Terminal warm blood cardioplegia improves the recovery of myocardial electrical activity. A retrospective and comparative study.

OBJECTIVE: The effect of terminal warm blood cardioplegia was analyzed in 191 patients undergoing either coronary artery bypass grafting (CABG) or prosthetic heart valve replacement between Jan. 1990 and Dec. 1995. METHODS: Patients were subdivided into 3 historical cohorts based on the method of myocardial protection: Group A (n = 106), multidose cold crystalloid glucose-potassium cardioplegia, alone; Group B (n = 37), cold crystalloid glucose-potassium cardioplegia plus terminal warm blood cardioplegia, Group C (n = 48), cardioplegia induction with cold crystalloid glucose-potassium cardioplegia, maintenance with multidose cold blood cardioplegia, and terminal warm blood cardioplegia. RESULTS: Of patients undergoing CABG, 5.6% of group A, 70.4% of group B, and 86.7% of group C spontaneously resumed sinus rhythm after aortic declamping, as did 9.1% of group A, 60.0% of group B, and 55.6% of group C of patients undergoing prosthetic heart valve replacement. The incidence of spontaneous recovery was significantly better in groups B and C than in group A (p < 0.05). Over 90% of patients without terminal warm blood cardioplegia developed ventricular fibrillation or tachycardia requiring electrical cardioversion (p < 0.05). Postoperatively, patients without terminal warm blood cardioplegia required temporary epicardial pacing more frequently than those with terminal warm blood cardioplegia (p < 0.05). In patients undergoing prosthetic heart valve replacement, groups B and C, the incidence of postoperative atrial fibrillation was significantly lower than in group A. CONCLUSION: Terminal warm blood cardioplegia thus promoted better postoperative electrophysiological cardiac recovery.     

Myocardial injury in hypertrophic hearts of patients undergoing aortic valve surgery using cold or warm blood cardioplegia.

OBJECTIVES: Myocardial protection techniques during cardiac surgery have been largely investigated in the clinical setting of coronary revascularisation. Few studies have been carried out on patients with left ventricular hypertrophy where the choice of delivery, and temperature of cardioplegia remain controversial. This study investigates metabolic changes and myocardial injury in hypertrophic hearts of patients undergoing aortic valve surgery using antegrade cold or warm blood cardioplegia. METHODS: Thirty-five patients were prospectively randomised to intermittent antegrade cold or warm blood cardioplegia. Left ventricular biopsies were collected at 5min following institution of cardiopulmonary bypass, 30min after cross-clamping the aorta and 20min after cross-clamp removal, and used to determine metabolic changes during surgery. Metabolites (adenine nucleotides, amino acids and lactate) were measured using high pressure liquid chromatography and enzymatic techniques. Postoperative myocardial troponin I release was used as a marker of myocardial injury. RESULTS: Ischaemic arrest was associated with significant increase in lactate and alanine/glutamate ratio only in the warm blood group. During reperfusion, alanine/glutamate ratio was higher than preischaemic levels in both groups, but the extent of the increase was considerably greater in the warm blood group. Troponin I release was markedly (P<0.05, Mean+/-SD) lower at 1, 24 and 48h postoperatively in the cold compared to the warm blood group (0.51+/-0.37, 0.37+/-0.22 and 0.27+/-0.19 vs. 0.75+/-0.42, 0.73+/-0.51 and 0.54+/-0.38ng/ml for cold vs. warm group, respectively). CONCLUSIONS: Cold blood cardioplegia is associated with less ischaemic stress and myocardial injury compared to warm blood cardioplegia in patients with aortic stenosis undergoing valve replacement surgery. Both cardioplegic techniques, however, confer sub-optimal myocardial protection.     

Blood warm reperfusion: a necessary adjunct to heart-valve surgery in low-risk patients?

