Xyphoid MIDCAB: Report of the technique and experience with a less invasive MIDCAB procedure

(#1999-16834)

Adilson Casemiro Pires, Wladimir Faustino Saporito, Luís Eduardo Villaça Leão, Vicente Forte, Sigmar Horst Cardoso, Osiris Ramaciotti

Paulista Medical School, São Paulo Federal University and ABC Medical School, São Paulo, SP, Brazil

ABSTRACT

Background: The use of glutaraldehyde preserved bovine pericardium in valvular prostheses is well known. Although widely used clinically as patch material, bovine pericardium has not been extensively studied in this setting.

Methods: With this objective, 21 dogs received a standard bovine pericardial patch to partially replace the aortic, left atrial, or pericardial walls. The dogs were randomly divided into three groups according to implant duration. Group 1 consisted of 6 dogs evaluated surgically after 33 to 43 postoperative days, Group 2 with 7 dogs reoperated after 120 to 165 days, and Group 3 with 8 dogs reoperated after 225 to 305 days.

Results: Microscopic and macroscopic evaluation demonstrated: 1) the wrinkled surface of the bovine pericardium adhered to neighboring structures whereas the smooth surface did not adhere to the epicardium; 2) the bovine pericardial patch did not show structural changes in any of the implant sites; 3) the final left atrial patch was significantly smaller than the aortic and pericardial patches for Group 2 and Group 3 dogs; 4) the atrial patch area decreased significantly, whereas the aortic and pericardial areas did not change over time; 5) the pericardial implant was significantly thinner than the aortic and left atrial patches for Group 3 dogs; 6) a layer of fibrous connective tissue was formed on the smooth surface of the left atrial and aortic patches. The internal apposition fibrasis was significantly thicker in the left atrium than in the aorta in Groups 1 and 2; 7) the internal fibrasis layer of the atrial and aortic patches was calcified in Groups 2 and 3; and 8) the internal apposition tissue of the atrial and aortic patches showed neoformation of elastic fibers which clearly increased with implant duration.

Conclusions: The fate of implanted glutaraldehyde-preserved bovine pericardial patches in cardiovascular applications depends on three factors: 1) the contact surface, 2) the tension it is subjected to, and 3) contact with blood flow.

AUTHOR/ARTICLE INFORMATION

Reprint requests to: Adilson Casemiro Pires, Av. George Corbisier, 845 - Cj. 204, Jabaquara, São Paulo - SP, Brazil, CEP: 04043-000