Cardioplegia Delivery Research Articles

International Pediatric Perfusion Practice: 2016 Survey Results.

New cardiopulmonary bypass device techniques emerge and are reported in the scientific literature. The extent to which they are actually adopted into clinical practice is not well known. Since 1989, we have periodically surveyed pediatric cardiac centers to ascertain practice patterns. In December 2016, a 186-question perfusion survey was distributed to pediatric cardiac surgery centers all over the world using a Web-based survey tool. Responses were received from 93 North American (NA) centers (the United States and Canada) and 67 non-NA (NNA) centers, representing 19,645 cumulative annual procedures in NA and 27,776 in NNA centers on patients <18 years. Wide variation in practice was evident across geographic regions. However, the most common pediatric circuit consisted of a hard-shell (open) venous reservoir, an arterial roller pump, and a hollow-fiber membrane oxygenator with a separate or integrated arterial filter. Compared with our previous surveys, there was increased utilization of all types of safety devices. The use of an electronic perfusion record was reported by 50% of NA centers and 31% of NNA centers. There was wide regional variation in cardioplegia delivery systems and cardioplegia solutions. Seventy-nine percent of the centers reported the use of some form of modified ultrafiltration. The survey demonstrated that there remains variation in perfusion practice for pediatric patients. Future surveys will be useful to evaluate the adoption of emerging perfusion practice guidelines.

Imaging and monitoring in minimally invasive valve surgery using an intra-aortic occlusion device: a single center experience.

BackgroundMinimally invasive approach through a right mini-thoracotomy is a world-wide used procedure for mitral valve surgery. We performed a retrospective analysis based on our center experience in order to propose an effective, safe and reproducible method using an intra-aortic occlusion device.MethodsThis is a retrospective analysis on 48 consecutive patients undergoing mitral valve surgery through a right anterolateral mini-thoracotomy in our center. An intra-aortic occlusion device was used for aortic clamping and cardioplegia delivery. Simultaneous multi-plane three-dimensional echocardiography imaging was acquired to detect the venous cannulas position, the intra-aortic device location in the ascending aorta, the balloon inflation, the complete occlusion of the aorta, the cardioplegia delivery, the origin and the blood flow in the right coronary artery. Aortic root pressure was measured by the tip of the intra-aortic occlusion device. A bilateral upper extremity invasive arterial pressure monitoring was detected. Neuromonitoring was performed through bilateral cerebral oximetry.ResultsThe analysis has shown no aortic dissection, neurological damage type 1 and myocardial ischemia in the study population. In 3 cases a distal displacement of the intra-aortic occlusion device was promptly detected by the combined use of echocardiographic imaging and by a drop of the right cerebral oximetry saturation and of the right radial artery pressure.ConclusionsThe combined use of transesophageal simultaneous multi-plane three- dimensional echocardiography imaging, bilateral upper extremity invasive arterial pressure monitoring, aortic root pressure and cerebral oximetry is an effective, safe and reproducible method in patients undergoing minimally invasive valve surgery using an intra-aortic occlusion device.

COMPARISON OF THE EFFECT OF ANTEGRADE AND ANTEGRADE/RETROGRADE CARDIOPLEGIA ON THE OUTCOME OF CORONARY ARTERY BYPASS GRAFT SURGERY FOR SEVERE CORONARY ARTERY DISEASE

Objective: To compare the early outcome of Coronary Artery Bypass Graft surgery using a combination of antegrade and retrograde cardipoplegia with that utilizing antegrade cardioplegia alone in triple vessel coronary artery disease.&#x0D; Study Design: Comparative cross-sectional study.&#x0D; Place and Duration of Study: Department of Adult Cardiac Surgery of Armed Forces Institute of Cardiology and National Institute of Heart Diseases, Rawalpindi, from Sep 2013 to Apr 2019.&#x0D; Methodology: A total of 160 patients with triple vessel coronary artery disease who underwent CABG surgery for 90% or greater stenos is in at least one major vessel in each of the three territories, namely the left anterior descending, the circumflex and the right coronary artery were investigated retrospectively. These were divided into 2 equal groups on the basis of the technique of administration of cardioplegia: in group-1 only ante grade blood cardioplegia was administered for myocardial protection and group-2 was given ante grade and retrograde cardiolplegia. Clinical outcomes like peri-operative mortality and morbidity were recorded, and serum creatine kinase MB, lactate, and mixed venous oxygen saturation levels were monitored. Two dimensional echocardiogram was performed on the 6th post-operative day and follow-up visits were planned 1 week and 4 weeksafter discharge from hospital.&#x0D; Results: There were 2 (2.5%) early deaths in group-1 and no peri-operative mortality in group-2. Five patients in group-1 (6.25%) and 2 (2.5%) in group-2 had non-fatal peri-operative myocardial infarction. However, significant differences included increased incidence of intra-operative ventricular dysrythmias, higher CK-MB levels at 24 hours after surgery, and increased requirement of intra-aortic balloon pump and inotropic support in Group-1.&#x0D; Conclusion: We conclude from this study that the combined delivery of ante grade and retrograde cardioplegia during CABG surgery for triple vessel coronary artery disease provides better myocardial protection and hence better outcome than antegrade cardioplegia alone.Keywords: , , ,

