Volume 19 - Número 3

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OBJECTIVE: To present the functional, immunocytochemical and histopathologic results (in vitro or in heart specimens) after isolation, culture and co-culture of mesenchymal stem cells and skeletal myoblast cells transplanted and co-transplanted in experimental animals with ischemic heart disease and left ventricular ejection fractions lower than 40%. METHOD: We utilized 72 Wistar rats, divided into four groups according to the culture media or injected cells: control group into which only culture media was injected (22 rats); mesenchymal stem cell group (17 rats); myoblast skeletal cell group (16 rats) and co-culture group (17 rats). In the immunohistochemical studies, the cells were stained with anti-vimentin, anti-desmin and anti-myosin. In the histopathologic analysis, slides were stained with Gomori Trichrome, and neo-vessels and muscle tissues were identified. In the functional analysis the left ventricle ejection fraction was analyzed one week after myocardial infarction and one month after the injection. RESULTS: The initial left ventricle ejection fraction (control echo) was not statistically significant between the four groups (P=0.276), but was significantly different in the follow-up examination (P=0.001). This difference was seen between the control and the myoblast skeletal cells groups (P=0.037), between the control and the co-culture groups (P<0.001), and between the mesenchymal stem cell and co-culture groups (P=0.025). When the initial and final echocardiograms in each group were compared, the control group deteriorated (P=0.005) and the co-culture group improved (P=0.006). With the immunocytochemical in vitro analysis, mesenchymal stem cells were identified when stained with anti-vimentin and muscle cells when stained with anti-desmin. In the heart specimens, muscle tissue, stained with anti-desmin and skeletal myoblasts cells, stained with fast anti-miosin were identified. In the histopathologic analysis, new vessels were observed in the mesenchymal stem cell and skeletal myoblast groups, and muscular tissue, angiogenesis and myogenesis in the co-culture group. CONCLUSION: The left ventricle ejection fraction improved in the group in which muscle cells were injected and more strikingly in the co-culture group. The immunohistochemical findings in the culture and co-culture groups evidenced the corresponding cells. In the heart specimens, muscle and skeletal myoblast cells were found. In the histopathologic examination, new vessels and muscle tissue were found in the mesenchymal stem cell, skeletal myoblast cell and co-culture groups. Keywords: Cell transplantation; Myocardial infarction, therapy; Myocardium; Myocardial ischemia; Cell culture, utilization

OBJECTIVE: To study a bioprosthesis with discontinuation of the annular support, named the "Less Stented®" bioprosthesis. The Phase 1 objective was the "in vitro" study, during which the hemodynamic characteristics were analyzed. Phase 2 of this study consisted of an initial clinical implant protocol. METHOD: The "Less Stented" bioprosthesis consists in a glutaraldehyde treated bovine pericardium prosthesis manufactured by Braile Biomedica Ltda, São José do Rio Preto, São Paulo, Brazil, using the same manufacturing protocols as the stented bioprosthesis but with discontinuation of the annular suport. Bioprostheses were tested in a pulse simulator system and analyzed in cardiac simulator. with respect to the transvalvular gradient, regurgitant fraction and leakage volume, discharge coefficient, performance and efficiency index. The two patients of clinical protocol were analyzed according to the functional class (NYHA), an echocardiographic study and magnetic resonance, in both pre and postoperative periods. RESULTS: The transvalvular gradients ranged between 6.37 and 11.62 mmHg with a mean flow between 4.39 and 7.96 L/min, giving a good correlation (0.8291) on the regression curve with the increase in flow. The regurgitant fraction ranged between 10.95% and 17.94% and leakage volume between 4.49% and 7.87%. The discharge coefficient, performance and efficiency index showed favorable behavior with the flow increase, with good coefficient correlations for all three variables (0.9385, 0.9332 and 0.9024, respectively). The two patients submitted to "Less Stented®" bioprostheses implant presented good clinical evolutions. CONCLUSION: "Less Stented®" bioprostheses may represent a new alternative to aortic valve replacement. Keywords: Bioprostheses; Heart valve prosthesis; Aortic valve, surgery

