Warm Blood Cardioplegia Group Research Articles

Effects of Del Nido and Terminal Warm Blood Cardioplegia on Myocardial Protection and Rhythm in Isolated CABG Patients.

To investigate the effect of using del Nido cardioplegia+terminal hot-shot blood cardioplegia on myocardial protection and rhythm in isolated coronary bypass patients. A total of 122 patients were given cold (+4-8C') del Nido cardioplegia antegrade and evaluated. Del Nido+terminal warm blood cardioplegia (TWBCP) was applied to 63 patients out of 122 patients, while del Nido cardioplegia alone was applied to the other 59 patients. The preoperative and postoperative data of the patients were recorded and compared. There was a significant statistical difference between the groups, in terms of volume with more cardioplegia in the del Nido+terminal warm blood cardioplegia group. Although there was no significant difference between cardiac arrest times in both groups, a statistically significant difference was found in the del Nido+terminal warm blood cardioplegia group in the starting to work time of the heart. No difference found between the groups regarding myocardial preservation. We can add a return to spontaneous sinus rhythm to the advantages of terminal warm blood cardioplegia and del Nido cardioplegia in literature. We think it would be a good strategy to extend the safe ischemic time limit of del Nido to 120 minutes with a terminal warm blood cardioplegia. It seems that cardioplegia techniques that will be developed by adding the successful and superior results of crystalloid cardioplegia applications, such as single dose del Nido in various open heart surgery operations and the superior myocardial return effects of terminal warm blood cardioplegia, will be used routinely in the future.

The effect of cold crystalloid versus warm blood cardioplegia on the myocardium during coronary artery bypass grafting

Background: The optimal cardioplegic solution is still debated. The objective of this study was to compare the effect of cold crystalloid versus warm blood cardioplegia on the myocardial injury during coronary artery bypass grafting.
 Methods: The study included 34 consecutive patients who underwent elective primary on-pump isolated coronary artery bypass grafting from 2016 to 2019. We randomly assigned the patients into two groups. Group (ICCC) (n= 17) received intermittent antegrade cold crystalloid cardioplegia and Group (IWBC) (n= 17) received intermittent antegrade warm blood cardioplegia.
 Results: There was no difference in the preoperative and operative variables between groups. The time taken by the heart to regain normal sinus rhythm was significantly longer in the cold crystalloid group (7.06 ± 1.8 vs. 2.17 ± 0.8 minutes, p<0.001) with a higher rate of reperfusion ventricular arrhythmia (35% versus 6%; p=0.03) compared to the warm blood cardioplegia group. Both coronary sinus acid production and lactate level were significantly higher in the warm blood group than in the cold crystalloid group (p< 0.001 and 0.043, respectively). The ischemic ECG changes and the severity of new segmental wall motion abnormalities were non-significantly different between both groups (p= 0.68 and 0.67, respectively). Postoperative CK-MB and cTnI levels in all-time points were not significantly different between groups (p= 0.46 and 0.37, respectively). ICU (2.29 ± 0.77 vs. 2.41 ± 0.87 days, p= 0.68) and hospital stay (9.28 ± 0.76 vs. 9.42 ± 0.88 days, p= 0.62) were non-significantly different between both groups.
 Conclusion: Intermittent antegrade cold crystalloid cardioplegia was associated with attenuated myocardial metabolism. However, it was associated with a longer time to regain normal sinus rhythm and more reperfusion ventricular arrhythmias. We did not find differences in the clinical and echocardiographic outcomes and cardiac enzymes between cold crystalloid and warm blood cardioplegia.

