BVS: Controvertial Scaffold

Courtesy of Dr. Agustín Vecchia.

The advent of resorbable vascular scaffolds (BVS) generated high expectations among interventionists because of its potential advantages over bare metal stents. However, when comparing BVS against the Xience stent, we observed an increased rate of events associated to the first device, to their detriment. Among the reasons behind this poor performance was Absorb’s thicker, wider struts and the sub-optimal implantation techniques used in the first trials. Little has been said about the role of dual antiplatelet therapy (DAPT) in these scaffolds and their potential role in improved performance.

The aim of this study was to assess the impact of DAPT early termination on late and very late scaffold thrombosis (ScT) in patients treated with the Absorb BVS.

Data from registries of three centers were pooled (808 patients). The study analyzed a group of 685 patients who had received DAPT for at least 6 months and excluded the use of oral anticoagulants and early ScT. Definite/probable ScT incidence for the period on DAPT was compared to ScT incidence after DAPT termination.

Most patients had one lesion only, not complex, treated with 3.1±0.4 diameter and 20.9±5.8 mm length BVS. It is worth noting that IVUS was used in 31.3% of cases and post dilation in 56.7% (atmospheres were not reported).

 Read also: “Primary PCI with Bioresorbable Vascular Scaffolds”

 ScT incidence was 0.83 ScT/100 patients-year, with 95% confidence interval (CI): 0.34-1.98. After DAPT termination, the incidence was higher (1.77/100 patients-year; 95% CI: 0.66-4.72), compared to the incidence of the group on DAPT (0.26/100 patients-year, 95% CI: 0.04-1.86; p=0.12) and increased within the month after DAPT termination (6.57/100 patients-year, 95% CI: 2.12-20.38; p=0.01). There were no very late ScT in patients who continued on DAPT for a minimum of 18 months.

The authors concluded that late/very late ScT was acceptable and that it was low when patients were on DAPT, and potentially higher when DAPT was terminated before 18 months.

Editorial Comment

Despite differences were not significant (perhaps due to the low number of events), four out of five ScT cases took place after a year, when none of these patients were on DAPT. 3 of these four were off DAPT between 10 and 35 days prior the event, which suggests a time related reasons. Since data are negative, the number of patients and events is low, and this analyzis post hoc was not specifically designed to assess DAPT duration, which is why valuable data is missing, such as the reason behind termination (this is relevant data, for we know DAPT disruption and termination have different prognostic implications).

The present findings make it difficult to determine whether prolonged DAPT is the answer to BVS issues. However, it seems logical to think prolonged DAPT with BVS might reduce ischemic events in the long run, the same way they do with DES. Prolonged DAPT in addition to the use of guiding imaging seems to be the key to achieve good outcomes with BVS. Using the right strategy, Colombo and collaborators achieved 1.2% ScT in 264 consecutive patients treated with BVS at two year follow up (3 cases: 2 in the first 48 hrs. and one at 146 days in the context of early DAPT termination).

Courtesy of Dr. Agustín Vecchia.

Original title: Potentially increased incidence of scaffold thrombosis in patients treated with Absorb BVS who terminated DAPT before 18 months

Reference: 10.4244/EIJ-D-17-00119

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