Invited commentary

Abstract

This article [1Boodhwani M. Cohn W.E. Feng J. et al.Safety and efficacy of a novel gel for vascular occlusion in off-pump surgery.Ann Thorac Surg. 2005; 80: 2333-2337Abstract Full Text Full Text PDF PubMed Scopus (25) Google Scholar] reports a prospective, experimental study in pigs of the use of a resorbable gel with reverse thermosensitive properties for temporary coronary artery occlusion. The gel is soft at room temperature and hardens at body temperature. Because the material is water soluble it dissolves in blood at a rate proportional to the amount and concentration of the gel applied. By measurement of blood flow, regional fractional myocardial shortening, and microvascular function, the gel was equivalent to occlusion with a standard microvascular clamp. The authors suggest that the gel may have a utility for vessel occlusion during off-pump coronary artery bypass graft surgery and may be less traumatic than mechanical occlusive devices like clamps or vessel loops.This interesting idea is well presented in this article. As the authors acknowledge, this preliminary study is limited by the fact that the experimental model is not truly analogous either to the diseased coronary circulation or to conditions during clinical off-pump surgery. Nonetheless, the idea is original and is likely to be of interest to surgeons committed to improving this technology.Among the questions that remain to be answered are the efficacy of this approach in diseased human coronary arteries in which collateral circulation may alter the quality and duration of vessel occlusion. Also, what is the proper technique for injection of the gel? Is there a risk of coronary injury even if a very fine gauge needle is used for injection? Can more gel be applied should the vessel open due to dissolution of the gel before the anastomosis is complete or if an additional suture is required? Is there any role for a catheter-based delivery system? Might gel fragments be a source of peripheral coronary emboli should the gel not dissolve at a uniform rate? Despite these remaining and potentially important unresolved issues, this is the type of incremental innovation that characterizes many complex techniques which are now considered the standard of practice in contemporary cardiac surgery. This article [1Boodhwani M. Cohn W.E. Feng J. et al.Safety and efficacy of a novel gel for vascular occlusion in off-pump surgery.Ann Thorac Surg. 2005; 80: 2333-2337Abstract Full Text Full Text PDF PubMed Scopus (25) Google Scholar] reports a prospective, experimental study in pigs of the use of a resorbable gel with reverse thermosensitive properties for temporary coronary artery occlusion. The gel is soft at room temperature and hardens at body temperature. Because the material is water soluble it dissolves in blood at a rate proportional to the amount and concentration of the gel applied. By measurement of blood flow, regional fractional myocardial shortening, and microvascular function, the gel was equivalent to occlusion with a standard microvascular clamp. The authors suggest that the gel may have a utility for vessel occlusion during off-pump coronary artery bypass graft surgery and may be less traumatic than mechanical occlusive devices like clamps or vessel loops. This interesting idea is well presented in this article. As the authors acknowledge, this preliminary study is limited by the fact that the experimental model is not truly analogous either to the diseased coronary circulation or to conditions during clinical off-pump surgery. Nonetheless, the idea is original and is likely to be of interest to surgeons committed to improving this technology. Among the questions that remain to be answered are the efficacy of this approach in diseased human coronary arteries in which collateral circulation may alter the quality and duration of vessel occlusion. Also, what is the proper technique for injection of the gel? Is there a risk of coronary injury even if a very fine gauge needle is used for injection? Can more gel be applied should the vessel open due to dissolution of the gel before the anastomosis is complete or if an additional suture is required? Is there any role for a catheter-based delivery system? Might gel fragments be a source of peripheral coronary emboli should the gel not dissolve at a uniform rate? Despite these remaining and potentially important unresolved issues, this is the type of incremental innovation that characterizes many complex techniques which are now considered the standard of practice in contemporary cardiac surgery.