An appropriately sized soft polyester external stent prevents enlargement and neointimal hyperplasia of a saphenous vein graft in a canine model

Abstract

Although the efficacy of external stents for vein grafts in coronary artery bypass grafting has been recognized, the ideal diameter and material of the stent remain controversial. We created a new external stent made of soft polyester mesh and performed an animal experiment using canines. Bilateral saphenous vein grafts were interposed in the bilateral common carotid artery of 10 beagles. The grafts in the left carotid artery were designated as the control group, and those in the right rolled by a soft polyester mesh external stent were designated as mesh group. Two of the 10 animals were sacrificed due to severe wound infection. The other eight were observed by echography for 6 months, and then grafts were extracted and thickness of the neointima of the grafts was measured. The control group showed 146% ± 26% postoperative enlargement of the internal diameter of the vein grafts after 6 months, whereas the mesh group showed only 115% ± 15% after the same duration (P = 0.0003). The median thickness of the neointima in the mesh group (170 µm [range: 150–190]) was significantly thinner than that in the control group (260 µm [range: 220–310], P < 0.0001). Some degree of correlation between the thickness of neointima and proportion of enlargement was noted (r = 0.518, P = 0.0024). A soft polyester mesh external stent for vein grafts successfully suppressed the enlargement of the vein grafts and thickness of the neointima after 6 months.

Perivascular CLICK‐gelatin delivery of thrombospondin‐2 small interfering RNA decreases development of intimal hyperplasia after arterial injury

“…The CLICK‐gelatin hydrogel, which is in direct contact with the adventitia is likely to be disrupting this process, leading to the downregulation of inflammatory signals following vascular injury. A similar response pattern has been previously demonstrated with the use of external stents in vein grafts 74,75 …”

“…A similar response pattern has been previously demonstrated with the use of external stents in vein grafts. 74,75 This study has limitations that should be addressed. First, the balloon angioplasty model is used to mimic the changes that lead to IH and restenosis of grafts following lower extremity bypass and may not perfectly reflect the changes that occur after surgical manipulation of diseased vessels.…”

The biomechanics and prevention of vein graft failure in coronary revascularization

“…Reminiscent of the "finger trap" concept first proposed in seminal work by Parsonnet et al, recent expandable stent devices have been made using braided cobalt-chromium alloy fibers in order to produce kink-resistant external supports capable of conforming to a variety of vessel diameters [20,33] . Likewise, efforts to minimize long-term foreign body reactions from non-degradable stents have led to the exploration of biodegradable materials including poly L-lactideε-caprolactone (75/25) copolymer (P (LA/CL)) mesh [34] and poly(ester urethane)urea (PEUU) [35] , the latter of which has been electrospun directly onto sheep saphenous veins to produce patient-specific external graft support [36] . .…”

Artificial Organs 2019: A year in review

“…Shota Yasuda et al of Yokohama City University, Yokohama, Japan investigated external stent to prevent enlargement and neointimal hyperplasia of saphenous vein graft in coronary bypass grafting in a canine model. They created an external stent made of soft polyester mesh.…”