AIM: The aim of this prospective, randomized study was to determine whether blood warm reperfusion improves myocardial protection provided by cold crystalloid cardioplegia in patients undergoing first-time elective heart-valve surgery, using cardiac troponin I release as the criterion for evaluating the adequacy of myocardial protection. METHODS: Seventy patients with a left ventricular ejection fraction greater than 40% were randomly assigned to 1 of 2 myocardial protection strategies: 1) cold crystalloid cardioplegia with no reperfusion or 2) cold crystalloid cardioplegia followed by 2-minute blood warm reperfusion before aortic unclamping. Cardiac troponin I concentrations were measured in serial venous blood samples drawn immediately prior to cardiopulmonary bypass and after aortic unclamping at 6, 9, 12, and 24 h. RESULTS: Randomization produced 2 equivalent groups. The total amount of cardiac troponin I released (7.17+/- 14.8 mg in the crystalloid cardioplegia with no reperfusion group and 5.82+/-4.66 mg in the crystalloid cardioplegia followed by blood warm reperfusion group) was not different (P > 0.2). Cardiac troponin I concentration did not differ for any sample in either of the 2 groups. The total amount of cardiac troponin I released was higher in patients who required inotropic support (9.14 +/-16.2 mg) than those who did not (4.73+/-4.52 mg; P = 0.009). CONCLUSIONS: Our study shows that adding blood warm reperfusion to cold crystalloid cardioplegia provides no additional myocardial protection in low-risk patients undergoing heart-valve surgery.     

Cardiac interleukin-6 release and myocardial recovery after aortic crossclamping. Crystalloid versus blood cardioplegia

BACKGROUND: Pro-inflammatory cytokines may play an important role in patient response to cardiopulmonary bypass (CPB). Since the myocardium is proposed to be a major source of cytokines, we studied the influence of the cardiolpegia type on interleukin-6 release and early myocardial recovery. METHODS: Experimental design: prospective, randomized study. Setting: university hospital, operative and intensive care. Patients: 20 consecutive patients (3 females) scheduled for elective coronary artery bypass grafting (CABG), mean age 62.8+/-5 years, history of myocardial infarction 11/20, left ventricular ejection fraction 62.9+/-15%. Interventions: patients were operated on using randomly either cold blood cardioplegia (B, n = 10) or cold crystalloid cardioplegia (C, n = 10). Measures: plasma levels of interleukin-6 (IL-6) were measured prior to CPB, after aortic declamping, after CPB, 1 hour, 6 hours and 12 hours postoperatively. RESULTS: Groups were comparable with respect to demographic data, left ventricular function, number of grafts, CPB and aortic crossclamp time. Group B patients demonstrated significant lower IL-6 levels after 1 hour (210+/-108 vs. 578+/-443 pg/ml), 6 hours (204+/-91 vs. 1210+/-671 pg/ml) and 12 hours (174+/-97 vs. 971+/-623 pg/ml). Post-CPB cardiac index was superior in group B (3.9+/-0.3 vs. 3.2+/-0.3 l/min/m2, p<0.05) with similar doses of inotropes. Group B patients could earlier be weaned off respirator (10+/-4 vs. 13+/-4 hours, p<0.05) and showed minor blood loss (635+/-211 vs. 918+/-347 ml, p<0.05). CONCLUSIONS: Inflammatory response to CPB is associated with delayed myocardial recovery. The use of blood cardioplegia may attenuate inflammatory reactions.     

Can cardioplegia management influence cytokine responses during clinical cardiopulmonary bypass?

BACKGROUND: Cytokines play an important role in the inflammatory response associated with cardiopulmonary bypass (CPB) and may contribute to postoperative complications. Although it has been shown that the production of tumor necrosis factor a (TNF-a) and interleukin (IL)-6 were higher following normothermic CPB than hypothermic CPB, whether different cardioplegic management could influence the release of cytokines remains unknown. METHODS: We compared the blood concentrations of four cytokines (TNF-a, IL-6, IL-8, and IL-10) in two groups of patients undergoing complete revascularization with CPB in the same study period. Seventeen patients received cold crystalloid cardioplegia at a Belgian center (group-CC), while 21 patients received warm blood cardioplegia at a center in Hong Kong (group-WB). Blood samples were collected before and after surgery in each patient. RESULTS: There were no differences between the 2 groups in terms of age, sex ratio, number of grafts, duration of CPB and aortic crossclamping. All patients survived their hospital stay. The levels of TNF-a, IL-6 and IL-8 after surgery were higher in group-CC than in group-WB. However, IL-10 levels were significantly lower at the end of surgery in group-CC than in group-WB. CONCLUSIONS: Our data suggest that the use of warm blood cardioplegia, rather than cold crystalloid cardioplegia, may reduce the inflammatory response to CPB. This observation warrants future randomized investigation to determine its clinical relevance.     

