Abstract
The completely absorbable stents represent one of the latest innovations in the field of interventional cardiology, prospecting the possibility of “vascular repair”. In the published trials (ABSORB Cohort A and B, ABSORB EXTEND, and ABSORB II, III and IV) chronic total occlusions (CTOs) were considered an exclusion criteria. More recently the CTO-ABSORB pilot study demonstrated the safety and feasibility of bioresorbable vascular scaffold (BVS) use in case of CTO recanalization. We present the first case, to our knowledge, of in-stent occlusion successfully treated with an everolimus-eluting BVS and discuss its potential advantages in such kind of lesions.
We present the case of a 52 years old-man, ex-smoker, suffering from arterial hypertension and type 2 diabetes mellitus, with history of a previous antero-septal ST-elevation myocardial infarction (STEMI) treated by primary coronary angioplasty of left anterior descending (LAD) artery with implantation of a first-generation drug-eluting stent (DES) (2008). Due to the recurrence of effort angina he performed exercise test indicative of reduced coronary flow reserve. The coronary angiography showed proximal in-stent CTO of the LAD artery with visualization of the vessel through eterocoronary collateral circulations ( Fig. 1 ). The transthoracic echocardiogram showed mild left ventricular enlargement, preserved systolic function (ejection fraction 52%), hypokinesia of the anterior wall with preserved wall thickness and minimal mitral valve regurgitation. According to the Japanese-CTO score of complexity the lesion was classified as intermediate. We planned in-stent LAD artery CTO recanalization through bilateral radial approach. Percutaneous coronary intervention (PCI) was performed using an antegrade approach via the right radial artery and intravascular ultrasound (IVUS) guidance. We performed simultaneous right and left coronary angiography to guide the recanalization procedure ( movies 1 and 2 ). The intrastent CTO of LAD artery was successfully crossed using a Hi-Torque Pilot 50 guidewire advanced into a Finecross microcatheter (Terumo) ( Fig. 2 , A). After balloon dilatation (2.0 mm-diameter) we performed an IVUS study of LAD artery (IVUS catheter “Eagle Eye Platinum”, Volcano), following which we proceeded to treat the in-stent restenosis using a “cutting balloon” (Flextome 3.5–10 mm Cutting Balloon, Boston Scientific) and prepare the lesion with semi-compliant balloon dilatation, in order to allow a good strut apposition during BVS implantation ( Fig. 2 , B, C, D). Two overlapping everolimus 3.0 mm × 23 mm BVS (Absorb BVS, Abbott Vascular) were implanted from the proximal to the mid LAD. The scaffolds were then post-dilated with respectively a 3.0 mm and 3.5 mm non-compliant balloon, slowly inflated at high pressure. In our opinion the accuracy of BVS positioning and implantation was remarkably improved by use of the CLEARstent software (Siemens Healthcare Global). Specifically, use of the CLEARstent technology allowed to obtain a better visualization of the BVS’ thin structure and to precisely localize both the proximal and distal markers simplifying the double BVS overlapping implantation ( Fig. 2 , E). The final angiography showed a restored antegrade coronary flow TIMI 3 without residual lesions and/or intimal dissection ( Fig. 2 , F). The patient was discharged on the 2nd post-operative day on dual antiplatelet therapy (acetylsalicylic acid 100 mg plus Clopidogrel 75 mg). To the best of our knowledge, the present case is the first description of the use of a BVS to recanalize an in-stent CTO with IVUS-guided antegrade approach by bilateral radial access. The ABSORB BVS consists of resorbable polymers containing the antiproliferative drug “everolimus”. Prospective studies of BVS have shown favorable outcomes in simple, de novo coronary lesions with long-term positive vessel remodeling, late lumen enlargement and complete reabsorption of the vascular scaffold at follow-up . However, these studies specifically excluded in-stent restenosis (ISR) lesions and CTOs. In our opinion the BVS use in the current report was supported by the following reasons:
- (a)
the metallic struts of the previously positioned stent in the proximal LAD artery (preliminary dilated in order to reach the reference diameter needed to correctly implant the chosen BVS) assured the absence of early vessel wall “recoil” and an optimal landing zone during BVS implantation, allowing adequate expansion of these particular scaffolds in this setting;
- (b)
implantation of BVS, with subsequent reabsorption of its structure, would avoid layering multiple metallic struts inside the same vessel portion previously stented (proximal LAD artery);
- (c)
a local delayed hypersensitivity vasculitis was suspected to be the mechanism leading to late, acquired DES malapposition and restenosis with superimposed very late thrombosis. This hypersensitivity reaction has been attributed to the polymer coating of “eluting stents”, which significantly differs from the one used in the ABSORB BVS. The progressive total reabsorption of the BVS structures could avoid the long term exposition of metallic material and/or polymer coating (“allergic antigen”) to a vessel wall potentially producing hyperplastic and inflammatory cellular reactions;
- (d)
to preserve the surgical treatment, leaving the option of a future coronary artery bypass grafting (CABG) open in case of vessel re-occlusion.
