Surgical Pathology of Atrial Appendages Removed during the Cox-Maze Procedure: A Review of 86 Cases (2002-2005)
Mathieu C Castonguay, Yinong Wang, Jacqueline L Gerhart, William D Edwards, Joseph J Maleszewski. Mayo Clinic, Rochester, MN
Background: Atrial fibrillation (AF) is a common cardiac arrhythmia that can complicate several forms of chronic heart disease. Persistent AF can be treated surgically with the Cox-maze procedure, which includes removal of one or both atrial appendages. To date, no large study has described the microscopic features of atrial appendages removed during the Cox-maze procedure.
Design: Atrial appendages, removed during the Cox-maze procedure from 86 consecutive patients with AF, were examined by microscopy and compared to atrial appendages procured at autopsy from 26 age-matched individuals without AF. Twenty additional control atria from individuals with heart disease but no AF were also obtained from our autopsy practice. Routine formalin-fixed, paraffin-embedded, H&E-stained sections were examined. Cases were also evaluated for amyloid with Congo red staining. The presence of moderate to severe myocyte hypertrophy, myocyte vacuolization, and interstitial fibrosis were noted. Additionally, any fatty infiltration, endocardial fibroelastosis, lymphocytic inflammation, thrombosis, and amyloid deposition was recorded. χ2 analysis was utilized to assess differences between the cohorts.
Results: Moderate to severe myocyte hypertrophy was noted more frequently in individuals with AF than in either control cohort; however, the difference was statistically significant only when comparing the AF group to the normal control (p<.02). Myocyte vacuolization was noted more frequently in individuals with AF than those without (p<.043). Like myocyte hypertrophy, interstitial inflammation was more frequent in the AF cohort than either control, but only exhibited statistical significance when compared to the normal cohort (p<.004). Fatty infiltration was seen significantly more often in those with AF (p<.007). Interstitial fibrosis was noted more frequently in diseased hearts, while no statistically significant difference was observed between the groups with respect to amyloid deposition. Endocardial fibroelastosis and thrombosis were not seen with increased frequency in the AF cohort compared to either of the controls.
Conclusions: This is the largest study to date that quantifies the histopathologic changes seen in atrial appendages removed during the Cox-maze procedure. Myocyte hypertrophy, myocyte vacuolization, interstitial lymphocytic inflammation and fatty infiltration occur more frequently in atria with AF than those without. Interstitial fibrosis is frequently encountered in diseased hearts (including AF).
Wednesday, March 21, 2012 1:00 PM
Poster Session VI # 38, Wednesday Afternoon