Superior restoration of left ventricular performance after prolonged single-dose del Nido cardioplegia in conjunction with terminal warm blood cardioplegic reperfusion

ObjectivesAn incomplete restoration of left ventricular contractility after del Nido cardioplegia was noted in our recent study. This study tested the hypothesis that terminal warm blood cardioplegia promotes a prompt restoration of left ventricular performance after a prolonged single-dose del Nido cardioplegia. MethodsFourteen piglets were subjected to 120 minutes of arrest by del Nido cardioplegia without terminal warm blood cardioplegia (del Nido cardioplegia group; n = 7) or with terminal warm blood cardioplegia before reperfusion (terminal warm blood cardioplegia group; n = 7). The other 7 piglets underwent total cardiopulmonary bypass without ischemia/reperfusion for 150 minutes (control group). Left ventricular function was assessed by percent recovery of end-systolic elastance as the contractility and percent end-diastolic pressure–volume relationship as the compliance using a conductance catheter. Troponin T and the mitochondrial score were also measured. ResultsDepressed percent recovery of end-systolic elastance was sustained in the del Nido cardioplegia group, and a prompt restoration of end-systolic elastance was achieved using terminal warm blood cardioplegia (57.9 ± 17.8 vs 94.7 ± 13.1, P < .028). Percent end-diastolic pressure–volume relationship at the early phase was better in the terminal warm blood cardioplegia compared with the del Nido group (88.5 ± 24.0 vs 101.4 ± 16.8, P = .050). Troponin T was higher in the terminal warm blood cardioplegia compared with the control group (0.80% ± 0.21% and 1.49% ± 0.31%, respectively, P = .002). The mitochondrial score was equivalent in all groups. Spontaneous restoration to sinus rhythm was more frequent in the terminal warm blood cardioplegia group than in the del Nido cardioplegia group (6/7 vs 1/7, P < .028). ConclusionsThe supplementary use of terminal warm blood cardioplegia achieved prolongation of the safe ischemic time up to 120 minutes for a single-dose application.

Cold crystalloid versus warm blood cardioplegia in patients undergoing aortic valve replacement.

Myocardial protection techniques during cardiac arrest have been extensively investigated in the clinical setting of coronary revascularization. Fewer studies have been carried out of patients affected by left ventricular hypertrophy, where the choice of type and temperature of cardioplegia remain controversial. We have retrospectively investigated myocardial injury and short-term outcome in patients undergoing aortic valve replacement plus or minus coronary artery bypass grafting with using cold crystalloid cardioplegia (CCC) or warm blood cardioplegia (WBC). From January 2015 to October 2016, 191 consecutive patients underwent aortic valve replacement plus or minus coronary artery bypass grafting in normothermic cardiopulmonary bypass. Cardiac arrest was obtained with use of intermittent antegrade CCC group (n=32) or WBC group (n=159), according with the choice of the surgeon. As compared with WBC group, in CCC group creatine-kinase-MB (CK-MB), cardiac troponin I (cTnI), aspartate aminotransferase (AST) release, and their peak levels, were lower during each time points of evaluation, with the greater statistically significant difference at time 0 (P<0.05, for all comparisons). A time 0, CK-MB/CK ratio >10% was 5.9% in CCC group versus 7.8% in WBC group (P<0.0001). At time 0 CK-MB/CK ratio >10% in patients undergoing isolated aortic valve replacement was 6.0% in CCC group versus 8.0% in WBC group (P<0.01). No any difference was found in perioperative myocardial infarction (0% versus 3.8%), postoperative (PO) major complications (15.6% versus 16.4%), in-hospital mortality (3.1% versus 1.3%). In aortic valve surgery a significant decrease of myocardial enzymes release is observed in favor of CCC, but this difference does not translate into different clinical outcome. However, this study suggests that in presence of cardiac surgical conditions associated with significant left ventricular hypertrophy, i.e., the aortic valve disease, a better myocardial protection can be achieved with the use of a cold rather than a warm cardioplegia. Therefore, CCC can be still safely used.

