Ischemic preconditioning protects right ventricular function in coronary artery bypass grafting patients experiencing angina within 48-72 hours.

BACKGROUND: To test whether ischemic preconditioning (IP) is able to protect the myocardium in recently unstable CABG patients. EXPERIMENTAL DESIGN: prospective, randomised, controlled clinical study. SETTING: University Hospital. PATIENTS: Forty CABG patients with recent unstable angina were randomised into an IP group (n=20) and a control group (n=20). Subgroup was divided based on the time of the most recent ischemia onset before the operation. INTERVENTION: The IP group was preconditioned with 2 cycles of 2-min ischemia followed by 3-min reperfusion before cross clamping. MEASURES: Hemodynamic data were monitored till the 1st POD. Biochemical markers were measured till the 2nd POD. RESULTS: There were no differences in cardiac index (Cl) and right ventricular ejection fraction (RVEF) in patients experiencing angina within 48 hours prior to operation. The percentage changes in CI and RVEF at 1 hour after declamping were significantly better in the IP group in patients experienced angina within 48-72 hours (106% vs 88% of baseline, p=0.027 and 103% vs 81% of baseline, p=0.023). No difference in postoperative cardiac troponin I (CTnI) and CK-MB was found between the IP and controls in either subgroup. CONCLUSIONS: IP has a beneficial effect on global and right ventricular hemodynamic functional recovery in unstable CABG patients experiencing angina within 48-72 hours prior to the operation. However, IP has no additional protective effects in unstable CABG patients who experience angina within 48 hours.

The protective effects of preconditioning decline in aged patients undergoing coronary artery bypass grafting.

OBJECTIVE: We sought to investigate the effects of myocardial ischemic preconditioning in adult and aged patients undergoing coronary artery bypass grafting. METHODS: Eighty patients with 3-vessel disease undergoing coronary artery bypass grafting were randomized into one of the following groups: adult ischemic preconditioning, adult control, aged ischemic preconditioning, and aged control. Hemodynamic data and cardiac troponin I values were compared between the groups. The ischemic preconditioning groups received 2 periods of 2 minutes of ischemia, followed by 3 minutes of reperfusion. The Student t test, chi(2) test, and analysis of variance for repeated measures were used for the statistical analysis. RESULTS: The baseline for right ventricular ejection fraction and cardiac index was similar. Right ventricular ejection fraction was depressed after the operation in all groups. Ischemic preconditioning significantly improved the recovery of right ventricular ejection fraction and cardiac index after the operation in adult patients (P =.013 and.001, respectively), but in the aged group there was no difference in the changes of ejection fraction and cardiac index (P =.232 and.889, respectively). The cardiac troponin I value in the adult patients subjected to ischemic preconditioning was lower than that in the adult control subjects (P =.046), but in aged patients undergoing ischemic preconditioning, the value was similar to that in aged control subjects (P =.897). Ischemic preconditioning also resulted in a shorter postoperative mechanical ventilation time and in less inotropic use in the adult group. CONCLUSION: Ischemic preconditioning protects the heart from ischemic reperfusion injury in adult patients undergoing coronary artery bypass grafting. The beneficial effects of ischemic preconditioning are manifested as a better recovery of right ventricular and global hemodynamic function, cellular viability, and surgical outcome. The protective effect of ischemic preconditioning is diminished in aged patients undergoing coronary bypass.

Myocardial lactate production is not involved in the ischemic preconditioning mechanism in coronary artery bypass graft surgery patients.

