The susceptibility of the aortic root: porcine aortic rupture testing under cardiopulmonary bypass

The association between commissural height and graft size selection in valve-sparing aortic root replacement†

OBJECTIVES

For selecting graft sizes in valve-sparing aortic root replacement (VSARR), commissural height is often referenced as a fixed variable; however, it may be affected by the diameter of the graft implanted. Using a novel aortic root sizer, we explored whether commissural height interacts with graft size.

METHODS

The novel sizer is a semi-translucent, rigid tube that is applied externally on the trimmed aortic root. It has 3 longitudinal slits with 120° orientation, which allows suspending the commissural stitches, symmetrically. The sizer is intended to identify the best graft size for a given anatomy by applying sizers of differing internal diameters, by which the quality of coaptation is inspected. Furthermore, each commissural slit is embedded with a ruler that allows measuring commissural heights. Using 5 normal porcine aortic roots with various annular diameters (23-31mm), we applied the 6 sizers in varying diameters (26, 28, 30, 32, 34 and 36 mm) on each of the root. We examined the correlations between the commissural height and baseline anatomical parameters and diameter of the sizer.

RESULTS

The commissural height correlated positively with annular dimension (r = 0.55, P = 0.002), free-edge length (r = 0.54, P = 0.002), geometric height (r = 0.51, P = 0.004) and negatively with diameter of the sizer (r = -0.75, P = 0.002). Binary linear regression models validated that the sizer's diameter negatively correlated with the commissural height after adjustments with each of the anatomical parameters (R2, 0.83-0.87; P < 0.001 for all).

CONCLUSION

Commissural height is not a fixed factor, but it interacts with the native aortic root size and the dimension of the implanted graft in VSARR.

Prosthesis-prosthesis anastomosis using barbed sutures compared to conventional sutures under high, long-term pressure; in vitro extracorporeal circulation setup

BACKGROUND

While barbed sutures have been extensively utilized in other disciplines, they have not been widely adopted in cardiac surgery. The lack of safety and feasibility data has limited its use within the field. To aide in the further understanding of how cardiac surgeons can use barbed sutures, we sought to develop a high-pressure in vitro simulation model. We compared knotless barbed sutures in a highly pressurized anastomosis to conventional sutures.

METHODS

Ten specimens in total were utilized in prosthesis anastomosis, using 34 mm Gelweave Plexus (Terumo Aortic, Sunrise, FL 33325, USA) and 34 mm Hemabridge (Intergard Woven Hemabridge, Getinge, Göteborg, Sweden). Five models of size 3-0 barbed suture anastomoses using non-absorbable, barbed, self-retaining, monofilament polypropylene sutures (Filbloc® 3-0, Assut Europe, Rome, Italy) were compared against five conventional anastomoses using size 4-0 polypropylene monofilament (Ethicon, USA). The systems were connected using a novel-designed extracorporeal circulation system. Pressure was rapidly increased in the specimen to a mean pressure of 300-350 mmHg, running then for a minimum of 48 hours to assess anastomosis strength and endurance.

RESULTS

No anastomotic dehiscence or rupture was recorded. Complex, angular anastomosis required extra stitch leakage sutures in both conventional and barbed suture specimens.

CONCLUSION

Using knotless barbed sutures with an additional self-locking maneuver for prosthesis-prosthesis anastomosis in cardiac surgery is feasible in an in vitro model under long term, high-mean pressure when compared to conventional sutures. In vivo trials should be performed to further validate the in vitro findings.