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Ann Thorac Surg 2003;76:675
© 2003 The Society of Thoracic Surgeons

Invited commentary

^a 5455 Remington Rd., Las Cruces, NM, USA 88011

e-mail: gswmd{at}aol.com

One of the most vexing problems in the management of patients with aortic insufficiency is deciding when aortic valve replacement is indicated. If surgery is delayed too long, irreversible ventricular changes may occur, resulting in poor functional outcomes even after successful valve replacement. Until now, there has been no objective, reproducible way to determine the point at which ventricular decompensation occurs.

In the early stages of chronic aortic insufficiency, end-diastolic volume gradually increases, as does left ventricular stroke volume, so that normal forward flow is maintained. Laplace's Law states that wall stress is directly related to ventricular radius and is inversely related to wall thickness. Therefore, as long as compensatory hypertrophy thickens the wall as the ventricle dilates, systolic wall stress will not increase. Eventually, however, myocardial contractility decreases and end-systolic volume increases, but wall thickness fails to increase proportionately, leading to increased end-systolic wall stress (ESS). This change marks the beginning of ventricular decompensation.

In the past, the usefulness of ESS measurements has been limited by the need to make estimates based on simplified geometric assumptions (such as the ventricle being spherical). Cupps and his colleagues have made a breakthrough in this area by the ingenious use of finite element analysis in six portions of the left ventricle, using MRI and noninvasive carotid waveforms. Unlike earlier methods, finite element analysis can measure and calculate the effects of variations in left ventricular wall thickness and curvature on ESS. This landmark paper introduces a powerful and sophisticated new tool that will increase our understanding of left ventricular pathophysiology. Although it will take further study and long-term follow-up before we can use ESS for clinical decision-making, the window has been opened, giving us our first dynamic, detailed look at left ventricular dysfunction.

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 Author home page(s): Gerald S. Weinstein Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Weinstein, G. S. Search for Related Content PubMed Articles by Weinstein, G. S.