To determine and analyse the success rate and key operational points of a new technique of opening the coronary chronic total occlusion (CTO) lesions: Crow Bar Effect.Methods and procedure of crowbar effect technique
48 patients with coronary CTO lesions receiving interventional approaches through the crow bar effect (Crow Bar Group) and 72 patients with CTO receiving classical ante-grade guide wire technique (Control Group) were investigated from February 2007 to December 2012. All patients in groups suffered from unstable angina pectoris with the grade 2–4 level lasting for six months and over. There was no statistically significant difference in the distribution of gender, age and duration of vascular occlusion between groups (p > 0.05).Methods and procedure of crowbar effect technique
No-hydrophilic-coated and moderately stiff guide wire was firstly used to puncture fibre cap of proximal segment of CTO lesions into distal vessel under the supporting with micro-catheter or small balloon, and was confirmed by multi-angle CAG judgment into the true lumen. When the balloon was pushed to be unable to get in the lesions, the second guide wire (with hydrophilic coating) along the first thread trace was pushed through the lesions to distal vessel. As following the third guide wire (super stiff guide wire with hydrophobic-coated was usually selected) was inserted into lesions to distal vessel.Then, small balloon (diameter 1.25 mm) was pushed along a guide wire into the lesions. When the small balloon was not still pushed to insert the lesions, small balloon under keeping certain push force condition was repeatedly dilated with high pressure (12–16 atm). After high pressure expansion of balloon at every time the balloon was able to make forward 2–3 mm, and slowly passed through the lesions to distal vessel so repeatedly. After the over procedure a softer guide wire was retained in the vessel, per-dilatation was completed with larger balloon (routinely 2.0 × 20 mm balloon), and then DES was implanted.Methods and procedure of crowbar effect technique
This expansion force of small balloon with high pressure repeatedly push another two guide wires on both sides to pry dense fibro-plaque tissue of coronary occlusion lesions and to make the channel which small balloon can enter into. This role is called crowbar effect technique.Results
The success rate of PCI procedure was 89.6% in Crow Bar Group and 73.6% in Control Group and difference in the success rate is statistically significant (P < 0.05). The occurrence rate of the complication was 8.3% in Crow Bar Group and 5.6% in Control Group, and the difference in the complication between groups was not statistically significant (P > 0.05). Coronary artery perforation was the major complication which was mostly caused by the puncture of the guide wire into external wall of the vessel, but there was no serious consequence.Conclusion
The new technique of crow bar effect is an effective and simple approach to open CTO lesions with a high success rate. When the balloon can't pass through CTO lesions, this method may be used to increase the success rate of opening CTO lesions.