Histologic evaluation of stapled right atrial appendages with fabric buttressing

Objective: The aim of this study was to histologically evaluate the importance of using buttressing materials in stapling the atrial appendages. Methods: We stapled the right atrial appendage with a commercial apparatus in 11 mongrel dogs. To evaluate the efficiency of using a buttressing material as an adjunct to stapling, we conducted 30-day studies without (group A: n = 2) or with buttressing material (group B: n = 3) and 90-day studies without (group C: n = 3) or with buttressing material (group D: n = 3) and thereafter made assessments using Doppler echocardiography and performed histologic analyses on all stapled appendages. Results: During surgery, blood oozing from the stapling sites was observed in four of five cases of groups A and C; with buttressing, there was no oozing in groups B and D. In groups A and B, we observed the myocardium of the appendage being focally replaced with fibrous tissue. Myocardium in group C was infiltrated diffusely with loose fibrous tissue and in group D had been almost completely replaced with fibrous tissue. Conclusions: The buttressing material was useful not only in preventing oozing but also likely promoting the growth of fibrous tissue in the right atrial appendage.