Randomized trial of intermittent antegrade warm blood versus cold crystalloid cardioplegia

BACKGROUND: We performed a prospective randomized trial to compare intermittent antegrade warm blood cardioplegia with intermittent antegrade and retrograde cold crystalloid cardioplegia. METHODS: Two hundred consecutive patients scheduled for isolated coronary bypass surgical procedures were randomized into two groups: Group 1 (n = 92) received cold crystalloid cardioplegia with moderate systemic hypothermia, group 2 (n = 108) received intermittent antegrade warm blood cardioplegia with systemic normothermia. Preoperative, intraoperative, and postoperative data were prospectively collected. RESULTS: For the same median number of distal anastomoses, cardiopulmonary bypass duration and total ischemic arrest duration (57.3 +/- 20.5 versus 75 +/- 22.1 minutes, p < 0.001) were shorter in group 2 than in group 1. Apart from a higher right atrial pressure in the cold cardioplegia group, no hemodynamic difference was observed. Aspartate aminotransferase, creatine kinase-MB fraction, and cardiac troponin I levels were significantly lower in group 2 than in group 1. Outcome variables were not significantly different. CONCLUSIONS: Intermittent antegrade warm blood cardioplegia results in less myocardial cell damage than cold crystalloid cardioplegia, as assessed by the release of cardiac-specific markers. This beneficial effect has only marginal clinical consequences. Normothermic bypass has no deleterious effect on end-organ function.     

Cold crystalloid versus warm blood cardioplegia for coronary artery bypass surgery.

PURPOSE: Intermittent cold crystalloid cardioplegia by antegrade route to arrest the heart for coronary artery bypass grafting (CABG) is a commonly used technique. The aim of this study is to compare the intermittent antegrade warm blood cardioplegia with cold crystalloid cardioplegia by means of measuring myocardial injury markers CKMB and troponin T. We also compared the results with antegrade and retrograde warm blood cardioplegia. MATERIALS AND METHODS: Patients (n=30) undergoing CABG were prospectively randomized into group 1 (n=10) which received cold crystalloid cardioplegia by antegrade route, group 2 (n=10) which received warm blood cardioplegia by antegrade route and group 3 (n=10) which received antegrade/retrograde warm blood cardioplegia. RESULTS: Preoperative and intraoperative variables were equal in all three groups. Control levels of troponin T and CKMB were in a normal range. Postoperative troponin T was significantly lower in group 3 compared to group 2 (p"=0.008") and to group 1 (p"=0.005"). CKMB is significantly higher in group 1 compared to group 2 (p"=0.013") and higher in group 2 than that in group 3 (p"=0.043"). CONCLUSION: Antegrade with retrograde warm blood cardioplegia is a simple delivery method. Troponin T and CKMB levels were significantly lower, suggesting that this offered better myocardial protection than antegrade cold crystalloid and warm blood cardioplegia. We recommend its wider use.     

Whole blood cardioplegia (minicardioplegia) reduces myocardial edema after ischemic injury and cardiopulmonary bypass

While blood:crystalloid cardioplegia is the clinical standard for patients undergoing cardiopulmonary bypass (CPB), it has been postulated that whole blood minicardioplegia may benefit the severely injured heart by reducing cardioplegic volume, thereby reducing myocardial edema. To test this hypothesis, we compared the cardioprotection of a popular 4:1 blood:crystalloid cardioplegia to whole blood minicardioplegia (WB) in a porcine model of acute myocardial ischemia. Yorkshire pigs (n = 20) were placed on atriofemoral bypass and subjected to 30 minutes of global normothermic ischemia. Animals were randomized to receive either 4:1 cold cardioplegia (n = 10) or WB cold cardioplegia (n = 10) delivered antegrade continuously for 90 minutes. Baseline (BL) echocardiographic determination of left ventricular mass (LVM) was compared within groups for cardiac edema (%) measured by histologic morphometrics. All (100%) animals receiving WB were successfully weaned off CPB, whereas only 40% of animals receiving 4:1 were successfully weaned off CPB. Cardiac edema percentage (p < .004) and LVM (p < .05) were significantly decreased in the WB group compared with 4:1. WB cardioplegia increases the number of hearts successfully weaned from CPB and decreases cardiac edema in our porcine model of acute myocardial ischemia. This finding implies whole blood cardioplegia may be more protective in a select group of patients undergoing extended CPB time by decreasing myocardial edema.     

