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Cardiac Biomechanics Lab »  Research »  Passive Constraint

Passive Constraint

The Acorn CorCap TM Cardiac Support Device (CSD) (Acorn Cardiovascular, Inc., St.Paul, MN) is a bidirectional woven polyester yarn jacket placed over the left (LV) and right ventricles (RV) in patients with dilated cardiomyopathy and heart failure. The underlying hypothesis is that the CSD will reduce strain and stress associated with progressive ventricular dilation. As a consequence, LV remodeling will halt or reverse cardiac remodeling, and systolic LV function will be chronically improved.

Pre-clinical studies showed that the Acorn CSD reduced end-diastolic volume without an increase in end-diastolic pressure or chamber stiffness. Surprisingly, the Acorn CSD also reduced end-systolic volume, improved isolated myocyte contraction, improved the affinity of the sarcoplasmic calcium pump SERCA2a for calcium, and increased the ejection fraction response to dobutamine. There was also evidence that the Acorn CSD altered post myocardial infarction remodeling, presumably by decreasing stress on the infarct border zone.

A randomized clinical trial of the Acorn CSD has been completed. As in pre-clinical studies, both end-diastolic and end-systolic volumes were decreased and there was an improvement in heart failure class. These findings occurred when the Acorn CSD was used alone or with mitral valve surgery. Despite the numerous pre-clinical and clinical findings, the exact mechanical effects of the Acorn CSD on ventricular wall stress remain unknown.