Optical mapping of the pig heart in situ under artificial blood circulation.

The emergence of optical imaging has revolutionized the investigation of cardiac electrical activity and associated disorders in various cardiac pathologies. The electrical signals of the heart and the propagation pathways are crucial for elucidating the mechanisms of various cardiac pathological conditions, including arrhythmia. The synthesis of near-infrared voltage-sensitive dyes and the voltage sensitivity of the FDA-approved dye Cardiogreen have increased the importance of optical mapping (OM) as a prospective tool in clinical practice. We aimed to develop a method for the high-spatiotemporal-resolution OM of the large animal hearts in situ using di-4-ANBDQBS and Cardiogreen under patho/physiological conditions. OM was adapted to monitor cardiac electrical behaviour in an open-chest pig heart model with physiological or artificial blood circulation. We detail the methods and display the OM data obtained using di-4-ANBDQBS and Cardiogreen. Activation time, action potential duration, repolarization time and conduction velocity maps were constructed. The technique was applied to track cardiac electrical activity during regional ischaemia and arrhythmia. Our study is the first to apply high-spatiotemporal-resolution OM in the pig heart in situ to record cardiac electrical activity qualitatively under artificial blood perfusion. The use of an FDA-approved voltage-sensitive dye and artificial blood perfusion in a swine model, which is generally accepted as a valuable pre-clinical model, demonstrates the promise of OM for clinical application.

Effects of epidural anesthesia on intrathoracic blood volume and extravascular lung water during on-pump cardiac surgery.

BACKGROUND: The most important side effect of epidural anesthesia is hypotension with functional hypovolemia. Aggressive infusion therapy can reduce the hypotension effect. However, in conjunction with cardiopulmonary bypass, it can increase acute lung injury. We hypothesized that epidural anesthesia, by reducing cardiac sympathetic tonus, with subsequent better pulmonary flow, does not increase lung interstitial fluids. METHODS: Sixty patients undergoing coronary artery bypass graft (CABG) surgery with cardiopulmonary bypass (CPB) were randomized to combined general anesthesia with epidural anesthesia / analgesia, (EA) group, and to general anesthesia with i/v opiate analgesia, (GA) group. Patients in the EA group received a high thoracic epidural, preoperatively. Intraoperatively, 0.25% bupivacaine 8 mL/h was infused and general anesthesia with sevoflurane was followed by bupivacaine infusion for 48 hours postoperatively. General anesthesia in the GA group was with sevoflurane and fentanyl 10 - 12 microg/kg and analgesia with pethidinum 0.1 - 0.4 mg/kg i.v. postoperatively. Global end-diastolic volume index (GEDI), intrathoracic blood volume index (ITBI) and extravascular lung water index (ELWI) were measured before anesthesia, before CPB and 15, 60, 180, 600 min. and 24 hr after CPB. Duration of mechanical lung ventilation was registered in both groups. RESULTS: ITBI and GEDI were significantly higher in the EA group at all time points of measurement (ITBI 945.6+/-146.4 ml/m(2) and 870.6+/-146.5 ml/m( 2) vs. 1118+/-153.2 ml/m(2) and 1020+/-174.9 ml/m( 2); GEDI 720+/-96.19 ml/m(2) and 775.0+/-159.5 ml/m( 2) vs. 805.4+/-97.59 ml/m(2) and 888+/-117.3 ml/m( 2)). GEDI was significantly lower in the GA group compared with baseline (801.9+/-132.4 ml/m(2) vs. 695+/-169.2 mL/m(2)). ELWI was significantly higher in the GA group (7.233+/-1.35 ml/kg and 7.333+/-1.32 ml/kg vs. 8.533+/-1.45 ml/kg and 8.633+/-1.71 ml/kg), but without significant changes in the EA group. Duration of mechanical lung ventilation was shorter in the EA group (663.7+/-98.39 min. vs. 362.2+/-33.72 min.). CONCLUSIONS: Epidural anesthesia / analgesia does not increase interstitial lung fluids by increasing intrathoracic blood volume or the amount of infusion fluids in patients undergoing cardiac surgery under cardiopulmonary bypass. There is, also, a decreased duration of mechanical lung ventilation.

