The Telescoping Suture –Part 1: Does this Technique Improve the Mechanical Behavior of a Biomaterial?: Calf Pericardium

Abstract

The authors study the mechanical behavior of calf pericardium employed in the construction of cardiac valve leaflets when subjected to telescoping suture, followed by tensile stress until rupture. One hundred twenty pericardial tissue samples were employed, 60 cut from root-to-apex and another 60 cut in transverse direction. Each of these two groups consisted of 12 control samples that were left unsutured and four sets of 12 samples each that were rejoined by telescoping suture using silk, Prolene, nylon or Gore-Tex., and subjected to tensile stress. At the rupture of the sutured tissues, the tensile stress of the suture materials ranged between 57.54 MPa for the series sewn lengthwise with Gore-tex and 114.08 MPa for the series sewn crosswise with silk. At these levels of stress, the deformation of the suture thread was much less marked than that of the calf pericardium, and internal stresses were produced that were difficult for the biomaterialto absorb. There was a loss of real load in all the sutured series when the observed resistance to rupture, expressed in kilograms, was compared with the estimated value. This loss of resistance did not invalidate the telescoping suture technique since the resistance to rupture was still much greater than that associated with suturing the two edges of the cut pericardium together. This report confirms the deleterious role of the shear force generated in the pericardium by the suture.