10 essential principles when constructing a coronary anastomosis
- 1.
Avoid any manipulation of the endothelium.
- 2.
Use both hands: for a right-handed surgeon, the left hand provides exposure while the right hand places sutures.
- 3.
Ensure the full range of motion (360 degrees) of the needle in the needle holder to allow for adequate angulation.
- 4.
Sutures must follow a path that goes from inside to outside in the coronary target.
- 5.
Needle repositioning must be completed in proximity to the anastomosis and after each pass of the needle.
- 6.
Spacing of sutures must be homogenous and consistent.
- 7.
Always use a parachuting technique.
- 8.
Finalize the construction of the anastomosis on the surgeon’s side.
- 9.
Never tie the suture at the heel or the toe of the anastomosis.
- 10.
Always unclamp or inject the graft while trying to avoid purse stringing the anastomotic suture line.
Introduction
Sequential anastomotic technique allows for greater use of conduit length, may improve graft patency, and allow for more complete revascularization with a better economy of conduit utilization . In this chapter, we will discuss current techniques for constructing different types of sequential anastomoses. We will also explore different grafting strategies including the creation of composite grafts, and when and how to use an anaortic technique, as well as technical considerations related to conduit size and an on- versus off-pump approach.
We have focused this chapter on key technical considerations when using the multiple techniques available for the creation of sequential anastomoses. These considerations include the importance of accounting for the size and length of the conduits; the choice of an on- versus off-pump approach; the degree of coronary stenosis at each of the distal targets; the location of the target vessels and, the type of connection (e.g., Y or T graft) between these conduits. Each of these factors will influence the surgeon’s ability to achieve complete revascularization and a successful operation with minimal risk to the patient.
Not all surgeons will be familiar with the techniques described in this chapter. Adopting these techniques will represent a paradigm shift for some operators. We have provided a detailed description of the techniques so they can be adopted progressively and safely by most practicing surgeons and residents or fellows in training. The surgical expertise needed to master these procedures can only be acquired through experience and repetition.
The final decision of how to complete a given operation must, of course, be left to the judgment of the operating surgeon. Our intention is to equip that surgeon with a wider array of surgical techniques in order to expand the options for planning and carrying out surgical coronary revascularization.
Types of sequential anastomoses
In order to implement sequential grafting into your usual practice, it is important to have several methods for construction anastomoses in your clinical armamentarium. This is not the time to take a one-size-fits-all approach. A coronary artery bypass grafting (CABG) procedure using sequential grafting requires planning before and during the operation, and the flexibility to improvise when unexpected issues such as short conduits or difficult targets present themselves.
When constructing the side-to-side anastomoses in a sequential graft, latero-lateral or diamond-shaped anastomoses are used, depending on the intersection of the conduit and target. For the distal anastomosis a T-shaped or termino-lateral anastomosis can be used. Finally, when a conduit has insufficient length, a termino-terminal anastomosis can be constructed to elongate it. We will describe our approach to each anastomotic technique, with labeled diagrams to help readers understand the geometry of the graft and target vessel.
There are some general principles that apply to the construction of the anastomoses described here. Adhesions or fascia should be removed from the conduit prior to use. It is our preference to use a 15-blade to incise the epicardium, and a very sharp blade (Sharpoint, 30 degree, Stab Knife Straight) or 11 blades for arteriotomies. For suturing, 8-0 prolene is used for most arterial conduits, while 7-0 is used for saphenous vein grafts and larger radial arteries. The suture is always from outside to inside on the conduit and from inside to outside on the coronary artery. At the time of tying, there must be low-pressure flow through the conduit—either by removing the bulldog or by injecting the conduit—to avoid purse stringing the anastomotic suture line.
Latero-lateral anastomosis
A latero-lateral anastomosis can be used on any territory. Most commonly this type of anastomosis is used when bypassing a diagonal branch of the left anterior descending (LAD) with the left internal thoracic artery (LITA).