Atrial fibrillation and changes in serum and urinary electrolyte levels after coronary artery bypass grafting surgery.

OBJECTIVE: Our study was designed to assess the incidence of atrial fibrillation, changes in serum electrolyte concentrations and urinary electrolyte excretion following coronary artery bypass grafting surgery. MATERIAL AND METHODS: A total of 165 patients who underwent elective coronary artery bypass grafting surgery at the Department of Cardiac Surgery (Heart Center) during the period of 2004-2005 were enrolled. Serum K(+), Na(+), Mg(2+), Ca(2+), Cl(-), and P(-) concentrations were measured before cardiopulmonary bypass (CPB), on the arrival to an intensive care unit, and 15-18 hours after the surgery. Urinary excretion of K(+), Na(+), Mg(2+), Ca(2+), Cl(-), and P(-) was estimated 24 hours before the surgery, during the surgery, and 24 hours after the surgery. Cardiac rhythm was monitored throughout the study. All patients randomly were divided into the group 1 (n=55), which received magnesium sulphate infusion, and group 2 (n=110), which did not receive magnesium sulphate. RESULTS: The overall incidence of atrial fibrillation was 27.4%. The patients in the group 1 had significantly higher levels of serum magnesium before CPB and serum chloride after the surgery. Urinary magnesium and calcium excretion was significantly higher in the group 1 during and after the surgery. Before the surgery and 24 hours after the surgery, phosphate excretion was significantly higher in the group 1. CONCLUSIONS: The incidence of atrial fibrillation after myocardial revascularization surgery remains high (27.4%). Serum electrolyte concentrations after myocardial revascularization varied within normal ranges. Magnesium sulphate infusion did not decrease the rate of postoperative atrial fibrillation during the early postoperative period in normomagnesemic patients.

Hypertonic hydroxyethyl starch solution for hypovolaemia correction following heart surgery.

BACKGROUND: The aim of the study was to evaluate the effect of hypertonic NaCl hydroxyethyl starch solution on haemodynamics and cardiovascular parameters in the early postoperative period in patients for correction of hypovolaemia after heart surgery. METHODS: Eighty patients undergoing myocardial revascularisation at the Clinic of Cardiac Surgery of the Heart Centre (Kaunas University of Medicine) were randomly divided into two groups. The HyperHaes group (n = 40) received 250ml 7.2% NaCl/6% HES solution and the control Ringer's acetate group (n = 40) received placebo (500 ml Ringer's acetate solution) for volume correction after the surgery. RESULTS: After infusion of HyperHaes solution, cardiac index increased from 2.69 (0.7) to 3.52 (0.8) l/min/m2, systemic vascular resistance index, pulmonary vascular resistance index and the gradient between central and peripheral temperature decreased, and oxygen transport parameters improved. Ringer's group patients needed more intensive infusion therapy (4050.0 (1102.2) ml in the Ringer's group, 3513.7(762.5) ml in the HyperHaes group). During the first 24 hours postoperatively, diuresis was significantly higher in the HyperHaes group (3640.0 (1122.9) ml and 2736.0 (900.7) ml), total fluid balance was lower in HyperHaes group (1405.6 (1519.0) ml and 2718.3 (1508.0)ml, respectively). After the infusion of HyperHaes solution, no adverse events were noted. CONCLUSIONS: HyperHaes solution had a positive effect on haemodynamic parameters and microcirculation. Oxygen transport was more effective after HyperHaes solution infusion. Higher diuresis, lower need for the infusion therapy for the first 24 hours and lower total fluid balance were determined in the HyperHaes group. No adverse effects were observed after HyperHaes solution infusion.

Influence of aspirin or heparin on platelet function and postoperative blood loss after coronary artery bypass surgery.

