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Matteo Tozzi, associate professor of Vascular Surgery at the University of Insubria (Varese, Italy), speaks to Vascular News about a new analysis related to the residual presence of paclitaxel in the bloodstream after the use of a drug-coated balloon (DCB) in arteriovenous fistulas (AVFs).
Can you tell us more about this new analysis?
Our study aims to investigate, in humans, the presence of the drug in the circulatory system at various time intervals after DCB use. Currently in the literature we have experimental data in animals, but not in humans. The method used, thanks to collaboration with Loredano Pollegioni and Luciano Piubelli of the laboratory The Protein Factory 2.0 of the University of Insubria, is high-performance liquid chromatography (HPLC), which is a particularly sensitive instrumentation that has allowed us to evaluate the presence of paclitaxel in the blood samples taken. The concentration of the drug, present only in the samples immediately following DCB deployment, reaches concentrations below 20nmol/L. Such low concentrations confirm that these dosages are far below those that can be tolerated, thus they cannot have systemic effects according to the ‘dose–effect’ principle.
In your opinion, why is this study important?
I believe that this study can add to the abundant evidence in the literature supporting the safety of DCBs. Currently, the strength of the clinical and experimental evidence is extremely strong—even for those who are very suspicious of the efficacy and safety of paclitaxel in the treatment of neointimal hyperplasia.
Did the decision to perform this analysis come from your daily practice?
Our use of DCBs never stopped. Clinical data on the follow-up of patients undergoing peripheral treatment have always assured us of their first-line role. The DCBs in use today offer the most effective treatment since they respond to the pathophysiology of neointimal hyperplasia.
Safety is a hot and sensitive topic: how important is it for you, and it is the key feature you are looking for in a DCB?
Safety is of primary importance with any medical treatment. For this reason, we are convinced that our study will bring positive evidence on this issue. The other aspect is treatment efficacy: this is directly related to the amount of drug that can be delivered to the target lesion. This feature is determined by the DCB coating, which characterises the influence of the paclitaxel uptake to the vessel wall. It must also avoid drug dispersion during radiological manoeuvres and blood navigation.
Such low concentrations of paclitaxel in the bloodstream, as found in our study, may provide us the proof that the Safepax® (Cardionovum) coating, thanks to its non-crystalline structure, effectively limits the drug dispersion in blood.
In terms of clinical outcome, we published an article evaluating the safety and efficacy of this technology using the Aperto® (Cardionovum) over-the-wire (OTW) DCB for the management of venous stenosis in arteriovenous grafts and AVFs in patients undergoing haemodialysis. The results coming from 311 angioplasty procedures in 200 patients are extremely positive with a freedom from restenosis of 88% at six months and 64% at 12 months.
The results of a recently published multicentre randomised clinical trial reinforced these positive data. In this study, more then 160 patients were analysed and at six months, the percentage with target lesion primary patency in the DCB group was significantly superior to that in the control group (high-pressure plain balloon) as well at 12 months in clinically driven target lesion revascularisation.
Do you believe that this analysis could be repeated in other anatomical areas such as the superficial femoral artery?
Our study has just started; these are the preliminary data related to the treatment of vascular access stenosis. However, we will also enrol patients undergoing peripheral and coronary revascularisations with DCBs.
The balloon sizes—and the distinct haemodynamic differences—are also very interesting to investigate, although we do not expect any significant change in the drug concentration in the bloodstream.
Disclaimer: Not approved in the USA