Coronary Artery Bypass Grafting Technique

The goal of coronary artery bypass grafting (CABG) is complete revascularization of the area of the myocardium that is perfused by coronary arteries with a luminal stenosis of more than 50%. Several methods may be used for this purpose. A durable conduit is vital for successful CABG. There are a number of sites from which the conduit can be harvested, including the following:

• Saphenous vein

• Radial artery

• Left internal thoracic (mammary) artery (LITA)

• Right internal thoracic (mammary) artery (RITA)

• Right gastroepiploic artery

• Inferior epigastric artery

Saphenous vein

The great (long) saphenous vein (GSV) is located 2 cm anterior to the medial malleolus, traverses the tibia, and ascends posteriorly up the tibial border before emptying into the femoral vein. It receives numerous tributaries, notably at the knee, and contains 10-20 valves. Key associated structures are the saphenous nerve, femoral cutaneous nerve, and saphenous branch of the genicular artery. The small (short) saphenous vein (SSV) is located 1 cm posterior to the lateral malleolus, runs centrally up the posterior calf, and drains into the popliteal vein.

As coronary artery bypass grafting (CABG) conduits, the saphenous veins have an 80-90% early patency rate, which decreases to 50% at 10 years. The saphenous vein is generally acceptable as a conduit in the absence of other vascular pathologies in the leg (varicosities in the vein, venous insufficiency, previous deep vein thrombosis [DVT], or small lumen diameter) or overlying infection.

The GSV can be procured either via an open harvest technique (see the image below), starting from either the ankle or groin and using a vein stripper, or via an endoscopic technique. Likewise, the SSV vein can be harvested either with an open procedure or endoscopically.

Published experience comparing open vein harvest (OVH) with endoscopic vein harvest (EVH) suggests decreased wound-related complications, improved patient satisfaction, shorter hospital stay, and reduced postoperative pain at the harvest site following EVH. ^{[51, 52, 53]}  Vein trauma is minimized by constant visualization, proper countertraction, and careful hemostasis. The available evidence predominantly confirms that EVH is no worse than OVH at short- and mid-term follow-up. ^[54]

 

The legs and groin should be shaved, prepared, and draped in the operating room. Care should be taken to avoid getting skin preparation solution on the diathermy plate; this can result in diathermy burns. Once the anesthetist is ready for surgery to start and the surgeon has confirmed the number of lengths (25 cm) of vein required, the vein harvest can begin.

Internal thoracic (mammary) artery

The left internal thoracic (mammary) artery (LITA) and the right internal thoracic (mammary) artery (RITA) arise from their respective subclavian arteries. The internal thoracic (mammary) artery can be harvested either by itself or as a pedicle (see the figure below).

 

Whereas the LITA is most commonly harvested as a pedicle, the RITA is generally skeletonized, because an RITA pedicle may interfere with sternal wound healing. The LITA is useful in left anterior descending (LAD) artery anastomosis and has a good patency rate in this setting (98% at 1 year and 90% at 10 years). The RITA has a good patency rate when anastomosed to the LAD (96% at 1 year and 90% at 5 years) but a reduced rate when grafted to the circumflex or the right coronary artery (75% at 1 year).

The usual incision for coronary artery bypass grafting (CABG) is a midline sternotomy (see the image below), although an anterior thoracotomy for bypass of the left anterior descending (LAD) artery or a lateral thoracotomy for marginal vessels may be used when an off-pump procedure is being performed.

 

CABG with cardiopulmonary bypass and cardioplegic arrest is demonstrated in the video below.

Cardiopulmonary bypass

The first step in cardiopulmonary bypass is to cannulate the aorta and right atrium. The aortic area selected for cannulation must be soft and nonatherosclerotic. To insert the aortic cannula, unfractionated heparin is given, and the systolic blood pressure is lowered to below 100 mm Hg. At this point, two purse-string sutures are placed into the aorta, and the aortic adventitia within the diameter of the purse-string sutures is divided. An aortotomy is performed with a scalpel, the cannula is placed, and the purse-string sutures are tightened around it.

