Comparison of the internal thoracic artery flow dissected by video endoscopy or conventional technique

ABSTRACT Purpose: To compare the blood flow in the internal thoracic artery when dissected endoscopically in a conventional manner, in addition to develop a reliable experimental training model for the surgical team. Methods: Paired experimental study. Ten pigs were operated and had both internal thoracic arteries dissected, the right with a conventional technique and the left by video endoscopy. The main outcomes to be studied were flow, length, and time of dissection of each vessel. Results: Blood flow measurements were performed with mean heart rate of 100 ± 16 bpm and mean arterial pressure of 89.7 ± 13 mm Hg. The mean blood flow of endoscopic dissection of the internal thoracic artery was 170.2 ± 66.3 mL/min and by direct view was 180.8 ± 70.5 (p = 0.26). Thus, there was no statistically significant difference between the flows, showing no inferiority between the methods. Conclusions: The minimally invasive dissection of the internal thoracic artery was shown to be not inferior to the dissection by open technique in relation to the blood flow in the present experimental model. In addition, the model that we replicated was shown to be adequate for the development of the learning curve and improvement of the endoscopic abilities.

Experimental model for the study of chronic renal ischemia in rats: morphologic, histological and ultra-structural analysis / Modelo experimental para o estudo da isquemia renal crônica em ratos. Análises morfológica, histológica e ultra-estrutural

PURPOSE: To evaluate a model of chronic renal ischemia in rats and to characterize the effects on renal tissue. METHODS: 168 Wistar rats were divided into two equal groups, control (GC) and ischemia (GI). The animals of the GI (n=84) were submitted to partial ligation of the left renal artery, and the animals of GC (n=84) stayed with the renal artery intact. In seven successive and identical periods of time, in weekly intervals, 12 animals of each group were submitted to nephrectomy, with morphometric determinations and histological and ultra-structural analysis. RESULTS: The GI presented progressive reduction in renal weight, volume and cortical thickness observed from the 7th day of the experiment, reaching maximum degree in the 49th day (p < 0.05). The proximal tubular atrophy in the GI was observed in 75/84 analysis (89,2 percent), with highly significant difference among the groups starting from the 7th day (p=0 .0009) and in the other periods of the experiment (p=0 .00001). The most prevalent interstitial alteration was the infiltrate, present in 98,8 percent of the GI, with highly significant difference among the groups in the whole experiment (p=0 .00001). Ultra-structural analysis didn't demonstrate glomerular lesions, evidencing that the glomerule preserves its intact architecture during chronic ischemia. CONCLUSION: The model showed that chronic renal ischemia in rats provokes progressive renal atrophy, with preservation of glomerular structure.(AU)

OBJETIVO: Avaliar um modelo de isquemia renal crônica em ratos e caracterizar os efeitos no tecido renal. MÉTODOS: Utilizaram-se 168 ratos Wistar divididos em dois grupos iguais, controle (GC) e isquemia (GI). Os animais do GI (n=84) foram submetidos à ligadura parcial da artéria renal esquerda, e os animais do GC (n=84) permaneceram com a artéria renal intacta. Em sete períodos de tempo sucessivos e iguais, em intervalos semanais, 12 animais de cada grupo foram submetidos à nefrectomia, com determinações morfométricas e análises histológica e ultra-estrutural. RESULTADOS: O GI apresentou redução progressiva no peso, volume e espessura cortical renal a partir do 7º dia do experimento, atingindo grau máximo no 49º dia (p < 0.05). A atrofia tubular proximal no GI ocorreu em 75/84 análises (89,2 por cento), com diferença altamente significativa entre os dois grupos a partir do 7º dia (p=0.0009) e nos demais períodos do experimento (p=0.00001). A alteração intersticial mais comum no GI foi o infiltrado, presente em 98,8 por cento, com diferença altamente significativa entre os dois grupos (p=0.00001). A análise ultra-estrutural não demonstrou lesões glomerulares, evidenciando que os glomérulos preservam sua arquitetura intacta durante a isquemia crônica. CONCLUSÃO: O modelo mostrou que a isquemia renal crônica em ratos provoca atrofia renal progressiva, com preservação da estrutura glomerular.(AU)