What Imaging Is Best for Pre-Coronary Surgery Planning in Adults?

A 68-year-old male with multi-vessel coronary artery disease, confirmed by cardiac catheterization, is scheduled for coronary artery bypass grafting (CABG). He has no history of prior heart or chest surgery. As the cardiothoracic surgery team reviews his case, they need to finalize the operative plan, which requires a detailed assessment of cardiac structures beyond the coronary arteries themselves. What is the most appropriate imaging modality to evaluate for concurrent valvular disease, assess ventricular function, and identify potential sources of perioperative stroke?

This clinical workflow article addresses this specific scenario, providing a step-by-step guide based on the American College of Radiology (ACR) Appropriateness Criteria. For an adult patient with no prior cardiothoracic surgery undergoing preprocedure planning for coronary surgery, US echocardiography transesophageal is rated Usually Appropriate, offering critical information with no ionizing radiation.

Who Fits This Pre-Coronary Surgery Imaging Scenario?

This guidance applies to a well-defined patient population: adults who have a definitive diagnosis of coronary artery disease requiring surgical revascularization (e.g., CABG) and who have no history of prior cardiothoracic surgery. The primary purpose of the imaging is for preoperative planning, not for the initial diagnosis of coronary disease, which is typically established by invasive coronary arteriography.

This workflow is specifically for patients undergoing their first major chest or heart operation. The presence of postoperative changes, such as scar tissue, adhesions, and altered anatomy from a previous sternotomy, significantly changes the imaging approach and risk profile.

Key exclusion criteria—presentations that require a different imaging pathway—include:

• Patients with a history of cardiothoracic surgery: These patients fall under a separate ACR variant due to altered anatomy and the need to assess graft patency and safe re-entry.
• Patients undergoing noncoronary cardiac surgery: An individual scheduled for an isolated valve replacement or congenital heart defect repair without a planned CABG follows a different set of recommendations.
• Patients scheduled for non-cardiac thoracic surgery: Procedures like lung resection or esophageal surgery have distinct preoperative imaging requirements focused on thoracic, not primarily cardiac, anatomy.

What Anatomic and Functional Details Are You Assessing Preoperatively?

In a patient already slated for CABG, preoperative imaging is not about re-diagnosing coronary blockages. Instead, it aims to identify concurrent conditions that could alter the surgical plan, increase operative risk, or necessitate a combined procedure. The key questions are clinical, not just anatomical.

Valvular Heart Disease: A primary goal is to assess for hemodynamically significant valvular pathology. Moderate-to-severe aortic stenosis or mitral regurgitation is relatively common in this patient population. Identifying this preoperatively allows the team to plan for a combined CABG and valve repair or replacement, avoiding the need for a second, higher-risk operation in the future.

Aortic Atherosclerosis: The ascending aorta and aortic arch are evaluated for the presence of severe or mobile atheroma. This is a critical step in stroke risk stratification. If significant plaque is identified, the surgeon may alter the aortic cannulation site, the cross-clamping strategy, or even opt for an “off-pump” technique to minimize the risk of dislodging embolic debris during the procedure.

Left Ventricular Function: A precise assessment of global and regional left ventricular function, including the ejection fraction, provides a crucial baseline. It helps risk-stratify the patient for postoperative heart failure and guides perioperative management, including the use of inotropic support.

Other Structural Abnormalities: Less common but highly consequential findings include intracardiac masses, thrombi (especially in the left atrial appendage), or shunts like a patent foramen ovale (PFO). Discovering these conditions preoperatively is essential for preventing paradoxical embolism and other complications.

Why Is Transesophageal Echocardiography a Recommended Study for Pre-CABG Planning?

The ACR rates both US echocardiography transesophageal (TEE) and US echocardiography transthoracic (TTE) as Usually Appropriate for this scenario. Often, a TTE is performed first as a non-invasive baseline, with TEE reserved for when more detailed views are needed or performed intraoperatively. Invasive Arteriography coronary is also Usually Appropriate as it is the gold standard for defining the coronary anatomy that necessitates the surgery in the first place.

