S2 connector versus suture: distal coronary anastomosis remodeling, patency, and function in the pig.

BACKGROUND Anastomotic connectors could be the key to less invasive bypass surgery, including endoscopic procedures, but equivalence to conventional suturing needs to be established. A novel distal coronary connector was tested pre-clinically for safety and efficacy in comparison to conventional suturing. METHODS AND RESULTS Left internal thoracic to left anterior descending coronary artery bypasses were constructed off-pump in 35 pigs (73+/-8 kg). An intraluminal metal connector (S2AS) was used in 21 and conventional suturing in 14 animals. S2AS anastomosis construction was easier achieved in one-fourth of the conventional construction time (3.7+/-0.7 versus 16.5+/-2.6 minutes; P<0.001). Acute patency tended to be better (P=0.15). All anastomoses were evaluated intraoperatively, and subgroups at 90 and at 180 days. Patency was 100%. An effective remodeling response was observed in all groups, resulting in unobstructed anastomoses with excellent hemodynamic performance (fractional flow reserve > or = 0.93 at 180 days). At 6 months, the noncompliant connector was covered with stabilized neointima that was thinner than found on the suture line (0.10+/-0.04 versus 0.31+/-0.13 mm; P=0.01). The connector induced less lumen loss (-0.6+/-6.5 versus 21.6+/-19%; P=0.03). The initial side-to-side configuration had remodeled to an end-to-side shape as intended. CONCLUSIONS In the porcine model, the connector rapidly and consistently produced high-quality anastomoses that fully met current standards on patency and function. Unconventional aspects like a noncompliant intraluminal ring and a side-to-side to end-to-side converted configuration did not interfere with favorable anastomosis remodeling. These findings shed a new light on the anatomical prerequisites for anastomosis patency.