Interview by Jennifer Ford
Francesco Liistro, MD, is the principal investigator of the DRASTICO trial, which compares drug-coated balloon and drug-eluting stent strategies in complex peripheral superficial femoral artery and popliteal interventions. He spoke at the 43rd Annual VEITH Symposium on the initial results of this study now that the investigators have completed enrollment for 60% of the study population.
VDM: Please give us a little background on the DRASTICO trial.
LIISTRO: The DRASTICO trial compares drug-coated balloon (DCB) and drug-eluting stent (DES) in complex peripheral superficial femoral artery (SFA) and popliteal interventions. The study is a single-center randomized trial. The DCB is Medtronic’s In.Pact Pacific, and the DES is Cook Medical’s Silver PTX. We have now enrolled almost 90% of the required sample size, which is 250 patients (125 in each arm), and so we will present the preliminary data related to about 60% of the population.
VDM: Can you share a little about the DRASTICO data?
LIISTRO: This trial is interesting because these are not simple lesions in SFA claudicants. These are the patients we treat every day, who are mostly affected by critical limb ischemia. More than 50% of these patients undergo a combined below-the-knee intervention. These patients have long lesions – the mean lesion length in both groups is approximately 17 cm. Over 50% have totally occluded vessels, and 40% are severely calcified. So these are not easy lesions or easy patients. Most of these patients are affected by diabetes mellitus. In these patients, we have previously reported in the DEBATE-SFA trial that simple nitinol stenting resulted in a restenosis rate of about 47%, while the combination of nitinol stenting with DCB resulted in a much lower restenosis rate of about 17%.
In 2013, when we designed the DRASTICO study, we didn’t have the results from the Silver PTX in everyday practice. We named this the “DRASTICO” study because clinicians have to make a drastic decision about whether the DCB or DES is a more successful strategy. For the purpose of this study, we assumed that the restenosis rate for DES was 30% and that we could lower the restenosis rate to 15% with DCB. We wanted to create a superiority trial with a sample size of 250 patients according to a power of 80%. If we had designed a non-inferiority trial, we would have needed about 600 patients, and we could never have done the study at only one center.
At this point in the trial, the restenosis rate in this population is 27% for DCB and 30% for DES. There was no significant difference between the two different strategies. We found an occlusive restenosis rate of 9% for DCB and 12% for DES. There is a little difference in the kind of lesion undergoing revascularization in favor of DCB, but it’s not significant and might be due to the presence of critical limb ischemia, so some of these repeat angioplasties in the SFA could be triggered by below-the-knee disease. Otherwise, we could imagine that there’s a difference in the clinical impact of in-stent restenosis compared with restenosis after DCB. Maybe in-stent restenosis could be more aggressive and may lead to more symptoms, and that’s why you have more TLR after DES implantation. However, these are only the preliminary results, and must be confirmed in the entire patient population. I believe we’ll have the final result at VEITH 2017.
However, in this complex patient and lesion subset, it’s very important that we obtain a 13-month follow-up primary patency result of 77.3%, which is very similar to the single-arm registry reported by Antonio Micari in long lesions and also very similar to a registry reported by Andres Schmidt in 2013 with DCB with provisional stenting. So to date, there is no difference between DES versus DCB followed by provisional stenting. The provisional stenting rate in DRASTICO is only about 17%. However, both DES and DCB strategies are better than doing nitinol stent alone, because if you compare the results of the DRASTICO study (lesion length, 17 cm) with the nitinol stent arm of the DEBATE-SFA trial (lesion length, 9 cm), despite the longer lesion length, the DRASTICO restenosis rate is only 30%, whereas the nitinol stent arm of DEBATE-SFA restenosis rate is 47%.
VDM: The drug-eluting technology is really proving itself to be effective.
LIISTRO: Yes, drug-eluting technology, whether stent-based or drug-coated balloon based, is more effective compared with simple nitinol stenting.
VDM: Will DRASTICO include any substudies on different patient populations?
LIISTRO: Yes, DRASTICO will include a substudy on those with critical limb ischemia vs patients with claudication, but the most important patient subgroup in my opinion is those who will have 1-month duplex follow-up showing already significant stenosis, because the limitation of this technique is what you leave at the end of the procedure. If you do not have an optimal result, you will pay in the long term with restenosis. In my opinion, in the future, we have to add a functional assessment of the vessel. We cannot base our intervention on angiography, because it is limited, so we should control the result of our angioplasty before we apply any drug therapy, and I think this would provide better results and lower restenosis rates.
VDM: So you think improved testing and evaluation ahead of time for better patient selection are important?
LIISTRO: I believe that if you embrace the DCB technology, you should apply it only after optimal angioplasty. But optimal angioplasty from an angiographic point of view is a poor concept because you have a lumen, and maybe a dissection, but you do not know if the dissection is important. You can say it’s a flow-limiting dissection, but we don’t have the measure to tell us that one dissection is dangerous and another one isn’t dangerous. If you have a dissection and use the duplex ultrasound, you can see by the increase in the velocity of the flow that a dissection is important. In my opinion, as we do for below-the-knee, we should apply this DCB technology only after an optimal result, regardless of whether you’ve used DCB, atherectomy, or perhaps a new device. This new approach to lesions will provide a better result.