Peculiarities of the Development of the Myocardial Infarction in ISIAH Rats.

We studied peculiarities of the development of myocardial infarction in rats with inherited stress-induced arterial hypertension (ISIAH rats). The control group consisted of Wistar rats. Occlusion of the left coronary artery (30 min) followed by reperfusion (120 min) was performed. The infarct size was determined relative to the risk zone by staining with 1% triphenyltetrazolium. BP, blood filling, and blood flow in the caudal vessels were measured. The infarct size was 31.5±3.0% of the risk zone in Wistar rats and 47.9±4.4% in ISIAH rats (p=0.026). No correlations of infarction size and BP or HR were found at the study stages. In ISIAH rats, local 30-min ischemia followed by 120-min reperfusion caused greater myocardial infarction that did not depend on BP or HR.

[Myocardial Infarction and Natural Defense Mechanisms: The Role of Norepinephrine Reuptake].

PURPOSE: to study effect of norepinephrine reuptake blockade in reperfusion period on size of infarct caused by local ischemia with and without ischemic pre- and postconditioning. MATERIAL AND METHODS: Wistar rats (n=46) were randomly divided into 6 groups. Group (gr) I (n=7) - 30 min occlusion of left coronary artery followed by 120 reperfusion; gr II (n=2) as in gr I +desipramine (0.8 mg/kg intravenously [i.v.]) at the start of reperfusion; gr III (n=6) - ischemic preconditioning before coronary artery occlusion; gr IV (n=7).

Myocardial serotonin during ischemia under conditions of ischemic preconditioning.

We studied the dynamics of interstitial serotonin during local myocardial ischemia under conditions of ischemic preconditioning in Wistar rats. Ischemic preconditioning increased serotonin content in the dialysate (p=0.003). During 30-min ischemia, ischemic preconditioning delayed serotonin increase just before the 20th min of ischemia. Ischemic preconditioning promoted short-term increase in the serotonin level in the myocardial interstitium but followed by prolonged ischemia, it delayed the accumulation of serotonin in the myocardial interstitium.

[Myocardial serotonin metabolism after local ischemia and ischemic precondition].

To determine the effect of ischemic preconditioning upon myocardial serotonin and 5-hydroxyindolacetic acid (5-HIAA) dynamic in myocardial ischemia and reperfusion. 28 male Wistar rats anesthetized with urethane were randomly divided into 2 groups. In the control group (n = 13) rats were subjected to 30 min coronary occlusion and subsequent 120 min reperfusion. In the ex- perimental group (n = 15) ischemic preconditioning (3 x 3 min ischemia + 3 x 3 min reperfusion) before prolonged ischemia was used. Myocardial interstitial serotonin and 5-HIAA were measured using a microdialysis technique. Myocardial serotonin and 5-HIAA significantly increased af- ter ischemic preconditioning (p = 0.00298; p = 0.00187). In prolonged ischemia interstitial serotonin level was lower in the experimental group vs. control up to 20 min of ischemia (p < 0.05). We conclude that ischemic preconditioning increases interstitial myocardial serotonin, but inhibit serotonin increase in subsequent prolonged myocardial ischemia. After 20 minutes of reperfusion the lack of correlation between serotonin and 5-HIAA levels appeared which may be the evidence of serotonin uptake activation.

Ischemic postconditioning and size of myocardial infarction during inhibition of norepinephrine reuptake.

We studied the effect of inhibition of norepinephrine reuptake during the reperfusion period on the size of infarction zone after focal myocardial ischemia and under conditions of ischemic postconditioning. In groups 1 and 2, 30-min occlusion of the left coronary artery followed by 120-min reperfusion was performed. In groups 3 and 4, ischemia was followed by ischemic postconditioning (six 10-sec occlusions alternating with 10-sec reperfusions). Ringer solution (1 ml, groups 1 and 3) and desipramine (0.8 mg/kg, groups 2 and 4) were injected intravenously at the beginning of reperfusion. The area of myocardial infarction in group 1 was 32.0±3.1% of the area of the risk zone; in groups 2, 3, and 4 the corresponding value was 46.1±3.4% (p=0.006), 22.2±2.6% (p=0.028), and 50.3±3.1% (p=0.018), respectively. It was shown that inhibition of norepinephrine reuptake in the early reperfusion period after ischemia increased myocardial injury and abolished the protective effect of ischemic postconditioning.