单纯钾停跳氧合血持续灌注不降温心脏直视手术(附160例报告)

应用钾停跳、氧合血持续灌注心肌保护、不降温体外循环行心脏直视手术１６０例，手术均顺利，术后无低心排综合征、无严重心律失常发生。全组死亡２例（１．２５％）。部分病例进行了ＬＤＨ１／ＬＤＨ２、ＣＫ－ＭＢ及血清乳酸测定，与低温体外循环组比较无统计学明显差异（Ｐ＞０．０５）。作者认为，此方法临床效果满意，值得进一步研究、推广应用。     

Cold blood versus cold crystalloid cardioplegia: a prospective randomised study of 345 aortic valve patients

Objective: Although experimental studies have indicated that blood cardioplegia may be superior to crystalloid cardioplegia for myocardial protection, clinical data still remain uncertain. In a previous randomised study from our institution, including 1440 patients undergoing coronary artery bypass grafting (CABG), no beneficial effects of blood cardioplegia were seen in any relevant outcome variables. The investigation was therefore extended to a patient population having longer pump times and ischaemic periods. Methods: Over a 48-month period, all patients undergoing aortic valve replacement with or without CABG performed by two surgeons, were prospectively randomised to receive either intermittent cold retrograde blood cardioplegia (group B) or intermittent cold retrograde crystalloid cardioplegia (group C) during aortic cross-clamping. Results: A total of 345 patients aged 28–90 years (median, 72 years) entered the study (group B, n = 172, group C, n = 173). All relevant demographic and operative variables were similar for both groups. As for the clinical course, no statistically significant differences were seen concerning spontaneous sinus rhythm after aortic declamping, use of inotropic drugs, duration of ventilatory support, bleeding and rate of allogeneic blood transfusions, perioperative myocardial infarction, episodes of atrial fibrillation, stroke or minor neurological dysfunction, renal function, infections, physical rehabilitation or mortality. Further, in the patients with the longest ischaemic times, no statistically significant differences between the groups could be demonstrated. Conclusions: There were no indications that retrograde cold blood cardioplegia was superior to retrograde cold crystalloid cardioplegia patients undergoing aortic valve replacement, with or without CABG.     

Comparison between intermittent antegrade warm blood cardioplegia and cold crystalloid cardioplegia in patients performed reoperation for valvular heart disease

The purpose of this study was to compare the postoperative cardiac function and systemic effects between intermittent antegrade warm blood cardioplegia and cold crystalloid cardioplegia in patients performed reoperation for chronic acquired valvular heart disease. Group I consisted of 4 patients who underwent intermittent antegrade warm blood cardioplegia (MVR in 1, MVR + TAP in 2, DVR + TAP in 1), and Group II consisted of 5 patients who underwent intermittent antegrade cold crystalloid cardioplegia (MVR + TAP in 3, TVR in 2). There were no significant differences found between the two groups in operation time, perfusion time, aortic cross clamp time, spontaneous beating rate after declamping and reperfusion time. Also doses of inotropes required during weaning was almost the same for the both groups. But 24 hours after surgery, smaller doses of inotropes (4.4 +/- 2.1 gamma/kg/min) were required for Group 1, while larger doses (7.8 +/- 2.8 gamma/kg/min) were required for Group 2 (p < 0.05). As for the postoperative complications, none was noted in Group 1, while multiple organ failure in 2, hyperbilirubinemia in 2 and complete atrioventricular block in 1 patient was noted in Group 2. The above results suggest that, for reoperations of valvular heart disease, intermittent antegrade warm blood cardioplegia is a useful and reliable method with optimum myocardial protection as well as favorable systemic effects.     