OBJECTIVE: To compare patients who underwent the Bidirectional Glenn Operation with and without cardiopulmonary bypass (CPB), analyzing the characteristics and confirming if there is superiority of either of the employed techniques. METHOD: Between January 2002 and January 2004, 16 patients with complex heart defects were submitted to this operative technique. The mean age of the patients was 19 months and 14 were female. The patients were divided into two groups: Group A with seven patients (using CPB) and group B with 9 patients (without the use of CPB). Gender, age, mean pulmonary artery pressure (MPAP), CPB time, aortic clamping time, venoatrial shunt, previous operations, time in intensive care unit (ICU), total hospitalization time and immediate complications were all compared between the two groups. RESULTS: The median MPAP was 13 mmHg. In group A the CPB time was 91 ± 47 minutes (57-195 minutes), myocardial ischemia was 25 ± 33 minutes (0-80 minutes). Of these four patients required intracardiac procedures or enlargement of the pulmonary branches and in three, CPB assistance as ventilatory support was needed. In group B the venoatrial shunt was 21 ± 10 minutes (0-39 minutes). The time to extubation was 9 ± 13 hours with a median of 3 hours (1-43 hours). The ICU stay was 8 ± 12 days with a median of 5 days (1-50 days). Hospitalization was 12 ± 12 days with a median of 7 days (0-50 days). Five patients had been submitted to surgeries previously. Two, one patient from each group, died (12.5%). No neurological complications, pleural or pericardial effusions were observed. No significant differences were evidenced between the two groups in respect to all the variables studied. CONCLUSION: In spite of the relatively small cohort, this study suggests that the bidirectional Glenn operation can be performed with or without CPB giving similar results in respect to morbidity and mortality. Thus, the operation without CPB can be safely employed when the anatomic findings are appropriate and there is no severe hypoxia. Keywords: Heart defects, congenital, surgery; Pulmonary artery, surgery; Vena cava, superior, surgery; Extracorporeal circulation

OBJECTIVE: To determine predictors of postoperative bleeding after cardiac surgery, in order to focus on preventive measures for high-risk populations. METHODS: From October 2001 to March 2002, 411 consecutive adult cardiac surgery patients were prospectively studied, with the exception of those submitted to heart transplantation. In order to determine risk factors for postoperative bleeding, 20 preoperative, 17 operative and six postoperative variables were analyzed using univariate methods and multiple linear regression. RESULTS: Operative procedures included coronary artery bypass grafting in 227 (55.2%) patients, valvar operations in 198 (48.2%), aortic surgery in 25 (6.1%) and combined procedures in 60 (14.6%). Cardiopulmonary bypass was used in 335 (81.5%) patients and anti-fibrinolysis agents in 148 (36%). The thirty-day mortality was 5.6% (23 patients). Mean 24-hour postoperative blood loss was 610 ± 500 ml (range 10-4900). Re-exploration for bleeding was required in 15 (3.7%) patients. Independent predictors of postoperative bleeding were emergency operations (p=0.049), postoperative metabolic acidosis (p=0.001), preoperative thrombocytopenia (p=0.034) and prolonged cardiopulmonary bypass (p=0.021). CCONCLUSIONS: When possible, preoperative stabilization and correction of coagulation disturbances should be achieved in patients requiring urgent or emergent surgery and in those with thrombocytopenias. The duration of cardiopulmonary bypass should be minimized as long as this is practical. Postoperative metabolic acidosis must be actively corrected, especially the main determining cause. Keywords: Hemorrhage; Blood loss, surgical; Blood coagulation disorders; Risk factors; Cardiac surgical procedures; Postoperative complications; Multivariate analysis

OBJECTIVE: To assess a new technique of hemoconcentration and the necessity of blood derivative transfusion. METHOD: Eighty-six male (61.4%) and 54 female (38.6%) patients submitted to heart surgery under cardiopulmonary bypass were divided into two groups of 70 patients each according to conventional technique of blood preparation (Group A) and the use of the new technique of hemoconcentration. RESULTS: The hemoconcentration technique is feasible and did not alter the intra- and postoperative complications of the patients. The amount of blood and plasma used during and after cardiopulmonary bypass was less in Group B patients. Moreover, the fluid balance after cardiopulmonary bypassin this group was better when compared to the Group A patients. CONCLUSIONS: The new technique of hemoconcentration was efficient regarding removal of fluids, allowed a better use of oxygenator residual contents and decreased the amounts of blood derivatives used during and after cardiopulmonary bypass. Keywords: Hemofiltration, methods; Cardiac surgical procedures; Blood transfusion, autologous, method; Extracorporeal circulation, methods