Inhibition of norepinephrine reuptake and size of myocardial infarction during focal ischemia and after preconditioning.

Experiments on rats showed that blockade of norepinephrine reuptake in the early reperfusion period after focal myocardial ischemia aggravates myocardial injury and abolishes the protective effect of ischemic preconditioning.

[Ischemic preconditioning and metabolism of myocardial adrenaline].

We implanted under urethane narcosis microdialysis probes into myocardium of Wistar rats. In experimental group we used ischemic preconditioning. After this left descending coronary artery was occluded for 60 minutes and then reperfused for 60 min. In control group prolonged occlusion was preceded by 30 min of rest. Significant elevation of noradrenaline concentration in myocardial interstitium was noted at 20th and 10th minutes of testing ischemia in experimental and control groups respectively. From 20th minute to the termination of occlusion noradrenaline concentration in myocardial in animals of control group was significantly higher than that in preconditioned animals. Concentration of dihydroxyphenylglycol in interstitium reflecting noradrenaline metabolism in axoplasm fell during ischemia and rose when reperfusion was started. Elevation of dihydroxyphenylglycol was statistically significant compared with both baseline level and control (p<0.005) practically at all stages of reperfusion. Thus ischemic preconditioning inhibits effectively noradrenaline accumulation in myocardial interstitium during prolonged ischemia. After ischemic preconditioning normal mechanism of noradrenaline reuptake functions longer however because of impaired storage in vesicles substantial part of noradrenaline remains in free state in axoplasm to be subjected to deamination with participation of monoamine oxidase.

[Uptake1 inibition in reperfusion: noradrenalin dynamic and myocardiola infraction size].

To determine the effect of uptake 1 inhibition in reperfusion after myocardial ischcmia upon noradrenalin dynamic and myocardial infarction size, 14 male Wistar rats anesthetized with urethane were randomly divided into 2 groups and subjected to 30 min coronary occlusion and subsequent 120 min reperfusion. In control group (n = 7) 1 ml of Ringer's solution was administered intravenously at the beginning of reperfusion. In experimental group (n = 7) instead of Ringer's solution 0.8 mg/kg of desipramine was used. Myocardial interstitial noradrenalin levels were measured using a microdialysis technique. Infarction size was determined by triphenyltetrazolium chloride staining and was related to the area at risk. Desipramine increased infraction size from 32.0 +/- 3.1 % (control group) to 46.1 +/- 3.4% (p = 0.06). Interstitial noradrenalin in experimental group did not decrease during 120 min reperfusion (p < 0.05 vs. control). The data obtained suggest that uptake 1 inhibition in reperfusion after myocardial ischemia increases myocardial infarction size through increased interstitial noradrenalin.

[Role of norepinephrine in myocardial ischemia and ischemic preconditioning].

A brief preceding ischemia-reperfusion can reduce infarct size; this is known as ischemic preconditioning. During myocardial ischemia, massive norepinephrine is released from the cardiac sympathetic nerve terminals, reflecting the sympathetic nerve injury, and producing myocardial damage. However norepinephrine participates in myocardial protection during ischemia since its depletion in nerve terminals prevents ischemic preconditioning, and exogenous norepinephrine mimics ischemic preconditioning. Multiple-valued role of norepinephrine in myocardial ischemia, and ischemic preconditioning is discussed in review.

[Noradrenaline dynamics in prolonged ischemia after ischemic preconditioning].

