Summary from the Circulatory System Devices Panel Meeting - November 20, 2008
A meeting of the Circulatory System Devices Panel was held on November 20, 2008. The Panel discussed the submission, made several specific recommendations, and voted on the premarket approval application (P030031/S011) for the Biosense Webster NaviStar ThermoCool irrigated RF ablation catheter.
The Biosense Webster NaviStar ThermoCool Diagnostic/Ablation Catheter is currently approved for catheter-based cardiac electrophysiological mapping (stimulating and recording), and when used with the Stockert 70 Generator, for the treatment of:
- Type I atrial flutter in patients age 18 or older; and
- Recurrent drug/device refractory sustained monomorphic ventricular tachycardia (VT) due to prior myocardial infarction (MI) in adults.
The PMA application requests to expand the indication for use to include “treatment of drug refractory symptomatic paroxysmal atrial fibrillation”.
The device family consists of five distinct models of open-lumen, irrigated tip, radiofrequency (RF) cardiac ablation catheters. The device is inserted through the venous circulation to the heart, is passed across the intra-atrial septum to the left atrium, and ablates cardiac tissue to create lines of block in the atria to eliminate conduction patterns that theoretically generate or allow propagation of electrical waves responsible for paroxysmal AF.
The study was a prospective, randomized, unblinded, multi-center pivotal clinical investigation involving 19 centers and 167 subjects with symptomatic paroxysmal AF who were refractory or intolerant to antiarrhythmic drug (AAD) therapy. Patients were randomized 2:1, AF ablation treatment to medical therapy. The primary safety endpoint was adverse events occurring during the 7 days following the procedure as compared to the pre-specified performance goal of 16% (upper 95% confidence bound) adverse event rate. Patients were followed for a total of 12 months post-ablation, the last 9 months of which composed the effectiveness evaluation period. The primary effectiveness endpoint (chronic effectiveness) was assessed at the end of the 12 month follow-up period and compared to the control arm for superiority. Although approval was sought for 5 catheter modules, t he sponsor tested one device model in the clinical study to support the expanded indication.
The sponsor presented data from their clinical investigation which demonstrated that the study met the primary effectiveness endpoint, that is, ablation was superior to medical therapy for treatment of symptomatic paroxysmal AF. The sponsor also presented data which demonstrated that the study did not meet the primary safety endpoint.
Following presentations by the sponsor and the FDA, and after extensive deliberation, the Panel voted unanimously in favor of “Approvable with Conditions.” The recommended conditions of approval are summarized as follows:
- Limit approval to the NaviStar ThermoCool catheter with unidirectional deflection and equipped with a sensor compatible with the CARTO electroanatomic mapping system (this was the only catheter model tested in the clinical trial).
- Require the sponsor to establish a rigorous physician training program.
- Require the sponsor to establish a postmarket registry that is powered to collect data on the occurrence of pulmonary vein stenosis, the impact of the addition of the prophylactic cavo-tricuspid isthmus (CTI) lesion, and the effect of varying operator experience.
- Require the sponsor to perform a prospective study that assesses the use of the device in patients with a left ventricular ejection fraction less than 40%.
- Require the postmarket study to prospectively assess the impact of the addition of the prophylactic CTI lesion to the left atrial lesion set that was performed in the premarket study.
Contact: James Swink, Executive Secretary,
(240) 276-4179 James.Swink@fda.hhs.gov
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