Partial Cardiac Denervation for Preventing Atrial Fibrillation After CABG (CALM)

CABG alone

Partial cardiac denervation + CABG. Partial cardiac denervation consists of transection of the ligament of Marshall and resection of the Waterston fat pad.

The intervention has been described in previous studies. Briefly, intraoperative partial cardiac denervation is achieved by transection of the left LOM and resection of the right Waterston fat pad using electrocautery.

During the procedure, the pulmonary trunk is first gently retracted to the right to expose the LOM located between the left atrial appendage and the left pulmonary veins. The LOM is then transected using electrocautery. Subsequently, the right atrium is retracted to the left to expose the Waterston fat pad located in the interatrial groove. The Waterston fat pad is completely excised with electrocautery down to the epicardial surface.

The proportion of participants with documented new-onset postoperative atrial fibrillation (POAF). POAF is defined as an episode of atrial fibrillation characterized by irregularly irregular RR intervals and the absence of discernible P waves, lasting more than 30 seconds. Continuous electrocardiographic recordings will be centrally reviewed by the blinded ECG Core Laboratory.

Time from surgery to the first occurrence of any component of the composite outcome, including all-cause death, stroke, systemic embolism, myocardial infarction, readmission for cardiac reasons, or post-discharge atrial fibrillation. Suspected clinical events will be adjudicated by an independent Clinical Event Adjudication Committee blinded to treatment allocation. Post-discharge atrial fibrillation events will be reviewed by the blinded ECG Core Laboratory.

The number of days from the date of surgery to hospital discharge.

Total medical costs incurred during the index hospitalization.

The proportion of participants who die from any cause during the perioperative hospitalization.

The proportion of participants who experience a new-onset stroke during the perioperative hospitalization, as adjudicated by the blinded Clinical Event Adjudication Committee according to predefined endpoint criteria.

The proportion of participants who experience myocardial infarction during the perioperative hospitalization, as adjudicated by the blinded Clinical Event Adjudication Committee according to predefined endpoint criteria.

The proportion of analyzable electrocardiographic monitoring time spent in atrial fibrillation during the early postoperative monitoring period, as determined by the blinded ECG Core Laboratory.

The total number of documented postoperative atrial fibrillation episodes per participant during the early postoperative monitoring period, as determined by the blinded ECG Core Laboratory.

The cumulative duration of documented postoperative atrial fibrillation episodes during the early postoperative monitoring period, as determined by the blinded ECG Core Laboratory.

The proportion of participants with atrial fibrillation documented after discharge by scheduled 3-day ambulatory electrocardiographic monitoring or by clinically obtained electrocardiographic recordings. All suspected events will be reviewed by the blinded ECG Core Laboratory.

The proportion of analyzable ambulatory electrocardiographic monitoring time spent in atrial fibrillation during each scheduled 3-day monitoring period, as determined by the blinded ECG Core Laboratory.

The proportion of participants with predefined non-atrial fibrillation arrhythmias, including third-degree atrioventricular block, frequent premature atrial contractions, and frequent premature ventricular contractions, as determined by the blinded ECG Core Laboratory.

Cardiac autonomic function will be assessed using time-domain and frequency-domain heart rate variability parameters obtained from electrocardiographic monitoring. Measurements will be centrally analyzed by the blinded ECG Core Laboratory.

Health-related quality of life will be assessed using the EuroQol 5-Dimension 5-Level Questionnaire (EQ-5D-5L). An EQ-5D-5L health utility index will be calculated using the Chinese population value set. The index ranges from -0.391 to 1.000, with higher scores indicating better health status. A score of 1.000 represents full health, 0 represents a health state equivalent to death, and negative values represent health states considered worse than death. Scores will be compared between the two treatment groups at scheduled follow-up assessments.

Atrial fibrillation-related quality of life will be assessed using the Atrial Fibrillation Effect on QualiTy-of-Life Questionnaire (AFEQT). The AFEQT Overall Summary Score ranges from 0 to 100, with higher scores indicating better atrial fibrillation-related health status and quality of life and lower scores indicating greater impairment. Scores will be compared between the two treatment groups at scheduled follow-up assessments.

The proportion of participants who require surgical re-exploration because of postoperative bleeding.

The proportion of participants who receive a blood transfusion after surgery during the index hospitalization.

The proportion of participants who develop new-onset moderate or greater pericardial effusion within 30 days after discharge from the index hospitalization, as documented by echocardiography.