AIM OF THE STUDY: To determine the effects of two-staged ischemic preconditioning on myocardial noradrenaline in prolonged ischemia and reperfusion. METHODS: Thirty-two male Wistar rats anesthetised with urethane randomly divided into 2 groups: group 1 (ischemic preconditioning group, n = 16), and group 2 (control, n = 16). Myocardial interstitial noradrenaline levels were measured using a microdialysis technique. Ischemic preconditioning was elicited by two episodes: 5 min of ischemia and 10 min of reperfusion. The intermittent occlusions were followed by prolonged occlusion (60 min) and reperfusion (60 min). RESULTS: An increase in interstitial noradrenaline was observed in 10 min of prolonged ischemia in group 2, and in 20 min in group 1. After 20 min of myocardial ischemia there was a significant difference between groups (p < 0.05) in interstitial noradrenaline levels. In control group, it was 60% higher. In reperfusion, noradrenaline levels decreased markedly in group 1. CONCLUSION: We suggest that ischemic preconditioning by two episodes: 5-min ischemia and 10-min reperfusion prevents excessive noradrenaline interstitial accumulation, perhaps, through protection of physiological uptake I carrier.

[The effect of surgery with cardiopulmonary bypass on oxygen transport in elderly patients with ischemic heart disease].

In a clinical trial, 103 patients undergoing coronary artery bypass grafting from May, 1999, to December, 2001 with hypothermic cardiopulmonary bypass (CPB) were retrospectively assigned to one of two groups: group I (n = 45)--patients 65 years of age and older (68.0 +/- 0.5), group II (n = 58)--patients 45-50 years of age (48.2 +/- 0.2). The following parameters were recorded: haemodynamic--with thermodilution method (SMU--612, Hellige), blood gases (OMNI-6, Austria). Measurements were performed 7 times: (1) before surgery, (2) before CPB, (3) after CPB, (4, 5, 6, 7)--1, 3, 9, 12 hours after surgery. Indexes of oxygen delivery and consumption, oxygen utilization coefficient and anion gap were calculated. Obtained results were statistically analyzed using appropriate t-test and chi2-test for categorical variables. Data are expressed as mean +/- SE. There were no significant differences between the groups in all stages of examination, p > 0.05. In elderly group both oxygen delivery and consumption were lower then in younger one, thus the coefficient of oxygen utilization did not differ between groups. Therefore the surgery with CPB seems to be inrelated to adverse changes on oxygen transport in elderly patients, and its dynamic was similar in patients over 65 years of age and younger group.

[Effects of the parameters of washing in Haemonetics Cell Saver 5 on the quality of the obtained erythrocyte mass at different rates of centrifuge rotation].

The aim of the investigation was to study effectiveness of washing autoblood by Cell Saver 5 (Haemonetics ) device in using different rates of washing and centrifuging. Autoblood was washed with 1000 ml 0.9% NaCl with different rates (500, 800 and 1000 ml/min) at different rates of centrifuge (5650 r/min and 4350 r/min). It was shown that Haemonetics Cell Saver 5 secured the optimum composition of the end product when using high rates of washing (800 and 1000 ml/min) and standard rate of the centrifuge rotation (5650 r/min).

[The cardiac performance recovery pattern and central hemodynamics in patients with coronary heart disease during coronary bypass surgery under extracorporeal circulation].