The aortic cannula is then secured to a rubber tourniquet with a heavy silk tie. Once in place, the cannula is de-aired and connected to the arterial pump tubing, where its position in the aorta can be confirmed by watching the pattern of tube filling. The venous cannula is inserted into the right atrial appendage in a similar fashion, with the end of the cannula positioned in the inferior vena cava. Adequate anticoagulation is confirmed by assessing the activated clotting time; once this is done, cardiopulmonary bypass can be commenced.

The aorta is cross-clamped distal to the cannula, and cold cardioplegia solution is infused via the aortic cannula (some centers also cool the patient). Retrograde cardioplegia may also be administered via the coronary sinus, especially in the patient who is undergoing repeat CABGs and has few or no patent grafts for adequate perfusion with antegrade cardioplegia. Compared with crystalloid cardioplegia, blood cardioplegia is associated with a lower incidence of intraoperative mortality, postoperative myocardial infarction, shock, and conduction defects.

Placement of graft

After the initiation of cardiopulmonary bypass, the distal coronary bypass targets are identified. As a rule, anastomoses to the right coronary artery and the marginal branches of the circumflex artery are completed first.

The circumflex argery is accessed by retracting the heart laterally, whereas the posterior descending artery and posterolateral circulation are accessed by retracting the heart cephalically. The left internal thoracic (mammary) artery (LITA) is then usually anastomosed to the LAD if possible. In rare circumstances (eg, CABG performed for acute anterior myocardial infarction), a saphenous vein graft may be placed to the LAD artery for expediency.

To accomplish the bypass, an incision is made in the distal coronary artery, and the conduit ostium is sutured around the full circumference of the anastomosis (see the image below). The conduit is then infused with cold cardioplegia solution, and the end is tied with a polypropylene suture. A very fine monofilament suture, commonly 7-0 or 8-0, is used to complete the distal coronary anastomosis. Most often, it is an end-to-side anastomosis as shown in the picture below. Often, we can construct a side-to-side anastomosis when a sequential anastomosis was performed with the same conduit.

 

When all the distal anastomoses are completed, rewarming of the heart is initiated, the aortic cross-clamp is removed, and a partially occluding clamp is placed on the ascending aorta where the grafts are to be anastomosed. Holes are punched in the ascending aorta, secured by the partially occluded clamp, and the proximal ends of the anastomoses are sutured into place in the aorta (see the image below). Before the cross-clamp is finally removed, air is evacuated from the grafts and ascending aorta. The patient is then weaned off the bypass.

 

When normal rhythm is resumed, the patient is once again mechanically ventilated and electrolyte abnormalities (commonly hypomagnesemia and hypokalemia) are corrected. If the patient is bradycardic or experiences temporary heart block, temporary pacing is performed using wires placed to the right atrium and right ventricle. When cardiopulmonary bypass has been successfully stopped, protamine is given to reverse the heparin. ^[55]

Off-pump CABG

The key to off-pump coronary artery bypass grafting (OPCABG) is the maintenance of blood pressure, heart rate, and normothermia (with the use of warming blankets). Preload must be optimized during manipulation of the heart to minimize hemodynamic instability. A number of techniques can be used to prevent hypotension, including prophylactic intravenous (IV) fluid infusion, use of the Trendelenburg and reverse Trendelenburg positions, and low-dose alpha-agonist infusion. ^[56]

A systematic review did not demonstrate any significant benefit of (OPCABG) compared with on-pump CABG (ONCABG) regarding mortality, stroke, or myocardial infarction. ^[57]

Totally endoscopic CABG

Endoscopic surgical techniques with robotic assistance were developed to enable the performance of surgery in difficult spaces; they are widely used across most surgical disciplines. The specific application of these techniques to the treatment of coronary artery disease (CAD) is known as totally endoscopic CABG. Totally endoscopic CABG, which aims to decrease postoperative morbidity, duration of hospital stay, and overall cost, allows surgeons to perform endoscopic surgery on both the beating and arrested heart. ^[58]

The first step in totally endoscopic CABG is to deflate the lung. Next, three small incisions are made at the intercostal spaces, through which one robotic arm with an attached endoscope and two arms carrying surgical accessories are passed. These arms are controlled by the operator from a unit located away from the operating table. Grafts are then harvested from suitable sites, and an anastomosis is completed across the affected coronary artery. ^[59]

Hybrid technique

Advances in surgical techniques and introduction of drug-eluting stents have provided a platform for a hybrid combined strategy that involves grafting the left anterior descending artery with the left internal thoracic (mammary) artery and then stenting the other coronary territories with drug-eluting stents instead of bypassing them with saphenous vein grafts.