The rationale for prioritizing echocardiography, particularly TEE, centers on its ability to directly answer the key clinical questions with excellent spatial and temporal resolution, all without exposing the patient to ionizing radiation (O 0 mSv).

• Superior Visualization: TEE provides unparalleled views of posterior cardiac structures, including the left atrium, mitral valve, and thoracic aorta, which are often poorly visualized on TTE due to intervening lung and bone. This is critical for accurately grading mitral regurgitation and identifying aortic atheroma.
• Dynamic Functional Assessment: Echocardiography offers a real-time assessment of valvular function, wall motion, and hemodynamics, which is more informative for surgical planning than static anatomical images alone.
• Safety and Accessibility: As a non-ionizing modality, it can be performed at the bedside, in the pre-op holding area, or in the operating room without radiation risk.

Why are other advanced imaging modalities rated lower for this specific task?

• CTA coronary arteries with IV contrast is rated May be appropriate. While excellent for diagnosing coronary artery disease, its role in a patient whose anatomy is already defined by invasive catheterization is limited. It adds a significant radiation dose (☢☢☢ 1-10 mSv) and contrast load for information that is often redundant or better answered by echocardiography.
• MRI heart function and morphology is also rated May be appropriate. It provides excellent data on ventricular function and morphology. However, it is less effective than TEE for visualizing valvular detail and aortic plaque, is more time-consuming, and is less readily available in the immediate preoperative setting.

A standard preoperative chest radiograph (Usually Appropriate, ☢ <0.1 mSv) is also routinely obtained to assess for pulmonary pathology, effusions, or cardiomegaly, complementing the detailed cardiac assessment from echocardiography.

What Happens After the Preoperative Echocardiogram?

The results of the preoperative echocardiogram directly influence the final surgical plan and intraoperative management. The workflow branches based on the findings.

• If the study reveals significant, previously unrecognized valvular disease (e.g., severe aortic stenosis): The case is re-evaluated by the heart team. The surgical plan is typically modified to a combined procedure, such as CABG + Aortic Valve Replacement (AVR), to address both issues in a single operation.
• If the TEE shows severe, mobile atheroma in the ascending aorta: This finding is a major red flag for perioperative stroke. The surgeon will be alerted and may alter the operative technique. This could involve changing the cannulation site, using an epiaortic ultrasound probe intraoperatively to find a “clean” spot on the aorta, or performing the surgery off-pump without an aortic cross-clamp.
• If the study shows severely depressed left ventricular function: The anesthesia and surgical teams are prepared for a potentially difficult separation from cardiopulmonary bypass. Plans for postoperative inotropic support, mechanical circulatory support, and intensive care are confirmed.
• If the study is largely unremarkable (beyond the expected findings of ischemic heart disease): The planned CABG proceeds as scheduled, with the echocardiogram serving as a valuable baseline for comparison with the post-bypass intraoperative TEE.
• If a transthoracic echo (TTE) is indeterminate due to poor acoustic windows: This is a direct indication to proceed with a transesophageal echo (TEE) to obtain the necessary diagnostic information before the patient enters the operating room.

Pitfalls to Avoid (and When to Get Help)

Navigating preoperative planning requires attention to detail to prevent complications. Here are common pitfalls specific to this scenario:

• Assuming a normal valve exam:** Do not rely on auscultation alone. Subclinical but hemodynamically significant valvular disease can be missed without echocardiographic screening.
• Underestimating aortic disease:** Failing to specifically evaluate the ascending aorta for atheroma can lead to an avoidable embolic stroke. If TTE views are suboptimal, TEE is necessary.
• Ignoring the baseline chest radiograph:** Overlooking findings like a widened mediastinum, pulmonary nodules, or significant pleural effusions on the routine chest X-ray can lead to intraoperative surprises.