Off-pump versus on-pump coronary bypass. Comparison of patient characteristics and early outcomes.

AIM: This clinical report details a comparison between the conventional on-pump and beating heart off-pump techniques with particular attention to patient characteristics, perioperative variables and early outcomes. METHODS: We collected prospectively a comprehensive data body from 1131 consecutive patients who underwent isolated CABG in Tampere University Hospital. The morbidity, mortality and length of stay data from the secondary referral hospitals were also collected. One thousand and sixteen (89.8%) patients underwent bypass grafting with cardiopulmonary bypass (CPB, on-pump) and 115 (10.2%) patients without the CPB (off-pump). RESULTS: Thirty-day mortality rates were 4.0% (on-pump) and 2.6% (off-pump, p=0.5). The total postoperative length of stay was 12 (on-pump) and 10 (off-pump) days as the medians (p<0.001). Adverse outcome events among the on-pump and off-pump patients were as follows: postoperative stroke, 2.5% and 0.9% (p=0.3); perioperative myocardial infarction, 7.0% and 7.8% (p=0.7); impaired renal function, 9.5% and 4.3% (p=0.3); re-sternotomy for bleeding or low output, 5.3% and 4.3% (p=0.2); new-onset atrial fibrillation, 38.9% and 24.6% (p=0.002) and the need for red cell transfusions in ICU, 50.3% and 22.6% (p<0.001). Eighty-three percent of the on-pump and 85.2% of the off-pump patients (p=0.5) had a favorable outcome without a major complication. CONCLUSION: Considering the limitations with a nonrandomized study design, we conclude that off-pump CABG is a safe and comparable method of myocardial revascularization in terms of early outcomes. Overall length of stay shorter by 2 days, over a third shorter ventilation time, fewer red cell transfusions and lower frequency of postoperative atrial fibrillation favor off-pump surgery.

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.

Coronary artery dissection, combined aortic valve replacement and coronary bypass grafting in osteogenesis imperfecta.

Osteogenesis imperfecta is an inherited connective tissue disorder. Aortic root dilation, aortic insufficiency and mitral valve prolapse are uncommon cardiovascular manifestations of osteogenesis imperfecta. Cardiac surgery in patients with osteogenesis imperfecta involves a high risk of complication rate. We report a case of coronary artery dissection induced by coronary angiogram in a patient with osteogenesis imperfecta and severe aortic regurgitation. In this case, the dissection of a coronary artery was not completely sealed by coronary stenting, and followed by successful combined aortic valve replacement and coronary artery bypass grafting on an emergency basis.

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.

Allopurinol does not increase free radical scavenging capacity during reperfusion in coronary artery bypass graft patients.

OBJECTIVES: Allopurinol protects the heart against ischaemic events during coronary artery bypass grafting (CABG), possibly because of its antioxidant properties. This double-blind study was designed to investigate whether allopurinol (1 g), given before cardiopulmonary bypass and prior to the opening of cross-clamping, has an antioxidant effect in CABG patients by measuring plasma total peroxyl radical scavenging capacity. DESIGN: Twenty-seven patients with stabile angina were randomized into allopurinol (n = 14) or placebo (n = 13) groups. RESULTS: During 10 min reperfusion, plasma hypoxanthine and xanthine concentrations increased only in the allopurinol group, whereas uric acid concentrations decreased. Total peroxyl radical scavenging capacity (TRAP) decreased from the initial value at all measuring points in both groups. CONCLUSIONS: The reducing effect of allopurinol on free radical generation cannot be seen in TRAP values, obviously because the uric acid concentration of plasma decreases markedly. The positive clinical effects of allopurinol in CABG patients may arise from its direct oxygen free radical scavenging function.

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 allopurinol on myocardial oxygen free radical production in coronary bypass surgery.