Although preliminary data indicate that such a hybrid strategy may be a reasonable alternative for some patients with multivessel coronary artery disease, the real clinical utility of this approach will not be known until results of randomized clinical trials are available.

A number of complications are associated with coronary artery bypass grafting (CABG), both in the short term and in the long term; they are associated with anesthesia, cardiopulmonary bypass, sternotomy, and the operation itself. These complications may include the following:

• Myocardial dysfunction

• Cerebrovascular complications

• Acute renal failure

• Cardiac tamponade

• Respiratory tract infections

• Aortic dissection

In the initial postoperative period, there is a decline in myocardial function secondary to myocardial edema and ischemia-reperfusion injury. Additional factors (eg, incomplete revascularization and postoperative graft failure) may exacerbate the dysfunction. Patients may exhibit a low-output syndrome, with 4-9% requiring the use of inotropes or intra-aortic balloon pulsation. Additionally, segmental transmural myocardial infarction occurs in 1-5% of patients, and postoperative arrhythmias occur in approximately 30% of patients after CABG. ^[60]

Adverse neurologic outcomes are a major concern in cardiac surgery, with 3.1% for major (type I) events (eg, major neurologic deficits and coma) occurring in 3.1% of cases, and 3% for less-debilitating (type II) events (deterioration of intellectual function or memory). Both types of events result in a significant increase in mortality: 21% for type I events and 10% for type II. ^[61] Despite the increased mortality associated with type II events, the majority of survivors return to normal activity in the following 3-12 months. ^[62]

Postoperative renal failure is a significant cause of mortality after CABG. There is a 4% incidence of renal failure; 20% of these patients require dialysis, and the mortality is 50%.

Issuing Organizations and Classifications

Clinical guidelines on myocardial revascularization have been issued by the following organizations:

• American College of Cardiology (ACC)/American Heart Association (AHA)
• European Society of Cardiology (ESC)/European Association for Cardio-Thoracic Surgery (EACTS)
• Society of Thoracic Surgeons
• ACC/AHA/Society for Cardiovascular Angiography and Interventions (SCAI)

Recommendations have been classified in both ACC/AHA and ESC/EACTS guidelines according to the level of evidence supporting the usefulness and efficacy of the procedure ^{[2, 63]} :

• Class I - Conditions for which there is evidence and/or general agreement that a given procedure or treatment is useful and effective
• Class II - Conditions for which there is conflicting evidence and/or a divergence of opinion about the usefulness or efficacy of a procedure or treatment
• Class IIa - Weight of evidence or opinion is in favor of usefulness or efficacy
• Class IIb - Usefulness or efficacy is less well established by evidence or opinion
• Class III - Conditions for which there is evidence and/or general agreement that the procedure/treatment is not useful or effective, and in some cases may be harmful

Treatment Strategy Selection

The ACC/AHA, ^[2] ESC/EACTS, ^[63] and ACC/AHA/SCAI ^[1] guidelines give a class I recommendation to the use of a Heart Team approach in determining treatment strategy and selection of appropriate revascularization procedure (ie, percutaneous coronary intervention [PCI] or coronary artery bypass grafting [CABG]). The ACC/AHA guidelines define a Heart Team as “a multidisciplinary team composed of an interventional cardiologist and a cardiac surgeon who jointly 1) review the patient’s medical condition and coronary anatomy, 2) determine that PCI and/or CABG are technically feasible and reasonable, and, 3) discusses revascularization options with the patient before a treatment strategy is selected.” ^[2]

This approach is similar to the tumor board or “supreme court” approach to complex or high-risk cases, or where there are not enough data (gray areas). For instance, use in patients with unprotected left main or complex coronary artery disease (CAD) is recommended. ^[2] .