Single Dose Inamrinone in Terminal Warm Cardioplegia in On-Pump Coronary Artery Bypass Patients

Background: Phosphodiesterase inhibitors (PDI) are used in cardiac surgery to improve and stabilize cardiac function after surgery. The aim of this study is to evaluate changes in hemodynamics and early outcomes when PDI (Inocor/inamrinone) is given in terminal warm blood cardioplegia to on-pump CABG only patients and compare results with patients who did not receive the drug. Material and methods: From April 2003 through September 2004 241 pts underwent elective on-pump CABG only surgery. 141 pts received Inocor in the terminal warm blood cardioplegia (Group 1) and 100 pts did not (Group 2). Results: Demographic data, preoperative EuroSCORE risk scores and operative details were similar. Of pts preoperatively in sinus rhythm (SR) 80.15% in Group 1 and 69.79% in Group 2 regained spontaneous SR (p = 0.07) after release of crossclamp. Inotropic support was needed in 5 pts in Group 1 and in 12 pts in Group 2, p = 0.02. Post cardiopulmonary by-pass (CPB) IABP support was needed for 4 pts in Group 2 and none for Group 1 pts, p = 0.01. There was no operative mortality in either Group and hospital/30 day mortality was similar (3/2.13% vs 3/3.00%, p = 0.69). There were no statistical difference in stay in postoperative intensive care unit (p = 0.15), total hospital stay (p = 0.07), appearance of postoperative atrial fibrillation (p = 0.23) or appearance of postoperative kidney injury (p = 0.27). Post CPB cardiac index improved 16.90% in Group1but decreased 1.49% in Group 2, p < 0.0001. Mean arterial pressure decreased 7.46%in Group 1 pts and 5.08% in Group 2 pts, p = 0.002, but no pts in either Group needed medication for too low blood pressure. Systemic vascular resistance decreased 28.40% in Group 1 and 9.02% in Group 2, p < 0.0001. Conclusions: Inamrinone in terminal warm blood cardioplegia (hot shot) is safe and effective way to improve and stabilize cardiac function after on-pump CABG surgery but does not affect short-term outcomes.

The Efficacy and Safety of Extending the Ischemic Time with a Modified Cardioplegic Technique for Coronary Artery Surgery

The need to intermittently discontinue the administration of cardioplegia in order to complete the surgical procedure is a major drawback of antegrade warm blood cardioplegia. An ischemic time of 15 minutes is generally considered safe based on empirical observation. The aim of this study was the evaluation of the efficacy and safety of an intermittent warm blood cardioplegia with intervals between administrations prolonged to 25 minutes. Ninety-seven patients undergoing primary elective coronary artery revascularization were prospectively randomized into two groups. The first, Intermittent Antegrade Warm Blood Cardioplegia (IAWBC) group, comprising 49 patients, received standard intermittent antegrade warm blood cardioplegia repeated every 15 minutes. The second, Modified Intermittent Antegrade Warm Blood Cardioplegia (M-IAWBC) group, comprising 48 patients, received intermittent antegrade warm blood cardioplegia supplemented with magnesium sulfate (MgSO(4)), delivered in volumes proportional to the ventricular mass and repeated every 25 minutes. The clinical outcomes were evaluated. The levels of creatine kinase-MB (CK-MB) isoenzyme, in addition to the echocardiographic assessment of septal dyskinesia and tricuspid annulus plane systolic excursion (TAPSE), have been used as markers of myocardial damage. There were no statistically significant differences in clinical outcomes, need for inotropes and vasodilators, length of stay in the intensive care unit, and postoperative levels of CK-MB between the two groups. Likewise, postoperative echocardiographic assessment showed no relevant differences. Administration of warm antegrade cardioplegic solution supplemented with MgSO(4), delivered in volumes proportional to ventricular mass every 25 minutes, provides adequate myocardial protection for coronary artery surgery.

