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Ann Thorac Surg 1994;58:931-944
© 1994 The Society of Thoracic Surgeons

Articles

Experimental evaluation of different chordal preservation methods during mitral valve replacement

Marc R. Moon, MDa,b,c,1, Abe DeAnda, Jr, MDa,b,c,1, George T. Daughters, II, MSa,b,c, Neil B. Ingels, Jr, PhDa,b,c, D.Craig Miller, MD*,a,b,c

a Department of Cardiovascular and Thoracic Surgery, Stanford University School of Medicine, Stanford, USA
b Cardiac Surgery Section, Department of Veterans Affairs Medical Center, Palo Alto, USA
c The Research Institute of the Palo Alto Medical Foundation Palo Alto, California, USA

* Address reprint requests to Dr Miller, Department of Cardiovascular and Thoracic Surgery, Falk Cardiovascular Research Center, Stanford University School of Medicine, Stanford, CA 94305.

During chordal-sparing mitral valve replacement (MVR), some recommend anatomic reattachment of the anterior leaflet chordae to the anterior annulus; others advocate shifting the chordae to the posterior annulus. To compare the results of these techniques with those of conventional MVR (total chordal excision), 21 dogs were studied 5 to 12 days after implantation of tantalum markers to measure left ventricular volume and geometry. One to 3 weeks later, animals underwent conventional MVR (n = 7) or chordal-sparing MVR with either anterior chordal reattachment (n = 7) or posterior transposition (n = 7). Contractility was assessed using physiologic volume intercepts for end-systolic elastance, preload recruitable stroke work, and the relationship of the maximum rate of change of left ventricular pressure to the cnd-diastolic volume. The physiologic intercept for end-systolic elastance did not change after anterior or posterior MVR, but increased from 60 ± 14 mL before MVR to 72 ± 17 mL with conventional MVR (p < 0.002), indicating impaired left ventricular contractility. Similarly, the physiologic intercept for preload recruitable stroke work and the relationship of the maximum rate of change of left ventricular pressure to the end-diastolic volume increased 22% ± 13% and 28% ± 13%, respectively, after conventional MVR, but neither changed after anterior or posterior MVR. Although the end-diastolic pressure-volume relationship did not change with either chordal-sparing technique, its slope increased 98% ± 73% after conventional MVR (p < 0.008). Thus, although chordal preservation maintained better systolic and diastolic function, there was no substantial difference between the results of the anterior and posterior chordal-sparing techniques in this model.




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