On the other hand, the 2014 ESC/EACTS guidelines revised its recommendation from previous guidelines to include the development and use of standardized, evidence-based, and interdisciplinary protocols for low-risk and common scenarios; however, in such cases, revascularization at the time of diagnostic angiography is recommended against in order to allow for full assessment of the optimal treatment strategy. Multidisciplinary systematic evaluation is still required for complex cases. ^[63]

The Society of Thoracic Surgeons (STS) and SYNTAX (Synergy between Percutaneous Coronary Intervention with TAXUS and Cardiac Surgery) scores are recommended by both ACC/AHA and ESC/EACTS guidelines for risk stratification to aid in clinical decision-making. ^{[2, 63]}

Emergency CABG

Both ACC/AHA and ESC/EACTS provide guidance on the use of CABG as an emergency procedure. ^{[2, 63]}

ACC/AHA guidelines provide a class I recommendation for CABG in the context of an ST-segment elevation myocardial infarction (STEMI) in cases where PCI has been impossible to perform or has failed and the patient has persistent pain and ischemia threatening a significant area of myocardium despite medical therapy. ^[2]  In the 2021 updated guidelines, this recommendation has been downgraded to class IIa. ^[1]

Other class I indications for emergency open heart surgery in the setting of STEMI include the following:

• Ventricular pseudoaneurysm
• Life-threatening ventricular arrhythmias
• Cardiogenic shock: In patients with STEMI and cardiogenic shock or hemodynamic instability, PCI or CABG (when PCI is not feasible) is indicated for improving survival, irrespective of the time delay from MI onset. ^[1]
• Mechanical complications such as ventricular septal defect, mitral valve insufficiency due to papillary muscle infarction or rupture, or free wall rupture: CABG is recommended at the time of surgery to improve survival. ^[1]

Emergency CABG is not recommended in the following cases ^[2] :

• Persistent angina but only a small area of ischemia AND hemodynamically stable
• No-reflow state (successful epicardial reperfusion with unsuccessful microvascular reperfusion)
• Ventricular tachycardia with scar and no evidence of ischemia

CABG after failed PCI

Recommendations for emergency CABG after failed PCI include the following ^[2] :

• Ongoing ischemia or threatened occlusion with myocardium at risk (class I)
• Hemodynamic compromise without impairment of coagulation and without a previous sternotomy (class I)
• Hemodynamic compromise with impairment of coagulation and without a previous sternotomy (class IIa)
• Hemodynamic compromise and previous sternotomy; emergency CABG may be considered (class IIb)
• Retrieval of a foreign body (eg, fractured guidewire or stent) in a crucial location (class IIa)

The updated 2021 ACC/AHA/SCAI guidelines note that emergency CABG is reasonable in individuals with non-ST elevation-acute coronary syndrome (NSTE-ACS) in whom PCI has failed and who have ongoing ischemia, hemodynamic compromise, or threatened arterial occlusion with substantial myocardium at risk, and who are appropriate candidates for CABG. ^[1]

Emergency CABG should not be performed after failed PCI in the absence of ischemia or threatened occlusion, or if revascularization is impossible or futile because of target anatomy or a no-reflow state. ^{[1, 2]}

Indications and Contraindications

For decisions and recommendations on revascularization, the ACC/AHA guidelines, released in 2011, define significant stenosis as ≥70% diameter narrowing (≥50% for left main CAD). Physiological criteria, such as fractional flow reserve ≤0.80, may also be considered significant. In addition, some recommendations use SYNTAX scores as surrogates for the extent and complexity of CAD. ^[2]

CABG may be performed to improve symptoms and/or improve survival, with the latter generally given greater weight when selecting a procedure. The guidelines note that in discussions of options, the patient should clearly understand the goal of the procedure (symptom relief, improved survival, or both) before a decision is made. ^[2]

CABG for symptom improvement

Recommendations for CABG for symptom improvement are as follows ^{[2, 63]} :