Warm induction cardioplegia and reperfusion dose influence the occurrence of the post CABG TnI level

As a new biochemical marker cardiac troponin-I (CTnI) is a more sensitive and specific marker for detection of differences in myocardium injuries than other chemical enzymes. This study investigates the effect of warm induced and reperfusion blood cardioplegia on the release of troponin-I during the CABG. In our research, 24 three-vessel coronary artery disease (CAD) patients underwent CABG and were divided into two groups randomly: Group of warm induction and reperfusion blood cardioplegia (Group W N=12); Group of simple warm induction and no reperfusion (Group C N=12). The effect of myocardium protection of the two methods of myocardium protection were evaluated by clinical outcome, CTnI. Serial venous blood samples were obtained before and after surgery. In both groups, there were no differences in operative parameters. The level of CTnI increased from postoperative 6 h (P<0.05), reached peak in 24 approximately 72 h and recovered postoperatively on 6th day in both groups. Compared with group C, the plasma concentrations of CTnI in group W were significantly lower at 6 h, 24 h and 72 h (P<0.01). The results suggest that the method of warm induction and reperfusion blood cardioplegia reduces the leakage of CTnI than group of simple warm blood cardioplegia in CABG patients.

Cardioprotective effects and the mechanisms of terminal warm blood cardioplegia in pediatric cardiac surgery

Objectives Terminal warm blood cardioplegia has been shown to enhance myocardial protection in adult patients. However, the cardioprotective effects and the mechanisms of terminal warm blood cardioplegia in pediatric heart surgery were still unknown. Methods One hundred three consecutive patients were prospectively randomized to one of two groups. In the control group (n = 52), myocardial protection was achieved with intermittent hyperkalemic cold blood cardioplegia and topical cardiac cooling. In the terminal warm blood cardioplegia group (n = 51), this was supplemented with terminal warm blood cardioplegia before the aorta was declamped. Arterial and coronary sinus blood samples were analyzed to determine myocardial energy metabolism and tissue injury. Results There were no significant differences between the two groups in age (5.5 ± 0.6 years in the control group vs 5.6 ± 0.5 years in the terminal warm blood cardioplegia group), body weight (17.2 ± 1.4 kg in the control group vs 19.8 ± 1.7 kg in the terminal warm blood cardioplegia group), percentage of cyanotic heart diseases (50% in the control group vs 51% in the terminal warm blood cardioplegia group), number of patients who required right ventriculotomy (33% in the control group vs 39% in the terminal warm blood cardioplegia group), cardiopulmonary bypass time (194 ± 12.1 minutes in the control group vs 177 ± 8.6 minutes in the terminal warm blood cardioplegia group), aortic crossclamp time (83.3 ± 5.9 minutes in the control group vs 82.3 ± 5 minutes in the terminal warm blood cardioplegia group), lowest rectal temperature (27.4 ± 0.3°C in the control group vs 28.1 ± 0.3°C in the terminal warm blood cardioplegia group), and myocardial temperature (9.6 ± 0.6°C in the control group vs 9.6 ± 0.7°C in the terminal warm blood cardioplegia group). Spontaneous defibrillation occurred after reperfusion in 80% in the terminal warm blood cardioplegia group, which was significantly ( P < .05) higher than the control group (62%). The lactate extraction rate at 60 minutes of reperfusion was significantly ( P < .05) higher in the terminal warm blood cardioplegia group (9.0 ± 2.8%) than the control group (−3.3 ± 2.4%). The postreperfusion values of cardiac troponin T (7.4 ± 0.6 ng/mL vs 11.2 ± 1.0 ng/mL at 6 hours; 4.6 ± 0.6 ng/mL vs 9.3 ± 1.6 ng/mL at 18 hours) and heart-type fatty acid binding protein (137 ± 28 ng/mL vs 240 ± 30 ng/mL at 2 hours; 88 ± 19 ng/mL vs 162 ± 26 ng/mL at 3 hours) were significantly ( P < .05 vs the control group) lower in the terminal warm blood cardioplegia group. Conclusion Terminal warm blood cardioplegia enhances myocardial protection in pediatric cardiac surgery by an improvement in aerobic energy metabolism and a reduction of myocardial injury or necrosis.

