Restenosis inhibition by non-stent-based local drug delivery
Drug-eluting stents have shown strong anti-restenotic effects in clinical trials. Their efficacy was believed to depend on the sustained release of antiproliferative drugs. Paclitaxel added to an angiographic contrast medium (CM) and paclitaxel-coated balloon catheters were tested as alternative options for transferring the drug to the vessel wall. Animal studies and studies in patients conducted or initiated by us were first indicating persistent efficacy of drugs even after very short exposure of the vessel wall. More recent results show persistent restenosis inhibition for 5 years after a single treatment with no recognizable local or systemic drug-induced adverse effects.
Important aspects of the clinical use of the coated balloons have been investigated in a large number of experimental and clinical studies:
- Transfer of the drug to the vessel wall
- Efficacy of a variety of drugs and formulations
- Impact of inflation time
- Impact of the inflation pressure
- Dose response including impact of overdose
- Efficacy and tolerance in various vessel territories
A rational and proven testing sequence of new drug coatings addressing potential problems at an early stage has been established.
Transversal slices through porcine coronary arteries with stent 4 weeks following uncoated (left) and drug coated ballon treatment (right)