Dispositivo de anastomose magnética de óstios coronarianos: idealização, desenvolvimento e prototipagem

Abstract

MAGNETIC ANASTOMOSIS DEVICE OF CORONARY OSTIA: IDEALIZATION, DEVELOPMENT AND PROTOTYPING Introduction. The anastomosis of coronary ostia with aortic prosthesis is a crucial part of aortic root reconstruction surgery because it is associated with morbidity and mortality resulting from this procedure. A device for magnetic anastomosis of the coronary ostia could diminish variability of techniques used, surgical time and surgical learning curve, as well as avoiding transfixation transfusion of the tissue of the vessels. Objetcive. To idealize, to develop, to prototype and to mechanically evaluate devices of magnetic anastomosis of coronary ostia. Methods. The design of the device was based on theoretical knowledge related to the anatomy, the construction of adequate anastomoses and the magnetic properties. Prototypes were then printed three-dimensionally. An experimental in vitro study then mechanically evaluated two versions of magnetic anastomosis and a manual suture between Dacron® prostheses and pig coronaries. The evaluation consisted of tensile tests to measure the limits of tensile strength (LTS). Three groups were compared: anastomosis with the third version of the device (V3), with small magnets in arms coming from the central ring; anastomosis with the fourth version of the device (V4), which has a larger central ring-shaped; and manual suture anastomosis. Data from the three groups were compared, regarding the limits of tensile strength, thickness and diameter of the coronary buttons. Results. Values of thickness and diameter were similar among test groups. LTS values showed a statistically significant difference in the comparison between each of the test groups (F = 73,095, p <0,01). The V4 device exhibited the greater LTS among magnetic anastomoses, while suture had the best performance of all (0.76 ± 0, 13 kgf and 1.72 ± 0.35, respectively, mean ± standard deviation). In a linear regression model, diameter and thickness did not show an important association with limits of tensile strength. Key Findings. The anastomosis of the coronary buds with manual suture showed tensile strength superior to the anastomoses with the two device versions evaluated, so that the manual suture is a safer procedure. However, there are no defined thresholds of tensile strength below which an anastomosis would be unsafe.