The short-term and long-term effects of warm or tepid cardioplegia

Background: Clinical studies of myocardial protection rarely identify differences in hard clinical outcomes after surgery, either early or late, because most trials lack sufficient statistical power to deal with low-frequency events. Methods: Prospectively collected data concerning all isolated coronary bypass operations from November 1989 to February 2000 were analyzed to determine the effects of cold blood cardioplegia and warm or tepid blood cardioplegia on early and late outcomes after surgery. Warm blood cardioplegia was used in 4532 patients, whereas cold blood cardioplegia was used in 1532. The allocation of patients to receive warm blood cardioplegia and cold blood cardioplegia was random in 749 cases and according to surgeon preference in the remainder. Most patients in the cold blood cardioplegia group had surgery earlier in the time course of the study, and most in the warm blood cardioplegia group underwent surgery later. Results: Perioperative death, myocardial infarction, and death or myocardial infarction were all more common in the cold blood cardioplegia group than in the warm blood cardioplegia group (death 2.5% vs 1.6%, P =.027, adjusted odds ratio 1.45, 95% confidence interval 0.95-2.22, P =.09; myocardial infarction 5.4% vs 2.4%, P <.0001, adjusted odds ratio 1.86, 95% confidence interval 1.36-2.53, P <.0001; death or myocardial infarction 7.3% vs. 3.8%, P <.0001, adjusted odds ratio 1.70, 95% confidence interval 1.30-2.21, P <.0001). Actuarial survival at 60 months was 91.1% ± 1.4% in the warm blood cardioplegia group and 89.9% ± 1.3% in the cold blood cardioplegia group (P =.09), whereas freedom from death or myocardial infarction was 84.7% ± 1.8% and 83.2% ± 1.6%, respectively (P =.16). In multivariate models, cold blood cardioplegia was associated with poorer survival (risk ratio 1.30, 95% confidence interval 0.96-1.75, P =.09) and freedom from any death or late myocardial infarction (risk ratio 1.93, 95% confidence interval 1.56-2.39, P =.0001). Conclusions: In 6064 patients undergoing isolated coronary artery bypass grafting, warm or tepid blood cardioplegia may be associated with better early and late event-free survivals than is cold cardioplegia.J Thorac Cardiovasc Surg 2003;125:711-20

Intermittent Warm Blood Cardioplegia Preserves Myocardial β-Adrenergic Receptor Function

Background. Left ventricular dysfunction is frequently observed in patients after hypothermic cardioplegic arrest, and often inotropic intervention is necessary for patients to be successfully weaned from cardiopulmonary bypass (CPB). A myocardial β-adrenergic receptor (βAR) desensitization has been noted to occur after hypothermic CPB in patients undergoing coronary artery bypass grafting. This randomized study was undertaken to determine the effect of cardioplegic solution temperature on cardiac βARs. Methods. Two groups of patients (20 patients in each) scheduled for elective coronary artery bypass grafting underwent CPB with either intermittent warm or cold blood cardioplegia. The density of the βARs, the proportion of β 1- to β 2-adrenergic receptors, and the βAR coupling capacity to adenylate cyclase were determined in specimens of the right atrial tissue at baseline, during CPB, and after discontinuation of CPB. Plasma concentrations of catecholamines were also measured in both arterial and coronary sinus samples. Results. In both cardioplegia groups, no significant modification in either the βAR density or the proportion of β 1- to β 2-adrenergic receptors was detected. However, a significant decrease in adenylate cyclase activity after stimulation with isoproterenol was observed in the cold blood cardioplegia group during CPB ( p < 0.01) and 30 minutes after its discontinuation ( p < 0.05). Moreover, a significant decrease in adenylate cyclase activity during CPB was detected in this group after stimulation with sodium fluoride ( p < 0.05), but this pattern was found to be completely reversed by 30 minutes after discontinuation of CPB. No modification in the basal or stimulated adenylate cyclase activity was observed in the warm blood cardioplegia group during or after CPB. Conclusions. Our results confirm the finding from previous studies of a cardiac βAR desensitization after hypothermic cardioplegic arrest, and provide evidence of the advantages of intermittent warm blood cardioplegia in preserving the autonomic sympathetic function of the heart.

