In vitro evaluation of platelet reactivity toward annuloplasty devices treated with heparin coating: Studies under flow conditions

Abstract

We have applied an in vitro perfusion model to explore the potential thrombogenicity of polyester annulolasty fabric used in valve repair and to investigate the possible thromboresistance characteristics conferred by a special heparin coating (Duraflotrade mark treatment). Samples of human blood from i) untreated or ii) heparin-coated extracorporeal circuits were recirculated through annular perfusion chambers containing a) untreated or b) treated annuloplasty cloth material. Perfusion experiments were performed at a shear rate of 600 s(-1) for 20 min. Platelet interaction with the material was morphometrically evaluated. In experiments performed with blood from untreated circuits and cloth material, the average cross-sectional area of platelet mass was 615 +/- 135 microm2. Treatment of cloth material with Duraflotrade mark statistically decreased the area of interacting platelets to 319 +/- 101 microm2 (*p < 0.05, n = 10). Blood samples from heparin-coated extracorporeal circuits showed a decrease of total area of platelets (308 +/- 58 microm2 vs 138 +/- 30 microm2, *p < 0.05, n = 9). The combined treatment of Duraflotrade mark in extracorporeal circuits and cloth material caused a more consistent reduction (p < 0.05). The in vitro perfusion experimental model was sensitive to evaluate the thrombogenic potential of Duraflotrade mark treatment. Our results indicate that the heparin coating of cloth material and extracorporeal circuits improves the biocompatibility of the original material and reduces the thrombogenic profile.

Evaluation of ion release, cytotoxicity, and platelet adhesion of electrochemical anodized 316 L stainless steel cardiovascular stents

“…The reduction in the thromboreactivity is desirable. Perfusion models using whole blood have shown to be a useful tool in the evaluation of the reactivity of platelets against biological and synthetic surfaces 27, 31. In this study, in vitro techniques were used to evaluate platelet interaction on stainless steel before and after an anodization treatment.…”

“…Perfusion models using whole blood have shown to be a useful tool in the evaluation of the reactivity of platelets against biological and synthetic surfaces. 27,31 In this study, in vitro techniques were used to evaluate platelet interaction on stainless steel before and after an anodization treatment. The advantage of these techniques is that allow us to detect differences in the thrombogenic profile of materials potentially used in cardiovascular surgery under flow conditions without any risk for the recipient and similar to occur under physiological conditions taking also into account the effect of blood rheology.…”

“…27 Despite the important efforts to develop thromboresistant surfaces, currently available biomaterials are not totally bland when in contact with blood. 27 Improvements in synthetic materials are necessary to reduce the thromboreactivity and avoid thromboembolic events including transient ischemic attacks and strokes.…”

“…As a result, thromboembolic complications can appear in patients with arterial grafts, artificial heart valves, annuloplasty devices, and other prosthetic devices 26. Pharmacological strategies with antiplatelet agents, have been developed and are used to prevent platelet interaction with artificial surfaces, but the success is limited 27. Despite the important efforts to develop thromboresistant surfaces, currently available biomaterials are not totally bland when in contact with blood 27.…”

“…Pharmacological strategies with antiplatelet agents, have been developed and are used to prevent platelet interaction with artificial surfaces, but the success is limited 27. Despite the important efforts to develop thromboresistant surfaces, currently available biomaterials are not totally bland when in contact with blood 27. Improvements in synthetic materials are necessary to reduce the thromboreactivity and avoid thromboembolic events including transient ischemic attacks and strokes.…”