Cold blood cardioplegia and warm cardioplegic reperfusion in heart transplantation

The major cause of early death after heart transplantation is graft failure. In 99 consecutive heart transplantations two protocols of myocardial protection were employed. In group 1 (n = 38) initial cold crystalloid cardioplegia combined with cold saline storage and peroperative surface cooling was used. In group 2 (n = 61) cold crystalloid cardioplegia was injected initially and cold blood cardioplegia (Buckberg) was infused every 30 min as soon as the graft arrived in the operating room. No surface cooling was used. Warm blood cardioplegic reperfusion was administered before removal of the aortic clamp. There were 8 early (within 30 days) deaths in group 1 and 6 in group 2 patients. In group 1 there were 5 cardiac deaths against 3 in group 2. Mean ischemic time was 153 +/- 37 min in group 1 and 158 +/- 51 min (p greater than 0.05) in group 2. The post-transplantation need for catecholamines was ten times higher in group 1 patients than in group 2. The first endomyocardial biopsy (after 1 week) showed cytologic lesions compatible with ischemia in 40% of group 1 and only 9% in group 2 patients. We conclude from this initial experience that intermittent cold blood cardioplegia and warm blood cardioplegic reperfusion are useful in heart transplantation in restoring the damage suffered by the graft during brain death and graft storage.     

Prospective clinical and biological comparison of three blood cardioplegia techniques in low-risk CABG patients: better is worse than good enough

OBJECTIVE: Three myocardial protection techniques were evaluated in a prospective, randomised trial during coronary artery bypass grafts in 69 patients. MATERIAL AND METHOD: Twenty seven patients received intermittent hyperkalaemic undiluted warm blood anterograde cardioplegia (AC), 21 received continuous hyperkalaemic undiluted warm blood retrograde cardioplegia (RC) and 21 received intermittent, hyperkalaemic, diluted cold blood (15 degrees C), anterograde cardioplegia (CC). Assessment criteria were clinical, laboratory and haemodynamic. RESULTS: Groups were homogeneous in terms of age, sex, cardiovascular risk factors, severity of coronary disease, preoperative ejection fraction, and number of bypass grafts performed. The oxygen extraction coefficient, and lactate and troponin production in the coronary sinus on aortic unclamping was not significantly different between the three groups. The base excess was -0.19+/-0.13 in the RC group, -0.18+/-0.52 in the AC group and -2.67+/-0.59 in the CC group (P<0.01 CC vs. AC and CC vs. RC). The priming volume was 1485+/-64 ml (CC), 1317+/-44 ml (RC) and 1318+/-30 ml (AC) (P<0.05 CC vs. AC and CC vs. RC). The haematocrit during CPB was 28.9+/-0.9 (CC), 32.5+/-0.8 (RC) and 32+/-0.7 (AC) (P<0.05 CC vs. AC and CC vs. RC). The volume of crystalloid delivered was 735+/-85 ml (CC), 362+/-67 ml (RC) and 357+/-105 ml (AC) (P<0.05 CC vs. AC and CC vs. RC). The incidence of ventricular fibrillation on aortic unclamping was 61.9% (CC), 9.5% (RC) and 0% (AC) (P<0.01 CC vs. AC and CC vs. RC). The transfusion rate, duration of intubation, postoperative troponin level, complication rate and mortality were not significantly different between the three groups. Haemodynamic parameters at H2, H4, H8 did not vary significantly between the three groups. CONCLUSION: These three techniques appear to be comparable in terms of myocardial protection. Anterograde cardioplegia ensures an identical degree of security to retrograde cardioplegia regardless of the coronary lesions, apart from redo lesions. CC requires greater haemodilution of the patients during CPB.     

