Sympathetic denervation and reinnervation after the maze procedure

Area of Science:

• Cardiology
• Nuclear Medicine
• Cardiac Surgery

Background:

• The Maze procedure, used to treat atrial fibrillation during mitral valve surgery, may affect cardiac autonomic function.
• Previous studies suggest potential decreases in left ventricular ejection fraction (LVEF) and sinoatrial node response post-Maze.
• Factors influencing these cardiac sympathetic nerve changes remain unclear.

Purpose of the Study:

• To evaluate serial changes in cardiac sympathetic nerve distribution using 123I-metaiodobenzylguanidine (123I-MIBG) after the Maze procedure.
• To investigate the relationship between these nerve changes and left ventricular function post-surgery.

Main Methods:

• Thirteen patients with mitral valve disease were studied: 6 underwent Maze procedure with mitral valve surgery (Maze+) and 7 underwent mitral valve surgery alone (Maze-).
• Cardiac 123I-MIBG imaging and radionuclide ventriculography were performed preoperatively, 10 days, and 1 year post-surgery.
• Assessed parameters included 123I-MIBG uptake (heart-to-mediastinum ratio, H/M) and washout rate (WR), along with LVEF.

Main Results:

• The Maze+ group showed a significant decrease in LVEF and H/M at 10 days post-surgery, with significant recovery at 1 year.
• The Maze+ group exhibited a transient increase in WR at 10 days post-surgery.
• No significant changes in H/M or LVEF were observed in the Maze- group, which showed a decreased WR.
• Changes in H/M and WR significantly correlated with changes in LVEF in the Maze+ group.

Conclusions:

• Cardiac sympathetic nerves undergo denervation early after the Maze procedure, followed by reinnervation by late stages.
• These dynamic adrenergic nerve changes are associated with alterations in left ventricular function post-Maze procedure.