Photoablation using the turbo-booster and excimer laser for in-stent restenosis treatment: twelve-month results from the PATENT study.
PURPOSE
To evaluate the performance of the Turbo Elite laser catheter in combination with the Turbo-Booster guiding catheter for the treatment of femoropopliteal in-stent restenosis (ISR).


METHODS
The PATENT study (Photoablation Using the Turbo-Booster and Excimer Laser for In-Stent Restenosis Treatment) was a multicenter prospective industry-sponsored registry involving 5 European centers. Patients with symptomatic femoropopliteal ISR (Rutherford categories 2-5) and an ankle-brachial index ≤0.8 were treated with excimer laser atherectomy (ELA). Ninety patients (65 men; mean age 69.5±9.3 years) were enrolled. The majority of patients were Rutherford category 3 (63, 71.6%), and 32 (35.6%) patients had previous treatment for ISR. The average lesion length was 123±95.9 mm, and 30 (34.1%) lesions were total occlusions. The main efficacy outcome was primary patency at 12 months as measured by duplex ultrasonography. The primary safety outcome was freedom from major adverse events (MAE) during hospitalization and at 30-day follow-up to include all death, unplanned major amputation, or target lesion revascularization (TLR).


RESULTS
The Turbo Elite laser catheter created a pilot channel in 87 (96.7%) of 90 lesions, with a mean of 1.5 passes, followed by the Turbo Booster with a mean of 5.7 passes. Adjunctive balloon dilation was performed in 79 (87.8%) lesions. Procedure success (<30% residual stenosis without stenting) was 96.7%. The mean percentage stenosis improved from a baseline of 87.0% to 32.3% after laser atherectomy and to 7.4% after final treatment. The MAE rate through 30 days was 2.2%. Nine (10.0%) patients experienced distal embolization. Estimates of freedom from TLR at 6 and 12 months were 87.8% and 64.4%, respectively. Primary patency at 6 and 12 months was 64.1% and 37.8%, respectively. Only a history of prior intervention for ISR (p<0.01) was a predictor of TLR at 12 months.


CONCLUSION
The PATENT study has established excimer laser atherectomy as safe for the treatment of femoropopliteal ISR, achieving high procedure success. Recurrence of restenosis indicates that removing hyperproliferative tissue alone does not solve the problem of ISR. New concepts, such as the combination of ELA with drug-eluting balloons, may prove beneficial.