European Journal of Cardio-Thoracic Surgery, Vol 4, 445-449, Copyright © 1990 by European Association for Cardio-thoracic Surgery
Epicardial cryosurgery as used in ablation of accessory atrioventricular pathways: effect on valvular function in the dog
EW Jansen, EC Cheriex, I Kastelein, C Borst, PJ Slootweg and JF Hitchcock
Department of Cardiothoracic Surgery, University of Utrecht, The Netherlands.
Epicardial cryosurgery for ablation of atrioventricular accessory pathways
has surgical advantages. However, it is applied directly to the valve base.
To assess the risk of valve impairment, 10 anaesthetized dogs were
subjected to standardized epicardial cryosurgery of the right
atrioventricular junction. Two of these underwent sham procedure
(dissection only). Valve function was assessed by colour Doppler
echocardiography preoperatively and at 2 days, 1 week, 2 weeks and 10 weeks
postoperatively. Three out of the eight animals subjected to cryosurgery
developed moderate (grade 2/4) tricuspid insufficiency, which appeared at 1
week postoperatively, following regression of congestive oedema. Two out of
the three cases of TI were associated with leaflet prolapse. No tricuspid
insufficiency was seen in the sham-operated animals. At the end of each
interval two animals were killed for histological examination. Histological
examinations showed that cryolesions extended a maximum of 3 mm into the
valve leaflet. The tricuspid insufficiency is attributed to the extensive
scarring (including chondroid metaplasia), which causes retraction and
restricted motion of the annulus. It is concluded that cryolesions may
impair atrioventricular valve function. Patients undergoing cryosurgery
should be monitored postoperatively by echocardiography for
atrioventricular valve insufficiency.