Central hemodynamic parameters were retrospectively studied in 284 patients. After aortic declamping, sinus rhythm spontaneously restored in 179 patients (Group 1), ventricular fibrillation occurred in 105 (Group 2). The preoperative parameters were similar in both groups. The number of grafts and the time of aortic clamping and cardiopulmonary bypass (CPB) were higher in Group 1. In the groups, the volume of cardioplegic solution and the average dose of phenylephrine and nitroglycerin per perfusion did not differ. After CPB, the values of cardiac output (CO) and cardiac index (CI) were significantly higher in Group 1 than in Group 2. At the end of an operation and 3 hours after its termination, there were no differences between two groups. Twelve hours after surgery, cardiac output and systolic blood pressure were significantly higher in Group 1. Following 24 hours of surgery, heart rate was significantly greater in Group 1 than in Group 2 After surgery, all hemodynamic parameters were within normal physiological values. The mean duration and the degree of inotropic support did not differ in the groups. The incidence of atrial fibrillation, perioperative myocardial infarction, and low cardiac output syndrome were comparable in both groups. Thus, various modes of cardiac performance recovery affect perioperative hemodynamics; however, this impact is insignificant and does not make management policy be changed in such patients. After aortic declamping, ventricular fibrillation requiring for defibrillation is not a clinical sensitive factor that negatively affects the intra- and postoperative period.

[Characteristic features of allogenic transfusions in elderly patients with ischemic heart disease in operations under conditions of extracorporeal circulation and using cell saver].

It was shown that in spite of using different methods of saving the autologous patient's blood, cell saver included, in elderly patients operated upon under conditions of extracorporeal circulation the frequency and volume of allogenic transfusions was higher as compared with the younger patients, in elderly women the allogenic transfusions being necessary more frequently.

[The oxygen-transport function of blood in reconstructive operations on the aorto-femoral segment and application of high molecular hydroxyethyl starch].

The prospective randomized investigation included 71 patients with obliterating atherosclerosis of the lower extremities with chronic ischemia. Planned operations of aorto-bifemoral shunts were made. Patients of the first group (n=43) were treated by infusion therapy including solutions of colloids and crystalloids. In the second group a solution of high molecular hydroxyethyl starch was used in addition to colloids and crystalloids. Transfusion of the allogenic components of blood was made in the both groups according to the indications. The parameters of the oxygen-transport function of blood were studied before initial narcosis, under conditions of general anesthesia before the beginning of operation, in 60 minutes of reperfusion after finishing the aorto-femoral shunting, and in a day after operation. It was shown that using the solution of high molecular hydroxyethyl starch promoted the elevated level of the delivery and consumption of oxygen as compared with the standard infusion-transfusion therapy which is explained by the predominantly hemodynamic component of the oxygen transport.

[Low doses of aprotinin in reducing blood loss and allogenic transfusions in operation under conditions of extracorporeal circulation with using cell saver].

A blind prospective randomized investigation included 109 patients with ischemic heart disease undergoing operations of coronary shunting under conditions of extracorporeal circulation. It was shown that aprotinin in the dose of 3 ppm KIU in operations of coronary shunting under conditions of reserving autoblood, extracorporeal circulation and using cell saver facilitates reducing postoperative blood loss, but does not lead to less frequent allogenic transfusions.

[Aprotinin in the correction of the hemodynamic syndrome of systemic inflammatory response in surgeries with extracorporeal circulation]. / Aprotinin v korrektsii gemodinamicheskogo syndroma sistemnogo vospalitel'nogo otveta pri operatsiiakh s iskusstvennym krovoobrashcheniem.

Seventy-three patients with ischemic heart disease (IHD), who underwent coronary artery bypass grafting with artificial circulation (AC), were examined within a prospective randomized study. The patients were randomized between three groups. The group-1 patients were administered trasilol (T) according to the below scheme: 1 mln KIU from patient's admission to the surgery room to the time the skin incision is made plus 2 mln KIU from the moment the surgical approach is preformed to the beginning of AC. KIU was added to the artificial circulation apparatus (ACA) when it was initially filled (total T dose of 6 min KIU). T was administered in the group-2 patients similarly to the scheme used in group 1; however, it was not added to the ACA (total T dose of 3 mln KIU). And T was not used at all in the group-3 patients. The dose of mezatone administered at the AC stage was reliably higher in groups 3 and 4 versus group 1 (p < 0.05 and p < 0.1, respectively). Doses of mezatone that were used for the vasopressin management did not differ significantly between the groups after surgery. A statistically more significant increase of stroke index (deltaSI) and a decrease of general peripheral vascular resistance (GPVR--deltaGPVR) were registered in 12 hours after surgery in group 3 versus group 1, p < 0.05 and p < 0.01, respectively. The negative deltaGPRV was also more pronounced versus the parameters observed in group 1 and 2 (p < 0.01 and p < 0.02, respectively). Therefore, T, when used at 6 mln KIU in AC, provides for a smaller-scope vasopressin management in AC. And, when it is used before AC at 3 mln KIU, T dose not diminish the dose of vasopressin management in AC. The intraoperative use of T (6 or 3 mln KIU) arrests a pronounced decreased postoperative deltaGPRVR and an increased postoperative CI irrespective of a dose.

