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Acute scaffold disruption rare after implantation of bioresorbable scaffold
New data from the ABSORB Cohort B trial indicate that the frequency of acute scaffold disruption is rare after implantation of the second-generation everolimus-eluting bioresorbable polymeric vascular scaffold.
Yoshinobu Onuma, MD, and colleagues aimed to assess the frequency and clinical impact of acute scaffold disruption and late strut discontinuity associated with the Absorb BVS (Abbott Vascular) in ABSORB Cohort B, a multicenter, single-arm trial designed to evaluate the safety and performance of the scaffold in 101 patients with de novo native coronary lesions.
For the current analysis, researchers assessed 51 patients from ABSORB Cohort B with 143 optical coherence tomography pullbacks; all had OCT at baseline and at post-procedure follow-up.
“A potential drawback of this new technology is the risk for disruption of the strut network when it is overexpanded. Historically, the phenomenon was documented for the first time in an anecdotal case from the ABSORB Cohort A trial. A 3-mm scaffold was overexpanded with a 3.5-mm balloon, resulting in scaffold disruption as documented by OCT. Due to the recurrence of anginal symptoms at 40 days, this patient underwent repeat revascularization despite an angiographically nonsignificant stenosis by quantitative coronary angiography.
“It is important that this acute mechanical disruption is distinguished from the structural discontinuity of the polymeric struts at a later stage, a biologically programmed process during the course of bioresorption,” Onuma and colleagues wrote.
Two (3.9%) of the 51 patients with post-procedure OCT imaging had acute scaffold disruption. Further, scaffold disruption at baseline was detected via IVUS in one patient. Target lesion revascularization related to the disruption was observed in one patient. Late acquired structural discontinuities at follow-up were reported in 21 (42%) of 49 patients without acute disruption. The only event associated with these late discontinuities observed on OCT at follow-up was one patient who had a non–ischemia-driven repeat TLR. The researchers observed no other major adverse cardiac events associated with these findings.
The analysis also concluded that quantitative coronary angiography did not detect some of the structural changes described in this study, whereas IVUS was able to detect some of the major changes (four of 23 cases).
“Acute scaffold disruptions are rare procedural phenomena that have been anecdotally associated with angina symptoms, although pathological correlation between disrupted struts and angina remain elusive. They can be generally avoided by respecting the stated expansion limits for each scaffold diameter. In case of recurrent angina without angiographic stenosis, OCT might be recommended as an additional technique, whereas the imaging follow-up later than 6 months needs a careful advance of the imaging device. Late discontinuations as a result of the expected resorption process … should be viewed as a serendipitous OCT finding of a normal bioresorption process without clinical implication,” the researchers concluded.
Disclosure: Onuma and colleagues report associations with a number of device and pharmaceutical companies, including Abbott Vascular.