OBJECTIVE: To study the relationship between ischemic preconditioning (IP) and lactate production and their impact on coronary artery bypass graft surgery patients. DESIGN: Prospective, randomized, controlled study. SETTING: University hospital. PARTICIPANTS: Eighty 3-vessel disease coronary artery bypass graft surgery patients with stable and unstable angina pectoris. INTERVENTIONS: The IP patients were preconditioned with 2 periods of 2-minute ischemia followed by 3-minute reperfusion before aortic cross-clamping. MEASUREMENTS AND MAIN RESULTS: The cardiac index (CI) after surgery was significantly higher in the IP group than in controls among stable patients (p = 0.013). IP was not effective in CI recovery in unstable patients. The baseline values of lactate production were 11.6%, 20.3%, -7.0%, and -2.9% in stable IP, stable control, unstable IP, and unstable control patients. Compared with baseline, lactate production increased significantly after the IP protocol (39.0% and 47.5% in the stable and unstable patients), and operation (47.5%, 31.7%, 35.4%, and 35.6% in stable IP, stable control, unstable IP, and unstable control patients) but not after 10 minutes of cardiopulmonary bypass (29.7% and 19.0% in the stable and unstable patients). There were no differences among the groups in lactate production after the operation. Lactate production after the IP protocol was negatively associated with CI recovery after surgery in the IP patients (p = 0.026). CONCLUSION: The IP effects do not include modulation of lactate production. IP induces lactate production, but it seems not to be involved in the triggering process.

Effect of ischaemic preconditioning, cardiopulmonary bypass and myocardial ischaemic/reperfusion on free radical generation in CABG patients.

OBJECTIVE: To investigate the free radicals (FR) generation after ischaemic preconditioning and cardiopulmonary bypass and during reperfusion in CABG patients, and the role of ischaemic preconditioning. METHODS: Forty-three CABG patients were randomised into an ischaemic preconditioning and a control group. The protocol for ischaemic preconditioning was two cycles of 2-min ischaemia followed by 3-min reperfusion. Free radicals were measured using electron spin resonance spectroscopy. Global and right heart functions were collected. RESULTS: The free radicals generation in coronary sinus blood in the ischaemic preconditioning group was 9.7 and 16.6% after the ischaemic preconditioning protocol and 10 min after declamping, 6.8 and 13.3% in the controls. The free radicals in arterial samples were, respectively, 21, 14, 10 and 9% at 10 min, 1, 2 and 24 h after reperfusion. Cardiac index (CI) and right ventricular ejection fraction (RVEF) were improved by ischaemic preconditioning. CONCLUSION: Both ischaemic preconditioning and cardiopulmonary bypass induced free radicals generation. Although ischaemic preconditioning had no effect on free radicals generation after the operation, it protected against postoperative stunning.

Effect of ischemic preconditioning on myocardial protection in coronary artery bypass graft patients : can the free radicals act as a trigger for ischemic preconditioning?

OBJECTIVE: To investigate the interrelationship of free radicals (FRs), ischemic preconditioning (IP), and hemodynamic function in coronary artery bypass graft (CABG) patients. DESIGN: Prospective, randomized, and controlled clinical study. PATIENTS: Forty CABG patients were randomized into an IP group (n = 20) and a control group (n = 20). INTERVENTION: The IP group was preconditioned with two cycles of two-min ischemia followed by 3-min reperfusion before cross-clamping. MEASUREMENT AND RESULTS: FR content in coronary sinus blood was measured directly using alpha-phenyl-N-tert-butylnitrone-electron spin-trapped spectroscopy. A small amount of FRs was generated after the IP protocol (5.6% above the baseline) but not in control subjects. A larger amount was generated 10 min after declamping in both groups (8.4% in IP protocol and 7.7% in control subjects). Hemodynamic function recovered better in the IP group at 1 h and 6 h after declamping. There was a significant negative correlation between FR generation after declamping and left ventricular stroke work index (LVSWI) at 1 h and 6 h after declamping (r = -0.71 and - 0.59, respectively) in the control subjects but not in the IP group. There was a significant positive correlation between FR generation after the IP protocol and cardiac index at 1 h and 6 h (r = 0.50 and 0.61, respectively) and LVSWI at 1 h and 6 h (r = 0.56 and 0.54, respectively) after declamping in the IP group but not in the control subjects. CONCLUSION: FR generation after the operation correlates with ventricular functional depression in CABG patients. IP protects the stunning heart but does not alter FR generation. The association of better hemodynamic recovery after CABG with FR generation during the IP period suggests that FRs might act as one of the triggers for IP.

