mortality was higher in the HTK group (HTK 18/71 22.5%; BCP 5/50 10%; p = 0.037). Five-year survival was similar between groups (52 ± 6% for HTK and 55 ± 5% for BCP patients). In-Hospital mortality was best predicted by length of surgery and reperfusion ratio. Decreased age, shorter bypass time, preserved LVEF and concomitant surgical procedures have been found to be protective from long-term mortality.

CONCLUSIONS

Myocardial protection with HTK shows equivalent outcomes compared to BCP during TVS. Patients with reduced left ventricular function may benefit from BCP during TVS.

The Potential Neurological Impact of Intraoperative Hyponatremia Using Histidine-Tryptophan-Ketoglutarate Cardioplegia Infusion in Adult Cardiac Surgery

Background and Objectives: The relationship between histidine-tryptophan-ketoglutarate (HTK)-induced hyponatremia and brain injury in adult cardiac surgery patients is unclear. This study analyzed postoperative neurological outcomes after intraoperative HTK cardioplegia infusion. Materials and Methods: A prospective cohort study was conducted on 60 adult patients who underwent cardiac surgery with cardiopulmonary bypass. Of these patients, 13 and 47 received HTK infusion and conventional hyperkalemic cardioplegia, respectively. The patients' baseline characteristics, intraoperative data, brain injury markers, Mini-Mental State Examination (MMSE) scores, and quantitative electroencephalography (qEEG) data were collected. Electrolyte changes during cardiopulmonary bypass, the degree of hyponatremia, and any associated brain insults were evaluated. Results: The HTK group presented with acute hyponatremia during cardiopulmonary bypass, which was intraoperatively corrected through ultrafiltration and normal saline administration. Postoperative sodium levels were higher in the HTK group than in the conventional cardioplegia group. The change in neuron-specific enolase levels after cardiopulmonary bypass was significantly higher in the HTK group (p = 0.043). The changes showed no significant differences using case-control matching. qEEG analysis revealed a significant increase in relative delta power in the HTK group on postoperative day (POD) 7 (p = 0.018); however, no significant changes were noted on POD 60. The MMSE scores were not significantly different between the two groups on POD 7 and POD 60. Conclusions: HTK-induced acute hyponatremia and rapid correction with normal saline during adult cardiac surgeries were associated with a potential short-term but not long-term neurological impact. Further studies are required to determine the necessity of correction for HTK-induced hyponatremia.

Comparison of "Huaxi-1" or "histidine-tryptophan-ketoglutarate" cardioplegia in an animal model

Background

Using a pig model of cardiopulmonary bypass, we compared outcomes after cardioplegia either with our in-house "Huaxi-1" solution containing natural blood and crystalloid or with the entirely crystalloid, commercially available "histidine-tryptophan-ketoglutarate" solution.

Methods

Cardiopulmonary bypass was established in 12 healthy male pigs, who were randomized to receive a single dose of either Huaxi-1 or entirely crystalloid. All animals were then subjected to whole-heart ischemia for 90 min, followed by 2 h of reperfusion, after which myocardial injury was assessed in terms of cardiac function, myocardial pathology and levels of biomarkers in plasma, while levels of high-energy phosphate in myocardium were assayed using liquid chromatography.

Results

Animals given Huaxi-1 cardioplegia required significantly less time to be weaned off bypass, they received significantly lower doses of norepinephrine, and they showed significantly higher levels (mean ± SD) of adenosine triphosphate (14 ± 4 vs. 8 ± 2 µg/mg, P = 0.005), adenosine diphosphate (16 ± 2 vs. 13 ± 2 µg/mg, P = 0.046), and total adenine nucleotide (37 ± 4 vs. 30 ± 3 µg/mg, P = 0.006) in myocardium after 2 h of reperfusion. They also showed less severe bleeding, edema and injury to mitochondria and myofibers in myocardium. The two groups did not differ significantly in doses of inotropic drugs received, cardiac output or levels of biomarkers in plasma.

Conclusions

In this animal model of healthy hearts subjected to 90 min of ischemia, Huaxi-1 cardioplegia may be superior to entirely crystalloid cardioplegia for promoting energy generation and attenuating ischemia/reperfusion injury in myocardium.

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.

Upper Hemisternotomy Versus Full Sternotomy for Replacement of the Supracoronary Ascending Aorta and Aortic Valve

OBJECTIVE

Upper hemisternotomy (UHS) for supracoronary ascending aorta replacement (scAAR) with concomitant aortic valve replacement (AVR) results in less trauma and potentially faster convalescence compared with full sternotomy (FS). Direct head-to-head studies are lacking. We compared a group of UHS patients with a matched group of FS patients undergoing scAAR and AVR.

METHODS

There were 198 patients who underwent scAAR and AVR procedures by a single surgeon between 1999 and 2020. After matching 6 preoperative characteristics, there were 50 UHS and 50 FS patients. Patients who required acute type A aortic dissection repair, reoperations, concomitant procedures, or hypothermic circulatory arrest were excluded.

RESULTS

In the matched sample, the hospital mortality rate was 1% (1 of 100). The median cardiopulmonary bypass time was 150 (interquartile range [IQR], 131 to 172) min and 164.5 (IQR, 138 to 190) min, respectively, for the UHS and FS groups (P = 0.08). The median aortic cross-clamp time was 121 (IQR, 107 to 139) min during UHS and 131 (IQR, 115 to 159) min during FS (P = 0.05). The median ventilation time was 7 (IQR, 3 to 14) h versus 17 (IQR, 10 to 24) h, respectively, after UHS and FS (P = 0.005). The median hospital length of stay was 7 (IQR, 6 to 9) days after UHS and 8 (IQR, 7 to 11) days after FS (P = 0.05).

