[Estimation of myocardial damage after cardiac surgery by myosin light chain I and troponin T].

The purpose of the study was to test cardiac myosin light chain I (MLCI) and troponin T (TNT) as markers of myocardial damage after heart surgery. Forty-three patients undergoing cardiac surgery were arbitrarily divided into three groups according to the creatine kinase MB isoenzyme (CK-MB) levels and postoperative electrocardiogram (ECG) changes. Group 1: CK MB > 100 micrograms/l and Infarction pattern changes in ECG (Infarction): Group 2: CK-MB < 100 micrograms/l and no ECG changes (minimal myocardial damage). Group 3: CK-MB > 100 micrograms/l or non specific ECG changes (myocardial injury). MLCI levels showed strong correlations with TNT levels after the operation. The peak MLCI and TNT levels in group 1 were significantly higher than in group 2. The peak MLCI in group 1 was significantly higher than in group 3. TNT showed different patterns in the Infarction and Injury groups. The study showed that MLCI and TNT estimation could evaluate myocardial damage over several postoperative days. TNT estimation could identify myocardial damage earlier than MLCI, however MLCI could discriminate perioperative infarction better than TNT.

Assessment of myocardial damage by circulating cardiac myosin light chain I after heart transplantation.

The purpose of this study was to evaluate the cardiac damage by cardiac myosin light chain I after transplantation. This study included 30 patients who underwent cardiac operations and who were divided into three groups. These groups consisted of (1) control group, 15 valvular patients without coronary disease (no electrocardiography changes and creatine kinase MB isoenzyme of 100 micrograms/L or less); (2) infarction group, eight patients (six coronary bypass and two valvular patients with perioperative infarction pattern in the electrocardiography and creatine kinase MB isoenzyme of 100 micrograms/L or more; and (3) transplantation group, seven transplant patients (six heart and one heart-lung). The peak cardiac myosin light chain I value in the transplantation group (32.9 +/- 3.4 micrograms/L) was comparable to the infarction group (27.6 +/- 2.6 micrograms/L), and both of them were significantly higher than the control group (9.2 +/- 0.9 micrograms/L) (p < 0.01). Peak cardiac myosin light chain I levels in the control and transplantation groups correlated with the ischemic time (r = 0.48, p < 0.05 and r = 0.67, p < 0.05, respectively). The total dose of dopamine in the transplantation group correlated with the peak cardiac myosin light chain I (r = 0.67, p < 0.05), and with the cardiac myosin light chain I value on day 7 (r = 0.88, p < 0.01). This study suggests that circulating cardiac myosin light chain I estimations are useful to evaluate myocardial damage after transplantation during postoperative week 1.

Effect of reduced aprotinin dosage on blood loss and use of blood products in patients undergoing cardiopulmonary bypass.

High-dose aprotinin reduces bleeding after cardiac surgery, but has also evoked concern with regard to potential side effects and hospital costs. To evaluate the effects of reduced-dose aprotinin on blood loss and need for blood transfusion, 40 patients undergoing myocardial revascularization were studied (double-blind, placebo-controlled). Postoperative bleeding was reduced by 40% and erythrocyte infusion by 85% in the group given 3 x 10(6) KIU aprotinin (1 x 10(6) as a loading dose before cardiopulmonary bypass, 1 x 10(6) in the priming volume and 2.5 x 10(5)/hour intraoperatively) Aprotinin concentrations during the operation were monitored and maintained above the required level. There were no adverse effects of the drug. Hospital expenditure on blood products was reduced by 51% when aprotinin was used. Our study suggests that aprotinin in reduced dosage diminishes bleeding and requirements for blood products, and that it should be given before, during and after cardiopulmonary bypass.

The influence of heparin-coated and uncoated extracorporeal circuits on blood rheology during cardiac surgery.