Beneficial effects of ischemic preconditioning on right ventricular function after coronary artery bypass grafting.

BACKGROUND: Preservation of right ventricular myocardium is unsatisfactory in patients with critical stenosis or occlusion of the right coronary artery. The aim of this study was to investigate whether ischemic preconditioning (IP) improved the recovery of right ventricular function after coronary artery bypass grafting. METHODS: Forty patients with three-vessel disease who had coronary artery bypass grafting were randomly assigned to the IP group (n = 20) or control group (n = 20). In the IP group, two cycles of two minutes of ischemia after three minutes of reperfusion were given before cross-clamping. Hemodynamic data were collected. Right ventricular ejection fraction was measured by thermodilution. RESULTS: Right ventricular ejection fraction and right ventricular systolic volume index were decreased post-operatively (lowest value at 6 hours postoperatively). The changes in right ventricular ejection fraction were significantly milder in the IP group postoperatively (p = 0.012). The decrease in right ventricular systolic volume index postoperatively was also less in IP patients (p = 0.002). Fewer inotropic drugs were used in the IP group compared with controls. CONCLUSIONS: Ischemic preconditioning had a myocardial protective effect on recovery of right ventricular contractility in patients who had coronary artery bypass grafting.

Superiority of mitral valve replacement with preservation of subvalvular structure to conventional replacement in severe rheumatic mitral valve disease: a modified technique and results of one-year follow up.

BACKGROUND AND AIM OF THE STUDY: Mitral valve replacement with preservation of the subvalvular apparatus (MRVP) has been proven superior to conventional mitral valve replacement (MVR). We devised a simple modified MVRP method in this prospective, randomized study to investigate the clinical effects and one-year follow up echocardiographic results of MVRP compared with MVR in patients with severe rheumatic mitral insufficiency (MI). METHODS: Sixty-eight patients with severe rheumatic MI with or without stenosis were randomized to MVRP (n = 35) and MVR (n = 33) groups. In MVRP patients, the preserved tissue was pulled back posteriorly to the posterior wall of the left ventricle, then plicated and reaffixed to one-fourth of the annular circumference in the posterior annulus, in order to prevent left ventricular outflow tract (LVOT) obstruction. Clinical data including cumulative ventricular arrhythmias and use of inotropes were collected. Echocardiography examination was performed before surgery, and at five days, three months and one year thereafter. RESULTS: There were no preoperative differences patient data. The cross-clamp time was 2.2 min longer in MVRP patients. The one-month mortality rate after surgery was lower in MVRP patients (2.9% versus 15.2%, p = 0.074). Mechanical ventilation and ICU times were shorter in the MVRP group (17.6 versus 24.8 and 52.5 versus 70.6 h, p = 0.001 and 0.1, respectively). There were fewer ventricular arrhythmias and less need for inotropic support in this group. One year follow up echocardiography data showed better preserved left ventricular ejection fraction (LVEF) and better recovery of heart size after MRVP. There was no indication that preserved valvular tissue interfered with mechanical valve function, or caused LVOT obstruction. CONCLUSION: This modified MVRP technique is simple, effective and without risk of LVOT obstruction. In severe rheumatic MI patients the outcome of MVRP is superior to that of conventional MVR in term's of mortality, postoperative care needs, left ventricular function and heart dimensions.

Ischaemic preconditioning has a beneficial effect on left ventricular haemodynamic function after a coronary artery biopass grafting operation.

OBJECTIVE: Ischaemic preconditioning (IP) is the most effective procedure for endogenous myocardial protection. However, studies on the effects of IP in cardiac surgery are rare and controversial. The present aim was to investigate whether IP improves the haemodynamic recovery of CABG patients. DESIGN: The study included 40 stable CABG patients with 3-vessel disease, randomized into an IP group (n = 20) and a control group (n = 20). In the IP group two cycles of 2-min ischaemia following 3-min reperfusion before cross-clamping were induced. The haemodynamics of the patients were followed-up to the first postoperative morning. RESULTS: The cardiac index decreased at 1 and 6 h after surgery in the control group but increased in the IP group (-0.33 vs 0.09 l/min/m2, p = 0.02 and -0.15 vs 0.57 l/min/m2, p = 0.001, respectively). Depressions in the left ventricular stroke work index and the right ventricular stroke work index at 6 h after surgery were more severe in controls and were statistically significant (p = 0.049 and 0.007, respectively). Less inotropic support was used in the IP group. There were no differences in serum CK-MB, cardiac troponin I, myoglobin or lactate values between the two groups. CONCLUSION: IP has a beneficial effect on left ventricular haemodynamic recovery after a CABG operation.

