Introduction
There are two reasons to construct “baby Y grafts.”
- 1.
to allow distal graft to coronary anastomosis to be constructed in the best possible site in the coronary (vessel wall quality and size) when otherwise the lie of a potential sequential graft especially to the circumflex system would not be ideal and
- 2.
to use available conduit efficiently—either when there is a potential conduit shortage, or to minimize the number of incisions and conduit harvest sites.
The use of Y grafts in coronary surgery was popularized by Tector et al. and Sauvage, with the use of left internal thoracic artery (LITA)–right internal thoracic artery (RITA) Y grafts in the 1980s to achieve multi or total arterial revascularization . Subsequently, Calafiore and others promoted LITA Y grafts with the radial artery (RA) as the secondary conduit . From time to time, others have used LITA–saphenous vein (SVG) Y grafts either when there was conduit shortage or intentionally with the SVG used to revascularize the lateral posterior and inferior left ventricle (LV) myocardium .
Background
Although our practice had been predominantly to use individual conduits to each coronary branch that required grafting, we occasionally (15%) use sequential grafting to the circumflex system—initially with SVG (1970s), with the RITA (1980s), and with the RA (1995 and onwards). Not infrequently, we found that in attempting to obtain the best and most efficient “lie” for the sequential graft, we were compromised in having to choose anastomotic points in the coronaries that were often not ideal. In addition, occasionally, the stenosis and disease in a proximal/closer circumflex branch may have been further down and more extensive, thus necessitating grafting more distally, which then further compromised the most distal/furthest anastomosis in the sequential graft necessitating it to go to a second or third marginal quite distally where the vessel was almost always smaller.
On the right side, sequential grafting from a posterolateral (left ventricular) branch of the right coronary artery (RCA) distally (end to side) to a sequential anastomosis (side to side) to the posterior descending (PDA) often meant that the conduit was often not long enough to reach the aorta. Hence, a further strategy had to be adopted such as graft extension or inflow from the distal end of the RITA. An aortocoronary conduit to the PDA with an additional shorter conduit to the left ventricular branch or posterolateral, then proximally connected (end to side) to the primary conduit, often at the acute margin where such anastomosis was straight forward to construct was a solution to this problem.
“Baby Y” graft with the left internal thoracic artery as the primary conduit
When the left anterior descending (LAD) and major diagonal artery both have significant stenoses, and the diagonal is of a suitable size and runs in close proximity to the LAD, if the LITA is of sufficient quality, size, and flow, then most surgeons would construct a parallel sequential anastomosis to the diagonal and then the terminal (end to side) anastomosis to the LAD.
However, if the affected diagonal is very proximal (high first diagonal/intermediate/rhamus) or if the diagonal artery runs laterally, rather than parallel to the LAD, or if there is a lot of proximal disease, these situations mitigate against a sequential LITA diagonal LAD construction but are addressed by a LITA baby Y graft.
The side limb is usually a small segment of RA, or the distal end of a long skeletonized LITA. The side limb needs only to be 3–4 cm in length. Distally, it can be placed in the most suitable part of the diagonal or intermediate with a usual end to side distal anastomosis (7/0 or 8/0 polypropylene), and proximally end to side to the anterior, or left lateral wall of the LITA (7/0 polypropylene) ( Figs. 11.1–11.4 ).
Similar techniques have been described . The exact length of the side limb is not crucial, as the LITA pedicle has potentially freedom of lie in positioning, without distortion or tension. Both the LITA and the side limb are secured by small adventitial sutures to the epicardium, approximately 2 cm proximal to the distal anastomosis to ensure correct lie and prevent rotation and distortion at the distal anastomosis. “Tisseel” (Fibrin glue, Baxter, Westlake, CA, United States) or similar sealants can be used on the epicardium adjacent to the conduits to ensure the correct lie.
We would strongly advise against the use of an aortocoronary SVG graft to a laterally placed diagonal or intermediate artery (unless it was completely occluded proximally, and completely separated from the LAD) as the flow in the SVG in the early phases would overwhelm the ITA flow, and result in an LITA string sign and an ineffectual graft to the LAD.
“Baby Y” graft to the circumflex marginals
This is the commonest application of this technique. Ideally, a sequential grafting technique should be used if two or more circumflex marginal branches require revascularization. However, as mentioned, if the ideal lie of such a graft would result in compromise with respect to the site for distal anastomosis, then the “baby Y” technique allows the distal anastomoses to be constructed in the most ideal sites in the vessels to be bypassed, with respect to vessel wall quality, and size.
The most common conduit used is the radial, but the technique can also be applied to SVG or RITA. The easiest way to deploy this technique is to construct a routine RA aortocoronary bypass graft to the more proximal circumflex marginal that needs to be bypassed. Then a shorter (usually 5–6 cm length of RA, RITA, or SVG) is used to graft the more distal circumflex marginal in its most ideal location (end to side 7/0 polypropylene). The LV is then filled or alternatively an estimation of the LV size in diastole made, and an anastomotic site is chosen on the primary aortocoronary circumflex marginal graft. A 7–8 mm arteriotomy is created, and then a parallel end to side anastomosis constructed with continuous 7/0 polypropylene, ensuring a large “pouting” hood for the inflow anastomosis. The adventitia of the relevant conduits is loosely approximated to the epicardium with 6/0 polypropylene to ensure the grafts sit in the best possible position, with the main, primary graft almost universally running from the lateral heart over the left atrial appendage to the aorta ( Figs. 11.5–11.7 ).
