Coronary atherosclerosis distribution and the effect of blood glucose level on operative mortality/morbidity in diabetic patients undergoing coronary artery bypass grafting surgery: a single center experience.

OBJECTIVE: The study aim was to investigate the effect of blood glucose level on atherosclerotic lesion distribution and the contribution to the operative mortality/morbidity in diabetic patients who underwent coronary artery bypass grafting (CABG). METHODS: Between 1986-2003, a total of 2095 patients with diabetes mellitus underwent CABG. The analysis was carried out retrospectively from the clinical records. The patients were divided into four groups according to the blood glucose levels that were obtained when they first applied to hospital; Group 1 (492 patients with blood glucose < 120 mg/dl), group 2 (1112 patients with blood glucose - 120-200 mg/dl, group 3 (261 patients with blood glucose 201-250 mg/dl) and group 4 (230 patients with blood glucose > 250 mg/dl). One way ANOVA test was used for the statistical analysis of continuous variables and Chi-square test was used for analyzing the categorical variables. RESULTS: Emergent operation rate due to acute ischemia gradually increased from Group 1 to Group 4 and reached 6.6% in Group 4 (p=0.005). Operation time and the duration of cardiopulmonary bypass and cross clamp were significantly longer in patients with high blood glucose levels (p<0.05). Necessity for inotropic drug administration postoperatively (p<0.05) and mechanical support (p<0.05) were significantly higher also. The hospital mortality in group 3 was 9.6% and in group 4 was 11.3% (p=0.09). No statistically significant difference was found in terms of morbidity between the groups (p>0.05). The multi-vessel coronary artery disease was more common in groups with high blood glucose level (p<0.05). As the blood glucose level raised, patients were more frequently (p<0.05) confronted with distal left anterior descending artery, middle circumflex artery and right coronary artery lesions. CONCLUSION: Uncontrolled blood glucose level not only increased the perioperative complications but also the incidence of middle and distal coronary artery lesions. It is necessary to diagnose and aggressively treat the high blood glucose level especially before the CABG.

Cardiac valve replacement with mechanical prostheses in patients aged 65 years and over.

BACKGROUND AND AIM OF THE STUDY: Recent data regarding the performance of mechanical prostheses in patients aged > or =65 years are scant. Hence, the outcome of mechanical prosthesis implantation in this age group has been retrospectively evaluated. METHODS: Between January 1990 and October 2002, 253 patients (163 males, 90 females) aged > or =65 years (mean age 68.2 years) underwent aortic valve replacement (AVR) and/or mitral valve replacement (MVR) at the authors' institution. RESULTS: Among the patients, 94 (37.2%) had MVR, 137 (54.1%) had AVR, and 22 (8.7%) had MVR+AVR. In total, 99 patients (39.1%) had concomitant coronary artery bypass grafting (CABG). The early mortality rate was 11.1%; that for patients aged > or =70 years was greater than that for patients aged 65-69 years (14.5% versus 9.6%, p <0.001). The overall actuarial survival was 91.3 +/- 2.4% at 5 years, 81.1 +/- 4.1% at 8 years, and 73.8 +/- 6.3% at 10 years. Actuarial survival for patients with isolated AVR and MVR at 10 years was 84.7 +/- 6.0% and 61.4 +/- 18.8%, respectively. Actuarial survival at 10 years for patients with isolated valve replacement was 76.1 +/- 8.1%, and 68.7 +/- 10.2% for patients with concomitant CABG (p = 0.680). Actuarial survival at 10 years was 81.3 +/- 6.9% for patients aged 65-69 years, and 50.3 +/- 11.0% for patients aged > or =70 years (p = 0.001). Freedom from a major thromboembolic event was 99.4 +/- 0.7% at five years and 86.3 +/- 6.0% at 10 years, while freedom from hemorrhage was 90.4 +/- 2.6% and 70.3 +/- 6.8%, respectively. CONCLUSION: Mechanical prostheses can be used in patients aged > or =65 years, with favorable results. However, on the basis of the present findings, patients aged > or =70 years have a reduced early and late survival.

[Reexploration for bleeding and tamponade in intensive care unit following open heart surgery]. / Açik kalp ameliyatlari sonrasi kanama veya tamponad nedeniyle yogun bakimda yapilan reeksplorasyonlar.

