Effects of sevoflurane vs. propofol on mitochondrial functional activity after ischemia-reperfusion injury and the influence on clinical parameters in patients undergoing CABG surgery with cardiopulmonary bypass.

The aim of the study was to evaluate the effects of sevoflurane and propofol on the activity of mitochondrial function related to ischemia-reperfusion injury, myocardial damage biomarkers release and clinical parameters in the postoperative period. Seventy-two patients scheduled for elective coronary artery bypass graft surgery with cardiopulmonary bypass were randomized into two groups: 36 patients received sevoflurane during anesthesia (Group S) and 36 patients received propofol (Group P). To investigate the functional activity of mitochondria, we used skinned fibers prepared from biopsies of right atrial tissue before cardioplegia and after the aorta cross-clamp removal (within 10-15 minutes after reperfusion). Patients' clinical data (length of stay in ICU, hemodynamic parameters, duration of mechanical ventilation (MV) and the amount of lactate and troponin I in the blood serum) were evaluated postoperatively. The results showed that, before cardioplegia and after reperfusion, there was no significant difference in the mitochondrial routine and State 3 respiration rates between the groups. The effect of cytochrome c was higher in Group P. Troponin I concentration at the 12(th) hour after the surgery was 2.2 ± 0.8 ng/mL in Group S and 3.5 ± 1.1 ng/mL in Group P (p<0.001). There were no significant differences in the duration of mechanical ventilation, hemodynamic parameters and length of stay in the ICU between the groups. We conclude that sevoflurane slightly protects the mitochondrial outer membrane from ischemia-reperfusion injury and the loss of cytochrome c, yet has the similar effect on clinical parameters in the postoperative period when compared to propofol.

Effects of intraoperative external head cooling on short-term cognitive function in patients after coronary artery bypass graft surgery.

The aim of study was to assess the effects of an intraoperative external head-cooling technique on cognitive dysfunction in the early postoperative period (at the 10th day) in patients after coronary artery bypass graft (CABG) surgery. Patients in Group H (n=25) were cooled with CPB and the intraoperative, external head-cooling technique, patients in Group C (n=25) were cooled only with cardiopulmonary bypass (CPB) to achieve mild hypothermia (33 - 34 °C). Cognitive function was analyzed before the operation and after the surgery using the Mini Mental State Examination (MMSE), the Modified Visual Reproduction Test from the Wechsler Memory Scale, Trail Making (A/B), WAIS--Digit Span (WDS) and WAIS Digit Symbol Substitution Test (WDSST). The incidence of cognitive impairment at the 10th day after the surgery was 36% (n=9) in Group H and 64% (n=16) in Group C (p=0.048). The temperature during the aortic cross-clamp period was associated with a lower rate of cognitive dysfunction (p=0.05, r(2)=0.09). The intraoperative, external head-cooling technique during the aortic cross-clamp period has a neuroprotective effect and leads to less short-term cognitive function impairment after CABG surgery.

The influence of mean arterial blood pressure during cardiopulmonary bypass on postoperative renal dysfunction in elderly patients.

The aim of the study was to find out if there is an optimal mean arterial blood pressure (MABP) during cardiopulmonary bypass (CPB) for renal function in elderly patients during the early postoperative period. We analysed the data of 122 patients >70 years of age with normal preoperative renal function who had been subjected to coronary artery bypass grafting (CABG) procedures on CPB. Patients were divided into 3 groups, according to MABP during CPB: group MP (n=50) included patients whose MABP was maintained between 60-70 mmHg; group LP (n=36), the MABP was <60 mmHg; and group HP (n=36) where the MABP was >70 mmHg. The patients' clinical data were evaluated during the first three postoperative days. The rate of renal impairment (urine output <50ml/h) in the early postoperative period after cardiac surgery did not differ among the groups. Oliguria developed in 3 patients (6%) of the MP group, in 2 patients (5.6%) in the LP group and in 6 patients (16.7%) in the HP group (χ(2)=3.6, df=2, p=0.161). Evaluation of MABP on renal excretion showed that there was no difference in urine output among the groups. Serum creatinine levels at the end of the first postoperative day in groups MP, LP and HP were 102.7±20.1, 116.4±58.6 and 113.2±39.8 µmol/L, respectively (F=0.5, df=2, p=0.640). There were no significant differences among the groups at the end of the second and the third day either. Volume balance at the end of surgery and during the early postoperative period was similar in all groups. The need for diuretics did not differ among the groups. The length of postoperative hospital stay was not significantly different among the groups. Our study did not reveal any relationship between a MABP of 48-80 and postoperative renal dysfunction in elderly patients after CABG surgery.

Cardiopulmonary bypass management and acute renal failure: risk factors and prognosis.

