INTERVIEW
A Polymer-free Drug-Filled Stent : The RevElution Trial
An Interview with Stephen Worthley , MD
A number of new stents have become available to cardiologists over the last few years . In this interview , CardioSource WorldNews speaks with Stephen Worthley , MD , professor and chair of cardiovascular medicine , and director of the cardiac catheterization laboratory at the University of Adelaide in Australia , about the next generation of stent evaluated in the RevElution Study .
CSWN : Describe for us the RevElution study and the stent . Stephen Worthley , MD : The RevElution study looks to be a revolution in interventional cardiology . The reason behind the name is the “ elution ” part of it , which is unique . So we know that drug-eluting stents ( DES ), which have become the mainstay of a treatment of patients with coronary artery disease , have a mechanism for delivering antiproliferative drug to the vessel to stop a re-narrowing — restenosis — by embedding these antiproliferative drugs in polymers .
Polymers are effectively a plastic coat that is around the stent . When the drug has eluted and gone away , generally speaking , the polymer stays behind . These plastics actually induce an inflammation , they ’ re an irritant , if you like , to the vessel wall ; this actually impedes the natural healing , a growing of skin — endothelium — over the stent . These polymers that have led to the issue around stents not healing as quickly and , therefore , getting clots on them or stent thrombosis . This new stent , which we evaluated in the trial , delivers and elutes the drug with the same sort of kinetics over the same time period as a current DES , but does not have a polymer at all . In this unique way , we ’ ve been able to core out , if you like , the internal part of the stent so that the stent itself is not any thicker . In fact , if anything , it ’ s thinner than a number of the current stents we use . We core out the inner part of it and put the drug inside the stent to act as a reservoir . We then drill tiny 20 micron diameter micro holes on the outer surface , the abluminal surface of the stent so that the drug just slowly elutes onto the vessel wall . And , therefore , allow for the efficacy so that you don ’ t see any re-narrowing — there ’ s now no polymer to induce an inflammatory response .
What else can you tell us about the study design and patients ? So at the moment , the RevElution Study has enrolled 75 patients . It ’ s a single arm observational first-in-human trial and multi-center . It includes centers mainly in Australia but also in Singapore and Brazil .
It is slightly complicated design in that we ’ ve
“ This new stent , which we evaluated in the trial , delivers and elutes the drug in the same time period as a current DES , but does not have a polymer at all .” embedded a number of imaging time points in some of the patients so that we can gain some insights from optical coherence tomography ( OCT )— a very high-resolution intravascular imaging technique — at early time points to see if that premise of early healing is in fact seen in the imaging .
And , indeed , through the complete dataset of all of the patients that have had 1 month OCT imaging , we saw what we thought we would see — early healing .
We had 15 patients in that study . We saw healing in effectively 90 % of the struts . At 1 month , we already saw an endothelium coat or covering over the stent struts . And yet , we saw , apart from that healing , very minimal intrusion into the vessel by that healing process , so it was over proliferative . In fact , the actual healing on average was a 60-micron neointimal inside the vessel .
OCT has sometimes delivered surprising images of the bioabsorbable stents — it was a very big surprise and researchers weren ’ t really predicting it . In this case , you ’ re seeing exactly what you wanted to see . It ’ s what we hoped to see , exactly right . You
To watch the fill interview with Stephen Worthley , MD , visit the CSWN YouTube channel or scan the QR code below .
never know until you do the trial , but it basically what we ’ d seen in that early preclinical work that indeed , we ’ d seen an early healing at 1 month . We ’ ve seen very low neointimal proliferation . We ’ ve seen very little malapposition , meaning where the stent itself is now is not adherent to the vessel wall . So it ’ s a malapposed strut — 1.5 %, which is actually very low because , in normal clinical practice , we ’ d expect somewhere between a 3 % to 7 % malapposed struts .
It ’ s 1-month data , but it ’ s the complete 1-month data set on the OCT sub-study and it ’ s very exciting . ■
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