• Significant stenosis and unacceptable angina despite medical therapy (class I recommendation for both ACC/AHA and ESC/EACTS)
• Significant stenosis and unacceptable angina in patients with medication contraindications or adverse effects, or patient preference (ACC/AHA class IIa)
• In a good candidate, CABG may be considered over PCI for complex three-vessel CAD (eg, STYNTAX score >22) with or without involvement of the proximal LAD artery (ACC/AHA class IIa but ESC/EACTS class I)
• Transmyocardial laser revascularization (TLR) as an adjunct to CABG may be considered in patients with viable ischemic myocardium that is perfused by coronary arteries that are not amenable to grafting (ACC/AHA class IIb)

CABG for survival improvement

ACC/AHA and ESC/EACTS recommendations for CABG to improve survival are compared in Table 13, below. ^{[2, 63]}

Table 13. Indications for Coronary Artery Bypass Grafting (Open Table in a new window)

In the updated ACC/AHAI/SCAI guidelines, elective CABG is reasonable after successful primary PCI in selected patients with STEMI with complex multivessel noninfarct artery disease (class IIa). ^[1]  For those who require revascularization for significant left main CAD with high-complexity CAD, CABG is recommended over PCI for survival improvement (class I). It is reasonable to choose CABG over PCI to confer survival advantage in patients who require revascularization for multivessel CAD with complex or diffuse CAD (eg, SYNTAX score >33). ^[1]

For recommendations on management of stable ischemic heart disease, see Table 14, below.

 Table 14. Updated ACC/AHA/SCAI Recommendations for Revascularization for Survival Improvement in Stable Ischemic Heart Disease Versus Medical Therapy ^[1] (Open Table in a new window)

Class IIa recommendations state revascularization is reasonable to reduce the risk of cardiovascular events (eg, spontaneous MI, unplanned urgent revascularizations, cardiac death) in those with stable ischemic heart disease and multivessel CAD that is appropriate for either CABG or PCI. ^[1]

Neither CABG nor PCI should be performed in those with angina but no anatomic or physiologic criteria for revascularization. ^[1]

Previous CABG

It is reasonable to choose CABG over PCI in patients with previous CABG in the following settings ^[1] :

• Refractory angina on medical therapy that is attributable to left anterior descending (LAD) artery disease when an internal mammary artery (IMA) can be used as a conduit to the LAD (class IIa)
• Complex CAD when an IMA can be used as a conduit to the LAD (class IIb)

It is reasonable to select PCI over CABG in those with a previous CABG and a patent left IMA (LIMA) to the LAD artery who need revascularization, providing PCI is feasible (class IIa). ^[1]

CABG is reasonable over PCI in patients with multivessel CAD that is amenable to treatment with either PCI or CABG who are unable to access, tolerate, or adhere to dual antiplatelet therapy. ^[1]

Comorbidities/Higher-Risk Cohorts

Diabetes mellitus

The ACC/AHA recommends CABG over PCI for improved survival in patients with comorbid diabetes mellitus (DM) and multivessel CAD, particularly with use of the LIMA; the recommendation was upgraded from class IIa in the 2011 guidelines to class I in the 2014 guidelines and remains class I in the 2021 updated guidelines.[ref76} However, the use of bilateral internal mammary arteries is associated with increased risk of infection and should be considered only when the benefit outweighs the increased risk (class IIb). ^[2]  In diabetic persons with left main stenosis and low- or intermediate-complexity CAD in the rest of their coronary anatomy, PCI may be considered an alternative to CABG to reduce major adverse cardiovascular outcomes. ^[1]

In a 2014 update of the guidelines for patients with stable ischemic heart disease (IHD), the American College of Cardiology (ACC)/American Heart Association (AHA)/American Association for Thoracic Surgery (AATS)/Preventive Cardiovascular Nurses Association (PCNA)/Society for Cardiovascular Angiography and Intervention (SCAI)/Society of Thoracic Surgeons (STS) provided the following recommendations for patients with stable IHD and DM ^[64] :

• Patients should receive medical therapy
• Revascularization should be considered for patients with symptoms that remain inadequately controlled despite medical therapy
• A Heart Team approach is beneficial in the evaluation of CABG versus PCI; mortality risk appears to be lower with CABG than with PCI in most patients with DM and complex multivessel disease, but exceptions may be identified