CONCLUSIONS

The low morbidity and mortality support the wider use of UHS for scAAR and AVR in appropriately selected patients. Larger studies are needed to confirm these initial findings.

Comparison of Cardioplegic Solutions in Coronary Bypass Surgery Over Autophagy and Apoptosis Mechanisms

BACKGROUND

Coronary artery disease (CAD) due to myocardial ischemia causes permanent loss of heart tissue.

OBJECTIVES

We aimed to demonstrate the possible damage to the myocardium at the molecular level through the mechanisms of autophagy and apoptosis in coronary bypass surgery patients.

METHODS

One group was administered a Custodiol cardioplegia solution, and the other group was administered a Blood cardioplegia solution. Two myocardial samples were collected from each patient during the operation, just before cardiac arrest and after the aortic cross-clamp was released. The expressions of autophagy and apoptosis markers were evaluated. The level of statistical significance adopted was 5%.

RESULTS

The expression of the BECLIN gene was significant in the myocardial tissues in the BC group (p=0.0078). CASPASE 3, 8, and 9 gene expression levels were significantly lower in the CC group. Postoperative TnT levels were significantly different between the groups (p=0.0072). CASPASE 8 and CASPASE 9 gene expressions were similar before and after aortic cross-clamping (p=0.8552, p=0.8891). In the CC group, CASPASE 3, CASPASE 8, and CASPASE 9 gene expression levels were not found to be significantly different in tissue samples taken after aortic cross-clamping (p=0.7354, p=0.0758, p=0.4128, respectively).

CONCLUSIONS

With our findings, we believe that CC and BC solutions do not have a significant difference in terms of myocardial protection during bypass operations.

Renal perfusion with histidine-tryptophan-ketoglutarate compared with Ringer's solution in patients undergoing thoracoabdominal aortic open repair

OBJECTIVE

The objective of this study was to compare the efficacy of renal perfusion with Custodiol (Dr Franz-Kohler Chemie GmbH, Bensheim, Germany) versus enriched Ringer's solution for renal protection in patients undergoing open thoracoabdominal aortic aneurysm (TAAA) repair.

METHODS

Ninety consecutive patients scheduled for elective open TAAA repair were enrolled between 2015 and 2017 in a single-center, phase IV, prospective, parallel, randomized, double-blind trial (the CUstodiol versus RInger: whaT Is the Best Agent [CURITIBA] trial), and randomized to renal arteries perfusion with 4°C Custodiol (Dr Franz-Kohler Chemie GmbH, Bensheim, Germany; n = 45) or 4°C lactated Ringer's solution (n = 45). The incidence of acute kidney injury (AKI) in patients undergoing TAAA open surgery using Custodiol renal perfusion versus an enriched Ringer's solution was the primary end point.

RESULTS

Ninety patients completed the study (45 patients in each group). The incidence of postoperative AKI was significantly lower in the Custodiol group (48.9% vs 75.6%; P = .02). In the multivariable model, only the use of Custodiol solution resulted as protective from the occurrence of any AKI (odds ratio, 0.230; 95% confidence interval, 0.086-0.614; P = .003), whereas TAAA type II extent was associated with the development of severe AKI (odds ratio, 4.277; 95% confidence interval, 1.239-14.762; P = .02). At 1-year follow-up, serum creatinine was not significantly different from the preoperative values in both groups.

CONCLUSIONS

The use of Custodiol during open TAAA repair was safe and resulted in significantly lower rates of postoperative AKI compared with Ringer's solution. These findings support safety and efficacy of Custodiol in this specific setting, which is currently off-label.

An infant with suspected missed diagnosis of Williams syndrome failed weaning off CPB after surgical correction of pulmonary stenosis: a case report and literature review

Williams syndrome (WS) is a rare congenital developmental disorder caused by the deletion of between 26 and 28 genes on chromosome 7q11.23. For patients with WS, in view of the particularity of the supravalvular aortic stenosis, choosing appropriate arterial cannula, maintaining higher perfusion pressure as well as strengthening myocardial protection during cardiopulmonary bypass (CPB) is essential to the clinical outcome. Here, we report a child with pulmonary artery valvular stenosis who failed to wean off CPB because of malignant arrhythmias and cardiac insufficiency after surgical correction of pulmonary valvular stenosis. With the assistance of extracorporeal membrane oxygenation (ECMO), emergency cardiac catheterization revealed supravalvular aortic stenosis (SVAS), which suggests a suspected missed diagnosis of WS. Finally, under the support of ECMO, the cardiac function gradually returned to normal, and the child was discharged 23 days after surgery.

Sellke F, Feng J. Potassium and Cardiac Surgery

Potassium homeostasis affects cardiac rhythm and contractility, along with vascular reactivity and vascular smooth muscle proliferation. This chapter will focus on potassium dynamics during and after cardiac surgery involving cardioplegic arrest and cardiopulmonary bypass (CPB). Hyperkalemic, hypothermic solutions are frequently used to induce cardioplegic arrest and protect the heart during cardiac surgery involving CPB. Common consequences of hyperkalemic cardioplegic arrest and reperfusion include microvascular dysfunction involving several organ systems and myocardial dysfunction. Immediately after CPB, blood potassium levels often drop precipitously due to a variety of factors, including CPB -induced electrolyte depletion and frequent, long-term administration of insulin during and after surgery. Meanwhile, some patients with pre-existing kidney dysfunction may experience postoperative hyperkalemia following cardioplegia. Any degree of postoperative hyper/hypokalemia significantly elevates the risk of cardiac arrythmias and subsequent myocardial failure. Therefore, proper management of blood potassium levels during and after cardioplegia/CPB is crucial for optimizing patient outcomes following cardiac 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.

