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Effect of the Cox maze procedure on the secretion of atrial natriuretic peptide
1Department of Thoracic and Cardiovascular Surgery and Internal Medicine, Seoul National University College of Medicine, Korea.
Insights
The Cox maze procedure significantly decreases atrial natriuretic peptide (ANP) levels, potentially causing fluid retention. These ANP changes are linked to surgical alterations, not atrial fibrillation recurrence.
Area of Science:
- Cardiovascular Surgery
- Cardiac Electrophysiology
- Endocrinology
Background:
- The Cox maze procedure effectively treats atrial fibrillation.
- Fluid retention post-procedure is a concern, possibly linked to atrial natriuretic peptide (ANP) secretion.
- Understanding ANP dynamics is crucial for managing post-operative complications.
Purpose of the Study:
- To analyze serial changes in ANP levels after the Cox maze procedure.
- To compare ANP changes with those after coronary artery bypass grafting (CABG).
- To investigate ANP level differences in patients with and without transient atrial fibrillation recurrence post-maze.
Main Methods:
- Radioimmunoassay of plasma ANP levels from right and left atria, and radial artery.
- Serial blood sampling before and up to 7 days after Cox maze (n=19) and CABG (n=6) procedures.
- Correlation analysis between ANP levels, atrial pressures, and atrial fibrillation recurrence.
Main Results:
- A significant decrease (p < 0.001) in both right and left atrial ANP levels was observed post-Cox maze procedure.
- Impaired ANP secretion, not atrial pressure, correlated with decreased ANP levels.
- No significant difference in ANP levels was found between patients with or without transient atrial fibrillation recurrence.
Conclusions:
- The Cox maze procedure causes a significant reduction in ANP levels.
- This ANP decrease is a potential mechanism for post-operative fluid retention.
- Surgical modifications (atriotomy, auricle excision) likely cause ANP reduction, rather than rhythm conversion.
Objectives:
The Cox maze procedure has been confirmed to be effective in curing atrial fibrillation. Some authors have reported severe fluid retention after the Cox maze procedure and have suggested decreased secretion of atrial natriuretic peptide as a possible mechanism. This study was designed (1) to examine the serial changes in atrial natriuretic peptide after the Cox maze procedure as compared with changes occurring after coronary artery bypass grafting and (2) to elucidate any differences in atrial natriuretic peptide levels between patients with transient recurrence of atrial fibrillation after the Cox maze procedure and those without recurrence of atrial fibrillation.
Methods:
Blood samples were drawn from the right and left atria in patients undergoing the Cox maze procedure (n = 19) and from the right atrium in patients undergoing coronary artery bypass grafting (n = 6) before and 1, 2, and 3 days after the operation. In six patients undergoing the Cox maze procedure, samples were also drawn from the radial artery before and 1, 2, 3, 5, and 7 days after the operation. The plasma samples were prepared by refrigerated centrifugation and stored until radioimmunoassay. In the Cox maze procedure group, atrial natriuretic peptide levels in the right atrium were 629 +/- 366, 154 +/- 112, 162 +/- 112, and 183 +/- 97 pg/ml and those in the left atrium were 276 +/- 168, 152 +/- 91, 162 +/- 111, and 145 +/- 80 pg/ml before and 1, 2, and 3 days after the operation, respectively. A marked decrease in atrial natriuretic peptide levels was evident after the Cox maze procedure (p < 0.001). There was no significant correlation between atrial natriuretic peptide levels and atrial pressures after the Cox maze procedure, which suggests that secretion of atrial natriuretic peptide by the atria was impaired. There was a significant correlation between the atrial natriuretic peptide levels in the left atrium and those in the peripheral radial artery, and the decreased levels of atrial natriuretic peptide in the radial artery continued for 7 days after the Cox maze procedure. There were no differences in the atrial natriuretic peptide levels between the patients with transient recurrence of atrial fibrillation (n = 6) and those without recurrence (n = 13) after the Cox maze procedure. In the coronary artery bypass grafting group, the atrial natriuretic peptide levels in the right atrium were 115 +/- 37, 124 +/- 48, 154 +/- 54, and 156 +/- 36 pg/ml before and 1, 2, and 3 days after the operation, respectively. No change was seen after the operation.
Conclusions:
We observed a significant decrease in atrial natriuretic peptide levels after the Cox maze procedure. This may be one of the possible causes of fluid retention after this procedure. These decreased atrial natriuretic peptide levels after the Cox maze procedure may result from the multiple atriotomy incisions and excision of both atrial auricles performed during the procedure, rather than from the conversion of atrial fibrillation to normal sinus rhythm.