Myocardial oxygen consumption during histidine-tryptophan-ketoglutarate cardioplegia in young human hearts.

Energy demand and supply need to be balanced to preserve myocardial function during paediatric cardiac surgery. After a latent aerobic period, cardiac cells try to maintain energy production by anaerobic metabolism and by extracting oxygen from the given cardioplegic solution. Myocardial oxygen consumption (MVO2) changes gradually during the administration of cardioplegia. MVO2 was measured during cardioplegic perfusion in patients younger than 6 months of age (group N: neonates; group I: infants), with a body weight less than 10 kg. Histidine-tryptophan-ketoglutarate crystalloid solution was used for myocardial protection and was administered during a 5-min interval. To measure pO2 values during cardioplegic arrest, a sample of the cardioplegic fluid was taken from the inflow line before infusion. Three fluid samples were taken from the coronary venous effluent 1, 3 and 5 min after the onset of cardioplegia administration. MVO2 was calculated using the Fick principle. The mean age of group N was 0.2 ± 0.09 versus 4.5 ± 1.1 months in group I. The mean weight was 3.1 ± 0.2 versus 5.7 ± 1.6 kg, respectively. MVO2 decreased similarly in both groups (min 1: 0.16 ± 0.07 vs 0.36 ± 0.1 ml/min; min 3: 0.08 ± 0.04 vs 0.17 ± 0.09 ml/min; min 5: 0.05 ± 0.04 vs 0.07 ± 0.05 ml/min). We studied MVO2 alterations after aortic cross-clamping and during delivery of cardioplegia in neonates and infants undergoing cardiac surgery. Extended cardioplegic perfusion significantly reduces energy turnover in hearts because the balance procedures are both volume- and above all time-dependent. A reduction in MVO2 indicates the necessity of a prolonged cardioplegic perfusion time to achieve optimized myocardial protection.

Cirugía de arco aórtico con circulación extracorpórea en período neonatal

IntroductionAortic arch repair has shifted from deep hypothermia plus circulatory arrest to cerebral perfusion at tepid temperatures. A step forward is simultaneous brain-coronary perfusion, allowing beating-heart arch surgery. MethodsA “Y” cannula from the arterial line delivers oxigenated blood to brain and heart. The arch is repaired on a beating heart at 25°C. Intracardiac repair is performed after running cardioplegia through the root line. 68 patients are classified into three groups. A: Norwood (9 neonates); B: aortic arch (20 children); C: aortic arch plus intracardiac repair (39 patients). Associated anomalies in group C: ventricular septal defect (15), arterial switch (9), atrial septal defect (6), cor triatriatum (3), aortic commissurotomy (2), comprehensive repair (2), ostium primum (1), Yasui (1). Fourteen lately patients had their descending aorta additionally cannulated to achieve a total body perfusion strategy. ResultsMean by-pass time was 155minutes (range 63-353). Mean brain-coronary perfusion was 36minutes (18-60). Mean coronary ischemia was 34minutes (0-160). The heart was not arrested in group B patients. Follow-up was complete for a mean of 52 months (2-78). Five patients died in the postop. Three requiered angioplasty for recoarctation. ConclusionsSelective brain-coronary perfusion is feasible and easy to switch to conventional cardioplegia delivery. Coronary ischemia can be notably reduced, being even zero minutes in isolated arch surgery. Total body perfusion may reduce morbidity in neonatal arch surgery.

Using near-infrared spectroscopy myocardial oximetry to monitor myocardial oxygen balance in a swine model of cardiac surgery: a descriptive study.

