In recent years, coronary revascularization has been dominated by interventional cardiologists. Cardiac surgeons face new challenges as coronary revascularization becomes more complex. The definition of complexity is wide and includes many anatomical situations. In routine clinical practice, we commonly find small coronary vessels (≤1 mm), occluded (or nearly occluded) vessels on viable territories, and vessels with multiple sequential stenosis and multiple stents ( Video 25.1 ). Patients with these characteristics present many strategical and technical problems. In addition to this, there are patients who need repeated revascularization after numerous interventional procedures and in the presence of challenging anatomical considerations.
Coronary angiography. (A) Without contrast: the extensive calcifications and the impressive number of stents in all coronary territories can be seen. (B and C) The distal vessels are calcified and of small caliber. The video can be found on online at https://doi.org/10.1016/B978-0-12-820348-4.00025-X .
On- or off-pump?
While the decision to perform on- versus off-pump surgery is surgeon specific, it is our belief that at present, off-pump performance of complex coronary surgery requires some compromise in terms of quality of the surgical result. For instance, in cases of long endarterectomy or stent–endarterectomy, the incision needs to be shorter and this limits distal and proximal surgical reach. We recommend the performance of all complex coronary surgery procedures on-pump as technical perfection supersedes the hypothetical advantage of eliminating cardiopulmonary bypass.
Myocardial protection
In our opinion the antegrade and retrograde routes must be used as complementary methods to overcome problems that may arise during complex surgery. We typically prefer to use warm blood cardioplegia that provides good protection even with long cross-clamp times, particularly in patients with low ejection fraction. Retrograde cardioplegia may be particularly useful for protecting the myocardium and washing out debris when performing endarterectomies.
Endarterectomy/stent–endarterectomy or long anastomoses (onlay patching or separate patching)
Our armamentarium consists of patching a long incision with a separate patch [generally, a segment of a saphenous vein graft (SVG)] or with the conduit used for grafting (onlay patching with an internal mammary artery or a radial artery or an SVG):
- 1.
after open or closed endarterectomy (no lumen or excess of atheromatous tissue);
- 2.
after open or closed stent–endarterectomy (lack of anastomotic site or necessity to eliminate multiple stents with restenosis); and
- 3.
without material removal, if there is a lumen, even if minimal, and a reasonable quality of the target vessel.
Endarterectomy
First described in 1956 by Lillehei et al. , endarterectomy is an old procedure first successfully used in a human patient by Bailey et al. . As a general principle, the length of the incision correlates with the length of the material removed. It is important to remain distal to the most proximal area of stenosis and to be sure that the distal portion of the core tapers nicely while also ensuring there is no intimal folding. Once the core is extracted, care must be taken to avoid any occlusion of the coronary branches as much as possible. The remaining surface is then gently cleaned while securing the intima at the two edges with interrupted 8–0 sutures to prevent possible occlusion of the anastomosis or the vessel by an intimal flap. Alternatively, when performed on a beating heart, endarterectomy can be performed through a shorter incision, pulling out the core from both sides of the coronary artery. There is less control, but similar results can be obtained with this technique. Some surgeons use gentle external pushing on the closed segment of the coronary artery while using a peanut to facilitate plaque extraction (personal communication David Taggart). We generally favor the open method, as it provides more control while allowing for a careful inspection of the anatomic results. It is crucial to use retrograde cardioplegia to flush any debris and ensure myocardial protection.
- 1.
For the left anterior descending artery (LAD): it is preferable to use the left internal mammary artery (LIMA) as much as possible (onlay patching). If the length is excessive, an SVG patch may be used from the end of the LIMA to the end of the incision. Alternatively, an SVG patch may be used and the LIMA anastomosed to its proximal side ( Fig. 25.1 ). A patch with the right internal mammary artery (RIMA) is also possible if the conduit is not used for other targets.
Figure 25.1
Endarterectomy: (A) The LAD is nearly occluded. (B) Intraoperative view. The endoarterectomized segment has been closed with an SVG patch and the LIMA anastomosed over it. (C and D) CT coronary angiography after 58 months from surgery. Good patency of the endarterectomized LAD segment closed by an SVG patch with the LIMA anastomosed over it. CT , Computed tomography; LAD , left anterior descending artery; LIMA , left internal mammary artery; SVG , saphenous vein graft.
- 2.
For any other coronary artery : it is preferable to use an SVG patch to close the incision as onlay anastomosis. The SVG is more user-friendly and avoids any problem due to lack of material.
The stent–endarterectomy is a more recent evolution of endarterectomy. The concept is similar, but the difference is that there are one or more stents inside the core ( Fig. 25.2 ). The removal of the stents is not extremely difficult once there is a clear plan and may be even easier than in conventional endarterectomy. It is useful to know that the stents can be cut using Pott’s forceps.
Long anastomoses
In many cases the coronary arteries, and in particular, the LAD, present multiple stenoses ( Fig. 25.3 ). The optimal solution is to open the coronary as much as necessary to achieve an acceptable size ( Video 25.2 ). The incision may be closed with a LIMA (Video 25.3, Fig. 25.4 ) or an SVG onlay patch ( Video 25.3 , Fig. 25.4 ), or with an SVG as a patch ( Video 25.2 ). This technique may be preferred over endarterectomy when there is a lumen, even if small, and the plaque does not involve the full diameter of the vessel. In this case the patch needs to be sutured with the aim of eliminating the diseased tissue as much as possible.
LAD patching for multiple stenoses. A long incision is performed on the LAD to reach distally and proximally a portion of the vessel without calcifications and plaques. A long SVG patch is used to close the incision. The LIMA is anastomosed proximally to the patch. The video can be found on online at https://doi.org/10.1016/B978-0-12-820348-4.00025-X .
LAD and PDA patching for multiple calcified stenoses. Coronary angiography. Preoperatively (A–C), all the coronary vessels are diseased with multiple stenoses. (D and E) Postoperative control (10 days after surgery). A long onlay LIMA anastomosis (~5 cm) allows recovery of a reasonable part of the LAD territory. An SVG is anastomosed to the OM branch, with a long onlay anastomosis (~5 cm), to the PDA. The RIMA is proximally anastomosed to the SVG and distally to both small-sized diagonal branches. The video can be found on online at https://doi.org/10.1016/B978-0-12-820348-4.00025-X .
