Abstract
Transesophageal echocardiography (TEE) for intraoperative planning is well recognized by surgeons, cardiologists, and anesthesiologists. Current guidelines support the utilization of TEE in all open heart and thoracic aortic procedures, and it should be considered in patients having coronary artery bypass grafting. In noncardiac surgery, TEE should be used when unexplained life-threatening circulatory instability persists despite corrective therapy (rescue TEE). As an intraoperative monitor, TEE may be used when the nature of the planned surgery or the patient’s known or suspected cardiovascular pathology might result in severe hemodynamic, pulmonary, or neurologic compromise. The intraoperative echocardiographer is an integral part of the surgical team and the information provided has a significant impact on anesthetic patient management, surgical planning, and patient outcomes.
Keywords
cardiac surgery, intraoperative echocardiography, noncardiac surgery, teamwork, transesophageal echocardiography
Introduction
Transesophageal echocardiography (TEE) for intraoperative planning is well established in the armamentarium of surgeons, cardiologists, and anesthesiologists. The use of intraoperative TEE has become the standard of care during cardiac surgery, and the intraoperative echocardiographer (IE), generally an anesthesiologist, has become an integral part of the cardiac surgery care team. This chapter will review the role of the IE and the intraoperative examination.
Role of the Intraoperative Echocardiographer
The IE is an integral part of the cardiac surgical team ( Box 49.1 ). The concept of an effective cardiac surgical team needs to emphasized. It is a group of individuals with an expressly agreed common goal who hold themselves mutually accountable for the outcome of the patient, which can depend enormously on how the team functions. Developing a culture of teamwork and effective communication has been shown to reduce mortality in the operative environment. Specifically in cardiac surgery, understanding the complex interactions during a cardiac surgical case likely improves patient safety and effective teamwork. The IE needs to develop an understanding of each team member in the cardiac operating room and their individual contribution to the overall success of the procedure at hand. This may be very different from other environments that they are typically used to working in outside the operating room.
Cardiac surgeon
Cardiac anesthesiologist
Intraoperative echocardiographer
Perfusionist
Physician assistants
Nurses
Fellows
Residents
Surgical technicians
The IE should be present during critical components of the operation to optimize their impact on the success of the procedure. The IE is a co-proceduralist, where a successful surgical outcome is dependent on their expert input, based on information obtained from the intraoperative TEE exam, and is communicated to the entire surgical team. As has been reported, information obtained from an intraoperative TEE exam has significant impact on anesthetic patient management, surgical planning, and patient outcomes. The primary objectives of the comprehensive intraoperative exam are to confirm the primary diagnosis and assess for any new pathophysiology, to discuss the exam, including its impact on anesthetic management, and to guide and assess the surgical outcome. The goal is an interdisciplinary plan of action at each stage of the operative procedure (precardiopulmonary bypass [CPB], during CPB, separation from CPB and post-CPB).
Impact of Intraoperative Transesophageal Echocardiography in Cardiac Surgery
Several studies have supported the utilization of TEE in the intraoperative cardiac surgical arena. Minhaj et al. reported on 283 consecutive patients undergoing cardiac surgery. There were 106 new TEE findings in 87 patients with half of the new findings involving the mitral valve and a quarter involving the tricuspid valve. The new findings altered surgical management 25% of the time. In addition, information obtained from the intraoperative TEE exam influenced the need for CPB in 3% of patients. In two patients, the TEE exam prompted reinitiating CPB, and in one patient, TEE information cancelled the proposed surgery. Eltzschig et al. reviewed the impact of intraoperative TEE on surgical decisions in 12,566 consecutive patients undergoing cardiac surgery at a single institution. Overall, the intraoperative TEE exam performed before and after CPB influenced the cardiac surgical decision making in more than 9% of all patients studied. TEE had the greatest impact in patients having combined coronary artery bypass grafting (CABG) and a valve procedure (12.3% pre-CBP, 2.2% post-CPB), followed by isolated valve procedures (6.3% pre-CPB, 3.3% post-CPB), and then CAGB alone (5.4% pre-CPB, 1.5% post-CPB). Mishra et al. reported on 5016 consecutive cardiac surgical cases where TEE was utilized during the procedure. Overall, the authors reported that 39% of patients benefited from TEE during the pre-CPB period with similar benefit during the post-CPB exam. TEE guided hemodynamic interventions helped or modified the surgical plan, and identified post-CPB issues, such as the need for bypass graft revision or inadequate valve repair. See Table 49.1 for the most common changes in surgical management and related new intraoperative TEE findings.
| Procedure Either Altered or Added | New Findings on Exam |
|---|---|
| Tricuspid repair or replacement | Tricuspid regurgitation |
| Mitral repair or replacement | New significant regurgitation Absence of regurgitation Vegetations Leaflet perforation or chordal rupture Annular calcification |
| Aortic repair or replacement | New significant regurgitation or stenosis Vegetations or abscess Absence of regurgitation Subaortic membrane |
| Atrial septal defect or patent foramen ovale repair or closure | New or significant defect |
| Intra-aortic balloon pump insertion | Ventricular failure or ischemia |
| Ascending aortic aneurysm repair | Aneurysm |
| Off-pump CABG instead of on-pump | Calcified ascending aorta |
| VSD closure | New or significant defect |
| LVAD insertion | Ventricular failure or ischemia |
| Thrombectomy | Thrombus noted on exam |
| Case cancelled | Multiple etiologies |
| Abandon minimally invasive approach | — |
Current guidelines by the Society of Cardiovascular Anesthesiologists, the American Society of Anesthesiologists, and the American Society of Echocardiography have further established the role of TEE in cardiac surgery:
Cardiac Surgery (for Adult Patients Without Contraindications)
- 1.