Blood mRNA Expression Profiles of Autophagy, Apoptosis, and Hypoxia Markers on Blood Cardioplegia and Custodiol Cardioplegia Groups

Introduction:

Blood cardioplegia (BC) and Custodiol cardioplegia (CC) have been used for a long time in open heart surgery and are highly effective solutions. The most controversial issue among these two is whether there is any difference between them regarding myocardial damage after ischemia surgery. In this study, autophagy, apoptosis, and hypoxia markers were investigated and that way we evaluated the differences between BC and CC patients.

Methods:

A total of 30 patients were included in this study, using two different cardioplegic solutions. Three different whole blood samples of the patients were taken from a central vein (preoperatively, immediately postoperatively, and one day after surgery). Total ribonucleic acid was extracted from these samples. Quantitative real-time polymerase chain reaction was performed, and changes in gene expression were determined by the 2-∆∆Ct method of relative quantification.

Results:

In the CC group, Beclin gene expression level was found to be higher and this difference was statistically significant (P=0.0024). Similarly, cysteine-aspartic acid protease (caspase) 9 and hypoxia-inducible factor 1α messenger ribonucleic acid (mRNA) gene expression level increased and were significantly different in the CC group. In the BC group, Beclin and microtubule-associated protein light chain 3 expressions were higher in the samples taken one day after surgery. Caspases 3 and 8 gene expressions were significantly different in the BC group.

Conclusion:

As a result of the analysis performed between the two cardioplegia groups, it has been shown that CC harms the myocardium more than BC at the level of mRNA expression of related markers.

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.

Single-center experience and evolution of technique with the E-vita Open prosthesis

BACKGROUND

We report our experience in aortic arch repair with the E-vita Open hybrid prosthesis and describe the changes in our technique over time.

METHODS

Between October 2013 and December 2019, 56 patients underwent a total aortic arch replacement with the E-vita Open hybrid prosthesis. The main indications were thoracic aorta aneurysm (n = 27) and acute type A aortic dissection (n = 18). We analyze the technique and results in the overall series, and compare both between our early (group I, 25 patients) and late experience (group II, 31 patients).

RESULTS

Overall in-hospital mortality was 7.1% (n = 4), and permanent stroke and spinal cord injury were 3.6% and 1.8%, respectively. Fifteen patients (26.8%) underwent a planned second procedure on the distal aorta: 13 endovascular, 1 open, and 1 hybrid. Survival at 1 and 3 years was 90.7% and 80.7%, respectively. Group II included more patients with acute dissection (45.2% vs 16%, P = .02), higher rates of bilateral cerebral perfusion (100% vs 64%, P < .001), left subclavian artery perfusion during lower body circulatory arrest (87.1% vs 0%, P < .001), early reperfusion (96.8% vs 40%, P < .001), and zone 0 to 2 distal anastomosis (100% vs 72%, P = .02). In-hospital mortality (3.2% vs 12%) and permanent stroke (0% vs 8%) tended to be lower in group II.

CONCLUSIONS

Total arch replacement with E-vita Open hybrid prosthesis in complex thoracic aorta disease is safe. One-stage treatment is feasible when pathology does not extend beyond the proximal descending thoracic aorta. In any case, it facilitates subsequent procedures on distal aorta if needed.

Safety of Custodiol cardioplegia: a cohort study in patients undergoing cardiac surgery with elongated aortic cross-clamp time

BACKGROUND/OBJECTIVES

The increasing complexity of patients undergoing cardiac surgery requires extended myocardial ischaemic periods. Cardiac surgeons demand a cardioplegic solution with prolonged myocardial protection. Therefore, we introduced Custodiol in our centre in 2011. The aim of this study was to investigate the safety and efficacy of Custodiol compared with the standard method of cardioplegia.

METHODS

Between 2011 and 2016, 188 adult patients who underwent mitral valve surgery combined with coronary artery bypass grafting were included in this retrospective study. In 113 patients, Custodiol cardioplegia was used to achieve cardiac arrest, while St. Thomas Hospital solution was used in 75 patients. The primary endpoint of the study was the degree myocardial damage which was estimated by the measurement of creatine kinase-myocardial band on the first postoperative day. A linear regression analysis was performed to compare the aortic cross-clamp time with the postoperative myocardial damage in both groups.

RESULTS

The extracorporeal circulation time and aortic cross-clamp were significantly longer in the Custodiol group than in the St. Thomas group: 125.6 ± 32.5 minutes versus 93.1 ± 27.7 minutes (p < 0.001), respectively. However, there was no significant difference between the two groups regarding the postoperative levels of creatine kinase-myocardial band (96 (70-140) U/L vs. 86 (69-120) U/L, respectively; p = 0.321). There was no significant differences between the two groups regarding the 30-day mortality (6.1% vs. 5.5%, respectively; p = 1.000) or 120-day mortality (9.6% vs. 11.0%, respectively; p = 0.806).

CONCLUSION

Our findings demonstrate that Custodiol is a safe method of myocardial protection for patients who underwent mitral valve surgery with coronary artery bypass grafting in our hospital. Further investigations extended to more cardiac surgery populations are needed to confirm clinical benefits of Custodiol cardioplegia.

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.

