Paclitaxel balloon coating, a novel method for prevention and therapy of restenosis.

BACKGROUND: Drug-eluting stents have shown promising antirestenotic effects in clinical trials. Non-stent-based local delivery of antiproliferative drugs may offer additional flexibility and also reach vessel areas beyond the immediate stent coverage. The aim of the present study was to evaluate a novel method of local drug delivery based on angioplasty balloons. METHODS AND RESULTS: Stainless steel stents (n=40; diameter, 3.0 to 3.5 mm; length, 18 mm) were implanted in the left anterior descending and circumflex coronary arteries of domestic pigs. Both conventional uncoated and 3 different types of paclitaxel-coated, percutaneous transluminal coronary angioplasty balloons (contact with vessel wall for 1 minute) were used. No difference in short-term tolerance between coated and uncoated balloons and no signs of thrombotic events were observed. Quantitative angiography and histomorphometry of the stented arteries asserted the statistical equality of the baseline parameters between the control and the 3 treatment groups. Paclitaxel balloon coating led to a marked, dose-dependent reduction of parameters characterizing in-stent restenosis (reduction of neointimal area up to 63%). Despite the marked reduction in neointimal proliferation, endothelialization of stent struts was present in all samples. There was no evidence of a significant inflammatory response in the neighborhood of the stent struts. CONCLUSIONS: Paclitaxel balloon coating is safe, and it effectively inhibits restenosis after coronary angioplasty with stent implantation in the porcine model. The degree of reduction in neointimal formation was comparable to that achieved with drug-eluting stents.

Laser-induced thermotherapy (LITT) of liver metastases: MR-guided percutaneous insertion of an MRI-compatible irrigated microcatheter system using a closed high-field unit.

PURPOSE: To evaluate the efficacy and safety of a new MRI-compatible irrigated laser microcatheter system for thermal ablation of liver metastases. MATERIAL AND METHODS: The new microcatheter system consists of a titanium needle with a diameter of 1.5 mm and a surrounding Teflon catheter with an outer diameter of 1.8 mm (5.5 F). In vitro laser-induced coagulation of bovine liver tissue was performed to determine the optimal perfusion rate of cooling saline flow, maximum laser energy, and ablation time. Laser-induced thermotherapy using the new microcatheter system, an Nd:YAG laser (Dornier), and a flexible laser light guide (Somatex GmbH, Berlin, Germany) was performed in 28 patients with liver metastases. Percutaneous insertion and positioning of multiple microcatheters in the lesion and monitoring of therapy was performed with a closed high-field MRI scanner using T1-weighted gradient-echo sequences during breath-hold. RESULTS: A perfusion rate of 0.75 mL/minute, a laser energy of 15 W, and an ablation time of 20 minutes were found suitable to achieve safe and sufficient ablation of metastatic tissue. The mean volume of induced coagulation in vitro was 23.9 mL. Ablation of liver metastases in patients was technically and clinically successful. CONCLUSION: The new microcatheter system allows for both catheter placement and monitoring of therapy using a single imaging modality. This shortens the procedure and enables more precise puncture and therapy of liver metastases. Due to the miniaturized design of the catheter and the real-time monitoring, the procedure is minimally invasive and very well tolerated by patients. This new technique seems to be a safe and feasible alternative in treating liver metastases.