BACKGROUND: to evaluate the influence of diameter and time on the patency of transthoracic pericardial window in normal pericardium. METHODS: Thirty-six mongrel dogs were divided into 6 groups: 1a, 1b and 1c; 2a, 2b and 2c; n=6 per group. In groups 1a, 1b and 1c the pericardial window diameter was 2cm and in groups 2a, 2b and 2c it was 4cm. Animals were sacrificed 2, 8 and 12 weeks , respectively and we evaluated the patency and histology of the pericardial margins. RESULTS: Eighty-nine per cent of the windows were open and 11% were completely obstructed by pericardial-epicardic adhesions. In the groups with a 2cm-pericardial window, we observed during sacrifice an increase of the original diameter in 89% of the animals. In dogs with a 4cm-pericardial window a greater diameter was observed in 61% of the animals. We did not observe statistical differences comparing animals with the same window diameter but sacrificed at different time points. Likewise, we did not observe differences among dogs with different window diameters but sacrificed at the same time points. The degree of pericardial-epicardic adhesions, according to a graduation score, was not different among the groups when analyzing the influence of time and diameter, except for the group 2b ( 4cm-window diameter and animals sacrificed at 8 weeks). Histopatology was not different among the different groups. We did not observe any lung blockade of the transthoracic pericardial windows. CONCLUSIONS: time and diameter did not influence the patency of the transthoracic pericardial window.
Pericardium; Pericardial effusion; Pericardial window techniques; Dogs