The effect of heparin-coated perfusion circuits on blood trauma during clinical cardiopulmonary bypass (CPB) was studied in order to find out if traumatic changes in the blood could be minimized. Twenty-four patients undergoing coronary artery bypass surgery were randomized prospectively to CPB with heparin-coated circuits (HCC) or non-coated circuits (NCC). The trauma to blood was assessed by measuring damage to blood cells by estimating red and white cell rheology changes. These were measured as red cell filtration rate (RFR) and white cell filtration rate (WFR) using standard microfiltration methods. Furthermore, changes in plasma hemoglobin (P-Hb), whole blood and plasma viscosity were simultaneously assessed. The RFR was significantly reduced in both groups during CPB by 10% in the HCC and 32% in the NCC groups (p less than 0.01). When comparing the HCC and NCC groups, a significant difference was first seen after 30 minutes of bypass (p less than 0.05) and increased at the end of CPB (p less than 0.01). Similar results were seen regarding WFR (15% and 36%, p less than 0.01). After 30 minutes of bypass, a significant difference was seen between HCC and NCC groups (p less than 0.05). Furthermore, a significant increase in P-Hb levels were seen during CPB in both patient groups. At the end of CPB, there was a significant difference in P-Hb levels (HCC 305+/-90 mg/L; NCC 455+/-78 mg/L, p less than 0.01) when comparing the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

High-dose aprotinin (trasylol) in reducing bleeding and protecting lung function in potential bleeders undergoing cardiopulmonary bypass.

Intraoperative high-dose aprotinin during cardiopulmonary bypass was used to investigate if high-risk bleeders could be changed to bleed normally or less as well as see if aprotinin could preserve lung function. Eleven matched controls were compared with eleven aprotinin patients taking warfarin or aspirin preoperatively. The mean (+/- SEM) 12-h and 24-h postoperative amount of bleeding, volume of blood product transfusion and hemoglobin reduction in the aprotinin group were 328 +/- 45 ml, 418 +/- 63 ml, 341 +/- 99 ml and 1.8 +/- 0.5 g% respectively, which were significantly lower than the respective values of 716 +/- 86 ml (P less than 0.01), 1,029 +/- 115 ml (P less than 0.01), 985 +/- 294 ml (P less than 0.05) and 4.1 +/- 0.4 g% (P less than 0.02) in the controls. There was a 65% blood-saving effect by aprotinin in this study. The hypercapnea rate was 45% in the treated patients, and 82% (P less than 0.05) in the controls reflecting better preservation of pulmonary diffusion function which is clinically important following major surgery.

Are leukocytosis and lipid peroxidation involved in ischemic or reperfusion injury in cardiac surgery?

We have studied the hypothesis that free-radical generation during cardiac surgery could explain partly the pathophysiology of ischemic or reperfusion injury during cardiopulmonary bypass (CPB). Ten patients undergoing cardiac surgery using CPB were prospectively studied. Malondialdehyde (MDA) was measured as a marker of free-radical-induced lipid peroxidation (LPO) using the thiobarbituric acid method, and leukocytes were counted during ischemia and reperfusion. Both MDA and leukocytes increased significantly, especially after starting reperfusion. There was significant correlation between LPO and leukocytosis (r = 0.8, p less than 0.005). It is concluded that free radicals generated during ischemia and reperfusion lead to an increase of LPO, which is shown for the first time to be associated with leukocytosis in cardiac surgical patients. The implication of this observation is of importance for the treatment strategy using free-radical scavengers in reducing the harmful effects of ischemia and reperfusion in cardiac surgery.

Influence of allopurinol on cardiac complications in open heart operations.