The superiority of continuous cold blood cardioplegia in the metabolic protection of the hypertrophied human heart

The effects of sanguineous and asanguineous cardioplegia on the generation of myocardial acid in the hypertrophied human heart during aortic clamping and reflow were elucidated by continuous intraoperative monitoring of myocardial pH in 42 patients undergoing valve replacement, with or without coronary bypass. The patients were divided into three groups: Group I (n = 14) received intermittent crystalloid cardioplegia; group II (n = 14) received intermittent blood cardioplegia; and group III (n = 14) received continuous blood cardioplegia. The groups were matched according to six previously elucidated determinants of myocardial acidosis. Measurements were made of myocardial pH, hydrogen ion concentration ([H+]), and the difference in pH units between myocardial pH and the pH of neutrality of water at the corresponding temperature (delta pHn). Throughout aortic clamping, myocardial pH in groups I and II fell significantly by 0.46 +/- 0.08 and 0.15 +/- 0.07 units, respectively (p less than 0.001) between the groups). In contrast, myocardial pH remained statistically unchanged throughout aortic clamping in group III (p less than 0.001 compared to groups I and II). Similar relationships were observed in [H+] and delta pHn during aortic clamping. During the early reflow, myocardial acidosis was observed in all three groups and delta pHn in group III increased from -0.26 +/- 0.10 at the end of aortic clamping to -0.57 +/- 0.07 during reperfusion (p less than 0.03). Patients in groups II and III required significantly less inotropic and mechanical cardiac support than patients in group I (p = 0.017). Hence, although continuous blood cardioplegia does not completely prevent acid accumulation during reflow, it provides better metabolic protection of the hypertrophied human heart than either intermittent crystalloid or intermittent blood cardioplegia.     

Experience in the use and comparative assessment of the effectiveness of crystalloid and blood cardioplegia

Due to an increasing attention to questions of adequate protection of the myocardium and widely spread use of the method of blood cardioplegia the authors have made a comparative analysis of effectiveness of using 2 methods of cardioplegia--pharmacocrystalloid and cool blood antegrade cardioplegia: 34 patients were operated upon under conditions of extracorporeal blood circulation for aortic and mitral valve replacement. A comparison was made of 17 patients with intermittent antegrade cool crystalloid cardioplegia (group 1) and 17 patients with intermittent antegrade cold blood cardioplegia (group II). The results have shown that intermittent antegrade cool blood cardioplegia is a safe and effective method for myocardial protection during cardiopulmonary bypass.     

The effects of venous cannulation technique and cardioplegia type on plasma potassium concentration and arterial blood pressure during cardiopulmonary bypass.

The cannulation method and cardioplegia solution used during cardiopulmonary bypass (CPB) may both influence plasma potassium concentrations ([K+]) and mean arterial blood pressure (MAP). Bi-caval or right atrial cannulation methods are routinely used in conjunction with crystalloid or blood cardioplegia. We investigated the influence of cannulation method and cardioplegia solutions on plasma [K+] and MAP during cardiopulmonary bypass. Sixty consecutive patients undergoing elective coronary artery bypass grafting (CABG) using CPB were studied. They were randomly divided into three groups of 20 patients. Patients in Group A underwent bi-caval venous cannulation and received crystalloid cardioplegia. Group B patients underwent right atrial cannulation and received crystalloid cardioplegia. Group C patients underwent right atrial cannulation and received blood cardioplegia. In each case. cardioplegia was administered antegrade via the aortic root. Plasma [K+], MAP. and hemoglobin concentration (Hb) were measured over an 8-min period following cardioplegia administration (pilot studies indicated pressure changes occuring post cardioplegia administration up to this time). The combination of bi-caval cannulation and crystalloid cardioplegia (Group A) was associated with the least increase in plasma [K+] and no decrease in MAP. The maximum [K+] for this Group was 4.2 mmol/L (4.6% increase). The minimum mean pressure was 57 mmHg (13.6% increase). Both right atrial cannulation groups (B and C) showed a large rise in plasma [K+] and a decrease in MAP. Group B maximum [K+] was 5.2 mmol/L (27.5% increase). Group C was also 5.2 mmol/L (26.0% increase). Group C showed the largest pressure decrease, the minimum mean pressure was 45 mmHg (21.3% decrease). The Group B minimum mean pressure was 45 mmHg (8.7% decrease). Our results show that patients undergoing CPB operations who are deemed to be at increased risk of suffering adverse effects from hypotensive episodes may benefit from bicaval cannulation and caval snaring, in preference to right atrial cannulation. Crystalloid cardioplegia may be preferable to blood cardioplegia in these cases to maintain the MAP.     

