TSRA Content:
Author: Aakash M. Shah, MD
This is a revision and update from the previous edition of the TSRA Primer in Cardiothoracic Surgerywritten by Timothy Pirolli, MD, and Sanford Zeigler, MD.
Suturing the Anastomosis
The coronary anastomosis always requires a distal anastomosis to the coronary artery and, for free-standing grafts, a proximal anastomosis to the aorta. Despite subtle differences in technique for proximal vs. distal anastomoses, they are both end-to-side anastomoses and are generally performed the same way. The distal anastomosis is performed first. The conduit is prepared by trimming the distal end to have approximately a 30-degree bevel. The resultant orifice is visualized as a clock with the distal-most portion (the tip of the hood) referred to as the “toe” and the proximal-most portion (the shorter end of the bevel) referred to as the “heel” (Figure 1). The orifice is further opened at the “heel” with a vertical slit. The corresponding coronary artery is prepared with a linear slit similar to length to the conduit orifice.
The distal anastomosis is typically sewn together using a double-armed, 7-0 Prolene suture with a Castro-Viejo needle driver and a pair of Gerald forceps by the surgeon and is performed using the parachute technique. The assistant holds the conduit between their fingers or with two atraumatic forceps to expose the full lumen for the suturing surgeon. The anastomosis is begun at the “heel” and after a few stitches between the conduit and coronary artery, the conduit is parachuted down to the coronary artery. Both ends of the suture should be equal in length, and the end closer to the assistant is clamped with a shod and set aside. The end closer to the surgeon is used to continue the anastomosis with forehand bites. At the “toe”, the surgeon can either continue the anastomosis with the same prolene arm towards the “heel” using backhand bites or use the other clamped arm of the suture and continue the anastomosis towards the “toe” in the other direction with forehand bites. Once the suture reaches the segment of the coronary opposite to the original bite on the conduit, the suturing is complete, the needles are cut off.
Final Assessment of Distal Anastomosis
Prior to tying the distal-end suture, the graft should be flushed to de-air and remove any debris. The left internal mammary artery (LIMA, typically used for the left anterior descending coronary bypass) may be flushed by temporarily releasing the bulldog clamp. Venous or radial grafts may be flushed with heparinized saline, heparinized blood or cardioplegia. Some surgeons use a nerve hook to tighten the suture all the way around prior to tying. Once the surgeon is satisfied with the anastomosis, the suture is tied down. Any leaks at the anastomosis are repaired with an individual 7-0 Prolene in an interrupted fashion. For LIMAs, the fascial “wings” of the pedicle are secured to the heart on each side of the anastomosis with a single 6-0 Prolene, with careful attention to avoid injury to any coronary branches.
In most anastomoses, only 12 suture passes, along each hour of the clock, are needed. Throughout the anastomosis, the goal should be to accurately approximate the conduit and coronary artery orifices while maintaining small, equal distances between suture bites to avoid leaks and narrowing of the vessel.
Conduit Positioning and Proximal Anastomosis
The graft length is sized by allowing the heart to distend with blood (tell the perfusionist to "fill the heart”) and laying the conduit towards the ascending aorta in a path that does not allow for kinks or compression. The final conduit should be tension free with a natural lie. Once the course is selected, the heart can be emptied, and the proximal angle can be fashioned with 1-2 cm of extra graft length. The vein graft should be marked with a line down its length, and this line should be used to prevent twists or kinks. The proximal anastomosis is then performed. The aortic opening should be fashioned with a small, linear incision (3-4mm in length) with an #11 blade followed by a hole-punch through the slit to create a circular orifice (carefully removing the punched-out piece of aorta to prevent its entry into the aorta, which could then embolize). Care should be taken with direct palpation to avoid any firm or calcified areas of the aorta. The proximal end of the graft should be fashioned to have a large, wide hood with a 30-degree angle relative to the aorta. The proximal end of the graft should be about 20% larger than the orifice of the aorta. The proximal end of the graft is sutured to the aortotomy with a 6-0 Prolene suture in a parachute technique similar to the distal anastomosis. Large full-thickness bites should be taken on the aortic side to secure the anastomosis and minimize chance of dissections. Many surgeons secure circular, radio-opaque markers around the proximal anastomosis within the knot of the suture.
Figure 1: Illustration of coronary artery anastomosis technique (either proximal or distal) demonstrating the heel and the toe.
References:
Goss, S.G., Salvatore, D.M. (2018). Fundamentals of Vascular Anastomosis. In: Palazzo, F. (eds) Fundamentals of General Surgery. Springer, Cham. https://doi.org/10.1007/978-3-...