OBJECTIVE: To analyze the results of techniques in the treatment of atrial fibrillation: the Maze procedure and Isolation of Pulmonary Veins were compared together with Control group, to establish the best treatment for this arrhythmia. METHOD: All patients were referred for surgery due for other cardiac lesions, which were treated concurrently. From July 1999 to September 2003, fifty-one patients where randomly allocated to the different groups. No cryoablation or other source of energy was used. The following variables were initially analyzed: total bypass time, aortic clamping time, sinus rhythm at discharge, and trans-operative and immediate post-operative complications. RESULTS: There were two intra-hospitalar deaths, one in the Maze group and one in the Isolation of Pulmonary Veins group. The Maze group had the longest bypass time (p<0,001). The duration of follow-up of 28.4 ±14 months was similar between the groups. The Isolation of Pulmonary Veins achieved the best results concerning reversion to sinus rhythm with 84.2% at hospital discharge and 88.9% after follow-up. In the Maze group, 78.5% of sinus rhythm was seen detected at discharge and 84.6% at the end of follow-up. In the Control group 87.5% of the patients have atrial fibrillation at discharge and after follow-up atrial fibrillation remained at 56.3% of the patients. There was no difference in the NYHA class between the groups after follow-up (p=0.56) and Control group patients had more complications (p=0.017). CONCLUSION: These results show that both techniques, the Maze and Isolation of Pulmonary Veins, have advantages over simple correction of cardiac lesions when associated to atrial fibrillation. Keywords: Atrial fibrillation; Mitral valve, surgery; Arrhythmia, surgery; Cardiac surgical procedures

OBJECTIVE: The "Cox-Maze III" operation is very effective in the treatment of chronic atrial fibrillation, but many surgeons do not use this technique because of its high complexity. In order to simplify the procedure, new alternatives that involve the use of different energy sources, such as radiofrequency, to create transmural lesions that substitute the atrial incisions of the Cox technique have been developed. The purpose of this study is to evaluate the results of intraoperative radiofrequency ablation in the treatment of chronic atrial fibrillation in patients with associated cardiac diseases. METHOD: Between February 2002 and March 2003, 35 consecutive patients with chronic atrial fibrillation were submitted to intraoperative radiofrequency ablation, associated with other surgical procedures. The ages of the patients ranged from 16 to 69 years old (mean 55.4 years old); there were 23 (65.7%) female patients. RESULTS: Radiofrequency ablation was associated with surgical treatment of the mitral valve in 29 (82.9%) patients and with treatment of atrial septal defect in six (17.1%). There was 1 (2.8%) in-hospital death; at the time of hospital discharge 26 patients (76.4%) were in sinus rhythm. After a mean follow-up of 11.7 ± 2.8 months, the overall survival rate was 94.2 % and 24 (72.7%) patients were in sinus rhythm. CONCLUSION: Intraoperative radiofrequency ablation is a safe and effective technique for the treatment of chronic atrial fibrillation, with satisfactory midterm results in terms of conversion to sinus rhythm. Keywords: Catheter ablation; Catheter ablation, radiofrequency; Atrial fibrillation; Intraoperative ablation