Monitoring of the adequacy of myocardial protection with cardioplegia is nearly non-existent in clinical cardiac surgical practice and instead relies on well-defined protocols for delivery of cardioplegia often resulting in inadequate protection. We hypothesized that Near Infrared Spectroscopy technology could be useful in the monitoring of the myocardial oxygen state by attaching the monitors to the epicardium in a porcine model of cardiac surgery. The experiments were conducted with 3 different protocols of 2 pigs each for a total of 6 pigs. The objective was to induce episodic, oxygen supply-demand mismatch. Methods for decreased supply included decreasing coronary blood flow, coronary blood hypoxemia, coronary occlusion, hypovolemia, and hypotension. Methods for increase demand included rapid ventricular pacing and the administration of isoproterenol. Changes in myocardial tissue oximetry were measured and this measurement was then correlated with blood hemoglobin saturations of oxygen from coronary sinus blood samples. We found that decreases in myocardial oxygen supply or increases in demand due to any of the various experimental conditions led to decreases in both myocardial tissue oximetry and hemoglobin oxygen saturation of coronary sinus blood with recovery when the conditions were returned to baseline. Correlation between myocardial tissue oximetry and hemoglobin oxygen saturation of coronary sinus blood was moderate to strong under all tested conditions. This may have translational applications as a monitor of adequacy of myocardial protection and the detection of coronary occlusion.

Mitigating cardiac dysfunction by TOE-guided cardioplegia and mitral valve repair.

Based on current guidelines, 15% to 20% of patients undergoing mitral valve repair for regurgitation develop left ventricular dysfunction (ejection fraction < 50%-55%) despite a normal baseline. Two schools of thought have been debated: preexisting myocardial disease or suboptimal intraoperative myocardial protection. In our view, they could be reconciled. It is well recognized that left ventricular ejection fraction with a standard cut off at 50%-55% has limited sensitivity in detecting early systolic impairment in mitral regurgitation patients. Mitral regurgitation also leads to mitochondrial oxidative stress, thus rendering the myocardium more susceptible to ischemia-reperfusion injury and precipitating postoperative cardiac dysfunction. The fall in left ventricular ejection fraction early after mitral valve repair was shown to be caused by the reduction in both myocardial contractility and left ventricular stroke volume. To mitigate the risk to myocardial reperfusion injury, appropriate cardioplegia volume and distribution and well-defined surgical repair processes are equally important. We use transesophageal echocardiography-guided cardioplegia delivery, imaging the intramyocardial flow and ensuring adequate protection of the subendocardium during mitral valve repair. Mild aortic regurgitation on a beating heart often leads to left ventricular dilatation with diminished cardioplegia flow in the myocardium, thus requiring direct ostia cardioplegia. Systematic transesophageal echocardiography assessment before surgery is essential for establishing the mitral regurgitation mechanisms and translating them into precise surgical repair strategies. The benefits of transesophageal echocardiography-guided cardioplegia delivery warrant further clinical trials in order to evolve into part of a high surgical standard.