During cardiac operations, the heart is subjected to total ischemia and reperfusion, causing serious operative and postoperative complications such as arrhythmias, heart failure, and infarctions that may be partly due to free radical generation. Thus, allopurinol was tested to see if it could reduce cardiac complications during open heart operations. Ninety patients undergoing elective coronary artery bypass grafting were studied prospectively. Fortyfive patients were treated with allopurinol and 45 patients acted as controls. Treatment requiring arrhythmias in the allopurinol group was 6.6% compared with 33.3% in the control group (p less than 0.01). The percentage of patients requiring inotropes was significantly lower in the allopurinol group than in the control group (4.4% versus 26.6%; p less than 0.01). Perioperative myocardial infarction did not occur in the allopurinol group but was seen in 8 patients (17.7%) in the control group. Intraaortic balloon pumping was used in 5 control patients (11.1%) but not in the allopurinol group. This study shows that allopurinol decreases significantly the incidence of cardiac complications in open heart operations.

The influence of age on the durability of Carpentier-Edwards biological valves. Thirteen years follow-up.

Two hundred and ninety-nine patients received 325 Carpentier-Edwards biological valves from April 1976 to April 1982. Valves were placed in the following positions: 150 aortic (AVR), 120 mitral (MVR), 26 multiple (MR), 2 pulmonary (PR) and 1 tricuspid (TR). The mean age was 54.7 years. The total follow-up time was 2545 patient-years. Patients were divided into different age groups: less than 40, 40-49, 50-59, 60-69 and greater than 70 years and were followed-up for reoperations and tissue failure. Ninety-three operations were performed in 91 patients (30.5%) for valve related dysfunctions. The main cause of reoperation was primary tissue failure (85%). The respective incidence and risk of reoperation in the different age groups were 51.5% and 5%, 41.5% and 4%, 32% and 3%, 18% and 2.5%, and 0% for greater than 70 years of age. The risk of reoperation decreased significantly with increasing age (P less than 0.05). The respective incidence and risk of tissue failure in the age groups were 43.8% and 4.1%, 35% and 4%, 27.3% and 3.2%, and 17.2%, 2.4% and 0%. The freedom from reoperation and tissue failure was significantly higher in the older patient (greater than 60 years) compared to the younger patients (less than 60 years). The commonest cause of failure in young patients was calcification, while in older patients it was cusp rupture. Comparing aortic and mitral bioprostheses in the different age groups showed no difference between these valves in patients less than 50 years of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Trauma metabolism and the heart. Uptake of substrates and effects of insulin early after cardiac operations.

In a controlled, randomized study the myocardial uptake/release of individual free fatty acids, glucose, lactate, pyruvate, alanine, and glycerol was studied 1 hour after completion of coronary operations. The effects of insulin were evaluated by means of a hyperinsulinemic "clamp" technique. No significant uptake of free fatty acids was found despite markedly elevated arterial concentrations (mean +/- standard error of the mean, 2.01 +/- 0.19 mmol.L-1), oleic acid, together with palmitic and linoleic acid, constituting 80% of the total plasma free fatty acid level. Insulin treatment (1 unit.kg bw-1.hr-1) prevented a further increase of the plasma free fatty acid level, observed concomitantly in the control group. Insulin affected all individual free fatty acids similarly. Changes in plasma free fatty acid levels occurring during the study and the corresponding myocardial uptake correlated (rS = 0.50 to 0.81). No significant uptake or release of glucose, lactate pyruvate, and glycerol occurred, whereas a myocardial release of alanine was seen. The heart and the concomitant leg uptake/release of glucose (rS = 0.40, p less than 0.05) and lactate (rS = 0.67, p less than 0.01) correlated. A substantial uptake of glucose was achieved and a more positive myocardial balance was obtained for alanine, lactate, and pyruvate with insulin. The changes in heart and the concomitant leg uptake/release correlated (glucose, rS = 0.62, p less than 0.01; lactate, rS = 0.64, p less than 0.01; pyruvate, rS = 0.71, p less than 0.01). It is concluded that the myocardial uptake of substrates during the first hours after coronary surgery is markedly abnormal with no uptake of free fatty acids or carbohydrates. These changes can be explained to some extent by the insulin resistance of trauma metabolism and can be modified by insulin treatment.

Blood cell filtrability: reference values and clinical applications.

