Proper surgical planning begins with a comprehensive preoperative evaluation based on the patient’s risk factors and anatomical characteristics. Extensive atheromatous disease in the ascending aorta can necessitate a crucial shift in strategy regarding the use of cardiopulmonary bypass (CPB), aortic clamping, cardioplegia, graft selection, and the feasibility of performing proximal anastomoses on the ascending aorta.

Managing a porcelain aorta can be challenging in many cases and may increase the risk of perioperative stroke (POS). To achieve optimal patient outcomes and reduce the risk of POS, the following section outlines several tips and tools that can prove highly useful in daily clinical practice.

Evaluation of the ascending aorta

The presence of arteriosclerosis in the ascending aorta is a well-established, independent risk factor for POS. These strokes may present as paucisymptomatic or “silent” events and are associated with cognitive decline following surgery. In patients with risk factors such as advanced age, heavy smoking, diabetes mellitus, or chronic kidney disease, preoperative aortic screening via computed tomography (CT) should be performed.

Intraoperative epiaortic ultrasound, although not available in all centers, is the most reliable diagnostic tool for assessing parietal calcifications. It helps avoid high-risk areas and identifies favorable points for cannulation, aortic clamping, and proximal anastomoses. Manual palpation, although widely used, can be subjective and unreliable, posing a risk of dislodging intraluminal atheromatous plaques in severely diseased aortas. Furthermore, palpation fails to detect soft atheroma or lipid-rich plaques with high embolic potential. Therefore, in addition to avoiding calcified regions, it is recommended to refrain from manipulating aortic areas with a wall thickness exceeding 1.5 mm during the aforementioned maneuvers. This pathological thickening correlates with atherosclerosis and embolic risk, even in the absence of calcification.

Use of cardiopulmonary bypass and graft selection

The no-touch approach, which avoids aortic manipulation, is advisable. Regarding CPB, various options are available: peripheral cannulation with CPB support or an off-pump strategy. CPB may or may not involve aortic clamping and cardioplegia compared to performing surgery on a beating heart. Notably, aortic clamping is the maneuver associated with the greatest degree of aortic manipulation and, consequently, the highest risk of embolism. In cases where safe clamping is not feasible, off-pump surgery with CPB support can be an alternative, particularly if preferred over a purely off-pump approach (ventricular dysfunction, hemodynamic instability, cerebrovascular disease, complex anatomy, lack of experience, etc.).

Regarding graft selection, in-situ arterial grafts using one or two internal thoracic arteries have become standard practice. Alternatively, the “T” or “Y” configuration of both mammary arteries is widely supported by robust scientific evidence. Although the use of the right gastroepiploic artery is far less standardized, it can be a valuable option, particularly in redo CABG procedures when mammary grafts are unavailable.

While the bilateral use of internal thoracic arteries is undoubtedly a valid solution, it is not a universal approach. This strategy can increase sternal complications and lead to underutilization of other free grafts, such as the saphenous vein or radial artery, both of which yield excellent results. Therefore, a broader and more individualized approach is necessary, considering different revascularization strategies based on anatomical characteristics.

Proximal anastomoses on the aorta or great vessels

Generally, conventional side-clamping should be avoided, as it exponentially increases the risk of POS due to hypotension, hypoperfusion, or embolism from plaque rupture associated with extensive aortic manipulation. Additionally, intimal rupture or aortic dissection is possible in severely diseased aortas. If aortic clamping is required, a single cross-clamp maneuver with proximal anastomoses performed during cardioplegia is preferable.

In cases involving CPB without aortic clamping, proximal anastomoses can be completed using commercial devices that create a “transmural airtight seal” in the aortic wall. These devices include HEARTSTRING® (single-use, less hemostatic, minimal aortic manipulation), ENCLOSE II® (reusable, more hemostatic, requires greater parietal and endoluminal manipulation), and VIOLA® (reusable, intermediate manipulation, limited experience). Another alternative is the same approach as off-pump surgery, constructing various composite graft configurations using in-situ mammary arteries while adhering to scientifically supported strategies.

The “piggyback” technique, wherein a proximal anastomosis is performed onto the dorsum of an existing bypass graft, can be considered. This technique involves a single aorta-to-graft anastomosis, with subsequent graft-to-graft connections.

Extra-anatomical proximal anastomoses are uncommon, with limited experience and long-term patency data. These configurations often result in longer graft paths with a higher risk of kinking. Theoretical options include the axillary, subclavian, carotid, brachiocephalic trunk, or right gastroepiploic artery.

Flow assessment and graft marking

Systematic transit time flow (TTF) measurements of grafts are recommended, along with thorough evaluation of graft configuration (appropriate angulation) and length adjustment throughout the conduit’s course. It is preferable to have a slightly longer graft than a tensioned bypass, which can lead to complications that are difficult to correct. Venous grafts undergo arterialization, and arterial grafts adapt to the higher flow demands of the coronary circulation, leading to some dilation and subsequent shortening over time.

Marking grafts, particularly proximally with surgical clips or silicone rings, has not shown long-term benefits or facilitation of future catheterization or transcatheter aortic valve implantation (TAVI).

When performing pericardial closure, it is advisable to do so over the grafts to protect them during potential reoperations and facilitate their identification by creating a dissection plane. The application of adhesion barriers such as CoSeal® can prevent pericardial adhesions and serve as a safeguard in future reoperations, where coronary grafts often complicate surgical exposure.

COMMENTARY:

POS is one of the most dreaded complications for surgeons, as it results in a dramatic increase in morbidity, mortality, and hospital costs in cardiac surgery.

In CABG, unless in-situ arterial grafts and an off-pump approach are employed, manipulation of the ascending aorta is usually necessary for clamping, aortic cannulation, and/or proximal anastomoses.

With the advancements in interventional cardiology and increasing life expectancy, patients undergoing CABG surgery have become increasingly complex. Among other factors, extensive arteriosclerosis of the ascending aorta is becoming more frequent, representing a substantial increase in POS risk during CABG procedures. This issue is of particular concern as it is the primary disadvantage compared to percutaneous coronary interventions.

For this reason, a thorough preoperative assessment with CT in patients with risk factors to evaluate the presence of porcelain aorta and the patency of potential internal thoracic artery grafts will facilitate a more precise and safer surgical strategy.

Moreover, familiarity with the various alternatives and devices designed for this purpose provides surgeons with a valuable array of options. Mastering these tools allows us to pursue our ultimate goal: ensuring our patients live longer and with better quality of life.

REFERENCE:

Sirin G. Surgical strategies for severely atherosclerotic (porcelain) aorta during coronary artery bypass grafting. World J Cardiol. 2021 Aug 26;13(8):309-324. doi: 10.4330/wjc.v13.i8.309.