Updated Indications for Intraoperative TEE



Updated Indications for Intraoperative TEE


Daniel M. Thys



In the United States, intraoperative echocardiography (IOE) has become integral to the care of many cardiac surgical patients (1). In a recent survey of all active members of the Society of Cardiovascular Anesthesiologists (SCA) residing in the United States or Puerto Rico, Morewood et al. documented that 94% of respondents practice at institutions that use IOE (2). Furthermore, 72% of anesthesiologists working at such institutions responded that they personally employed transesophageal echocardiography (TEE) during anesthetic care.

Intraoperative echocardiography is widely used because it is thought to provide information that significantly influences clinical management and improves patient outcome. Although there is limited scientific evidence to substantiate such perception, several recent case series have documented the usefulness of IOE in adult cardiac surgery (3,4,5,6,7,8). Investigators have usually examined whether IOE yielded new information and how frequently the new information had an impact on anesthetic or surgical management. In adult cardiac surgery, the total number of patients included in these reports was 11,444 (Table 7.1). The incidence of new information ranged from 12.8% to 38.6%, while the impact on treatment ranged from 9.7% to 48.8%.

As in adult cardiac surgery, the use of IOE has become routine in many pediatric cardiac surgery centers. While epicardial echocardiography was used most commonly in the early years, the use of TEE has increased with the development of smaller TEE probes. Several recent studies have documented the utility of intraoperative TEE, particularly for the detection of residual defects after cardiopulmonary bypass (CPB) (9,10,11,12,13,14). These reviews reported on a total of 2,589 cases. The detection of significant residual defects after CPB ranged from 4.4% to 14.4% (Table 7.2).








TABLE 7.1. The Usefulness of IOE in Adult Cardiac Surgery































Number of Patients

New Information

Change in Management


3,245 (3)

15%

14%


851 (4)

—

14.6%


203 (5)

12.8%

10.8%


5,016 (6)

22.9%

—


238 (7)

38.6%

9.7%


1,891 (8)

—

48.8%









TABLE 7.2. The Usefulness of IOE in Pediatric Cardiac Surgery
























Number of Patients

Residual Defects


86 (9)

12.8%


200 (10)

10.5%


667 (11)

6.6%


1,000 (12)

4.4%


532 (13)

8%


104 (14)

14.4%


Because of their retrospective nature, most of these reports do not withstand rigorous scientific scrutiny. Nonetheless, they confirm the clinical opinion that IOE provides new information on cardiac pathology in a significant number of patients and that the new information results in frequent management changes. Most physicians who care for cardiac surgical patients believe these benefits to be real and have adopted the technique in their clinical practice.


PRACTICE GUIDELINES

In 1996, a task force of the American Society of Anesthesiologists/Society of Cardiovascular Anesthesiologists (ASA/SCA) published practice guidelines for perioperative transesophageal echocardiography (15). The recommendations of the task force address indications, the
clinical settings in which TEE should be considered, and proficiency, the cognitive and technical skills expected of anesthesiologists who perform perioperative TEE. The guidelines are evidence-based and focus on the effectiveness of perioperative transesophageal echocardiography (TEE) in improving clinical outcomes. A literature search conducted at that time retrieved 1,844 articles of which 588 were considered relevant to the perioperative setting.

The recommendations were divided into three categories based on the strength of supporting evidence or expert opinion that the technology improves clinical outcomes (Table 7.3). Category I indications are supported by the strongest evidence or expert opinion; TEE is frequently useful in improving clinical outcomes in these settings and is often indicated, depending on individual circumstances (e.g., patient risk and practice setting). Category II indications are supported by weaker evidence and expert consensus; TEE may be useful in improving clinical outcomes in these settings, depending on individual circumstances, but appropriate indications are less certain. Category III indications have little current scientific or expert support; TEE is infrequently useful in improving clinical outcomes in these settings, and appropriate indications are uncertain. The lack of supporting evidence for Category III indications is often due to the absence of relevant studies rather than to existing evidence of ineffectiveness. Thus, many Category III indications are worth investigating, but future research and technological developments may enhance their role in routine practice.

The recommendations refer to clinical problems rather than to individual patients, who often have more than one potential reason for performing TEE. Thus, although patients may not necessarily require perioperative TEE because they have a cardiomyopathy (Category III), the same patients may need TEE because of coexisting hemodynamic problems (Category I). Similarly, physicians must integrate multiple variables in assessing a patient’s need for TEE. Factors associated with the patient, procedure, and clinical setting each contribute to the overall risk of perioperative complications and cumulatively alter the benefit-harm ratio of using TEE. Physicians should consider each of these variables when calculating the appropriateness of using TEE.

In 1997, the American Heart Association (AHA) and American College of Cardiology (ACC) published guidelines for the clinical application of echocardiography (16). In 2000, the AHA/ACC task force was reconvened to update the guidelines. The American Society of Echocardiography was invited to participate in the development of the guidelines. The task force also decided to include a section on intraoperative echocardiography. In the preparation of this section, a literature search was conducted that identified an additional 118 articles related to the intraoperative use of echocardiography. The current text includes information that was retrieved in the most recent search and includes new recommendations for the clinical application of IOE. The indications for IOE provided in the new guidelines are based on the initial ASA/SCA guidelines as well as the newer information (Table 7.4).

