Medtronic has presented data from the STOP AF (Sustained Treatment of Paroxysmal Atrial Fibrillation) clinical trial which showed superiority over anti-arrhythmic drugs, with paroxysmal atrial fibrillation (PAF) patients treated with the Arctic Front Cardiac CryoAblation Catheter System.
Medtronic said that the STOP AF pivotal clinical trial has studied the safety and effectiveness of the Medtronic Arctic Front Cardiac CryoAblation Catheter System in paroxysmal AF patients as compared to drug therapy.
Patients were randomized to receive either cryoablation or anti-arrhythmic drug therapy. For every three patients enrolled, approximately two received an ablation and one was randomly assigned to the drug therapy group. Twenty-six US and Canadian centers enrolled 245 patients (163 cryoablation and 82 anti-arrhythmic drugs). Outcomes on all patients were assessed through 12-months of follow-up.
The results are part of the PMA submission in consideration for FDA approval for the Medtronic Arctic Front Cardiac CryoAblation Catheter System. The primary effectiveness outcome was treatment success and was defined as having both acute procedural success and freedom from chronic treatment failure for those patients randomized to cryoablation. Acute procedural success was defined as demonstration of electrical isolation in three or more pulmonary veins at the conclusion of the first cryoablation procedure.
Medtronic said that the two primary safety outcome measures were Cryoablation Procedure Events (CPEs) in cryoablation subjects and Major Atrial Fibrillation Events (MAFEs) in both study groups. The data indicate that both primary safety outcomes were met.
The trial also captured safety data on several of the complications of any ablation procedure in 228 patients that underwent cryoablation procedures including those randomized to cryoablation and those who crossed over for cryoablation after failing drug therapy. Phrenic nerve palsy, a recognised observation with this technology, was noted after 11.2% of all cryoablation procedures in 228 patients.
The Medtronic Arctic Front Cardiac CryoAblation Catheter System is designed to be used with fluoroscopy and does not require the use of complex, three-dimensional electroanatomical mapping systems. The System is available for use in Europe and certain other countries outside the US and is under investigational use in the US.
Kevin Wheelan, chief of staff at Baylor Heart and Vascular in Dallas and investigator with the STOP AF trial, said: “These data are a promising indication of the safety profile of cryoablation and its effectiveness in isolating the pulmonary veins to stop AF. The cryoballoon demonstrated strong results in treating PAF patients who had previously failed drug treatment.”