The ESC/EACTS guidelines recommend CABG as the revascularization modality of choice for improved survival in patients with DM and multivessel or complex (SYNTAX Score >22) CAD. However, PCI can be considered as a treatment alternative in diabetic patients with multivessel disease and a low SYNTAX score (≤22). ^[63]

Kidney disease

In the setting of end-stage renal disease, the ACC/AHA consider CABG as reasonable (class IIb recommendations) for the following indications ^[2] :

• To improve survival for patients with left main coronary artery stenosis ≥50%
• To improve survival and relieve symptoms resistant to medical therapy in patients with ≥70% stenosis in three major vessels or in the proximal LAD artery plus one other major vessel

CABG should not be performed in patients with end-stage renal disease whose life expectancy is limited because of noncardiac conditions. ^[2]

The ESC/EACTS guidelines prefer CABG over PCI for patients with multivessel CAD and chronic kidney disease (CKD) when surgical risk is acceptable and life expectancy is longer than 1 year; PCI is preferred for those patients with high surgical risk and/or life expectancy of less than 1 year but may be challenging in those with heavily calcified coronaries. Considerations include delaying CABG until the effects of angiography on renal function have subsided. ^[63]

Valvular disease

The ACC/AHA recommendations for patients with valvular disease are as follows ^[2] :

• Aortic valve replacement for patients with moderate or worse aortic stenosis undergoing CABG (class I)
• Patients with ischemic mitral valve regurgitation that is not likely to be resolved with revascularization should have concurrent mitral valve repair or replacement while undergoing CABG (class I recommendation for severe regurgitation, class IIa for moderate regurgitation, class IIb for mild regurgitation)
• In patients undergoing concurrent valvular surgery, intraoperative transesophageal echocardiography should be performed (class I)

The ESC/EATS recommendations include the following ^[63] :

• Perform CABG in patients with stenosis >70% in a major vessel and an aortic/mitral valve surgery indication (class I)
• Consider CABG in patients with stenosis 50-70% in a major vessel and an aortic/mitral valve surgery indication (class IIa)
• Perform mitral valve surgery in patients with severe mitral regurgitation and LVEF >30% who are undergoing CABG (class I)
• Consider mitral valve surgery in patients with moderate mitral regurgitation who are undergoing CABG (class IIa)
• Consider repair of moderate-to-severe mitral regurgitation in patients undergoing CABG who have LVEF≤35% (class IIa)
• Consider aortic valve surgery in patients with moderate aortic stenosis who are undergoing CABG (class IIa)

Carotid/peripheral artery disease

The ACC/AHA guidelines provide the following recommendations for patients with comorbid carotid artery disease ^[2] :

• Patients with significant carotid artery disease require a multidisciplinary team (cardiologist, cardiac surgeon, vascular surgeon, and neurologist) approach (class I)
• Patients with high-risk features (ie, age >65 years, left main artery stenosis, PAD, hypertension, smoking, diabetes mellitus, history of stroke or transient ischemic attack [TIA]) should undergo carotid artery duplex screening (class IIa)
• Carotid revascularization may be considered in CABG patients with previous TIA or stroke and significant (50-99%) carotid artery stenosis
• Timing of carotid intervention (synchronous or staged) should be based on relative magnitude of cerebral and myocardial dysfunction or jeopardy (class IIa)
• Carotid revascularization may be considered in patients with no history of TIA or stroke but severe bilateral (70-90%) carotid stenosis or unilateral severe carotid stenosis with contralateral occlusion (class IIb)

The ESC/EACTS guidelines for carotid artery revascularization in CABG patients include the following ^[63] :