Effects of histidine load on ammonia, amino acid, and adenine nucleotide concentrations in rats

The unique capability of proton buffering is the rationale for using histidine (HIS) as a component of solutions for induction of cardiac arrest and myocardial protection in cardiac surgery. In humans, infusion of cardioplegic solution may increase blood plasma HIS from ~ 70 to ~ 21,000 µM. We examined the effects of a large intravenous dose of HIS on ammonia and amino acid concentrations and energy status of the body. Rats received 198 mM HIS intravenously (20 ml/kg) or vehicle. Samples of blood plasma, urine, liver, and soleus (SOL) and extensor digitorum longus (EDL) muscles were analysed at 2 or 24 h after treatment. At 2 h after HIS load, we found higher HIS concentration in all examined tissues, higher urea and ammonia concentrations in blood and urine, lower ATP content and higher AMP/ATP ratio in the liver and muscles, higher concentrations of almost all examined amino acids in urine, and lower glycine concentration in blood plasma, liver, and muscles when compared with controls. Changes in other amino acids were tissue dependent, markedly increased alanine and glutamate in the blood and the liver. At 24 h, the main findings were lower ATP concentrations in muscles, lower concentrations of branched-chain amino acids (BCAA; valine, leucine, and isoleucine) in blood plasma and muscles, and higher carnosine content in SOL when compared with controls. It is concluded that a load of large HIS dose results in increased ammonia levels and marked alterations in amino acid and energy metabolism. Pathogenesis is discussed in the article.

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.

Novel application of amino-acid buffered solution for neuroprotection against ischemia/reperfusion injury

Ischemic neuron loss contributes to brain dysfunction in patients with cardiac arrest (CA). Histidine–tryptophan–ketoglutarate (HTK) solution is a preservative used during organ transplantation. We tested the potential of HTK to protect neurons from severe hypoxia (SH) following CA. We isolated rat primary cortical neurons and induced SH with or without HTK. Changes in caspase-3, hypoxia-inducible factor 1-alpha (HIF-1α), and nicotinamide adenine dinucleotide phosphate oxidase-4 (NOX4) expression were evaluated at different time points up to 72 h. Using a rat asphyxia model, we induced CA-mediated brain damage and then completed resuscitation. HTK or sterile saline was administered into the left carotid artery. Neurological deficit scoring and mortality were evaluated for 3 days. Then the rats were sacrificed for evaluation of NOX4 and H₂O₂ levels in blood and brain. In the in vitro study, HTK attenuated SH- and H₂O₂-mediated cytotoxicity in a volume- and time-dependent manner, associated with persistent HIF-1α expression and reductions in procaspase-3 activation and NOX4 expression. The inhibition of HIF-1α abrogated HTK’s effect on NOX4. In the in vivo study, neurological scores were significantly improved by HTK. H₂O₂ level, NOX4 activity, and NOX4 gene expression were all decreased in the brain specimens of HTK-treated rats. Our results suggest that HTK acts as an effective neuroprotective solution by maintaining elevated HIF-1α level, which was associated with inhibited procaspase-3 activation and decreased NOX4 expression.

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.

Single-Shot Cold Histidine-Tryptophan-Ketoglutarate Cardioplegia for Long Aortic Cross-Clamping Durations in Neonates

OBJECTIVE

More than 30% of European pediatric cardiac surgery centers use single-dose cold histidine-tryptophan-ketoglutarate cardioplegia (Custodiol; Dr Franz Köhler Chemie GmbH, Bensheim, Germany). In neonates with transposition of the great arteries, arterial switch surgery (ASO) implies aortic division, and it is unknown whether repeated ostial cannulation causes intimal insult and affects long-term results, and therefore, single-dose Custodiol is appealing. The present study investigated the association among myocardial no-flow duration, postoperative troponins, and postoperative outcomes in neonates undergoing ASO with Custodiol cardioplegia.

DESIGN

Retrospective analysis of the association among myocardial no-flow duration, postoperative troponin release (concentration magnitude × measurement duration within 48 h), and outcomes using stratification according to coronary anatomy and attending surgeon.

SETTING

Single-institutional, tertiary pediatric cardiac surgery unit of a university hospital.

PARTICIPANTS

The study comprised 101 neonates undergoing ASO.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The mean age of patients was 6.1 ± 5.4 days, the cardiopulmonary bypass duration was 108.7 ± 54.1 minutes, the temperature during cross-clamping was 31.1°C ± 1.7°C, the duration of mechanical ventilation was 4 (3-6) days, the length of intensive care unit stay was 7 (5-8) days, delayed sternal closure occurred in 32 (31.7%) patients, and no patients died. The myocardial no-flow duration averaged 62.3 ± 14.6 minutes and was linked with both troponin release (p = 0.04) and low cardiac output syndrome, as assessed by the requirement for delayed sternal closure (p = 0.03), regardless of cardiopulmonary bypass duration and temperature. Eighty-two percent of the patients with myocardial no-flow duration >74 minutes necessitated delayed sternal closure.

CONCLUSIONS

Single-dose Custodiol may be inadequate for prolonged cross-clamping durations without myocardial perfusion in neonates.

Comparative Analysis of Myocardial Protection with HTK Solution and Hypothermic Hyperkalemic Blood Solution in the Correction of Acyanogenic Congenital Cardiopathies - A Randomized Study

OBJECTIVE

The goal of the present study was to compare the myocardial protection obtained with histidine-tryptophan-ketoglutarate (HTK) cardioplegic solution (Custodiol®) and with intermittent hypothermic blood solution.