Hemodynamics and oxygen consumption during warm heart surgery

We compared the effects of normothermic cardiopulmonary bypass (CPB) with those of hypothermic CPB in patients who underwent coronary artery bypass grafting (CABG) with respect to hemodynamics and oxygen balance. The patients in our study were divided into two groups according to temperature during CPB: systemic normothermia combined with warm blood cardioplegia (group W,n=36) and systemic hypothermia combined with cold crystalloid cardioplegia (group C,n=26). In group W, the use of directcurrent (DC) defibrillators was less frequent after release of the cross clamp, and the duration of CPB and of reperfusion was shorter. After CPB, the cardiac index and arterial pressure were higher and the dosages of dopamine were lower in group W than in group C. The serum glucose level during and after CPB was lower and the base excess during CPB was higher in group W than in group C. Oxygen consumption ([Formula: see text]) was unchanged throughout the operation in group W, while it decreased during CPB and increased at the end of surgery in group C. The oxygen extraction ratio (ERo2) increased during CPB in group W, while it was unchanged throughout the operation in group C. Mixed venous oxygen saturation ([Formula: see text]) was maintained above 65% during and after CPB in group W and group C. Our results showed that normothermia may be superior to hypothermia during CPB with respect to recovery of cardiac function and avoidance of hyperglycemia. The whole-body oxygen demand-supply balance may be preserved during normothermic as well as hypothermic CPB.

Microvascular reactivity after crystalloid, cold blood, and warm blood cardioplegic arrest

The effects of three techniques of cardioplegic arrest on endothelium-dependent microvascular function of the right and left ventricles were examined in a canine model of cardiopulmonary bypass. Oxygenated cold crystalloid cardioplegia and cold blood cardioplegia groups, (n = 11 each) had hypothermic cardiopulmonary bypass (28 degrees C), topical cooling, antegrade arrest, and intermittent antegrade delivery. A warm blood cardioplegia group (n = 11) had normothermic cardiopulmonary bypass (37 degrees C), antegrade arrest, and continuous antegrade delivery. All groups underwent cardioplegic arrest for 1 hour followed by 1 hour of reperfusion. Dogs that did not have instrumentation were used as controls (n = 10). Coronary microvessels (100 to 200 microns in internal diameter) were examined in a pressurized, no-flow state with video microscopic imaging and electronic dimension analysis. Ischemic arrest with cold crystalloid cardioplegia significantly (p < 0.05) impaired endothelium-dependent relaxations in both ventricles to acetylcholine (left ventricle, 69% +/- 4%, and right ventricle, 73% +/- 5%, versus control left ventricle, 100% +/- 0.3%, and control right ventricle, 100% +/- 0.3%) and the calcium ionophore (left ventricle, 70% +/- 6%, and right ventricle, 68% +/- 3%, versus control left ventricle, 98% +/- 1%, and control right ventricle, 98% +/- 1%). In the cold blood cardioplegia group, endothelium-dependent relaxations to acetylcholine (left ventricle, 96% +/- 1%, and right ventricle, 87% +/- 4%) and the calcium ionophore (left ventricle, 88% +/- 3%, and right ventricle, 78% +/- 7%) were preserved. In the warm blood cardioplegia group, endothelium-dependent responses to acetylcholine (92% +/- 3%) and the calcium ionophore (96% +/- 1%) were preserved in the left ventricle, but the right ventricle showed reduced (p < 0.05) reactivity to the endothelium-dependent acetylcholine (77% +/- 8%) and the calcium ionophore (69% +/- 8%). Endothelium-independent relaxation to sodium nitroprusside was similar to controls in all groups for both ventricles, thus indicating normal smooth muscle responsiveness. Cardioplegic arrest with cold blood cardioplegia preserved the endothelium-dependent response in the right and left ventricles, whereas cold crystalloid cardioplegia impairs this response. Warm blood cardioplegia preserved the endothelium-dependent response in the left ventricle, but this response was reduced in the right ventricle. This suggests that blood cardioplegia and hypothermia may be important in protection of microvascular endothelium and that the right ventricle may be more vulnerable to damage than the left ventricle.

