Original Title: Is High Pressure Postdilation Safe in Bioresorbable Vascular Scaffolds? Optical Coherence Tomography Observations After Noncompliant Balloons Inflated at More than 24 Atmospheres.
Reference: Enrico Fabris et al. Catheter Cardiovasc Interv. 2016 Apr;87(5):839-46.

Courtesy of Dr. José Amadeo Guillermo Álvarez.

The mechanical properties of bioresorbable vascular scaffolds (BVS) are different from those of bare metal stents (BMS); given the risk of BVS fracture, high pressure post-dilation is not recommended. However, a thrombosis rate somewhat higher to that of new generation BMS suggests that, in addition to the correct preparation of the plate, it would be necessary some kind of post-dilation to optimize strut apposition and geometry.

The present publication analyzes optical coherence tomography images (OCT) from 22 Absorb bioresorbable scaffolds (Abbott Vascular, Santa Clara California) in 20 lesions from 16 patients undergoing post dilation with non- compliant balloons to 28 ±3.8 atm (range 24 to 40 atm), with a scaffold / balloon diameter/reference vessel diameter ratio of 1.02±0.11. 41% of cases, received high pressure balloons OPN NC (SIS Medical AG, Winterthur, Switzerland) at maximal pressure 30±4.7 atm.

Treated lesions were more complex than those habitually treated with this kind of scaffolds: 35% had moderate to severe calcification (by angiography), 20% involved bifurcation and 55% were ACC/AHA type C.

At final evaluation, there were no fractured devices, there was low residual stenosis area (16±9.6%) with minimal lumen area (OCT) of 5.5±1.4mm2 and only one case of dissected edge (4.5%) that did not require reintervention.

Conclusion
In the context of more complex lesions, post-dilation of bioresorbable scaffolds Absorb with very low compliance balloons and high pressure, with the adequate diameter/ scaffold/ balloon ratio, is safe, since there were no fractured scaffolds and expansion and apposition parameters are comparable to those obtained with less complex lesions.

Editorial Comment
High pressure post dilation has drastically reduced BMS subacute thrombosis rate; however, given the risk of fracture, there are concerns about using this technique with BVS. This is the first study to assess the Absorb BVS integrity after high pressure dilation in vivo and with OCT.

This study analyzed more complex lesions than those habitually treated with these devices, at extremely elevated pressure, with a high percentage of very low compliance balloons.

Outcomes show structure integrity and good area and apposition parameters and, even though further research and clinical follow up is necessary, post dilation could contribute to improve outcomes with this kind of scaffolds.

Courtesy of Dr. José Amadeo Guillermo Álvarez.
Chief of Hemodynamics and Interventional Cardiology at Buenos Aires German Hospital and Buenos Aires British Hospital, Argentina.