A SINGLE-CENTRE, FIVE-YEAR EXPERIENCE WITH DCD HEART TRANSPLANTATION

Introduction: In 2014 the world first DCD heart transplant with distant procurement (DPP) was performed in Sydney, Australia. Programs are now established in the UK and Europe, as well as a recently commenced multi-centre trial in the USA, with >150 performed worldwide. In established centres, DCD donors account for >20% of heart transplants with excellent early- and mid-term outcomes. Despite these encouraging results, there is still much to be learnt about DCD heart transplantation, and with increasing numbers of hospitals wishing to start DCD heart programs this paper will describe the protocols, lessons learnt and current outcomes from our experience. Materials and Methods: Forty-one DCD heart transplants were performed at our institution between July 2014 and February 2020, utilising a DPP and ex-situ perfusion protocol. Male or female DCD donors under the age of 55 years with no known history of cardiac disease were accepted for retrieval. Recipient selection was based on blood group and cross-matching outcomes, heart mass, and clinical urgency. The donor hearts were perfused on the TransMedics OCS device as outlined in Table 1.For analysis, donor details were collected using electronic donor records (Donate Life, Australia) with recipient data collected from clinical notes and electronic databases at our institution. Results: Patients receiving DCD allografts had excellent outcomes with 97.6 and 95.1% 1- and 5-year survival, respectively.In spite of the similar donor and recipient profiles and a similar rate of utilization of allografts reperfused on the OCS device (74% and 72%, early and late cohort, respectively), the rate of delayed graft function requiring ECMO support has dropped dramatically, from 35% to 14%.Interestingly, prolongation of the functional warm ischemic time was not associated with an increased rate of ECMO, however prolongation of the asystolic warm ischemic time was. A longer agonal period from withdrawal to circulatory arrest was in fact associated with a lower rate of ECMO.Discussion: Over our DCD program experience we have made several changes likely to have contributed to the reduced perioperative ECMO requirement. Primarily, we have adopted a more ‘protective’ approach to the management of the heart on the OCS device, targeting in particular lower coronary flows, with a view to reducing endothelial dysfunction and myocardial oedema. In addition, a design change to the OCS module now allows for a controlled cooling of the heart to 16°C prior to delivery of cardioplegia, proving superior protection to the heart during implantation. Conclusion: DCD heart transplantation clearly provides an additional source of donor allografts with excellent recipient outcomes. Our experiences have reinforced the benefit of a ‘protective’ perfusion strategy on the OCS device, and also raise questions about the true tolerable warm ischemic time, which requires further investigation. Curran Foundation.

Alternative technique of long acting cardioplegia delivery results in less hemodilution.

Preparation of del-Nido cardioplegia and its delivery technique can cause significant hemodilution. The resultant effects from hemodilution are largely proportionate to the use of a dual circuit. We opted for a custom-disposable single cardioplegia circuit instead of a dual circuit. We describe an alternative technique of del-Nido cardioplegia delivery and initial clinical experience with it at National University Hospital, Singapore. This is a retrospective analysis of data from January 2017 to April 2019, comprising of 177 patients of heart surgery and reflecting a single center database survey under the National Health Care Group. Of the 177 patients who underwent surgery with del-Nido cardioplegia, 76 (42.9%) were valve-only procedures and 5 (2.8%) were coronary artery bypass graft-only procedures. Ultrafiltration was utilized in 132 (62.6%) patients, whereas filtrate volume was 2200 [150-9500] mL. The alternative technique of del-Nido cardioplegia delivery adopted by National University Hospital advocates for a single pump, single circuit system. The retrospective institutional data highlighted safe delivery of del-Nido cardioplegia using this technique in a range of procedures. Besides the safe delivery of del-Nido cardioplegia, the National University Hospital Technique reduces hemodilution and provides other technical benefits including a steeper temperature gradient, modification of circuit configuration to deliver another cardioplegia while on bypass, as well as re-configuration of clamps to spike the base solution.

Myocardial protection in cardiac surgery: how limited are the options? A comprehensive literature review.

For patients undergoing cardiopulmonary bypass, myocardial protection is a key for successful recovery and improved outcomes following cardiac surgery that requires cardiac arrest. Different solutions, components and modes of delivery have evolved over the last few decades to optimise myocardial protection. These include cold and warm and blood and crystalloid solution through antegrade, retrograde or combined cardioplegia delivery approach. However, each method has its own advantages and disadvantages, posing a challenge to establish a gold-standard cardioplegic solution with an optimised mode of delivery for enhanced myocardial protection during cardiac surgery. The aim of this review is to provide a brief history of the development of cardioplegia, explain the electrophysiological concepts behind myocardial protection in cardioplegia, analyse the current literature and summarise existing evidence that warrants the use of varying cardioplegic techniques. We provide a comprehensive and comparative overview of the effectiveness of each technique in achieving optimal cardioprotection and propose novel techniques for optimising myocardial protection in the future.

Novel Cardioplegia Delivery in Patients with Severe Aortic Regurgitation.

During aortic valve replacement (AVR) in patients with severe aortic regurgitation (AR), repeated delivery of cardioplegia into the coronary ostia using a routine infusion cannula may induce coronary ostial injury. This study aims to introduce a new no-touch delivery method with reduced time and similar or better outcomes. Preliminary results have shown that no-touch cardioplegia delivery method was a simple, safe, and effective approach for cardioplegia infusion during AVR in patients with severe AR.

Comparison of heat monitoring-based myocardial protection strategy with classic myocardial protection method in isolated coronary artery bypass surgery patients.