Revascularization for acute regional infarct: Superior protection with warm blood cardioplegia

Continuous retrograde warm blood cardioplegia was compared with two widely used hypothermic myocardial protection techniques in a canine model of acute regional myocardial ischemia with subsequent revascularization. Animals (n = 30) underwent 45 minutes of left anterior descending coronary artery occlusion then cardioplegic arrest (60 minutes), followed by separation from caidiopulmonary bypass and data collection. The cold oxygenated crystalloid cardioplegia group (CC; n = 8) and the cold blood cardioplegia group (CB; n = 10) had cardiopulmonary bypass at 28 °C, antegrade arrest, and intermittent retrograde delivery. The warm blood cardioplegia group (WB; n = 12) had normothermic cardiopulmonary bypass, antegrade arrest, and continuous retrograde delivery. Overall ventricular function (preload recruitable stroke work relationship; ergs × 10 3/mL) was significantly ( p < 0.001) better for WB (WB, 80 ± 11; CB, 67 ± 13; CC, 57 ± 12). Systolic function (maximum elastance relationship; mm Hg/mL) was also significantly ( p < 0. 001) better for WB (WB, 11.6 ± 3.6; CB, 8.6 ± 2.7; CC, 6.2 ± 1.3). Diastolic function (stress-strain relationship; dynes × 10 3/cm 2) revealed significantly ( p < 0.001) decreased compliance for CC (WB, 20 ± 6; CB, 19 ± 7; CC, 27 ± 11). Left anterior descending coronary artery regional adenosine triphosphate/adenosine diphosphate ratios were significantly ( p = 0.02) worse for CC (WB, 10.2 ± 2.3; CB, 9.4 ± 2.6; CC, 5.6 ± 1.5). Myocardial edema significantly ( p =0.03) increased over time only in the CC animals (WB, 0.4% ± 2.3%; CB, −0. 3% ± 3.6%; CC, 5.5% ± 2.3%). In this model of acute regional myocardial ischemia and revascularization, continuous retrograde warm aerobic blood cardioplegia provided superior myocardial protection compared with cold oxygenated crystalloid cardioplegia with intermediate results for cold blood cardioplegia.

Postischemic deterioration of sarcoplasmic reticulum: Warm versus cold blood cardioplegia

Impaired cardiac sarcoplasmic reticulum (SR) function, as evidenced by reduced SR Ca 2+ uptake rate and decreased SR Ca 2+-adenosine triphosphatase activity, has been found in postischemic “stunned” myocardium and in hearts subjected to hypothermic arrest. In this study, we compared the effects of retrograde continuous coronary sinus warm blood cardioplegia (WBC) and retrograde intermittent cold blood cardioplegia (CBC) on cardiac SR function and postischemic ventricular functional recovery in pig hearts. Twelve in situ isolated pig hearts supported by cardiopulmonary bypass were subjected to 120 minutes of cardioplegic arrest with either WBC (37 °C or CBC (6 ° to 10 °C), followed by 60 minutes of 37 °C reperfusion. Left ventricular global contractile function and coronary blood flow were measured before arrest and during reperfusion. Cardiac SR was isolated from left ventricular biopsy specimens, and 45Ca 2+ uptake by SR and SR Ca 2+-adenosine triphosphatase activity were determined. The recovery of left ventricular global contractile function as indicated by the maximum of the first derivative of left ventricular pressure was significantly improved in the WBC group compared with that of the CBC group (70% versus 46%; P < 0.05). The SR Ca 2+-adenosine triphosphatase activity was better preserved after 60 minutes reperfusion in WBC compared with CBC (0.31 ± 0.02 versus 0.20 ± 0.03 μM Pi/min/mg protein, p < 0.05), and the recovery of SR Ca 2+ uptake was significantly improved by WBC compared with CBC (1.15 ± 0.12 versus 0.83 ± 0.04 μM Ca 2+/min/mg protein; p < 0.05). These results indicate that the superiority of continuous WBC over intermittent CBC in promoting functional recovery may be related to its ability to improve postischemic SR function, which presumably plays a crucial role in regulating cellular Ca 2+ homeostasis.