OBJECTIVE: To evaluate the effect on the left ventricular function of the early and late use of dopamine in an experimental model of an isolated heart. METHOD: Were used 60 rabbits in an isolated heart model sustained by animal support. An intraventricular balloon was placed in the left ventricle. Three groups were constituted: a control group (CG); a group that received dopamine precociously (Dopa P) and a group that received dopamine after 20 minutes (Dopa T). Direct and indirect hemodynamic readings were taken. RESULTS: Coronary artery flow: CG (7.196 ± 1.275 mL/min); Dopa P (9.477 ± 1.160 mL/min); Dopa T (14.316 ± 2.308 mL/min), with CG = Dopa P, CG ¹ Dopa T and Dopa P ¹ Dopa T. First intraventricular positive derivative of the pressure (dp/dt+): CG (719.61 ± 127.53 mmHg/s); Dopa P (719.61 ± 127.53 mmHg/s); Dopa T (1431.60 ± 230.87 mmHg/s), p<0.05, Dopa P¹Dopa T, CG=Dopa P and CG ¹ Dopa T. First intraventricular negative derivative of the pressure (dp/dt -): CG (469.85 ± 107.16 mmHg/s); Dopa P (716.07 ± 215.66 mmHg/s); Dopa T (931.24 ± 181.46 mmHg/s), p<0.05, Dopa P¹Dopa T¹CG. Delta V: CG (1.355 ± 0.2432 mL); Dopa P (0.97 ± 0.3199 mL); Dopa T (1.27 ± 0.2983 mL), p>0.05, Dopa P = Dopa T = CG. Developed systolic stress: CG (27.273 ± 10.276 g/cm2); Dopa P (55.219 ± 24.625 g/cm2); Dopa T (79.152 ± 12.166 g/cm2), Dopa P=Dopa T, Dopa P = CG and CG ¹ Dopa T. Malonic Dialdehyde (MDA): CG (4.5 ± 0.527 mmol/L); Dopa P (4.7 ± 1.16 mmol/L); Dopa T (4.1 ± 0.7379 mmol/L), p>0.05, Dopa P=Dopa T=CG. CONCLUSION: We concluded that, in the delineated experimental model, the early use of the dopamine was deleterious as shown by some hemodynamic variables. Keywords: Ventricular function; Myocardial ischemia; Dopamine; Models, animal

OBJECTIVE: The function of Intrinsic Cardiac Nervous System is largely unknown, as is its role in heart disease. In the digestive system, a topic aplication of Benzalkonium chloride (BC) leads to intrinsic denervation of the viscera. Thus, our aim was to obtain an experimental model of cardiac intrinsic denervation by the application of BC. METHOD: Thirty male Wistar rats received intrapericardic injection of CB 0.3% (CB animals) and thirty similar animals received saline (C animals). After 15 days the animals were divided in three groups, with 10 CB-treated and 10 saline-treated animals each. Group I was submitted to radiological and morphologic studies. The cardiac shadow area (CSA) and cardiothoracic index were calculated in roentgenograms with a semi-automatic image analysis system (MINI-MOP). The day after the animals were weighted and sacrificed with heart, liver and lung collected for histopathologic analysis. The animals of group II were submitted to a hemodynamic study. Measurements of blood pressure, heart rate and cardiac output were performed using the Cardiomax II termodilution system and a Termistor sensor. With the animals of the group III, the integrity of extrinsic parassympatic cardiac innervartion was examined by measuring heart rate response to electrical stimulation of the right vagus. Electrical activity was assessed by ECG. RESULTS: CB animals presented increases in cardiothoracic index, CSA, body and liver weight. In these animals the histopathologic analysis showed passive chronic congestion and reduction of the number of atrial neurons. In the hemodynamic study, total peripheral resistance and heart rate were similar in both groups, but blood pressure and cardiac index were reduced in the CB group. The vagal stimulation and ECG were similar in both groups. CONCLUSION: The Intrinsic Cardiac Nervous System denervation caused dilated cardiopathy in rats with left and right heart failure. The etiology of some dilated cardiopathies in human is largely unknown. Thisunpublished experimental model should provide future studies with the objective of elucidating the relationship between neuronal injures and heart disease. Keywords: Myocardial contraction; Heart conduction system; Autonomic nervous system; Ganglia, parasympathetic; Autonomic denervation; Benzalkonium compounds; Cardiomyopathy, congestive; Heart failure, congestive

A 16-year-old female patient, with a congenital heart defect (interatrial communication) underwent heart surgery. She evolved with complications in the immediate postoperative period with sudden hemorrhagic hypotension and progressive loss of sight in both eyes. In the postoperative period there was a high intraocular pressure and optic disk edema. Optic atrophy and irreversible bilateral blindness was confirmed 21 days after heart surgery despite treatment. In two years of follow-up, the patient is completely blind with irreversible optic atrophy Keywords: Amaurosis; Blindness; Cardiac surgical procedures, adverse effects; Postoperative complications; Optic nerve diseases, etiology

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