OBJECTIVE: Following open-heart surgery some patients can need reexploration in the intensive care unit due to bleeding or pericardial tamponade. This study evaluates the impact of reexploration in the intensive care unit (ICU) on morbidity and mortality rates. METHODS: Between January 1990 and January 2002 overall 18,578 open heart surgery procedures were performed in our clinic and among them 570 (3%) patients required reexploration due to bleeding or pericardial tamponade. Reexplorations were done in the operating room (OR) in 385 (67.5%) patients and in the ICU in 185 (32.5%) patients. RESULTS: Among patients 383(67.2%) were male and 187(32.8%) were female. Mean age for reexploration in the OR group was 46.9+/-16.3 years, and in the ICU group was 48.2+/-15.7 years. The use of fresh frozen plasma and bank blood was significantly higher in the ICU group (p<0.0001). Fifty patients (27%) who were reexplored in ICU had intraaortic balloon pump (IABP) support (p<0.0001). Sixty-six patients (17.1%) died in OR group and 70 patients (37.8%) died in the ICU group (p<0.001). Following reexploration, 24 (6.2%) patients in the OR group and 17 (9.1%) patients in the ICU group had major infection (p>0.05). There was no statistically significant difference among groups in hospital stay time. CONCLUSION: Following open-heart surgery, especially among hemodynamically unstable patients, to avoid possible problems of transfer to the OR and time lost, explorations can be done in ICU. This practice does not increase morbidity and hospital stay.

Transventricular mitral valve repair in patients with acute forms of ischemic mitral regurgitation.

Transventricular mitral valve surgery combined with left ventricular restoration avoids atriotomy and provides a larger operative field. We describe a series of 5 patients in whom we performed transventricular mitral valve repair by various techniques, such as band annuloplasty, papillary muscle reattachment, chordal cutting, and edge-to-edge repair. The more acute forms of ischemic mitral regurgitation, as found in our patients, can coexist with post-myocardial infarction contained rupture or post-myocardial infarction ventricular septal rupture. Because these patients already have an indication for ventriculotomy, concomitant transventricular repair of the mitral valve can render a separate atriotomy unnecessary and thereby shorten the duration of cardiopulmonary bypass. Moreover, in patients with acute presentations, the absence of atrial dilation (this last associated with chronic cases) might make transventricular repair a better choice than the more difficult atrial approach.

How DMSO, a widely used solvent, affects spinal cord injury.

The aim of this experimental study was to investigate whether dimethylsulfoxide (DMSO) has protective effects on spinal cord ischemia-reperfusion (I/R) injury. New Zealand rabbits were enrolled in the study. In addition to the control group, the study group received 0.1 mL/kg DMSO prior to ischemia. Blood samples were taken to obtain nitrite-nitrate levels during the surgical procedure. After neurological evaluation at 24 hr of reperfusion, lumbar spinal cords were removed for electron microscopic evaluation and malondialdehyde and myeloperoxidase measurements. The mean Tarlov score of the DMSO group was higher than that of the control group. Electron microscopic examination was carried out with tissue samples at 24 hr of reperfusion. The DMSO group had better preservation with the electron microscopic scoring compared to the control group. Malondialdehyde and myeloperoxidase levels were decreased in the DMSO group compared to the control group. Nitrite-nitrate levels were also lower in the DMSO group compared to control at 5 and 30 min of reperfusion. This study demonstrates a considerable neuroprotective effect of DMSO on neurological, biochemical, and histopathological analyses during periods of spinal cord I/R injury in rabbits. Although there was a difference between the DMSO and control groups in all measured parameters in our study, this was not statistically significant. DMSO deserves further investigation related with spinal cord ischemia and reperfusion. We should also consider the effect of DMSO when we use it as a solvent or vehicle during experimental I/R models.

In which period of injury is resveratrol treatment effective: ischemia or reperfusion?

The periods of ischemia and reperfusion represent different characteristics by lack of oxygen and reoxygenation. The aim of this experimental spinal cord injury model was to investigate whether resveratrol has protective effects during ischemia or reperfusion and the mechanism of the protection by using N-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthase. Rabbits were divided into seven groups according to the time of administration of resveratrol or L-NAME (RI and RR, resveratrol during ischemia or reperfusion; IL and RL, L-NAME during ischemia or reperfusion; RILR, resveratrol during ischemia and L-NAME during reperfusion; LIRR, L-NAME during ischemia and resveratrol during reperfusion; control group). After neurologic evaluation at the twenty-fourth hour of reperfusion, lumbar spinal cords were removed for electron microscopic evaluation, immunohistochemical staining for apoptosis, and malondialdehyde (MDA) and myeloperoxidase (MPO) measurements. The RILR group had the best functional recovery, with a mean 3.6 Tarlov score (P < 0.05), and showed near normal electron microscopic findings (scores of 7.6 +/- 0.9 for the control group and 3.9 +/- 2.9 for the RILR group, P < 0.05). MPO and MDA levels were decreased in all groups compared with the control group, but only the decrement in the RILR group reached statistical significance. Immunohistochemical analysis showed that the groups including resveratrol and L-NAME together had the best staining for apoptosis. Resveratrol exhibits important protection by means of neurologic outcome, histopathologic analysis, and biochemical analysis, especially when used in during ischemia followed by L-NAME administration during reperfusion. Also, resveratrol protects against apoptosis, especially when combined with L-NAME.