Graft kinking is a particular concern when constructing a latero-lateral anastomosis, and there are several considerations when choosing this technique. It is important to ensure that there is sufficient graft length and that the angles distal and proximal to the anastomosis are not too acute. The intended site of the anastomosis is chosen based on the location of the coronary target, but one must also consider the location of any additional sequential anastomoses to avoid kinking of the graft. When the coronary targets are very close together, the latero-lateral technique should be avoided in favor of a diamond-shaped anastomosis to avoid kinking. The use of the baby Y composite grafting technique is an excellent alternative.
It is useful to have an assistant gently hold the conduit on both sides of where the incision will be made, ensuring that undue twisting is avoided and proper orientation is maintained. The coronary epicardium is incised using a 15-blade knife. An arteriotomy is made on the coronary artery using an approximate length of 4–5 mm. The graft is placed under gentle pressure either by injecting it with a syringe or, if in situ, by placing a bulldog distally and proximally to the anastomotic location. The conduit is then opened using a Beaver blade knife, paying close attention to not insert the blade so deep as to open the back wall of the conduit. The incisions on the conduit and on the coronary target should be approximately the same length.
The anastomosis is started on the toe of the conduit ( Fig. 9.1 ) with the suture from the outside of the conduit toward the inside. A bite is then taken on the coronary artery at the toe on the right side of the arteriotomy (side closest to the surgeon) from the inside out. Bites are continued 1–2 mm apart from each other along the respective posterior walls of the arteriotomies of the coronary artery and conduit. This side of the anastomosis is most easily done backhand or using the needle in a hook position. Care must be taken at the heel of the conduit not to hit the back wall. Once this posterior wall has been completed, the conduit is parachuted down. A fine hook is used to tighten each loop of suture. The anastomosis is then completed on its anterior aspect (side closest to the surgeon) toward the toe in a forehand technique.
Diamond-shape anastomosis
The diamond-shaped anastomosis is most often used on the lateral, posterior, and inferior walls. This technique is used when the course of the conduit must remain perpendicular to the coronary artery. On the lateral wall this technique has two main advantages: it allows the graft to follow the perimeter of the heart avoiding the possibility of kinking, and it maximizes the number of distal anastomoses.
The conduit should be carefully measured and marked at the anastomotic sites. It is helpful to have an assistant holding the conduit with the ventral side (fascia side for the internal thoracic artery) facing the surgeon and ensuring the conduit is not twisted. A bulldog clip is placed proximal to the incision when using an in in situ graft. The conduit is opened, with care taken to avoid large incisions, as this will cause flattening and kinking of the conduit and impede adequate flow. The coronary arteriotomy is then prepared, using the same technique described for latero-lateral anastomoses. The length of the coronary arteriotomy should be 20% smaller then graft arteriotomy to avoid flattening of the anastomosis ( Figs. 9.2 and 9.3 ).
To aid in the understanding of the steps involved in constructing this type of anastomosis, please refer to Fig. 9.4 . The anastomosis is started at the 3 o’clock position of the incision on the graft (ag in Fig. 9.4 ) using 7-0 or 8-0 prolene. The needle is first passed from the outside to the inside of the graft arteriotomy, then through the coronary artery from inside out at the exact middle point of the right side of the coronary arteriotomy (ac in the figure). The suture runs posteriorly toward the heel of the incision on the conduit until the middle point of the coronary arteriotomy (9 o’clock on the surgeon’s side) is reached. At this time the conduit is parachuted down and the loops tightened with a fine hook, ensuring there are equal lengths of suture at each end of the anastomosis. The rest of the anastomosis is continued forehand from 9 o’clock (cg in the figure) until 12 o’clock (dg in the figure) and backhand from 12 to 3 o’clock (ag in the figure). This technique ensures a Latin cross configuration keeping the conduit and coronary target arteriotomies always at 90 degrees angle.