METHODS

Two homogenous groups of 25 children with acyanotic congenital heart disease who underwent total correction with mean aortic clamping time of 60 minutes were evaluated in this randomized study. Troponin and creatine kinase-MB curves, vasoactive-inotropic score, and left ventricular function were obtained by echocardiogram in each group. The values were correlated and presented through graphs and tables after adequate statistical treatment.

RESULTS

It was observed that values of all the studied variables varied over time, but there was no difference between the groups.

CONCLUSION

We conclude that in patients with acyanotic congenital cardiopathies submitted to total surgical correction, mean aortic clamping time around one hour, and cardiopulmonary bypass with moderate hypothermia, the HTK crystalloid cardioplegic solution offers the same myocardial protection as the cold-blood hyperkalemic cardioplegic solution analyzed, according to the variables considered in our study model.

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.

Routine use of bilateral internal thoracic artery grafting in women does not increase in-hospital mortality and could improve long-term survival

BACKGROUND

Bilateral internal thoracic artery (BITA) grafting is underused in women.

METHODS

Outcomes of 798 consecutive women with multivessel coronary disease who underwent isolated coronary surgery (1999-2016) using BITA (n=530, 66.4%) or single internal thoracic artery (SITA) grafting (n=268, 33.6%) were reviewed retrospectively. Differences between BITA and SITA cohort were adjusted by propensity score matching. For both series, late survival was estimated with the Kaplan-Meier method.

RESULTS

One-to-one propensity score matching resulted in 247 BITA/SITA pairs with similar baseline characteristics and risk profile. According to the propensity matching, BITA grafting was associated with a trend towards reduced in-hospital mortality (3.2% vs. 5.7%, p=0.19). However, BITA women had an increased chest tube output (p=0.0076) as well as higher rates of any (13% vs. 5.3%, p=0.003) and deep sternal wound infections (9.3% vs. 4.9%, p=0.054), this translating in a longer in-hospital stay (10 vs. 9days, p=0.029). Test for interaction showed that body mass index >30kg/m² and extracardiac arteriopathy were associated with a higher risk of deep sternal wound infection in BITA than in SITA women (23.4% vs. 13.7%, p<0.001 and 23.9% vs. 3.4%, p=0.001, respectively). Freedom from all-cause death and cardiac or cerebrovascular death were improved in BITA cohort, even though the differences were not quite significant (p=0.16 and 0.076, respectively).

CONCLUSIONS

When routinely performed, BITA grafting does not increase in-hospital mortality in women and could improve long-term survival. However, its use should be avoided in obese women with extracardiac arteriopathy because of increased risk of deep sternal wound infection.

Bretschneider solution-induced alterations in the urine metabolome in cardiac surgery patients

The development of Bretschneider’s histidine-tryptophan-ketoglutarate (HTK) cardioplegia solution represented a major advancement in cardiac surgery, offering significant myocardial protection. However, metabolic changes induced by this additive in the whole body have not been systematically investigated. Using an untargeted mass spectrometry-based method to deeply explore the urine metabolome, we sought to provide a holistic and systematic view of metabolic perturbations occurred in patients receiving HTK. Prospective urine samples were collected from 100 patients who had undergone cardiac surgery, and metabolomic changes were profiled using a high-performance chemical isotope labeling liquid chromatography-mass spectrometry (LC-MS) method. A total of 14,642 peak pairs or metabolites were quantified using differential ¹³C-/¹²C-dansyl labeling LC-MS, which targets the amine/phenol submetabolome from urine specimens. We identified 223 metabolites that showed significant concentration change (fold change > 5) and assembled several potential metabolic pathway maps derived from these dysregulated metabolites. Our data indicated upregulated histidine metabolism with subsequently increased glutamine/glutamate metabolism, altered purine and pyrimidine metabolism, and enhanced vitamin B₆ metabolism in patients receiving HTK. Our findings provide solid evidence that HTK solution causes significant perturbations in several metabolic pathways and establish a basis for further study of key mechanisms underlying its organ-protective or potential harmful effects.

Lung Protection Strategies during Cardiopulmonary Bypass Affect the Composition of Blood Electrolytes and Metabolites-A Randomized Controlled Trial

Cardiac surgery with cardiopulmonary bypass (CPB) causes an acute lung ischemia-reperfusion injury, which can develop to pulmonary dysfunction postoperatively. This sub-study of the Pulmonary Protection Trial aimed to elucidate changes in arterial blood gas analyses, inflammatory protein interleukin-6, and metabolites of 90 chronic obstructive pulmonary disease patients following two lung protective regimens of pulmonary artery perfusion with either hypothermic histidine-tryptophan-ketoglutarate (HTK) solution or normothermic oxygenated blood during CPB, compared to the standard CPB with no pulmonary perfusion. Blood was collected at six time points before, during, and up to 20 h post-CPB. Blood gas analysis, enzyme-linked immunosorbent assay, and nuclear magnetic resonance spectroscopy were used, and multivariate and univariate statistical analyses were performed. All patients had decreased gas exchange, augmented inflammation, and metabolite alteration during and after CPB. While no difference was observed between patients receiving oxygenated blood and standard CPB, patients receiving HTK solution had an excess of metabolites involved in energy production and detoxification of reactive oxygen species. Also, patients receiving HTK suffered a transient isotonic hyponatremia that resolved within 20 h post-CPB. Additional studies are needed to further elucidate how to diminish lung ischemia-reperfusion injury during CPB, and thereby, reduce the risk of developing severe postoperative pulmonary dysfunction.