• Carotid endarterectomy (CEA) or carotid artery stenting (CAS) should be performed only by teams with demonstrated 30-day combined death-stroke rates of < 3% in patients without previous neurologic symptoms and < 6% in patients with previous neurologic symptoms (class I)
• Indications for carotid revascularization should be individualized after discussion by a multidisciplinary team, including a neurologist (class I)
• Timing of procedures (synchronous versus staged) should be dictated by local expertise and clinical presentation, with the most symptomatic territory targeted first (class IIa)
• In patients with a history of TIA/stroke, carotid revascularization is recommended for 70-99% carotid stenosis in both men and women (class I) and may be considered for 50-69% carotid stenosis, depending on patient-specific factors and clinical presentation (class IIb)
• In patients with no history of TIA/stroke, carotid revascularization may be considered in men with bilateral 70-99% carotid stenosis, 70-99% carotid stenosis and contralateral occlusion, or 70-99% carotid stenosis and ipsilateral previous silent cerebral infarction (class IIb)
• Choice of carotid revascularization modality (CEA vs CAS) in patients undergoing CABG should be based on patient comorbidities, supra-aortic vessel anatomy, urgency of CABG, and local expertise (class IIa)
• Acetylsalicylic acid (ASA) immediately before and after carotid revascularization (class I)
• Dual antiplatelet therapy with ASA and clopidogrel for at least 1 month in patients undergoing CAS (class I)

The ESC/EACTS advise that CAS should be considered in patients with any of the following (class IIa):

• Post-radiation or post-surgical stenosis
• Obesity
• Hostile neck
• Tracheostomy
• Palsy
• Stenosis at different carotid levels or upper internal carotid artery stenosis
• Severe comorbidities contraindicating CEA

CABG Conduit Selection

The ACC/AHA guidelines make the following recommendations for bypass graft conduit selection ^[2] :

• Left internal mammary artery (LIMA) to bypass left anterior descending (LAD) artery (class I)
• Right internal mammary artery when LIMA is unavailable or unsuitable as a bypass conduit (class IIa)
• When anatomically and clinically suitable, use of a second internal mammary artery to graft the left circumflex or right coronary artery is reasonable to improve survival and decrease likelihood of reintervention (class IIa). This is weighed against the slightly increased risk of deep sternal wound infections in diabetics or the morbidly obese.
• In patients ≤60 years old with few or no comorbidities, complete arterial revascularization may be considered (class IIb)
• Arterial grafting of the right coronary artery when ≥90% stenosis (class IIb)
• Radial artery graft when grafting left-sided arteries with severe stenosis (>70%) and right-sided arteries with critical stenosis (≥90%) that perfuse LV myocardium (class IIb)

Guidelines on conduit selection from by the Society of Thoracic Surgeons include the following recommendations:

• Internal thoracic arteries (ITAs) should be used to bypass the LAD artery when bypass of the LAD is indicated
• As an adjunct to left internal thoracic artery (LITA), a second arterial graft (right ITA or radial artery) should be considered in appropriate patients
• Use of bilateral ITAs (BITAs) should be considered in patients who do not have an excessive risk of sternal complications
• To reduce the risk of sternal infection with BITA, skeletonized grafts should be considered, smoking cessation is recommended, glycemic control should be considered, and enhanced sternal stabilization may be considered
• As an adjunct to LITA to LAD (or in patients with inadequate LITA grafts), use of a radial artery graft is reasonable when grafting coronary targets with severe stenoses
• When radial artery grafts are used, it is reasonable to use pharmacologic agents to reduce acute intraoperative and perioperative spasm
• The right gastroepiploic artery may be considered in patients with poor conduit options or as an adjunct to more complete arterial revascularization
• Use of arterial grafts (specific targets, number, and type) should be a part of the discussion of the heart team in determining the optimal approach for each patient

Antiplatelet Therapy

Recommendations for the management of antiplatelet therapy in patients undergoing CABG have been provided by the following organizations:

• American College of Cardiology (ACC)/American Heart Association (AHA) – For patients undergoing CABG ^[2] or those with unstable angina/non–ST-elevation myocardial infarction (NSTEMI) ^[65] or non–ST-elevation acute coronary syndromes ^[66]
• European Society of Cardiology (ESC) – For patients undergoing CABG ^[67]

For preoperative management of antiplatelet therapy, see Table 15, below. ^{[2, 65, 66, 67, 68]}

Table 15. Preoperative management of antiplatelet therapy in patients undergoing CABG (Open Table in a new window)

For postoperative management of antiplatelet therapy, see Table 16, below. ^{[2, 65, 66, 67, 68]}

Table 16. Postoperative management of antiplatelet therapy in patients undergoing CABG (Open Table in a new window)