Evaluation of hemodynamic changes in patients with mitral valve replacement using dobutamine stress echocardiography.

OBJECTIVE: The aim of this study was to investigate the response of heart to stress according to the size of the prosthetic valve in patients who had undergone mitral valve replacement by using dobutamine stress echocardiography (DSE) and to evaluate the relationship between the size of the prosthetic valve and cardiac recovery-remodeling process. METHODS: Thirty-nine patients, who had undergone mitral valve replacement were compared in terms of left ventricular diameters, systolic functions and cardiac mass indexes in order to investigate the effect of the mechanical valve size on postoperative cardiac remodeling in this longitudinal study. They were divided into three groups according to their valve size: Group 1 (valve size<29 mm, n=11), Group 2 (valve size=29 mm, n=11) and Group 3 (valve size>29 mm, n=17). Statistical analysis was performed using Chi-square and one-way ANOVA tests to determine the statistical differences between the groups. The repeated measurements of two-way ANOVA test was used to analyze effects during long-term follow-up. RESULTS: Only Group 1 patients achieved a significant decrease in terms of left ventricular mass index and end-diastolic diameter (138.3+/-29.7 g/m2 vs 86.6+/-15.6 g/m2 and 5.1+/-0.5 cm vs. 4.4+/-0.4 cm, p<0.05). Group 3 patients' left ventricular ejection fraction become worse after the operation (64.0+/-5.6% vs. 55.9+/-6.5%, p<0.05). Maximum and mean pressure gradients across the mitral prosthesis as well as pulmonary artery pressure were significantly increased in all groups during DSE. Maximum gradients increased from 14.2+/-4.6 to 20.7+/-7.5 mmHg in Group 1 (p<0.05), 11.6+/-4.7 to 16.2+/-6.8 mmHg in Group 2 (p<0.05), and 10.6+/-3.1 to 20.8+/-12.7 mmHg in Group 3 (p<0.05). Isovolumic relaxation time decreased in all groups following the dobutamine infusion, as expected, but this decline was not significant in Group 3. CONCLUSION: A worsening in left ventricular systolic function was observed in large- sized valve prosthesis group. Only the patients who had undergone MVR with small-sized valve prosthesis achieved a decrease in cardiac mass index and preservation of the systolic function. The echocardiographically determined differences and mass index that appeared after the operation may point out that, the effect of the operation on cardiac remodeling can be related with the ventricular size.

Effect of low-dose amiodarone and magnesium combination on atrial fibrillation after coronary artery surgery.

BACKGROUND: To evaluate whether postoperative administration of intravenous low-dose amiodarone and magnesium sulfate (MgSO(4)) combination would reduce the incidence of atrial fibrillation following coronary artery bypass grafting (CABG) in normomagnesemic high-risk patients for postoperative atrial fibrillation (POAF). METHODS: A total of 136 patients undergoing elective CABG and had > or =3 risk factors for POAF were prospectively randomized to one of three groups, to receive a single dose of amiodarone (5 mg/kg) and MgSO(4) (1.5 g) (combination group, n = 44), or an equal dose of amiodarone (amiodarone group, n = 44) or equal volumes of saline (control group, n = 48) at early postoperative period. Continuous electrocardiographic (ECG) monitoring was performed for the first 48 hours and an ECG was recorded every 8 hours later. POAF longer than 30 minutes or for any length requiring treatment, and the drug-related side effects were recorded. RESULTS: The study population showed a homogeneous distribution regarding risk factors for POAF and there was no significant difference in patient characteristics, echocardiographic variables, or operative variables among three groups. POAF developed in 4 patients in combination group, in 16 patients in amiodarone group and in 16 patients in control group, representing a 24% relative risk reduction between the combination group and control group (p = 0.023). No statistically significant difference regarding incidence of POAF was observed between amiodarone and control groups. CONCLUSIONS: Combined prophylactic therapy with amiodarone and MgSO(4) at the early postoperative period without a maintenance phase is an effective, simple, well-tolerated, and possibly cost-effective regimen to prevent POAF in normomagnesemic, high-risk patients.