OBJECTIVES: Allopurinol protects the heart from reperfusion injury. The aim of this study was to investigate myocardial free radical production during reperfusion with and without allopurinol treatment in coronary artery bypass grafting patients randomized into allopurinol (n = 14) or placebo (n = 13) groups. DESIGN: Allopurinol (1 g) was given blind prior to cardiopulmonary bypass and prior to opening the aorta. Oxygen free radicals were measured before anesthesia in arterial blood, before cross-clamping and 1 and 10 min after reperfusion in arterial and coronary sinus blood. Levels were measured as relative concentrations by the electron spin resonance method. RESULTS: One minute after reperfusion the level of spin-trapped radicals in arterial blood was elevated significantly (p = 0.016) in the allopurinol group, from 7.7 (SE: 0.8) to 8.6 (1.4) and non-significantly (p = 0.074) in the placebo group, from 7.3 (0.7) to 8.3 (0.8). Ten minutes after reperfusion the arterial values were 8.6 (1.5) in the allopurinol and 7.6 (0.7) in the placebo group, the sinus values being 7.6 (1.3) and 8.3 (0.8), respectively. Myocardial free radical production was -0.94 (1.21) in the allopurinol and +0.79 (0.96) in the placebo group after 10 min reperfusion, the difference being significant (p = 0.043). CONCLUSIONS: All patients in both groups had an increasing tendency to free radical production during early reperfusion. Patients treated with allopurinol showed less myocardial production of free radicals, indicating that its protective effect may be due to its antioxidative properties.

Aortic valve stenosis causing a left-to-right shunt in persistent left superior vena cava communicating with the left atrium.

This study demonstrated a rare anomaly of a persistent left superior vena cava draining into the left atrium in a patient with developing left-to-right shunt caused by bicuspid aortic stenosis. The venous system, including the coronary sinus, was otherwise normal. We believe that, in this anatomic situation, a marked increase in left ventricular impedance caused a moderate left-to-right shunt from the left atrium into the left innominate vein. At operation, the aortic valve was replaced with a mechanical prosthesis and the anomalous vein was ligated. The convalescence was uneventful.

Effects of a novel pneumatic vest on postoperative pain and lung function after coronary artery bypass grafting.

A prospective study to evaluate the efficacy of a novel inflatable vest in supporting the sternotomy wound during the early period after coronary artery bypass grafting was carried out in 35 patients. The outcome variables were subjective pain score during cough, and peak expiratory flow (PEF) and vital capacity (VC) on postoperative days 2 and 3. The values without pressure in the vest were used as controls in the individual patients. Use of the vest significantly reduced the cough-associated subjective sternotomy pain score on days 2 and 3, when significant reduction of PEF and VC was also observed. The alleviation of pain by the inflatable vest may improve the efficacy of coughing and bronchial clearance in the immediate postoperative period.

Conduction disturbances after different blood cardioplegia modes in coronary artery bypass grafting. Including comparison with an earlier patient series.

One-hundred and nine patients undergoing coronary artery bypass grafting were randomized to seven groups according to cardioplegia technique (5 types) and right coronary patho-anatomy (2 types). There were no major intergroup differences in postoperative outcome. Conduction disturbances developed in 26 patients, also without intergroup difference. Factors predictive of conduction disturbances were studied by univariate and multivariate analyses. Patients with such disturbances had lower myocardial temperatures than the others and more often postoperative atrial fibrillation (10/26 vs 15/83, p < 0.05). Comparison of this case series with a prospective study from our hospital in 1988-1989 showed that myocardial protection was superior in the present study. The incidence of right bundle branch block was similar in the two studies (24% vs 23%), but that of left-side conduction disturbances (bundle branch or fascicular block) was dramatically reduced (19% vs 1%, p < 0.0001) concomitantly with improved myocardial protection, indicating that development of a left-side conduction disturbance is associated with myocardial injury.

Intestinal ischemia following surgery for aorto-iliac disease. A review of 502 consecutive aortic reconstructions.

A 7-year experience with 502 patients undergoing abdominal aortic reconstruction was reviewed to determine the incidence of intestinal ischemia and the clinical, anatomic and technical factors associated with this complication of aortic surgery. The other complications during the 30-day postoperative period were also collected. A total of 7 (1.4%) patients had intestinal infarction. Of these, colon necrosis occurred in 4, and 3 patients had necrosis in the superior mesenteric artery (SMA) territory. The occurrence of intestinal infarction after operation for ruptured aneurysm was 3.9% (4 patients) and for intact aneurysm 1.3% (3 patients), respectively. None of the 174 patients operated on for aortoiliac occlusive disease developed intestinal infarction. The development of colon necrosis after operation for ruptured aneurysm was mostly in relation to shock and diminished tissue perfusion. Suprarenal aortic clamping with subsequent SMA embolization, prolonged aortic clamping time, and a sporadic thrombosis of the SMA were responsible for small bowel necrosis. In 4 of 7 patients (57%) intestinal infarction led to death. An overall 30-day mortality was 18% (91 patients). Four per cent of these deaths were due to intestinal infarction.

