Original title: The ABSORB EXTEND Study: preliminary report of the twelve-month clinical outcomes in the first 512 patients enrolled. Reference: Alexandre Abizaid et al.  EuroIntervention 2015;10:1396-1401.

The safety and efficacy of the Absorb Bioresorbable Vascular Scaffold (Absorb BVS) has been previously shown in 131 patients of the ABSORB trial cohorts A and B. 

Following this trial, the prospective single arm ABSORB EXTEND trial was design to expand the experience of the Absorb BVS outside the US, with broader inclusion criteria, including the treatment of longer lesions and multiple vessels disease. This article describes the clinical outcomes of the first 512 patients of this registry.  

The study intents to enroll 800 patients in more than 100 centers in five continents, and to include lesions up to 28 mm in length and reference vessel diameters between 2.0 – 3.3 mm (assessed by QCA or IVUS). Moreover, to include patients with multiple vessels disease, the study includes patients with up to 2 de novo coronary lesions, as long as both lesions are located in 2 different epicardial vessels. 

All events are assessed and adjudicated by an independent committee. Fort the 512 patients enrolled in the study, at one year follow up, the final end point composed by MACE and target vessel failure was 4.3% and 4.9% respectively. The definite or probable scaffold thrombosis rates, according to ARC criteria, was 0.8% at 12 months. 

Conclusion

The authors conclude that this interim analysis of the ABSORB EXTEND study shows low MACE and scaffold thrombosis rates, which represents a new step forward in the incorporation of bioresorbable scaffolds to the daily practice of cardiovascular intervention.  

Editorial Comment

Study limitations are several: 1) lack of a control arm, 2) possible selection bias associated to non-randomized studies, 3) the data correspond to an interim analysis of one part of the whole population (the first 512 of 800), 4) one year follow up may not be enough to analyze new technology.

Moreover, when analyzing the population characteristics, we see that 93% of enrolled patients had one vessel disease, the average length of lesions was 11.92 mm and the average stenosis was 59%, similar to ABSORB cohorts A and B, where we assessed a very interesting device against low complexity lesions. Larger studies, with longer follow up and more complex target lesions are necessary to define the scope of this kind of devices.   

Courtesy of Dr. Santiago F. Coroleu. Interventional Cardiologist
Santiago del Estero Cardiology Institute (Argentina).

Dr. Santiago F. Coroleu