Laura Barboza

Double skeletonized internal thoracic artery vs. double conventional internal thoracic artery in diabetic patients submitted to OPCAB

OBJECTIVE To evaluate the influence of the technique used in the dissection of thoracic arteries in the evolution of diabetic patients submitted to OPCAB. METHODS Seventy diabetic patients submitted to OPCAB using bilateral thoracic arteries were evaluated. In Group A, thoracic arteries were dissected as a pedicle, while in Group B they were skeletonized. RESULTS The mean age of patients in Group A was 52.14 +/- 7.35 years old versus 55.71 +/- 8.1 years for Group B (p=0.057). In Group A, six patients (17.1%) were insulin dependent against nine (25.7%) in Group B (p = 0.561). The EUROSCORE was 3.97 +/- 2.49 for Group A opposed to 4.14 +/- 3.06 for Group B (p = 0.879). The number of distal anastomoses in Group A was 3 +/- 0.77 versus 3.03 +/- 0.89 in Group B (p = 0.981). Three patients (8.57%) from Group A presented with mediastinitis. Insulin dependence was the only significant risk factor (p=0.008) for mediastinitis. In this group the use of skeletonized internal thoracic arteries significantly decreased the incidence of mediastinitis (p = 0.044). CONCLUSION The incidence of mediastinitis was lower in the group for which mammary arteries were dissected using skeletonization. Among insulin-dependent diabetics, 50% of the patients from the group in which the pedicled internal thoracic artery was utilized presented with mediastinitis; the utilization of skeletonized internal thoracic arteries significantly decreases the incidence of mediastinitis.

Are purified or expanded cord blood-derived CD133+ cells better at improving cardiac function?

Endothelial progenitor cells (EPCs), which express the CD133 marker, can differentiate into mature endothelial cells (ECs) and create new blood vessels. Normal angiogenesis is unable to repair the injured tissues that result from myocardial infarction (MI). Patients who have high cardiovascular risks have fewer EPCs and their EPCs exhibit greater in vitro senescence. Human umbilical cord blood (HUCB)-derived EPCs could be an alternative to rescue impaired stem cell function in the sick and elderly. The aim of this study was to purify HUCB-derived CD133+ cells, expand them in vitro and evaluate the efficacy of the purified and expanded cells in treating MI in rats. CD133+ cells were selected for using CD133-coupled magnetic microbeads. Purified cells stained positive for EPC markers. The cells were expanded and differentiated in media supplemented with fetal calf serum and basic fibroblast growth factor, insulin-like growth factor-I and vascular endothelial growth factor (VEGF). Differentiation was confirmed by lack of staining for EPC markers. These expanded cells exhibited increased expression of mature EC markers and formed tubule-like structures in vitro. Only the expanded cells expressed VEGF mRNA. Cells were expanded up to 70-fold during 60 days of culture, and they retained their functional activity. Finally, we evaluated the therapeutic potential of purified and expanded CD133+ cells in treating MI by intramyocardially injecting them into a rat model of MI. Rats were divided into three groups: A (purified CD133+ cells-injected); B (expanded CD133+ cells-injected) and C (saline buffer-injected). We observed a significant improvement in left ventricular ejection fraction for groups A and B. In summary, CD133+ cells can be purified from HUCB, expanded in vitro without loosing their biological activity, and both purified and expanded cells show promising results for use in cellular cardiomyoplasty. However, further pre-clinical testing should be performed to determine whether expanded CD133+ cells have any clinical advantages over purified CD133+ cells.

Revascularização do miocárdio sem circulação extracorpórea em pacientes submetidos à hemodiálise

OBJECTIVE To analyze the hospital outcomes of patients, with chronic renal insufficiency in the hemodialysis, submitted to OPCAB. METHOD Fifty-one patients with chronic renal insufficiency were submitted to OPCAB. Hemodialysis was performed on the day before and the day after the operation. Myocardial revascularization was performed using LIMAs suture and suction stabilization. RESULTS Fifty-one patients, with an average of 61.28+/-11.09 years, were analyzed. Thirty patients (58.8%) were female. The predominant functional class was IV in 21 (41.1%) of the patients. The left ventricle ejection fraction was dire in 21 (41.1%) patients. The mean EUROSCORE of this series was 7.65+/-3.83 and the mean number of distal anastomosis was 3.1+/-0.78 per patient. The average time of mechanical ventilation was 3.78+/-4.35 hours and the mean ICU stay was 41.9+/-13.8 hours, while the average hospitalization was 6.5+/-1.31 days. In respect to complications, nine (17.6%) of the patients developed atrial fibrilation, and one (1.9%) patient presented with a case of ischemic stroke but had a good recovery during hospitalization. There were no deaths in this series. CONCLUSION Chronic renal patients submitted to hemodialysis were always a high risk population for myocardial revascularization. In this series, the absence of extracorporeal circulation appeared to be safe and efficient in this special subgroup of patients. The operations were performed with low indices of complications, absence of deaths and relatively low stays in the ICU and in hospital.