The aim of the study was to assess the effect of aspirin or heparin pretreatment on platelet function and bleeding in the early postoperative period after coronary artery bypass grafting (CABG) surgery. Seventy-five male patients with coronary artery disease who underwent CABG with cardiopulmonary bypass (CPB) were studied. The patients were divided into three groups: Group 1 (n=25) included patients receiving aspirin pretreatment, Group 2 (n=22) received heparin pretreatment, and Group 3 (n=28) included patients who received no antiplatelet or anticoagulant pretreatment. Twenty-four hours after surgery, all patients were administered aspirin therapy that was continued throughout their hospitalization period. We assessed the following preoperative blood coagulation indices: activated partial thromboplastin time (aPTT), international normalized ratio (INR), and fibrinogen. We compared platelet count and platelet aggregation induced by adenosinediphosphate (ADP) before surgery, 1 h after surgery, 20 h after surgery and on the seventh postoperative day. We assessed drained blood loss within 20 postoperative hours. Preoperative blood coagulation indices did not differ among the groups. Platelet count was also similar. One hour after surgery, platelet count significantly decreased in all groups (p<0.001), after 20 postoperative hours it did not undergo any marked changes, and on the seventh postoperative day, it significantly increased in all groups (p<0.001). Before surgery, the lowest index of ADP-induced platelet aggregation was found in Group 1 (p<0.05). One hour after surgery, platelet aggregation significantly decreased in all groups, most markedly in Group 3 (p<0.001), yet after 20 h, its restitution tendency and a significant increase in all groups was noted. On the seventh day, a further increase in the statistical mean platelet aggregation value was noted in Groups 2 and 3. Comparison of platelet aggregation after 20 postoperative hours and on the seventh day after surgery revealed a significantly higher than 10% increase of the index in 32% of patients in Group 1 (p<0.05), 27.3% of patients in Group 2 (p<0.05) and in 35.7% of patients in Group 3 (p<0.001). The lowest statistically significant value of postoperative blood loss was noted in Group 2 (p<0.01). Our study has shown that aspirin or heparin pretreatment had no impact on the dynamics of platelet function in the early postoperative period after CABG. The lowest postoperative blood loss was noted in patients pretreated with heparin.

Myocardial protective effect of warm blood, tepid blood, and cold crystalloid cardioplegia in coronary artery bypass grafting surgery.

AIM: To compare the myocardial effects of cardioplegia by warm blood, tepid blood, and cold crystalloid during coronary artery bypass grafting (CABG). METHODS: Patients undergoing CABG surgery at Kaunas University Hospital between 2000 and 2004 were randomized into three groups (n=156), receiving a different method of cardioplegia. Intermittent antegrade warm blood cardioplegia was used in 51 patients, tepid blood cardioplegia in 50 patients, and cold crystalloid cardioplegia in 55 patients. Mitochondrial function, myocardial ultrastructure, troponin T, and hemodynamic and clinical data were analyzed after surgery. RESULTS: All cardioplegic methods similarly affected structural and functional properties of mitochondria and coupling of oxidative phosphorylation, and all lowered the capacity of mitochondria to synthesize ATP. Ultrastructure of myocytes showed slight to moderate injury in the cold crystalloid cardioplegia group. The concentration of troponin T was significantly lower in the warm blood cardioplegia group than in the tepid blood cardioplegia and cold crystalloid cardioplegia groups at 12 hours (0.8+/-0.1 ng/mL, 1.9+/-0.2 ng/mL, and 2.8+/-0.3 ng/mL, respectively; P<0.001) and 24 hours after surgery (1.0+/-0.1 ng/mL, 2.2+/-0.3 ng/mL, and 2.5+/-0.3 ng/mL, respectively; P<0.001). Echocardiographic examination after surgery revealed that the changes in the left ventricle diastolic function were similar in all groups, and that systolic function did not change. The warm blood cardioplegia group showed shorter duration of intubation and hospitalization. There were no differences in the need of catecholamine administration, incidence of complications, and duration of stay in the intensive care unit. CONCLUSIONS: Intermittent antegrade warm blood cardioplegia provides better myocardial protection during CABG surgery, as assessed by the lower release of troponin T, lower fluid balance, shorter duration of tracheal intubation and hospital stay.

Influence of residual blood autotransfused from cardiopulmonary bypass circuit on clinical outcome after cardiac surgery.