Leukocyte-depleted blood cardioplegia reduces cardiac troponin T release in patients undergoing coronary artery bypass grafting.

OBJECTIVE: Activated neutrophils have been implicated in reperfusion injury of the myocardium. Leukocyte depletion at reperfusion may contribute to better myocardial protection during cardiac surgery. We tested the efficacy of leukocyte-depleted blood cardioplegia in reducing myocardial injury during coronary artery bypass grafting. METHODS: Subjects were 27 patients undergoing elective coronary artery bypass grafting divided into controls (perfused with nonfiltered blood cardioplegia, n = 12) and those undergoing leukocyte-depleted blood cardioplegia (n = 15). Oxygenated blood mixed with a potassium crystalloid cardioplegic solution was delivered through the aortic root at every 30 minutes during cardiac arrest and terminal warm blood was administered before aortic declamping in both groups. In leukocyte depletion, blood was filtered prior to the mixture with crystalloid solution in the cardioplegic reservoir. RESULTS: Patient profiles did not differ significantly between groups, nor did systemic leukocyte count during or after surgery despite more than 81% removal of leukocytes in cardioplegic delivery. No consistent differences between groups in creatine kinase or creatine kinase-MB were seen up to 18 hours after surgery. Peak troponin T levels were significantly lower in the leukocyte-depleted blood cardioplegia group (0.52 +/- 0.13 ng/ml), however, than in controls (3.85 +/- 0.85 ng/ml). CONCLUSION: We concluded that leukocyte-depleted blood cardioplegia reduces the release of cardiac troponin T in patients undergoing elective coronary artery bypass grafting and may produce better myocardial protection in patients with impaired cardiac function or a damaged myocardium.     

The relationship of myocardial stroke work to coronary flow velocity immediately after aortic valve replacement

BACKGROUND: The interrelations between myocardial stroke work and coronary flow velocity have not been fully defined during aortic valve replacement or with different cardioplegias. METHODS: Twenty-six patients (15 men age 63+/-13 years) who had elective isolated aortic valve replacement were studied by transesophageal Doppler echocardiography with simultaneous high fidelity left ventricular pressure. Fifteen patients received cold blood cardioplegia and 11 had warm blood cardioplegia. Myocardial stroke work and flow velocities in proximal left anterior descending coronary artery were quantified simultaneously before cardiopulmonary bypass and at 1, 6, 12, and 20 hours afterwards. RESULTS: Myocardial stroke work decreased postoperatively in both groups (160+/-19 versus 228+/-19 mJ/cm3 per minute, with cold blood cardioplegia; 135+/-22 versus 227+/-22 mJ/cm3 per minute with warm blood cardioplegia; both p<0.001 versus time, but p>0.05 versus cardioplegia, by two-way analysis of variance). Left anterior descending artery flow velocity-time integral per minute increased significantly in both groups (26.1+/-2.1 versus 15.0+/-2.1 m/min with cold blood cardioplegia; 32.8+/-2.5 versus 14.4+/-2.5 m/min with warm blood cardioplegia; both p<0.001 versus time, but p>0.05 versus cardioplegia). Thus, at 1 hour postoperatively the mJ x cm(-3) x m(-1) x min ratio of myocardial stroke work to left anterior descending artery flow velocity-time integral decreased significantly in both groups (4.3+/-1.6 versus 16.3+/-1.7 mJ x cm(-3) x m(-1) x min with warm blood cardioplegia, and 7.4+/-1.4 versus 17.9+/-1.4 J x cm(-3) x m(-1) x min with cold blood cardioplegia; both p<0.001 versus time). Warm blood cardioplegia was also associated with a lower mean ratio perioperatively than that with cold blood cardioplegia (7.8+/-0.9 versus 10.9+/-0.7 mJ x cm(-3) x m(-1) x min, p = 0.014). CONCLUSIONS: Coronary hyperemia occurs for at least 20 hours postoperatively when myocardial stoke work has decreased. The ratio of myocardial stroke work to coronary flow velocity appears to be more sensitive than either alone in differentiating the effect of warm versus cold blood cardioplegia.     

Adenoviral gene transfer to the heart during cardiopulmonary bypass: effect of myocardial protection technique on transgene expression.

