Transformation of Denervated Sleletal Muscle Graft By Chronic Electrical Stimulation and Application of Sleletal Muscle Graft for Reconstructive Cardiovascular Surgery.

2004 Fiscal Year Final Research Report Summary

• Project/Area Number: 15591496
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Thoracic surgery
• Research Institution: Jikei University School of Medicine
• Principal Investigator: MORITA Kiyozo Jikei University School of Medicine, Assistant Professor, 医学部, 助教授 (70174422)
• Co-Investigator(Kenkyū-buntansha): NAGAHORI Ryuuichi Jikei University School of Medicine, Assistant, 医学部, 助手 (50271309)
• Project Period (FY): 2003 – 2004
• Keywords: univentricular heart / electrical preconditioning / skeletal muscle graft / denervation / 再生心大血管外科

Research Abstract

PURPOSE : The purpose of this experimental study is to test the possibility of new surgical procedures of with denervated skeletal muscle graft with chronic electrical stimulation to avoid muscle atrophy, and the feasibility of dynamic Fontan procedure by paced skeletal muscle ventricle(SMV) to maintain physiological pulmonary circulation.
METHODS : Preliminary experiments in 10 beagles, left lattissimus dorsi muscle grafts were electrically stimulated for 28 days after the transaction of thoracodorsal nerve to test the effects of chronic stimulation on reversal of denervation-induced atrophy. On the basis of preliminary studies, we have studied potential for pulmonary circulational assist by dynamic Fontan model with Skeletal Muscle Ventricle(SMV) construced using the latissimus dorsi muscles of 10 dogs. SMV was electrical preconditioned for 8 weeks. Under cardiopulmonary bypass(CPB), right heart(RV) bypass model was established with SMV anastomosed between the right atrium and pulmonary trunk. SMV was paced at a burst frequency of 25Hz, 60/min., an asynchronization ratio. Aortic pressure(AoP), pulmonary arterial pressure(PAP), central venous pressure(CVP), and pulmonary flow(PAF) were measured.
RESULTS : Just after on-SMV, PAP and PAF were increased, CVP was decreased. CVP was decreased from 17±1.4 mmHg to 13.5±0.7 mmHg (p<0.05). PAP was increased from 20±2.8/19±1.6 mmHg (non-pulsatile flow) to 37.5±4.9/18±2.1 mmHg (pulsatile flow). Under off-SMV CVP was 18 mmHg and severe RV failure was recognized as PAF was 35% of preoperation. Under on-SMV, CVP was decreased and PAF was almost same as preoperation. On physiological CVP, RV bypass model with intrathoracic SMV keeped PAF as same as preoperation under high Rp. We conclued that this model may be aviable surgical option for univentricular heart with high Rp, which may not be a Fontan candidates.