Recommendations for the use of bioresorbable vascular scaffolds in percutaneous coronary interventions : 2017 revision

BACKGROUND

To eliminate some of the potential late limitations of permanent metallic stents, the bioresorbable coronary stents or 'bioresorbable vascular scaffolds' (BVS) have been developed.

METHODS

We reviewed all currently available clinical data on BVS implantation.

RESULTS

Since the 2015 position statement on the appropriateness of BVS in percutaneous coronary interventions, several large randomised trials have been presented. These have demonstrated that achieving adequate 1 and 2 year outcomes with these first-generation BVS is not straightforward. These first adequately powered studies in non-complex lesions showed worse results if standard implantation techniques were used for these relatively thick scaffolds. Post-hoc analyses hypothesise that outcomes similar to current drug-eluting stents are still possible if aggressive lesion preparation, adequate sizing and high-pressure postdilatation are implemented rigorously. As long as this has not been confirmed in prospective studies the usage should be restricted to experienced centres with continuous outcome monitoring. For more complex lesions, results are even more disappointing and usage should be discouraged. When developed, newer generation scaffolds with thinner struts or faster resorption rates are expected to improve outcomes. In the meantime prolonged dual antiplatelet therapy (DAPT, beyond one year) is recommended in an individualised approach for patients treated with current generation BVS.

CONCLUSION

The new 2017 recommendations downgrade and limit the use of the current BVS to experienced centres within dedicated registries using the updated implantation protocol and advise the prolonged usage of DAPT. In line with these recommendations the manufacturer does not supply devices to the hospitals without such registries in place.

Shear stress in atherosclerosis, and vascular remodelling

Shear stress plays a role in lipid accumulation in primary atherosclerosis and vascular remodelling. We will present applications of a new technique, which enables to quantify shear stress in 3D vessel reconstructions. The method is based on 3D IVUS reconstructions of blood vessels either obtained by IVUS pull back (external iliac artery) or by a combination of angiography and IVUS (curved coronary artery). Distribution of wall thickness of a curved human right coronary artery was such that low wall thickness occurred where shear stress was high, and wall thickness was high where shear stress was low. Consequently, an inverse relationship between shear stress and wall thickness was detected. Although vascular remodelling after PTA in external iliac arteries of atherosclerotic Yucatan pigs was predicted both by acute gain and decrements in shear stress, the decrement in shear stress appeared a better predictor. In conclusion, shear stress appears to play a role in primary atherosclerosis and vascular remodelling after PTA.

Bacterial translocation in D-galactosamine-treated rats in a burn model

Bacteria and endotoxins can pass through the gut barrier under certain conditions. This process of bacterial translocation (BT) may occur after thermal injury in animals and is thought to play a role in the pathogenesis of septic complications in severely burned patients. The current study was performed to determine the role of endotoxin-related cytokines in the pathogenesis of burn-induced BT. Wistar rats were used in which enhanced sensitivity to TNF/LPS reactions was achieved by treatment with galactosamine (GalN). The GI tracts of these rats were antibiotic decontaminated with oral bacitracin and neomycin and were colonized with a neomycin resistant (NR)-Escherichia coli strain. The rats were divided into four groups, 30 per cent TBSA scald with GalN (Burn+GalN) pretreatment; 30 per cent TBSA scald without GalN (Burn); or sham injury with (GalN) and without GalN (Sham) pretreatment. On day 2, the animals were killed and liver, spleen, lung, heart and the peritoneal cavity were cultured. Blood samples were taken and the concentrations of LPS, TNF, IL-6 and ALAT were determined. Mortality was significantly increased in the Burn+GalN group compared to the other groups. In all groups, the incidences of BT were increased compared to the sham-treated group, although BT was most pronounced in the Burn+GalN group. In the latter group it was accompanied by highly elevated IL-6 and ALAT levels. The results of this study suggest that endotoxin mediators like TNF and IL-6 could play a role in the phenomenon of BT and that the function of the liver is an important clearing mechanism.