Atrial fibrillation after blood and crystalloid cardioplegia in CABG patients.

In an investigation of factors influencing the occurrence of supraventricular arrhythmias, ninety-eight patients were randomized to receive either cold blood (n = 49) or cold crystalloid (n = 49) cardioplegia during an elective coronary artery bypass grafting operation and were followed for seven days for the development of postoperative atrial fibrillation (AF). Twenty-one patients in the blood-cardioplegia group and nine in the crystalloid-cardioplegia group developed AF (p < 0.01). The patients who developed AF had smaller CK-MB enzyme leaks one hour after the operation (57 +/- 26 iu/L for AF vs 70 +/- 30 iu/L for normal rhythm, p < 0.05), and more often spontaneous beating after cross-clamp release (37% vs 15%, p < 0.05), which indicates that AF was not associated with poor ventricular myocardial protection or conduction system protection. The lesser amount of cardioprotective solution with AF patients (3551 +/- 1585 ml vs 4064 +/- 1562 ml, p < 0.05) and the time of onset of atrial fibrillation (4.0 +/- 1.8 postop. days) indicate that AF is probably caused at least partly by a reperfusion injury at the atrial level. The possibility of atrial fibrillation can be reduced by giving sufficient cardioplegia and giving beta-blocking medicine after the operation.

Atherosclerosis of the visceral arteries.

Thrombosis in the visceral arteries is the most common cause of acute mesenteric ischemia. It typically occurs in areas of atherosclerotic narrowing. Atherosclerosis of splanchnic blood vessels also causes chronic mesenteric ischemia. In the present study, the occurrence of atherosclerosis in the celiac and mesenteric arteries was evaluated in an unselected Finnish autopsy series of 120 patients. Thirty-five patients (29%) had stenosis in the first few centimetres of mesenteric arteries. In 18 cases (15%) at least two mesenteric arteries were stenotic. The celiac artery was the most common site of mesenteric artery stenosis. More distally, only hemodynamically insignificant signs of macroscopic atherosclerosis, fatty streaks or fibrous plaques, observed. The occurrence of mesenteric artery stenosis was strongly associated with aging. Sixty-seven per cent of the subjects aged 80 or more presented with mesenteric artery stenosis, whereas the rate was 6% among those aged less than 40 years. Despite sometimes extensive stenotic alterations in the mesenteric arteries, only one patient in our study had bowel necrosis at autopsy. We conclude that atherosclerosis of mesenteric arteries commonly affects individuals of advanced age. As a part of general arteriosclerotic process of the circulatory system, mesenteric artery atherosclerosis is strongly associated with atherosclerosis in coronary arteries. In addition, there was an association between atherosclerosis in mesenteric arteries and cerebral arteries in the skull base. Thus, a characteristic triad of postprandial abdominal pain, food aversion, and weight loss in an elderly patient with other manifestations of arteriosclerosis should suggest a possibility of the visceral arterial insufficiency.

Rhythm disturbances after blood and crystalloid cardioplegia in coronary artery bypass grafting.

One hundred consecutive patients scheduled for coronary artery bypass grafting were randomized to receive either blood or crystalloid cardioplegia. Successful Holter monitoring for rhythm disturbances was done before and immediately after the operation in 83 cases. With both modes of cardioplegia there were increases in the occurrence of rhythm disturbances postoperatively. The increases were mostly statistically significant. There was no intergroup differences in the occurrence of arrhythmias. The association between these disturbances and cross-clamp times, myocardial temperatures during cross-clamping, myocardial fibrillation times during and after cross-clamping, CK-MB values and perioperative infarction all indicated ischaemia or incomplete myocardial protection as a major cause of the immediate postoperative rhythm disturbances.