Objective: The saphenous vein (SV) used in coronary artery bypass grafting is submitted to elevated and continuous shear stress. Occlusion of the grafts can occur in response to the new hemodynamic conditions. The aim of this study is to compare the precocious structural and molecular (cDNA) changes in saphenous veins grafts submitted to low pressure hemodynamic conditions versus systemic hemodynamic conditions. Method: Forty sections of SV were cultivated "ex-vivo" under venous hemodynamic conditions (VHC) (without pressure, flow: 5 mL/min) and under arterial hemodynamic conditions (AHC) (pressure: 80 mmHg, flow: 50 mL/min). The following variables were analyzed: cellular viability (MTT assay) cellular density (Hoechst 33258 staining) and apoptosis (TUNEL assay), before the procedure and one, two and four days after the procedure. "cDNA microarray" analysis of the SV sections was used to determine the precociously changed molecular targets in the veins cultivated under arterial conditions. The identification of these targets was achieved using a RNA homogenized pool of these vein sections, interacting on slides with 16,000 predetermined human genes (Agilent Technologies slide). The genes with changed expressions were verified by real time PCR in the veins of 16 patients. Results: There was a gradual reduction in the cellular density and in the tissue viability in the saphenous veins cultivated under AHC, whereas no alterations were observed in the saphenous veins cultivated under VHC of up to four days. In the AHC group there were signs of a cellular apoptotic process (positive-TUNEL) from the first day after cultivation. In the VHC group these alterations were not observed. Although the cellular density was the same in the veins submitted to arterial conditions, after 24 hours of cultivation, many cells already showed signs of the apoptotic process. The Oncogene 3 and the Interleukin 1ß were the most common sites with alterations identified in this research. The Oncogene 3 expression was elevated in 11 (68.7%) of the veins cultivated under AHC, and the Interleukin 1ß expression was elevated in 9 (56.2%) of these vein sections (p<0.05). Conclusion: The "ex vivo" study model was able to mimic events that occur "in vivo" by SVs utilized in the coronary artery bypass grafting. In the AHC group precocious loss of cellular viability (apoptosis) and significant elevation in the Oncogene 3 and Interleukin 1ß gene expressions were observed. The long-term follow up of these patients is important to determine the real effect of these immediate changes in the patency of the vein grafts.

Midterm follow-up with exclusive use of arterial grafts in complete myocardial revascularization of patients with triple vessel coronary artery disease Seguimento clínico a médio prazo com uso exclusivo de enxertos arteriais na revascularização completa do miocárdio em pacientes com doença coronária triarterial

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 6 (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.

No abstract