In this study, we aimed to compare patients who have a myocardial protection strategy based on myocardial temperature monitorization with those who had myocardial protection with conventional intermittent cardioplegia. Twenty-six patients undergoing coronary artery bypass graft surgery were included into the study. Patients were prospectively grouped into two; myocardial protection based on temperature monitoring (group 1, n=11) and those who had cardioplegia every 20min (group 2, n=15) during aortic cross-clamping. In all patients, cold blood cardioplegia was used. Coronary sinus blood sampling was performed immediately before aortic cross-clamping, after 2, 20, and 40min of aortic clamping and tumor necrosis factor-alpha, malondialdehyde, creatinine kinase-myocardial band isoenzyme (MB), troponin I, lactate, and pH were studied. In addition, myocardial biopsy was taken before and immediately after cross-clamping to evaluate cardiomyocyte apoptosis with caspase-3 tunnel immunostaining. There were no differences in clinical parameters like early mortality, extubation time, inotropic requirements, postoperative drainage, intensive care unit, and hospitalization time between two groups. In addition, blood and blood products were similar in two groups. In group 2, after cross-clamping, troponin I and creatinine kinase-MB values were significantly higher than the other group. In myocardial biopsies, the caspase immunostaining score, before removal of aortic cross-clamp was significantly higher in group 2 than the samples taken before aortic clamping. Our results show that there is no difference between temperature-based myocardial protection strategy with conventional intermittent cardioplegia delivery. We think that the number of patients in our study is less and that the patient population is not a homogeneous structure is the most important limiting factor of our study. Increasing the number of patients, with particularly those who have myocardial dysfunction would help augment the possible different effects of two cardioplegic techniques on myocardial protection.

Evaluation of attention, perception, and stress levels of clinical cardiovascular perfusionists during cardiac operations: a pilot study.

Performing cardiopulmonary bypass is a complex task which involves evaluating visual input from patient monitors and technical parameters displayed at the heart-lung machine console as well as reacting to other sensory input. Only few studies are available concerning the competency requirements for clinical cardiovascular perfusionists, including attention, perception, and coping with mental stress. This study aims at evaluating attention, perception, and stress levels of clinical cardiovascular perfusionists during cardiopulmonary bypass. Nine clinical cardiovascular perfusionists voluntarily offered to participate in the study. Participants were asked to wear Tobii 2 eye-tracking glasses throughout the procedures. Specific time points were analyzed (cardiopulmonary bypass on, initial cardioplegia delivery, steady state, cross-clamp off, and weaning from cardiopulmonary bypass). Data acquisition was supplemented by participants' self-evaluation regarding their stress levels and by National Aeronautics and Space Administration Task Load Index (NASA TLX) questionnaires. Seven datasets were sufficient to be evaluated. The clinical cardiovascular perfusionists' professional experience ranged from 0.5 to 24 years. Evaluation of eye-tracking data revealed large variations in areas of interest hits, fixation, and dwell times. Across all phases, the venous reservoir, mean arterial pressure, arterial pump display, cardioplegia control, and data management system received the highest levels of attention. Pupil diameter measurements increased at start of cardiopulmonary bypass, cardioplegia delivery, and weaning off, but returned to base level during steady state. Clinical cardiovascular perfusionists' self-evaluation showed that subjective stress level was highest at the start and the end of the procedure. NASA TLX questionnaires revealed medium-to-high mental and temporal workloads, but low physical workloads. Performance, effort, and frustration indices showed medium workloads. During cardiopulmonary bypass, perfusionists are subjected to stress. Peak stress levels were highest during start and end of cardiopulmonary bypass. Furthermore, visual attention and perception varied between the operative phases. Further studies are indicated to evaluate the design of heart-lung machines and stress-coping strategies during cardiopulmonary bypass.

Iatrogenic Injuries during Retrograde Delivery of Cardioplegia- Prevention, Diagnosis and Management: A Collective Review

Iatrogenic Injuries during Retrograde Delivery of Cardioplegia- Prevention, Diagnosis and Management: A Collective Review

Management of Patients With Coronary Artery Malperfusion Secondary to Type A Aortic Dissection

