The Absorb Limits

Abstract: A patient presented with an inferior non-ST segment elevation myocardial infarction and a tight lesion on the distal right coronary artery. After stent implantation, a large scaffold malapposition was observed by optical coherence tomography. This case emphasizes the importance of not expanding a bioresorbable vascular scaffold more than 0.5 mm over its nominal size.

J INVASIVE CARDIOL 2016;28(10):E122-E123

Key words: bioresorbable vascular scaffold, stent fracture

Case Presentation

In Figure 1A, a well-expanded scaffold (mean diameter, 3.4 mm) in a vessel of 4.1 mm reference diameter can be seen. According to the instructions for use, it was possible to postdilate with an NC balloon 0.5 mm bigger than scaffold size to avoid fracture, but in our case a larger diameter (4.1 mm) was needed. Therefore, progressive postdilation with 3.5 mm and 4.0 mm NC balloons was performed. Finally, a proper apposition reaching the 4.1 mm size without any scaffold fracture was achieved (Figures 1A and 1B; Video 2).

In the follow-up, 6 months later, the patient was readmitted with progressive effort angina and a severe angiographic scaffold restenosis was observed. By OCT, the angiographic restenosis corresponded to an scaffold fracture, covered by intimal hyperplasia just at the spot where the scaffold seemed well apposed previously (Figure 1C; Video 3). A 4.0 x 20 mm drug-eluting stent was implanted, covering the scaffold. 

The Absorb everolimus-eluting bioresorbable vascular scaffold (BVS) has represented a revolutionary concept in percutaneous coronary intervention technology. Despite the well-known advantages of BVS devices, we still have black spots that require greater understanding.^1,2 The polymeric devices have inherent limit of expansion and can break as a result of overdilation. Although the radial strength of BVS has been reported to be comparable to metallic stents, this is only true if the BVS is deployed within the limits of its size. If the BVS is overstretched beyond its designed limits, it may lose some of its radial strength and may indeed fracture.^3-5 Some cases of BVS target-vessel failure have been reported in different scenarios.^5-8

In our opinion, this case emphasizes the importance of not expanding the scaffold >0.5 mm over its nominal size. Even an optimal OCT result after postdilation does not preclude a scaffold fracture and a possible thrombosis/restenosis in the future. It is essential to further improve BVS technology to enhance stretchability of the devices while maintaining their radial strength.

References

1.    Iqbal J, Onuma Y, Ormiston J, Abizaid A, Waksman R, Serruys P. Bioresorbable scaffolds: rationale, current status, challenges, and future. Eur Heart J. 2014;35:765-776.

2.    Bourantas CV, Onuma Y, Farooq V, Zhang Y, Garcia-Garcia HM, Serruys PW. Bioresorbable scaffolds: current knowledge, potentialities and limitations experienced during their first clinical applications. Int J Cardiol. 2013;167:11-21.

3.    Ormiston JA, De Vroey F, Serruys PW, Webster MW. Bioresorbable polymeric vascular scaffolds: a cautionary tale. Circ Cardiovasc Interv. 2011;4:535-538.

4.    Foin N, Lee R, Mattesini A, et al. Bioabsorbable vascular scaffold overexpansion: insights from in vitro post-expansion experiments. EuroIntervention. 2016;11:1389-1399.

5.    Onuma Y, Serruys PW, Muramatsu T, et al. Incidence and imaging outcomes of acute scaffold disruption and late structural discontinuity after implantation of the Absorb everolimus-eluting fully bioresorbable vascular scaffold: optical coherence tomography assessment in the ABSORB cohort B trial (A Clinical Evaluation of the Bioabsorbable Everolimus Eluting Coronary Stent System in the Treatment of Patients With De Novo Native Coronary Artery Lesions). JACC Cardiovasc Interv. 2014;7:1400-1411.

6.    Ruiz-Salmerón RJ, Pereira S, de Araujo D. Bioresorbable vascular scaffold collapse causes subacute thrombosis. J Invasive Cardiol. 2014;26:E98-E99.

7.    Ho HH, Er Ching M, Ong PJ, Ooi YW. Subacute bioresorbable vascular scaffold thrombosis: a report of 2 cases. Heart Vessels. 2015;30:545-548.

8.    Tanaka A, Jabbour RJ, Kawamoto H, Latib A, Colombo A. Bioresorbable scaffold failure for recurrent restenosis at multi-layered stent fracture. Int J Cardiol. 2016;214:360-361.

From the University Hospital Juan Ramón Jiménez, Huelva, Spain.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.

Manuscript submitted June 2, 2016, provisional acceptance given June 6, 2016, final version accepted June 24, 2016.

Address for correspondence: Santiago J. Camacho Freire, MD, Ronda Norte S/N Secretaria de Hemodinámica, 1st Floor University Hospital Juan Ramón Jiménez,  CP 21005. Email: navallana@hotmail.com