Autotransfusion of the residual blood from the cardiopulmonary bypass (CPB) circuit is considered to be one of the methods enabling reduction in the need for transfusion, the possible adverse effects of which are well known and documented. The aim of the study was to evaluate the effectiveness of the autologous autotransfusion of centrifuged red blood cells from the residual blood of the CPB circuit in patients following heart surgery. Three groups of patients who underwent heart surgery were examined. The first group (Group 1) consisted of 37 patients who received all of the residual blood in the bypass circuit after CPB (collected into sterile plastic bags) during the early postoperative period. The second group (Group 2) consisted of 45 patients who did not receive the residual blood following CPB. The third group (Group 3) consisted of 42 patients who underwent reinfusion of centrifuged red blood cells from the residual blood remaining in the CPB circuit during the early postoperative period. Hematocrit (Hct) values 12 hours after the operation were found to be higher in Group 3 compared with those of the first and the second groups (by 13.2% and 11.1%, respectively). Blood loss during the first 12 hours after the operation and during the time spent in the intensive care unit did not differ between the groups. The number of transfusions was significantly lower in Group 3 (28.57%) in comparison with that of Groups 1 and 2 (37.83% and 38.10%, respectively). The rate of infective complications in Group 3 was lower in comparison with both Group 1 and Group 2 (9.2% and 18.1%, respectively). The duration of in-hospital stay in Group 3 was 25.8% shorter than Group 1. We conclude that autotransfusion of centrifuged red blood cells processed from the residual blood of the CPB circuit after CPB was effective in increasing Hct values 12 hours postoperatively, reducing the need for donor blood product transfusions, the rate of infective complications and lenght of stay in hospital.

[Autotransfusion of red blood cell from cardiopulmonary bypass circuit blood after cardiac surgery]. / Eritrocitu mases, paruostos is dirbtines kraujo apytakos aparate likusio kraujo, panaudojimo tikslingumas ligoniams po sirdies operaciju.

OBJECTIVE: The aim of this study was to evaluate the effect of autologous centrifuged residual cardiopulmonary bypass blood on patients' hematocryte value, donor blood product requirements, postoperative blood loss, hospitalization time and the development of infective complications. MATERIAL AND METHODS: Patients undergoing coronary artery bypass grafting or/and mitral valve procedures were divided into 3 groups. In group I (37 pts.) patients received all blood salvaged from the extracorporeal circuit at the end of cardiopulmonary bypass. In group II (45 pts.) patients blood was not re-infused. In group III (42 pts.) the residual pump blood was collected from the bypass circuit and spun at 2.600 rpm for 10-15 min. The clear upper supernatant was discarded and the remaining concentrated red cells were re-infused back to the patient. RESULTS: In all three groups hematocryte value during the first hour and postoperative blood loss during the first 12 hours after operation was similar. A higher hematocryte value was found in patients of group III after 12 hours postoperatively as compared with group I and group II (13.2% and 11.1% respectively, p<0.05). Furthermore, 28.57% patients in the group III required a blood transfusion compared with 37.83% patients in the group I and 38.10% patients in the group II (p<0.05). Patients in the group III developed less infective complications as compared with the group II the group I (10.3% and 4.3% respectively). Hospitalization time in group III was decreased in 25.8% as compared with the group I. CONCLUSIONS: We found that autologous centrifuged residual cardiopulmonary bypass blood was useful in avoiding infective complications, decreasing need of donor blood product requirement and postoperative length of stay in the hospital. This method increases hematocryte value after 12 hours postoperatively.

[Evaluation of ultrastructural changes in the ischemic myocardium in surgically obtained biopsies of the left ventricle]. / Iseminiu miokardo ultrastrukturos pakitimu ivertinimas zmogaus kairiojo skilvelio bioptatuose, paimtuose kardiochirurginiu operaciju metu.

Electron microscopic evaluation of the degree of ischemic injury in diseased human hearts is a very useful tool in estimating the quality of any method of myocardial preservation. Ultrastructural alterations give accurate data in the clinical setting. Our semiquantitative scoring system was created considering existing evaluation systems and based on our own observations. Eight grades of ischemic injury were defined, ranging from 1 (normal ultrastructural appearance) to 8 (irreversible ischemic damage) with respect to integrity and swelling of mitochondria, nuclei, myofilaments, membranes, organelles and components, as well as extracellular structures.