Intraoperative Echocardiography in Low-Risk CABG Surgery

Default vs As-Needed Intraoperative Transesophageal Echocardiography (TEE) in Low-Risk Isolated Coronary Artery Bypass Graft (CABG) Surgery: A Randomized Controlled Trial

This goal of this study is to better understand when and where intraoperative transesophageal echocardiography (TEE) should (or should not) be used during coronary artery bypass graft (CABG) surgeries.

This trial will look at benefits and harms to two different treatments strategies in order to improve clinical outcomes. Intraoperative TEE is an ultrasound-based, imaging device that uses sound waves to look at the heart continuously during a heart surgery.

Inclusion Criteria:

1. Scheduled to undergo isolated CABG surgery at a hospital within the UPenn Health System
2. Age ≥18 years
3. Ejection fraction ≥50%
4. Transthoracic echocardiography within one year of scheduled surgery date
5. Left heart catheterization within one year of scheduled surgery date
6. English language fluency or facilitated via language interpreter
7. Able to provide informed consent either in English or via a language interpreter
8. Willing to comply with all study procedures

Exclusion Criteria:

1. Documented valve (aortic, mitral, tricuspid, or pulmonic) disease (stenosis or regurgitation) moderate or greater.

2. Any CABG surgery with either "possible" or "definite" aortic intervention listed as a planned part of the procedure. plan for either definite or possible surgical intervention.

3. Any CABG surgery with either "possible" or "definite" valve repair/replacement listed as a planned part of the procedure.

4. Having undergone any previous cardiac surgeries (i.e. scheduled with a "REDO" modifier).

5. Proximal/critical left main coronary disease (e.g. greater than or equal to 90% stenosis).

6. Preexisting anomalous coronary arteries

7. Preexisting end-stage renal disease on hemodialysis

8. Preexisting chronic kidney disease (CKD) stage 3, 4, or 5

9. Stroke with residual focal neurological deficit(s) within 90 days of surgery

10. Any of the following presurgical, mechanical circulatory support devices:

    1. Intraaortic balloon pump
    2. Percutaneous right ventricular assist device (RVAD)
    3. Impella
    4. Extracorporeal membrane oxygenation (ECMO)

11. Absolute contraindication to echocardiography defined as one or more of the following documented conditions:

    1. Esophagectomy
    2. Esophagogastrectomy
    3. Esophageal trauma

12. Any of these three relative contraindication to TEE:

    1. Esophageal varies
    2. Gastric bypass surgery
    3. Descending thoracic aortic aneurysm

13. Severe pulmonary hypertension defined as:

    1. Pulmonary arterial pressure ≥60 mmHg
    2. Pulmonary vascular resistance (PVR) ≥3 Woods Units

14. Hemodynamic instability after induction and following placement of an endotracheal tube will be defined as one or more of the following events or scenarios:

    1. Placement of an intraaortic balloon pump (IABP)
    2. Initiation of venoarterial extracorporeal membrane oxygenation (VAECMO)
    3. Placement of a right or left percutaneous mechanical circulatory support device
    4. Initiation of epinephrine infusion at a dose ≥ 6 mcg/min for a duration ≥5 minutes
    5. Initiation of norepinephrine at a dose ≥8 mcg/min for a duration ≥ minutes
    6. Initiation of phenylephrine infusion at a dose ≥100 mcg/min for a duration ≥ minutes
    7. Initiation of vasopressin infusion at a dose ≥0.04 units/min for a duration ≥ minutes