8/19/2023 0 Comments Triple lumen catheter![]() When inflated in a resistant lesion, the balloon “hourglasses” or “dog bones” ( see Fig. As balloon pressure is increased, semicompliant balloons continue to expand in diameter. Therefore, when compared with a relatively compliant balloon, a noncompliant balloon will have a more predictable diameter at various inflation pressures and provide a greater amount of dilating force in a lesion. Balloon compliance prevents the dilating force from being concentrated in the region of the stenosis ( Fig. If the balloon material is compliant, increases in inflation pressure will result in further balloon expansion, especially in areas of lower resistance (i.e., in the adjacent normal vessel lumen rather than in the area of stenosis). The pressure that would cause permanent deformation of a noncompliant balloon (tensile strength) would approximate the pressure required to rupture the balloon (yield strength). A completely noncompliant balloon will not stretch beyond a predetermined diameter-despite increases in inflation pressure-and will maintain its profile and shape with repeated inflations ( Fig. Consequently, all balloons have some inherent degree of compliance. An atmosphere is a unit of pressure that will support a column of mercury 760 mm high at sea level and 0☌.įIGURE e5-3 For the same inflation pressure, balloon B will produce twice the dilating force of balloon A.Ĭompliance is a measure of how much a balloon will stretch beyond a predetermined diameter when a force is applied to it (Fig. The pressure within an angioplasty balloon is universally measured in atmospheres (atm). Similarly, larger vessels such as the abdominal aorta or the common iliac arteries require less pressure to dilate and rupture. ![]() Therefore, larger balloons will require less pressure than smaller balloons to generate substantial dilating force ( Fig. Because the tension on the balloon wall translates into dilating force, the dilating force generated by a balloon is directly proportional to the balloon’s diameter and inflation pressure. If the diameter of the balloon is kept constant, the tension on the wall of the balloon will increase linearly with increases in inflation pressure ( Fig. Thus, a balloon with twice the radius of a smaller balloon will exert twice the tension on the wall of a balloon for a given inflation pressure. 3, 4 The law of Laplace states that the force or tension (T) exerted on the wall of the inflated balloon is directly proportional to the pressure (P) within the balloon and the radius (R) of the balloon (T = P × R) ( Fig. It is dependent on balloon diameter, the balloon’s inflation pressure, compliance of the balloon material, balloon length, and the degree of stenosis. 3, 4 Dilating force is the outward force exerted against a luminal stenosis. It is important for one to understand the physical principles that govern the effects of balloon dilation.
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