TEE should be used in all open heart and thoracic aortic surgical procedures
- 2.
TEE should be considered in patients having coronary artery bypass graft surgery
Objectives of the Intraoperative Tee Exam
The information obtained from a comprehensive intraoperative exam should confirm and refine the preoperative diagnosis ( Box 49.2 ). This is based on studies showing the utility of intraoperative TEE, especially in valve and aortic surgery. In addition, intraoperative TEE has been shown to detect new or unsuspected findings as part of the comprehensive pre-CPB exam. The information learned from the pre-CPB exam should be integrated into the anesthetic management of the patient and the surgical plan should be readjusted accordingly. Finally, TEE should assess the results of the surgical intervention to optimize patient outcomes and determine the need to re-initiate CPB if the result of the exam or new findings deem it necessary ( Box 49.3 ).
Confirm and refine the preoperative assessment
Determine the need for unplanned surgical intervention
Determine cardiac dysfunction that impacts patient management
Cannulation and perfusion strategy
Address surgical procedure-specific issues
Predict complications related to the proposed surgical intervention
Assess surgery specific results after separation from CPB, in addition to a global assessment structure and function
CPB, Cardiopulmonary bypass.
Additional bypass graft or revision
Revision of valve repair or replacement
Additional valve procedure
Ventricular dysfunction
Mass resection or thrombectomy
Dissection or ascending aortic repair
Ventricular septal defect or atrial septal defect
Further de-airing or revision of drug administration
The Intraoperative Transesophageal Echocardiography Exam
The best way to examine the role of the IE is to give a detailed example of a patient in the operating room with primary mitral regurgitation for mitral repair. The role of the IE and the steps of the exam can be applied to any surgical procedure where intraoperative echocardiography is utilized.
Ideally, the IE has reviewed all preoperative imaging and already discussed a preliminary assessment of mechanism and function of the mitral valve with the surgeon prior to the patient entering the operating room. This type of collaboration between the surgeon and the IE fosters a relationship that is paramount not only to the current patient’s outcome but also to the long-term success of the surgical program. The pre-CPB exam should include confirming and refining the diagnosis, determining the need for unplanned surgical intervention, planning a cannulation and perfusion strategy, addressing surgery-specific issues, and anticipating postrepair complications ( Table 49.2 ).
| Intraoperative Exam | Examples of Findings |
|---|---|
| Confirm and refine the preoperative assessment | Confirm and refine the mechanism, location, and severity of mitral regurgitation using 2D/3D imaging and Doppler assessment of the mitral valve |
| Determine the need for unplanned surgical intervention | Secondary pathophysiology related to severe mitral regurgitation New unexpected findings that should be addressed during the surgical intervention (moderate/severe tricuspid regurgitation) |
| Determine cardiac dysfunction that impacts patient management | Unexpected ventricular dysfunction Aortic regurgitation Left-sided superior vena cava (impacts coronary sinus retrograde cardioplegia) |
| Cannulation and perfusion strategy | Finding a significant patent foramen ovale shunt may impact the type of cannulation performed or surgical approach |
| Address surgical procedure-specific issues | Repair or replace the valve |
| Predict complications related to the proposed surgical intervention | Postrepair mitral stenosis Systolic anterior motion of the anterior leaflet of mitral valve producing left ventricular outflow tract obstruction Risk of atrial ventricular dissociation due to significant mitral annular calcification debridement Ventricular dysfunction |
The initial pre-CPB TEE exam should be comprehensive (see Chapter 4 ). The information obtained needs to be communicated in a timely manner to other members of the cardiac surgical team as this may impact pre-CPB management of the patient, the cannulation and perfusion strategy, and the need for additional surgical intervention. The focus of the exam then turns to the primary pathology, in this case the mitral valve. The IE should incorporate two-dimensional (2D) and three-dimensional (3D) imaging along with Doppler interrogation of the mitral valve to determine the mechanism, location, and severity of the mitral regurgitation ( Fig. 49.1 ). The IE evaluates all aspects of the mitral apparatus (annulus, leaflets, chordae, papillary muscles, and left ventricle) to determine their individual and collective impact on the mechanism of mitral regurgitation ( Figs. 49.2 to 49.7 and 
). For successful valve surgery, determining the precise mechanism of valve dysfunction can be the most important aspect of the intraoperative exam (see previous chapters specific to each valve and ventricular pathology). Specific to mitral repair, Shah and Raney recently published a modification of the classic Carpentier description of leaflet motion, which incorporates our greater understanding of leaflet motion pathology since the original publication in 1983 ( Table 49.3 ).
