Study of the traction resistance of mitral valve chordae tendineae.
OBJECTIVE
To determinate the extension and the resistance of the primary mitral valve chordae tendineae when submitted to traction. The importance of keeping the integrity of papillary muscle, chordae tendineae, and mitral valve cuspid when the replacement of this valve occurs is clear, but the knowledge of the maximum resistance that a primary tendinea chorda can withstand is not known.


METHODS
Eight hearts were dissected, and one hundred and thirty two primary human chordae tendineae were measured (length and thickness) and submitted to traction under controlled conditions so that the absolute resistance, resistance relative to thickness (relative resistance), and elongation could be measured.


RESULTS
The correlation between the elongation at the moment of rupture and the thickness was equal to 1.54 + 17.02 x thickness (P = 0.026); and to absolute resistance was equal to 0.95 + 1.42 x resistance (P < 0.001); and to the resistance relative to thickness (relative resistance) was equal to 1.95 + 0.08 x relative resistance (P = 0.009). The correlation between the absolute resistance and the thickness was equal to 0.26 + 14.53 x thickness (P < 0.001).


CONCLUSIONS
The resistance of primary mitral valve chordae tendineae is associated with its thickness and elongation at the moment of rupture, but is not associated with the length. The elongation at the moment of rupture shows a relationship with the resistance relative to thickness (relative resistance) and with the thickness of the primary chordae tendineae, but not with the length of the chordae tendineae.
Lobo
Frederico Lafraia
FL
Heart Institute, Hospital das Clínicas, São Paulo University Medical School, São Paulo, SP, Brazil. frede_lobo@yahoo.com.br
Takeda
Flávio Roberto
FR
Brandão
Carlos Manuel de Almeida
CM
Braile
Domingo Marcolino
DM
Jatene
Fabio Biscegli
FB
Pomerantzeff
Pablo Maria Alberto
PM
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002815:Chordae Tendineae / Q000502:physiology*; D004548:Elasticity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000502:physiology*; D009200:Myocardial Contraction / Q000502:physiology*; D010210:Papillary Muscles / Q000502:physiology; D012421:Rupture; D013314:Stress, Mechanical