Address for correspondence:
Gianluca Caiazzo MD PhD
Cardiology Unit
Ospedale San Giuseppe Moscati
Aversa
Italy
gianluca.caiazzo@gmail.com
Tel and fax: +390815001743
Case history : a 54 years old lady, active smoker with hypertension and hyperlipidemia, presented at our ED with atypical chest pain. EKG was unremarkable while echocardiogram showed mild inferior hypokinesia with normal LVEF (55%). Positive biomarkers for myocardial damage were found. After obtaining written informed consent, the patient underwent coronary angiography the same day of admission. A significant stenosis of the mid-right coronary artery (RCA) was found (Figure 1). Since the patient was young, the interventional plan was to implant a sirolimus-eluting bioresorbable magnesium scaffold on the mid-RCA via right radial artery access with OCT guidance. A 6 French Amplatz Left 1 guiding catheter was positioned at the RCA ostium and two workhorse coronary wires were passed through the lesion for higher support. Predilation with a 2.5 x 15 mm semi-compliant balloon at 12 atm was performed. OCT pullback showed a long significant stenosis with a balloon-induced dissection in the distal part of the lesion (mean vessel diameter 2.86 mm), an eccentric calcific plaque in the mid-segment and a normal vessel in the proximal landing zone (mean vessel diameter 3.38 mm) (Figure 2). Further 1:1 balloon/artery ratio pre-dilation was performed with a 3.0 x 15 mm non-compliant balloon at 12 atm. After checking for good expansion of the 3.0 mm balloon in two orthogonal views, a 3.0 x 25 mm sirolimus-eluting bioresorbable magnesium scaffold was implanted at 12 atm. Post-dilation with a 3.5 x 12 mm non-compliant balloon was performed at 18 atm (Figures 3 and 4). OCT evaluation revealed the extension of significant dissection (>300 μm) at distal edge (Figure 5). For this reason, the advancement of a second BRS was attempted, in order to cover the distal edge dissection. After two attempts, dislocation of the BRS from its delivery system occurred, with the BRS lying into the proximal segment of the coronary artery, proximally to the previously implanted scaffold (Figure 6). At this point, a thin-struts 3.5 x 26 mm drug-eluting stent (DES) was passed through the lost BRS in the proximal RCA and, after checking for sufficient overlapping with the first BRS implanted, the DES was deployed at 14 atm (Figure 7). The decision to deploy a DES (3.5 mm) within the dislocated BRS, instead of a expanding a balloon, was dictated by three main reasons: it was highly probable that the lost BRS might have reported some injury during its dislodgement (the dislodgement occurred pulling back the scaffold into the guiding catheter) which was not reassuring in terms of predictable outcomes; the dislocated BRS was a 3.0 mm scaffold, smaller than the vessel size in that segment; the dislocated BRS was not in overlap with the previously implanted scaffold. The distal edge dissection was then covered with a second 3.0 x 18 mm DES deployed at 14 atm (Figure 7). An OCT pullback was performed confirming good stents and scaffold apposition, short overlap between the BRS and the two DES, and presence of the lost BRS fully expanded and embedded into the vessel wall completely covered by the proximal DES struts (Figure 8). A final good result was obtained with a TIMI 3 flow (Figure 7). The patient was discharged after uneventful hospital stay two days later.
Follow-up : at 9-months angiographic follow-up the coronary artery looked good with TIMI 3 flow and absence of stent/scaffold restenosis (Figure 9). OCT analysis showed optimal stent apposition in the distal segment with no neo-intimal hyperplasia, advanced reabsorption process of the BRS in the mid-segment with black boxes still visible and good stent apposition in the proximal part with some non-significant acquired malapposition probably due to the dislocated BRS reabsorption between the vessel wall and the DES metallic struts (Figure 10).
Discussion : The rationale for using BRS during PCI are numerous since they provide temporary structural support to the vessel while eluting an anti-proliferative drug, and can be reabsorbed in a time-predictable fashion (1). The first BRS introduced in the market, the Absorb BVS, have shown, after initial positive results (2), higher scaffold thrombosis rates when compared to last-generation drug-eluting stents (3). Notwithstanding a limited clinical evidence available to date, magnesium-based BRS represent an interesting novelty in this field, promising higher radial force than PLLA-based BRS. Our case shows a good angiographic and OCT mid-term result after magnesium BRS implantation although a procedural complication occurred. OCT provided precious information for complication management and interpretation.
Author Contribution:
Gianluca Caiazzo conceived and wrote the manuscript draft.
Mario De Michele have been involved in drafting the manuscript and revising it critically for important intellectual content.
Luca Golino have been involved in drafting the manuscript and revising it critically for important intellectual content.
Vincenzo Manganiello have been involved in drafting the manuscript and revising it critically for important intellectual content.
Luciano Fattore have been involved in drafting the manuscript and revising it critically for important intellectual content and gave final approval of the version to be published.