‘Jackhammer’ helps unblock arteries
TORONTO(CP) — In what’s being touted as a world first, Montreal researchers have busted open coronary arteries completely blocked with calcium deposits using an innovative device that produces a jackhammer effect.
Doctors at the McGill University Health Centre are testing the SoundBite Active Wire in a small group of patients who have "chronic total occlusion" of one of their coronary arteries, which severely restricts blood flow to the heart.
Principal researcher Dr. Stephane Rinfret, chief of interventional cardiology at MUHC, said Wednesday the condition affects about 20 per cent of people with coronary atherosclerosis, often called hardening of the arteries.
Interventional cardiologists typically treat arteries with varying degrees of plaque buildup using angioplasty — a procedure in which a fine guide wire and catheter are fed into the blood vessel and a tiny balloon is inflated to widen the opening. A stent is usually inserted to keep the vessel clear and blood flowing freely.
But with chronic total occlusion, or CTO, safely breaching a wall of rock-like calcium with a traditional guide wire is a highly complex, time-consuming procedure, which many interventional cardiologists are reluctant to perform because it can have a poor success rate, said Rinfret, who specializes in complex angioplasties.
Between 10 and 50 per cent of all CTO angioplasties are unsuccessful, primarily because ordinary wires can't break through the wall of calcium, he said.
The SoundBite guide wire, developed by a Quebec company named SoundBite Medical Solutions, provides a new twist that could help increase success rates.
The wire is connected to a shock wave generator, which causes it to vibrate like a jackhammer inside the artery, allowing it to create cracks in the calcium blockage while leaving the walls of the blood vessel unharmed.
“This wire could mean the difference between the success and failure of a CTO angioplasty because it will be able to break through areas where other guides fail to penetrate,” said Rinfret. “It will clear the way and allow us to treat the diseased artery.”
Animal studies have shown the device doesn't pulverize the calcium blockage to create debris — which could lead to heart attackcausing clots — but opens up tiny fissures that allow a second guide wire and balloon catheter to pass through.