The Risk of Neurological Dysfunctions after Deep Hypothermic Circulatory Arrest with Retrograde Cerebral Perfusion

OBJECTIVE

Retrograde cerebral perfusion (RCP) is a brain protection technique that is adopted generally for anticipated short periods of deep hypothermic circulatory arrest (DHCA). However, the real impact of this technique on cerebral protection during DHCA remains a controversial issue.

METHODS

For 344 (59.5%) of 578 consecutive patients (mean age, 66.9 ± 10.9 years) who underwent cardiovascular surgery under DHCA at the present authors' institution (1999-2015), RCP was the sole technique of cerebral protection that was adopted in addition to deep hypothermia. Surgery of the thoracic aorta was performed in 95.9% of these RCP patients; in 92 cases there was an aortic arch involvement. Outcomes were reviewed retrospectively. The focus was on postoperative neurological dysfunctions.

RESULTS

There were 33 (9.6%) in-hospital deaths. Thirty-one (9%) patients had permanent neurological dysfunctions and 66 (19.1%) transitory neurological dysfunctions alone. Age older than 74 years (odds ratio [OR], 1.88, P = .023), surgery for acute aortic dissection (OR, 2.57; P = .0009), and DHCA time longer than 25 minutes (OR, 2.44; P = .0021) were predictors of neurological dysfunctions. The 10-year nonparametric estimate of freedom from all-cause death was 61.8% (95% confidence interval, 57.8%-65.8%). Permanent postoperative neurological dysfunctions were risk factors for cardiac or cerebrovascular death (hazard ratio, 2.6; P = .039) even after an adjusted survival analysis (P < .04).

CONCLUSIONS

According to the study findings, RCP, in addition to deep hypothermia, combines with a low risk of neurological dysfunctions provided that DHCA length is 25 minutes or less. Permanent postoperative neurological dysfunctions are predictors of poor late survival.

Clinical comparative analysis of histidine-tryptophan-ketoglutarate solution and St. Thomas crystalloid cardioplegia: A 12-year study from a single institution

Cardioplegic reperfusion during a long-term ischemic period interrupts cardiac surgery and increases cellular edema due to repeated administration. The present clinical study compared the protective effects of histidine-ketoglutarate-tryptophan (HTK) solution and St. Thomas crystalloid cardioplegia. Clinical experiences of the myocardial protection induced by one single perfusion with HTK were reviewed in high-risk patients with severe pulmonary arterial hypertension associated with complex congenital heart disease. This retrospective study included 88 high-risk patients (aortic cross-clamp time, >120 min) between March 2001 and July 2012. The cohort was divided into two groups according to the technique used. Either myocardial protection was performed with one single perfusion with HTK solution (HTK group) or with conventional St. Thomas crystalloid cardioplegia (St group). The duration of cardiopulmonary bypass did not differ between the two groups. The mortality, morbidity, intensive care unit (ICU) stay, postoperative hospitalization, and transfusions of HTK group are significantly lower than those of the St group (P<0.05). Univariate and multivariate analysis demonstrated that HTK is a statistically significant independent predictor of decreased early mortality and morbidity (P<0.05). In conclusion, the present findings suggested that HTK solution decreases mortality, morbidity, ICU stay, postoperative hospitalization, and transfusions in high-risk patients with severe pulmonary arterial hypertension associated with complex congenital heart disease.

Is cold blood cardioplegia absolutely superior to cold crystalloid cardioplegia in aortic valve surgery?

BACKGROUND

Experimental evidence suggests that blood cardioplegia (BCP) may be superior to cold crystalloid cardioplegia (CCP) for myocardial protection. However, robust clinical data are lacking. We compared postoperative outcome of patients undergoing aortic valve replacement (AVR) using cold anterograde-retrograde intermittent BCP versus anterograde (CCP).

METHODS

Adult consecutive isolated AVR performed between April 2006 and February 2011 at the Royal Infirmary Hospital of Edinburgh were retrospectively analyzed. The use of anterograde CCP was compared with that of intermittent anterograde-retrograde cold BCP. End points were intra-operative mortality, 30-day hospital re-admission, need for RBC or platelet transfusion, mechanical ventilation time and renal failure.

RESULTS

Of total 774 cases analyzed, 592 cases of BCP and 182 cases of CCP were identified. Demographics did not differ between groups (mean age: 67±12 years in CCP and 69±12 years in BCP). Groups (BCP vs. CCP) were indistinguishable (P>0.05, not significant) based on: average aortic cross clamp time 77.01±14.47 vs. 75.78±18.78 minutes, cardiopulmonary bypass time 104.07±43.70 vs. 100.34±25.90 minutes, surgery time 190.53±61.80 vs. 204.04±51.09 minutes and postoperative total blood consumption 1.38±2.11 vs. 1.61±2.4 units. The percentage of patients who required platelets' transfusion was similar: 12.8% BCP and 18.7% CCP (Fisher's exact test, P=0.053). Prevalence of respiratory failure was lower in BCP than in CCP: 2.6% vs. 6.3% (P=0.028). Admission time (days) at ICU was 3.63± 21.90 in BCP and 3.07±8.04 in CCP (not significant). Intra-hospital mortality, 30-day hospital re-admission, renal failure, sepsis, wound healing and stroke did not differ between groups.

CONCLUSIONS

BCP was strictly not superior to CCP in every aspect. In particular it was definitely not superior in terms of postoperative ventricular function. Our results question the absolute superiority of BCP over CCP in terms of hard outcomes. Likelihood of serious complications should be considered to improve risk profile of patients before choosing a cardioplegic solution.