In 500 healthy individuals cell deformability, expressed as cell filtration rate in microliters/s was studied with a microcirculation method in order to determine reference values for this method for various age groups in adults. The overall normal red cell filtration rate (RFR) value in healthy individuals was 69 +/- 11 microliters/s. When one compared the age groups 20-29 and 60-69 years, the reductions for RFR, white cell filtration rate (WFR), plasma-white cell filtration rate (P-WFR) and whole-blood filtration RATE (WBFR) was 26 +/- 3 (p less than 0.01), 32% +/- 5 (p less than 0.01), 28% +/- 4 (p less than 0.01) and 28% +/- (p less than 0.01) respectively. The reduction of RFR was graded into four clinical classes (GCTA = Gothenburg Cardio-Thoracic Association); I = 1-24%, II = 25-49%, III = 50-74%, IV = 75-100%, class I with lowest and class IV with highest reductions. Significant reductions in the mean RFR were noted in patients undergoing heart surgery (36% +/- 3, P less than 0.01, class II), patients with cardiac arrest (55% +/- 5, p less than 0.01, class III), occlusive arterial disease (58% +/- 6, p less than 0.001, class III) diabetes (45% +/- 5, p less than 0.01, class II). None of the patients had a normal RFR value. This study demonstrated a loss of cell deformability with age and disease.

Control of intraoperative hypertension with isoflurane in patients with coronary artery disease: effects on regional myocardial blood flow and metabolism.

The effect of isoflurane on regional myocardial metabolism and blood flow, when used as an adjunct to fentanyl-nitrous oxide anesthesia, to control intraoperative hypertension was investigated. Twenty-two patients with two- or three-vessel coronary artery disease with an ejection fraction greater than 0.5 and on beta-blockers up to the morning of surgery were studied during elective coronary artery by-pass grafting. Systemic and pulmonary hemodynamics, and regional (great cardiac vein, GCVF) myocardial blood flow and myocardial metabolic parameters were measured. In 10 patients, both GCVF and global (coronary sinus, CSF) myocardial blood flows were recorded. Measurements were made 1) after induction of anesthesia but prior to skin incision, 2) during sternotomy, and 3) during isoflurane administration after its use to reduce arterial pressure to the presternotomy level. The increase in systemic arterial pressure during sternotomy was due to an increase in systemic vascular resistance accompanied by increases in heart rate, pulmonary capillary wedge pressure, (PCWP) regional myocardial oxygen consumption and extraction, GCVF and total coronary vascular resistance. Isoflurane reduced systemic arterial pressure but not PCWP, to presternotomy levels within 6.9 +/- 0.7 minutes at an end-tidal concentration of 1.5 +/- 0.2%. Isoflurane induced a pronounced systemic and coronary vasodilatation and increases in cardiac index, heart rate and regional myocardial oxygen extraction while the GCVF/CSF ratio remained unchanged. While mean regional--MLE% values were not effected by sternotomy, in two patients myocardial lactate production was seen during sternotomy but not during isoflurane. In another two patients, isoflurane induced lactate production.(ABSTRACT TRUNCATED AT 250 WORDS)

Insulin as a vasodilating agent in the first hour after cardiopulmonary bypass.

To study the vasodilating effect of insulin after termination of ECC in aortocoronary bypass surgery, 21 patients were randomized to treatment with 7.5 U of fast-acting insulin/kg b.w. as a bolus injection followed by continuous infusion of 15 U/kg b.w. for 1 hour, or to serve as controls. Insulin administration was begun when the last proximal anastomosis had been completed. Cardiac output and central pressures were monitored for 1 hour after termination of ECC. Systemic vascular resistance in both groups was lower at the end of ECC than before surgery (reduction 39% in the controls, 51% in the insulin-treated group). During the following hour the peripheral resistance increased significantly in the controls (from 20 +/- 2 to 29 +/- 2 mmHg X min X m2/l), but no change was found in the insulin group. It is concluded that insulin can maintain a low vascular resistance after aortocoronary bypass surgery.