Protective effect of unstable angina in coronary artery bypass surgery.

OBJECTIVE: To test the hypothesis that recent ischaemic episodes in unstable cases have a protective effect on coronary artery bypass graft (CABG) patients. MATERIALS AND METHODS: Twenty unstable patients with ischaemic episodes within 3 days before operation were compared with 20 stable patients. Haemodynamic data were monitored up to the first postoperative day. Biochemical markers were measured up to the second postoperative day. RESULTS: The cardiac index decreased at 1 and 6 h after declamping in the stable group (89% and 97% of baseline) but increased in unstable patients (104% and 122%, p =0.038 and 0.036, respectively). The depression in the right ventricular stroke work index was significantly attenuated in the unstable group (58%, 67% and 83% in stable and 90%, 97% and 117% in unstable patients, p = 0.027, 0.010 and 0.049 at 1 and 6 h after declamping and 1st POD). The release of cardiac troponin I (CTnI) and CK-MB was significantly lower in the unstable group at 6 h after declamping (5.6 +/- 2.9 and 19.0 +/- 6.3 microg/l in unstable vs 17.4 +/- 9.6 and 25.8 +/- 12.3 microg/l in stable patients, p = 0.000 and 0.039, respectively). CONCLUSION: Recent unstable angina before CABG might act as an ischaemic preconditioning stimulus and could improve haemodynamic function and cellular viability. Delayed preconditioning most likely causes this protective effect.

[Effect of anti-aging drug on DNA methylase of brain in rats].

DNA methylase activity of brain in Wistar rats treated with Shenfang Bushen Shengxue Drug (SBSD) was observed using 3H-labelled methyl group of S-adenosyl-methionine incorporated into DNA. It was found that the SBSD has a marked effect on anti-aging. After SBSD treatment the specific activity of DNA methylase increased, the thermostability and salt-tolerance of it improved slightly, its optional pH changed from 7.5 to 8.0. A and a difference was found between the electrophoresgram of partially purified product of DNA methylase in SBSD treated rats and that in normal rats, suggesting SBSD could change the activity and characteristics of DNA methylase so as to affect the level of DNA methylation, which might be one pathway of SBSD effects on anti-aging.

[Effect of anti-aging drug on the activity of DNA methylase in rat liver].

An obvious anti-aging effect was found by Bushen Shengxue drug to treat Wistar rats. Using a method about incorporation of 3H-labeled methyl group of S-adenosyl-methionine (SAM) into DNA bases, the DNA methylase activity was assayed. The specific activity of DNA methylase was increased by treatment of this drug. The chromatographic behaviour of DNA methylase from rat liver was also changed. These results showed that the mechanism of anti-aging effect of this drug is probably related to DNA methylation.

Posterior vertebral instrumentation for correction of scoliosis.

One hundred and five patients were treated by instrumentation for various spinal conditions by means of the posterior route. There were 90 patients with scoliosis in this series. Of these, 61 cases (67.7%) were corrected by Harrington distraction rod and segmental wire fixation. The various degrees of deformity in these patients produced the correction figures of 36.4%-42.6% of the original. The complications were eight cases of displacement of the upper hook, two cases of superficial infection, and one case of late infection. There were no cases of neurologic injury. The discussion centers on the importance of the awake test, the estimation of expected correction before surgery, the Harrington distraction rod with segmental wire fixation as an effective method, and the measures to be taken for the prevention of displaced fractures at the site of the upper hook in kyphoscoliosis correction.