An experimental rabbit model for off-pump left ventricular reconstruction following left ventricular aneurysm

Cardiac electromechanical remodeling following left ventricular reconstruction (LVR) surgery is not fully understood. Further development of an animal model will facilitate investigations in this area. In the present study, we aimed to establish a novel LVR procedure without the use of cardiopulmonary bypass in a rabbit left ventricular (LV) aneurysm model.

LV aneurysm was created in 6 rabbits by ligation of the distal left coronary artery. More than a month later, LVR aneurysm surgery was performed off-pump using a purse-string suture around the aneurysm. Cardiac dimensions and function were evaluated using echocardiographic techniques perioperatively and 4 weeks after LVR surgery. Six structurally normal hearts were used as controls.

LVR surgery was successfully performed in all 6 rabbits. Both LV end-diastolic volume (LVEDV, 4.6 +/- 0.9 to 3.3 +/- 0.6 mL; P < .01) and LV end-systolic volume (LVESV, 2.5 +/- 0.6 to 1.5 +/- 0.2 mL, P < .01) were decreased immediately postsurgery versus presurgery, and LV ejection fraction (LVEF) was increased (44.5 +/- 5.3 to 55.6 +/- 4.8%, P < .001). For comparison, in normal rabbits (n = 6), LVEDV, LVESV and LVEF were 3.1 +/- 0.7 mL, 1.2 +/- 0.5 mL, and 64.5 +/- 8.8%, respectively. During follow-up, one rabbit died 3 weeks after surgery from an unknown cause. In the remaining 5 animals, improvements of LVEDV (3.7+/- 0.4 mL, P < .05), LVESV (1.7 +/- 0. 3 mL, P < .01), and LVEF (53.1 +/- 2.8%, P < .01) were maintained versus presurgery values for more than 4 weeks after LVR.

Off-pump LVR of rabbit LV aneurysm is an effective and less invasive surgery that resulted in sustained improvement in cardiac function with no gross intraoperative or postoperative mortality. This may be a useful model for investigations of electromechanical remodeling following LVR.