The AHA/ACC guidelines utilize the following classification system for indications.

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/efficacy of a procedure or treatment.

IIa: Weight of evidence/opinion is in favor of usefulness/efficacy.

IIb: Usefulness/efficacy is less well established by evidence/opinion.

Class III: Conditions for which there is evidence and/or general agreement that the procedure/treatment is not useful/effective and in some cases may be harmful.


INDICATIONS FOR SPECIFIC LESIONS OR PROCEDURES


Adult Cardiac Surgery


Mitral Valve Repair

Two recent studies from Japan have confirmed the usefulness of intraoperative transesophageal echocardiography (TEE) for the assessment of residual regurgitation after mitral valve repair (17,18). Kawano et al. observed that 5 of 34 patients had 1 + regurgitation on postoperative ventriculography. Four of these patients demonstrated a maximal mosaic area > 2 cm2 on color flow Doppler by TEE immediately after cardiopulmonary bypass (CPB). They all developed rapidly progressing mitral regurgitation (MR) in the postoperative period. In a study by Saiki et al. (18), 40 of 42 patients with no or trivial MR (mosaic area < or = 2 cm2) also had no or trivial MR early and late postoperatively (12). The other two patients in whom moderate MR was detected intraoperatively by TEE, evolved to moderate regurgitation three months later.

Aklog et al. have recently examined the role of intraoperative TEE in the evaluation of ischemic mitral regurgitation (19). They studied 136 patients with a preoperative diagnosis of moderate ischemic MR, without leaflet prolapse or pathology, who underwent isolated coronary artery bypass grafting (CABG). They observed that intraoperative echocardiography downgraded MR in 89% of patients and that CABG alone leaves many patients with
significant residual MR. A reduction in the severity of mitral regurgitation when assessed by IOE was also reported by Grewal et al. (20). They studied 43 patients with moderate to severe MR and observed that, when assessed under general anesthesia, MR improved by at least one grade in 51% of patients.








TABLE 7.3. Indications for Perioperative TEE (15)















































































































Category I indications: Supported by the strongest evidence or expert opinion; TEE is frequently useful in improving clinical outcome in these settings and is often indicated, depending on individual circumstances (e.g., patient risk and practice setting)

Intraoperative evaluation of acute, persistent, and life-threatening hemodynamic disturbances in which ventricular function and its determinants are uncertain and have not responded to treatment

Intraoperative use in valve repair

Intraoperative use in congenital heart surgery for most lesions requiring cardiopulmonary bypass

Intraoperative use in repair of hypertrophic obstructive cardiomyopathy

Intraoperative use for endocarditis when preoperative testing was inadequate or extension of infection to perivalvular tissue is suspected

Preoperative use in unstable patients with suspected thoracic aortic aneurysms, dissection, or disruption who need to be evaluated quickly

Intraoperative assessment of aortic valve function in repair of aortic dissections with possible aortic valve involvement

Intraoperative evaluation of pericardial window procedures

Use in intensive care unit for unstable patients with unexplained hemodynamic disturbances, suspected valve disease, or thromboembolic problems (if other tests or monitoring techniques have not confirmed the diagnosis or if patients are too unstable to undergo other tests)

Intraoperative assessment of repair of cardiac aneurysms

Intraoperative evaluation of removal of cardiac tumors


Category II indications: Supported by weaker evidence and expert consensus; TEE may be useful in improving clinical outcomes in these settings, depending on individual circumstances, but appropriate indications are less certain.

Perioperative use in patients with increased risk of myocardial ischemia or infarction

Perioperative use in patients with increased risk of hemodynamic disturbances

Intraoperative assessment of valve replacement

Intraoperative detection of foreign bodies

Intraoperative detection of air emboli during cardiotomy, heart transplant operations, and upright neurosurgical procedures

Intraoperative use during intracardiac thrombectomy

Intraoperative use during pulmonary embolectomy

Intraoperative use for suspected cardiac trauma

Preoperative assessment of patients with suspected acute thoracic aortic dissections, aneurysms, or disruption

Intraoperative use during repair of thoracic aortic dissections without suspected aortic valve involvement

Intraoperative detection of aortic atheromatous disease or other sources of aortic emboli

Intraoperative evaluation of pericardiectomy, pericardial effusions, or evaluation of pericardial surgery

Intraoperative evaluation of anastomotic sites during heart and/or lung transplantation

Monitoring placement and function of assist devices


Category III indications: Little current scientific or expert support; TEE is infrequently useful in improving clinical outcomes in these settings, and appropriate indications are uncertain.

Intraoperative evaluation of myocardial perfusion, coronary artery anatomy, or graft patency

Intraoperative use during repair of cardiomyopathies other than hypertrophic obstructive cardiomyopathy

Intraoperative use for uncomplicated endocarditis during noncardiac surgery

Intraoperative monitoring for emboli during orthopedic surgery

Intraoperative assessment of repair of thoracic aortic injuries

Intraoperative use for uncomplicated pericarditis

Intraoperative evaluation of pleuropulmonary disease

Monitoring placement of intraaortic balloon pumps, automatic implantable cardiac defibrillators, or pulmonary artery catheters

Intraoperative monitoring of cardioplegia administration

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Jul 15, 2016 | Posted by in CARDIOLOGY | Comments Off on Updated Indications for Intraoperative TEE

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