Radiofrequency ablation for totally occluded coronary arteries

A minimally invasive technology for clearing totally blocked coronary arteries may allow more patients to be treated with coronary angioplasty and stenting procedures rather than with open heart surgery.

Waveform communication guides the use of the Safe Cross® system in an arterial occlusion.

Photo courtesy of Intraluminal Therapeutics Inc.

The Safe-Cross® Radiofrequency Total Occlusion Crossing System combines a visual display and guidance technology with radiofrequency energy delivered through a catheter guide wire to burn through blockages in coronary arteries.

The "optical coherence reflectometry" guidance system allows physicians to monitor the proximity of the wall of the artery to avoid puncturing it; the radiofrequency energy automatically shuts off if the catheter comes too close to the artery wall. Once the guide wire has passed through the total occlusion, it can be treated with conventional angioplasty and stent devices.

Who might benefit

Each year about 40,000 Canadians undergo balloon catheter angioplasty to clear blockages in their coronary arteries.[1]

However, for patients with chronic total occlusion (CTO), the artery is completely blocked, making it difficult for the guide wire to pass through. About one-third of patients with suspected or known coronary artery disease have CTO.[2] Many patients with CTO are not considered suitable candidates for angioplasty, and may be offered drug treatment and/or coronary artery bypass surgery instead.

Current regulatory status

Health Canada licensed the Safe-Cross Radiofrequency Total Occlusion Crossing System (IntraLuminal Therapeutics Inc., Carlsbad, CA) in August 2003. The Safe-Cross system has not yet been used in Canada, but has been available in Europe for several years and in the US since early 2004.[3]

Evidence

The Safe-Cross system was evaluated in a prospective registry study of 116 patients with CTO of coronary arteries. All patients had previously undergone unsuccessful attempts at angioplasty with conventional guide wires. The Safe-Cross system achieved successful crossing of the CTO in 63 patients (54.3%).[3] Eight patients (6.9%) experienced major adverse events (myocardial infarction or perforation of the artery). Perforations occurred in three patients (2.6%); however the perforation was linked to use of the Safe-Cross device in only one patient (0.9%). No deaths occurred and no emergency bypass surgeries were needed.

Cost

The Safe-Cross console and generator cost US$45,000. Lease or rental options are available. The disposable items used for each procedure cost US$1,600. Further evidence is needed to determine if device costs are offset by cost savings in shorter hospital stays, improved patient outcomes and quality of life.

References

[1] Centre for Chronic Disease Prevention and Control, Health Canada, et al. The growing burden of heart disease and stroke in Canada. Ottawa: Heart and Stroke Foundation of Canada; 2003. Available: http://www.cvdinfobase.ca/cvdbook/CVD_En03.pdf .

[2] Kahn JK. Am Heart J 1993; 126(3 Pt 1):561-4.

[3] Baim DS, et al. Am J Cardiol 2004; 94(7):853-8.