Influência da estimulação biatrial temporária externa na prevenção da fibrilação atrial no pós-operatório de revascularização miocárdica sem circulação extracorpórea

BACKGROUND: Atrial fibrillation is the most common complication after myocardial revascularization, and it increases morbidity/mortality. OBJECTIVE: The purpose of this prospective randomized study was to test the hypothesis that temporary biatrial pacing is effective in reducing the incidence of postoperative atrial fibrillation after myocardial revascularization. METHODS: Ninety-eight non-consecutive patients who had undergone off-pump myocardial revascularization received two temporary electrodes attached to the right and left atria, which were connected to either pair of atrial pacemaker electrodes, in addition to the leads implanted in the right ventricle. Two groups of patients were randomized (control: 49 patients with no biatrial pacing; therapeutic: 49 patients with biatrial pacing). The variables of interest were atrial fibrillation (present or absent) and length of hospital stay. RESULTS: The incidence of atrial fibrillation was 36.73% in the control group and 14.29% in the therapeutic group (p=0.0194). Length of hospital stay was 7.00 ± 2.82 days for patients with no atrial fibrillation (n=73) and 9.20 ± 2.87 days for patients with atrial fibrillation (n=25) (p=0.0001). Age was an important predictor of arrhythmia and ranged between 62.34 ± 9.00 years in the group with no atrial fibrillation and 67.20 ± 7.42 years in the group with atrial fibrillation (p=0.0170). CONCLUSION: Compared to controls, prophylactic temporary biatrial pacing is effective in preventing atrial fibrillation. Hospital stay was longer for patients who developed postoperative atrial fibrillation, and age was an important predictor for the development of arrhythmia.

Off-pump coronary artery bypass grafting with arterial grafts: analysis of 300 cases

Objective: The present study reviews our immediate results of off-pump coronary artery bypass grafting using only arterial grafts. Method: Between June 2000 and December 2004, 300 patients were submitted to off-pump myocardial revascularization using only arterial grafts. The left internal mammary artery was the first-choice graft, followed by the radial artery and the right mammary artery. Results: The ages of the patients ranged from 33 to 77 years, with 234 male and 66 female. In respect to risk factors for coronary disease, 77% had hypertension, 66% had a history of smoking, 53% had high levels of cholesterol and 21% had diabetes. Eighty-four patients (28%) had a history of myocardial infarction and 77 (25.6%) were using endovenous nitroglycerin in the preoperative period. The ejection fraction was less than 30% in 77 (25.6%) patients. A total of 189 patients had multi-vessel disease. The EuroSCORE ranged from 0 to 12 points with an expected mortality rate of 3.7%. The total numbers of distal anastomoses were 838, with a mean of 2.79 ± 0.97 anastomoses per patient. There were six deaths in this series, one caused by renal failure, one caused by metabolic disorders, two caused by mediastinitis, one caused by pneumonia and one caused by bleeding. Diabetes was the only factor associated with mortality. Conclusion: The use of arterial grafts in off-pump myocardial revascularization did not increase the immediate morbidity or mortality in this series. The results were similar to the results predicted by the EuroSCORE. The use of only arterial grafts in diabetic patients must be carefully evaluated.

Analysis of the immediate outcomes of a comparative randomized study between aorto-saphenous mechanical anastomosis versus conventional anastomosis

OBJECTIVE To evaluate the immediate results of mechanical aorto-saphenous anastomosis compared with conventional anastomosis. METHOD We evaluated 12 patients. The mean age ranged from 62.33 +/- 7.30 years. Of 12 patients submitted to surgery without extracorporeal circulation, 10 (83.3%) patients were male. Thirty-three proximal anastomoses were evaluated, 21 of them being performed through the conventional manner and 12 with the St. Jude Symmetry aortic connector. The time spent on anastomosis, and free flow and patency on the 4th day postoperative were analysed. RESULTS The mechanical anastomosis was successfully performed in all patients. Electrocardiographic alteration compatible with myocardial infarctation (MI) on the 2nd day postoperative was observed only in one patient. The patient was referred to angiographic restudy, becoming evident a conventional proximal anastomosis occlusion for the marginal branch. Three patients had atrial fibrillation. The average time spent to perform the mechanical anastomosis was 44.08 +/- 9.26 seconds against 3.86 +/- 0.61 minutes of the conventional anastomosis (p = 0.0022). The average blood free flow observed in the mechanical anastomosis was 302.75 +/- 82.76 mL/min versus 190.75 +/- 51.53 mL/min (p = 0.0022). In the angiographic restudy performed on the 4th postoperative day, it was detected the occlusin of three mechanical anastomosis. There was no new conventional anastomosis (p = 0.2500). CONCLUSION The present study showed a statistically significant superiority for mechanical anastomosis of the saphenous vein with the aorta when evaluated the blood free flow and the time to perform the anastomosis. In relation to the artery condition in the postoperative angiography, one cannot say there was statistically significant difference between the procedures studied.