Experimental Study of the Dynamic Fontan Operation with an Electrical Preconditioned Skeletal Muscle Ventricle for the Univentricular Heart

(Department of Cardiovascular Surgery, Jikei University School of Medicine, Tokyo, Japan)

Yoko Matsumura Kiyozo Morita Katsushi Kinouchi
We have studied potential for pulmonary circulational assist by the dynamic Fontan model with a skeletal muscle ventricle (SMV) constructed using the latissimus dorsi muscles of 5 dogs. After 2 weeks of vascular delay, the SMV was electrically preconditioned for 8 weeks. Under cardiopulmonary bypass (CPB), the right heart (RV) bypass model was established with the SMV anastomosed between the right atrium and pulmonary trunk. The SMV was paced at a burst frequency of 25Hz, 60/min, with an asynchronization ratio. The aortic pressure (AoP), pulmonary arterial pressure (PAP), central venous pressure (CVP), and pulmonary flow (PAF) were measured. Just after on-SMV, PAP and PAF increased, CVP decreased. CVP decreased from 17}1.4mmHg to 13.5}0.7mmHg (p0.05). PAP increased from 20}2.8/19}1.6mmHg (non-pulsatile flow) to 37.5}4.9/18}2.1mmHg (pulsatile flow). After CPB, pulmonary vascular resistance (Rp) showed 5.9}1.5Wood units corresponding to a high risk factor for the Fontan procedure. On this Rp, under off-SMV the CVP was 18 mmHg and severe RV failure was recognized as PAF was 35% of the preoperative value. Under on-SMV, CVP decreased and PAF was almost the same as the preoperative value. On physiological CVP, an RV bypass model with intrathoracic SMV maintained PAF at the preoperative value under high Rp. We concluded that this model may be a viable surgical option for univentricular heart with high Rp, which may not be Fontan candidates.
@Jpn. J. Cardiovasc. Surg. 32F64 -68 (2003)