Clinical Assessment of Histidine-Tryptophan-Ketoglutarate Solution and Modified St. Thomas' Solution in Pediatric Cardiac Surgery of Tetralogy of Fallot

The objective of this study is to compare the myocardium protective effect of Bretschneider's histidine-tryptophan-ketoglutarate (HTK) solution versus Modified St. Thomas' (STH) solution in pediatric cardiac surgery of Tetralogy of Fallot (TOF). Seventy-seven pediatric patients of TOF who received the total surgical repair were reviewed, from January 2014 to October 2015. A horizontal comparison between HTK solution and modified STH solution has been made since the HTK solutions were started to be used in our hospital. The patients were divided into the HTK group (n = 35) and the STH group (n = 33). The perioperative values of the groups were assessed in this study. The primary endpoints including spontaneous cardiac re-beating time, intensive care unit (ICU) stay, overall stay, mechanical ventilation postoperation, postoperation stay, overall stay, and perioperative echocardiographic results were analyzed in this study. We found that spontaneous cardiac re-beating time of the HTK group was significantly shorter than that of the STH group (0.26 min ± 0.56 vs. 1.33 ± 1.02, P < 0.001). There were no significant differences between the two groups in ICU stay (P = 0.29), postoperative mechanical ventilation time (P = 0.84), overall stay (0.73); and the mortalities of the two groups were similar (2.9 vs. 3.0%). Aimed at pediatric cardiac surgery of TOF, this study suggests that with similar aorta cross-clamping time, modified STH solution is as safe as HTK solution.

Histidine-tryptophan-ketoglutarate solution decreases mortality and morbidity in high-risk patients with severe pulmonary arterial hypertension associated with complex congenital heart disease: an 11-year experience from a single institution

Cardioplegic reperfusion during a long term ischemic period interrupts cardiac surgery and also increases cellular edema due to repeated solution administration. We reviewed the clinical experiences on myocardial protection of a single perfusion with histidine-tryptophan-ketoglutarate (HTK) for high-risk patients with severe pulmonary arterial hypertension associated with complex congenital heart disease. This retrospective study included 101 high-risk patients undergoing arterial switch operation between March 2001 and July 2012. We divided the cohort into two groups: HTK group, myocardial protection was carried out with one single perfusion with HTK solution; and St group, myocardial protection with conventional St. Thomas' crystalloid cardioplegic solution. The duration of cardiopulmonary bypass did not differ between the two groups. The mortality, morbidity, ICU stay, post-operative hospitalization time, and number of transfusions in HTK group were lower than those in St group (P<0.05). Univariate and multivariate analysis showed that HTK is a statistically significant independent predictor of decreased early mortality and morbidity (P<0.05). In conclusion, HTK solution seems to be an effective and safe alternative to St. Thomas' solution for cardioplegic reperfusion in high-risk patients with complex congenital heart disease.

The Impact of Diabetes on Early Outcomes after Routine Bilateral Internal Thoracic Artery Grafting

BACKGROUND

Increased risk of postoperative complications limits use of bilateral internal thoracic artery (BITA) grafting in diabetic patients. The authors' experience in routine BITA grafting was reviewed to investigate the impact of diabetes on early outcomes.

METHODS

Among the 4508 consecutive patients with multivessel coronary artery disease who underwent isolated coronary bypass surgery from January 1999 throughout August 2015, skeletonised BITA grafts were used in 3228 (71.6%) patients, 972 diabetic and 2256 non-diabetic. After one-to-one propensity score (PS)-matched analysis, 819 pairs of diabetic/non-diabetic patients were compared for postoperative outcomes. The operative risk was calculated for each patient according to the European System for Cardiac Operative Risk Evaluation II (EuroSCORE II).

RESULTS

Although diabetic had higher risk profiles than non-diabetic patients both in unmatched (EuroSCORE II: 5.3±7.3% vs. 3±4.2%, p<0.0001) and PS-matched series (EuroSCORE II: 5.1±7.1% vs. 3.6±4.3%, p<0.0001), there were no differences in hospital mortality (2.2% vs. 1.8%, p=0.52 and 2.1% vs. 2.3%, p=0.74, respectively). In PS-matched pairs, the use of adrenergic agonists (p=0.03), postoperative bleeding (p=0.0055) and deep incisional sternal wound infection (p=0.0018) were more frequent in diabetic patients who had a mean of longer hospital stays (p=0.023).

CONCLUSIONS

Bilateral internal thoracic artery grafting may be routinely performed even in diabetic patients despite higher risk profiles. Increased postoperative complications prolong hospital stay but do not impact on early mortality.

Predictors of immediate and long-term outcomes of coronary bypass surgery in patients with left ventricular dysfunction

Despite encouraging improvements, outcomes of coronary artery bypass grafting (CABG) in the presence of left ventricular (LV) dysfunction remain poor. In the present study, the authors' experience on this subject was reviewed to establish the predictors of immediate and long-term results of surgery. Out of 4383 consecutive patients with multivessel coronary artery disease who underwent primary isolated CABG at the authors' institution from January 1999 throughout September 2014, 300 patients (mean age 66.1 ± 9.6 years) suffered preoperatively from LV dysfunction (defined as LV ejection fraction ≤35 %). The mean expected operative risk (EuroSCORE II) was 10.3 ± 13 %. Hospital deaths and perioperative complications were analyzed retrospectively. Outcomes were evaluated during a mean follow-up of 6.2 ± 4 years. None, one or both internal thoracic arteries (ITAs) were used in 6.3, 29 and 64.7 % of cases, respectively. There were 16 (5.3 %) hospital deaths. Prolonged invasive ventilation (17.7 %), acute kidney injury (14.7 %) and multiple blood transfusion (21.3 %) were the most frequent major postoperative complications. The 10-year non-parametric estimates of freedom from all-cause death, cardiac death, and major adverse cardiac and cerebrovascular events (MACCEs) were 47.8 [95 % confidence interval (CI) 44.1-51.5], 65.3 (95 % CI 61.4-69.2), and 42.3 % (95 % CI 38.3-46.3), respectively. Shared predictors of decreased late survival and MACCEs were old age (P < 0.04), chronic lung disease (P < 0.01), chronic dialysis (P < 0.0001) and extracardiac arteriopathy (P < 0.045). After adjustment for corresponding risk factors, freedom from cardiac death was higher when both ITAs were used but only for patients with significant increase of LV ejection fraction early after surgery (P = 0.04). In patients with LV dysfunction, CABG may be performed with acceptable hospital mortality and long-term survival. Late outcomes depend mainly on preoperative characteristics of the patients. The use of both ITAs for myocardial revascularization may give long-term survival benefits but only for patients whose LV function improves significantly early after surgery.

