Drug delivery by angiographic contrast media: inhibition of restenosis

Current status, challenges and future directions of drug-eluting balloons

For the past 30 years, contemporary coronary and endovascular interventions utilized balloon catheters, bare metal- and drug-eluting stents (DES) to recanalize narrowed vessels. Despite this, the quest for outcome optimization is ongoing for specific lesions and patients. Drug-eluting balloons (DEBs) are among the latest technologies proposed to overcome the limitations of DES, such as stent thrombosis and the dependency on long-term dual antiplatelet therapy. In the large part, DEBs were introduced as a substitute for DES in the treatment of in-stent restenosis and perhaps in certain de novo lesion subsets. DEBs have been tested in several clinical scenarios with encouraging preliminary results. This article will discuss the rationale for developing DEBs, basic concepts and available DEB platforms, along with preclinical studies and clinical experience to support the use of this new technology for endovascular interventions.

Intravascular drug release kinetics dictate arterial drug deposition, retention, and distribution

Millions of patients worldwide have received drug-eluting stents to reduce their risk for in-stent restenosis. The efficacy and toxicity of these local therapeutics depend upon arterial drug deposition, distribution, and retention. To examine how administered dose and drug release kinetics control arterial drug uptake, a model was created using principles of computational fluid dynamics and transient drug diffusion-convection. The modeling predictions for drug elution were validated using empiric data from stented porcine coronary arteries. Inefficient, minimal arterial drug deposition was predicted when a bolus of drug was released and depleted within seconds. Month-long stent-based drug release efficiently delivered nearly continuous drug levels, but the slow rate of drug presentation limited arterial drug uptake. Uptake was only maximized when the rates of drug release and absorption matched, which occurred for hour-long drug release. Of the two possible means for increasing the amount of drug on the stent, modulation of drug concentration potently impacts the magnitude of arterial drug deposition, while changes in coating drug mass affect duration of release. We demonstrate the importance of drug release kinetics and administered drug dose in governing arterial drug uptake and suggest novel drug delivery strategies for controlling spatio-temporal arterial drug distribution.