Glucose and lactate balances in heart and leg after coronary surgery: influence of insulin infusion.

Glucose and lactate balances in leg (representing mainly skeletal muscle) and heart were studied 1 hour after aortocoronary bypass surgery and insulin treatment. Seventeen men were randomized to receive 25 U fast-acting insulin as a bolus injection, followed by continuous infusion of 1 U/kg b.w. for 1 hour, or to serve as controls. In the leg a small glucose uptake was found while the lactate balance was negative. During the study period the lactate release increased further in the control group. In the myocardium no significant extraction of glucose or lactate could be demonstrated. Insulin treatment resulted in a fivefold increment of leg glucose uptake and in significant myocardial glucose uptake. Myocardial lactate balance was also improved by insulin treatment, with fractional extraction increased from 6 to 21%. It is concluded that myocardial carbohydrate metabolism is restricted in the early period after cardiac surgery, and that this seems to result from insulin resistance induced by the surgical trauma.

The effect of insulin on the leg and splanchnic balance of glucose and gluconeogenic substrates after cardiac surgery.

The effect of insulin and glucose infusion on the leg and splanchnic balance of glucose and the gluconeogenic substrates lactate, pyruvate, alanine and glycerol was studied in 13 patients directly after cardiac surgery. Insulin was infused continuously at a rate of 1.0 Unit/kg/hr during 1 hour. Sixteen patients served as a control group and received no insulin and glucose infusion. A significant increase in arterial lactate concentration in both the control group (from 1.40 +/- 0.19 to 1.68 +/- 0.24 mmol/l p less than 0.01) and the insulin group (from 1.58 +/- 0.27 to 2.07 +/- 0.22 mmol/l, p less than 0.05) was observed. The arterial pyruvate concentration was significantly increased (from 0.075 +/- 0.019 to 0.105 +/- 0.021 mmol/l, p less than 0.01) and glycerol was significantly decreased (from 0.15 +/- 0.03 to 0.12 +/- 0.03 mmol/l, p less than 0.05) during the insulin and glucose infusion. The alanine concentration was unchanged in both groups. Insulin and glucose infusion was followed by an increased leg uptake of glucose (from 0.15 +/- 0.14 to 1.06 +/- 0.16 mmol/min/100 ml, p less than 0.05), and by a changed splanchnic glucose balance (from -8.2 +/- 2.8 to +4.0 +/- 1.2 mmol/kg/min, p less than 0.01). A net leg release and at the same time a net splanchnic uptake of all gluconeogenic substrates was observed. The insulin and glucose infusion did not significantly change either the splanchnic balance or the leg balance of the gluconeogenic substrates.

Splanchnic glucose balance and insulin resistance in the early postoperative phase of cardiac surgery.

The splanchnic balance of glucose was studied in the basal state and at three levels of "clamped" hyperinsulinemia (260 +/- 23, 510 +/- 59, 3875 +/- 367 mU/liter) in 24 patients (43-70 years of age), who had undergone coronary surgery about 1 hr previously. The splanchnic balance of glucose in the basal state was negative in all patients (-1.6 +/- 0.3 mg/kg/min) and was changed into a zero-balance within 30 min when 0.15 or 0.3 U/kg/hr of insulin was infused. At an insulin infusion rate of 1.0 U/kg/hr the net splanchnic glucose balance was turned into a significant positive balance of an average 0.9 +/- 0.3 mg/kg/min.

Association between pulmonary dysfunction and reduced red cell deformability following cardiopulmonary bypass.

Fifty-six patients undergoing open-heart surgery were monitored for red cell trauma during cardiopulmonary bypass (CPB), using a standard red cell microfiltration method. The average red cell deformability was reduced by 38%. Respirator time was shorter in the patients with lesser degrees of red cell trauma, and vice versa. After extubation, the tendency to hypercapnia was greatest in the patients with most red cell trauma during CPB. Hypoxic tendencies in the first 24 postextubation hours were comparably distributed among all levels of red cell trauma.