Experimental evaluation of different chordal preservation methods during mitral valve replacement.
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 end-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.
Moon
M R
MR
Department of Cardiovascular and Thoracic Surgery, Stanford University School of Medicine, California 94305.
DeAnda
A
A
Daughters
G T
GT
Ingels
N B
NB
Miller
D C
DC
D000818:Animals; D002815:Chordae Tendineae; D003971:Diastole; D004285:Dogs; D006350:Heart Valve Prosthesis / Q000379:methods*; D006439:Hemodynamics; D008943:Mitral Valve; D013599:Systole; D014021:Tissue Preservation / Q000379:methods*; D016277:Ventricular Function, Left