The aim of the study was to investigate if acute renal failure (ARF) following cardiac surgery is influenced by CPB perfusion pressure and to determine risk factors of ARF. Our research consisted of two studies. In the first study, 179 adult patients with normal preoperative renal function who had been subjected to cardiac surgery on CPB were randomized into three groups. The mean perfusion pressure (PP) during CPB in Group 65 (68 patients) was 60-69.9 mmHg, in Group 55 (59 patients) -- lower than 60 mmHg and in Group 75 (52 patients) -- 70 mmHg and higher. We have analyzed postoperative variables: central venous pressure, the need for diuretics, urine output, fluid balance, acidosis, potassium level in blood serum, the need for hemotransfusions, nephrological, cardiovascular and respiratory complications, duration of artificial lung ventilation, duration of stay in ICU and in hospital, and mortality. In the second study, to identify the risk factors for the development of ARF following CPB, we retrospectively analysed data of all 179 patients, divided into two groups: patients who developed ARF after surgery (group with ARF, n = 19) and patients without ARF (group without ARF, n = 160). We found that urine output during surgery was statistically significantly lower in Group 55 than in Groups 65 and 75. The incidence of ARF in the early postoperative period did not differ among the groups: it developed in 6% of all patients in Group 65, 4% in Group 55 and 6% in Group 75. There were no differences in the rate of other complications (cardiovascular, respiratory, neurological disorders, bleeding, etc) among the groups. There were 19 cases of ARF (10.6%), but none of these patients needed dialysis. We found that age (70.0 +/- 7.51 vs. 63.5 +/- 10.54 [standard deviation, SD], P = 0.016), valve replacement and/or reconstruction surgery (57.9% vs. 27.2%, P = 0,011), combined valve and CABG surgery (15.8% vs. 1.4%, P = 0.004), duration of CPB (134.74 +/- 62.02 vs. 100.59 +/- 43.99 min., P = 0.003) and duration of aortic cross-clamp (75.11 +/- 35.78 vs. 53.45 +/- 24.19 min., P = 0.001) were the most important independent risk factors for ARF. Cardiopulmonary bypass perfusion pressure did not cause postoperative renal failure. The age of patient, valve surgery procedures, duration of cardiopulmonary bypass and duration of aorta cross-clamp are potential causative factors for acute renal failure after cardiac surgery.

[The influence of cardiopulmonary bypass on respiratory function in an early postoperative period].

AIM: To investigate the influence of cardiopulmonary bypass (CPB) on pulmonary function early after the operation by evaluating Qs/Qt. MATERIAL AND METHODS: Twenty one patients after elective myocardial revascularization surgery have been analysed. Group 1 included 11 patients who have undergone cardiac surgery with CPB. Group 2 included 10 patients who have undergone cardiac surgery without CPB. Blood gas analysis for intrapulmonary shunt calculations was made 20 minutes after the induction of anesthesia and 4 hours after surgery. Qs/Qt was also calculated. RESULTS: Four hours after surgery Qs/Qt increased compared to preoperative data in group 1 (from 8.6 +/- 2.1 to 16.8 +/- 2.6%, p < 0.02). Intrapulmonary shunt was greater in group 1 vs group 2 four hours after the surgery (16.8 +/- 2.6 and 7.8 +/- 2.1%, p < 0.02). In group 1, alterations in a pulmonary function (81.8%) were caused by atelectasis detected by chest x-ray. In group 2 neither increase in intrapulmonary shunt nor atelectasis were determined. CONCLUSION: Arterial hypoxemia and an increase in the intrapulmonary shunt (due to atelectasis) have proven that alterations in the pulmonary function occur more often and are more pronounced in patients after surgery with cardiopulmonary bypass.

[Ischemic cardiomyopathy: remote complications and their prognostication after isolated myocardial revascularization].

Aim of investigation was to study rate of remote cardiovascular complications after aorto-coronary grafting (ACG) in patients with ischemic cardiomyopathy and revelation of informative pre- and early postoperative markers of left ventricular (LV) function for determination of prognosis of cardiovascular complications and functional state of patients in remote postoperative period. Doppler echocardiographical parameters of left ventricular function were assessed in pre- and early postoperative period in 107 patients in whom cardiovascular events did not recur in late postoperative period (during 1 year) and in 63 patients who had recurrent cardiovascular events. Influence of a sign (x) on probability p(x) of cardiovascular events in postoperative period was estimated on the basis of logistic model. Rate of cardiovascular complications during 1 year after ACG in patients with ischemic cardiomyopathy was 40%. Most significant prognostic markers of cardiovascular complications in remote postoperative period were LV ejection fraction and deceleration time of early filling before surgery and in early postoperative period, as well as LV end systolic diameter in early postoperative period (p<0.05).

Electrostimulated cardiomyoplasty: from experimental to clinical studies.

Cardiomyoplasty is a method for managing patients with dilated cardiomyopathy. We evaluated the means of carbon fiber electrode stimulation of the nerve to the latissimus dorsi muscle (LDM) in dogs to increase skeletal muscle contractility. Histochemical examination of biopsies of muscle electrically conditioned by a single pulse stimulator via the thoracodorsal nerve demonstrated transformation of muscle into fatigue resistant slow fibers without damage to muscle or nerve tissue. Canine experiments confirmed that carbon fibers are one of the best electrodes for chronic LDM stimulation. Between 1988 and 1992, we operated on ten patients, New York Heart Association (NYHA) Class III (4 patients) and Class IV (6 patients), with a mean left ventricular ejection fraction (LVEF) of 23%. The indications for cardiomyoplasty were idiopathic (7 patients) and ischemic (3 patients) cardiomyopathy refractory to maximum medical therapy. The operative procedure was performed via median sternotomy (5 patients) and left thoracotomy (5 patients). There was one operative mortality and two additional deaths during the late follow-up period. The mean postoperative LVEF increased to 27%. Functional class, quality-of-life, and ventricular performance were improved after cardiomyoplasty. Two of the surviving patients are in NYHA Class I, four in Class II, and one in Class III.