OBJECTIVE: Adenoviral gene transfer to the arrested heart during cardiopulmonary bypass (CPB) is a novel method of allowing prolonged vector contact with the myocardium. In this model we investigated the importance of temperature, duration of arrest and cardioplegia on transgene expression. METHODS: First-generation adenoviral vector (1 x 10(12) total viral particles) containing the transgene for the human beta2-adrenoceptor (Adeno-beta(2)AR) or beta-galactosidase (Adeno-beta(gal)) was delivered to neonatal piglets via the proximal aorta, during simulated cardiac surgery, and allowed to dwell for the cross-clamp duration. Four treatment groups received Adeno-beta(2)AR. Groups A (n=4) and B (n=6) underwent cold crystalloid cardioplegia arrest for 10 and 30 min, respectively, Group C (n=5) underwent warm crystalloid cardioplegia arrest for 10 min, and Group D (n=5) underwent warm fibrillatory arrest for 10 min. Group E (n=6) received Adeno-beta(gal) and underwent cold crystalloid cardioplegia arrest (30 min). Animals were weaned off CPB and recovered for 2 days. Receptor density was assessed in membrane fractions using radioligand binding and compared using the Mann-Whitney U-test. RESULTS: Left ventricular transgene overexpression, as evidenced by elevated betaAR density, following Adeno-beta(2)AR treatment was greatest with cold cardioplegia (Group A 588+/-288.8 fmol/mg; P=0.002 and Group B 520+/-250.9 fmol/mg; P=0.01) versus control (Group E 109+/-8.4 fmol/mg). Overexpression also occurred with warm cardioplegia (Group C 274+/-69.5 fmol/mg; P=0.05) and ventricular fibrillation (Group D 215+/-48.4 fmol/mg; P=0.02) versus control. Comparison of the combined cold cardioplegia groups versus those treated with warm conditions showed a trend towards increased expression with cold conditions (P=0.1). Receptor density was also significantly increased in the right ventricle of animals in Group B (165+/-18.1 fmol/mg; P=0.03) and Group D (181+/-23.4 fmol/mg; P=0.02) versus control (Group E 118+/-5.8 fmol/mg). CONCLUSIONS: Cold crystalloid cardioplegia is not detrimental to gene transfer in vivo. In fact, there was a trend towards increased left ventricular transgene expression when the adenoviral vector was delivered following cold versus warm cardioplegia. Shorter periods of contact with the vector may reduce transgene overexpression. Therefore, gene transfer is possible during cardiac surgery with clinically used myocardial protection techniques.     

Myocardial protection with intermittent cold blood during aortic valve operation: antegrade versus retrograde delivery

BACKGROUND: Intermittent antegrade cold blood cardioplegia is superior to warm blood cardioplegia in patients who have aortic valve operation. This study compared the cardioprotective efficacy of intermittent antegrade and retrograde cold blood cardioplegia with emphasis on metabolic stress in the left and right ventricles. METHODS: Thirty-nine patients who had elective aortic valve replacement were prospectively randomly selected to receive intermittent antegrade or retrograde cold blood cardioplegia. Left and right ventricular biopsies were collected 5 minutes after institution of cardiopulmonary bypass and 20 minutes after cross-clamp removal and were used to determine metabolic changes. Metabolites (adenine nucleotides, amino acids, and lactate) were measured using high-powered liquid chromatography and enzymatic techniques. Serial measurement of troponin I release was also used as a marker of myocardial injury. RESULTS: Preoperative characteristics were similar between groups. There was no in-hospital mortality, and no differences were observed in postoperative complications. Preischemic concentration of taurine was significantly higher in left ventricular biopsies, whereas adenosine triphosphate tended to be lower in the left ventricle. At reperfusion adenosine triphosphate levels were significantly lower than preischemic levels in right but not left ventricles irrespective of the route of delivery. The alanine-glutamate ratio was significantly elevated in both ventricles. Myocardial injury as assessed by troponin I release was also significantly increased in both groups. CONCLUSIONS: Retrograde and antegrade intermittent cold blood cardioplegic techniques are associated with suboptimal myocardial protection. Metabolic stress was more pronounced in the right than the left ventricle irrespective of the cardioplegic route of delivery used.