Platelet deposition on stainless steel, spiral, and braided polylactide stents

Abstract

Platelets play a key role in (sub)acute thrombotic occlusion after stenting. We examined the possible differences between biodegradable polylactide (PLA) and stainless steel (SS) stents in platelet attachment and morphology after whole blood perfusion. PLA stents of different configurations (spiral/braided) and polycaprolactone-polylactide (PCL-PLA)-coatings, or SS stents were implanted into a PVC tube (Ø 3.2 mm), with or without precoating of the tube with type-I collagen. PPACK (30 microM)-anticoagulated blood with (3)H-serotonin prelabeled platelets was perfused (flow rate: 30 ml/min, 90 s) over the stents. Platelet deposition was assessed by scintillation counting and morphology by scanning electron microscopy (SEM). To examine coagulation activation, plasma prothrombin fragments (F1 + 2) were measured before and after the perfusion. Protein deposition on PLA/SS stents was assessed at augmented shear forces mimicking coronary flow (rate: 60 ml/min, 60 s) under minimal anticoagulation (PPACK 1 microM). More platelets deposited on PLA stents than on SS stents under all study conditions (p < 0.03). Under anticoagulation (PPACK 30 microM) the generation of F1 + 2 remained unaltered. Under higher flow rate and limited anticoagulation SS stents accumulated 3.27 +/- 0.75 microg and PLA stents 5.25 +/- 1.74 microg of protein (Mean +/- SD, p <0.95). Among all biodegradable stents, the braided PLA stent coated with PCL-PLA-heparin accumulated the fewest platelets (p < 0.02). In SEM, signs of platelet activation on braided heparin-coated PLA stents, when compared with uncoated braided PLA/SS stents, appeared modest. In conclusion, PCL-PLAheparin coating of biodegradable stents may enhance their hemocompatibility, expressed by less platelet deposition. Nevertheless, materials, design, and coating techniques of biodegradable stents must be further developed.

Functionalization of 3D printed polymeric bioresorbable stents with a dual cell-adhesive peptidic platform combining RGDS and YIGSR sequences

“…79 Hietala et al analyzed platelet deposition on stainless steel and PLLA stents, with the latter showing increased platelet adhesion. 13 However, when coating the PLLA stent with a PLCL layer, platelet attachment was effectively reduced. This behavior was also reported by Rudolph et al regarding the thrombogenetic potential of different polymers following a platelet activation test.…”

“…9–11 Other strategies involve the use of polydopamine (PDA) and polyethylenimine (PEI) as intermediates to incorporate an anti-platelet and anti-thrombotic drug 12 or an anticoagulant drug such as heparin. 13,14 Similarly, Meng et al 15 applied a layer-by-layer strategy to coat 316L stainless steel coronary stents with chitosan and heparin to accelerate re-endothelialization after coronary stent deployment. Alternatively, titanium oxide films have been reported as a suitable coating to improve endothelialization.…”

Surface Modifications of Medical Grade Stainless Steel

“…The MSS surface was coated with sulfonated CH using dopamine and PEG as anchors and was reported to limit platelet activation and clot formation, as well as calcium deposition [207]. The PCL-PLA-HEP coating enhanced hemocompatibility and reduced platelet deposition [208]. In a study, a small number of platelets adhered to alginic acid-immobilized MSS substrates [209].…”

Neoatherosclerosis after Drug‐Eluting Stent Implantation: Roles and Mechanisms

“…To investigate the biocompatibility of biodegradable polymers, cultured monocytes differentiated into functional macrophages were incubated with various polymers including poly-L-lactide, polycaprolactone, or poly-D,L-lactide-co-glycolide for up to 5 days and showed that biodegradable polymers were associated with macrophage adhesion, NADPH oxidase-induced generation of ROS, and excess apoptosis [ 89 ]. Furthermore, Hietala et al [ 90 ] examined the possible differences between biodegradable polylactide (PLA) and stainless steel (SS) stents in platelet attachment and morphology after whole blood perfusion. Results revealed that more platelets deposited on PLA stents than on SS stents under all study conditions ( P < 0.03), while among all biodegradable stents, the braided PLA stent coated with PCL-PLA-heparin accumulated the fewest platelets ( P < 0.02), indicating that materials, design, and coating techniques of biodegradable stents must be further developed.…”