This study reviewed our experience with coronary artery (CA) malperfusion secondary to type A aortic dissection. Between 2002 and 2017, 76 patients presented with CA malperfusion, with a dissection flap limited to the aorta in the region of the coronary ostium (type A lesion) in 26 (34%), with a dissection flap involving the CA itself (type B lesion) in 32 (42%), or with complete avulsion of the CA (type C lesion) in 18 (24%). Ostial repair was successfully performed in 23 type A patients (88%), in 20 type B patients (63%), and in no type C patient (0%). CA bypass grafting was performed when antegrade cardioplegia could not be applied in all 18 type C patients (100%) and in 5 type B patients (16%) because of a primary entry at the coronary ostium and in 7 patients (type A: 3 patients [12%], type B: 4 patients [13%]) with evidence of CA disease (p < 0.001). Perioperative mortality in patients with CA malperfusion was high (18 patients [24%]), but there was no difference in short-term (p= 0.153) or long-term survival (log-rank p= 0.542). Also, a landmark analysis showed equal survival of discharged patients with and without CA malperfusion (log-rank p= 0.645). We recommend CA bypass grafting in patients with type C lesions or in patients with underlying CA disease for optimal delivery of cardioplegia and ostial pledgetted suture repair in patients with type A lesions or type B lesions when the administration of antegrade cardioplegia is successful.

RF30 INTEGRATED PERCUTANEOUS AND MINIMALLY INVASIVE APPROACH FOR HEART VALVE SURGERY: THE “HYBRID WAY” TECHNIQUE

Abstract Background and Aim: The aim of this study was to evaluate in-hospital and short-term results of our minimally invasive hybrid approach in a cohort of patients with isolated,double or triple heart valve disease. Methods: Between March 2014 and March 2018,we operated on 215 patients using a minimally invasive hybrid technique which includes limited skin incision,upper hemisternotomy,central arterial cannulation and peripheral percutaneous venous cannulation for the positioning of venous cannula,pulmonary artery vent and retrograde cardioplegia delivery line. Results: Of the total cohort,128 (59.5%) patients underwent aortic (AVS),77 (35.8%) mitral (MVS) and 10 (4.7%) combined aortic and mitral valve surgery (CVS).Median age was 72.5 (range:63.8–77),62 (54–71) and 66 (59.8–72) years for AVS,MVS and CVS,respectively.Endovent and Proplege (Edwards Lifesciences,Irvine,California,USA)were used in 63.3% and 32% patients of the AVS group,respectively.Mean (SD) cardiopulmonary bypass and aortic cross-clamp times were 115.2 (28.3),144.4 (42.6),182.0 (24.2) and 81.2 (21.8),97.8 (21.6) and 131.6 (15.9) minutes in the AVS,MVS and CVS group,respectively.Mean (SD) postoperative length of stay was 7.8 (5.9),7.3 (2.7) and 6.8 (1.1) days in the AVS,MVS and CVS group,respectively without any in-hospital deaths and low rate of complications.After a median follow-up of 16,13.5 and 14 months,survival was 99%,100% and 100% for the AVS,MVS and CVS group and echocardiography did not reveal any significant valvular dysfunction. Conclusions: Hybrid MIS appears to be feasible,safe and reliable with excellent in-hospital and short-term results.Key strength of this tecnique is the opportunity to perform all combinations of heart valves surgery with one single easy-learning surgical approach.

Incidence of Cerebral Microemboli in Single-Dose vs. Multidose Cardioplegia in Adult Cardiac Surgery

Cerebral microemboli have been associated with neurocognitive deficits after cardiac operations using cardiopulmonary bypass (CPB). Interventions by the perfusionist and alterations in blood flow account for a large proportion of previously unexplained microemboli. This study compared the incidence of microemboli during cardiac operations using conventional (multidose) and del Nido (single-dose) cardioplegia delivery. Transcranial Doppler ultrasonography was used to detect microemboli in bilateral middle cerebral arteries of 30 adult patients undergoing cardiac operations using CPB and aortic clamping. Multidose conventional blood cardioplegia (CBC) was used in 15 patients and single-dose del Nido cardioplegia (DNC) in 15. Manual count of microemboli during cross-clamp and during administration of cardioplegia was performed. Baseline preoperative characteristics were similar between groups. There were no differences in the ascending aortic atheroma grade (1.4 ± .4 CBC vs. 1.6 ± .7 DNC,p= .44), bypass times (141 ± 36 minutes CBC vs. 151 ± 33 minutes DNC,p= .64), and cross-clamp times (118 ± 32 minutes CBC vs. 119 ± 45 minutes DNC,p= .95). The use of multidose CBC was associated with a seven-fold increase in the number of microemboli per minute of bypass (1.65 ± 1 vs. .24 ± .18 emboli/min DNC,p= .0004). In this prospective pilot study, we found that the use of single-dose cardioplegia strategy led to fewer cerebral microemboli when compared with the traditional multidose approach. Our findings warrant further investigation of various cardioplegia strategies and neurologic outcomes in larger cohorts.