Evidence-based medicine and myocardial protection — where is the evidence?

Objective:

Myocardial protection with cardioplegia is an integral component of most cardiac surgical procedures, providing protection of the heart by limiting metabolic activity and increasing the myocardium’s capacity to withstand ischemia for prolonged periods of time. Cardioplegia has greatly affected the landscape of cardiothoracic surgery since its introduction in the 1960s, but, to this day, there continues to be a debate over what the ideal cardioplegic solution should be. The goal of this analysis is to describe current practices in cardioplegia and to point out the lack of quality human research and subsequent publications that prevent best practices from being utilized.

Methods:

This study is a systematic review of journal publications pertaining to the composition of commonly used cardioplegic solutions. Four main types of cardioplegia were assessed to give a narrower field of examination; specifically, microplegia, del Nido, Custodiol HTK, and 4:1 blood cardioplegia. Other combinations of cardioplegia, including St. Thomas’s Solution and the University of Wisconsin (UW) Solution, were considered when applicable according to the context of the publication being reviewed. Factors being assessed consisted of scientific validity, nature of the test subject (isolated organ vs. animal vs. human studies), experimental setup (retrospective trials vs. randomized clinical trials) and patient outcomes.

Results:

There are very few randomized clinical trials with human subjects comparing commonly used cardioplegic solutions. Numerous retrospective studies exist, but often show similar intraoperative and postoperative outcomes between the solutions. Some solutions, del Nido cardioplegia in particular, were found to have few or no significant human trials to back the rigor required in such a highly specialized field as cardiovascular surgery. A wide variation in the types of surgeries and primary outcomes were included in the publications, so it is difficult to perform an accurate systematic review of the topic.

Conclusion:

Uniform variables among different studies would be preferable for analysis of this topic; thus, it is the researchers’ recommendation that the collection of multicenter data be undertaken in order to more fully answer this research question. Comparative effectiveness studies to associate commonly used solutions are needed. Without this research, surgeon preference remains the primary determining factor for deciding which cardioplegic solution to use. Cardioplegia selection should rely more on higher scientific research, using evidenced-based medicine and ranking of clinical studies.

Perfusion techniques for minimally invasive valve procedures

In this paper, we present, in detail, the simplified perfusion technique that we have adopted since January 2009 and that we have utilized in 200 cases for cardiac minimally invasive valvular procedures that were performed through a right lateral mini-thoracotomy in the 3(rd)-4(th) intercostal space. Cardiopulmonary bypass was achieved by means of the direct cannulation of the ascending aorta and the insertion of a percutaneous venous cannula in the femoral vein. A flexible aortic cross-clamp was applied through the skin incision and cardioplegic arrest was obtained with the antegrade delivery of a crystalloid solution. Gravity drainage was enhanced by vacuum-assisted aspiration. There were no technical complications related to this perfusion technique that we have adopted in minimally invasive surgical procedures.

Development of cardioplegic solution without potassium: experimental study in rat

Introduction

Myocardial preservation during open heart surgeries and harvesting for transplant are of great importance. The heart at the end of procedure has to resume its functions as soon as possible. All cardioplegic solutions are based on potassium for induction of cardioplegic arrest.

Objective

To assess a cardioplegic solution with no potassium addition to the formula with two other commercially available cardioplegic solutions. The comparative assessment was based on cytotoxicity, adenosine triphosphate myocardial preservation, and caspase 3 activity. The tested solution (LIRM) uses low doses of sodium channel blocker (lidocaine), potassium channel opener (cromakalin), and actin/myosin cross bridge inhibitor (2,3-butanedione monoxime).

Methods

Wistar rats underwent thoracotomy under mechanical ventilation and three different solutions were used for "in situ" perfusion for cardioplegic arrest induction: Custodiol (HTK), Braile (G/A), and LIRM solutions. After cardiac arrest, the hearts were excised and kept in cold storage for 4 hours. After this period, the hearts were assessed with optical light microscopy, myocardial ATP content and caspase 3 activity. All three solutions were evaluated for direct cytotoxicity with L929 and WEHI-164 cells.

Results

The ATP content was higher in the Custodiol group compared to two other solutions (P<0.05). The caspase activity was lower in the HTK group compared to LIRM and G/A solutions (P<0.01). The LIRM solution showed lower caspase activity compared to Braile solution (P<0.01). All solutions showed no cytotoxicity effect after 24 hours of cells exposure to cardioplegic solutions.

Conclusion

Cardioplegia solutions without potassium are promised and aminoacid addition might be an interesting strategy. More evaluation is necessary for an optimal cardioplegic solution development.

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.