Intravascular ultrasound-guided intervention in patients with chronic total occlusion

Findings were reported today at the 26^th annual Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium. 

A chronic total occlusion is a complete or nearly complete blockage of a coronary artery that has been present for more than 30 days. PCI of CTO lesions is one of the most challenging forms of PCI, with some of the highest rates of recurrent restenosis due to the complexity of the procedures and lesions. IVUS evaluates coronary arteries using sound waves, and can be used to optimize post-PCI stent results, but whether there is demonstrable efficacy of this technique has not been adequately studied in CTO PCI.

The prospective, multi-center trial randomized 402 patients with CTOs to either the IVUS-guided or angiography-guided groups after successful guidewire crossing. Patients were then additionally randomized to zotarolimus-eluting stents or biolimus-eluting stents. The primary endpoint was the composite of cardiac death, myocardial infarction, and target-vessel revascularization (TVR) at 12 months. Secondary endpoints included a composite rate of cardiac death or myocardial infarction and individual components of the primary endpoint.

After a 12-month follow up, occurrence of the primary endpoint was significantly lower in the IVUS-guided group compared to the angiography-guided group (2.6 percent vs. 7.1 percent; hazard ratio=0.35, 95% CI=0.13-0.97; p=0.035). Occurrence of the composite of cardiac death and myocardial infarction was also significantly lower in the IVUS-guided group vs. the angiography-guided group (p=0.045). IVUS guidance led to more aggressive balloon inflations during PCI. At follow-up, TVR was non-significantly lower in the IVUS-guided group compared with the angiography-guided group (2.6 percent vs. 5.2 percent; hazard ratio=0.48, 95% CI=0.17-1.42; p=0.186).

Cross-over rates were 2.5 percent from IVUS-guided to the angiography-guided group, and 17.4 percent from angiography-guided to the IVUS-guided group (p<0.001). Based on the per-protocol analysis, occurrence of the primary endpoint was lower in the IVUS-guided group than in the angiography-guided group (2.2 percent vs. 8.4 percent; hazard ratio=0.26, 95% CI=0.09-0.71; p=0.005).

"This first-of-its kind trial demonstrates that compared with conventional angiography-guided CTO intervention, IVUS-guided intervention significantly improved 12-month clinical outcomes after new-generation drug-eluting stent implantation," said lead investigator Yang-Soo Jang, MD, PhD. Dr. Jang is Director of the Research Institute at the Severance Cardiovascular Hospital and Research Institute and Yonsei University Health System in Seoul, Korea.

"Findings show that IVUS-guidance for CTO intervention is superior to the conventional approach."