Initial Experience with Alcohol Septal Ablation Using a Novel Magnetic Navigation System

Abstract

We compared the use of magnetically assisted intervention (MAI) with conventional guidewire techniques to perform alcohol septal ablation (ASA) in patients with hypertrophic obstructive cardiomyopathy (HOCM). Treatment of symptomatic patients with HOCM using ASA has been established as an effective therapy. However, in many cases cannulaton of the septal artery can be technically challenging. Recently, a magnetically directed guidewire system has been developed to assist in navigation in difficult percutaneous interventions. By directing the guidewire to the septal branch, this system has potential to shorten the procedure time and increase success and safety of ASA in patients with HOCM. From October 2004 through October 2006, 44 consecutive patients underwent ASA using MAI with the Niobe system (Stereotaxis, Inc., St. Louis, MO). We compared these patients to 29 age- and gradient-matched cases using conventional techniques performed by an operator with >100 prior cases. All procedures were successful. Both the MAI and conventional groups had improved symptoms, exercise times, and reduced gradients compared with baseline. One dissection occurred in the conventional group. Although there were no aggregate differences in acute or 3-month clinical outcomes, the time required for guidewire cannulation of the septal branch decreased progressively with increasing experience (third tertile vs first tertile (3 [1.25-4.75 vs 10.5 [6-17] minutes, P = 0.004) compared with the conventional group (6 [2-10.25] minutes, P = 0.075 vs third tertile), suggesting a learning curve for MAI. MAI has the potential to improve wiring time and outcomes of HOCM patients undergoing ASA.