[Efficacy of intraoperative reservation of auto-blood in surgical treatment of ischemic heart disease using Cell-Saver]. / Effektivnost' intraoperatsionnogo rezervirovaniia autokrovi pri khirurgicheskom lechenii ishemicheskoi bolezni serdtsa v usloviiakh primeneniia "Cell-Saver".

A prospective randomized study was made for 109 patients with ischemic heart disease (IHD) after coronary artery bypass grafting (CABG) with artificial blood circulation. Fifty-five (55) patients (Group 1--controls) were operated on without intraoperative autoblood reservation. Blood was sampled (7.6 +/- 0.3 ml/kg) at the surgery beginning in 54 patients (Group 2) with its subsequent transfusion after the artificial blood circulation was over. Cell saver was used in all patients intraoperatively (and, depending on indications--postoperatively). The dynamic content of hemoglobin, counts of erythrocytes, hematocrit parameters as well as the content of blood platelets and the content of blood-plasma total protein were examined postoperatively. The intraoperative autoblood reservation (7-8 ml/kg) made in CABG with cell saver for IHD patients maintains higher values of hemoglobin, erythrocyte counts and of hematocrit parameters during the early postoperative period, however, it does not reduce the frequency use or transfusion volume of donor blood.

[Oxygen transport and hemodynamic reactions in ischemic heart disease patients when reserving and reinfusing massive volumes of autoblood]. / Transport kisloroda i gemodinamicheskie reaktsii bol'nykh s ishemicheskoi bolezn'iu serdtsa pri rezervirovanii i reinfuzii massivnykh ob"emov autokrovi.

The prospective randomized investigation was carried out in 61 patients with ischemic heart disease who were subjected to planned operations of coronary shunting under conditions of extracorporeal circulation. In the first group of patients autoblood as much as 24% of the calculated circulating blood volume (CBV) was reserved at the stage of isolation of the mammary artery, before systemic heparinization. The volume of the reserved blood of the patients of the second group was about 12% of CBV. It was shown that the reserving and reinfusion of massive (about 24% of CBV) volumes of autoblood in surgical treatment of ischemic heart disease under conditions of extracorporeal circulation failed to cause a substantial change of indices of central hemodynamics as compared to the reserving and reinfusion of autoblood in volume of about 12% of CBV.

[Blood-saving effectiveness of preoperative reservation of autoblood for surgical treatment of ischemic heart disease]. / Krovosberegaiushchaia éffektivnost' dooperatsionnogo rezervirovaniia autokrovi pri khirurgicheskom lechenii ishemicheskoi bolezni serdtsa.

A randomized prospective investigation included 143 patients (coronary shunting for IHD under conditions of extracorporeal circulation--EC). In 55 patients exfusion of autoblood followed by its transfusion after finishing EC was made before operation in 88 patients. A cell saver was used in all the patients from the moment of cutting the skin for the collection of blood and for the collection of perfusate left in the EC apparatus after finishing EC and for autotransfusion of the drainage fluid released after operation. The preoperative reservation of autoblood in patients with IHD for operations of coronary bypass under conditions of EC and using the cell saver gives higher values of hemoglobin and erythrocytes by the moment of discharge of the patients from the hospital, but non the less does not reduce the frequency of using homologous blood.