Albumin priming improves the efficiency of the Minntech HPH Jr. hemoconcentrator.

The desired use of the HPH Jr. is optimal due to the low priming volume; however, the lower rate of volume removal necessitates utilization of a larger hemofilter. Larger hemofilters carry a higher prime volume, which is impactful in the pediatric setting. Pediatric cardiac surgery patients under 18 kilograms requiring cardiopulmonary bypass were randomly assigned to one of two study groups. Group 1 (coated) contained an HPH Jr. hemofilter that was primed with the addition of 25% albumin and heparin. Group 2 (non-coated) contained an HPH Jr. hemofilter that was primed with only Normosol-R®. After cardioplegia delivery, zero balance ultrafiltration (ZBUF) was initiated and maintained for thirty consecutive minutes. The flow through the hemofilter was standardized at 70 ml/min and the vacuum applied to the effluent line was set at -150 mmHg. Effluent fluid removal was measured at the termination of thirty minutes and compared between the groups. Group comparisons between the coated vs non-coated hemofilter groups were assessed using two-sample t-tests or the Mann-Whitney U test, when appropriate. Forty-two patients were included in the analysis. There were 22 patients who had the non-coated hemofilter and 20 patients with a coated hemofilter. The differences between the two groups are illustrated in Table 1. There was a statistically significant higher ultrafiltration volume with the coated hemofilter group (p=0.008) (Figure 1). These results illustrate the improved efficiency of the HPH Jr. with the addition of 25% albumin and heparin during the priming process.

Beating-heart aortic arch surgery in neonates and infants.

Aortic arch repair has been shifted from deep hypothermia plus circulatory arrest to cerebral perfusion at tepid temperatures. A step forward is a simultaneous brain-coronary perfusion, allowing beating-heart arch surgery. A 'Y' cannula from the arterial line delivers oxygenated blood to brain and heart. The arch is repaired on a beating heart at 25°C. Intracardiac repair is performed after running cardioplegia through the root line. Fifty patients are classified into 3 groups: A, Norwood (8 neonates); B, aortic arch (14 children) and C, aortic arch plus intracardiac repair (28 patients). Associated anomalies in Group C are as follows: ventricular septal defect (10), arterial switch (5), atrial septal defect (4), cor triatriatum (3), aortic commissurotomy (2), comprehensive repair (2), ostium primum (1) and Yasui (1). The mean bypass time was 161 ± 54.44 (range 93-312) min. Mean brain-coronary perfusion was 37.26 ± 10.54 (18-60) min. Mean coronary ischaemia was 31 ± 32.40 (0-160) min. The heart was not arrested in Group B patients. Follow-up was complete for a mean of 30 (1-48) months. Four patients died in the postoperative period. Two required angioplasty for recoarctation. Selective brain-coronary perfusion is feasible and easy to switch to conventional cardioplegia delivery. Coronary ischaemia can be notably reduced and even 0 min in isolated arch surgery.

The practicalities of establishing a porcine isolated heart model.

The isolated heart apparatus is over 100 years old, but remains a useful research tool today. While designs of many large animal systems have been described in the literature, trouble-shooting and refining such a model to yield a stable, workable system has not been previously described. This paper outlines the issues, in tabular form, that our group encountered in developing our own porcine isolated heart rig with the aim of assisting other workers in the field planning similar work. The paper also highlights some of the modern applications of the isolated heart apparatus. Methods Landrace pigs (50-80 kg) were used in a pilot project to develop the model. The model was then used in a study examining the effects of various cardioplegic solutions on function after reanimation of porcine hearts. During the two projects, non-protocol issues were documented as well as their solutions. These were aggregated in this paper. Issues faced by the group without explicit literature solutions included pig size selection, animal acclimatisation, porcine transoesophageal echocardiography, cannulation and phlebotomy for cross-clamping, cardioplegia delivery, heart suspension and rig tuning. Prior recognition of issues and possible solutions faced by workers establishing a porcine isolated heart system will speed progress towards a useable system for research. The isolated heart apparatus remains applicable in transplant, ischaemia reperfusion, heart failure and organ preservation research.