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Ann Thorac Surg 2002;74:1096-1097
© 2002 The Society of Thoracic Surgeons

Invited commentary

^a Temple University School of Medicine, Medical Research Building, Rm. 801, 3420 N. Broad Street, Philadelphia, PA 19140, USA

e-mail: wsantamo{at}unit.temple.edu

Cardiomyoplasty lives on in its legacy. While not currently a viable clinical option, the lessons and insights learned from cardiomyoplasty has influenced a new generation of passive devices to treat heart failure. Before cardiomyoplasty, surgeons avoided wrapping or restraining the heart. However, cardiomyoplasty showed that wrapping the heart, at least with a biological material, was tolerated; restrictive filling did not occur. Many believe that the primary benefit of cardiomyoplasty was due to this passive wrap, which slowed progressive left ventricular enlargement. In heart failure, as the ventricle enlarges, wall stress, the afterload on the cardiomyocytes, increases, leading to a decrease in the mechanical efficiency of the heart, more oxygen is consumed for the same amount of work. By limiting the increase in left ventricular end-diastolic volume, the passive property of cardiomyoplasty decreased peak left ventricular wall stress. As compared to controls, myocardial oxygen consumption decreased and the mechanical efficiency of the heart increased [1].

Kawaguchi’s article [2] shows an additional systolic advantage of cardiomyoplasty previously underappreciated, namely that active systolic contraction of the latissimus muscle, dynamic cardiomyoplasty, further increased the mechanical efficiency (the external work/MVO₂) of the heart. Thus passive devices may not reproduce the benefits of dynamic cardiomyoplasty. The simple assumption that the sole benefit was derived from the passive properties of cardiomyoplasty may not be true. Similar to cardiomyoplasty in initial clinical trials, restrictive filling problems have not occurred with the Acorn CorCap [3]. Additionally, experimental studies show that compared to controls, passive left ventricular restraining [4] or reshaping [5] devices increase the mechanical efficiency of the left ventricle. However, Kawaguchi’s article leaves us wondering if devices that restrain left ventricular end-diastolic volume and additionally provide some active systolic support may not be a better solution, and also serve as the true lesson learned from dynamic cardiomyoplasty.

References

1. Patel H.J., Pilla J.J., Polidori D.J., Sutton M.S., Lankford E.B., Acker M.A. Long-term dynamic cardiomyoplasty improves chronic and acute myocardial energetics in a model of left ventricular dysfunction. Circulation 1998;98:II346-II351.
2. Kawaguchi O., Huang Y.F., Yuasa T., Shirota K., Carrington R.A.J., Hunyor S.N. Sparing of myocardial oxygen by cardiomyoplasty: implications for mechanical direct cardiac compression. Ann Thorac Surg 2002.
3. Oz M.C., Konetz W.F., Kleber F.X., Mohr F.W., Gummert J.F., Ostermeyer J., Las M., Raman J., Acker M.A., Smedira N. Global surgical experience with the Acorn Cardiac Support Device. Proceedings of the 82^nd Annual Meeting of the American Association of Thoracic Surgery 2002;236.
4. Pilla J.J., Brockman D.J., Blom A.S., Yuan Q., Acker M.A. Passive ventricular constraint improves myocardial energetics in a model of heart failure secondary to acute infarction. Proceedings of the 82^nd Annual Meeting of the American Association of Thoracic Surgery 2002;76.
5. Inoue M., McCarthy P.M., Takagaki M., Ochia Y., Doi K., Faber C., Dessoffy R., Kopcak M.W., Jr, Fukamachi K. Energetic advantages of device-based left ventricular shape change. ASAIO J 2002;48:136.

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Personal Folders Download to citation manager Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Santamore, W. P. Search for Related Content PubMed Articles by Santamore, W. P. Related Collections Mechanical Circulatory Assistance